Abstract: A transmission including an input cog assembly mounted to an input shaft and an output cog assembly mounted to an output shaft. The input and output cog assemblies include a plurality of varying diameter input and output cogs, respectively, arranged sequentially. A chain links a pair of input and output cogs for transmitting power from the input cog assembly to the output cog assembly. The chain, in operation, has a high-tension side and a low-tension side. A derailleur is engageable with the low-tension side of the chain to laterally urge the chain from a current output cog to a destination output cog.

Abstract: A bicycle component is configured with an axle fixing structure. In the preferred embodiment, the bicycle component is an electric derailleur. The bicycle component has a base member rotatably supported on an axle. Preferably, the axle includes a shaft portion with a head portion disposed adjacent a first end of the shaft portion for limiting axial movement of the base member in a first axial direction of the shaft portion, and a threaded portion disposed adjacent a second end of the shaft portion with external threads. A first locking member is threaded onto the external threads and configured to limit axial movement of the base member in a second axial direction of the shaft portion. Preferably, a second locking member is threaded into the internal threads of the second end of the shaft portion to secure the first locking member on the fastening portion of the axle.

Abstract: A gearshift control device for a chain and sprocket transmission system including a gearshift member that is movable along a transverse direction relative to the plane defined by the chain, a shaft, a first driving element having a drive member that is non-centered or non-concentric with respect to the axis of the shaft, a second positioning element of the derailleur with an indexing device, a third control element mounted to rotate freely about the shaft with a blocking device, and a transmission element having a member for connection with the first driving element, the second positioning element and the third control element, the transmission element being operably between the first driving element, the second positioning element, and the third control element.

Abstract: A gear-shifting apparatus is provided which does not require a position of a chain to be set with high precision, and which reduces a risk of the chain coming off an adjacent sprocket due to a quick gear shifting operation. The gear shifting system includes a derailer for changing the chain from one sprocket to another among a plurality of axially-arranged gear shifting sprockets, and a case for containing the gear shifting sprockets and the chain. The case is provided with a protruding part for preventing the chain from moving axially outwardly at an area too close to the case. The protruding part effectively prevents the chain from coming off from the adjacent sprocket by means of contact of the protruding part with the chain.

Abstract: Gear assembly for a bicycle gear change, comprising at least one gear with a larger diameter and at least one gear with a smaller diameter. The selected gear, generally of a larger diameter, has at least one sector dedicated to upwards shifting that may include a plurality of shifting aid means to facilitate upwards shifting and a second gear, generally of a smaller diameter, has at least one sector dedicated to downwards shifting that may include a plurality of shifting aid means to facilitate downwards shifting.

Abstract: A bicycle front derailleur motor unit assembly is provided that includes a motorized front derailleur mounting member and a motor unit. The front derailleur mounting member is configured to be mounted to a bicycle frame. The front derailleur mounting member includes a front derailleur mounting portion configured to be coupled to a linkage of a front derailleur and a motor unit mounting portion. The motor unit includes a motor unit housing configured to be removably coupled to the motor unit mounting portion and an output shaft configured to rotate about a rotation axis relative to the motor unit housing in first and second opposite rotational directions. The motor unit mounting portion and the motor unit housing include first and second fastener-less mating structures configured to resist rotational movement of the motor unit housing relative to the front derailleur mounting member due to a torque produced by the output shaft.

Abstract: A transmission includes a ball spline mechanism having an outer member which can rotate integrally with an inner member by means of balls housed in guide grooves and which can move in the axial direction; and a derailer which shifts a chain wrapped around a first sprocket moving integrally with the outer member from one transmission sprocket to another among a plurality of operating sprockets. The inner member and the outer member include guide surfaces through which the outer member is guided to move in the axial direction through the balls. The outer member is provided with a dust cover for covering the guide surfaces, regardless of the axial position of the first sprocket.

Abstract: To change the transmission gear ratios of a bike and reduce its dimensions as much as possible. The derailleur, located between the two cog sets (2,3), is the latest, newest and a very important device. Both cog sets (2,3) have parallel and reversed rotating axles so that the big diameter cog (5), located on the primary cog set (2) corresponds to the small diameter cog (6), located on the secondary cog set (3). The primary cog set is assembled on the primary axle and is linked to the secondary cog set by a primary looping ring roller chain (8); the secondary cog set (3) supports the single external cog (15), linked to the rear wheel by the secondary chain (8). When the derailleur is externally activated, it shifts the primary chain (8) to the primary and the secondary cog sets (2,3), having different diameters, so as to change gear.

Abstract: A bicycle front derailleur includes a chain guide that is provided with a pushing element that is movable relative to the chain guide to assist in shifting a bicycle chain from a smaller front sprocket to an adjacent larger sprocket. The chain guide is part of a movable member that is movably coupled to a base member via a linkage assembly. The pushing element has a contact surface that preferably moves both laterally outwardly and longitudinally as the pushing element moves from a first position to a second position. Preferably, the pushing element is chain activated and arranged to move at least laterally outwardly by contacting a chain that is moving between inner and outer chain guide members of the movable member. Preferably, the pushing element is either a slidable member or a rotatable member.

Abstract: A transmission apparatus is capable of retaining an endless transmission chain on a rotatable member, even where a small inter-axis distance remains between two rotatable shafts to which each of two rotatable members is drivingly connected. The transmission includes a drive sprocket member for connecting to a main drive shaft. The transmission also includes a driven sprocket member, connected to the output shaft in parallel with the main drive shaft and including a plurality of transmission sprockets. The transmission further includes a chain interconnecting both sprocket members, and a transmission shift mechanism for positioning the chain among the transmission sprockets. The drive sprocket member is supported at the main drive shaft in the rotary center line direction, in such a way that the chain is applied to both sprocket members in parallel with a plane crossing at a right angle with the rotary center line of the main drive shaft.

Abstract: An electronically servo-assisted gearshift actuates a multiple gear-shifting that moves a chain from a current toothed wheel to a target toothed wheel not immediately adjacent to the current toothed wheel in a gearshift group having at least three toothed wheels. Actuating the multiple gear-shifting takes several steps (i) actuating a single gear-shifting to move the chain to a toothed wheel immediately adjacent to the current toothed wheel in the gear-shifting direction, and (ii) repeating step (i) until the immediately adjacent toothed wheel is the target toothed wheel.

Abstract: A transmission apparatus for a bicycle is capable of performing a transmission operation even while operating or running by the inertia of the bicycle. The transmission apparatus T for a bicycle includes a driving sprocket member rotationally driven by a crankshaft; a multi-stage driven sprocket member drivingly connected to the output shaft cooperatively engaged and rotated with the rear wheel; a chain applied over the driving sprocket member and the driven sprocket member; and a transmission changing-over mechanism M2 for positioning the chain among a plurality of transmission sprockets. The driven sprocket member is integrally arranged to always be rotated, and the one-way clutch for transmitting a rotation of the crankshaft to the driving sprocket member while in its normal rotating direction is arranged in the power transmitting path extending from the crankshaft to the driving sprocket member.

Abstract: A bicycle transmission is configured and arranged to improve the durability of the transmission. The transmission basically has a transmission operating device, a support structure, a front input section, an intermediate transmission and a rear output section. The transmission operating device operates the intermediate transmission to change the gear ratio between the front input section and the rear output section. The intermediate transmission has a plurality of drive members arranged to move in the axial direction on an intermediate drive axle in response to its pivotal movement shifting structure. An endless drive member is operatively coupled between a rotatable driving member of the front input section and one of the intermediate drive members. The endless drive member remains substantially in a single plane during shifting of the drive members on the intermediate drive axle.

Abstract: A shift control apparatus is provided for a bicycle having a plurality of front sprockets and a plurality of rear sprockets, wherein a front derailleur shifts a chain among the plurality of front sprockets and a rear derailleur shifts the chain among the plurality of rear sprockets. The apparatus comprises a shift unit that provides signals for shifting the front derailleur and the rear derailleur; and a prohibiting unit operatively coupled to the shift unit and providing signals so that the chain is prohibited from engaging at least one of i) a laterally innermost front sprocket in combination with a laterally outermost rear sprocket, and ii) a laterally outermost front sprocket in combination with a laterally innermost rear sprocket.

Abstract: A process for controlling the transmission of a cycle having one or more gear sprockets is provided. The gear sprockets include one or more angular positions in which shifting of the gears is facilitated. A sensor is provided to detect the one or more angular positions of the gear sprocket in which gear shifting is facilitated. The sensor is selectively activated according to a command request to initiate a shift.

Abstract: A control apparatus for an electrically operated bicycle transmission comprises a power supply sensor and a control unit operatively coupled to the power supply sensor. The power supply sensor senses a power characteristic of a power supply, and the control unit provides a signal to operate the bicycle transmission when the power characteristic falls below a predetermined value. Alternatively, the control apparatus comprises a running condition time sensor and a control unit operatively coupled to the running condition time sensor. The running condition time sensor senses a time interval of a running condition of a bicycle, and the control unit provides a signal to operate the bicycle transmission to a predetermined gear ratio when the time interval of the running condition passes a selected value.

Abstract: An integrally formed gear set with a plurality of gears comprises a first, a second and a third gear. Each gear has a plurality of teeth and a plurality of recess portions. The teeth and recess portions are alternatively arranged. The first, second and third gears are formed by a sheet which is firstly formed as a stepped structure containing three layers which are the first gear, second gear and third gears; the rings between two gears are formed with a plurality of teeth which are bent to be at the same plane of the second and third gears.

Abstract: A power saving apparatus is provided for an assisting apparatus that uses power from a rotating member to assist the operation of a bicycle transmission. The power saving apparatus comprises a rotating member engaging member that moves between a rotating member engaging position and a rotating member disengaging position, a setting mechanism that sets the rotating member engaging member toward the rotating member engaging position, and a power saving unit. The power saving unit saves power communicated between the setting mechanism and the rotating member engaging member when the setting mechanism attempts to move the rotating member engaging member into the rotating member engaging position and the rotating member engaging member encounters a force that resists the rotating member engaging member being in the rotating member engaging position.

Abstract: A bicycle gear-shift actuator (10, 100) having an articulated quadrilateral support (11) with four connecting rods (21, 22, 23, 24) hinged together by four pin elements (41, 42, 43, 44), and a motor member (12), having a variable length output shaft that travels along a drive axis (13) between two opposite pin elements (41, 42) to move them for deforming the articulated quadrilateral (11). Preferably, the drive axis (13) perfectly intersects the pin axis (32) of at least one (42) of the two pin elements (41, 42).

Abstract: Chain guides for the front sprockets of bicycles are disclosed. More particularly, the chain guides are adapted or configured for bicycles that have multiple (usually 2 or 3) sprockets/chain rings mounted to the crank assembly. The setup is provided to freely allow shifting between the gears. All of the chain guide variations presented are provided with an outer flange attached to a roller section so that these portions roll together with the chain they restrain. Additional optional features include aspects to do with roller positioning, bracket mounting, roller configuration and supplemental chain restrain means (including a stop/post member and inner roller flange.

Abstract: A method for shifting a bicycle transmission that includes a derailleur for shifting a chain among a plurality of sprockets. The transmission includes at least a first sprocket and a second sprocket, wherein at least one of the first sprocket and the second sprocket includes a shift facilitating structure to facilitate shifting the chain between the first sprocket and the second sprocket. The method comprises the steps of rotating a sensor element together with the plurality of sprockets, and activating the derailleur to shift the chain between the first sprocket and the second sprocket when the sensor element is located at a predetermined position relative to the derailleur.

Abstract: A front derailleur includes a fixed member, a chain guide and a linkage assembly. The fixed member has a mounting portion and a pair of mounting flanges axially spaced from each other. The linkage assembly is coupled between the chain guide and the fixed member to transversely move the chain guide. The linkage assembly includes first, second and third links. The first link is pivotally coupled to the fixed member for rotation about a first axis. The second link is pivotally coupled to the mounting flanges for rotation about a second axis. The third link is coupled to the chain guide and movably coupled to the first and second links to form a four-bar linkage together with the fixed member. The mounting flanges preferably have different axial widths. The second link preferably has a longitudinal dimension of least about 45.0 millimeters.

Abstract: A control apparatus is provided for a bicycle shift control device that uses power from a rotating member to assist the operation of a bicycle transmission, wherein the shift control device includes an input transmission member that requests assistance of the rotating member and an output transmission member that is assisted by the rotating member. The control apparatus comprises an input transmission member drive member that moves at least to a neutral position, to an upshift position and to a downshift position; an input drive member position sensor operatively coupled to the input transmission member drive member; and a motor operatively coupled to the input transmission member drive member. A control unit is operatively coupled to the input drive member position sensor and to the motor to move the input transmission member drive member to at least one of the neutral position, the upshift position and the downshift position.

Abstract: Front bicycle derailleur comprising an electrical motor controlling an actuating arm, consisting of an extension of an articulated arm of the derailleur, by means of a geared reduction transmission, comprising a worm screw and a sector gear, or a bevel pair.

Abstract: A bicycle shift control device includes a shift signal output unit for outputting shift signals and an inhibiting unit operatively coupled to the shift signal output unit for inhibiting the output of a second shift signal after the output of a first shift signal. In a more specific embodiment, the inhibiting unit inhibits the output of the second shift signal for a predetermined standby time after the output of the first shift signal.

Abstract: A transmission apparatus for a bicycle is capable of performing a transmission operation even while operating or running by the inertia of the bicycle. The transmission apparatus T for a bicycle includes a driving sprocket member rotationally driven by a crankshaft; a multi-stage driven sprocket member drivingly connected to the output shaft cooperatively engaged and rotated with the rear wheel; a chain applied over the driving sprocket member and the driven sprocket member; and a transmission changing-over mechanism M2 for positioning the chain among a plurality of transmission sprockets. The driven sprocket member is integrally arranged to always be rotated, and the one-way clutch for transmitting a rotation of the crankshaft to the driving sprocket member while in its normal rotating direction is arranged in the power transmitting path extending from the crankshaft to the driving sprocket member.

Abstract: A transmission apparatus is capable of retaining an endless transmission chain on a rotatable member, even where a small inter-axis distance remains between two rotatable shafts to which each of two rotatable members is drivingly connected. The transmission includes a drive sprocket member for connecting to a main drive shaft. The transmission also includes a driven sprocket member, connected to the output shaft in parallel with the main drive shaft and including a plurality of transmission sprockets. The transmission further includes a chain interconnecting both sprocket members, and a transmission shift mechanism for positioning the chain among the transmission sprockets. The drive sprocket member is supported at the main drive shaft in the rotary center line direction, in such a way that the chain is applied to both sprocket members in parallel with a plane crossing at a right angle with the rotary center line of the main drive shaft.

Abstract: A shift control apparatus is provided for a bicycle having a plurality of front sprockets and a plurality of rear sprockets, wherein a front derailleur shifts a chain among the plurality of front sprockets and a rear derailleur shifts the chain among the plurality of rear sprockets. The apparatus comprises a shift unit that provides signals for shifting the front derailleur and the rear derailleur; and a prohibiting unit operatively coupled to the shift unit and providing signals so that the chain is prohibited from engaging at least one of i) a laterally innermost front sprocket in combination with a laterally outermost rear sprocket, and ii) a laterally outermost front sprocket in combination with a laterally innermost rear sprocket.

Abstract: A front derailleur includes a fixed member, a chain guide and a linkage assembly. The fixed member has a mounting portion and a pair of mounting flanges axially spaced from each other. The linkage assembly is coupled between the chain guide and the fixed member to transversely move the chain guide. The linkage assembly includes first, second and third links. The first link is pivotally coupled to the fixed member for rotation about a first axis. The second link is pivotally coupled to the mounting flanges for rotation about a second axis. The third link is coupled to the chain guide and movably coupled to the first and second links to form a four-bar linkage together with the fixed member. The mounting flanges preferably have different axial widths. The second link preferably has a longitudinal dimension of least about 45.0 millimeters.

Abstract: A rotation direction detection apparatus is configured to detect the direction of rotation of a pulley that is rotatably mounted to a chain guide, and includes a rotation sensor, a detection element and a shielding mechanism. The rotation sensor is fixed to the chain guide. The detection element is mounted to the pulley such that it can be detected by the rotation sensor. The shielding mechanism has a shielding arm that is mounted to move between a shielding position where the rotation sensor cannot detect the detection element and a detection position where the rotation sensor can detect the detection element. The shielding mechanism has a linking member that moves the shielding arm in tandem with the rotation of the pulley in first or second rotational directions. The shielding mechanism has a positioning protrusion that positions the shielding arm at either the shielding position or the detection position.

Abstract: A derailleur comprises a base member including an engagement member for nonrotatably engaging the bicycle frame; a threaded member coupled to the base member for engaging a threaded shaft; a chain guide; and a coupling mechanism coupled between the base member and the chain guide so that the chain guide moves relative to the base member.

Abstract: A bicycle derailleur comprises a mounting member adapted to be mounted to a bicycle frame, a base member pivotably mounted relative to the mounting member, a biasing mechanism that biases the base member clockwise relative to the mounting member when viewed laterally outwardly from the base member, a chain guide and a coupling mechanism coupled between the base member and the chain guide so that the chain guide moves relative to the base member. A rotation restricting mechanism is disposed in a force communicating path between the mounting member and the base member to restrict counterclockwise rotation of the base member relative to the mounting member.

Abstract: A structure of an automatic speed change device for bicycle gearbox is disclosed in this present invention. The above-mentioned design can be applied to a bicycle with a rear wheel speed change device. According to this invention, the automatic speed change device is able to control the allotting device of the rear wheel speed change device to transfer the chain into suitable gear by the treading rat of the user. This design can simplify the manual gear shifting process in the prior art for controlling the rear wheel speed change device. Therefore, this invention can make riding bicycle more easily and widely for all age.

Abstract: A process for controlling the transmission of a cycle having one or more gear sprockets is provided. The gear sprockets include one or more angular positions in which shifting of the gears is facilitated. A sensor is provided to detect the one or more angular positions of the gear sprocket in which gear shifting is facilitated. The sensor is selectively activated according to a command request to initiate a shift.

Abstract: A motorized bicycle actuator assembly has a motorized actuator unit arranged to operate a bicycle component. The motorized actuator unit has a drive train coupled to a reversible motor, and a position switch device or an overcurrent detecting circuit coupled to the motor to stop rotation of a drive axle of the drive train at first and second stop positions. The bicycle component is coupled to the drive axle to move a movable member between a first and second preset component positions that correspond to the first and second stop positions of the drive axle, respectively. First and second shock absorbing elements are arranged to cushion the drive train when the drive axle moves past the first and second stop positions of the drive axle, respectively.

Abstract: A derailleur includes a base member, a movable member coupled for moving relative to the base member and supporting a chain guide, a first actuating unit for moving the movable member relative to the base member, and a second actuating unit for moving the first actuating unit. In one embodiment, the second actuating unit includes a wire winding surface, and a position adjuster is provided for adjusting a relative position between the first actuating unit and the second actuating unit. In another embodiment, the second actuating unit comprises a first actuating member movably coupled to a second actuating member, and a position adjuster is provided for adjusting a relative position between the first actuating unit and the second actuating unit. Alternatively, a position adjuster is provided for adjusting a relative position between the first actuating member and the second actuating member.

Abstract: A shift control device is provided for a bicycle that uses shift control signals from a signal provider to operate an automatic shifting mechanism of a bicycle transmission, wherein the shift control signals correspond to a traveling condition. The shift control device comprises an override shift command unit for providing an override shift command, and a simulation unit operatively coupled to the override shift command unit for providing simulated shift control signals in response to the override shift command.

Abstract: A drive train for a bicycle includes a housing mounted in a bicycle frame with a pedal assembly attached to a drive shaft fixably mounting a plurality of different diameter drive elements, the drive shaft is journalled in and between the housing cover plates. A driven shaft is also journalled in and between the housing cover plates. The driven shaft mounts a plurality of rotatably unfixed different diameter driven elements, with the driven shaft rotationally coupled to a bicycle rear wheel. A plurality of connection elements rotationally couples the plurality of different diameter drive elements to the different diameter driven elements, wherein a single connection element rotatably couples a single drive element to a single driven element being in alignment. Also, a structural assembly for rotatably engaging a selected single driven element to the driven shaft to establish a selected rotational ratio between the drive shaft and the driven shaft.

Abstract: A motorized bicycle gear shift device comprising a derailleur and an electric motor, associated directly with the derailleur, for controlling the derailleur and an electric transducer of absolute type, also associated with the derailleur for producing an electric signal indicative of the absolute position of the movable body of the derailleur.

Abstract: A derailleur system for bicycle is constructed to include an annular plate holding at least two gears, a bracket assembly rotated to a center hole of the annular plate to hold a transmission shaft, a driven gear wheel set pivoted to the transmission shaft and having a driven gear wheel meshed with one of the gears, a control device connected to a derailleur cable of the bicycle, and a driven member for selectively controlling the engagement between the driven gear wheels of the driven gear wheel set with the transmission shaft subject to the position of the control device.

Abstract: Front bicycle derailleur comprising an electrical motor controlling an actuating arm, consisting of an extension of an articulated arm of the derailleur, by means of a geared reduction transmission, comprising a worm screw and a sector gear, or a bevel pair.

Abstract: Chain guides for the front sprockets of bicycles are disclosed. More particularly, the chain guides are adapted or configured for bicycles that have multiple (usually 2 or 3) sprockets/chain rings mounted to the crank assembly. The setup is provided to freely allow shifting between the gears. All of the chain guide variations presented are provided with an outer flange attached to a roller section so that these portions roll together with the chain they restrain. Additional optional features include aspects to do with roller positioning, bracket mounting, roller configuration and supplemental chain restrain means (including a stop/post member and inner roller flange.

Abstract: An assisting apparatus for using power from a rotating member to assist the operation of a bicycle transmission includes a mounting unit; an input transmission member coupled to the mounting unit, wherein the input transmission member moves to at least a neutral position, to an upshift position and to a downshift position; and an output transmission member coupled to the mounting unit, wherein the output transmission member moves to at least a first output position and a second output position. A rotating member engaging member moves between a rotating member engaging position and a rotating member disengaging position, and a motion transmitting mechanism transmits motion from the rotating member engaging member to the output transmission member. A switching mechanism moves the rotating member engaging member to the rotating member engaging position when the input transmission member is in at least one of the upshift position and the downshift position.

Abstract: A shift control device includes a mounting unit; a transmission control element movably mounted to the mounting unit, wherein the transmission control element moves between a first transmission control position and a second transmission control position; a first transmission control element biasing mechanism for biasing the transmission control element toward the first transmission control position; and a first shift control element that moves between a first shift control position and a second shift control position. The first shift control element and the transmission control element are operatively coupled such that the transmission control element moves toward the second transmission control position when the first shift control element moves toward the second shift control position, and the transmission control element moves toward the first transmission control position as the first shift control element continues to move toward the second shift control position.

Abstract: A power saving apparatus is provided for an assisting apparatus that uses power from a rotating member to assist the operation of a bicycle transmission. The power saving apparatus comprises a rotating member engaging member that moves between a rotating member engaging position and a rotating member disengaging position, a setting mechanism that sets the rotating member engaging member toward the rotating member engaging position, and a power saving unit. The power saving unit saves power communicated between the setting mechanism and the rotating member engaging member when the setting mechanism attempts to move the rotating member engaging member into the rotating member engaging position and the rotating member engaging member encounters a force that resists the rotating member engaging member being in the rotating member engaging position.

Abstract: A bicycle shift control device is provided for a transmission actuating member, wherein the transmission actuating member moves to a plurality of transmission actuating positions for moving a bicycle transmission to a plurality of transmission positions. The shift control device comprises an operator attachment element that moves among a first operator attachment position, a second operator attachment position, and a third operator attachment position for causing an operation of the transmission actuating member. The second operator attachment position is disposed on a first path of movement from the first operator attachment position, and the third operator attachment position is disposed on a second path of movement from the first operator attachment position. The first path of movement is different from the second path of movement.

Abstract: A shift control apparatus for a bicycle comprises an output transmission member that moves to at least a first output position and a second output position, a position maintaining mechanism, and a release control mechanism. The position maintaining mechanism includes a position maintaining member that moves between a position maintaining position and a position release position, wherein the position maintaining position maintains the output transmission member in one of the first output position and the second output position. The position release position allows the output transmission member to move toward the other one of the first output position and the second output position. The release control mechanism includes a release member that moves between a first release member position and a second release member position.

Abstract: A shift control device is provided for controlling a transmission control member coupled to a bicycle transmission. The device comprises an actuating component that is manually operated by a rider, wherein the actuating component moves to an actuating component neutral position, to an actuating component upshift position and to an actuating component downshift position. A first biasing component biases the actuating component toward one of the upshift position and the downshift position, and a neutral positioning component positions the actuating component in a neutral position.

Abstract: A sensor retainer for a bicycle sprocket assembly includes an annular member for mounting and rotating coaxially with the bicycle sprocket assembly and a sensor element fixed to the annular member. Alternatively, the sensor retainer may include a fixing member for mounting a derailleur or other transmission to a bicycle frame and a sensor element mounted to the fixing member.

Abstract: An automatic derailleur device comprises an arm, a sprocket roller meshed with one of a set of different-sized sprocket wheels on, a control member, a tension wheel meshed with a sprocket chain and secured to the arm, a cylinder including a shaft secured to the arm, an intermediate collar on the shaft, an elastic member on the shaft and biased between the collar and the cylinder, and a hollow cylindrical block with the shaft passed through, and a pump in the cylinder and including a piston rod rotatably coupled to the sprocket roller, a plurality of blades extended from the piston rod, and a cylindrical passage formed between the cylinder and the block. The sprocket chain is shiftable from a meshing with a largest sprocket wheel to a smallest sprocket wheel automatically as the bicycle is accelerating from a stop or low speed to a high speed and vice versa.