Abstract: A derailleur cable router changes the direction of a derailleur cable operatively attached to a rear derailleur to a bicycle frame. The rear derailleur is actuated by variation in tension applied to the derailleur cable from a direction rearward of the derailleur. The tension in the derailleur cable is controlled by a shifter attached to a distal end of the derailleur cable, the shifter being mounted to the bicycle frame forward of the derailleur. The derailleur cable includes a cable housing around at least a portion of the derailleur cable with the derailleur housing being fixed against lengthwise movement relative to the bicycle frame by attachment to the bicycle frame. The derailleur cable router includes a frame having a first and a second end. A housing is provided at the first end of the frame and the housing is attachable to a derailleur cable housing. A second housing is provided at the second end of the frame, the second housing being attachable to a derailleur cable feed of a rear derailleur.

Abstract: A bicycle derailleur gear shifting system having a rotatable handgrip actuator coupled with a derailleur shifting mechanism through a control cable system so as to control the derailleur. The derailleur (50) includes an arcuate cable entraining surface (78) which substantially reduces the variation and magnitude of the actuation ratio between control cable linear displacement and movement of the derailleur p-knuckle (88). A b-knuckle flange (160) militates against the derailment of the drive chain from the upper guide wheel while permitting maximum lateral flexing of the drive chain (48) during shifting between sprockets (46) on the freewheel. A rigid arcuate surface (174) may be provided as an extension of the b-knuckle (170) in replacement of a segment of a Bowden cable housing (38) to obviate the accumulation of water and foreign matter.

Abstract: A shift control device includes a movable member having a cable support for supporting the transmission cable, wherein the movable member moves as the shifting device actuates the transmission. An assist spring is provided for biasing the movable member in a direction opposite a direction of biasing of the movable member by the return spring of the transmission. The cable support supports the transmission cable such that tension exerted by the assist spring on the transmission cable remains substantially constant regardless of a position of the movable member as the shifting device actuates the transmission. In a more specific embodiment, the cable support moves the transmission cable in a straight line, and the cable support may move the transmission cable without winding the transmission cable about the cable support.

Abstract: A linear derailleur for positioning a drive chain in response to displacement of a control cable. The derailleur includes a linear actuator having a substantially uniform actuation ratio over the range of motion of the actuator and, hence, derailleur. The linear actuator also has a mean actuation ratio over its range of motion equal to Cos .theta.:1, where .theta. equals the angle of inclination of the actuator.

Abstract: The derailleur cable-collet system is an automatic pedal-rate to wheel-rate adjusting system. Pedal pressure is sensed at the crankshaft hub and electronically compared to pedal-pressure threshold values entered by the rider into an electronic circuit. Pedal velocity is sensed at the front sprocket and electronically compared to velocity threshold values. Shifting decision logic is relayed to feed battery current into solenoid-driven collets that move derailleur cables. An arc-jaw collet moves derailleur cable in one direction, and employs spring-forms for structure and bias. A distribution circuit senses travel limits of derailleur arms and redirects cable travel to another derailleur chain-guiding apparatus. A pedal-position sensor contributes to a pedal shifting time circuit that minimizes chain force during sprocket-shifting actions.

Abstract: An electro-mechanical system for shifting gears on a multi-gear bicycle or other human-powered vehicle includes a closed loop derailleur position control system using circuitry for measuring derailleur position. Shifting gears is accomplished automatically based on rider cadence or manually using signals supplied by hand operated switches. The system calculates gear ratios based on bicycle speed and cadence and then sorts the gear ratios in order from lowest to highest. During automatic operation, the system calculates a cadence from bicycle speed and gear ratio, determines if the calculated cadence is within predetermined limits set by the rider, and it changes the gear ratio if the calculated cadence is not within the predetermined limits.

Abstract: A rear derailleur (50) is provided with an arcuate cable entraining surface (78) which substantially reduces the variation and magnitude of the actuation ratio between control cable linear displacement and movement of the derailleur p-knuckle (88). A b-knuckle flange (160) militates against the derailment of the drive chain from the upper guide wheel while permitting maximum lateral flexing of the drive chain (48) during shifting between sprockets (46) on the freewheel. A rigid arcuate surface (174) may be provided as an extension of the b-knuckle (170) in replacement of a segment of a Bowden cable housing (38) to obviate the accumulation of water and foreign matter.

Abstract: A bicycle derailleur control apparatus includes at least one input device for setting a derailleur position of at least one derailleur, at least a transmission device connected to the derailleur via a cable, a control device electrically connected to the at least one input device and the at least one transmission device for activating the transmission device to pull or release the cable to a level in response to the setting from the input device thus changing the derailleur position.

Abstract: An improved form of bicycle speed change mechanism, characterized in that, a speed change support is installed to sustain and keep a bicycle chain at a fixed tension; a stop ring installed on the speed change support is bent to one side to form a positioning plate that is bent outwardly; a C-type snap ring is inserted in the gap of a support shaft; one end of the C-type snap ring extends outwardly to form a handle; one end of the handle forms a horizontal plate on which two guide holes are formed; two bolts are mounted in the guide holes; adjustment of the length of the two bolts extruding from the guide holes of the horizontal plate controls the angle of rotation of the stop ring wtih respect to the baffle angle of the bicycle frame, and consequently changes the force produced by the torsion spring which is dragged by the stop ring.

Abstract: A front derailleur for a bicycle has a four-point link mechanism, and a control cable is attached by a screw to an end of a connecting arm fixed to one link of the four-point link mechanism. The connecting arm has an auxiliary projection. The control cable applies a torque to the link at a point of contact between the control cable and the auxiliary projection. The screw on the connecting arm is spaced from a chain guide which contacts a chain, to facilitate an operation to attach the control cable to the connecting arm.

Abstract: A bicycle frame supports a sprocket, front and rear wheels and first gears axially aligned with the rear wheel. Each gear has an individual ratio with the sprocket. At a first end, a support is attached to the frame at two (2) spaced positions, one axially aligned with the rear wheel. When loosened from the frame at such aligned position, the support is pivotable at the other position to provide access to the rear wheel and the gears for maintenance or repair. At its second end, the support holds a hollow shaft in a direction substantially parallel to the gear peripheries. A drive motor, a screw and a yoke mounted on the screw extend in this parallel direction within the shaft. Channels in the shaft receive the yoke to constrain yoke rotation. The motor drives the screw and yoke to position a spool linearly in the parallel direction. A takeup arm movable with the spool carries an additional gear into alignment with an individual one of the gears.

Abstract: A powered control device for speed change in a bicycle comprises an electric motor directly mounted onto the rear derailleur and is provided with an encoder for detecting the position of the rear derailleur.

Abstract: The jockey wheel, intended to be incorporated in the derailleur of a bicycle, permits limited lateral sliding movement of its outer ring gear relative to a central bushing, but requires a rolling bearing between the outer ring gear and the central bushing to rotate by fixing the ring gear to the outer race of the rolling bearing and the bushing to the inner race of the rolling bearing. In one construction, bushings between the inner race and shaft carrying the jockey wheel are keyed to one another to permit only lateral sliding movement. In another construction, the inner race of the rolling bearing is eccentrically shaped to interfit with the bushing, thereby permitting only lateral sliding movement between the eccentrically shaped inner race and bearing but requiring the inner race to rotate with the bushing.

Abstract: A rear derailleur bracket for connecting a rear derailleur to a bicycle frame, utilizing a coupling device formed on a derailleur mounting extension of a rear fork end of the bicycle frame. The rear derailleur bracket includes a bracket body, a first bolt bore provided adjacent one end of the bracket body for connecting the rear derailleur to the bracket body, a second bolt bore provided adjacent the other end of the bracket body for connecting the bracket body to the coupling device of the bicycle frame, and a projection acting as a position setting device for contacting the derailleur mounting extension to place the rear derailleur in a predetermined posture relative to the rear fork end. The projection extends substantially vertically from a surface of the bracket body.

Abstract: A pedal-force chain-shifting apparatus senses a rider's peak force within each half revolution of a pedal set. A shift-down pedal pressure is set to match a rider's weight, strength and stamina objectives. A displacement mechanism compares the peak force with the pressure setting, and uses a portion of chain energy to actuate derailleur chain-shifting mechanisms to guide chain onto larger rear wheel sprocket size. A digital force-averaging mechanism measures a series of less than full pressure cycles to sense a cycle in which a portion of chain energy pulses the derailleur to shift-up by guiding the chain onto a smaller sprocket. This apparatus replaces need for a bicycle rider to anticipate and select appropriate sprockets at front and rear derailleur apparatus.

Abstract: The following technical measure is taken to provide a bicycle speed change system or method wherein a speed change operation can be performed substantially without unhanding a handlebar and without erroneously shifting to a lower or higher speed.Specifically, the bicycle speed change system (1) comprises a front speed shifter (1a), a rear speed shifter (1b), and speed change operation assemblies respectively including cylindrical operation members (4a, 4b) rotatably supported around right and left grip portions (3a, 3b), respectively, of a handlebar (2); each of the shifters being operated by a control cable (T) which is pulled or released by rotating a corresponding one of the cylindrical operation members, wherein each of the cylindrical operation members (4a, 4b) is designed so that rotation thereof in a direction of moving its top surface rearward causes a corresponding one of the shifters (1a, 1b) to shift to a lower speed position.

Abstract: A bicycle front derailleur includes a support ring secured to the seat tube of the bicycle frame. The support ring has a side extension on which two links are pivoted. The two links are further pivoted to a chain mover member through which the drive chain extends to be moved thereby. The two links, the side extension and the chain mover member form a parallelogram linkage. One of the links has a sideways lever attached thereto with a control cable secured to the lever so that by pulling the control cable with a manual shifter, the lever rotates the link about the pivot thereof with the side extension so as to move the chain mover member with the coupling of the other pivot thereof to the chain mover member. A biasing spring is disposed between the support ring and the link having the lever thereon to bias the link to an originally-set position.

Abstract: There is provided a bicycle rear derailleur wherein a problem that shifting the chain to a diametrically larger sprocket causes the guide pulley to come too close to the sprocket, which is an inherent problem to a conventional bicycle rear derailleur using a double tension mechanism, is rationally solved with further improved speed change efficiency. This rear derailleur comprises a rearwardly extending control mechanism (23) pivotally supported at a front end portion thereof to a bicycle frame (22) ahead of the multiple sprocket assembly, the control mechanism mounted at a rear end portion thereof with a chain guide (25) rotatably supporting a guide pulley (39) and a tension pulley (40), wherein the control mechanism is urged against the bicycle frame in a clockwise direction about a first lateral shaft (34), and the chain guide is urged against a chain guide mount of the control mechanism in a clockwise direction about a second lateral shaft (41).

Abstract: A handlebar mounted brake control mechanism for a Bowden brake cable or the like includes a handlebar having at least one end, a tubular handle member having first and second ends configured to telescopically slide over one end of the handlebar and being coaxially rotatable thereabout between a relaxed position and a braking position. A handle member biasing mechanism is located on the handlebar for biasing the handle member into the relaxed position, and a handle member guide is used to axially displace the handle member reciprocally between the relaxed position and the braking position. The handle member biasing mechanism is configured such that when the overriding force applied by the user to rotate the handle member into the braking position is released, the handle member biasing mechanism returns the handle member to the relaxed position from the braking position. Additionally, the handle member has an attachment for releasably accommodating an end of the brake cable.

Abstract: Gear shifting device for a cycle having a chain and pinion transmission is provided, which includes a mobile gear shift assembly adapted to laterally displace the chain for enabling passage from one gear to another gear; transformation elements for transforming rotation of at least one pivoting gear into a lateral displacement of the mobile gear shift assembly; and a control mechanism for controlling lateral displacement of the mobile gear shift assembly. Further, the gear shifting device can include an indexing mechanism to further ensure exact positioning of the gears.

Abstract: An electro-mechanical system for shifting gears on a multi-gear bicycle or other human-powered vehicle includes a closed loop derailleur position control system using circuitry for measuring derailleur position. Shifting gears is accomplished automatically based on rider cadence or manually using signals supplied by hand operated switches. The system calculates gear ratios based on bicycle speed and cadence and then sorts the gear ratios in order from lowest to highest. During automatic operation, the system calculates a cadence from bicycle speed and gear ratio, determines if the calculated cadence is within predetermined limits set by the rider, and it changes the gear ratio if the calculated cadence is not within the predetermined limits.

Abstract: An electrical adjustment device, in particular an electrical chain transfer device for bicycles is disclosed, comprising an adjusting element, a drive device for the adjusting element, a control unit for controlling the drive device and a presetting device connected with the control unit for presetting a plurality of set values, where each of these set values corresponds to an operational position of the adjusting element. In the adjustment device of the invention the adjusting element can be moved into respectively one set position corresponding to a desired operational position for fixing or, if required, correcting of the set values, and the resulting instantaneous value can be stored in the presetting device as the new set value.

Abstract: An electromechanical bicycle transmission (10) comprises an electric motor (16) controlling through a first rigid mechanism (29) the movement of a first element (28) connected through preloaded yielding springs (24,25) to a second movement element (21) through another rigid mechanism (18,19,20) of a sprocket change mechanism member (11) moving to engage a transmission chain (12) opposite a predetermined sprocket of a plurality of coaxial sprockets (13) of different diameters.

Abstract: The present invention provides a bicycle front derailleur comprising: a movable member including an inner and outer guide plates opposed to each other to define a guide space through which a chain runs; the movable member being moved laterally of a bicycle for shifting the chain. For a purpose of preventing the chain from being caught or damaged by a chain entering edge of the movable member, a following techincal measure is employed: The movable member is provided with catch preventive measure for preventing the chain from being caught by the cain entering edge of the movable member when the chain enters the guide space between the inner and outer guide plates.

Abstract: A derailer for derailing a drive chain from one sprocket to an adjacent sprocket of a multi-stage sprocket assembly wherein operation of the derailer thereof is automatically controlled by centrifugal force so that the driving chain is automatically shifted to higher gears as the speed of the bicycle increases.

Abstract: A bicycle has front and rear wheels, a sprocket coupled to a pedal crank, a sprocket gear, gears on the rear wheel and a gear chain extending around the sprocket gear and an individual one of the rear wheel gears. The chain is adjustably coupled to the individual gears on the rear wheel to respectively increase and decrease the gear ratio relative to the sprocket gear for sprocket speeds above the upper limit and below the lower limit. The upper limit is adjustable as by initially operating up and down switches together within a particular time limit and then operating the up switch for upper limit increments or the down switch for upper limit decrements. The sequence may then be repeated for lower limit adjustments. The movement of a particular number of sprocket ribs past a detector and the time for such movement are measured and processed to determine the sprocket speed. When the sprocket is rotating continuously at a speed below the lower limit, as when coasting downhill, the gear ratio is not changed.

Abstract: A bicycle front derailleur has a guide assembly for shifting a chain among a plurality of sprockets of different sizes. The guide assembly comprises an outer guide plate, an inner guide plate extending substantially parallel to the outer guide plate, and bridge members interconnecting the outer and inner guide plates in a spaced relationship. The inner guide plate includes an upper plate portion, and a lower plate portion extending from the upper plate portion. The lower plate portion includes a first plate portion and a second plate portion, the second plate portion being elastically deformable relative to the first plate portion axially of the sprockets.

Abstract: An anti-chain wrap device for bicycles has a short mounting plate with large fastener holes for universal adjustments in the plane thereof and a clamp plate fastener with conventional fastener holes. Chain lifter fingers for contacting chain stuck on a chainring have portions bent out of the plane thereof to avoid interference on chainrings having extra teeth thereon. The fastener plate may have a fender mounting tab thereon as well as a control cable guide.

Abstract: A roller intake mechanism having an operating force amplifying device includes a cam (7) rotatable about an axis of an axle a plurality of rollers (8) displaceable with rotation of the cam, a roller case (9) for displaceably retaining the rollers, a brake drum (5) extending from a wheel hub (2), and a brake shoe (10) disposed between the rollers and brake drum for contacting the brake drum with displacement of the rollers. The amplifying device is formed as a clamping ring (18) having one end thereof operatively connected to a brake lever (100) through an interlocking wire (150), and the other end operatively connected to the cam. An intermediate portion of the ring is wound around a peripheral surface of the brake drum. Based on a primary operating force applied from the brake lever, the clamping ring clamps the brake drum, which produces a frictional force for allowing the clamping ring to take power from the brake drum, i.e. the wheel hub.

Abstract: A bicycle gear shifting system having rotatable front and rear handgrip shift actuators operatively associated with control cables for shifting respective front and rear derailleur mechanisms. In some forms of the invention the control cable is directly actuated by the handgrip rotator, while in other forms the shifter rotator drives a separate "jack spool" which in turn actuates the control cable. A cam on either the handgrip rotator or the jack spool is configured so as to substantially compensate for increasing force of the derailleur return spring during down-shifting. Compensation is provided in the shift actuators of the invention for various lost motions in the derailleur shifting mechanisms and control cable systems.

Abstract: In a chain thrower mechanism of a bicycle derailleur gear mechanism a parallelogram is formed by at least four parts. One of these parts is prefabricated by injection moulding with respective hinge portions. A second of these parts is formed with respective hinge portions by using one hinge portion of the prefabricated part as a shape-giving part for injection moulding of the other part.

Abstract: In a chain thrower mechanism of a bicycle derailleur gear mechanism a parallelogram linkage is formed from plastics material at least part of the joints of which are plastic film hinges.

Abstract: A derailer for derailing a drive chain from one sprocket to an adjacent sprocket of a multi-stage sprocket assembly wherein operation of the derailer thereof is automatically controlled by centrifugal force so that the driving chain is automatically shifted to higher gears as the speed of the bicycle increases.

Abstract: A bicycle transmission comprises a sprocket assembly rotatably coupled to the frame of a bicycle for receiving a chain, a front and rear sprocket selector for causing the sprocket assembly to shift the chain from one sprocket to another, a sliding bracket for retractably mounting the sprocket selector to the bicycle frame, adjustment brackets for finely adjusting the front and rear sprocket selectors to correspond to the path of the sprocket assembly, and a compensator for engaging and following the chain as it is shifted between sprockets to eliminate any free chain between the compensator and the sprocket and for reentraining the chain in the event of complete derailment. In addition, the bicycle transmission may include a sprocket assembly comprising a stationary sector, a swinging sector hingedly coupled to the stationary sector, and a plurality of load bearing surfaces extending radially outwardly of the stationary sector for taking the load from the swinging sector.

Abstract: A low effort shifter for multispeed bicycles and the like having cable operated derailleurs is provided, comprising a circular spool rotatably mounted in a housing. The derailleur control cable is operatively anchored to the spool so that when the spool is rotated, the derailleur changes position. A force cancellation spring is anchored to the spool so as to counteract and oppose the moment imposed upon the spool by the derailleur bias spring. The force cancellation spring is routed in a circular path around said spool and extends to a linear path into a straight portion of the housing, where the spring is coupled to a preload adjustment screw. The spool has a gear thereon which is engaged with a second gear, the second gean being coupled to a shift knob outside the housing. The shift knob may be selectively operated by the rider using substantially negligible force to effectuate drive ratio changes.

Abstract: A bicycle derailleur gear shifting system having a rotatable handgrip actuator cam which is coupled with the derailleur shifting mechanism through a control cable system so as to control the derailleur mechanism. Separate actuator cams are associated with the front and rear derailleurs. For the down-shifting direction, at least the rear derailleur cam is configured so as to substantially compensate for increasing force of the derailleur return spring; so as to substantially compensate for numerous cumulative lost motions in the derailleur shifting mechanism and cable system; and so as to overshift the chain a sufficient amount beyond the destination freewheel sprocket so that the chain will approach the destination sprocket in the same direction as it would in the up-shift direction, but not sufficient to cause a double shift, or derailling from the #1 sprocket. A front derailleur cam is configured to provide fine-tuning for "cross-over" riding.

Abstract: A freewheel for bicycles has a plurality of gears each of which, with the exception of the one with the smallest diameter, has teeth arranged in successive sets of three constituted each by teeth of three different types. A first type of tooth has a face which is recessed relative to the corresponding flat face of the gear. A second type of tooth has a groove formed in the top surface of the tooth and extending circumferentially of the gear. A third type of tooth has a top chamfer on its face situated on the side opposite the recessed face of the first tooth.

Abstract: An electro-mechanical system for shifting gears on a multi-gear bicycle or other human-powered vehicle includes a closed loop derailleur position control system using a circuitry for measuring derailleur position. Shifting gears is accomplished automatically based on rider cadence or manually using signals supplied by hand operated switches. The system calculates gear ratios based on bicycle speed and cadence and then sorts the gear ratio in order from lowest to highest. During automatic operation, the system calculates a cadence from bicycle speed and gear ratio, determines if the calculated cadence is within predetermined limits set by the rider, and it changes the gear ratio if the calculated cadence is not within the predetermined limits.

Abstract: An automatic derailleur shifter system for example for a bicycle includes a hub to which is attached a chain wheel set and a derailleur system for moving the chain associated therewith from chain wheel to chain wheel for a gear changing system. Within the hub associated with the chain wheels is provided an automatic changing system including a member coupled to the chain wheel set which carries a helical screw cooperating with a sleeve slidable axially within the hub and cooperating with the screw so that rotation of the screw relative to the sleeve causes the sleeve to move axially. Axial movement of the sleeve is inhibited by a spring and rotational movement of the sleeve is prevented by engagement with the hub. Thus variations in the torque applied from the chain set to the hub through the screw in the sleeve cause axial movement of the sleeve which actuates change of the gears by moving to the derailleur set. The spring can be internal to the hub or can be provided outside of the hub.

Abstract: Chain control apparatus is provided for a bicycle having a chain journaled around spaced apart gears so as to have an upper run and a lower run wherein the chain control apparatus limits movement of the lower run in directions away from the upper run when the bicycle is operated in rough terrain or is used in jumping operations and wherein the chain control apparatus is mounted for permitting pivotal movement thereof around a generally horizontal axis and around at least one generally vertical axis.

Abstract: A shift lever assembly for use in a bicycle wherein a wire connected at its one end to a derailleur is wound up or paid out to operate the derailleur. The assembly comprises a lever pivot fixed to the handlebar of the bicycle; a shift lever having a base-end boss portion rotatably supported by one end of the pivot and an arm portion extending from the boss portion; wire winder separate from the lever and rotatably supported by the pivot; a lever-coupled member provided between the boss portion and the winder and supported by the pivot so as to be rotatable with the winder; and a clutch for transmitting the rotation of the shift lever to the lever-coupled member. The shift lever is so biased by a spring as to return to a neutral position for starting rotation toward the wire winding direction and the wire paying-out direction.

Abstract: A dual driven cycle and a kit for converting conventional, single driven cycles into dual driven cycles are disclosed. The invention is suitable for accommodating bicycles, motorcyles, dirt bikes, and other conventional cycles. These cycles have the known elements of a pedal-gear-chain driven first wheel and a non-driven second wheel. The kit comprises four general elements. First, a sprocket is connectable in fixed relation to the non-driven second wheel for conjoint movement with that wheel. Second, to receive power from the conventional drive train, a drive gear is mounted on either the pedal gear or chain of the cycle. Third, a cable gear is provided for mounting with respect to the cycle's frame and meshing with the sprocket. This cable gear drives the sprocket and, of necessity, the cycle's previously non-driven second wheel. The final general element of the kit is a rotatable cable which connects the cable gear to the drive gear and transfers the rotational motion of the drive gear to the second wheel.

Abstract: The invention relates to the engineering sector of cycle accessories.The derailleur in accordance with this invention is worthy of note as the rear part of the forks (1) (2) is formed to take a quick fixing system to provide for bracing them.

Abstract: An anti-chain wrap device has a plurality of lifters which are raised and curved to be adjacent the rotary path of the chainrings, respectively, to strip or free a struck chain from the chainring. The lifters are finger blade members which are joined near their lower ends to provide a more rigid construction.

Abstract: A front derailleur for use in a bicycle. The front derailleur provides a plurality of speeds through selective engagement of a driving chain with any one of at least three sprockets by applying a control force to a portion of a link mechanism urged by an urging member thereby moving a chain guide connected with the link mechanism against the urging force of the urging member. The link mechanism is operable to move the chain guide while varying its posture so as to provide an increased pivot amount between the sprocket pair adjacent the urging side whereas to provide a reduced pivot amount between the sprocket pair distant from the urging side, in comparison with the conventional mechanism of this type. This novel construction permits sufficient urging force at the middle sprocket position in accordance with increase in the deformation amount of the urging member, thereby to provide a reliable change speed operation by the sufficient urging force.

Abstract: A rotatable sprocket assembly transmits force from a chain into rotation of a wheel on a bicycle. A plurality of sprocket segments having peripheral teeth are mounted on a pair of sprocket housings so that the combined periphery of the sprocket segments is substantially circular. The sprocket segments are slidable relative to the housing in a substantially radial direction so as to vary the diameter of the combined sprocket segments. Each sprocket segment is formed from a plurality of hinged subsegments, with each subsegment having a single tooth thereon. The sprocket segments of one housing overlap the adjacent sprocket segments on the other housing so that the pairs of overlapping teeth combine to effectively form a single tooth. The sprocket segments are movable angularly relative to the sprocket housings, so that in combination with the radial displacement of the sprocket segments, the total number of effective teeth on the sprocket assembly can be varied in increments of one tooth.

Abstract: A bicycle gear shift mechanism (8) to be actuated by an electric motor (m) has a carrier for an actuator member (S) comprising a tensioning arm (29) of a derailleur or a shift plunger of a hub gear transmission. According to the invention, the carrier comprises a cursor (27) slidably displaceable on at least two spaced parallel guides (26) mounted at stationary positions with respect to a housing (18). According to a further aspect, a control circuit for the bicycle gear shift mechanism to be actuated by a DC motor comprises a first and a second power control circuit (70,71) controlled by first and second flip-flop circuits (60, 61) the set inputs of which are connected to switches (68, 69) for shifting to higher or lower gear ratios, and the reset inputs of which are adapted to by activated via a switch (65) which is responsive to the gear-engaged state of the gear shift mechanism.

Abstract: An automatic derailleur shifter is disclosed which includes a hollow cylinder body and a piston rod movable within the cylinder. The piston rod carries a dual element piston within the cylinder body in a manner to permit substantially unrestricted fluid flow through the piston when the piston rod is moved in a first, upward direction and a greatly restricted fluid flow when the piston rod is moved in the second downward direction. A first, fixed piston element is fabricated of diameter less than the inner diameter of the cylinder to allow unrestricted fluid flow thereabout. A second, movable piston element is provided and below the fixed piston element includes a flared skirt for sliding, sealing engagement between the movable piston element and the cylinder. A small, restricted longitudinal channel is provided through the fixed piston element which terminates at its lower end at a circular channel.

Abstract: A bicycle derailleur gear shifting system having a rotatable handgrip actuator cam which is coupled with the derailleur shifting mechanism through a control cable system so as to control the derailleur mechanism. Separate actuator cams are associated with the front and rear derailleurs. For the down-shifting direction, at least the rear derailleur cam is configured so as to substantially compensate for increasing force of the derailleur return spring; so as to substantially compensate for numerous cumulative lost motions in the derailleur shifting mechanism and cable system, and for chain gap variations; and so as to overshift the chain a sufficient amount beyond the destination freewheel sprocket so that the chain will approach the destination sprocket in the same direction as it would in the up-shift direction, but not sufficient to cause a double shift, or derailling from the #1 sprocket. A front derailleur cam is configured to provide fine-tuning for "cross-over" riding.

Abstract: Chain control guide apparatus is provided for a bicycle having a chain journaled around spaced apart gears so as to have an upper run and a lower run wherein the chain control guide apparatus, such as an idler pulley, limits movement of the lower run in directions away from the upper run when the bicycle is operated in rough terrain or is used in jumping operations.