CN116745230A

CN116745230A - Self-rolling strip driving mechanism

Info

Publication number: CN116745230A
Application number: CN202180086960.2A
Authority: CN
Inventors: B·赛伸斯; T·塞普
Original assignee: Riverview Inc Operates In Name Of Les Robotics
Current assignee: Riverview Inc Operates In Name Of Les Robotics
Priority date: 2020-12-23
Filing date: 2021-12-21
Publication date: 2023-09-12

Abstract

The present disclosure relates to a tape drive mechanism that may be used to pay out tape to or withdraw tape from a tape actuation system (or tape driven system). The mechanism features a self-winding spool that automatically winds and unwinds portions of the tape as the tape is withdrawn from or fed to the tape actuation system. A second rotational shaft (idler shaft) with one or more pulleys (e.g., pulleys of a pulley, or rollers) may be rotatably coupled to the capstan via the tape and may be used to drive additional mechanisms in the tape drive mechanism, such as a winding mechanism.

Description

Self-rolling strip driving mechanism

Cross Reference to Related Applications

The present application claims priority from U.S. provisional patent application Ser. No. 63/129,695, filed on 12/23/2020, and U.S. patent application Ser. No. 17/335,269, filed on 6/2021, which are incorporated herein in their entireties for all purposes.

Technical Field

The present disclosure relates generally to a self-winding tape drive.

Background

The new strip has many desirable characteristics. They can be lightweight, low maintenance, and have high strength under tension. Many new and old applications of new straps are currently being adapted.

Disclosure of Invention

In general, the present disclosure relates to a self-winding strap drive mechanism including a winch configured to withdraw or pay out strap from or to a strap actuation system and an idler shaft coupled to the winch via the strap. The idle shaft is configured to rotate in the extraction direction when the capstan rotates in the extraction direction, and to rotate in the payout direction when the capstan rotates in the payout direction. The idler shaft includes a first end configured to receive one or more turns of the strap, a second end coupled to the first one-way lock bearing, and a first gear coupled to the first one-way lock bearing. The first one-way locking bearing engages when the idler shaft rotates in the extraction direction, causing the first gear to rotate with the rotating idler shaft. The first one-way lock bearing is disengaged when the idler shaft rotates in the payout direction, allowing relative movement between the first gear and the idler shaft. The tape drive mechanism further includes a tape shaft that receives or pays out a portion of the tape, the tape shaft including an outer hub configured to rotate about an outer circumference of the outer hub and wind or unwind a portion of the tape, and a second gear in frictional engagement with the outer hub. The second gear is configured to be driven by the first gear such that the first gear drives the second gear, resulting in rotating the outer hub in a direction of the portion of the wound strip when the idler shaft is rotated in the extraction direction.

Implementations may optionally include one or more of the following features.

In some embodiments, the belt shaft includes an inner hub connected to the central shaft via a second one-way locking bearing. The second one-way locking bearing allows the inner hub to rotate relative to the central shaft when the outer hub rotates in the direction of the portion of the wound strip. The second one-way locking bearing prevents rotation between the inner hub and the central shaft when the outer hub is in the direction of the portion of the unwind strip. The inner hub may be frictionally engaged with the outer hub such that the outer hub overcomes the frictional force between the inner and outer hubs to rotate relative to the inner hub when rotated in the direction of the portion of the unwind strip.

In some embodiments, the first gear of the strap drive mechanism is a bevel gear and the second gear is a ring gear.

In some embodiments, the second gear is configured to overspeed the outer hub at least 1.5% faster than the outer hub.

In some embodiments, the strap passes through the strap actuation system and returns to the strap drive mechanism such that both the first and second ends of the strap are within the strap drive mechanism, and the extraction and payout of the strap actuate the strap actuation system. In some embodiments, the strap actuation system includes a trolley that expands or contracts as the strap is extracted from or paid out to the strap actuation system.

In some embodiments, at least one end of the strap is electrically connected to circuitry in the strap drive mechanism. The circuit may measure at least one electrical parameter associated with the strip.

In some embodiments, the strap drive mechanism includes an encoder wheel including an outer surface having ribs that engage grooves in the strap. The shaft of the encoder wheel may be connected to the encoder.

The present disclosure describes a tape drive mechanism that may be used to pay out tape to or withdraw tape from a tape actuation system (or tape driven system). The mechanism features an automatic winding spool that can be used to automatically wind or unwind portions of the tape as the tape is drawn from or fed to the tape actuation system. The tape driven system may have many advantages over other similar systems. For example, a ribbon driven linear actuator may require less maintenance, be lighter weight, and be capable of more cycles than a similar hydraulic linear actuator. Many strap drive mechanisms include a capstan that can receive one or more turns or portions of the strap and provide rotational force to draw/in or pay out the strap. The winch may be powered by, for example, an electric motor, via a set of reduction gears, or a hydraulic motor. In some embodiments, a second rotational shaft (e.g., an idler shaft) with one or more pulleys (e.g., pulleys (rollers)) may be rotationally coupled to the winch via the strap and may be used to drive additional mechanisms in the strap drive mechanism, such as a winding mechanism described below.

Implementations may include one or more of the following advantages. In some embodiments, the strap drive mechanism includes a friction driven strap shaft that allows the rotational speed of the strap shaft to be varied independently of the strap drive capstan and the idler shaft. This ensures that tension is maintained throughout the operation of the tape drive mechanism without the need for variable gearing or other complex systems to manage the rotational speed of the various components. The system of unidirectional locking bearings and friction surfaces makes the self-winding mechanism mechanically simple, compact, and robust over the entire range of operation of the tape drive mechanism.

During constant rate winding, the effective diameter of the tape shaft will increase as the tape is wound around the tape shaft. Similarly, the effective diameter of the tape spool will decrease during unreeling. Since the diameter is not constant, the rotational speed of the tape shaft may be varied to continue to draw (or pay out) the tape at a constant rate. As described in more detail below, the belt shaft may be driven through the idler shaft via friction, allowing for a difference in rotational speed between the belt shaft and the idler shaft. For example, the idler shaft may have a bevel or milling cutter gear affixed to one end that engages a ring gear that frictionally engages the side of the belt shaft. The gearing between the bevel gear and the ring gear may be such that the ring gear will rotate faster than necessary for the belt shaft to roll in the belt. The ring gear may press against the sides of the belt shaft (e.g., via springs), and the revolving ring gear may frictionally drive the belt shaft at a slower rate. The slower rate may be limited by the tension in the strap. As the belt shaft fills with the belt and its effective diameter increases, it can slow down while still being frictionally driven by the rotating ring gear.

During unreeling, the tension provided by the strip may provide a moving force to unreel the tape spool. However, additional problems can occur if the tape spool is free to rotate in the unwinding direction. For example, as the spool gains angular momentum, it tends to continue to rotate after the winch stops, potentially introducing slack into the system and causing the winch to lose traction of the strap. A second mechanism may be provided which imparts a rotational friction to the spool that is applied only when the spool is unreeled, thus preventing the introduction of slack from the freely rotating spool. In one embodiment, the belt shaft may include an outer hub around which the belt is wound and an inner hub frictionally engaged with the outer hub such that the outer hub must overcome a predetermined amount of friction to rotate relative to the inner hub. In this embodiment, the inner hub may be mounted to a shaft via a one-way locking bearing that allows the inner hub to rotate about the shaft in one direction (e.g., when the tape shaft is wound in a ribbon) and prevents the inner hub from moving relative to the shaft in a second direction (e.g., when the tape shaft is unwound). In this way, during unreeling, the inner hub remains stationary while the outer hub rotates around the inner hub via the straps, overcoming the friction between the inner and outer hubs.

The details of one or more implementations of the subject matter of the specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

Drawings

In order to more clearly describe embodiments of the present specification or technical solutions in the prior art, the drawings required for describing the embodiments or the prior art are briefly introduced below. It is evident that the figures in the following description show only some embodiments of the present description, and that other figures can still be derived from these figures by a person skilled in the art without inventive effort.

Fig. 1A depicts a side view of a linear actuator that includes a strap drive mechanism and a strap actuation mechanism.

Fig. 1B depicts a perspective view of the linear actuator of fig. 1A.

Fig. 2 depicts a right side view of the tape drive mechanism of the linear actuator of fig. 1A and 1B.

Fig. 3 depicts a left side view of the tape drive mechanism of the linear actuator of fig. 1A and 1B.

Fig. 4 depicts a strip of the strip drive mechanism of the linear actuator of fig. 1A and 1B.

Fig. 5 depicts a cross-sectional view of a retaining strap and a tensioning roller of the strap drive mechanism of the linear actuator of fig. 1A and 1B.

Fig. 6 depicts a cross-sectional view of a self-winding mechanism of the ribbon drive mechanism of the linear actuator of fig. 1A and 1B.

Fig. 7A and 7B depict a manually operated crane of another embodiment of a strap drive mechanism.

Like reference numbers and designations in the various drawings indicate like elements.

Detailed Description

The present disclosure describes a tape drive mechanism that may be used to pay out tape to or withdraw tape from a tape actuation system (or tape driven system). The mechanism features a self-winding spool that automatically winds and unwinds portions of the tape as the tape is withdrawn from or fed to the tape actuation system. The tape driven system may have many advantages over other similar systems. For example, a ribbon driven linear actuator may require less maintenance, be lighter weight, and be capable of more cycles than a similar hydraulic linear actuator. Many strap drive mechanisms include a capstan that can receive one or more or partial turns of the strap and provide rotational force to draw/in or pay out the strap. The winch may be powered by, for example, an electric motor, via a set of reduction gears, or a hydraulic motor. In some embodiments, a second rotational shaft (e.g., an idler shaft) with one or more pulleys (e.g., pulleys of a pulley, or rollers) may be rotatably coupled to the winch via the strap and may be used to drive additional mechanisms in the strap drive mechanism, such as a winding mechanism described below.

In order to help those skilled in the art to better understand the technical solutions in the present specification, the technical solutions in the embodiments of the present specification are clearly and fully described below with reference to the drawings in the embodiments of the present specification. It will be apparent that the described embodiments are only some, but not all, of the embodiments of the present specification. All other embodiments that come within the scope of embodiments of the present description, based on one or more embodiments of the present description, without inventive effort, should be made by one of ordinary skill in the art.

Fig. 1A and 1B depict an example linear actuator 100 that includes a tape drive system 101 coupled with a tape actuation mechanism 102. As shown, the linear actuator with the strap drive mechanism 101 may take a similar size profile as a standard hydraulic cylinder. In this example, the strap actuation mechanism 102 may include one or more trolley groups (sliders and cords) with multiple strap free spans therein. Extraction of the strap from the strap actuation mechanism 102 causes it to retract. Similarly, paying out the strap to the strap actuation mechanism 102 may allow it to expand. As shown and for simplicity, a single strap drive mechanism 101 is applied and a moving force is applied in only one direction (e.g., the contracting direction) and the strap actuation mechanism 102 is expanded depending on gravity or other forces. In some embodiments, multiple strap drive mechanisms 101, or different configurations of strap actuation mechanisms 102, may be provided to accommodate bi-directional application of motive force (e.g., powered expansion and contraction). Further, although shown as a linear actuator, the strap actuation mechanism 102 may be any system configured to operate using a strap. The present disclosure contemplates a number of strap actuation mechanisms, such as linear actuators, rotary actuators, cranes, pumps, conveyors, and other strap actuation systems.

Fig. 2 depicts a right side view of the tape drive mechanism 101. For clarity, some of the structure and housing components are not shown in fig. 2. A motor and gearbox (e.g., an electric motor) or other device may rotate the driven shaft 202, which provides a motive force for the operation of the tape drive mechanism 200. Winch 204 may be configured to accept multiple turns of strap 218, each turn providing more friction and increasing the amount of tension winch 204 may apply to strap 218. As shown in fig. 2, strap 218 completes three half turns around capstan 204, and the remaining three half turns pass through to rotate around idler shaft (idler shaft) 206. The space between the idler shaft 206 and the capstan 204 creates multiple free spans of strap that minimize the torsion and rotation angle of the strap 218 to reduce wear. The idler shaft 206, which may share these bands with the winch 204, may be supported by one or more bearings, allowing the idler shaft 206 to rotate as the strap 218 passes thereabout. In this way, the idler shaft 206 and the driven shaft 202 rotate in generally the same direction, although their axes may not coincide. A bevel gear 208 may be attached to one end of the idler shaft. Although shown as bevel gears, any suitable gears (e.g., spur gears, helical gears, worm gears, milling gears, etc.) may be used.

Bevel gear 208 is engaged with a ring gear 210 that is in frictional engagement with a belt shaft (about a belt frame) 212 such that rotation of bevel gear 208 causes rotation of ring gear 210, which transmits frictional forces to rotate belt shaft 212. As shown, capstan 204 may rotate in an extraction direction, removing tape 218 from tape actuation mechanism 102, or in a payout direction, allowing tape 218 to enter tape actuation mechanism 102. As shown in this example, removal of the strap 218 from the strap actuation mechanism 102 will cause the associated pulley sets (sliders and cords) to contract, shortening the strap spans between the sliders in the strap actuation mechanism 102. Paying out the strap 218, or allowing the strap 218 into the strap actuation mechanism 102, may cause the strap actuation mechanism 102 to expand, or the distance of the span in the strap actuation mechanism 102 may increase.

In some embodiments, bevel gear 208 is connected to idler shaft 206 via a one-way locking bearing that allows rotation between idler shaft 206 and the bevel gear in one direction, but prevents rotation between idler shaft 206 and the bevel gear in a second direction. For example, when capstan 204 (and likewise idler shaft 206) is rotated in the extraction direction to retract strap 218 from strap actuation mechanism 102, a one-way locking bearing in the bevel gear may engage, causing the bevel gear to rotate with the idler shaft. In this way, when the capstan rotates in the extraction direction, capstan 204 drives the belt shaft via idler shaft 206, bevel gear 208, and ring gear 210.

In the example shown, the strap 218 passes through the strap actuation mechanism 102 such that both ends of the strap 218 are located in the strap drive mechanism 101. A first end of the strip 218 may be connected to an electrical connector 216 that may be used to monitor an electrical parameter associated with the strip 218 (e.g., continuity, resistance, capacitance, reflectance measurements of support structures within the strip 218, etc.). A second end of the strap 218 may be attached to a strap shaft 212 that may be wound and unwound to receive portions of the strap 218 as the strap is withdrawn from the strap actuation mechanism 102. In some embodiments, the strap 218 in the strap driven system may include internal wiring or circuitry, or be configured to have electrical characteristics that vary under load. For example, the strip as a whole often has a conductive reinforcing structure. In this example, the strap actuation system may perform a continuity check, measure the impedance or resistance between one or more ends of the conductive reinforcing structure, and thus determine whether they have broken and compromised the structural integrity of the strap 218. In another example, the continuity between the inner conductive material of the strip 218 and the housing of the drive mechanism may be measured. The continuity between the inner conductive material of the strap 218 and the housing may indicate that a portion of the strap 218 is worn or damaged and that the strap 218 should be replaced or repaired. In some embodiments, the strips 218 comprise materials having different electrical properties under different loads. For example, as the tension in the strap 218 increases, its resistance or impedance also increases. Electrical connections may be provided at one or both ends of the strap 218 to allow measurement of one or more electrical characteristics that may be used to determine the state (e.g., tension, temperature, configuration, etc.) of the strap 218.

Fig. 3 depicts a left side view of the tape drive mechanism 101. For simplicity, various structural components are not shown. The belt shaft 213 is mounted to the inner hub 302. In some embodiments, the inner hub 302 and the strap shaft 213 are frictionally engaged such that if the frictional force between the inner hub 302 and the strap shaft 213 is overcome, the strap shaft 213 may rotate about the inner hub 302. In some embodiments, the belt shaft 213 is spring biased to the wear surface of the inner hub 302. The inner hub 302 may be mounted on the stationary shaft via a one-way locking bearing, which may be similar to or different from the one-way locking bearing of the reference bevel gear 208 above. When the belt shaft 213 is rotated in the winding direction by the drive of the ring gear 210, the inner hub may rotate with the belt shaft 213, minimizing friction and allowing the belt shaft to be wound in the strap 218. During payout operations, when capstan 204 rotates in the payout direction, bevel gear 208 is free to revolve, independent of idler shaft 206, and allows belt shaft 212 to rotate in the unreeling direction. If the spool 212 were to accumulate a significant amount of angular momentum in the unwinding direction, the spool would continue to pay out the tape 218 after the winch stops rotating, thus introducing slack into the system, potentially causing the tape drive mechanism 101 to lose control or other problems. To ensure that the belt shaft 213 stops when the capstan 204 stops, the inner hub 302 and its associated one-way bearing are locked to the central shaft, preventing the inner hub 302 from rotating. During payout, the belt shaft 213 rotates about the inner hub 302, and tension in the strap 218 overcomes friction between the belt shaft 213 and the inner hub 302.

Also shown in fig. 3 is an anchor 304 that secures one end of the strap 218 to the strap drive mechanism 101. The anchors are located at the high tension end of the strap 218 and provide a fixed reference point for the strap 218 within the strap drive mechanism 101. The strap 218 passes from the anchor 304 over the tension sensor 306 and into the strap actuation mechanism 102. The path of the tape through the tape drive mechanism 101 and the tape actuation mechanism 102 will be described in more detail below in connection with fig. 4.

Still referring to fig. 3, in some embodiments, the tape drive mechanism 101 includes an encoder wheel 326. The encoder wheel 326 may have bumps or protrusions on its outer surface that are configured to mate with grooves or channels in the strap 218, ensuring that the strap 218 does not slide over the encoder wheel 326. The encoder wheel 326 may be mounted to an encoder that may provide an indication of the precise position of the encoder wheel 326, and thus the strap 218. The strap actuation mechanism 102 may have a position directly associated to the strap position. For example, where the strap actuation mechanism 102 is part of a linear actuator, the distance that the actuator has expanded or contracted may be determined directly from the encoder position.

The tension sensor 306 as shown in fig. 3 may have a pulley that redirects the strap 218. As the pulley on the tension sensor 306 redirects the belt 218, a reaction force is generated on the pulley that is proportional to the tension in the belt 218. The pulley may be affixed to a translating member (e.g., a piston or cylinder) that is biased against the reaction force by a spring. In this configuration, as the tension in the strap 218 increases, the reaction force will increase, compressing the spring and translating the pulley (upward in the drawing provided in fig. 3). The position indicators on the translating member may measure the translation of the pulley and translating member, which is proportional to the tension in the strap 218. The position indicators may be electronic (e.g., one or more hall effect sensors, or strain gauges) or mechanical (e.g., colored or engraved position indicators). The tension sensor 306 may be used to automatically act safely (e.g., emergency payout) or calculate expected wear and determine the service life of the strap 218 or the strap drive.

Fig. 4 depicts the strap 218 of the strap drive mechanism 101 and the strap actuation mechanism 102. Referring to fig. 2-4, the first end 402 of the strap 218 may be connected to an electrical connector (e.g., the strap connector 206 described with reference to fig. 2) and mounted to a circuit board or other device within the strap drive mechanism 101. The strap 218 may then be passed through the anchors forming the high friction anchor bends 404, ensuring that the first end 402 of the strap 218 is not under tension, and that the strap 218 is secured around the anchor bends 404. The strap 218 may then be passed through a tension sensor (such as tension sensor 306 depicted in fig. 3) to form a tension sensor bend 406.

The strap 218 then enters the strap 218 actuation mechanism at the strap actuation mechanism entrance 408. The illustrated example depicts the strap 218 passing through a trolley system with several free spans within the strap drive mechanism. The strap 218 then returns to the strap drive mechanism via strap actuation mechanism return 410 where the strap passes around the capstan and idler axes, causing one or more bends around both the capstan axis 412 and the idler axis 414. Following its last turn about capstan axis 412 and idle axis 414, ribbon 218 passes into ribbon spool winding 416 where it is wound or unwound depending on the operation of the ribbon drive mechanism. The second end 418 may terminate the strap 218 and be attached to the strap shaft.

Fig. 5 depicts a cut-away view of the tape drive mechanism 101, including a fixed tape and a tension roller that may be used as a slack removal device. In some tape driven systems, it is desirable to minimize sag in the system. In other words, the strap 218 or a portion of the strap 218 is preferably always under tension. In a system with two shafts, one being a power shaft and one being a shaft driven by the strap 218 (e.g., winch and idler shaft), a system for ensuring positive (greater than zero) tension in the strap 218 may be provided. A first retaining device, such as a strap or roller, may force strap 218 against a portion of the capstan, ensuring traction between the capstan and strap 218, regardless of strap tension. The second retaining means may apply pressure to the strip 218 on the idle shaft and ensure positive (greater than zero) contact with the idle shaft. In this way, in the event of slack, the winch may withdraw the slack from between the first and second holding means and thus ensure that the winch rotates with lost motion to remove any remaining slack in the system.

The slack in the ribbon drive mechanism of the main ribbon 218 can cause problems during operation. For example, the slack strap 218 may fall off one or more pulleys, or fold over itself, causing jams and jamming of the strap drive mechanism. In addition, the slack or loose strap 218 may reduce friction or traction between the winch and the strap 218, resulting in the winch not being able to move the strap 218. In this case, the idle shaft may not rotate in unison with the capstan because positive friction cannot be ensured.

Still referring to fig. 5, the retention strap 502 may be a strap separate from the main strap 218 of the strap drive mechanism and may be under a predetermined tension and positioned to apply a force to one or more turns of the main strap 218 on the capstan 204. In some embodiments, the retention strap 502 applies pressure to the least tensioned loop of the main strap 218 on the winch 204. This pressure ensures positive contact and thus traction between the main strap 218 and the winch 204, even when the main strap 218 is in a relaxed state. In addition to securing the strap 502, the tensioning roller 504 may be positioned to apply pressure to one or more turns of the strap 218 on the idler shaft 206, ensuring positive contact of the strap 218 with the idler shaft at the tensioning roller 504. In the event that the primary strap 218 is loose or slack is present, it may be ensured that the winch 204 can rotate and draw slack from the span between the winch 204 and the tension roller 504, as the retention strap 502 ensures traction for a portion of the winch 204. Once slack is removed from the span between winch 204 and tension roller 504, idler shaft 206 will begin to rotate via main strap 218, and thus slack may be withdrawn from the remainder of the system.

Fig. 6 depicts a cross-sectional view of a portion of the tape drive mechanism 101 shown in fig. 1, including a self-winding mechanism 600. The idler shaft 206 may rotate about an idler axis 414 in a draw-out direction or payout direction and is driven by the strap 218 via a winch. Bevel gear 208 is connected to idler shaft 206 via one-way bearing 604A. The one-way bearing 604A allows rotation between the bevel gear 208 and the idler shaft 206 when the idler shaft rotates in the payout direction relative to the bevel gear 208. The one-way bearing 604A prohibits rotation in the extraction direction between the idler shaft 206 and the bevel gear 208. Although shown as bevel gears 208, any suitable gear type or one-way locking mechanism may be used. Bevel gear 208 engages a ring gear 210 that is in frictional contact with a belt shaft 212. The spring 608A ensures positive engagement between the ring gear 210 and the belt shaft 212. The belt shaft 212 is frictionally engaged with the inner hub 302. The inner hub 302 and the belt shaft 212 may be pressed together by a spring 608B. A wear surface (e.g., a brake pad, or friction disc) may be provided between the belt shaft 212 and the inner hub 302, which may ensure that a desired level of friction is achieved between the inner hub 302 and the belt shaft 212. The inner hub 302 may be mounted to a hub axle 606 via a one-way locking bearing 604B. The one-way locking bearing 604B allows the inner hub 302 to rotate about the hub axle 606 in the winding direction (as indicated by the arrow on the tape axle axis 610), but inhibits rotation of the inner hub 302 about the hub axle 606 in the payout direction.

The self-winding mechanism has two functions. It ensures that tension is maintained in the tape 218 as the tape 218 is wound around the spool during the extraction operation of the tape drive mechanism (e.g., tape drive mechanism 101 as shown and described with reference to fig. 2). The self-winding mechanism also maintains tension in the strap 218 during the payout operation.

During an extraction operation, the tape drive mechanism withdraws the tape 218 from a tape actuation mechanism (e.g., tape actuation mechanism 102 of fig. 1). Idler shaft 206 rotates about idler axis 414 and engages with one-way lock bearing 604A, which rotates bevel gear 208 with idler shaft 206. The extraction direction is indicated by the arrow on the idle axis 414.

As the bevel gear 208 rotates, it drives the ring gear 210, the ring gear 210 applies a torsional force to the belt shaft 212 to rotate the belt shaft 212 about the belt shaft axis 610 in the winding direction. The winding direction is indicated by the arrow on the tape spool axis 610. As the spool 212 rolls in more and more strips 218, the effective diameter of the spool 212 increases as the strips 218 overlap. For a constant extraction rate of the tape drive mechanism, the tape shaft 212 must be slowed down. In other words, the rotation rate of the belt shaft 212 must be faster when the belt shaft 212 is empty than when the belt shaft 212 is full. To compensate for this shift requirement of the belt shaft 212, the ring gear 210 is not directly attached to the belt shaft 212, but rotates along the side of the belt shaft 212, transmitting frictional forces. The gearing between the bevel gear 208 and the ring gear 210 may be selected such that the ring gear will overspeed the belt shaft 212 (e.g., rotate faster than the belt shaft) over the entire range of operation of the belt shaft 212. In some embodiments, the ring gear 210 overruns the belt shaft by 1.5% when the belt shaft 212 is empty and by 15% when the belt shaft 212 is full. The overrun ring gear 210 ensures that the belt shaft 212 applies tension to the strap 218 throughout the extraction operation.

During the extraction operation, when the belt shaft 212 rotates in the winding direction, the inner hub 302 is free to rotate about the hub axle 606. The belt shaft 212 rotates with the inner hub 302.

Tension in the strap 218 must still be maintained during the payout operation. During payout, idler shaft 206 rotates in the payout direction (opposite the indicated arrow on idler axis 414) and one-way bearing 604A disengages, allowing idler shaft 206 and bevel gear 208 to rotate independently. This allows the idler shaft 206 and the belt shaft 212 to rotate at different speeds as needed for the payout of the tape 218 from the belt shaft 212. The one-way bearing 604B engages prohibiting rotation of the inner hub 302 in the unreeling direction (opposite the indicated arrow on the tape shaft axis 610). The tension strap shaft in the strap 218 pulls the strap shaft 212 around the inner hub 302, overcoming friction between the inner hub 302 and the strap shaft 212. Because the spool must overcome friction to rotate in the payout direction, it ensures that tension in the strap 218 is maintained during the payout operation. In some embodiments, the ring gear 210 and bevel gear 208 rotate with the belt shaft 212 because the one-way bearing 604A is disengaged.

Fig. 7A and 7B depict a manually operated crane showing another embodiment of a strap drive mechanism. Crane 700 may include boom 704 and load block 706 that form a strap actuated mechanism 702. In this embodiment, the strap actuated lifting mechanism 702 is a lifting device. Crane 700 may be operated with a self-wrapping tape drive 701. In this embodiment, the strap drive mechanism 701 is manually operated by a hand crank 708. In this embodiment, mechanical advantage may be provided to the user based on the diameters of the winch and hand crank handles, and optionally one or more trolley (block and tackle) systems housed within boom 704 (not shown). Fig. 7B shows an enlarged view of the tape drive mechanism 701 with various structural components removed for simplicity. Similar to the strap drive mechanism 101, a winch 710, strap 712, strap shaft 714, and idler shaft 716 are shown.

In some embodiments, multiple strap drive mechanisms 101, or different configurations of strap actuation mechanisms 102, may be provided to accommodate bi-directional application of motive force (e.g., providing expansion and contraction of the motive force). For example, a pair of trolley systems may be coupled together and configured to operate in opposition to each other (e.g., one strip pays out while another is pulled in). Providing both powered expansion and contraction of the linear actuator.

Although shown as having a rectangular cross-section throughout, the strap 218 may be any suitable shape. For example, the strips 218 may have a square, triangular, trapezoidal, or any combination of these cross-sections. In some embodiments, a portion of the strap 218 may have a trapezoidal cross section, while another portion may be triangular. The present disclosure is not limited thereto. Further, the strap 218 may be constructed of any suitable material, such as woven steel, kevlar, rubber, leather, or a combination of these.

Although the rewind mechanism has been described as having an angled idle shaft and a belt shaft attached to the side of the belt drive mechanism, in some embodiments the belt shaft may be on top of or below the belt drive mechanism. In some embodiments, the idler shaft may protrude from the rear of the tape drive mechanism and rotate the tape shaft away from the tape drive mechanism.

The foregoing description is provided in the context of one or more specific embodiments. Various modifications, alterations and permutations of the disclosed embodiments may be made without departing from the scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown or described, but is to be accorded the widest scope consistent with the principles and features of the disclosure.

Claims

1. A self-winding tape drive mechanism comprising:

a capstan configured to withdraw a strap from, or pay out a strap to, a strap actuation system;

an idler shaft coupled to the winch via the strap, wherein the idler shaft is configured to rotate in an extraction direction when the winch rotates in a direction to extract the strap, and wherein the idler shaft is configured to rotate in a payout direction when the winch rotates in a direction to payout the strap, the idler shaft comprising:

a first end configured to accept one or more turns of the strap;

a second end coupled to the first one-way locking bearing;

a first gear connected to the first one-way lock bearing, wherein the first one-way lock bearing is engaged when the idle shaft rotates in the extraction direction, causing the first gear to rotate with the rotating idle shaft, and wherein the one-way lock bearing is disengaged when the idle shaft rotates in the payout direction, allowing relative rotation between the first gear and the idle shaft; and

a spool configured to receive or pay out a portion of the strap, the spool comprising:

an outer hub configured to rotate about an outer circumference of the outer hub and to wind or unwind the portion of the strap; and

a second gear in frictional engagement with the outer hub, wherein the second gear is configured to be driven by the first gear such that the first gear drives the second gear, resulting in rotation of the outer hub in a direction to wind the portion of the ribbon when the idler shaft is rotated in the extraction direction.

2. The strap drive mechanism of claim 1, wherein the strap package is connected to an inner hub of a central shaft via a second one-way locking bearing, wherein the second one-way locking bearing allows the inner hub to rotate relative to the central shaft when the outer hub rotates in a direction to wind the portion of the strap, wherein the second one-way locking bearing prevents rotation between the inner hub and the central shaft when the outer hub rotates in a direction to unwind the portion of the strap, and wherein the inner hub frictionally engages the outer hub such that the outer hub overcomes frictional forces between the inner hub and the outer hub to rotate relative to the inner hub when rotating in a direction to unwind the portion of the strap.

3. The tape drive mechanism of claim 1, wherein the first gear is a bevel gear and wherein the second gear is a ring gear.

4. The tape drive mechanism of claim 1, wherein the second gear is configured to overspeed the outer hub at least 1.5% faster than the outer hub.

5. The tape drive mechanism of claim 1, wherein the tape passes through the tape actuation system and back to the tape drive mechanism such that both the first and second ends of the tape are within the tape drive mechanism; wherein extraction and payout of the strip actuates the strip actuation system.

6. The strap drive mechanism of claim 5, wherein the strap actuation system comprises a sled set that expands or contracts as the strap is extracted from or paid out to the strap actuation system.

7. The tape drive mechanism of claim 5, wherein at least one end of the tape is electrically connected to an electrical circuit in the tape drive mechanism, and wherein the electrical circuit measures at least one electrical parameter associated with the tape.

8. The tape drive of claim 1, comprising an encoder wheel having an outer surface with ribs, wherein the ribs engage grooves in the tape, and wherein a shaft of the encoder wheel is connected to an encoder.

9. A self-winding tape drive mechanism comprising:

a first end configured to accept one or more turns of the strap;

a second end coupled to the first one-way locking bearing;

an outer hub configured to rotate around an outer circumference of the outer hub and to wind or unwind portions of the strap; and

an inner hub connected to a central shaft via a second one-way locking bearing, wherein the second one-way locking bearing allows the inner hub to rotate relative to the central shaft when the outer hub rotates in a direction to wind the portion of the strap, wherein the second one-way locking bearing prevents rotation between the inner hub and the central shaft when the outer hub rotates in a direction to unwind the portion of the strap, and wherein the inner hub frictionally engages with the outer hub such that the outer hub overcomes a frictional force between the inner hub and the outer hub to rotate relative to the inner hub when rotating in a direction to unwind the portion of the strap.

10. The strap drive mechanism of claim 9, wherein the strap shaft includes a second gear in frictional engagement with the outer hub, wherein the second gear is configured to be driven by the first gear such that the first gear drives the second gear, resulting in rotation of the outer hub in a direction to wind the portion of the strap when the idler shaft is rotated in the extraction direction.

11. The tape drive mechanism of claim 9, wherein the first gear is a bevel gear and the second gear is a ring gear.

12. The tape drive mechanism of claim 9, wherein the second gear is configured to overspeed the outer hub at least 1.5% faster than the outer hub.

13. The tape drive mechanism of claim 9, wherein the tape passes through the tape actuation system and back to the tape drive mechanism such that both the first and second ends of the tape are within the tape drive mechanism; wherein extraction and payout of the strip actuates the strip actuation system.

14. The strap drive mechanism of claim 13, wherein the strap actuation system comprises a sled set that expands or contracts as the strap is extracted from or paid out to the strap actuation system.

15. The tape drive of claim 13, wherein at least one end of the tape is electrically connected to an electrical circuit in the tape drive, and wherein the electrical circuit measures at least one electrical parameter associated with the tape.

16. The tape drive of claim 9, comprising an encoder wheel having an outer surface with ribs, wherein the ribs engage grooves in the tape, and wherein a shaft of the encoder wheel is connected to an encoder.

17. A self-winding tape drive mechanism comprising:

a first end configured to accept one or more turns of the strap;

a second end coupled to the first one-way locking bearing;

an outer hub configured to rotate about an outer circumference of the outer hub and to wind or unwind the portion of the strap;

an inner hub connected to a central shaft via a second one-way locking bearing, wherein the second one-way locking bearing allows the inner hub to rotate relative to the central shaft when the outer hub rotates in a direction to wind the portion of the strap, wherein the second one-way locking bearing prevents rotation between the inner hub and the central shaft when the outer hub rotates in a direction to unwind the portion of the strap, and wherein the inner hub frictionally engages with the outer hub such that the outer hub overcomes a frictional force between the inner hub and the outer hub to rotate relative to the inner hub when rotating in a direction to unwind the portion of the strap; and

18. The tape drive mechanism of claim 17, wherein the first gear is a bevel gear and the second gear is a ring gear, and wherein the ring gear is configured to overspeed the outer hub at least 1.5% faster than the outer hub.

19. The tape drive of claim 17, comprising an encoder wheel having an outer surface with ribs, wherein the ribs engage grooves in the tape, and wherein a shaft of the encoder wheel is connected to an encoder.

20. The tape drive mechanism of claim 17, wherein the tape passes through the tape actuation system and back to the tape drive mechanism such that both the first and second ends of the tape are within the tape drive mechanism; wherein extraction and payout of the strip actuates the strip actuation system.