GB2277065A

GB2277065A - A variable ratio transmission for a cycle

Info

Publication number: GB2277065A
Application number: GB9307880A
Authority: GB
Inventors: Dragan Martalog Bukatarevic
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-04-16
Filing date: 1993-04-16
Publication date: 1994-10-19
Also published as: GB9307880D0

Abstract

The transmission is provided between the pedals and the propelled axle. The crankwheel 1 drives a gear 3, which drives gear 4, which is eccentrically mounted with respect to chainwheel 7. Links 5 and 6, pivoted on gearwheels 1, 3 and 4 centre axes, ensure that the gears remain in mesh. Due to the eccentric mounting of gear 4, the transmission ratio between the pedals 2 and the output chain 8 varies cyclically with rotation of gear 4. The variation is preferably sinusoidal and is arranged to have a maximum ratio when the pedal cranks are horizontal. Two gear trains may be provided (Figs 11 - 14) to enable each pedal drive ratio to vary independently. <IMAGE>

Description

A PHASE CONTROL SYSTEM FOR A PEDAL PROPELLED VEHICLE This invention relates to a phase control system of a kind which, in accordance with changes in the angular phase of the propelling axle, in relation to the angular phase of the propelled axle, namely; a non-linear transition of the periphertal velocity through a phase controlled mechanism, situated between the propelling and the propelled axle, and by means of changes in the angular phase resembling or being equivalent to a sine or inverse sine function, transforms a semi-periodical moment of the propelling axle, as for instance the action of the pedals of a bicycle, into a form of angularly spread moment, with defined small angular gap of zero-to average moment between the adjacent periods; or into a form of a smooth and uninterrupted moment, with a defined small variation; being close to the average value of a semi-periodical moment of the propelling axle, and in that form delivered to the propelled axle, as for instance the propelling wheel of a bicycle.

This invention, by delivering an evenly-spread or continuous moment, aims to provide a more comfortable ride of the bicycle on an uphill gradient; with a greater fluidity of movement, at the minimum speed, without a prominent jerking effect. By reducing the time-period of a non-yielding action of forces applied to the pedals at and near their extreme vertical positions, it thus decreases the fatigue factor and minimizes the depletion of the rider's energy.

This invention will now be described in more details with reference to the accompanying drawings, in which: Figure 1 shows an embodiment of the phase control system; Figure 2 shows a change of phase of the pedals' axle (p) in relation to the phase of the sprocket wheel axle (w) during one revolution, relating to the system shown in Figure 1; Figure 3 shows a change of the moment (M) during one revolution of the sprocket wheel axle (W), without (p) and with the phase control system (w), shown in Figure 1; Figure 4 shows a variation of the phase control system; Figure 5 shows a change of phase of the pedals' axle (p) in relation to the phase of of the sprocket wheel axle (w) during one revolution, relating to the system shown in Figure 4; Figure 6 shows the four different positions of the pedals in relation to the four angular positions (900,1800,270" and 3600) of the sprocket wheel axle (W), relating to the system shown in Figure 4; Figure 7 shows a change of moment during one revolution of the sprocket wheel axle (W), without (p) and with the phase control system (w) and change of the pedals' velocity (v), relating to the system shown in Figure 4; Figure 8 shows a detail from the system shown in Figures 1 and 4; Figure 9 shows a phase control system incorporated into the sprocket wheel; Figure 10 shows a cross-section of the system shown in Figure 9; Figure 11 shows a cross-section of a phase control system consisting of the two counterphasical mechanisms propelled separately by each of the pedals; Figure 12 shows a change of phase of both pedals' (2',2") in relation to the position of the sprocket wheel during one revolution, relating to the system shown in Figure 11; Figure 13 shows a change of the moment during one revolution of the sprocket wheel (W), without (pl,p2) and with (w) the phase control system, shown in Figure 11; Figure 14 shows the three positions of both pedals (pl,p2) during a half revolution of the sprocket wheel, relating to the system shown in Figure 11; Figure 15 shows a variation of the phase control system; Figure 16 shows a phase deviation (P-W) of both pedals in relation to the sprocket wheel (W), relating to the system shown in Figure 15; Figure 17 shows a side-view of the system shown in Figure 15; Figure 18 shows a front-view position of the pedal and fitting within a frame-work of a bicycle, relating to the system shown in Figure 15; Figure 19 shows a variation of a phase control system; Figure 20 shows a cross-section of the system shown in Figure 19.

The individual parts in Figures 1-20 of the same shape and function are indicated with the same reference number.

A phase control system shown in Figure 1 consist of: a gear. 1 mounted on the axle (P), which is propelled by the pedals 2; a gear 4 is eccentrically mounted on the cranked portion (E) of the axle (W) and propels the sprocket wheel 7; an intermediate gear 3 which is mounted on the intermediate axle (I) and meshing with gears 1 and 4; the gears are maintained at constant centres by sets of connecting links 5 and 6, or by connecting links 6 and the grooves 14, which guide the intermediate axle (I); the chain 8 carries the moment from sprocket wheel towards a propelling wheel. The eccentricity of gear 4 is positioned in the way as shown in Figure 1, delivering a maximum leading phase (a) at the anti-clockwise turn of 900 and a maximum lagging phase at the turn of 2700; as shown in Figure 2. A change of phase between the axles (P,W) resembles a sine function.

A phase control system shown in Figure 4 consists of: A sprocket wheel 11, which is mounted on axle (P) and propelled by the pedals 2, propels a twice smaller sprocket wheel 7 by the chain 12; a gear 4 is eccentrically mounted on the cranked portion (E) of the axle (PO) and propelled by the sprocket wheel 7; a gear 9 and a sprocket wheel 7 are mounted on the axle (W). The rest of the parts, including the groove 14a are used and function in the same way as in the system described previously. A change of phase between the axles (P,W), which resemble an inverse sine function, transforms the moment into more evenly spread moment, comparing to the spread of moment in the preceding system. By turning the propelling wheel of a bicycle, which represents a linear co-ordinate, so that the axle (W) turns to 900, the movement of pedals is determined by the portion A, as shown in Figures 5 and 6; by further turning from 900 to 1800 and to 2700, the movement of pedals is determined by portions B, which are a few times smaller then the portions A. Consequently, the propelling force has a greater virtual distance from the centre of rotation during the portions A; thus causing a greater moment in relation to the moment during the portions B. The velocity of pedals (v) which is proportional to a virtual distance, reaches its maximum at the extreme vertical positions (00,1800) and its minimum at the inter-mediate positions (900,2700) of the pedals. A transformed moment (w) reaches the average value rapidly, leaving a small angular gap of zero-to average in the propelling wheel axle of a bicycle. Theoretically, the gap becomes zero for the amplitude of phase fluctuation of 1 radian.

For the amplitude of 0.7 radians the gap is 150, or less than one fifth of its normal value without a phase control system. If a rider is seated, then the pressure on the pedals comes instantly from the muscles of the rider, in which case, by reducing the lasting time of zero-to average moment within one cycle, (the time of higher resistance), the production of heat from the rider's body recedes; thus reducing the fatigue factor.

The system shown in Figure 9 is incorporated into a hollow cylinder 17, which has the gear teeth on the inner side and meshes with gear 1.

A sprocket wheel lla is a part of the cylinder and can rotate on axle (P).

The two round plates, 15 and 16, are attached to the frame of a bicycle 18, and kept together by links 13. This system operates in the same way as the system shown in Figure 1.

The system shown in Figure 11 consists of: The two counter-phasic systems in which cranked axles (P',P") are connected to the pedals (2',2") separately, and meshing with the two sets of gear teeth on the inner side of the cylinder 17. The round plate 19 separates the two systems. The three gears 3,4 and 9 have the same diameter. The phase fluctuations, for both pedals (pl,p2), and their positions in relation to the rotation of axle (W). are shown in Figures 12 and 14. In the initial stage (W=0), the pedal (pl) has a leading phase (+b), and the pedal (p2) has a lagging phase (-b). By turning the axle (W) to 90d, both pedals are in phase with the axle , given that the phase of pedal (p2) has a delay of 1800. By further turning to 1800 the pedal (pl) has a lagging phase (-b) and the pedal (p2) leading phase (+b). The pressure on pedals is applied between the two positions +b,-b alternatively; thus delivering a continuous moment at the axle (W); gear 9 shown in Figure 13, which further propels the cylinder 17, the sprocket wheel lla, and the propeling wheel of a bicycle.

The system shown in Figures 15,16 and 18 is a system which delivers continuous moment to the propelling wheel of a bicycle. A stationary cylinder 20, which is incorporated into a frame of a bicycle 27,28, has on both sides identical grooves 21 in the shape of asymmetric and eccentric ellipse, with reference to the centre of the cylinder. The sprocket wheel 24 and the round plate 25 have identical slots 23. The slot on the plate 25 is turned 1800. The axle 26, which freely rotates in the centre of the cylinder 20, connects the plate 25 and the sprocket wheel 24. The steel balls 22 are occupying the space which is common to the grooves 21, the slots 23 and the grooves 35, on the pedals levers; which could turn freely on axle 26. The groove 21 is shaped in a way that produces the sinusoidal phase fluctuations between the sprocket wheel 24 and the pedals (2',2"), shown in Figure 16 (pl,p2). The performance of this system is analogous to the preceding system.

The system shown in Figures 19 and 20 consists of: The two identical counter-phasically fitted systems; one for each pedal. The two gears 29, are stationary and connected, one on each side, to the frame of a bicycle (27,28). A planetary gear 30, having the same diameter as gear 29, freely rotates on the axle 33 and is meshed with gear 29. The axle 33 is fixed to the pedal lever 2; pivot 34, which is eccentrically fixed to gear 30, is inserted into groove 32 on the sprocket wheel 35, (without the sprocket on the other side). The sprocket wheel 35 and corresponding round plate on the other side are connected to the round plates 36, which are fixed to the axle 37. A curved slot 31 allows a free movement of the axle 33.

The four positions of the pedal (2') in relation to the sprocket wheel 35,(00,900,1800,2700), are shown in Figure 19. The position of pedal (2') at 1800 corresponds to the initial position (00) of the pedal (2"). The performance of this system is analogous to the preceding system and to the system shown in Figure 11.

Claims

1. A phase control system for a pedal propelled vehicle, and the method of a kind which, in accordance with periodic changes in the angular phase of a propelling axle, in relation to the angular phase of a propelled axle, namely, a non-linear transition of the peripherial velocity through a phase control mechanism, situated between the propelling and the propelled axles, which by means of changes in the angular phase resembling or being equivalent to the two full periods of a sine or inverse sine function, transforms a semi-periodiodic moment of the propelling axle, as for instance a moment occuring at the pedals of a bicycle, into a form of an angularly spread moment, with defined variations being close to the average value of a semiperiodic moment, and with defined small gaps of zero-to average moment, between the adjacent periods, and in that form delivered to the propelled axle, as for instance the propelling wheel of a bicycle.

2. A phase control system as claimed in claim 1, which consists of two counterphasical systems, with common or synchronous axles, which by means of changes in the angular phase resembling or being equivalent to the one full period of a cosine or inverse cosine function, and which are propelled separately by the two independent pedals, each having the leading and the lagging phase in relation to the propelled axle, and being counterphasical to each other; thus the actions on the pedals could overlap each other, delivering a smooth and uninterrupted moment at the propelled axle, as for instance the propelling wheel of a bicycle.

3. A phase control system as claimed in claim 1, and wherein a phase control mechanism consists of a gear which is mounted on the pedals axle and meshes with the twice smaller intermediate gear, which further meshes with a gear of the same size as the intermediate gear, and is mounted on the cranked portion of the separate axle fitted with the sprocket wheel, and the three meshing gears are maintained at constant centres by sets of links, between the pedals axle and the intermediate gear axle, and between the intermediate gear axle and the sprocket wheel axle.

4. A phase control mechanism as claimed in claims 1 and 3, wherein the three meshing gears are of the same size, and the axle of the gear which is mounted on the cranked portion is fitted with a sprocket wheel, which is, by means of a chain, propelled by a twice as large sprocket wheel mounted on the pedals axle, and the other side gear axle is fitted with a sprocket wheel, which, by means of a chain, propels a propelling wheel of a bicycle, or vice versa.

5. A phase control mechanism as claimed in claims 1 and 3, wherein the mechanism is incorporated within a sprocket wheel, mounted on the pedals axle, on which it can rotate freely, and in a shape of hollow cylinder with attached sprocket wheel, and has the gear teeth on the inner side, which meshes with the three meshing gears, and the axle of the eccentric gear is propelled by the pedals.

6. A phase control system as claimed in claim 2 and 5, wherein the system consists of the two counterphasical mechanisms, with the meshing gears of the same size, and which are fitted on the same side; or one on each side of the frame of a bicycle, in the centre of the pedals axle, and in the shape of one or two interconnected hollow cylinders, one of which has a fitted sprocket wheel; and the mechanisms are propelled by each pedal, independently, with the leading and lagging phases of the pedals being counterphasical to each other.

7. A phase control mechanism as claimed in claim 2, wherein the mechanism consists of: two inner plates, fitted separately, or adjacent to each other, preferably in the shape of a solid, or hollow, cylinder, added to, or being incorporated into a frame-work of a bicycle, with its centre corresponding to the pedals axle, and which, on both plain sides, has the grooves in shape which resemble an eccentric and asymmetric ellipse, in relation to the centre, and has an inclination in relation to the vertical axis; then the outer round plate interconnected through the centre with the sprocket wheel, adjacent to the cylinder and can freely rotate, and having the two slots, which are identical but 1800 turned in relation to each other, and with the inclination in relation to the radius; then the grooves on the pedals levers, and the two steel balls which occupy a space which is common to the slots, the pedals grooves, and the elliptical grooves; the relation between the grooves and the slots being such, that one full rotation of the sprocket wheel corresponds to the phase fluctuations of pedals resembling cosine or inverse cosine function.

8. A phase control mechanism as claimed in claims 2 and 7, wherein the mechanism consists of: two stationary gears connected on both sides to the frame-work of a bicycle, the planetary gears, which freely rotate on axles connected to the pedals, and with eccentrically fixed pivots, which are inserted into the radial grooves, or slots, on the sprocket wheel and the interconnected round plate, or the planetary gears are fixed to the sprocket wheel and the round plate, and having the grooves on the pedals levers.

9. A phase control system as claimed in claim 1, wherein the system consists of a phase- control mechanism of the kind which intercepts the transfer of the moment between the pedals and the propelling wheel of a bicycle, at any location, including the locations at pedals and the propelling wheel axles, and acts in the way which, at the constant peripheral velocity of a propelling wheel of a bicycle, causes a periodic fluctuations of the peripheral velocity of pedals, and having their maximum velocity at, or near, the extreme vertical positions of the pedals, and their minimum velocity at, or near, the intermediate positions of the pedals.

10. A phase control system as claimed in claims 2 and 9, wherein the peripheral velocity for each of the pedals, separately, have the maximum at, or near, the extreme back and the minimum at, or near, the extreme front horizontal positions of the pedals, given that the front is determined by the active path of the cycle.