WO2020061624A1

WO2020061624A1 - A clutch

Info

Publication number: WO2020061624A1
Application number: PCT/AU2019/051026
Authority: WO
Inventors: Ralph Sarich; Mitchell Cowling; Harley Olsthoorn; Kim Schlunke
Original assignee: Cape Bouvard Technologies Pty Ltd
Priority date: 2018-09-27
Filing date: 2019-09-25
Publication date: 2020-04-02
Also published as: TW202024501A; WO2020061645A1; TW202021862A

Abstract

The present invention provides a clutch (11) which is moveable between an engaged condition and a disengaged condition. The clutch comprises an output member (29) which is selectively connected to an input member (31) wherein the axial distance between the output member and the input member is fixed. The clutch also comprises an engagement means which is adapted to move from a first position to a second position and an activation means. When the engagement means is in the first position the clutch is in the disengaged condition, whereupon activation of the activation means the engagement means moves to the second position to fix the output member relative to the input member such that the clutch is in the engaged condition.

Description

A Clutch

TECHNICIAL FIELD

[0001 ] The present invention generally relates to a clutch, in particular the invention relates to a clutch having a fixed width.

BACKGROUND ART

[0002] Transmission systems are used in various vehicles and industrial equipment to provide controlled application of power from an input to an output. These systems typically use a number of gears as well as one or more clutches, to control the application of power from the input to the output.

[0003] Transmission systems are configured to provide a required output(s) of a given input. This may result in controlling the application of power from the input to provide slower output speeds at a high torque, or to provide higher output speeds.

[0004] The purpose of a clutch in a transmission system is to connect and disconnect two rotating shafts, such that when the clutch is engaged, the rotation of an input shaft is transferred to an output shaft, whereupon disengagement of the clutch, rotation of each shaft is independent of each other. Clutches typically work by axial movement of one component relative to another component whereupon the components frictionally engage or interlock to transfer motion therebetween. The space required to allow the axial movement can be problematic to accommodate, particularly in small transmission systems.

[0005] A transmission system typically provides multiple gear ratios, depending on the number of gears, as well as a means to shift between those ratios to provide variations in speed and/or direction.

[0006] Considering a bicycle, its transmission system typically incorporates a centrally located chain ring to which is fixed two crank arms. The chain ring is spaced from a rear sprocket set with a chain/belt spanning therebetween. A rider engages the crank arms to provide the input and rotate the chain ring. As a result of the riders input torque is exerted on the chain ring and transferred to the rear sprocket through the chain. This causes the rear sprocket to rotate. The rear sprocket set is secured to the axle of the rear wheel of the bicycle such that rotation of the rear sprocket set translates to rotation of the rear wheel.

[0007] To control the application of force from the rider to the rear wheel the transmission system provides a gearing system. The gearing system enables the rider to shift gears and therefore control the effect the rider’s input has on the rear wheel. This gear system generally comprises a number of co-axiaily mounted rear sprockets of varying diameter and a number of co-axially mounted chain rings also of different diameter. By shifting gears the rider can cause the chain to move to different combinations of sprockets or chain rings, enabling the rider to choose the gear ratio which best suits the conditions.

[0008] The gearing system typically incorporates a derailieur which is caused to move and guide the chain of the bicycle to a different sprocket in order to provide a different gear ratio. Where the bicycle has multiple rear sprockets as well as multiple chain rings the bicycle will have a derailieur dedicated to each set.

[0009] While the use of derailleurs with respect to bicycles is widespread they are not without their problems. With current bicycle transmission systems, the derailleurs can dislodge the chain during gear changes and can cause difficulties when shifting gears (up or down).

[0010] Furthermore, most combinations of gears result in the chain being positioned in a plane which is at an angle to the plane of the chain ring and/or the plane of the rear socket to which the chain is engaged. This significantly reduces the efficiency of the bicycle transmission system as well as making it impractical for all gear ratios to be utilised. In fact straight-line chain setting, which provides the greatest efficiency, is only achievable for a small number of gear settings of the bicycle transmission system.

[0011 ] The typical gearing system on a bicycle requires the operator to manually adjust a lever in order to change the gears. This therefore relies on the rider knowing exactly when the best time to shift gears is. The optimum point to shift gears is a challenge even for seasoned riders let alone those with little or no experience !n most cases, riders find it inconvenient having to continually select gears and/or do not change gears when appropriate resulting in a reduction in speed and efficiency.

[0012] In addition, derailleur transmissions are exposed to the environment, facilitating contamination, which in turn reduces their effective service life and increases maintenance and risk of failure. For optimal operation the derailieurs require frequent adjustment and lubrication to ensure the chain is guided to the correct gear when shifting gears.

[0013] An additional disadvantage of derailleur transmissions is that the process of shifting gears results in a temporary loss of power transmission while the chain relocates. This results in a loss of rider input, particularly when riding uphill, as the resulting loss of momentum requires additional effort to bring the bicycle back to the speed before the gear shift.

[0014] Derailleur transmissions are also sensitive to physical shocks to the bike, lack of mechanical alignment, componentry mismatch, and incorrect operation by the rider. These factors can lead to dislodgment of the chain and a general inefficiency in converting the rider’s energy to motion of the bicycle.

[0015] The above discussion of the background art is intended to facilitate an understanding of the present invention only. While the discussion focusses on transmission systems of bicycles, it would be readily understood that similar problems exist in transmission systems used in other applications. SUMMARY OF INVENTION

[0016] It is an object of this invention to provide a clutch which ameliorates, mitigates or overcomes, at least one disadvantage of the prior art, or which will at least provide the public with a practical choice.

[0017] The present invention provides a clutch which is moveable between an engaged condition and a disengaged condition, the clutch comprising an output member which is selectively connected to an input member, wherein the axial distance between the output member and the input member is fixed; an engagement means which is adapted to move from a first position to a second position; and an activation means; wherein when the engagement means is in the first position the clutch is in the disengaged condition, whereupon activation of the activation means the engagement means moves to the second position to fix the output member relative to the input member such that the dutch is in the engaged condition.

[0018] The output member and the input member may be fixed relative to each other when selectively connected, and may rotate freely with respect to each other when not selectively connected.

[0019] The output member and input member may be coaxially mounted wherein the output member and input member rotate independent of each other when the clutch is the disengaged condition, and are rotatably fixed relative to each other when the clutch is the engaged condition.

[0020] The output member and input member may be coaxially mounted on an output shaft. The output member may be adapted to be fixed to the output shaft.

[0021 ] The input member may comprise a bearing and may be adapted to be mounted on the output shaft. The input member may be adapted to be connected directly or indirectly to an input shaft.

[0022] The engagement means may comprise at least one engaging portion which selectively fixes the output member relative to the input member.

[0023] !n one aspect of the invention the at least one engaging portion engages with the output member to fix the output member relative to the input member. [0024] In another aspect of the invention the at least one engaging portion engages with the input member to fix the output member relative to the input member.

[0025] The at least one engaging portion may be movable between a retracted position wherein the output member and input member are independent of each other, and an extended position wherein the output member and input member are fixed relative to each other. With this arrangement the output member and input member are positively engaged when the at least one engaging portion is in the extended position.

[0028] The at least one engaging portion may be biased to a retracted position.

[0027] The input member may comprise a receiving portion for receiving the engaging portion.

[0028] Each of the at least one engaging portion may be in the form of a projection which moves between the retracted position and the extended position.

[0029] Each of the at least one engaging portions may be in the form of a paw! pivotally mounted on the output member such that the pawl may pivot between the refracted position and the extended position. There may be one or more pawls.

[0030] The receiving portion of the input member may be in the form of a recess, the recess being adapted to receive an end of the pawl as the pawl moves to the extended position.

[0031 ] There may be two pawls spaced from each other. Preferably the two pawls are spaced to be angularly equidistant from each other. The input member may have at least two recesses spaced equidistant from each other. As would be apparent to a person skilled in the art there may be more than two pawls and more than two recesses. The scope of this specification covers such variations. [0032] Each recess may be configured to retain the pawl therein to fix the output member to the input member

[0033] The recess may be configured to retain the paw! therein to fix the output member to the input member when the rotational speed of the output member is equal to the rotational speed of the input member.

[0034] The recess may be configured to release the pawl when the rotational speed of the input member is greater than the rotational speed of the output member, allowing the output member and input member to rotate independently of each other. .

[0035] Each pawl may be biased to the retracted position when released from the recess. Biasing of the pawl may be caused by springs, magnets or other means as would be readily apparent to a person skilled In the art.

[0038] The activation means may comprise a governor member which is operably connected to the engagement means to move the engagement means between the retracted position and extended position.

[0037] The governor member may be coaxially mounted with the output member and input member.

[0038] The governor member may be pivotally connected to each pawl.

[0039] The governor member may be mounted to the output member such that it is movable between a first angular position, wherein each pawl is in the retracted position, and a second angular position, wherein each pawl is in the extended position.

[0040] Each pawl may have an arm extending therefrom, wherein an end of that arm is secured to the governor member. Each arm may be retained relative to a slot formed in the governor member. Each arm may provide a peg which is received in the respective slot.

[0041 ] In one aspect of the invention the activation means is electronically activated. The activation means may act in a radial orientation relative to the dutch. The activation means may comprise a rotary voice coil which upon activation causes the governor member to move from the first angular position to the second angular position. A rotary voice coil moves in an arc-shaped motion, generating torque with fast response times. It is caused to move/produce torque when a current-carrying conductor is placed in a magnetic field. The amount of torque produced is proportional to the current, while the direction of the current determines the direction of motion. In other variations of the invention, as would be understood by the person skilled in the art, and which fall within the scope of the present invention, the activation means may comprise other actuators which act in a radial manner and which may be electronic and/or mechanical in nature.

[0042] In another aspect of the invention the activation means is mechanically activated. The output member and governor member may be biased by a biasing means, such as a spring extending between the governor member and the output member. Until the force of the biasing means is overcome the governor member remains in its first angular position and the pawls are held in the retracted position.

[0043] The activation means also comprises a plurality of masses secured to the input member. At a predetermined speed the centripetal force generated by the masses counteracts the force of the biasing means to cause the governor member to move to the second angular position causing the pawls to move to the extend position, whereupon engagement of each pawl with its respective recess in the input member fixes the input member relative to the output member.

[0044] The activation means may also comprise a control means to activate the activation means.

[0045] In one aspect the control means may comprise a plurality of sensors which monitor one or more characteristics associated with the clutch. These characteristics may include one or more of the following: linear velocity of the dutch, angular position of the clutch, angular velocity of the output member, angular velocity of the input member. The control means may activate the activation means when the one or more characteristics being monitored reach predetermined values.

[0046] In another aspect of the invention the control means comprises a switch which may be manually operable to activate the activation means.

[0047] The present invention further provides a clutch which is moveable between an engaged condition and a disengaged condition, the clutch comprising an output member which is selectively connected to an input member, wherein the axial distance between the output member and the input member is fixed; an engagement means which is adapted to move from a first position to a second position to fix the output member to the input member; and an activation means; wherein the clutch is in the disengaged condition when the engagement means is in the first position, whereupon activation of the activation means the engagement means moves to the second position to fix the output member relative to the input member whereby the clutch is in an engaged position.

[0048] The present invention further provides a clutch which is of fixed width and is moveable between an engaged condition and a disengaged condition, the dutch comprising an output member; an input member which is selectively fixed to the output member; an engagement means which is adapted to move from a first position to a second position to fix the output member to the input member; and an activation means; wherein the dutch is in the disengaged condition when the engagement means is in the first position, whereupon activation of the activation means the engagement means moves to the second position to fix the output member relative to the input member whereby the clutch is in an engaged position The present invention further provides a dutch comprising: a first member adapted to be fixed relative to an input; a second member adapted to be selectively fixed to the first member, the second member providing an output; an engagement means to engage the first member relative to the second member; an activation means to activate the engagement means between an engaged position, wherein the clutch is in an engaged condition and a disengaged position wherein the clutch is in a disengaged condition; whereupon activation of the engagement means the clutch is in the engaged condition such that the first member is fixed to the second member to transfer the input to the output, whereupon the engagement means moving to the first condition the clutch is in the disengaged condition such that the first member is independent of the second member, the width of the clutch remaining constant as it moves between its engaged condition and disengaged condition. The present invention further provides a clutch comprising: an output member which is selectively connected to an input member, the axial distance between the output member and the input member being fixed; an engagement means which is adapted to move from a first position to a second position; and an activation means; wherein when the engagement means is in the first position the dutch is in a disengaged condition, whereupon activation of the activation means the engagement means moves to the second position to rotationai!y fix the output member to the input member such that the clutch is in an engaged condition.

[0051 ] The present invention further provides a transmission system comprising one or more clutches as herein before described.

[0052] The present invention further provides a bicycle transmission system comprising one or more clutches as herein before described, wherein the output member is mounted on the crank shaft which supports the crank arms, and the input member is connected to the rear sprocket of a rear wheel of the bicycle by a chain which passes through a series of gears.

[0053] The present invention further provides a clutch which is moveable between an engaged condition and a disengaged condition, the dutch comprising an output member which is selectively connected to an input member; an engagement means which is adapted to move from a first position to a second position to fix the output member to the input member; and an activation means; wherein the clutch is in the disengaged condition when the engagement means is in the first position, whereupon activation of the activation means the engagement means moves to the second position to fix the output member relative to the input member whereby the clutch is in an engaged position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Further features of the present invention are more fully described in the following description of several non-limiting embodiments thereof. This description is included solely for the purposes of exemplifying the present invention. It should not be understood as a restriction on the broad summary, disclosure or description of the invention as set out above. The description will be made with reference to the accompanying drawings in which:

Figure 1 is an exploded view of a clutch according to a first

embodiment of the present invention;

Figure 2 is a front assembled view of the dutch of figure 1 in a disengaged condition;

Figure 3 is a front assembled view of the clutch of figure 1 in an engaged condition;

Figure 4 is a view similar to figure 3 but with a magnet and faceplate removed;

Figure 5 is a detailed view of a paw! when the clutch is in an engaged condition;

Figure 8 is a schematic of a control system;

Figure 7 is a bicycle incorporating a transmission system which comprises two dutches according to the first embodiment;

Figure 8 is a perspective view of the transmission system shown in figure 7;

Figure 9 is an exploded view of a dutch according to a second embodiment of the present invention;

Figure 10 is a front assembled view of the clutch of figure 1 in a disengaged condition;

Figure 11 is a front assembled view of the clutch of figure 1 in an engaged condition; and

Figure 12 is side view of a dutch according to a third embodiment of the present invention. [0055] In the drawings like structures are referred to by like numerals throughout the several views. The drawings shown are not necessarily to scale, with emphasis instead generally being placed upon illustrating the principles of the present invention.

DESCRIPTION OF EMBODIMENTS

[0056] The clutch of the present invention is advantageous in its construction and configuration when compared to prior art clutches. In particular the present clutch of the present embodiment remains of a fixed width regardless of whether the clutch is engaged or disengaged. As a result the clutch does not require any additional space to accommodate changes in width which would otherwise be required. An output member and an input member are axially fixed relative to each other, allowing the clutch to be utilised in applications where space is limited. This is achieved by providing a means whereby the output member and input member are able to positively engage each other through radial movement of an engagement means.

[0057] In addition, according to an embodiment, the clutch is able to operate automatically when predetermined parameters are met. This removes the need for an operator to operate the clutch, allowing for the clutch to disengage and engage at the most optimum time according to the required application.

As discussed below, the clutch may be associated with a control means 53, which may be electronic in operation, for causing the operation of the clutch.

[0058] Referring to figures 1 to 8, the invention according to a first

embodiment is in the form of a clutch 11. In one application the clutch 11 is deployed in a transmission system 13 for a bicycle 15.

[0059] While an example application is in relation to a bicycle, the present invention is not limited to such an application as there are many more applications in many other types of driven equipment. These include applications in vehicles, motorcycles, and industrial equipment. Other applications as would be understood by the person skilled in the art are considered to be within the scope of this invention. [0080] Referring to figures 7 and 8, the transmission system 13 is located adjacent an input shaft 17 of the bicycle 15. The input shaft 17 supports a chain ring and crank arms 19 of the bicycle. The clutch 11 is mounted on an output shaft 21. The output shaft 21 provides a drive sprocket 23. The bicycle comprises a chain 25 which extends from the drive sprocket 23 to a rear sprocket 27 fixed to the rear wheel. When the clutch 11 is engaged, rotation of the input shaft 17 resulting from a rider pedaling translates, via the transmission system 13, to rotation of the drive sprocket 23, which in turn rotates the rear sprocket 27 through the chain 25. While not described herein, the transmission system 13 is configured to provide different gear ratios to control the transfer of power from the input (rider) to the output (rear wheel).

[0061 ] The clutch 11 comprises an output member 29, which is fixed to the output shaft 21 , and an input member 31 which is mounted on the output shaft

[0082] The input member 31 is disc like in shape and comprises a bearing 33 such that the input member 31 is able to rotate independently of the output shaft 21 when mounted thereon. The input member 31 also comprises four recesses 35 spaced equidistance around the periphery of the input member 29 such that an opening of each recess 35 opens inwardly away from the periphery of the input member 31 , for reasons which will be described below.

[0063] The clutch 11 also comprises an engagement means which moves between a first position whereby the output member 29 and input member 31 are free to rotate independent of each other, and a second position whereby the output member 29 and input member 31 are fixed relative to each other. The engagement means provides engaging portions, which in this

embodiment are in the form of two pawls 37.

[0084] Each pawl 37 is pivotally mounted on the output member 29 to move from a retracted position (as shown in figure 2) to an extended position (as shown in figure 3). Each pawl 37 has an end 39 distal from where the pawl is mounted which is adapted to be received in the recess 35 of the input member 31 when in the extended position. Each pawl also provides an arm 41 which extends away from the pawl at a position along its length, for reasons which will be described below.

[0065] The clutch 11 also comprises an activation means, which in this embodiment is electronic in nature. The activation means comprises a governor member 43 which is co-axially mounted with respect to the input member 31 and output member 29. The governor member 43 is limited to angular movement between a first angular position (as shown in figure 2) and a second angular position (as shown in figure 3).

[0066] The governor member 43 provides two slots 51 which, in the present embodiment, extend radially outward from the center of the output shaft 21. Once assembled each slot 51 receives a peg (not shown) extending from an underside of the arm 41 of each pawl 37. Each slot 51 restricts movement of the peg along the slot to govern the movement of each pawl 37.

[0067] The activation means also comprises a rotary voice coil 45 which directly acts to cause angular movement of the governor member 43.

[0068] The voice coil 45 comprises two magnets 47 secured to the output member 29 in a spaced apart relation. The voice coil 45 comprises a copper coil 49 which is fixed to the governor member 43 and is received between the magnets 47 when the clutch 11 is assembled.

[0069] In operation the activation means is associated with the control means 53 which reacts to certain conditions to determine when the activation means is required to be activated. According to this embodiment and as shown in figure 6 the control means 53 comprises two speed sensors 55, an

inclinometer 57, a power supply 59 and a microprocessor 61. The

microprocessor 61 can be programmed such that at predetermined values the microprocessor 61 causes activation of the activation means by pulsing the voice coil 45. Figure 6 shows two voice coils. The second voice coil is associated with a second clutch which may be included in the transmission system 13. In other embodiments the control means 53 may comprise one or more sensors. These sensors may be selected to measure a variety of properties associated with the transmission system 13. Furthermore the transmission system according to other embodiments may comprise one, two or more clutches 11. Furthermore the transmission system 13 of other embodiments may incorporate other type of clutches along with at least one clutch 11 according to the present invention. Such variations are considered to fail within the scope of the present invention.

[0070] In the application of a bicycle, the clutch 11 is initially in a disengaged condition. The transmission system 13 incorporates a sprag clutch (not shown) which, at low speeds, transfers the rotation of the input shaft caused by pedaling to the output shaft 21 to rotate the drive sprocket 23. This causes the chain 25 to rotate the rear sprocket 27. In this configuration the output member 29 rotates with the output shaft 21 while the input member 31 is able to rotate independent of the output member 29.

[0071 ] When certain criteria are met, such as when the bicycle 15 reaches a predetermined velocity, as monitored by the sensors of the control means 53, the control means 53 causes activation of the activation means by pulsing the voice coil 45. This causes angular movement of the governor member 43. As the governor member 43 rotates the arm 41 is forced to move along the slot 51 to extend the pawls 37 from their retracted condition towards their extended condition. As the output member 29 is rotating relative to the input member 31 the end 39 of the pawl will align with the recess 35 in the input member 31 , when the end of the pawl extends sufficiently the end of the pawl will be received in the recess 35 to positively engage the input member 31 and fix the input member 31 relative to the output member 29 so that the input member 31 and the output member 29 rotate in the same direction at the same velocity

[0072] The pawls 37 will remain in their extended position to positively engage the input member, fixing the output member relative to the input member until either the input member 31 is caused to rotate faster than the output member (over run), or the force is removed from the output member 29. When either of these events take place the force maintaining the pawls in the recesses 35 is removed and the pawls 37 are able to return to their retracted position, allowing the input member 31 to rotate independently of the output member 29. When this occurs the dutch returns to its disengaged condition.

[0073] A dutch 211 according to a second embodiment of the invention is illustrated in figures 9 to 11. For convenience features of the clutch 211 that are similar or correspond to features of the clutch 11 of the first embodiment have been referenced with the same reference numerals.

[0074] In this embodiment the input member 31 differs from that of the first embodiment in that it comprises ten recesses 235 rather than four. These recesses 235 are spaced equidistance around the periphery of the input member 29. An opening of each recess 235 opens inwardly away from the periphery of the input member 31 and has a dosed end with an apex 269. Each pawl 235 has an end 239 which is complementary in shape to the recess 235 such that there is positive engagement of the pawl end 239 and recess 235 so that the likelihood of the pawl 37 unintentionally disengaging the input member 29, or slipping from one recess 235 to an adjacent recess 235 is minimised. As would be apparent to a person skilled in the art, the clutch may incorporate any number of recesses.

[0075] The configuration of the clutch 211 of the second embodiment allows for a more accurate and faster clutch response due to the increase in the number of recesses 235.

[0076] A clutch 311 according to a third embodiment of the invention is illustrated in figure 12. For convenience features of the clutch 311 that are similar or correspond to features of the clutch 11 of the first embodiment have been referenced with the same reference numerals.

[0077] In this embodiment the activation means is mechanically activated. The output member 29 and a governor member 343 are biased by a biasing means, in the form of a spring 263 extending between a spring post 265 on the governor member 343 and a spring post 265 on the output member 29. Until the force of the spring 363 is overcome the governor member 343 remains in its first angular position and the pawls 37 are held in their retracted position, the clutch is disengaged. [0078] The activation means also comprises a plurality of masses 367 secured to the input member 31 At a predetermined speed the centripetal force generated by the masses counteracts the force of the spring to cause the governor member 343 to move to the second angular position causing the pawls to move to the extended position, whereupon engagement of each pawl with its respective recess in the input member fixes the input member relative to the output member, the clutch is now engaged.

[0079] The clutch of the present invention allows for very rapid response and can be manually or automatically activated between engaged and disengaged conditions. This enables the clutch to be utilised in a wide and varied array of applications, everything from electric and non-electric bikes to transmission systems of vehicles.

[0080] Modifications and variations such as would be apparent to the skilled addressee are considered to fail within the scope of the present invention.

The present invention is not to be limited in scope by any of the specific embodiments described herein. These embodiments are intended for the purpose of exemplification only. Functionally equivalent products,

formulations and methods are clearly within the scope of the invention as described herein.

[0081 ] Reference to positional descriptions, such as lower and upper, are to be taken in context of the embodiments depicted in the figures, and are not to be taken as limiting the invention to the literal interpretation of the term but rather as would be understood by the skilled addressee.

[0082] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms“a”,“an” and“the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprise”,“comprises,”“comprising,”“including,” and“having,” or variations thereof are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. [0083] When an element or layer is referred to as being“on”,“engaged to”, “connected to” or“coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on," “directly engaged to”, “directly connected to" or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g. , “between” versus“directly between,"“adjacent” versus“directly adjacent,” etc.). As used herein, the term“and/or” includes any and all combinations of one or more of the associated listed items

[0084] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as“first,"“second," and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0085] Spatially relative terms, such as“inner,” “outer,” “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feafure(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as“below” or “beneath” other elements or features would then be oriented“above” the other elements or features. Thus, the example term“below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Claims

1. A dutch which is moveable between an engaged condition and a disengaged condition, the clutch comprising an output member which is selectively connected to an input member, wherein the axial distance between the output member and the input member is fixed; an engagement means which is adapted to move from a first position to a second position; and an activation means; wherein when the engagement means is in the first position the clutch is in the disengaged condition, whereupon activation of the activation means the engagement means moves to the second position to fix the output member relative to the input member such that the clutch is in the engaged condition.

2. The clutch according to claim 1 wherein the output member and the input member are fixed relative to each other when selectively connected, and rotate freely with respect to each other when not connected.

3. The clutch according to claim 1 wherein the output member and input member are coaxially mounted, the output member and input member rotating independent of each other when the clutch is in the disengaged condition, and are rotatably fixed relative to each other when the clutch is in the engaged condition.

4. The clutch according to claim 1 , 2 or 3 wherein the output member and input member are coaxially mounted on an output shaft, the output member being fixed to the output shaft.

5. The clutch according to claim 4 wherein the input member comprise a bearing, the input shaft being adapted to be mounted on the output shaft.

6. The dutch according to any one of claims 1 to 5 wherein the input member is adapted to be connected directly or indirectly to an input shaft.

7. The clutch according to any one of claims 1 to 6 wherein the engagement means comprises at least one engaging portion which selectively fixes the output member relative to the input member.

8. The clutch according to claim 7 wherein the at least one engaging portion engages with the output member to fix the output member relative to the input member

9. The dutch according to claim 7 wherein the at least one engaging portion engages with the input member to fix the output member relative to the input member.

10. The clutch according to any one of claims 7 to 9 wherein the at least one engaging portion is movable between a retracted position wherein the output member and input member are independent of each other, and an extended position wherein the output member and input member are fixed relative to each other.

11. The clutch according to claim 10 wherein the at least one engaging portion is biased to a retracted position.

12. The clutch according to any one of claims 7 to 11 wherein the input member comprises a receiving portion for receiving the engaging portion.

13. The clutch according to any one of claims 7 to 12 wherein each of the at least one engaging portions is in the form of a projection which moves between the retracted position and the extended position.

14. The clutch according to any one of claims 7 to 12 wherein each of the at least one engaging portions is in the form of a pawl pivotally mounted on the output member such that the pawl pivots between the retracted position and the extended position.

15. The dutch according to claim 14 wherein the receiving portion of the input member is in the form of a recess, the recess being adapted to receive an end of the pawl as the pawl moves to the extended position, each recess being configured to retain the pawl therein to fix the output member to the input member. .

16. The dutch according to claim 14 or 15 wherein there are at least two pawls spaced angularly equidistant from each other, the input member having at least two recesses spaced equidistant from each other.

17. The clutch according to claim 14, 15 or 16 wherein the recess releases the pawl when the rotational speed of the input member is greater than the rotational speed of the output member, allowing the output member and input member to rotate independently of each other. .

18. The dutch according to any one of claims 14 to 18 wherein each pawl is biased to the retracted position when released from the recess.

19. The clutch according to any one of claims 1 to 18 wherein the activation means comprises a governor member which is operably connected to the engagement means to move the engagement means between the retracted position and the extended position.

20. The clutch according to claim 19 wherein the governor member is coaxially mounted with the output member and input member, and is pivotally connected to each pawl.

21. The clutch according to claim 19 or 20 wherein the governor member is mounted to the output member such that it is movable between a first angular position, wherein each pawl is in the retracted position, and a second angular position, wherein each pawl is in the extended position.

22. The clutch according to claim 19, 20 or 21 wherein each pawl has an arm extending therefrom, wherein an end of that arm is secured to the governor member,

23. The clutch according to claim 22 wherein each arm is retained relative to a slot formed in the governor member.

24. The clutch according to any one of claims 19 to 23 wherein the activation means is electronically activated, and acts in a radial orientation relative to the clutch.

25. The clutch according to claim 24 wherein the activation means comprises a rotary voice coil which, upon activation, causes the governor member to move from the first angular position to the second angular position.

26. The clutch according to any one of claims 19 to 23 wherein the activation means is mechanically activated.

27. The clutch according to claim 26 wherein the output member and the governor member are biased by a biasing means, whereby the governor member remains in its first angular position and the pawls are held in the retracted position until the force of the biasing means is overcome.

28. The clutch according to any one of claims 1 to 27 wherein the activation means is caused to activate by a control means.

29. The clutch according to claim 28 wherein the control means incorporates a plurality of sensors which monitor one or more characteristics associated with the clutch, these characteristics including one or more of the following: linear velocity of the clutch, angular position of the clutch, angular velocity of the output member, angular velocity of the input member.

30. The clutch according to claim 29 wherein the control means causes activation of the activation means when the one or more characteristics being monitored reach predetermined values.

31. The clutch according to claim 28 wherein the control means comprises a switch which is manually operable to activate the activation means.

32. A dutch which is moveable between an engaged condition and a disengaged condition, the dutch comprising an output member which is selectively connected to an input member, wherein the axial distance between the output member and the input member is fixed; an engagement means which is adapted to move from a first position to a second position to fix the output member to the input member; and an activation means; wherein the clutch is in the disengaged condition when the engagement means is in the first position, whereupon activation of the activation means the engagement means moves to the second position to fix the output member relative to the input member whereby the clutch is in an engaged position.

33. A clutch which is of fixed width and is moveable between an engaged condition and a disengaged condition, the clutch comprising an output member; an input member which is selectively fixed to the output member; an engagement means which is adapted to move from a first position to a second position to fix the output member to the input member; and an activation means; wherein the clutch is in the disengaged condition when the engagement means is in the first position, whereupon activation of the activation means the engagement means moves to the second position to fix the output member relative to the input member whereby the clutch Is in an engaged position.

34. A clutch comprising: a first member adapted to be fixed relative to an input; a second member adapted to be selectively fixed to the first member, the second member providing an output; an engagement means to engage the first member relative to the second member; an activation means to activate the engagement means between an engaged position, wherein the clutch is in an engaged condition and a disengaged position wherein the clutch is in a disengaged condition; whereupon activation of the engagement means the clutch is in the engaged condition such that the first member is fixed to the second member to transfer the input to the output, whereupon the engagement means moving to the first condition the clutch is in the disengaged condition such that the first member is independent of the second member, the width of the clutch remaining constant as it moves between its engaged condition and disengaged condition.

35. A clutch comprising: an output member which is selectively connected to an input member, the axial distance between the output member and the input member being fixed; an engagement means which is adapted to move from a first position to a second position; and an activation means; wherein when the engagement means is in the first position the clutch is in a disengaged condition, whereupon activation of the activation means the engagement means moves to the second position to rotationaily fix the output member to the input member such that the dutch is in an engaged condition.

36. A transmission system comprising one or more dutches according to any one of the preceding claims.

37. A bicycle transmission system comprising one or more dutches according to any one of claims 1 to 35, wherein the output member is mounted on a crank shaft which supports crank arms, and the input member is connected to a rear sprocket of a rear wheel of the bicycle by a chain which passes through a series of gears.

38. A clutch which is moveable between an engaged condition and a disengaged condition, the clutch comprising an output member which is selectively connected to an input member; an engagement means which is adapted to move from a first position to a second position to fix the output member to the input member; and an activation means; wherein the clutch is in the disengaged condition when the engagement means is in the first position, whereupon activation of the activation means the engagement means moves to the second position to fix the output member relative to the input member whereby the clutch is in an engaged position.