WO1998045621A1

WO1998045621A1 - In-line multi-gear transmission system and multi-gear wheel hub in a helical drive system

Info

Publication number: WO1998045621A1
Application number: PCT/IB1998/000598
Authority: WO
Inventors: Mighel Doroftei
Original assignee: Helical Dynamics International Inc.
Priority date: 1997-04-07
Filing date: 1998-04-06
Publication date: 1998-10-15

Abstract

An in-line multi-gear transmission system (46, 48) having an input carrier assembly (188) coupled to an output portion of a helical drive (190) such that an axis of rotation of the input carrier assembly (188) is substantially aligned with an axis of rotation of the output portion of the helical drive (190). A gear assembly (186) in the in-line multi-gear transmission system (46, 48) and a multi-gear hub (502) transfer rotational energy from an input portion to an output portion of the gear assembly (186).

Description

IN-LINE MULTI-GEAR TRANSMISSION SYSTEM AND MULTI- GEAR WHEEL HUB IN A HELICAL DRIVE SYSTEM

BACKGROUND OF THE INVENTION

1 Field of the Invention

The present invention pertains to a transmission system for changing the gear ratio between an input portion and an output portion thereof, and, in particular, to an in-line multi-gear assembly and a multi-gear wheel hub both of which permit changing of the gear ratio, a helical drive transmission system employing the in-line multi-gear assembly and/or the multi-gear wheel hub, a method for transmitting power at different gear ratios from a helical drive to a driven wheel, and a bicycle utilizing such a helical drive transmission system 2. Description of the Related Art

A conventional bicycle includes a pair of pedals mounted onto a crank shaft having a main driving sprocket affixed thereto. Input power provided by the rider to the pedals is typically transferred from the driving sprocket to the rear wheel of the bicycle via a chain loop that extends between the main driving sprocket and a rear driven sprocket mounted on the hub of the rear wheel. The gear ratio in such a bicycle is typically altered by providing a plurality of different sized sprockets for the main driving sprocket and/or the rear driven sprocket. One or more derailers physically move the chain between the different sized sprockets, thereby altering the gear ratio.

This conventional bicycle drive system has been improved upon by the invention disclosed in U.S. Patent application no. 08/711,982 ("the '982 application"), in which the chain drive system is replaced with a human powered helical drive system. The helical drive system transmits power to the driving wheel more efficiently than a conventional chain drive system. The structure, function, other advantages and various applications and embodiments of the helical drive are discussed in detail in the '982 application as well as in the above- identified U.S. provisional patent applications.

The helical drive disclosed in the '982 application transmits power provided by the user to the rear wheel of the bicycle at only one transmission

(gear) ratio. It is desirable, however, to have the ability to alter the transmission ratio so that the same input torque or input power provides different alternative levels of output torque or output power to the driving wheel. Altering the transmission ratio enables the bicycle rider to maintain the same cadence (pedaling speed) regardless of the cycling conditions, so that if the bicycle is traveling up hill, for example, where a larger output torque is needed, the transmission ratio can be reduced thereby making pedaling easier. Conversely, if the bicycle is traveling on level terrain, the transmission ratio can be increased so that bicycle travels faster under the same cadence. SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide a transmission system for use with a helical drive that permits changing of the transmission ratio between the output of the helical drive and the output of the transmission system. In a first embodiment of the present invention this object is achieved by providing an in-line multi-gear assembly that includes an input carrier assembly operatively coupled to the output portion of a helical drive such that an axis of rotation of the input carrier assembly is substantially aligned with an axis of rotation of the output portion of the helical drive. A gear assembly coupled to the input carrier assembly has a plurality of gears selectively engageable in various combinations to provide a selectively variable transmission ratio. An output assembly is coupled to the output of the gear assembly. The gear assembly includes a ratchet shell cap rotateably connected to the helical drive, a ring gear carrier concentrically located inside the ratchet shell cap, and .a planetary gear carrier assembly concentrically located inside the ring gear carrier. The ring gear carrier assembly and the ratchet shell cap are adapted to be rotateably engaged such that a rotation of the input carrier assembly induces a rotation of the output assembly at a first transmission ratio. The input carrier assembly, ring gear carrier assembly, planetary gear carrier assembly and output assembly are adapted to be rotateably engaged such that a rotation of the input carrier assembly induces a rotation of the output assembly at a second transmission ratio. Finally, the input carrier assembly, planetary gear carrier assembly, ring gear carrier assembly and ratchet shell cap are adapted to be rotateably engaged such that a rotation of the input carrier assembly induces a rotation of the output assembly at a third transmission ratio.

In a second embodiment of the present invention this object is achieved by providing a multi-gear wheel hub having two input gears and a gear assembly associated therewith. Each input gear is coupled to an output portion of the helical drive such that the axis of rotation of the input gear is at a non-zero angle relative to the axis of rotation of the output portion of the helical drive. The gear assembly includes a main shaft, a bushing rotateably mounted on an end portion of the main shaft, an orbital shaft coupled to the bushing such that rotation of bushing causes the orbital shaft to orbit the main shaft. A rotating member rotates about the main shaft outside an orbit of the orbital shaft. First and second stationary gears are mounted on the main shaft. First and second orbital gears are rotateably mounted on the orbital shaft. Also, first and second ring gears are mounted on the rotating member. A shifting mechanism alternatively positions the first orbital gear in an engaged relationship with the first stationary gear and the first ring gear and positions the second orbital gear in an engaged relationship with the second stationary gear and the second ring gear. When the first orbital gear engages the first stationary gear and first ring gear, the orbital movement of the orbital shaft about the main shaft induces a rotation in the first orbital gear that is transferred to the first ring gear, thereby rotating the rotating member at a first transmission ratio. When the second orbital gear engages the second stationary gear and second first ring gear, orbital rotation of the orbital shaft about the main shaft induces a rotation in the second orbital gear that is transferred to the second ring gear, thereby rotating the rotating member at a second transmission ratio. The diameters of the first and second stationary gears, first and second orbital gears, and first and second ring gear selected such that the first transmission ratio is different from the second transmission ratio.

No prior multi-gear wheel hub has dual input gears, one on each end of the hub.

It is a further object of the present invention to provide a bicycle having a helical drive assembly that permits changing of the transmission ratio. This is accomplished by providing a helical drive transmission system employing the inline multi-gear assembly and/or the multi-gear wheel hub described above for transmitting power at different gear ratios from a helical drive to a driving wheel. It is yet another object of the present invention to provide a method of transmitting power output from a helical drive to a driven wheel at selective, alternative transmission ratios. This object is achieved by providing the steps of providing input power to an input portion of a first helical drive, transferring rotational energy from an input portion of a transmission system to an output portion thereof, wherein the transmission system has a selectively variable transmission ratio using the above described in-line multi-gear transmission system and or the multi-gear hub to provide a variety of alternative transmission ratios for transferring rotational energy from the input portion to the output portion of the transmission system, and coupling the output portion of the transmission system to said drive member. These and other objects, features, and characteristics of the present invention, and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of the specification, wherein like reference numerals designate corresponding parts in the various figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is side view of a bicycle having a helical drive system for transmitting input power to a drive wheel according to a first embodiment of the present invention; Fig. 2 is a top view of the bicycle illustrated in Fig. 2;

Fig. 3 is an exploded view of the helical drive system including a helical drive and an in-line multi-gear transmission assembly;

Fig. 4 is a side view of the helical drive system illustrated in Fig. 3; Fig. 5A-5C are perspective views of a helical carrier assembly used in the helical drive system illustrated in Fig. 1;

Fig. 6 is a perspective view of helical shaft and input portion of the helical drive illustrated in Figs. 3-4; Fig. 7 is a perspective view of a retaining nut in an input carrier assembly used in the in-line multi-gear transmission assembly of Fig. 3;

Fig. 8 is a perspective view of an input carrier in the input carrier assembly used in the in-line multi-gear transmission assembly of Fig. 3; Fig. 9 is a perspective view of a ratchet shell cap used in the in-line multi- gear transmission assembly of Fig. 3;

Fig. 10 is a perspective view of a ring gear carrier used in the in-line multi-gear transmission assembly of Fig. 3;

Fig. 11 is a perspective view of a planetary gear carrier used in the in-line multi-gear transmission assembly of Fig. 3;

Fig. 12 is a perspective view of an output assembly used in the in-line multi-gear transmission assembly of Fig. 3;

Fig. 13 is a perspective view of an axle assembly used in the in-line multi- gear transmission assembly of Fig. 3 with an end plate connected thereto; Fig. 14 is a perspective view of a portion of a sifter cable assembly used in the in-line multi-gear transmission assembly of Fig. 3;

Fig. 15A-15E are perspective view of the components of a shifter mechanism used in the in-line multi-gear assembly of Fig. 3;

Fig. 16A is a side view of a bicycle having a helical drive system for transmitting input power to a drive wheel according to a second embodiment of the present invention;

Fig. 16B is a top view of the bicycle illustrated in Fig. 16A;

Fig. 17 is a cross-sectional view of a multi-gear hub according to the principles of the present invention; Fig. 18 is a cross-sectional view of an overrunning clutch used in the multi-gear hub of Fig. 17;

Fig. 19 is a side view of a bicycle having a helical drive system for transmitting input power to a drive wheel according to a third embodiment of the present invention; Fig. 20 is a top view of the bicycle illustrated in Fig. 19; Fig. 21 is a schematic illustration of a helical drive system used in the bicycle illustrated in Figs. 19-20;

Fig. 22 is a top view of a bicycle having a helical drive system for transmitting input power to a drive wheel according to a fourth embodiment of the present invention;

Fig. 23 is a schematic illustration of a helical drive system used in the bicycle illustrated in Fig. 22;

Fig. 24 is a top view of a bicycle having a helical drive system for transmitting input power to a drive wheel according to a fifth embodiment of the present invention;

Fig. 25 is a schematic illustration of a helical drive system used in the bicycle illustrated in Fig. 24;

Fig. 26 is a side view of a bicycle having a helical drive system for transmitting input power to a drive wheel according to a sixth embodiment of the present invention;

Fig. 27 is a top view of the bicycle illustrated in Fig. 26;

Fig. 28 is a top view of the drive system used in the bicycle illustrated in Figs. 25-26;

Fig. 29 is a side view of the drive system used in the bicycle illustrated in Figs. 25-26;

Fig. 30 is a side view of a bicycle having a helical drive system for transmitting input power to a drive wheel according to a seventh embodiment of the present invention;

Fig. 31 is a top view of the bicycle illustrated in Fig. 30; Fig. 32 is a side view of the drive system used in the bicycle illustrated in

Figs. 30-31 ;

Fig. 33 is a side view of a bicycle having a helical drive system for transmitting input power to a drive wheel according to an eighth embodiment of the present invention; Fig. 34 is a top view of the bicycle illustrated in Fig. 33; Fig. 35 is a top view of the drive system used in the bicycle illustrated in Figs. 33-34;

Fig. 36 is a side view of the drive system used in the bicycle illustrated in Figs. 33-34; and Fig. 37 is a perspective view of a polycycle having a helical drive system for transmitting input power to a drive wheel according to a first embodiment of the present invention.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EXEMPLARY EMBODIMENTS

Fig. 1 illustrates a bicycle 30 having a frame 32, a seat 33, handlebars 34, and front and rear wheels 35 and 36, respectively. In the illustrated embodiment, rear wheel 36 is driven by a helical drive system 38. Power is provided to helical drive system 38 via input devices 40, which in this embodiment, are actuated by the pedaling motion of the bicycle rider. Helical drive system 38 includes a first and a second helical drive assembly

42a and 42b for converting the pedaling motion of the bicycle rider into a rotational motion and a transmission assembly 45 for transferring the rotational motion from the helical drive assembly to the rear wheel. In the illustrated embodiment, transmission assembly 45 includes a first and a second in-line multi gear transmission assembly 46 and 48. Linear movement of an input device 40 in each helical drive assembly over an associated helical shaft 44 causes the helical shaft to rotate. The rotational motion at the output of the helical drive assembly is input to a transmission assembly 45. Details of the helical drive assembly, its various embodiments, and method of operation are described in the '928 application and in the provisional applications mentioned above, the contents of which are incorporated hereby by reference. The rotational motion produced by helical drive assembly 42 is transferred by transmission assembly 45 to rear wheel 36, which acts as a driving wheel for bicycle 30. In embodiment illustrated in Fig. 1, left and right helical drives 42a and 42b, respectively, are provided within or attached to the forks of frame 32 to which rear wheel 36 is also attached. In this embodiment, the rides leans forwards toward handlebar 34 and pedals while in a slightly prone position with his/her legs projecting generally toward the rear of the bicycle. Translational motion of the input devices is in the direction indicated by arrow X, which is in a plane intersecting a rear hub 47 of the bicycle.

Fig. 3 is an exploded view of a preferred exemplary embodiment of a helical drive system having an in-line multi-gear transmission assembly 46 or 48.

The structure for in-line multi-gear transmission assemblies 46 and 48 are identical and includes an end plate 52, an axle assembly 180, an output assembly 182, a gear assembly 186, an input carrier assembly 188, a shifter cable assembly 184, a helical drive 190 and a helical carrier assembly 192. Each of the components and their interactions is explained in detail below with references to Figs. 3-15.

In a preferred exemplary embodiment, the in-line multi-gear transmission system has three selectable transmission ratios. However, transmission systems with other transmission ratios (two, four, five or six, for example) are contemplated by this invention.

Fig. 4 illustrates an assembled helical drive system with a cutout view of a helical drive housing 62 that contains the components of the helical drive system. Helical drive housing 62 has a cylindrical shape with a hollow center.

A slot 66 defined along a longitudinal direction on helical drive housing 62 receives a portion of input device 40. Helical drive housing 62 also has a carrier end 198 to receive helical carrier assembly 192 and an output end 196 to receive output assembly 182 and an end plate 52. A cutout 64 is defined on an output end 190 of helical drive housing 62 to allow output assembly 182 to transfer rotational forces from in-line multi-gear assembly 46, 48 to a hub of rear wheel 36.

The following discussion will show prefeπed exemplary components of helical caπier assembly 192, input carrier assembly 188, gear assembly 186, shifter cable assembly 184, axle assembly 180, and output assembly 182. Subsequently, engaging mechanisms among all of the components will be discussed to show how in-line multi-gear transmission assembly 46a transmits rotational power received by input carrier assembly 188 to output assembly 182 with a number of different transmission ratios. As illustrated in Figs. 5A-5C, helical carrier assembly 192 has an end cap

106, a bearing 104, and a helical driver carrier 102. End cap 106 is to be fixedly and non-rotationally attached to carrier end 198 of helical drive housing 62 (see Fig. 4). A shifter cable 84 (Figs. 1, 2 and 14) passes through a hole 107 defined in the center of end cap 106. Helical carrier assembly bearing 104 is placed between end cap 106 and helical drive carrier 102.

Helical drive carrier 102 has a helical input device engaging mechanism. In the exemplary embodiment illustrated in Fig. 5C, the helical input device engaging mechanism is a slit 103 to receive one end of helical drive shaft 98 depicted in Fig. 6. Helical drive shaft 98 is a twisted bar with a hollow center 84 (which is only one exemplary embodiment of helical drive devices). Other types of helical drive devices are shown in the applications identified above. Helical drive carrier 102 can have a variety of configurations to correspond to the variety of helical drive devices so long as it is adapted to be rotated by rotational motion of the helical drive device. Figs. 7 and 8 illustrate components of a preferred exemplary embodiment of input carrier assembly 188. Input carrier assembly 188 includes an input carrier 94, preferably having a cylindrical shape, with a hollow center. Input carrier 94 has two surfaces: a helical drive locking surface 134, and a gear assembly locking surface 136. A helical drive engaging mechanism (not shown) is disposed on helical drive locking surface 134. The helical drive engaging mechanism on input carrier 94 serves a substantially identical function as helical drive carrier 102. In other words, the helical drive engaging mechanism on input caπier 94 receives an end of a helical drive device.

Gear assembly locking surface 136 has a number of tapered splines 132 protruding in the direction perpendicular to surface 136. Tapered splines 132 engage with gear assembly 186 to transfer rotational power from input carrier assembly 188 to gear assembly 186.

An input carrier bearing 130 is disposed at the outer surface of the hollow center of input carrier 94. The hollow center is sized to receive a retaining nut 96. Shifter cable 84 passes through a hole defined in a center of retaining nut 96.

Gear assembly 186 preferably has a number of gears selectively engageable in various combinations to transmit drive power in a various transmission ratios from input carrier assembly 188 to output assembly 182. In the embodiment illustrated in Fig. 3, gear assembly 186 includes a ratchet shell cap 92 with a ratchet shell cap engaging mechanism, a ring gear carrier assembly 90 with a number of ring gear carrier engaging mechanisms and a planetary gear carrier assembly 74 with a number of planetary gear carrier engaging mechanisms.

As illustrated in Fig. 9, ratchet shell cap 92 preferably has a cylindrical shape with a hollow center, and includes a bearing 170. In this exemplary embodiment, ratchet shell cap teeth 172 disposed about the inner surface of ratchet shell cap 92 serve as a ratchet shell cap engaging mechanism.

As illustrated in Fig. 10, ring gear carrier assembly 90 preferably has a cylindrical shape with a hollow center, a planetary gear carrier locking inner surface 157, an input carrier locking inner surface 155 and ring gear carrier engaging mechanisms. In this exemplary embodiment, the ring gear carrier engaging mechanisms include a number of cogs 154 disposed on input carrier locking inner surface 155, a number of retractable pawls 152 pivotally mounted on ring gear carrier 90 and a gear 156 disposed on planetary gear carrier locking inner surface 157. As illustrated in Fig. 11, planetary gear carrier assembly 74 preferably has a cylindrical shape with a hollow center, an input carrier locking surface 146 and planetary gear carrier engaging mechanisms. In this exemplary embodiment, the planetary gear caπier engaging mechanisms includes a number of planetary pinion gears 144 mounted on planetary gear carrier assembly 74, a number of pawls 140 pivotally mounted on planetary gear carrier assembly 74, and a number of carrier pins 142 protruding from input carrier locking surface 146. The pawls, both retractable pawls 152 of ring gear carrier assembly 90 and pawls 140 of planetary gear carrier assembly 74, are pivotally mounted on respective carrier assemblies such that they would preferably engage with other gears only in one direction but not in the other direction.

As illustrated in Fig. 12, output assembly 182 includes an output gear 70, a shell 72 and a bearing 68. As a preferred exemplary embodiment, output gear 70 is a bevel gear and shell 72 is fixedly attached to ratchet shell cap 92 (???). Preferably, output gear 70 is angled with respect to the axis of rotation of in-line multi-gear assembly 46a. In the exemplary embodiment depicted in Fig. 1, the rotational force is transferred from in-line multi-gear assembly 46, 48 a to a hub of rear wheel 36 at an angle of approximately 90 degrees.

Axle assembly 180 with end plate 52 connected thereto is illustrated in Fig. 13. In this exemplary preferred embodiment, axle assembly 180 includes an end plate end 53, an input assembly end 59 and a shifter slot arrangement 57, and a stationary sun gear 56. End plate 52 is fixedly and non-rotationally connected to end plate end 53 of axle assembly 180. In this preferred embodiment, end plate 52 is rigidly connected to output end 196 of helical drive housing 62 (as shown in Fig. 4). Stationary sun gear 56 is located on axle assembly 180 so as to engage pinion gears 144 of planetary gear carrier assembly 74 when the helical drive system is assembled.

Shifter slot arrangement 57 of axle assembly 180 preferably has a hollow center into which shifter cable assembly 184 is provided and a shifter slot 58. A protruding part of a shifter ring 78 extends through slot 58 to interact with gear assembly 186.

As illustrated in Figs. 14 and 15A-15E, shifter cable assembly 184 includes a shifter cable 84, cable pin 122, and cable pin threading 120, a spring 88, a pin lock 86 with grooves to receive a pin 80 which has notches on both ends, shifter ring 78 with an outer surface 77 and a number of protruding parts, and a bushing 76. Spring 88, pin lock 86, pin 80, shifter ring 84 and bushing 76 are mounted coaxially on shifter cable 84.

When the above mentioned components are assembled, input carrier assembly 188, gear assembly 186 and output assembly 182 are all coaxially mounted on axle assembly 180. Axle assembly 180 is preferably stationary. The rotational force is received from helical drive shaft 98 by input carrier assembly 188 and the rotational force is transferred through gear assembly 186 with a selected transmission ratio to output assembly 182.

The manner in which the above mentioned components engage to produce a number of transmission ratio is discussed hereon. In this exemplary embodiment, a transmission ratio is selected by a rider the using a shifter cable controller 49 (Fig. 1). Shifter cable controller 49 moves shift cable 84 according to the rider's selection, which in turn moves shifter cable assembly 184 to engage gear assembly 186. Shifter cable controller 49 is mounted on any part of bicycle 30 that can conveniently accessed by the rider. For example, shifter cable controller can be mounted on handlebars 34 or on frame 32. Any conventionally available shifter cable controller can be used as shifter cable controller 49. For example, shifter cable controller can be any one of the following: an indexed thumb controlled shifter cable controller, a not indexed continuous thumb controlled shifter cable controller, or indexed twist handle grips.

Shifter cable controller 49 moves shifter cable 84 in a direction so as to engage shifter cable assembly 184 with gear assembly 186 and input carrier assembly 188 to generate any one of the transmission ratios. More specifically, for a one-to-one transmission ratio, shifter cable 84 moves shifter ring 78 to lock the rotation of input carrier 94 to ring gear carrier assembly 90. This is preferably accomplished by shifter ring 78 locking tapered splines 132 on input carrier 94 to cogs 154 on ring gear carrier assembly 90. As ring gear caπier assembly 90 rotates, pawls 152 on ring gear carrier assembly 90 engage ratchet teeth 172 on ratchet shell cap 92 in one direction. Further, the rotation of ratchet shell cap 92 causes shell 72 to rotate output assembly 182.

For a transmission ratio of less than one-to-one, shifter cable 84 moves shifter ring 78 so as to retract retractable pawls 152 on ring gear carrier assembly 90. Tapered splines 132 of input carrier 94 remain engaged with cogs 154 of ring gear carrier assembly 90. Rotation of ring gear carrier assembly 90 is transferred to planetary gear carrier assembly 74. This is accomplished by engaging gear 156 on ring gear carrier assembly 90 to pinion gears 144 on ring gear carrier assembly 74. As planetary gear carrier assembly 74 rotates, pawls 140 on planetary gear carrier assembly 74 become engaged with ratchet teeth 172 on ratchet shell cap

92 in one direction.

For a transmission ratio of greater than one-to-one, shifter cable 84 moves shifter ring 78 so as to lock tapered splines 132 on input carrier 94 to lock with pinion pins 142 on planetary gear carrier assembly 74. Rotation is transferred from pinion gears 142 of planetary gear carrier assembly 74 to gear 156 of ring gear carrier assembly 90. Retractable pawls 152 of ring gear carrier assembly 90 engage ratchet teeth 172 of ratchet shell cap 92 in one direction.

Figs. 16A and 16B illustrate a second embodiment for the transmission system for transmission power from a helical drive to a drive wheel in a bicycle. Bicycle 500 in Figs. 16A and 16B is identical to bicycle 30 in Fig. 1, except for the structure for the transmission system. Instead of having in-line multi-gear assemblies coupled to the helical shafts of each helical drive, bicycle 500 in Figs. 16A and 16B employs a multi-gear hub 502 for varying the gear ratio between the output of the helical drive and the output of the transmission assembly. Multi- geared hub 502 can be used alone, as shown in Figs. 16A and 16B, or in combination with the in-line multi-gear transmission system discussed above. Details of multi-gear hub 502 and its method of operation are described below with reference to Figs. 17 and 18.

Multi-gear hub 502 includes a main shaft 504 that attaches to the bicycle frame. Bushings 506 and 508 are rotateably mounted onto each end of main shaft 504 and are prevented from moving in a lengthwise direction along the axis of main shaft 504 by nuts 510 and 512. Input gears 514 and 516 are rigidly attached to bushings 506 and 508 via nuts 509 and 511.

In the illustrated embodiment, input gears 514 and 516 are beveled so that the axis of rotation of input gears 514 and 516 is angled with respect to the axis of rotation of output gears 518 and 520 disposed at the ends of helical drive shafts 522 and 524 in helical drives 42. Input gears 514 and 516 in the multi-gear hub are coupled to output gears 518 and 520, respectively, so that the rotation of output gears 518 and 520 is transferred approximately 90° to input gears 514 and 516. It is to be understood, however, that input gears 514 and 516 and output gears 518 and 520 can have any of a variety of configurations that permit rotational motion to be transferred at an angle from an external input device to rotate bushings 506 and 508, such as using a worm gear or meshed sprockets.

Bushing 506 rotates and engages an overrunning clutch 526 which rotates an orbital shaft carrier 528. Rotation of orbital shaft carrier 528 rotates orbital shaft 530 around main shaft 504. Similarly, bushing 508 rotates and engages an overrunning clutch 532 which rotates orbital shaft carrier 528 to rotate orbital shaft 530 around main shaft 504. Rotational motion of either bushing 506 or bushing 508 translates into orbital movement of orbital shaft 530 via overrunning clutches 526 and/or 532. Thus, the overrunning clutches enable the input gears to be actuated independently of one another by an associated helical drive assembly.

Overrunning clutches 526 and 532 have a structure similar to the clutches used in helical drive 42. Although the clutches used in helical drive 42 are described in detail in the '982 application, overrunning clutches 526 and 532 used multi-gear hub 502 are described briefly below with reference to Fig. 18.

Overrunning clutch 526 or 532 includes a inner ring member 540 and an outer ring member 542. In the illustrated embodiment, inner ring member 540 has sloped shoulders 544 which wedge against rollers 546 when the inner ring member moves in a direction A with respect to the outer ring member, thereby engaging inner ring member 540 to outer ring member 542 so to both rotate together in direction A. When the inner ring member rotates in a direction opposite to A relative to the outer ring member, rollers 546 disengage from shoulders 544 and move into a receiving area 545 so that inner ring member 540 moves independent of outer ring member 542. It is to be understood that the shape, number and position of shoulders 544 can be varied so long as the wedging (engaging) and disengaging functions are achieved.

Multi-gear hub 502 includes a first stationary gear 550 and a second stationary gear 552 mounted on an intermediate portion of main shaft 504. A first orbital gear 554 and a second orbital gear 556 are rotateably mounted on orbital shaft 530 via bearings 555 and 557, respectively.

A cylindrical rotating member 558 serving as ring gear carrier rotates about main shaft 504 outside an orbit of orbital shaft 530. A first ring gear 560 and a second ring gear 562 are fixed to rotating member 558 via screws 564. The first and second ring gears are spaced apart from one another and from the inner walls as the ends of the rotating member by spacers 566.

First and second orbital gears are moveable along orbital shaft 530 to selectively engage first and second stationary gears 550 and 552, respectively. The stationary and ring gears are positioned such that if first orbital gear 554 is engaged with first stationary gear 550 and first ring gear 560, orbital rotation of orbital shaft 530 about main shaft 504 causes rotation in first orbital gear 550.

This rotation transfers to first ring gear 560 due to the engagement with first orbital gear 550, thereby rotating member 558 at a first transmission ratio. Similarly, if second orbital gear 556 is engaged with second stationary gear 552 and second ring gear 562, orbital rotation of orbital shaft 530 about main shaft 504 rotates second orbital gear 556. This rotation is transferred to second ring gear 562, thereby rotating member 558 at a second transmission ratio. The diameters of first stationary gear 550, said first orbital gear 554, and first ring gear 560 are different from the diameters of second stationary gear 552, second orbital gear 556, and second ring gear 562 so that the first transmission ratio is different from the second transmission ratio. A shifting mechanism 570 selectively and alternatively positions first orbital gear 554 in an engaged relationship with first stationary gear 550 and first ring gear 560 and positions second orbital gear 556 in an engaged relationship with second stationary gear 552 and second ring gear 562. Shifting mechanism 570 includes a bolt 572 slidably disposed in a hollow center of an intermediate portion of main shaft 504. In the illustrated embodiment, bolt 572 moves along a lengthwise direction of main shaft 504 between a first position and a second position. Bolt 572 includes an arm 574 that extends through a slot 576 defined along a lengthwise direction of main shaft 504. The first and second orbital gears 554 and 556 are coupled to arm 574 such that if bolt 572 is in the first position, first orbital gear 554 is engaged with first stationary gear 550 and first ring gear 560 and second orbital gear 556 is disengaged, and if bolt 572 is in the second position, second orbital gear 556 is engaged with second stationary gear 552 and second ring gear 562 and first orbital gear 554 is disengaged. When bolt 572 is in a position between the first and second position, first and second orbital gears 554 and 556 are not engaged with a ring gear, effectively placing the transmission system in neutral.

A spring 576 having one end attached to a spring nut 578 and another end attached to bolt 572 urges bolt 572 toward the end of main shaft 504 to which bushing 506 is coupled. A spring washer 580 maintains spring nut 578 in position within main shaft 504. A washer 582 acts as a stopper preventing movement of bolt 572 toward spring nut 578.

A chain 584 is attached to an end of bolt 572 opposite spring 576 via pin 586, nut 588 and washer 590. Shifting between the first transmission ratio and the second transmission ratio is accomplished by providing a tension on chain 584.

This tension moves bolt 572 within main shaft 504 under the bias applied by spring 576, thereby moving arm 574 and first and second orbital gears 554 and 556 between the first and second positions discussed above.

A gear shifting mechanism 585 (see Figs. 16A and 16B) controls the tension on chain 584, and, hence, the selection of the gear ratio for multi-gear hub 30. The gear shifting mechanism can be any conventional mechanism, for example indexed or continuous, and mounted on any suitable location on the bicycle.

In the illustrated embodiment, rotational movement of rotating member 558 is transferred to a hub casing 592 adapted to rotate about main shaft 504 outside rotating member 558. Bearings 594 between rotating member 558 and hub casing 592 permit rotational movement therebetween. An overrunning clutch 596, which has substantially the same configuration as overrunning clutches 526 and 532, couples hub casing 592 to rotating member 558 such that rotation of rotating member 558 in a first direction is transferred to hub casing 592 if rotating member

558 is rotating at a speed greater that of hub casing 592. If, however, rotating member 558 is rotating at a speed less that of hub casing 592, overrunning clutch 596 disengages, thereby decoupling hub casing 592 from rotating member 558. Spring washers 598 keep bearings 594 and overrunning clutch 596 in position. The rear wheel of the bicycle (not shown in Fig. 17) is coupled to hub casing 592 via spokes 600. In addition, a cover plate 602 is provided at each end of hub casing 592 and attached thereto via screws 604. Finally, lubrication holes 606 are provided in various portions of the multi-gear hub to provide lubrication to the surface of the components where friction is to be minimized. It is to be understood that the lubrication holes can be provided in a variety of locations and have shapes other than those illustrated in Fig. 17 so long a they serve to provide a lubricant, such as a lubricating oil, to the friction surfaces.

It is to be further understood that a wide variety of configurations for the arrangement of the helical drive system and the transmission system associated therewith are contemplated by the present invention in addition to those illustrated in Figs. 1, 2, 16 and 17. Some of these variations are discussed below with reference to Figs. 19-37.

Figs. 19-21 illustrate a bicycle 608 having a helical drive system 610 for transmitting input power to a drive wheel according to a third embodiment of the present invention. The bicycle illustrated in Figs. 19 and 20 is similar to the bicycle illustrated in Figs. 1 and 2, except that a different configuration for the helical drive system is employed.

In this embodiment, helical drive system 610 includes a pair of helical drives 612a and 612b that are aligned with one another along a plane generally perpendicular to the longitudinal axis of bicycle 608. The helical drives are arranged such that input devices (pedals) 614 are disposed in generally the same location as the pedals in a conventional bicycle. Therefore, the configuration for bicycle 608 in Figs. 19 and 20 is more familiar to the general public than the configuration illustrated in Figs. 1 and 2. In the embodiment illustrated in Figs. 19-21, gears 611 and 613 are provided at the end of respective helical drive shafts 616a and 616b. Gears 611 and 613 are meshed so that helical drives 612a and 612b operate in synchronization with one another. A transmission system 615 couples the output of helical shafts 616a and 616b to rear wheel hub 618. Transmission system 615 includes a pair of in-line multi-gear assemblies 620a and 620b coupled to helical shafts 616a and 616b for changing the transmission ratio thereof.

A gear assembly 622 couples the output rotational motion output from helical shafts 616a and 616b to a single drive shaft 623. The gears in gear assembly 622 are selectively engageable with one another to merit engaging and disengaging of the transmission system. In the illustrated embodiment, a cable

615 causes a gear 619 to move in and out of engagement with the other gears in gear assembly 622. The gears in gear assembly 622 are coupled to the gears 611 and 613 via an overrunning clutch, as illustrated in Fig. 18, to permit the bicycle to freewheel. A bevel gear 624 at the rearward end of drive shaft and a bevel gear 626 on hub 618 transfers rotational energy to rear wheel 36 of bicycle 608.

Fig. 21 is a schematic illustration of the helical drive and transmission systems showing the various components all in a same plane for ease of illustration.

Figs. 22-23 illustrate a bicycle 708 having a helical drive system 710 for transmitting input power to a drive wheel according to a forth embodiment of the present invention. The bicycle illustrated Fig. 22 is similar to the bicycle illustrated in Figs. 19 and 20, except that helical drive system 710 includes two drive shafts 712 and 714 for transmitting rotational motion to the rear wheel hub, rather than one drive shaft as in the embodiment depicted in Figs. 19 and 20.

In the embodiment illustrated in Fig. 22, a transmission system 716 couples the output of helical shafts 718a and 718b to a hub 719 of a rear wheel 720.

Transmission system 716 includes a pair of in-line multi-gear assemblies 722a and 722b coupled to helical shafts 718a and 718b, respectively, for changing the transmission ratio thereof. Each of in-line multi-gear assemblies 722a and 722b couples to one of drive shafts 712 and 714. A synchronization gear 724 selectively meshes with gears 726 and 727 provided at the output of the helical drive assemblies. When meshed, the synchronization gear causes the helical drive assemblies to operate in a synchronized manner. Other components are substantially identical to the helical drive system depicted in Figs. 19 and 20.

Fig. 24 illustrates a poly-cycle 808 having a helical drive system 810 for transmitting input power to a pair of driven wheels 812a and 812b according to a fifth embodiment of the present invention. The poly-cycle illustrated Fig. 24 is similar to the bicycle illustrated in Figs. 19 and 20, except that two rear wheels 812a and 812b are employed in this embodiment.

In the embodiment illustrated in Fig. 24, a drive shaft 814 couples with a pair of hub shafts 816a and 816b extending from the hubs (not shown) of rear wheels 812a and 812b. As shown in Fig. 24, a gear assembly 820 couples the output of the helical drives to drive shaft 814. The components in the transmission system of this embodiment are substantially identical to the helical drive system depicted in Figs. 19-23. Figs. 26-29 illustrate a polycycle 908 having a helical drive system 910 for transmitting input power to a pair of drive wheels 912a and 912b according to a sixth embodiment of the present invention. The poly-cycle illustrated Figs. 26 and 27 is similar to the poly-cycle illustrated in Fig. 24, except that this embodiment includes a pair of helical drive assemblies 914a and 914b that are aligned with one another along a plane generally parallel to the longitudinal axis of poly-cycle 908. This configuration reduces the overall width of the helical drive system.

Helical drive assemblies 914a and 914b are structurally similar to those discussed above in the previous embodiments and include in-line multi-gear transmission assemblies 916a and 916b coupled to helical shafts. In addition, the configuration for gear assembly 920 that transfers rotational motion from the helical drive assemblies to the rear wheel is fundamentally the same as the helical drive assemblies of the prior embodiments. The primary different between this embodiment and previous embodiments is the placement and orientation of drive shaft 922 relative to gear assembly 920 due to the alignment of the helical drive assemblies 914a and 914b along the centerline of the bicycle. Other components of the helical drive and transmission systems are substantially identical to the helical drive system depicted in Fig. 24.

Figs. 30 and 31 illustrate a bicycle 1008 having a helical drive system 1010 for transmitting input power to a drive wheel according to a seventh embodiment of the present invention. The bicycle illustrated Figs. 30 and 31 is similar to the bicycle illustrated in Figs. 22, except that this embodiment includes a pair of helical drives 1012a and 1012b that are aligned with one another along a plane generally parallel to the longitudinal axis of bicycle 1008, as the embodiment illustrated in Figs. 26 and 27. In addition, a pair of drive shafts 1014a and 1014b are coupled to a gear assembly 1016 having a configuration similar to that illustrated in Figs. 26-29. Other components are substantially identical to the helical drive system depicted in Fig. 22.

Figs. 33 and 34 illustrate a bicycle 1108 having a helical drive system 1110 for transmitting input power to a drive wheel according to an eighth embodiment of the present invention. The bicycle illustrated Figs. 33 and 34 is similar to the bicycle illustrated in Figs. 30 and 31, except that this embodiment includes one drive shaft 11 12 rather than two. Other components are substantially identical to the helical drive system depicted in Figs. 30 and 31. Finally, Fig. 37 illustrates a tandem polycycle 1208 having a pair of helical drive systems 1210a and 1210b for transmitting input power to a pair of drive wheels 1212a and 1212b according to a ninth embodiment of the present invention. Polycycle 1208 includes in-line multi-gear assemblies 1214, 1216, 1218 and 1220 associated with each helical drive shaft and a multi-gear hubs 1222 and

1224 associated with each helical drive system 1201a and 1210b. Other components of polycycle 1208 are substantially the same as those illustrated in the previous embodiments.

While the presently preferred embodiments of the present invention are depicted in the illustrations and discussed above, it is to be understood that a number of variations on the helical drive transmission system employing the inline multi-gear assembly and/or the multi-gear wheel hub are contemplated by the present invention. For example, more than one in-line multi-gear transmission assemblies can be employed in the transmission system. The in-line multi-gear transmission assemblies can be provided at locations in the transmission system other than directly coupled to the helical shaft. For example, an in-line multi-gear transmission assembly can be provided along the drive shaft. Of course, the number of transmission ratios and the use of both an in-line multi-gear transmission assembly and a multi-gear hub in the same machine are also possible. It thus will be seen that the objects of this invention have been fully and effectively accomplished. It will be realized, however, that the foregoing preferred specific embodiment has been shown and described for the purpose of this invention and is subject to change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.

A helical drive bicycle may be made with both in-line transmissions as in Fig. 1, and a multi-gear hub, as in Fig. 16B. Also, a bicycle can be made with more than one in-line transmission in series, (for example, one attached to a drive shaft, and one attached to the helical member). Any such serial dual transmission bike would then offer a multiplied range of gear ratios. For example, a two speed in-line transmission with a five speed hub transmission, would yield a 10 speed bike, and could simulate the gears available on a conventional 10 speed bike with derailleurs, sprockets, and a chain.

A three speed in-line transmission and a two speed hub transmission are shown here. Other embodiments, could have other numbers of speeds, either more or less.

If a single drive shaft, as in Figs. 19, 20, and 21, is used, then a conventional multi-gear hub with a single input gear can be used, either with or without an in-line transmission. Braking of these bicycles are by conventional hand brake mechanisms.

Sprint bike embodiments may have no brakes.

The bike embodiments of the present invention can also be made with helical drives that are not integrated into the frame but attached to the exterior of the frame. The multi-gear hub is shown with two input gears, one on each end of the hub. Instead of these dual input gears other dual input devices, such as sprockets, can be used where appropriate, one on each end of the hub. Also, here pinion gears are shown with the hub and drive shaft, but other gear arrangements between hub and drive shaft can be used, such as a worm gear.

Claims

WHAT IS CLAIMED IS:

1. A helical drive system comprising: a first helical drive having an input portion and an output portion; a first input device operatively coupled to said input portion of said first helical drive such that actuation of said first input device rotates said output portion of said first helical drive; and a transmission system having an input portion and an output portion, said input portion of said transmission system being operatively coupled to said output portion of said first helical drive, said transmission system having a selectively variable transmission ratio to provide a range of alternative transmission ratios for transferring rotational motion between said input portion and said output portion of said transmission system.

2. A helical drive system according to claim 1, wherein said transmission system comprises an in-line multi-gear assembly comprising: an input carrier assembly operatively coupled to said output portion of said first helical drive such that an axis of rotation of said input carrier assembly is substantially aligned with an axis of rotation of said output portion of said first helical drive; a gear assembly coupled to said input carrier assembly, said gear assembly having a plurality of gears selectively engageable in various combinations to provide said selectively variable transmission ratio; and an output assembly coupled to said gear assembly.

3. A helical drive system according to claim 2, wherein said plurality of gears include: a ratchet shell cap having a cylindrical shape with a hollow center defined therein, said ratchet shell cap being rotateably connected to said output assembly; a ring gear carrier assembly having a cylindrical shape with a hollow portion defined therein, said ring gear carrier being concentrically located inside said ratchet shell cap; and a planetary gear carrier assembly having a cylindrical shape with a hollow center portion defined therein, said planetary gear carrier being concentrically located inside said ring gear carrier; wherein said input carrier assembly, said ring gear carrier assembly and said ratchet shell cap are adapted to be rotateably engaged such that a rotation of said input carrier assembly induces a rotation of said output assembly at a first transmission ratio; wherein said input carrier assembly, said ring gear carrier assembly, said planetary gear carrier assembly and output assembly are adapted to be rotateably engaged such that a rotation of said input carrier assembly induces said rotation of said output assembly at a second transmission ratio; and wherein said input carrier assembly, said planetary gear carrier assembly, said ring gear carrier assembly and said ratchet shell cap are adapted to be rotateably engaged such that said rotation of said input carrier assembly induces a rotation of said output assembly at a third transmission ratio.

4. A helical drive system according to claim 3, said input carrier assembly further comprising: a retaining nut having a hollow center defined therein; an input carrier having a cylindrical shape with a hollow center defined therein to receive said retaining nut, a helical drive locking surface to lock with said helical drive, and a plurality of tapered splines protruding from a gear assembly locking surface.

5. A helical drive system according to claim 4, wherein: said ratchet shell cap includes a plurality of ratchet shell cap teeth disposed on said inner surface of said ratchet shell cap; said ring gear carrier assembly includes a plurality of cogs disposed on an input carrier locking inner surface, a plurality of retractable pawls pivotally mounted on said ring gear carrier and a gear disposed on a planetary gear carrier locking inner surface; said planetary gear carrier assembly includes a plurality of planetary pinion gears, a plurality of pawls pivotally mounted, and a plurality of carrier pins protruding from an input carrier locking surface; said output assembly includes an output gear and a shell operatively connected to said ratchet shell cap; at least one of said tapered splines of said input carrier is selectively engageable to at least one of said cogs of said ring gear carrier assembly and said carrier pins of said planetary gear carrier assembly; at least one of said ratchet shell cap teeth is selectively engageable to at least one of said retractable pawls of said ring gear carrier assembly and said pawls of planetary gear carrier assembly; and said gear of said ring gear carrier assembly is selectively engageable to at least one of said planetary pinion gears of said planetary gear carrier assembly.

6. A helical drive system according to claim 2, wherein said first helical drive comprises: a helical shaft, and an helical carrier assembly operatively coupled with to an end portion of said helical shaft; and said in-line multi-gear assembly comprises: an axle assembly having a shifter slot arrangement defined therein and an end operatively connected to said input carrier assembly, wherein said input carrier assembly, said gear assembly and said output assembly are mounted coaxially on said axle assembly; a shifter cable assembly having a shifter mechanism and a shifter cable, said shifter mechanism being arranged inside said shifter slot arrangement of said axle assembly and mounted coaxially on said shifter cable, and said shifter mechanism interacting with said plurality of gears of said gear assembly to select one of said first, said second and said third transmission ratios, wherein said shifter cable extends from said shifter mechanism through said input carrier assembly, said helical drive and said helical carrier assembly; and a helical drive housing having cylindrical shape with a hollow center, a slot defined in a longitudinal direction on said helical drive, wherein said slot receives at least a portion of said first input device; an end plate attached to said output end of said helical drive housing, wherein said helical drive housing houses said axle assembly, said gear assembly, said shifter cable assembly, said input carrier assembly, said helical drive and said helical carrier assembly.

7. A helical drive system according to claim 6, wherein said helical shaft is a twisted shaft operatively coupled to said first input device and operatively connected to said input carrier assembly and said helical carrier assembly.

8. A helical drive system according to claim 6, wherein said shifter mechanism includes a shifter ring having an outer surface and a spring, said shifter ring includes a plurality of protruding parts disposed on said outer surface, wherein said shifter ring and said spring are coaxially mounted on a bushing end of said shifter cable.

9. A helical drive system according to claim 1, wherein said transmission system comprises a multi-gear hub assembly comprising: a first input gear operatively coupled to said output portion of said first helical drive such that an axis of rotation of said first input gear is at a first angle relative to an axis of rotation of said output portion of said first helical drive, said first angle being greater than zero degrees; and a gear assembly having a first input portion, which is operatively coupled to said first input gear, an output portion, and a plurality of gears which, in an engaged position, transfer rotational energy from said first input portion to said output portion of said gear assembly, said plurality of gears being selectively engageable in various combinations so as to provide said range of alternative transmission ratios between said first input portion and said output portion of said gear assembly.

10. A helical drive system according to claim 9, further comprising: a second helical drive having an input portion and an output portion; and a second input device operatively coupled to said input portion of said second helical drive such that actuation of said second input device rotates said output portion of said second helical drive; and wherein said multi-gear hub assembly further comprises: a second input gear operatively coupled to said output portion of said second helical drive such that an axis of rotation of said second input gear is at a second angle relative to an axis of rotation of said output portion of said second helical drive, said second angle being greater than zero degrees, and wherein said gear assembly includes a second input portion operatively coupled to said second input gear, said plurality of gears in a said engaged position transferring rotational energy from at least one of said first and said second input portions to said output portion of said gear assembly, said plurality of gears being selectively engageable in various combinations to provide said selectable alternative range of transmission ratios between at least one of said first and said second input portions of said gear assembly and said output portion of said gear assembly.

11. A helical drive system according to claim 9, wherein said gear assembly comprises: a main shaft having end portions and an intermediate portion; a first bushing rotateably mounted on said end portion of said main shaft, said first input gear being fixed to said first bushing, wherein rotation of said first input gear by said output portion of said first helical drive is transferred to said first bushing; an orbital shaft having a first end operatively coupled to said first bushing such that rotation of said first bushing causes said orbital shaft to orbit said main shaft, said orbital shaft having an end portion coupled to said bushing and an intermediate portion; a rotating member adapted to rotate about said main shaft outside an orbit of said orbital shaft; a first stationary gear mounted on said main shaft at said intermediate portion thereof; a first orbital gear rotateably mounted on said orbital shaft at said intermediate portion thereof; a first ring gear mounted on said rotating member; a second stationary gear mounted on said main shaft also at said intermediate portion thereof proximate to said first stationary gear; a second orbital gear mounted on said orbital shaft at said intermediate portion thereof proximate to said first orbital gear; a second ring gear mounted on said rotating member; and a shifting mechanism that selectively and alternatively positions said first orbital gear in an engaged relationship with said first stationary gear and said first ring gear and said second orbital gear in an engaged relationship with said second stationary gear and said second ring gear, wherein, if said first orbital gear is in said engaged relationship with said first stationary gear and said first ring gear, orbital rotation of said orbital shaft about said main shaft induces a rotation in said first orbital gear that is transferred to said first ring gear, thereby rotating said rotating member at a first transmission ratio, wherein, if said second orbital gear is in said engaged relationship with said second stationary gear and second first ring gear, orbital rotation of said orbital shaft about said main shaft induces a rotation in said second orbital gear that is transferred to said second ring gear, thereby rotating said rotating member at a second transmission ratio, and wherein diameters of said first stationary gear, said first orbital gear, and said first ring gear are different from diameters of said second stationary gear, said second orbital gear, and said second ring gear so that said first transmission ratio is different from said second transmission ratio.

12. A helical drive system according to claim 11, wherein said orbital shaft is operatively coupled to said first bushing through an overrunning clutch.

13. A helical drive system according to claim 11, wherein said shifting mechanism comprises a bolt slidable disposed in a hollow center of said intermediate portion of said main shaft, said bolt being movable along a lengthwise direction of said main shaft between a first position and a second position, said bolt having an arm that extends from said main shaft through a slot defined along a lengthwise direction of said main shaft, said first and said second orbital gears being operatively coupled to said arm such that if said bolt is in said first position, said first orbital gear is in said engaged relationship with said first stationary gear and said first ring gear and said second orbital gear is disengaged, and if said bolt is in said second position, said second orbital gear is in said engaged relationship with said second stationary gear and said second ring gear and said first orbital gear is disengaged.

14. A helical drive system according to claim 11, further comprising: a hub casing adapted to rotate about said main shaft outside said rotating member; and an overrunning clutch coupling said hub casing to said rotating member such that rotation of said rotating member in a first direction is transferred to said hub casing via said clutch, an if said rotating member is rotating at a velocity less that of said hub casing, said overrunning clutch disengages said hub casing from said rotating member.

15. A helical drive system according to claim 11, further comprising: a first overrunning clutch disposed between a first end of said orbital shaft and said first bushing; a second helical drive having an input portion and an output portion; and a second input device operatively coupled to said input portion of said second helical drive such that actuation of said second input device rotates said output portion of said second helical drive; a second bushing rotateably mounted on an other end portion of said main shaft; a second input gear operatively coupled to said output portion of said second helical drive such that an axis of rotation of said second input gear is at a second angle relative to an axis of rotation of said output portion of said second helical drive, said second angle being greater than zero degrees, said second input gear being fixed to said second bushing such that rotation of said second input gear by said output portion of said second helical drive is transferred to said second bushing through said second angle, a second end of said orbital shaft being operatively coupled to said second bushing such that rotation of said second bushing causes said orbital shaft to orbit said main shaft; and a second overrunning clutch disposed between said second end of said orbital shaft and said second bushing, said first and said second overrunning clutches enabling said first and said second hub bevel gears to be actuated independently of one another by said respective first and second helical drives.

16. A helical drive system according to claim 15, wherein said shifting mechanism comprises a bolt slidable disposed in a hollow center of said intermediate portion of said main shaft, said bolt being movable along a lengthwise direction of said main shaft between a first position and a second position, said bolt having an arm that extends from said main shaft through a slot defined along a lengthwise direction of said main shaft, said first and said second orbital gears being operatively coupled to said arm such that if said bolt is in said first position, said first orbital gear is in said engaged relationship with said first stationary gear and said first ring gear and said second orbital gear is disengaged, and if said bolt is in said second position, said second orbital gear is in said engaged relationship with said second stationary gear and said second ring gear and said first orbital gear is disengaged.

17. A helical drive system according to claim 16, further comprising: a hub casing adapted to rotate about said main shaft outside said rotating member; and an overrunning clutch coupling said hub casing to said rotating member such that rotation of said rotating member in a first direction is transferred to said hub casing via said clutch, an if said rotating member is rotating at a velocity less that of said hub casing, said overrunning clutch disengages said hub casing from said rotating member.

18. A helical drive system according to claim 1, wherein said transmission system comprises: a first in-line multi-gear assembly comprising: an input carrier assembly operatively coupled to said output portion of said first helical drive such that an axis of rotation of said input carrier assembly is substantially aligned with an axis of rotation of said output portion of said first helical drive; a first gear assembly coupled to said input carrier assembly, said first gear assembly having a plurality of gears selectively engageable in various combinations to provide said selectively variable transmission ratio; and an output assembly coupled to said first gear assembly; and a multi-gear hub assembly comprising: a first input gear operatively coupled to said output portion of said first helical drive such that an axis of rotation of said first input gear is at a first angle relative to an axis of rotation of said output portion of said first helical drive, said first angle being greater than zero degrees; and a second gear assembly having a first input portion, which is operatively coupled to said first input gear, an output portion, and a plurality of gears which, in an engaged position, transfer rotational energy from said first input portion to said output portion of said gear assembly, said plurality of gears being selectively engageable in various combinations so as to provide said range of alternative transmission ratios between said first input portion and said output portion of said gear assembly.

19. A helical drive system according to claim 18, wherein said plurality of gears in said first gear assembly of said in-line multi-gear assembly includes: a ratchet shell cap having a cylindrical shape with a hollow center, said ratchet shell cap being rotateably connected to said output assembly; a ring gear carrier assembly having a cylindrical shape with a hollow portion defined therein, said ring gear carrier being concentrically located inside said ratchet shell cap; and a planetary gear carrier assembly having a cylindrical shape with a hollow center portion defined therein, said planetary gear carrier being concentrically located inside said ring gear carrier; wherein said input carrier assembly, said ring gear carrier assembly and said ratchet shell cap are adapted to be rotateably engaged such that a rotation of said input carrier assembly induces a rotation of said output assembly at a first transmission ratio; wherein said input carrier assembly, said ring gear carrier assembly, said planetary gear carrier assembly and output assembly are adapted to be rotateably engaged such that a rotation of said input carrier assembly induces said rotation of said output assembly at a second transmission ratio; and wherein said input carrier assembly, said planetary gear carrier assembly, said ring gear carrier assembly and said ratchet shell cap are adapted to be rotateably engaged such that said rotation of said input carrier assembly induces a rotation of said output assembly at a third transmission ratio; and wherein said second gear assembly in said multi-gear hub comprises: a main shaft having end portions and an intermediate portion; a first bushing rotateably mounted on said end portion of said main shaft, said first input gear being fixed to said first bushing, wherein rotation of said first input gear by said output portion of said first helical drive is transferred to said first bushing; an orbital shaft having a first end operatively coupled to said first bushing such that rotation of said first bushing causes said orbital shaft to orbit said main shaft, said orbital shaft having an end portion coupled to said bushing and an intermediate portion; a rotating member adapted to rotate about said main shaft outside an orbit of said orbital shaft; a first stationary gear mounted on said main shaft at said intermediate portion thereof; a first orbital gear rotateably mounted on said orbital shaft at said intermediate portion thereof; a first ring gear mounted on said rotating member; a second stationary gear mounted on said main shaft also at said intermediate portion thereof proximate to said first stationary gear; a second orbital gear mounted on said orbital shaft at said intermediate portion thereof proximate to said first orbital gear; a second ring gear mounted on said rotating member; and a shifting mechanism that selectively and alternatively positions said first orbital gear in an engaged relationship with said first stationary gear and said first ring gear and said second orbital gear in an engaged relationship with said second stationary gear and said second ring gear, wherein said first orbital gear is adapted to engage said first stationary gear and said first ring gear such that orbital rotation of said orbital shaft about said main shaft induces a rotation in said first orbital gear that is transferred to said first ring gear, thereby rotating said rotating member at a first -transmission ratio, wherein said second orbital gear is adapted to engage said second stationary gear and second first ring gear such that orbital rotation of said orbital shaft about said main shaft induces a rotation in said second orbital gear that is transferred to said second ring gear, thereby rotating said rotating member at a second transmission ratio, and wherein diameters of said first stationary gear, said first orbital gear, and said first ring gear are different from diameters of said second stationary gear, said second orbital gear, and said second ring gear so that said first transmission ratio is different from said second transmission ratio.

20. A helical drive system according to claim 18, further comprising: a second helical drive having an input portion and an output portion; and a second input device operatively coupled to said input portion of said second helical drive such that actuation of said second input device rotates said output portion of said second helical drive; and said transmission system further comprises a second in-line multi-gear assembly comprising: a second input carrier assembly operatively coupled to said output portion of said second helical drive such that an axis of rotation of said second input carrier assembly is substantially aligned with an axis of rotation of said output portion of said second helical drive; a third gear assembly coupled to said second input carrier assembly, said third gear assembly having a plurality of gears selectively engageable in various combinations to provide said selectively variable transmission ratio; and a second output assembly coupled to said third gear assembly; and wherein said multi-gear hub assembly further comprises: a second input gear operatively coupled to said output portion of said second helical drive such that an axis of rotation of said second input gear is at a second angle relative to an axis of rotation of said output portion of said second helical drive, said second angle being greater than zero degrees, and wherein said second gear assembly includes a second input portion operatively coupled to said second input gear, said plurality of gears in a said engaged position transferring rotational energy from at least one of said first and said second input portions to said output portion of said gear assembly, said plurality of gears being selectively engageable in various combinations to provide said selectable alternative range of transmission ratios between at least one of said first and said second input portions of said gear assembly and said output portion of said gear assembly.

21. A helical drive transmission system according to claim 1, wherein said transmission system comprises: a first power train system coupling said output of said first helical drive to a driven member; a first in-line multi-gear assembly comprising: an input carrier assembly disposed at a first portion of said power train system such that an axis of rotation of said input carrier assembly is substantially aligned with an axis of rotation of a portion of said power train system adjacent thereto; and a first gear assembly coupled to said input carrier assembly, said first gear assembly having a plurality of gears selectively engageable in various combinations to provide said selectively variable transmission ratio; and a first output assembly coupled to said first gear assembly; and a multi-gear hub assembly comprising: a first input gear disposed in a second portion of said power train system such that an axis of rotation of said first input gear is at a first angle relative to an axis of rotation of a portion of said power train system adjacent thereto, said first angle being greater than zero degrees; and a second gear assembly having a first input portion, which is operatively coupled to said first input gear, an output portion, and a plurality of gears which, in an engaged position, transfer rotational energy from said first input portion to said output portion of said gear assembly, said plurality of gears being selectively engageable in various combinations so as to provide said range of alternative transmission ratios between said first input portion and said output portion of said gear assembly.

22. A helical drive transmission system according to claim 21, wherein said first helical drive incudes a helical drive shaft and wherein in-line multi-gear assembly is operatively coupled to said output portion of said first helical drive such that said in-line multi-gear assembly is adjacent said helical drive shaft, said power train system comprising: a gear system that alters a direction of rotational motion output from in-line multi-gear assembly from a first direction to a second direction; and a drive shaft having a first end coupled to an output of said gear system and a second end coupled to said multi-gear hub.

23. A helical drive transmission system according to claim 21, further comprising a second helical drive having an input portion and an output portion; and a second input device operatively coupled to said input portion of said second helical drive such that actuation of said second input device rotates said output portion of said second helical drive; wherein said transmission system further comprises: a second power train system coupling said output of said second helical drive to said driven member; a second in-line multi-gear assembly comprising: an input carrier assembly disposed at a first portion of said second power train system such that an axis of rotation of said input carrier assembly is substantially aligned with an axis of rotation of a portion of said power train system adjacent thereto; and a first gear assembly coupled to said input carrier assembly, said first gear assembly having a plurality of gears selectively engageable in various combinations to provide said selectively variable transmission ratio; and an output assembly coupled to said first gear assembly; and said multi-gear hub assembly further comprising: a second input gear disposed in a third portion of said power train system such that an axis of rotation of said second input gear is at a second angle relative to an axis of rotation of a portion of said power train system adjacent thereto, said second angle being greater than zero degrees, said second input gear being operatively coupled to said second gear assembly in said multi-gear hub.

24. A helical drive transmission system according to claim 23, wherein first helical drive includes a first helical drive shaft and said first in-line multi-gear assembly is operatively coupled to said output portion of said first helical drive such that said first in-line multi-gear assembly is adjacent to an end of said first helical drive shaft and wherein said second helical drive includes a second helical drive shaft and said second in-line multi-gear assembly is operatively coupled to said output portion of said second helical drive such that said second in-line multi- gear assembly is adjacent to an end of said second helical drive shaft, said first and said second power train systems together include: a gear system that alters a direction of rotational motion output from first and said second in-line multi-gear assemblies from a first direction to a second direction; and a first drive shaft having a first end coupled to an output of said gear system and a second end coupled to said first input gear of said multi-gear hub.

25. A helical drive transmission system according to claim 24, wherein said first and said second power train system together further include a second drive shaft having a first end coupled to an output of said gear system and a second end coupled to said second input gear of said multi-gear hub.

26. An in-line multi-gear assembly comprising: an input carrier assembly having a helical drive locking surface adapted to operatively couple to an output portion of a helical drive; a gear assembly coupled to said input carrier assembly, said gear assembly having a plurality of gears selectively engageable in various combinations to provide said selectively variable transmission ratio; and an output assembly coupled to said gear assembly.

27. An in-line gear assembly according to claim 26, wherein said plurality of gears comprise: a ratchet shell cap having a cylindrical shape with a hollow center defined therein, said ratchet shell cap being rotateably connected to said output assembly; a ring gear carrier assembly having a cylindrical shape with a hollow portion defined therein, said ring gear carrier being concentrically located inside said ratchet shell cap; and a planetary gear carrier assembly having a cylindrical shape with a hollow center portion defined therein, said planetary gear carrier being concentrically located inside said ring gear carrier; wherein said input carrier assembly, said ring gear carrier assembly and said ratchet shell cap are adapted to be rotateably engaged such that a rotation of said input assembly induces a rotation of said output assembly at a first transmission ratio; wherein said input carrier assembly, said ring gear carrier assembly, said planetary gear carrier assembly and output assembly are adapted to be rotateably engaged such that a rotation of said input assembly induces a rotation of said output assembly at a second transmission ratio; and wherein said input carrier assembly, said planetary gear carrier assembly, said ring gear carrier assembly and said ratchet shell cap are adapted to be rotateably engaged such that a rotation of said input assembly induces a rotation of said output assembly at a third transmission ratio.

28. An in-line gear assembly according to claim 27, said input carrier assembly further comprising: a retaining nut having a hollow center defined therein; an input carrier having a cylindrical shape with a hollow center defined therein to receive said retaining nut, a helical drive locking surface to lock with said helical drive, and a plurality of tapered splines protruding from a gear assembly locking surface.

29. An in-line gear assembly according to claim 28, wherein: said ratchet shell cap includes a plurality of ratchet shell cap teeth disposed on said inner surface of said ratchet shell cap; said ring gear carrier assembly includes a plurality of cogs disposed on an input carrier locking inner surface, a plurality of retractable pawls pivotally mounted on said ring gear carrier and a gear disposed on a planetary gear carrier locking inner surface; said planetary gear carrier assembly includes a plurality of planetary pinion gears, a plurality of pawls pivotally mounted, and a plurality of carrier pins protruding from an input carrier locking surface; said output assembly includes an output gear and a shell operatively connected to said ratchet shell cap; at least one of said tapered splines of said input carrier is selectively engageable to at least one of said cogs of said ring gear carrier assembly and said carrier pins of said planetary gear carrier assembly; at least one of said ratchet shell cap teeth is selectively engageable to at least one of said retractable pawls of said ring gear carrier assembly and said pawls of planetary gear carrier assembly; and said gear of said ring gear carrier assembly is selectively engageable to at least one of said planetary pinion gears of said planetary gear carrier assembly.

30. An in-line gear assembly according to claim 29, further comprising: an axle assembly having a shifter slot arrangement defined therein and an end operatively connected to said input carrier assembly, wherein said input carrier assembly, said gear assembly and said output assembly are mounted coaxially on said axle assembly; and a shifter cable assembly having a shifter mechanism and a shifter cable, said shifter mechanism being arranged inside said shifter slot arrangement of said axle assembly and mounted coaxially on said shifter cable, and said shifter mechanism interacting with said plurality of gears of said gear assembly to select one of said first, said second and said third transmission ratios, wherein said shifter cable runs from said shifter mechanism through said input carrier assembly.

31. An in-line gear assembly according to claim 30, said shifter mechanism includes a shifter ring with an outer surface and a spring, said shifter ring having a plurality of protruding parts disposed on said outer surface, said shifter ring and said spring being coaxially mounted on a bushing end of said shifter cable.

32. A multi-gear hub assembly comprising: a main shaft having end portions and an intermediate portion; a first bushing rotateably mounted on said end portion of said main shaft; a first input gear fixed to said first bushing, wherein an axis of rotation of said first input gear is at a first angle with respect to an axis of rotation of a first external input so that a rotation of said first external input is transferred from said first external input to said first bushing through said first angle; an orbital shaft having a first end operatively coupled to said first bushing such that rotation of said first bushing causes said orbital shaft to orbit said main shaft, said orbital shaft having an end portion coupled to said bushing and an intermediate portion; a rotating member adapted to rotate about said main shaft outside an orbit of said orbital shaft; a first stationary gear mounted on said main shaft at said intermediate portion thereof; a first orbital gear rotateably mounted on said orbital shaft at said intermediate portion thereof; a first ring gear mounted on said rotating member; a second stationary gear mounted on said main shaft also at said intermediate portion thereof proximate to said first stationary gear; a second orbital gear mounted on said orbital shaft at said intermediate portion thereof proximate to said first orbital gear; a second ring gear mounted on said rotating member; and a shifting mechanism that selectively and alternatively positions said first orbital gear in an engaged relationship with said first stationary gear and said first ring gear and said second orbital gear in an engaged relationship with said second stationary gear and said second ring gear, wherein said first orbital gear is adapted to engage said first stationary gear and said first ring gear such that orbital rotation of said orbital shaft about said main shaft induces a rotation in said first orbital gear that is transferred to said first ring gear, thereby rotating said rotating member at a first transmission ratio, wherein said second orbital gear is adapted to engage said second stationary gear and second first ring gear such that orbital rotation of said orbital shaft about said main shaft induces a rotation in said second orbital gear that is transfe╧Çed to said second ring gear, thereby rotating said rotating member at a second transmission ratio, and wherein diameters of said first stationary gear, said first orbital gear, and said first ring gear are different from diameters of said respective second stationary gear, said second orbital gear, and said second ring gear so that said first. transmission ratio is different from said second transmission ratio.

33. A multi-gear hub assembly according to claim 32, wherein said orbital shaft is operatively coupled to said bushing through an overrunning clutch.

34. A multi-gear hub assembly according to claim 32, wherein said shifting mechanism comprises a bolt slidable disposed in a hollow center of said intermediate portion of said main shaft, said bolt being movable along a lengthwise direction of said main shaft between a first position and a second position, said bolt having an arm that extends from said main shaft through a slot defined along a lengthwise direction of said main shaft, said first and said second orbital gears being operatively coupled to said arm such that if said bolt is in said first position, said first orbital gear is in said engaged relationship with said first stationary gear and said first ring gear and said second orbital gear is disengaged, and if said bolt is in said second position, said second orbital gear is in said engaged relationship with said second stationary gear and said second ring gear and said first orbital gear is disengaged.

35. A multi-gear hub assembly according to claim 32, further comprising: a hub casing adapted to rotate about said main shaft outside said rotating member; and an overrunning clutch coupling said hub casing to said rotating member such that rotation of said rotating member in a first direction is transferred to said hub casing via said clutch, an if said rotating member is rotating at a velocity less that of said hub casing, said overrunning clutch disengages said hub casing from said rotating member.

36. A multi-gear hub assembly according to claim 32, further comprising: a first overrunning clutch disposed between a first end of said orbital shaft and said first bushing; a second bushing fixed rotateably mounted on an other end portion of said main shaft; a second input gear fixed to said second bushing, wherein an axis of rotation of said second input gear is at a second angle with respect to an axis of rotation of a second external input so that a rotation of said second external input is transferred from said second external input to said second bushing through said second angle, a second end of said orbital shaft being operatively coupled to said second bushing such that rotation of said second bushing causes said orbital shaft to orbit said main shaft; and a second overrunning clutch disposed between said second end of said orbital shaft and said second bushing, said first and said second overrunning clutches enabling said first and said second hub bevel gears to be actuated independently of one another.

37. A multi-gear hub assembly according to claim 36, wherein said first external input is a first helical drive and said second external input is a second helical drive.

38. A multi-gear hub assembly according to claim 37, wherein said shifting mechanism comprises a bolt slidable disposed in a hollow center of said intermediate portion of said main shaft, said bolt being movable along a lengthwise direction of said main shaft between a first position and a second position, said bolt having an arm that extends from said main shaft through a slot defined along a lengthwise direction of said main shaft, said first and said second orbital gears being operatively coupled to said arm such that if said bolt is in said first position, said first orbital gear is in said engaged relationship with said first stationary gear and said first ring gear and said second orbital gear is disengaged, and if said bolt is in said second position, said second orbital gear is in said engaged relationship with said second stationary gear and said second ring gear and said first orbital gear is disengaged.

39. A multi-gear hub assembly according to claim 38, further comprising: a hub casing adapted to rotate about said main shaft outside said rotating member; and an overrunning clutch coupling said hub casing to said rotating member such that rotation of said rotating member in a first direction is transferred to said hub casing via said clutch, an if said rotating member is rotating at a velocity less that of said hub casing, said overrunning clutch disengages said hub casing from said rotating member.

40. A method of transmitting rotational energy from a drive member comprising the steps of: providing input power to an input portion of a first helical drive, said input power rotating an output portion of said first helical drive, said output portion of said first helical drive being coupled to a first input portion of a transmission system; transferring rotational energy from said first input portion of said transmission system to an output portion of said transmission system, said transmission system having a selectively variable transmission ratio to provide a variety of alternative transmission outputs for transferring rotational energy from said first input portion to said output portion of said transmission system; and coupling said output portion of said transmission system to said drive member so that an output force at output portion of said transmission system is transferred to said drive member.

41. A method of transmitting rotational energy according to claim 40, wherein said step of transferring rotational energy includes: transferring rotational energy at said output portion of said first helical drive to an input canier assembly operatively coupled to said output portion, wherein an axis of rotation of said input carrier assembly is substantially aligned with an axis of rotation of said output portion of said first helical drive; and selectively transfe╧Çing rotational energy at said input carrier assembly through a plurality of gears in said transmission system, which in an engaged position, transfers said rotational energy from said input carrier assembly to an output assembly, said plurality of gears being selectively engageable in various combinations to provide a variety of alternative transmission ratios for a transfer of rotational energy through said plurality of gears from said first input carrier assembly to said output assembly.

42. A method of transmitting rotational energy according to claim 41, said selectively transferring rotational energy at said input carrier assembly through a plurality of gears comprising the steps of: transferring rotational energy at a first transmission ratio by engaging said input carrier assembly to a ring gear carrier assembly, said ring gear carrier assembly being coaxially mounted inside of a ratchet shell cap, and engaging said ring gear carrier assembly to said ratchet shell cap, said ratchet shell cap being rotateably connected to said output assembly; transferring rotational energy at a second transmission ratio by engaging said input carrier assembly to said ring gear carrier assembly, engaging said ring gear carrier assembly to a planetary gear carrier assembly, said planetary gear carrier assembly being coaxially mounted inside of said ring gear assembly; transferring rotational energy at a third transmission ratio by engaging said input carrier assembly to said planetary gear carrier assembly, engaging said planetary gear carrier assembly to said ring gear carrier assembly, and engaging said ring gear carrier assembly to said ratchet shell cap; and selecting one of said first transmission ratio, said second transmission and said third transmission ratio.

43. A method of transmitting rotational energy according to claim 42, wherein: selectively engaging at least one of tapered splines on said input carrier assembly to at least one of cogs of said ring gear carrier assembly and carrier pins of said planetary gear carrier assembly; selectively engaging at least one of ratchet shell cap teeth to at least one of retractable pawls of said ring gear carrier assembly and pawls of planetary gear carrier assembly; and selectively engaging and disengaging gear or said ring gear assembly to at least one of pinion gears of said planetary gear carrier assembly.

44. A method of transmitting rotational energy according to claim 43, wherein said step of transferring rotational energy includes: transferring rotational energy at said output portion of said first helical drive to said first input portion of said transmission system through a non- zero angle, wherein an axis of rotation at said first input portion of said transmission system is at a first angle with respect to an axis of rotation of said output portion of said first helical drive, said first angle being greater than zero degrees; and selectively transferring rotational motion at said first input portion of said transmission system through a plurality of gears in said transmission system, which in an engaged position, transfer said rotational energy from first input portion of said transmission system to an output portion of said plurality of gears, said plurality of gears being selectively engageable in various combinations to provide a variety of alternative transmission ratios for a transfer of rotational energy through said plurality of gears from said first input portion of said transmission system to said output of said plurality of gears.

45. A method of transmitting rotational energy according to claim 40, wherein said step of transferring rotational energy includes: transferring rotational energy output by said first helical drive to an input carrier assembly operatively coupled to said output portion, wherein an axis of rotation of said input carrier assembly is substantially aligned with an axis of rotation of said output portion of said first helical drive; selectively transferring rotational energy at said input carrier assembly through a first plurality of gears in said transmission system, which in an engaged position, transfers said rotational energy from said input carrier assembly to an output assembly, said first plurality of gears being selectively engageable in various combinations to provide a variety of alternative transmission ratios for a transfer of rotational energy through said first plurality of gears from said input carrier assembly to said output assembly; transferring rotational energy at said output assembly to a first input gear through a non-zero angle, wherein an axis of rotation at said first input gear is at a first angle with respect to an axis of rotation of said output assembly of said first helical drive, said first angle being greater than zero degrees; and selectively transferring rotational motion at said first input gear through a second plurality of gears, which in an engaged position, transfer said rotational energy from first input gear to an output portion of said second plurality of gears, said second plurality of gears being selectively engageable in various combinations to provide a variety of alternative transmission ratios for a transfer of rotational energy through said second plurality of gears from said first input gear to said output portion of said plurality of gears.

46. A method of transmitting rotational energy according to claim 40, wherein said step of transferring rotational energy includes: transferring rotational energy output by said first helical drive to an input carrier assembly operatively coupled to said output portion, wherein an axis of rotation of said input carrier assembly is substantially aligned with an axis of rotation of said output portion of said first helical drive; selectively transferring rotational energy at said input carrier assembly through a first plurality of gears in said transmission system, which in an engaged position, transfers said rotational energy from said input carrier assembly to an output assembly, said first plurality of gears being selectively engageable in various combinations to provide a variety of alternative transmission ratios for a transfer of rotational energy through said first plurality of gears from said input carrier assembly to said output assembly; transferring an axis of rotation of rotational energy from said output assembly using a gear mechanism; transferring rotational energy at an output of said gear mechanism to a first input gear through a non-zero angle, wherein an axis of rotation at said first input gear is at a first angle with respect to an axis of rotation of said output of said gear mechanism, said first angle being greater than zero degrees; and selectively transferring rotational motion at said first input gear through a second plurality of gears, which in an engaged position, transfer said rotational energy from first input gear to an output portion of said second plurality of gears, said second plurality of gears being selectively engageable in various combinations to provide a variety of alternative transmission ratios for a transfer of rotational energy through said second plurality of gears from said first input gear to said output portion of said plurality of gears.

47. A method of transmitting rotational energy according to claim 40, further comprising the steps of: providing input power to an input portion of a second helical drive, said input power rotating an output portion of said second helical drive, said output portion of said second helical drive being operatively coupled to a second input portion of said transmission system through a non-zero angle, wherein an axis of rotation at said second input portion of said transmission system is at a second angle with respect to an axis of rotation of said output portion of said second helical drive, said second angle being greater than zero degrees; and selectively transferring rotational motion at said second input portion of said transmission system through said plurality of gears in said transmission system, which in an engaged position, transfers said rotational energy from at least one of said first and said second input portions of said transmission system to an output portion of said plurality of gears, which corresponds to an output portion of said transmission system, said plurality of gears being selectively engageable in various combinations to provide a variety of alternative transmission ratios for transferring rotational energy through said plurality of gears from at least one of said first and said second input portions of said transmission system to said output of said plurality of gears.

48. A method of transmitting rotational energy according to claim 40, wherein said step of transferring rotational energy includes: transferring rotational energy at said output portion of said first helical drive to a first input gear rotateably mounted on a first end portion of a main shaft, wherein an axis of rotation at said first input portion of said first input gear is at a first angle with respect to an axis of rotation of said output portion of said first helical drive, said first angle being greater than zero degrees, said main shaft also having an intermediate portion, wherein a first bushing is also rotateably mounted on said end portion of said main shaft and said first input gear is fixed to said first bushing such that rotation of said first input gear by said output portion of said first helical drive is transferred to said first bushing; transferring rotational energy from said first bushing to an orbital shaft having a first end operatively coupled to said first bushing such that rotation of said first bushing causes said orbital shaft to orbit said main shaft, said orbital shaft having an intermediate portion; selectively rotating a first ring gear as a result of the orbital movement of the orbital shaft about the main shaft, wherein rotational energy is transferred to said first ring gear is through a first planetary gear assembly that includes a first stationary gear mounted on said main shaft at said intermediate portion thereof, a first orbital gear rotateably mounted on said orbital shaft at said intermediate portion thereof, and said first ring gear mounted on a rotating member that rotates about said main shaft outside said an orbit of said orbital shaft; selectively rotating a second ring gear as a result of said orbital movement of said orbital shaft about said main shaft, wherein rotational energy is transferred to said second ring gear is through a second planetary gear assembly that includes a second stationary gear mounted on said main shaft at said intermediate portion thereof proximate to said first stationary gear, a second orbital gear rotateably mounted on said orbital shaft at said intermediate portion thereof proximate to said first orbital gear, and said second ring gear mounted on said rotating member; and selectively and alternatively actuating one of said first planetary gear assembly and said second planetary assembly by selectively positioning said first orbital gear in an engaged relationship with said first stationary gear and said first ring gear while said second orbital gear is disengaged and by positioning said second orbital gear in an engaged relationship with said second stationary gear and said second ring gear while said first orbital gear is disengaged; wherein if said first orbital gear is in said engaged relationship with said first stationary gear and said first ring gear, orbital rotation of said orbital shaft about said main shaft induces a rotation in said first orbital gear that is transferred to said first ring gear, thereby rotating said rotating member at a first transmission ratio, wherein, if said second orbital gear is in said engaged relationship with said second stationary gear and second first ring gear, orbital rotation of said orbital shaft about said main shaft induces a rotation in said second orbital gear that is transferred to said second ring gear, thereby rotating said rotating member at a second transmission ratio, and wherein diameters of said first stationary gear, said first orbital gear, and said first ring gear are different from diameters of said respective second stationary gear, said second orbital gear, and said second ring gear so that said first transmission ratio is different from said second transmission ratio.

49. A method of transmitting rotational energy according to claim 48, further comprising the step of engaging said orbital shaft to said first bushing through an overrunning clutch.

50. A method of transmitting rotational energy according to claim 48, wherein said step of selectively and alternatively actuating one of said first planetary gear assembly and said second planetary assembly includes moving a bolt slidable disposed in a hollow center of said intermediate portion of said main shaft along a lengthwise direction of said main shaft between a first position and a second position, said bolt having an arm that extends from said main shaft through a slot defined along a lengthwise direction of said main shaft, said first and said second orbital gears being operatively coupled to said arm such that if said bolt is in said first position, said first orbital gear is in said engaged relationship with said first stationary gear and said first ring gear and said second orbital gear is disengaged, and if said bolt is in said second position, said second orbital gear is in said engaged relationship with said second stationary gear and said second ring gear and said first orbital gear is disengaged.

51. A method of transmitting rotational energy according to claim 48, wherein said drive member is a hub casing adapted to rotate about said main shaft outside said rotating member, said step of transferring rotational energy comprises the step of: transferring rotational energy from said rotating member to said hub casing through an overrunning clutch coupling said hub casing to said rotating member such that rotation of said rotating member in a first direction is transferred to said hub casing via said clutch, an if said rotating member is rotating at a velocity less that of said hub casing, said overrunning clutch disengages said hub casing from said rotating member.

52. A method of transmitting rotational energy according to claim 48, further comprising: providing input power to an input portion of a second helical drive, said input power rotating an output portion of said second helical drive, said output portion of said second helical drive being operatively coupled to a second input portion of said transmission system; transferring rotational energy at said output portion of said second helical drive to a second input gear rotateably mounted on a second end of said main shaft, wherein an axis of rotation of said second input gear is at a first angle with respect to an axis of rotation of said output portion of said second helical drive, said second angle being greater than zero degrees, wherein said second input gear is fixed to a second bushing, which is also rotateably mounted on said second end of said main shaft, such that rotation of said second input gear by said output portion of said second helical drive is transferred to said second bushing; transferring rotational energy from said second bushing to said orbital shaft, said orbital shaft having a second end operatively coupled to said second bushing such that rotation of said second bushing causes said orbital shaft to orbit said main shaft; selectively coupling said first bushing to said first end of said orbital shaft through a first overrunning clutch and selectively coupling said second bushing to said second end of said orbital shaft through a second overrunning clutch so that rotational motion is provided to said orbital shaft via at least one of said first and said second bushings through at least one of said first and said second overrunning clutches enabling said first and said second input gears to be actuated independently of one another by said respective first and second helical drives.

53. A method of transmitting rotational energy according to claim 52, wherein said step of selectively and alternatively actuating one of said first planetary gear assembly and said second planetary assembly includes the step of moving a bolt slidable disposed in a hollow center of said intermediate portion of said main shaft along a lengthwise direction of said main shaft between a first position and a second position, said bolt having an arm that extends from said main shaft through a slot defined along a lengthwise direction of said main shaft, said first and said second orbital gears being operatively coupled to said arm such that if said bolt is in said first position, said first orbital gear is in said engaged relationship with said first stationary gear and said first ring gear and said second orbital gear is disengaged, and if said bolt is in said second position, said second orbital gear is in said engaged relationship with said second stationary gear and said second ring gear and said first orbital gear is disengaged.

54. A method of transmitting rotational energy according to claim 53, wherein said drive member is a hub casing adapted to rotate about said main shaft outside said rotating member, said step of transferring rotational energy comprises the step of: transferring rotational energy from said rotating member to said hub casing through a third overrunning clutch coupling said hub casing to said rotating member such that rotation of said rotating member in a first direction is transferred to said hub casing via said third overrunning clutch, an if said rotating member is rotating at a velocity less that of said hub casing, said third overrunning clutch disengages said hub casing from said rotating member.

55. A bicycle comprising: a frame; a rear wheel having a hub mounted to a first portion of said frame; a front wheel mounted to a second portion of said frame; and a helical drive system comprising: a first helical drive mounted on said frame and having an input portion and an output portion; a first input device operatively coupled to said input portion of said first helical drive such that actuation of said first input device rotates said output portion of said first helical drive; and a transmission system having an input portion and an output portion, said input portion of said transmission system being operatively coupled to said output portion of said first helical drive, said transmission system having a selectively variable transmission ratio to provide a range of alternative transmission ratios for transferring rotational motion between said input portion and said output portion of said of said transmission system.

56. A bicycle according to claim 55, wherein said transmission system comprises a first in-line multi-gear assembly comprising: an input carrier assembly operatively coupled to said output portion of said first helical drive such that an axis of rotation of said input carrier assembly is substantially aligned with an axis of rotation of said output portion of said first helical drive; a gear assembly coupled to said input carrier assembly, said gear assembly having a plurality of gears selectively engageable in various combinations to provide said selectively variable transmission ratio; and an output assembly coupled to said gear assembly.

57. A bicycle drive system according to claim 56, wherein said plurality of gears include: a ratchet shell cap having a cylindrical shape with a hollow center defined therein, said ratchet shell cap being rotateably connected to said output assembly; a ring gear carrier assembly having a cylindrical shape with a hollow portion defined therein, said ring gear carrier being concentrically located inside said ratchet shell cap; and a planetary gear carrier assembly having a cylindrical shape with a hollow center portion defined therein, said planetary gear carrier being concentrically located inside said ring gear carrier; wherein said input carrier assembly, said ring gear carrier assembly and said ratchet shell cap are adapted to be rotateably engaged such that a rotation of said input carrier assembly induces a rotation of said output assembly at a first transmission ratio; wherein said input carrier assembly, said ring gear carrier assembly, said planetary gear carrier assembly and output assembly are adapted to be rotateably engaged such that a rotation of said input carrier assembly induces said rotation of said output assembly at a second transmission ratio; and wherein said input carrier assembly, said planetary gear carrier assembly, said ring gear carrier assembly and said ratchet shell cap are adapted to be rotateably engaged such that said rotation of said input carrier assembly induces a rotation of said output assembly at a third transmission ratio.

58. A bicycle according to claim 57, further comprising: a second helical drive mounted to said frame having an input portion and an output portion; and a second input device operatively coupled to said input portion of said second helical drive such that actuation of said second input device rotates said output portion of said second helical drive; and wherein said transmission system further comprises a second in-line multi- gear assembly comprising: an input carrier assembly operatively coupled to said output portion of said second helical drive such that an axis of rotation of said input carrier assembly is substantially aligned with an axis of rotation of said output portion of said second helical drive; and a gear assembly coupled to said input carrier assembly, said gear assembly having a plurality of gears selectively engageable in various combinations to provide said selectively variable transmission ratio; an output assembly coupled to said gear assembly.

59. A bicycle according to claim 55, wherein said transmission system comprises a multi-gear hub assembly comprising: a first input gear operatively coupled to said output portion of said first helical drive such that an axis of rotation of said first input gear is at a first angle relative to an axis of rotation of said output portion of said first helical drive, said first angle being greater than zero degrees; and a gear assembly having a first input portion, which is operatively coupled to said first input gear, an output portion, and a plurality of gears which, in an engaged position, transfer rotational energy from said first input portion to said output portion of said gear assembly, said plurality of gears being selectively engageable in various combinations so as to provide said range of alternative transmission ratios between said first input portion and said output portion of said gear assembly.

60. A helical drive system according to claim 59, wherein said gear assembly comprises: a main shaft having end portions and an intermediate portion; a first bushing rotateably mounted on said end portion of said main shaft, said first input gear being fixed to said first bushing, wherein rotation of said first input gear by said output portion of said first helical drive is transferred to said first bushing; an orbital shaft having a first end operatively coupled to said first bushing such that rotation of said first bushing causes said orbital shaft to orbit said main shaft, said orbital shaft having an end portion coupled to said bushing and an intermediate portion; a rotating member adapted to rotate about said main shaft outside an orbit of said orbital shaft; a first stationary gear mounted on said main shaft at said intermediate portion thereof; a first orbital gear rotateably mounted on said orbital shaft at said intermediate portion thereof; a first ring gear mounted on said rotating member; a second stationary gear mounted on said main shaft also at said intermediate portion thereof proximate to said first stationary gear; a second orbital gear mounted on said orbital shaft at said intermediate portion thereof proximate to said first orbital gear; a second ring gear mounted on said rotating member; and a shifting mechanism that selectively and alternatively positions said first orbital gear in an engaged relationship with said first stationary gear and said first ring gear and said second orbital gear in an engaged relationship with said second stationary gear and said second ring gear, wherein, if said first orbital gear is in said engaged relationship with said first stationary gear and said first ring gear, orbital rotation of said orbital shaft about said main shaft induces a rotation in said first orbital gear that is transferred to said first ring gear, thereby rotating said rotating member at a first transmission ratio, wherein, if said second orbital gear is in said engaged relationship with said second stationary gear and second first ring gear, orbital rotation of said orbital shaft about said main shaft induces a rotation in said second orbital gear that is transferred to said second ring gear, thereby rotating said rotating member at a second transmission ratio, and wherein diameters of said first stationary gear, said first orbital gear, and said first ring gear are different from diameters of said second stationary gear, said second orbital gear, and said second ring gear so that said first transmission ratio is different from said second transmission ratio.