Abstract: A sprocket of a chain transmission for a bicycle is described, intended to be coupled with a further sprocket with a smaller diameter in a group of sprockets integral in rotation. The sprocket comprises a plurality of teeth which follow each other on the sprocket separated by spaces according to a direction of rotation of the sprocket, in which each tooth has a thickness, a width and a height and has a lead side, a following side, a front side and a rear side. The sprocket has a front bevel on at least one tooth of first disengagement of said plurality of teeth and a rear bevel (60) on at least one tooth of last engagement of said plurality of teeth.

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: An annular plate, which is of a first material and has a toothed external periphery, is shrink fitted onto the perimeter of a disc of a second material so that there is no play between the annular plate and the disc. The perimeter of the disc includes at least one radially recessed region and the annular plate has its inner edge provided with corresponding one or more protruding regions which fit thereto. A plurality of fasteners, such as grub screws, are inserted axially at spaced intervals between the annular plate and the disc.

Abstract: A bicycle derailleur is provided with a chain guide that basically includes inner and outer guide plates, a guide pulley and a tension pulley. The tension pulley is rotatable about a rotation axis between free ends of the guide plates. The tension pulley has an annular recess disposed about the rotation axis to form a projection. The inner guide plate has a guide section with a radially outermost edge. Preferably, the outermost edge of the guide section is located in the annular recess, and the projection projects axially further from a center plane of the tension pulley than the outermost edge. Preferably, the chain guide includes a dust cap coupled between the inner guide plate and the tension pulley. Preferably, the outermost edge of the guide section is located radially inwardly of the projection and radially outwardly of the annular portion of the dust cap.

Abstract: A drive mechanism for a bicycle transmission assist mechanism includes a crank arm having a drive member. The drive member includes a first abutment facing a forward rotational direction of the crank arm and a non-concave sloped surface facing a rearward rotational direction of the crank arm.

Abstract: This invention concerns a sprocket gear for facilitating the derailing of the chain of a bicycle transmission and other prime movers. The sprocket gear includes at least two sprockets axially and concentrically positioned relative to one another. Each sprocket includes a perimeter, a front face, and a back face. Gear teeth project axially from at least a first perimeter segment of the front face and at least a second perimeter segment of the front face is free of gear teeth. Gear teeth project axially from the back face perimeter at the at least second segment of the front face. No gear teeth project from the back face perimeter at the at least first perimeter segment of the front face.

Abstract: A sprocket is provided having a plurality of teeth around its circumference. Adjacent teeth are separated by roots each having a root radius defined as the distance between the center of the sprocket and a point along the root closest to the sprocket center in a radial direction. In one aspect of the invention, the sprocket comprises at least two different root radii arranged in a pattern effective to redistribute tensions imparted to a chain by the sprocket at one or more predetermined sprocket orders.

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 sprocket includes a hub and a plurality of teeth projecting radially outwardly from the hub. At least one cushion ring is located adjacent the teeth, and the cushion ring defines a plurality of compression pads separated from each other by transverse grooves. Each of the compression pads is defined symmetrically about a circumferential mid-point. When part of a sprocket with symmetric tooth spaces, the cushion ring is being operable identically in first and second opposite rotational directions. In one arrangement, the compression pads each include a planar outer surface having a leading and a trailing end, wherein the leading end and trailing end are located a common radial distance from a center of the hub about which the sprocket rotates. The tooth spaces of the sprocket can be symmetric, asymmetric and the root surface can be relieved. The sprocket can include multiple tooth profiles distributed randomly about the hub.

Abstract: A sprocket is adapted to be mounted to a sprocket support that rotates around an axle. The sprocket comprises a sprocket body having a side surface and an inner peripheral surface defining a sprocket-mounting opening, wherein at least one portion of the inner peripheral surface is adapted to contact the sprocket support. At least one lateral projection extends laterally from the side surface of the sprocket body in close proximity to the at least one portion of the inner peripheral surface that is adapted to contact the sprocket support.

Abstract: A sprocket comprises a sprocket portion having a plurality of radially extending teeth, a first coupling portion extending from a first side of the sprocket portion and having a first coupling structure disposed on an inner peripheral surface thereof, and a second coupling portion extending from an opposite second side of the sprocket portion and having a second coupling structure disposed on an outer peripheral surface thereof. In another embodiment of a sprocket according to the present invention, a sprocket comprises a sprocket portion having a plurality of radially extending teeth, a first coupling portion extending from a first side of the sprocket portion and having a first coupling structure disposed on an inner peripheral surface thereof, and a second coupling structure disposed on an inner peripheral surface of the sprocket.

Abstract: A rear sprocket assembly has a plurality of sprockets with the smallest sprocket being a top or first sprocket. At least one of the teeth is a down shift tooth that has a recessed side surface to assist in shifting the chain to the next larger sprocket. Preferably, all of the teeth of the top sprocket are identical. The sprocket body of the top sprocket is threaded to be coupled to a freewheel or hub. A second sprocket is located adjacent the top sprocket and preferably cooperates with the top sprocket during a down shift from the top sprocket to the second sprocket. The second sprocket cooperates with a third sprocket during a down shift from the second sprocket to the third sprocket.

Abstract: An improved tooth profile for a roller chain sprocket enables noise reduction from impact and polygonal action during the meshing process. The profile of the engaging flank consists of three portions which are the seating, impact and distal portions all three of which are arcs with well-defined radii and arc centers. The profile of the disengaging flank is determined in accordance to a modified form of the JIS standard in which the sprocket pitch is smaller than the roller chain pitch. The impact point is located at the tangent point, thus permitting a gradual change of the roller velocity, thereby lessening the impact level and the effects of polygonal action.

Abstract: A rear sprocket assembly has a plurality of sprockets with the smallest sprocket being a top or first sprocket. At least one of the teeth is a down shift tooth that has a recessed side surface to assist in shifting the chain to the next larger sprocket. Preferably, all of the teeth of the top sprocket are identical. The sprocket body of the top sprocket is threaded to be coupled to a freewheel or hub. A second sprocket is located adjacent the top sprocket and preferably cooperates with the top sprocket during a down shift from the top sprocket to the second sprocket. The second sprocket cooperates with a third sprocket during a down shift from the second sprocket to the third sprocket.

Abstract: A sprocket support for a bicycle includes a first outer peripheral surface portion and a second outer peripheral surface portion. The first outer peripheral surface portion is adapted to support an inner peripheral surface of a first sprocket for rotation around an axis, wherein the first outer peripheral surface portion defines at least one radially inwardly extending spline and at least one radially outwardly extending spline. The at least one radially inwardly extending spline has a radially inner surface with a first radially inner distance from the axis, and the at least one radially outwardly extending spline has a radially outer surface with a first radially outer distance from the axis. The second outer peripheral surface portion is adapted to support an inner peripheral surface of a second sprocket for rotation around the axis, wherein the second outer peripheral surface portion defines at least one radially inwardly extending spline and at least one radially outwardly extending spline.

Abstract: A drive mechanism for a bicycle transmission assist mechanism includes a crank arm having a drive member. The drive member includes a first abutment facing a forward rotational direction of the crank arm and a non-concave sloped surface facing a rearward rotational direction of the crank arm.

Abstract: A pedal drive mechanism that provides continuous, uninterrupted torque to the drive chain or belt. The continuous torque effect is a result of establishing two separate but connectively joined axes of rotation that transmit pedal crank force to the drive chain (55). The assembly of a right pedal crank (29) rotative mounted about left pedal output crank (28) are connectively fastened (46) to the left pedal crank (38) through the bottombracket bearing (37) defines the first axis of rotation. The assembly of the chain sprockets (35, 34 and 33), sprocket interface (25) and sprocket support (24) are rotatively mounted by a sealed bearing (40) about a bearing inner race support (23) and eccentric flange (22) establish a second axis of rotation. The fixtures of these two axes of rotation are connectively joined by articulating links (26) with self-aligning sealed bearings (27).

Abstract: A crank shaft assembly includes a socket, a crank shaft, two roller bearings, two mounting portions, two covers, and two steel ball sets. Thus, the roller bearings and the steel ball sets are arranged in different axial directions to bear the forces of two different directions. In addition, the roller bearings and the steel ball sets are arranged in different axial directions to increase the force bearing area of the crank shaft assembly, thereby preventing from producing stress concentration, so as to increase the lifetime of the crank shaft assembly.

Abstract: This invention includes a sprocket assembly for facilitating the derailing of the chain of a bicycle transmission and other prime movers. The first embodiment of the invention relates to a sprocket gear having at least two sprockets axially and concentrically positioned relative to one another. Each sprocket includes a non-circular configuration having at least one long radius and at least one short radius. The sprockets being axially aligned adjacent to one another such that the short radius of one sprocket is axially substantially aligned with and substantially equal in length with said long radius of an adjacent sprocket. The second embodiment of the present invention provides a sprocket assembly having two sprockets with the tooth being displaced by less than one tooth relative to each other. Thus, it is possible to vary the relationship between the teeth of the small sprocket and the chain to engage these teeth without having to vary the phase relationship between the larger and smaller sprockets.

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: This invention comprises a sprocket gear for facilitating the derailing of the chain of a bicycle transmission and other prime movers. The sprocket gear having at least two sprockets axially and concentrically positioned relative to one another. Each sprocket includes a non-circular configuration having at least one long radius and at least one short radius. The sprockets being axially aligned adjacent to one another such that the short radius of one sprocket is axially substantially aligned with and substantially equal in length with said long radius of an adjacent sprocket. The sprockets include a perimeter, a front face, and a back face. Gear teeth project axially from at least a first perimeter segment of said front face and wherein at least a second perimeter segment of said front face is free of gear teeth.

Abstract: A tooth contour structure for large sprocket set of bicycle having at least three characteristic teeth arranged on a larger sprocket of two adjacent sprockets, wherein the right side of a first characteristic tooth has a curve surface and a cut portion. Between the first characteristic tooth and a second characteristic tooth a tooth valley bottom edge has a projection surface biased toward the smaller sprocket. The arc of a top edge of the projecting surface is formed according to the path and curvature of the upper chain. The top edge has a slant angle. A recession is formed below the first characteristic tooth.

Abstract: A sprocket assembly includes a sprocket body comprising: (i) first and second hubs that project axially outward from opposite first and second axial faces; and, (ii) a plurality of teeth that extend circumferentially in a row and that project radially outward between the first and second hubs. Each of the teeth includes a drive flank and a coast flank. The drive flank and coast flank of at least some of the teeth are shaped differently from each other so as to define an asymmetric tooth profile. First and second metal cushion rings are captured and float eccentrically on the first and second hubs, respectively. The teeth are identical or multiple asymmetric tooth profiles are used on a single sprocket body and arranged in a regular or irregular pattern. The root surface between successive teeth can be relieved so that a space is defined between the root surface and a roller that bridges the root.

Abstract: A bicycle crank assembly has a right crank crimp-fastened to a crank shaft in such a manner that the external appearance is attractive. The crank shaft has a first and second portions with the second portion being positioned on the right side of the first portion and having a larger diameter than the first portion. The right crank has a sprocket mounting part, a right crank arm part, and an engagement bore formed in the center of the sprocket mounting part. The right crank is crimp-fastened to the crank shaft by installing the second portion of the crank shaft into the engagement bore and pressing the periphery of the engagement bore toward the outside in the axial direction of the crank shaft such that the pressed portion bulges radially inward and an annular space is formed between the crank shaft and the engagement bore.

Abstract: A sprocket is adapted to be mounted to a sprocket support that rotates around an axle. The sprocket comprises a sprocket body having a side surface and an inner peripheral surface defining a sprocket-mounting opening, wherein at least one portion of the inner peripheral surface is adapted to contact the sprocket support. At least one lateral projection extends laterally from the side surface of the sprocket body in close proximity to the at least one portion of the inner peripheral surface that is adapted to contact the sprocket support.

Abstract: A sprocket support for a bicycle includes a first outer peripheral surface portion and a second outer peripheral surface portion. The first outer peripheral surface portion is adapted to support an inner peripheral surface of a first sprocket for rotation around an axis, wherein the first outer peripheral surface portion defines at least one radially inwardly extending spline and at least one radially outwardly extending spline. The at least one radially inwardly extending spline has a radially inner surface with a first radially inner distance from the axis, and the at least one radially outwardly extending spline has a radially outer surface with a first radially outer distance from the axis. The second outer peripheral surface portion is adapted to support an inner peripheral surface of a second sprocket for rotation around the axis, wherein the second outer peripheral surface portion defines at least one radially inwardly extending spline and at least one radially outwardly extending spline.

Abstract: A detachable freewheel turner for a bicycle mainly comprises a wrench formed with two through holes and a chain including a plurality of connectors, and at a end of the first connector formed with a hole, a junction plate connected to the two connectors which are adjacent to the hole, a pivot hole formed in the junction plate, the hole and pivot hole in the chain corresponding respectively to the through holes of the wrench. Two pins detachably extend through the through holes in the wrench and the hole and pivot hole in the chain, so as to secure the chain to the wrench.

Abstract: A sprocket assembly that includes at least three sprockets and a sprocket carrier having a plurality of radially extending carrier arms. The carrier arms include a first receiving surface and a second receiving surface opposite the first receiving surface. A first sprocket mounted to the first receiving surface and a second sprocket mounted to the second receiving surface. A third sprocket arranged between the first and second sprockets.

Abstract: A multi-speed gear system for a chain transmission device of a bicycle is provided. The system includes a disc having a front plate, a rear plate, and a plurality of tooth series concentrically arranged in the disc and a tooth series selector. Each of the tooth series has a plurality of tooth blocks; the front plate of the disc has a plurality of tooth holes; and the rear plate of the disc has a plurality of rear holes. Each of the tooth blocks is either pushed into a corresponding one of the tooth holes or protrude out of the front plate and the tooth series selector selects one of the tooth series to change speed and makes the tooth blocks of the selected tooth series protrude out of the front plate.

Abstract: A bicycle chain wheel assembly includes an outer ring made of Aluminum Alloy with teeth defined in an outer periphery thereof, and an inner ring made of composite material which is light in weight. The inner ring is securely connected to an inner periphery of the outer ring by rivets. The chain wheel has durable outer ring that is engaged with bicycle chain and light inner ring, so that the whole weight of the chain wheel is light and meets the requirement of a modern bicycle.

Abstract: A power transmission system used in connection with a vehicle power wheel of a bicycle or other vehicle which has a fixed axle and which utilizes a rotating chain sprocket engaging an endless chain for receiving an input torque and transmitting an output torque. The system includes a transmission cadence varying apparatus that is operably connected to the wheel by an endless chain. The transmission cadence apparatus incorporates a left crank arm fixedly secured to a spindle which is fixedly secured to a left drive plate which incorporates a radial slot for a cam post to travel. A post ring is eccentrically mounted relative to the spindle via ball bearing means on the post ring housing which is then fixedly secured to the bicycle bottom bracket frame. The post ring incorporates 2 cam posts that are rigidly mounted 180 degrees apart in which one of the cam post drives the left drive plate radial slot and the other cam post drives the right crank radial slot.

Abstract: A variable ratio sprocket assembly for providing improved transition between gears and eliminating derailing. The variable ratio sprocket assembly includes an axle, a bicycle wheel hub coupled to a rear wheel of the bicycle and designed to rotatably receive rotational force from a receiver, a receiver including a first diameter coupled to the bicycle wheel hub, a converter with a second diameter substantially greater than the diameter of the receiver slideably engages the receiver to provide a plurality of gear ratios with respect to the receiver, a driver includes a third diameter substantially greater than the second diameter of the converter and is slideably engaged by the converter such that rotating the driver in a first direction rotates the converter in a first direction which in turn rotates the receiver in a first direction which in turn rotates the rear bicycle wheel, and a sprocket coupled to an exterior surface of the driver designed for engaging a drive chain.

Abstract: A rear sprocket assembly has a plurality of sprockets with the smallest sprocket being a top or first sprocket. At least one of the teeth is a down shift tooth that has a recessed side surface to assist in shifting the chain to the next larger sprocket. Preferably, all of the teeth of the top sprocket are identical. The sprocket body of the top sprocket is threaded to be coupled to a freewheel or hub. A second sprocket is located adjacent the top sprocket and preferably cooperates with the top sprocket during a down shift from the top sprocket to the second sprocket. The second sprocket cooperates with a third sprocket during a down shift from the second sprocket to the third sprocket.

Abstract: The invention relates to a driving sprocket for a bicycle crankset having a toothed ring whose ring is divided into a plurality of segments (14a, 14b, 14c, 14d), the segments being borne by a frame (16) that is rotationally movable about a crankset axle, each sprocket segment being movable between a low position and a high position, a system for transferring each segment to transfer said segment from one position to another, and an indexing mechanism to control the system for shifting the segments. The sprocket is characterized in that each segment (14a, 14b, 14c, 14d) is floatingly mounted with respect to the frame (16) and in that it is guided in its transfer movement along a trajectory having a radial component and a tangent component.

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: The invention relates to a compact installation gear with, for instance, a ⅜″ derailleur chain and a derailleur for setting a transmission ratio between a crankshaft and a rear hub of a bicycle. To that end, the gear comprises a compact housing with the crankshaft included therein, with a slidable driving first sprocket engaging, via the derailleur chain, a selected second sprocket which forms part of a series of second sprockets mutually different in diameter, located on a secondary shaft with a third sprocket mounted thereon outside the housing, which, in turn, via a roller chain, drives a fourth sprocket on the rear hub. The transmission ratio can be set with the aid of the derailleur by moving the derailleur chain over the different second sprockets while at the same time moving the driving first sprocket to a position directly opposite the selected second sprocket.

Abstract: A sprocket (10) of a chain transmission for a bicycle is described, intended to be coupled with a further sprocket (3) with a smaller diameter in a group of sprockets integral in rotation. The sprocket (10) comprises a plurality of teeth (13) which follow each other on the sprocket (10) separated by spaces (14) according to a direction of rotation (R) of the sprocket (10), in which each tooth (13) has a thickness, a width and a height and has a lead side (31), a following side (32), a front side (33) and a rear side (34).

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: Projections colliding with constricted portions at the center of hourglass-shaped pin link plates and with constricted portions at the center of hourglass-shaped roller link plates are provided at an annular resilient body. When a roller chain starts to mesh with a sprocket, constricted portions at the centers of hourglass-shaped link plates of the roller chain can be pushed radially outwards from the sprocket by the projections of the resilient body, vibrations occurring at the roller chain meshing with the sprocket can be made small, vibrations at each part of the roller chain can be made small, collision speed when rollers of the roller chain collide with teeth bottoms of the sprockets can be reduced, and the generation of noise can be suppressed. Moreover, because hourglass-shaped link plates are used, the roller chain can be made lighter than when flat oval shaped or oval shaped link plates are used.

Abstract: A sprocket ring has outwardly protruding spaced teeth to engage the motorcycle drive chain and an inner circular flange to interconnect with the sprocket hub. The sprocket hub has an outer circular flange to interconnect with the sprocket ring. Mating holes in the flanges receive bolts therethrough to interconnect the ring and the hub.

Abstract: An improved tooth profile for a roller chain sprocket enables noise reduction from impact and polygonal action during the meshing process. The profile of the engaging flank consists of three portions which are the seating, impact and distal portions all three of which are arcs with well-defined radii and arc centres. The profile of the disengaging flank is determined in accordance to a modified form of the JIS standard in which the sprocket pitch is smaller than the roller chain pitch. The impact point is located at the tangent point, thus permitting a gradual change of the roller velocity, thereby lessening the impact level and the effects of polygonal action.

Abstract: A sprocket comprises a sprocket portion having a plurality of radially extending teeth, a first coupling portion extending from a first side of the sprocket portion and having a first coupling structure disposed on an inner peripheral surface thereof, and a second coupling portion extending from an opposite second side of the sprocket portion and having a second coupling structure disposed on an outer peripheral surface thereof. In another embodiment of a sprocket according to the present invention, a sprocket comprises a sprocket portion having a plurality of radially extending teeth, a first coupling portion extending from a first side of the sprocket portion and having a first coupling structure disposed on an inner peripheral surface thereof, and a second coupling structure disposed on an inner peripheral surface of the sprocket.

Abstract: A fastener system for attaching bicycle chainrings to a bicycle crank comprised of a nut and a bolt. Both the nut and bolt consist of shafts with flanges on one end. The nut has threads formed on the interior of its shaft, while the bolt has threads formed on the exterior of its shaft. The nut and bolt can thus be threadedly engaged with each other to clamp the chainrings to the crank. Both the nut and bolt contain tool engagement interfaces formed on the interior of their respective shafts.

Abstract: An adjustable cam shaft sprocket for allowing small adjustments to a cam shaft. The adjustable cam shaft sprocket comprises an inner member and an outer member, the inner member being placed concentrically within said first circular member and held in place by a fastener. A series of openings located at the perimeter of the inner member and outer member are arranged such that only one pair of openings between the inner member and the outer member are aligned for each hole alignment. A shear pin is inserted through the aligned pair of openings to prevent the inner member from rotating with respect to the outer member. A small adjustment to the cam shaft is achieved by removing the shear pin, rotating the inner member with respect to the outer member so that a second pair of openings is aligned, and re-inserting the shear pin.

Abstract: A sprocket assembly is provided for a bicycle having a large sprocket and a small sprocket. The large sprocket includes one or more chain support projections formed on the side surface opposed to the small sprocket. Each projection includes a contact portion defming a contact surface for contacting, without meshing, a lower end of a chain shifted from the small sprocket to the large sprocket. The projections are arranged on the large sprocket with a size and shape that allows the projections to pass between outer links prior to the gear-changing operation. The chain support projections are arranged for causing the contact surface to contact the chain engaging the small sprocket and pick up the chain radially outwardly of the large sprocket during a chain shift from the small sprocket to the large sprocket.

Abstract: A tooth contour structure for large sprocket set of bicycle, at least three characteristic teeth are arranged on the larger sprocket of two adjacent sprockets for the large sprocket set, wherein the right side of the first characteristic tooth has a curve surface and a cutting portion fulfilled with a moving path for a chain, and between the first characteristic tooth and second characteristic tooth a tooth valley bottom edge is a projection butting surface formed by stamping and biased toward the smaller sprocket, and the arc of the top edge for the butting surface is formed according to the path and curvature of the upper chain, and the top edge is also formed into a slant angle, and a recession is arranged below the first characteristic tooth, not only the process is easy; the manufacturing cost is low; the chaining-up path is steady and smooth; the fixed-point shifting can be proceeded; but also the shifting efficiency is raised; the reliability is increased; the usage life is prolonged; and the running n

Abstract: In a combination structure of sprocket set and rivet, the rivet includes a head part and a drum bolt part. Two sprockets are connected and secured into one body by arranging the bolt part into a penetration-through hole between adjacent sprockets and by applying methods of stamping and riveting on the bolt part. The head part of the rivet is also arranged with a recessed internal hexagonal hole seat to make its outline resemble as an internal hexagonal screw. On the outline, by comparison with a prior rivet that only has a monotonous flat head part, the internal hexagonal hole seat of the head part of the rivet of the present invention not only further has a sense of beauty and a feeling of high added-value, but also it can have an auxiliary positioning function during the processes of stamping and riveting to make the processes of stamping and riveting be more solid and its connection strength more strong.

Abstract: A sprocket combination includes two or more sprocket devices each having one or more sprockets extended from a hub. The side portions of the sprocket devices may be engaged or secured together with a peripheral bulge-and-peripheral recess engagement, and without additional calibrating process. One or more fasteners may further be engaged through the sprocket devices for further solidly securing the sprocket devices together. The smallest sprocket device may be made of stronger materials, and the other sprocket devices may be made of lighter and softer materials.

Abstract: A bicycle chain guide device includes a plate mounted to the crank axle has two protrusions and each of the protrusions has a first roller and a second roller connected thereto. The chain engaged with a chainwhell passes between the first roller and the second roller on each of the two protrusions.

Abstract: A chainwheel assembly includes a chainwheel having a guard member connected to a first side thereof and an annular groove is defined between the chainwheel and the guard member. A diameter of the guard member is larger than a diameter of the chainwheel. An axle integrally extends from a second side of the guard member and a crank integrally connected to the guard member.