Bicycle front shifting system

Abstract

A bicycle front shifting system includes operable to transmit a wireless signal, a crank assembly with two crank arms and a pedal on each of the two crank arms. The crank assembly is rotatable about a rotation axis. A front shift unit is coupled to the crank assembly and is rotatable about the rotation axis. The front shift unit includes a chain ring component with a big chain ring and a small chain ring. The small chain ring has a small diameter and the big chain ring has a big diameter that is larger than the small diameter. A shift mechanism is coupled to and rotatable with the chain ring component about the rotation axis. The shift mechanism is configured to receive the wireless signal from the shifter and to shift a chain between the big chain ring and the small chain ring according to the wireless signal.

Description

[Technical Field]

[0001] This patent relates to and asserts priority to U.S. Provisional Application No. 62 / 754,312, filed November 1, 2018, and U.S. Provisional Application No. 62 / 801085, filed February 4, 2019. The entire contents of these prior applications are hereby incorporated by reference.

[0002] This disclosure relates generally to a front derailleur system for a bicycle, and more particularly to a front derailleur system incorporated as part of a crank assembly of a bicycle. [Previous Technology]

[0003] A bicycle typically includes a system for driving a chain on the bicycle to provide power to the system. A drive system typically includes a front-drive and a rear-drive system.

[0004] Derailleur systems for bicycle rear sprockets and front chainrings are known in the art. These derailleur systems typically use a front or rear derailleur to move the chain from one sprocket or chainring to another. A typical front or rear derailleur is mounted on a fixed part of the frame of a bicycle. A rear derailleur is typically mounted on or directly adjacent to the rear wheel fork end of the bicycle frame. Therefore, the frame often has a bracket at the fork end for attaching the rear derailleur.

[0005] A conventional front-drive system includes a crank assembly. The crank assembly may include two crank arms connected by a spindle. The crank assembly may also include one or more drive sprockets. When using two or more drive sprockets, various techniques are available for switching the chain from one drive sprocket to another.

[0006] The most common techniques involve using a front derailleur, such as a front derailleur typically mounted on a bicycle frame, which includes plates positioned on both sides of the chain to drive the chain between the drive sprockets. The front derailleur is usually mounted on the seatpost or other component of a bicycle frame immediately before the crank assembly chainrings. Therefore, an open, accessible position must be provided on the seatpost frame to accommodate a front derailleur clamped onto the tube. In some cases, a mounting bracket is provided on the bicycle frame for attaching the front derailleur to the frame. The driving technique of the front derailleur can produce a coarse drive shift between the drive sprockets and can cause problems when shifting under load.

[0007] Existing front derailleurs present several other problems, deficiencies, or disadvantages for bicycles, including frame designers. For example, frame designers must consider the mounting location of the front derailleur when designing a bicycle frame with a front derailleur system. Therefore, a portion of the frame must be accessible and positioned relatively close to the front chainrings. This requirement to fit a portion of the bicycle into the frame imposes design constraints on the designer. When the front derailleur is mounted on the bicycle frame, it may be incorrectly positioned relative to the front chainrings. This reduces the quality and effectiveness of front derailleur operation and may cause shifting instability, particularly when the chain is under heavy load.

[0008] Furthermore, mounting the front derailleur to a portion of the bicycle frame makes the frame effectively part of the front derailleur system. When riding a bicycle, the frame bends under stress. Any movement or bending of the frame at the front derailleur mounting location or at the location between the mounting location and the attachment points of the front chainrings can cause shifting problems. For example, a rider may attempt to shift gears while the frame is bent, resulting in misalignment between the front derailleur and the front chainrings. This misalignment can further cause poor shifting quality, causing the chain to derail or allowing the chain to slip during shifting. This misalignment can also prevent shifting from being performed, especially under heavy loads.

[0009] Conventional front derailleur designs also make installation and bicycle assembly more difficult, time-consuming, and / or expensive. The installer must take several necessary steps, including separately obtaining the clamps or fasteners, the necessary tools, and the derailleur, and then mounting the front derailleur onto the bicycle frame. The installer or another person adjusting or assembling the bicycle must then properly position and align the front derailleur relative to the front chainrings during system assembly. This assembly is difficult for those lacking special skills and training. Proper positioning and alignment of the front derailleur relative to the front chainrings is necessary to ensure adequate shifting capability. [Summary of the Invention]

[0010] In one example, a bicycle front derailleur assembly is provided. The front derailleur assembly includes: a front derailleur unit configured to couple with a crank assembly for rotation about a rotation axis therewith, the front derailleur unit having a chain link assembly and a shifting mechanism coupled to the chain link assembly. The chain link assembly has: a large chain link having a plurality of teeth defining a large chain link plane; and a small chain link having a plurality of teeth defining a small chain link plane, the small chain link having a small diameter and the large chain link having a large diameter larger than the small diameter. The shifting mechanism includes at least one protruding shifting element disposed in a transition region between the large chain link and the small chain link, the shifting mechanism being configured to allow axial movement of the at least one protruding shifting element between the large chain link plane and the small chain link plane.

[0011] In one example, a front derailleur unit for a bicycle is provided. The front derailleur unit includes a chain link assembly having a large chain link and a small chain link engaged together for rotatable about a rotation axis. The large chain link has a large diameter and a plurality of large chain sprocket teeth, and the small chain link has a small diameter and a plurality of small chain sprocket teeth. The large diameter is larger than the small diameter. The front derailleur unit also includes a shifting mechanism coupled to the chain link assembly. The shifting mechanism includes an electronic control unit, a gear motor unit, at least one upshift element, at least one downshift element, and a power source configured to provide power to the electronic control unit and the gear motor unit to operate the at least one upshift element and the at least one downshift element. The at least one upshifting element is disposed in a transition region between the small sprocket teeth and the large sprocket teeth, and can be axially moved by the electronic control unit and the gear motor unit to switch a chain from the small sprocket teeth on the small sprockets to the large sprocket teeth on the large sprockets. The at least one downshifting element can be operated by the electronic control unit and the gear motor unit to switch a chain from the large sprocket teeth on the large sprockets to the small sprocket teeth on the small sprockets.

Implementation Method

[0076] This disclosure relates to a front derailleur system for bicycles and a bicycle having the front derailleur system. The disclosed front derailleur system and bicycle solve or improve upon the aforementioned and / or other problems and disadvantages of conventional front derailleur systems and bicycles. The disclosed front derailleur system is completely integrated into the chain link assembly, and no parts are separately attached to the bicycle frame. Because the designers do not need to house a portion of the front derailleur system on the frame, this gives frame designers greater design freedom. The disclosed front derailleur system therefore also eliminates the possibility of incorrectly positioning a portion of the front derailleur system relative to the chain links. Because the bicycle frame is not part of the front derailleur system, any bending of the frame during use will not cause any problems during shifting, thus improving shifting performance. The disclosed front derailleur system can also be installed on bicycle frames not designed for mounting a front gear shifter or derailleur. The disclosed front derailleur system provides smooth and consistent shifting even under heavy chain loads. These disclosed transmission systems are easier to install and assemble than a conventional front gear changer or transmission, and require no special skills or training. Those skilled in the art will understand these and other purposes, features, and advantages of the disclosed wheel assembly and trainer by reading this disclosure.

[0077] Those skilled in the art will understand that the drawings and detailed descriptions provided herein are for illustrative purposes only and not for limiting the scope of the invention or disclosure. The appended claims define the scope of the invention and disclosure. The following detailed description may use terms such as "first," "second," "third," "top," "bottom," "left," "right," "front," and / or "rear." These terms are used only for clarity and generally only to distinguish multiple parts and components having the same name. Unless specifically stated herein, the use of these terms is not intended to limit the scope of this disclosure to a particular order, configuration, or orientation of such parts and components. Furthermore, unless specifically stated herein, these terms refer to multiple bicycle mechanisms conventionally mounted on a bicycle and the bicycle being oriented and used in a standard manner.

[0078] Furthermore, multiple embodiments of the transmission system and bicycle prior to the disclosure are disclosed and described herein. Each embodiment may have one specific combination of multiple morphologies, components, assemblies, functions, or forms. The scope of this disclosure is not intended to be limited to these specific combinations. The disclosed morphologies, components, assemblies, functions, and forms may be used independently of each other or in other combinations not specifically disclosed or described herein.

[0079] The exchange or speed change of a chain between two or more sprockets can be achieved by moving at least one ("1") speed-changing element into one of the chains of a drive system. The speed-changing element may be a plurality of protruding speed-changing elements and may be axially movable relative to one of the sprockets' rotational axes. The protruding speed-changing elements may be configured to extend and / or retract axially to move into and / or out of the chain. The at least one movable speed-changing element may be radially disposed between the root circle of one tooth of a larger sprocket and the tip of one tooth of a smaller sprocket. The at least one movable speed-changing element may include an array of one or more protruding speed-changing elements. The array of protruding speed-changing elements may be disposed at different radial distances relative to the larger and / or smaller sprockets.

[0080] A chain can be switched or changed in speed between two or more sprockets by using a downshifting element from a larger sprocket to a smaller sprocket, and the downshifting element can be configured as a sliding or inclined plane that can be moved into and / or out of the chain on the larger sprocket to allow the chain to slide or change speed toward the smaller sprocket.

[0081] A device for a bicycle drivetrain may include a plurality of movable shifting elements. These movable shifting elements may be disposed on a chain link structure. A device for a bicycle drivetrain may include a plurality of movable downshifting elements. These movable downshifting elements may include an inclined surface configured to be movable into a chain of a large chain link. A device for a bicycle drivetrain may include a plurality of electronic and / or electrical components configured to control and / or operate the shifting elements. These electronic and / or electrical components may be disposed on a chain link structure. These electronic and / or electrical components may include an electric motor, an electric linear actuator, a solenoid, or other electrical device operable to produce action or movement. In one example, the electric motor or other electrical device is configured to move the shifting elements.

[0082] Referring below to the figures, Figure 1 shows an example of a bicycle 100, which has: a frame 102; a front wheel 104 coupled to a front fork 106 of the frame; and a rear wheel 108 coupled to a plurality of rear seat forks 110 and a plurality of rear chainstays 112 on the frame. The wheels 104 and 108 support the frame 102 above a surface, and the bicycle 100 is movable on the surface in a forward direction indicated by the arrow "A". The bicycle 100 has a handlebar assembly 114 mounted on a front tube 116 of the frame 102. The bicycle 100 also has a seat 118 supported by a seatpost 120, and the seatpost 120 is housed in a seat tube 122 of the frame 102.

[0083] The bicycle 100 has a multi-gear transmission 124, which has one or both of a front gear changer (hereinafter further referred to as a front derailleur system) and a rear gear changer mounted on the frame 102. The gear changer may be, for example, an electromechanical derailleur including a rear derailleur 126 and one of the front derailleur systems described in detail below. The gear changer can be operated using one or more gear derailleurs 128, which may be mounted on the handlebar assembly 114. The gear derailleurs 128 may be operated, as in the disclosed example, via wireless communication or via a physical connection using a mechanical shift cable or hydraulic cable (not shown). The transmission 124 includes a plurality of chain links as described in detail below, and the chain links are driven by a crank assembly 132 having two crank arms 134 and two pedals 136 respectively. The chain links are connected to the frame 102 and to a plurality of sprockets on the rear wheel 108 by a chain 138. These plurality of sprockets can be referred to as a rear sprocket assembly 140 mounted on the frame 102 and coaxial with the rear wheel 108. Apart from these sprockets and the front derailleur system, the bicycle 100 described above is conventional and is shown in Figure 1 as a mountain bike. Those skilled in the art will understand that the types and models of bicycles may differ from the disclosed example. For example, a road bicycle with a drivetrain having a down-handlebar and a road-type gear system with a road gear range could be used instead of a mountain bike or other bicycle gear range.

[0084] In this example, the bicycle 100 includes a braking system. The braking system includes at least one brake lever 142 movably connected to the handlebar assembly 114. The brake lever 142 is configured to operate multiple components of the braking system of the bicycle 100. In one example, the braking system may include one or both of a hydraulically or cable-actuated front brake mechanism 144 coupled to the front wheel 104 via a hydraulic or mechanical cable 146 and a hydraulically or cable-actuated rear brake mechanism (not shown) coupled to the rear wheel 108 via a hydraulic or mechanical cable 148. As described above, the braking system may be one or both of a hydraulically actuated system and a mechanically actuated system, and both are known in the art.

[0085] Figures 2 and 3 show several substantial parts of a front derailleur system of a bicycle 100 configured according to the teachings of this disclosure, and are shown from the right side of the bicycle. The front derailleur system includes a front derailleur unit 150. The crank arm 134 of the crank assembly 132 is carried as part of the front derailleur unit 150 around which the chain 138 passes, as shown in Figure 2. Figure 3 shows the same view of the front derailleur system, but with the chain 138 removed. As detailed below, the front derailleur unit 150 also carries all the components of the previously disclosed derailleur system except for the gear derailleur 128 or the wireless actuator. Because the wireless gear derailleur 128 of the front derailleur system must be easily accessible to one of the riders of the bicycle 100, it is not carried on the front derailleur unit 150. As mentioned above, the gear derailleur 128 can be remotely mounted on the handlebar assembly 114 of the bicycle 100.

[0086] Figures 4 to 6 show perspective views, left-side views, and edge views of various parts of the front derailleur system and front derailleur unit 150 shown in Figures 2 and 3. In this example, the front derailleur unit 150 has two links 152 and 154 fixedly connected and concentric to rotate together about one of the rotation axes R of the front derailleur unit. The links 152 and 154 are rotatably and torsionally engaged with one of the crank arms 134 through an interlocking keyway connection 156. The crank arm 134 is held on the front derailleur unit 150 by a plurality of screws 158, and the screws 158 have threads that assemble to engage threaded holes (not shown) surrounding the keyway connection 156 in the crank assembly. The screws 158 and the keyway connection 156 may differ from the example shown and may be replaced by other suitable fasteners and connection configurations. The crank arm 134 can be torsionalally engaged and fastened to a conventional spindle (not shown) in a manner known in the art. The spindle can be rotatably housed by a plurality of ball bearings (not shown) of a base bracket, which is mounted on the frame 102 of the bicycle 100. Therefore, the front derailleur unit 150 can rotate relative to the base bracket about the axis of rotation R.

[0087] Figures 7 to 9 show several diagrams of a small segment of the chain 138. In a typical configuration, the chain 138 may be formed by a plurality of inner and outer links joined together. The inner links are formed by a plurality of pairs of inner plates 164, which define a narrower tooth space 166 between the plates. The outer links are formed by a plurality of outer plates 168, which define a wider tooth space 170 between the plates. The plates 164, 168 and the links are joined together by a plurality of rivets or pins 172 of the width of the links and the chain 138. The rivets 172 may each selectively carry a roller 174 disposed between the plates and may include a bushing (not shown) between the roller and the rivet.

[0088] The chain 138 can engage any link 152, 154 and surround its circumference. Link 152 has a relatively large diameter and can be referred to as a large link as is known in the art. The large link 152 has a plurality of sprocket teeth 160 spaced apart and surrounding its periphery or circumference. Link 154 has a smaller diameter than the large link 152 and can be referred to as a small link as is known in the art. The small link 154 has a plurality of sprocket teeth 162 spaced apart and surrounding its periphery or circumference. The chain 138 engages the sprocket teeth 160 of the large link 152 or the sprocket teeth 162 of the small link 154. In this example, the small link 154 is positioned inside or to the left of the large link 152. As shown in Figures 4 and 6, the sprocket teeth 160 of the large link 152 can be configured to have alternating narrow teeth 160n and wide teeth 160w. Similarly, the sprocket teeth 162 of the small chain link 154 can be configured to have alternating narrow teeth 162n and wide teeth 162w. Therefore, the teeth 160 and 162 surrounding each chain link 152, 154 can alternate between narrow teeth 160n or 162n for fitting into the narrower tooth spaces 166 between the inner plates 164 and wide teeth 160w or 162w for substantially filling the wider tooth spaces 170 between the outer plates 168 of the chain 138. By pedaling in a rotational direction P through the crank arms 134, the front derailleur unit 150 and the chain 138 rotate, thereby driving one of the rear sprockets of the rear sprocket assembly 140 to propel the bicycle 100 forward in the direction of arrow A in Figure 1.

[0089] Referring again to Figures 2 to 6, a cover or fairing 180 is securely attached to the outside or right side of the front derailleur unit 150 by a plurality of screws 182 or other suitable fasteners or methods. The fairing 180 is sized to cover a substantial portion of the outside of the front derailleur unit 150 and is shaped to be smooth and rounded or spherical to reduce aerodynamic drag on the forward movement of the bicycle. The inherent structure of the fairing 180 (as opposed to being primarily an aerodynamic cover) is designed to increase the strength and rigidity of the front derailleur unit 150. Furthermore, the fairing 180 can be configured to keep road debris away from the more sensitive parts of the front derailleur unit 150 and prevent the rider from accidentally contacting these sensitive parts.

[0090] The main components of the front derailleur system on the front derailleur unit 150 will be described below. More specific details of the main components, various other sub-components, and auxiliary components according to the teachings of this disclosure will then be explained. The functions and operations of the main components, sub-components, and auxiliary components will then be explained. Finally, the shifting function and operation of the front derailleur system will also be explained below. Typically, the front derailleur system includes multiple components assembled and configured to shift the chain 138 between the large sprocket 152 and the small sprocket 154 according to a rider's selective operation of the derailleur 128. The disclosed front derailleur system allows the chain 138 to upshift from the small sprocket 154 to the large sprocket 152 and downshift from the large sprocket to the small sprocket. Upshifting and downshifting are performed smoothly and quickly by the disclosed front derailleur system and using the multiple components fully disposed on the front derailleur unit 150.

[0091] First, referring to Figures 3 and 10 to 12, the front derailleur system includes a control unit 184, which may be a waterproof electronic device. The control unit 184 is attached to the front derailleur unit 150 by a plurality of screws or other fasteners 186. In this example, the control unit 184 is attached to the outside or right side of the chainring 152. The control unit 184 includes a printed circuit board (PCB). The PCB may include a radio and antenna, a microprocessor, and spring-biased electrical connectors. In use, the radio and antenna can send shifting commands to a rider-controlled actuator, such as the aforementioned derailleur 128, and receive shifting commands from the derailleur 128, which may be mounted on the handlebar assembly 114 of the bicycle 100. The radio and antenna can also be used to communicate with the electronic rear derailleur 126. The microprocessor can receive, process, and send electronic signals. The microprocessor, radio, and antenna may be housed within a waterproof housing or enclosure 188 of the control unit 184.

[0092] The control unit 184 may also have a button 190 and a light-emitting diode (LED) 192 or other light-emitting element exposed on the housing 188. The button 190 may be an electronic switch actuated by the rider. The button 190 can be used to pair the control unit 184 of the front derailleur unit 150 with the derailleur 128 on the handlebar assembly 114 and selectively to pair the control unit 184 and thus the front derailleur unit 150 with the electronic rear derailleur 126. The LED 192 may be a multi-color LED, such as a red-green-blue (RGB) LED or a red-green-blue-white (RGBW) LED. The LED can therefore produce three colors of light and be configured to provide visual feedback to the rider to indicate the status of the front derailleur system. Alternatively, the printed circuit board may also include an electronic audio or noise transmitter that can provide audible feedback to the rider.

[0093] Referring to Figures 10 to 12, the front derailleur system includes a power source 194, which may be one of the rechargeable power sources described herein, for providing power to operate the front derailleur system. In this example, the power source 194 is attached to the housing 188 of the control unit 184. A latch 196 can be configured and actuated to allow the power source 194 to be quickly and easily installed, removed, and replaced by a rider without the use of a tool. The power source 194 may be a lithium-ion rechargeable power source or, if necessary, another suitable power source. When the power source 194 is attached to the housing 188 of the control unit 184, the power source is in electrical contact with the spring-biased electrical connectors and can supply power to the PCB.

[0094] Referring further to Figures 10 to 12, the front derailleur system also includes a gear motor unit 200, which may be a waterproof electromechanical device. In this example, the gear motor unit 200 is mounted on the right or outside of the large chain link 152. The gear motor unit 200 can be attached to a bracket 204 carried on the outside of the large chain link 152 by means of a plurality of screws 202 or other suitable fasteners. The bracket 204 can be similarly attached to or mounted on the large chain link 152 by means of similar fasteners or screws. Alternatively, the bracket 204 can be formed as an integral part of the large chain link 152 or an integral part of the housing of the gear motor unit 200 in order to reduce the number of components to be assembled from three to two. The gear motor unit 200 may include an electric motor (not shown) and a gear train (not shown). The gear train can be configured to reduce speed and increase power output, i.e., the output torque generated by the electric motor of the gear motor unit 200. The gear train is located within and connected to the gear motor unit 200, and drives the rotation of one of the mechanical output portions of the gear motor unit 200. The gear motor unit 200 may also include an angular position sensing system (not shown) for sensing the angular position of the mechanical output portion of the gear motor unit 200. The gear motor unit 200 receives power and electrical signals from the control unit 184, and this can be done via a cable (not shown).

[0095] The front derailleur system also includes a chain guard or guide rail 206 attached to the large sprocket 152 on the right or outer side. The chain guide rail 206 can be attached to the large sprocket 152 by means of screws 208 or other suitable fasteners. The size and position of the chain guide rail 206 are configured to guide the chain 138 as needed during use and when shifting gears to help prevent the chain 138 from derailing to the outside of the large sprocket 152. The chain guide rail 206 is positioned adjacent to the sprocket teeth 160 and separated from the sprocket teeth 160 to the outside. The chain guide rail 206 serves as an outer-direction barrier for the chain 138.

[0096] The front derailleur system further includes an upshift element 210 mounted on the large sprocket 152. In this example, the upshift element 210 is located on the right side or outside of the large sprocket 152 and is pivotable relative to the outside around its lower edge. In one example, the upshift element 210 may be made of aluminum, making the element lightweight yet robust and durable. In one example, the upshift element 210 may be cast aluminum. The upshift element 210 is configured to selectively guide the chain 138 to the sprocket teeth 160 of the large sprocket 152 by the sprocket teeth 162 of the small sprocket 154, as further detailed below. In another example, the upshift element 210 may be injection molded from a nylon material or a long-fiber reinforced thermoplastic material. As described below, the various components of the upshift element 210 may also be individually attached to the upshift element 210 or may be molded or otherwise formed as integral parts of the element.

[0097] The front derailleur system also includes at least one downshifting element carried on the right side or outside of the large chain link 152. In this example, the front derailleur system includes two such elements, each including a first downshifting element 212a and a second downshifting element 212b, each pivotable relative to the outside around its central portion. In one example, the first and second downshifting elements 212a and 212b are arranged approximately 180 degrees apart around the circumference of the front derailleur unit 150. In one example, the first and second downshifting elements 212a and 212b may also be formed of aluminum, making each element lightweight yet robust and durable. In one example, the first and second downshifting elements 212a and 212b may be cast aluminum. Similar to the upshifting element 210, in another example, the downshifting elements 212a and 212b may be injection molded from a nylon material or a long-fiber reinforced thermoplastic material.

[0098] In the disclosed example, the first downshift element 212a and the second downshift element 212b have the same construction and configuration. Therefore, only one downshift element is shown or described in detail. However, it should be understood that such illustrations and descriptions are equally applicable to either the first and second downshift elements 212a and 212b. The first and second downshift elements 212a and 212b are generally configured to selectively guide the chain 138 to the sprocket teeth 162 of the small sprocket 154 by the sprocket teeth 160 of the large sprocket 152, as further detailed below. As will be understood from the following description, the front derailleur system may include only one downshift element or may include two or more downshift elements if desired.

[0099] Referring below to Figures 10, 11, and 13, in this example, the output torque from the electric motor of the gear motor unit 200 is transmitted to the mechanical output portion of the gear motor unit. The mechanical output portion of the gear motor unit 200 is generally referred to herein as a motor output 214, which may be in the form of an output shaft or a disc, elbow plate, or horn coupled to the output shaft via a keyway interface or other suitable connection. In this example, the motor output 214 may be axially fastened to the gear motor unit 200 by a screw or other suitable fastener (not shown). A hub 216 may also be attached to the output portion 214 by a screw 218 or other suitable fastener. The hub 216 may be a disc or other suitable device for connecting the gear motor unit 200 to other components of the front transmission system. In this example, the hub has a circumferential groove 217 formed around its periphery. A first link 220a and a second link 220b are connected to the hub 216. Each link 220a and 220b is a relatively thin, long element with a hole at each end. The hub 216 also has two holes formed through it and can be configured to be 180 degrees opposite each other around the circumference of the hub. The proximal ends of the first link 220a and the second link 220b are received in the groove 217 and their holes are aligned with one of the corresponding holes in the hub 216. A first pin 222a and a second pin 222b are substantially cylindrical and are received through the corresponding holes in the hub 216 and in the proximal ends of each link 220a and 220b. The pins 222a and 222b are axially held by a retaining ring 224 to secure the proximal ends of the links 220a and 220b to the hub 216. In this manner, the first link 220a is rotatably attached to the hub 216 via the first pin 222a, and the second link 220b is rotatably attached to the hub 216 via the second pin 222b. The hub can move the first and second links 222a and 222b by rotation of the gear motor unit 200, as further described below.

[0100] Figures 14 to 16 show perspective and plan views of what is defined herein as a chain link assembly 228, which includes a large chain link 152 and a small chain link 154. As shown, the right side or outer side of the large chain link 152 and components of the front derailleur system are removed. In this example, the outer side of the large chain link 152 has a surface 226 on which a plurality of optional morphologies are provided. These optional morphologies may each be integrally formed as an integral part of the surface 226 of the large chain link 152 by a cutting, casting or other suitable process. Alternatively, a plurality of these optional morphologies may be formed as separate components and attached to the surface 226 of the large chain link 152 by welding, riveting, screwing or other suitable fasteners or attachment techniques. In one example, the surface 226 may include a shallow concave plane 230 sized and structured to accommodate a housing 188 of the control unit 184. The plane 230 can help provide an easily identifiable mounting location for proper positioning of one of the control units 184 when mounted on the plane 230. In another example, the surface 226 may be sized and constructed to accommodate a shallow motor recess 232 of one of the gear motor units 200. As described above, the brackets 224 may be integrally formed as part of the surface 226 or may be separately attached to the surface 226 and adjacent to the motor recess 232.

[0101] Furthermore, a shallow pocket portion 234 may be formed with a semi-circular shape to provide one of the clearance depths of the surface 226 for the hub 216. The pocket portion 234 may be formed adjacent to the brackets 224 but on the opposite side of the brackets relative to the motor recess 232. The recessed first and second channels 236a and 236b may be formed to extend from the pocket portion 234 in opposite directions to receive the first and second links 220a and 220b (see also FIG. 13). The surface 226 also includes an upshift recess 238, which is formed with a semi-circular shape and receives the upshift drive and actuator assembly as described below. A shaft support 240 is positioned adjacent to the upshift recess 238 and includes an inner bore 242 extending through the support as described below for receiving a shaft. The surface 226 further includes a first downshift recess 244a, which is also formed to be semi-circular and accommodates a first downshift drive assembly as described below. A shaft support 246 is positioned adjacent to the first downshift recess 244a and includes an inner bore 248 extending through the support for receiving a shaft as described below. The upshift recess 238 and the first downshift recess 244a are positioned laterally separated on the surface 226. The equiaxed supports 240 and 246 are positioned such that their respective inner bores 242 and 248 are concentrically aligned. Furthermore, the upshift recess 238 is connected to the first channel 236a such that the first link 220a can extend along the first channel from the hub pocket 234 to the upshift recess 238.

[0102] The outer surface 226 of the large link 152 further includes a second downshift recess 244b, which is also formed to be semi-circular and accommodates a second downshift drive assembly as described below. A pair of separate shaft supports 250 are positioned adjacent to each other on opposite sides of the second downshift recess 244b. Each shaft support 250 includes an inner hole 252 extending through it for receiving a shaft, as described below. The shaft supports 250 are positioned so that they pass through the second downshift recess 244b such that the inner holes 252 are concentrically aligned. Furthermore, the second downshift recess 244b is connected to the second channel 236b such that the second link 220b extends along the second channel from the pocket portion 234 to the second downshift recess 244b.

[0103] The surface 226 also includes a first downshift element recess 254a, which is positioned above and separate from the first downshifter recess 244a. The shape and structure of the first downshift element recess 254a are configured to accommodate the first downshift element 212a as described below. A pair of separate shaft supports 256 are positioned adjacent to and on opposite sides of the first downshift element recess 254a. Each shaft support 256 includes an inner bore 258 extending through the support for receiving a shaft, as described below. The shaft supports 256 are positioned such that the inner bores 256 are concentrically aligned with each other via the first downshift element recess 254a. The surface 226 further includes a second downshift element recess 254b, which is positioned below and separate from the second downshifter recess 244b. The second drop element recess 254b is shaped and structured to accommodate the second drop element 212b as described below. A pair of separate shaft supports 260 are positioned adjacent to and on opposite sides of the second drop element recess 254b. Each shaft support 260 includes an inner bore 262 extending through the support for receiving a shaft, as described below. The shaft supports 260 are positioned such that the inner bores 262 are concentrically aligned with each other via the second drop element recess 254b.

[0104] As described above, since the first and second downshifting elements 212a and 212b have the same structure, the first and second downshifting element recesses 254a and 254b also have the same structure. However, the downshifting element recesses 254a and 254b do not necessarily have the same structure and may be different depending on the requirements or needs of a specific application.

[0105] Finally, the large chain link 152 has a series of holes 264a to d, configured to accommodate a portion of the lifting element 210 as described below. These holes 264a to d are arranged in an arc and are separated from each other along a circumferential direction on the large chain link 152. These holes 264a to d also have progressively different sizes and are arranged such that each successive hole is radially away from the axis of rotation R. In this example, hole 264a is closer to the axis of rotation R and is the larger of the holes. Each successive hole 264b to d is smaller than the previous hole and farther away from the axis of rotation R. More specifically, hole 264b is smaller than hole 264a and farther away from the axis of rotation R. Hole 264c is smaller than hole 264b and farther away from the axis of rotation R. Hole 264d is smaller than hole 264c and farther away from the axis of rotation R. In this example, there are four holes 264a to d in this series. Those with ordinary knowledge in the relevant technical field will understand that this number may vary.

[0106] Referring to Figures 17 and 18, the upshift element 210 is shown separate from the front derailleur unit 150. In this example, the upshift element 210 has a body 270 with certain channels 272 formed through the material of the body. These channels 272 can be used to remove material from the body 270 to reduce the weight of the upshift element 210 and the material used to form the upshift element 210. The body 270 has an inward side 274 with a series of mutually coplanar contact surfaces 276 located on a chain link contact plane C. A series of inner holes 278a to e are provided to pass through or within the body 270 of the upshift element 210. These series of holes 278a to e are arranged in an arc along the upshift element 210. In this example, there are five such inner holes 278a to e in this series. Those with ordinary knowledge in the relevant technical field will understand that this number may vary.

[0107] In this example, four of the series of inner holes 278a to d are each configured to accommodate a chain guide pin 280. A fifth inner hole 278e is configured to accommodate a chain lifter hook 282. In this example, the chain guide pins 280 and the chain lifter hook 282 are each secured to the body 270 of the lifter element 210 within the respective inner holes 278a to e by a series of corresponding fixing screws 284. The fixing screws 284 are exposed along a top edge of the body 270, and this top edge generally continues the arc of the series of inner holes 278a to e. The fixing screws 284 can be used to adjust and maintain an angular or rotatable position and an axial insertion or depth position of the chain guide pins 280 and the chain lifter hook 282 relative to the body 270 of the lifter element 210.

[0108] Referring to Figures 19 to 22, the construction of each chain guide 280 may be identical, and therefore only one chain guide is described in detail here. In this example, the chain guide 280 has a cylindrical end 286 and a speed-changing element 288 (or hook 288 or tooth 288) protruding axially from the end in the form of a hook or tooth. The cylindrical end 286 is sized and structured to fit into one of the inner holes 278a to d. The hook 288 has an inclined top surface 290 and the cylindrical end 286 has an inclined top 292 adjacent to the inclined top of the hook (see Figure 22). Therefore, as described below, the inclined top surface 290 and the inclined top 292 are positioned to converge and meet between the cylindrical end 286 and the hook 288 and are assembled to contact the chain 138. The hook 288 also has an inclined bottom surface 294 opposite to and parallel to the inclined top 292. The hook 288 further has a plurality of chamfers 296a to 296c on the tip of the hook and on a plurality of edges.

[0109] Referring to Figures 23 to 26, the chain shifter 282 may differ from the chain guides 280. In this example, the chain shifter 282 has a cylindrical end 300 and a shifting element 302 (or hook 302) protruding axially from the end in the form of a hook. The cylindrical end 300 is sized and structured to fit within an inner hole 278e in the body 270 of the shifting element 210. The hook 302 is L-shaped and partially separate from the cylindrical end 300 (see Figure 26). The hook 302 has a chamfer 304 at its tip facing the cylindrical end 300. The second protruding shifting element 302 is configured to contact and engage the chain 138 as described below. The second protruding transmission element 302 also has a chamfer 306 at its bottom, which is away from the cylinder end 300 and opposite to and parallel to the chamfer 304 at the hook tip. The hook 302 also has a plurality of chamfers 308a to 308c on the hook tip and on a plurality of edges.

[0110] In this example, the chain guides and chain lifters 280 and 282 are each formed of hardened steel to obtain wear resistance, durability, and strength. However, if desired, these bolts and hook elements can be formed of other suitable materials. In another example, if desired, the lifter element 210 and the chain guides and chain lifters 280, 282 can be formed as a single unit from the same material. Furthermore, each chain guide bolt 280 can be formed as an independent element so that the hook has a different desired depth. In addition, the inner holes 278a to e can each be blind holes, and the cylindrical ends 286, 300 can each have a different length to automatically set the depth of each chain guide and chain lifter bolt or element during installation. The cylinders and inner holes can also be assembled into multiple shapes that automatically set the rotational position of each bolt during installation. Furthermore, each inner hole can have a different size to assist in installing the correct bolt element in the correct inner hole on the lifter element 210.

[0111] As shown in FIG. 17, the chain guide pins 280 and the chain lift pins 282 are arranged in an alternating, gradually receding insertion depth relative to the contact surface 276 on the body 270, from the inner hole 278a to the inner hole 278e. More specifically, the inclined top surface 290 of each consecutive chain guide pin 280 from the inner hole 278a to the inner hole 278d and the tip of each hook 288 are closer to the plane C of the contact surface 276 than the former. Similarly, the chamfer 304 and the tip of the hook 302 of the chain lift pin 282 in the inner hole 278e are closer to the plane C than the adjacent hook 288 of the chain guide pin 280 in the inner hole 278d. The purpose of this pin and hook arrangement will be explained in detail below.

[0112] The shifting element 210 also has a pair of shaft heads 310 that are separated along and protrude from one of the bottom edges of the body 270. Each shaft head 310 has a through hole 312 oriented in a direction parallel to the length of the body 270. The through holes 312 of the shaft heads 310 are concentrically aligned with each other. The body 270 also has an adjustable fixing screw 314 that extends through the shifting element 210 in width or depth. The adjustable fixing screw 314 is screwed into and engaged in a screw hole passing through the body 270. The purpose and function of the fixing screw 314 are described in detail below.

[0113] As described above, the first and second downshifting elements 212a and 212b have the same configuration and construction in this example. Figures 27 to 29 show a slightly more detailed description of the first downshifting element 212a. The description also applies to the second downshifting element 212b, and therefore each is shown and represented herein with the same shapes and symbols. In this example, the first downshifting element 212a includes a body 320 having a proximal end, a distal end, and a pivot point 322 generally disposed between the ends. A pair of coaxial holes 324 are separately disposed through a width of the body 320 and define a pivot P at the pivot point 322.

[0114] The body 320 includes a drive arm 326 along one side of the body. The drive arm 326 extends radially relative to the shaft P and through a hole 324 in the fulcrum 322. In this example, the free end of the drive arm 326 is the proximal end of the body 320. A radial surface of the drive arm 326 defines a cam surface 328 of the downshifting element 212a. The cam surface 328 includes a notch 330. The other end of the body relative to the drive arm 326 terminates at the distal end. The other end has two legs 332 extending radially relative to the shaft P and through a hole 324 in the fulcrum 322. A head 334 is connected to the distal end of the legs 332. The proximal end of the head 334 connected to the legs 332 is thicker than the legs to define a wavy surface 336 radially inward toward the fulcrum shaft P (see FIG. 28). However, the wavy surface 336 has a non-flat profile and is oriented at an angle, i.e., it is not parallel to the axis P (see Figures 27 and 29). The head 334 also defines a contact surface 338 on one of the tangential surfaces of the head. The contact surface 338 is inclined relative to a radial reference between the axis P and the distal end of the first drop element 212a, i.e., it is not parallel. The contact surface 338 is configured to engage the chain 138 as described in more detail below.

[0115] In one example, the first and second downshifting elements 212a and 212b may be made of anodized aluminum. In another example, these elements may be made of other lightweight, cheaper, and / or less durable materials. However, in this example, the head 334 or at least its contact surface 338 may be separately made of a more durable, wear-resistant material, such as hardened steel, and attached to the head or body 320 of the downshifting element.

[0116] Referring to Figures 30 and 31, the upshift element 210 of the front transmission system is connected to two upshift drive assemblies that move the upshift element, as described in more detail below. In this example, one of the upshift drive assemblies is an upshift driver 340 shown in Figure 30. The upshift driver 340 has a cylindrical hub 342 with a central bore 344 axially passing through it. The upshift driver 340 rotates about the axis of the central bore 344. Two torque protrusions 346 protrude axially from one face 347 of the hub 342. The torque protrusions 346 are wedge-shaped and positioned 180 degrees opposite each other around the central bore 344. The torque protrusions 346 are configured to transmit torque in use as described below.

[0117] One drive body 348 of the upshift drive 340 protrudes radially from the hub 342 relative to the axis of the central hole 344. A connecting hole 350 is formed through the drive body 348. The connecting hole 350 has an axis parallel to but radially separated from the axis of the central hole 344. A threaded hole 352 is formed radially in the hub 342 and oriented perpendicular to the axis of the central hole 344. A portion of the drive body 348 forms a first elastic contact surface 354, which is assembled and configured to engage a torsion spring or a return spring as described below. In this example, the first elastic contact surface 354 is radially inward toward the axis of the central hole 344 but located in a plane separated from or tangential to the axis.

[0118] In this example, another upshift drive assembly is an upshift actuator 360 shown in Figure 31. This upshift actuator 360 also has a cylindrical hub 362 with a central bore 364 axially extending through it. The upshift actuator 360 rotates about the axis of the central bore 364. Two torque protrusions 366 axially protrude from a face 368 of the hub 362. These torque protrusions 366 are also wedge-shaped and positioned 180 degrees relative to each other around the central bore 364. The face 368 of the upshift actuator 360 contacts the face 347 of the upshift driver 340, and the torque protrusions 366 are configured to rotatably engage the torque protrusions 346 on the upshift driver 340 to transmit torque as described below during use.

[0119] One drive arm 370 of the upshift actuator 360 protrudes radially from the hub 362 relative to the axis of the central bore 364. A contact surface 372 on the drive arm 370 faces a circumferential direction. This contact surface 372 is configured to contact a portion of the upshift element 210 so as to move the element during use, as described in further detail below. A portion of the drive arm 370 forms a second resilient contact surface 374, which is configured to engage a torsion spring or a return spring as described below. In this example, the second resilient contact surface 374 faces radially inward toward the axis of the central bore 364 but is located in a plane separated from or tangential to the axis.

[0120] Referring to Figures 32 and 33, the first downshift element 212a of the front transmission system is connected to two downshift drive assemblies that move the first downshift element, as described in more detail below. In this example, one of the downshift drive assemblies is a first downshift driver 380 shown in Figure 32. The first downshift driver 380 also has a cylindrical hub 382 with a central bore 384 formed axially through the hub. The first downshift driver 380 also rotates about the axis of the central bore 384. Two torque protrusions 386 protrude axially from one face 388 of the hub 382. The torque protrusions 386 are wedge-shaped and positioned 180 degrees opposite each other around the central bore 384. The torque protrusions 386 are configured to transmit torque in use as described below.

[0121] A protrusion 390 of the first downshift drive 380 protrudes radially from the hub 382 relative to the axis of the central bore 384. A threaded hole 392 is formed radially in the hub 382 and oriented perpendicular to the axis of the central bore 384. The undercut portion of the protrusion 390 forms a first elastic contact surface 394, which is assembled and configured to engage a torsion spring or a return spring as described below. In this example, the first elastic contact surface 394 is radially inward toward the axis of the central bore 384 but is located in a plane that is separated from or tangential to the axis.

[0122] In this example, another downshift drive assembly is a first downshift cam 400 as shown in Figure 33. The first downshift cam 400 has a cylindrical hub 402 with a central bore 404 formed axially through the hub. The first downshift cam 400 rotates about the axis of the central bore 404. Two torque protrusions 406 protrude axially from a face 408 of the hub 402. The torque protrusions 406 are also wedge-shaped and positioned 180 degrees relative to each other around the central bore 404. The face 408 of the first downshift cam 400 contacts the face 388 of the first downshift driver 380, and the torque protrusions 406 are configured to rotatably engage the torque protrusions 386 on the first downshift driver 380 to transmit torque as described below during use.

[0123] One cam arm 410 of the first downshift cam 400 protrudes radially from the hub 402 relative to the axis of the central bore 404. A cam surface 412 on the cam arm 410 faces outwardly in a radial direction at the end of the cam arm. The cam surface 412 is curved and can be concentric with the axis of the central bore 404 and configured to contact a portion of the first downshift element 212a so as to move the element in use as described in further detail below. An undercut portion of the cam arm 410 forms a second elastic contact surface 414, which is configured and engaged with a torsion spring or a return spring as described below. In this example, the second elastic contact surface 414 also faces radially inward toward the axis of the central bore 404 but is located in a plane that is separated from or tangential to the axis.

[0124] Referring to Figures 34 and 35, the second downshift element 212b of the front transmission system is connected to two downshift drive assemblies that move the second downshift element, as described in more detail below. In this example, one of the downshift drive assemblies is a second downshift driver 420 shown in Figure 34. The second downshift driver 420 also has a cylindrical hub 422 with a central bore 424 axially passing through it. The second downshift driver 420 also rotates about the axis of the central bore 424. Two torque protrusions 426 protrude axially from one face 428 of the hub 422. The torque protrusions 426 are also wedge-shaped and positioned 180 degrees opposite each other around the central bore 424. The torque protrusions 426 are configured to transmit torque in use as described below.

[0125] A protrusion 430 of the second downshift drive 420 protrudes radially from the hub 422 relative to the axis of the central hole 424. A connecting hole 432 is formed through the protrusion 430. The connecting hole 432 has an axis parallel to but radially separated from the axis of the central hole 424. An undercut portion of the protrusion 430 forms a first elastic contact surface 434, which is assembled and configured to engage a torsion spring or a return spring as described below. In this example, the first elastic contact surface 434 is radially inward toward the axis of the central hole 424. A curved portion of the first elastic contact surface 434 is curved and concentric with the axis of the central hole 424 but separated from the hub 422. A straight portion of the first elastic contact surface 434 is located in a plane that is separated from or tangential to the axis. A groove 436 is provided in the protrusion 430 and extends in a plane perpendicular to the axis of the connecting hole 432. The groove 436 also has a depth, thereby completely cutting across the connecting hole 432, thus effectively dividing the connecting hole 432 into two coaxial holes, one on each side of the groove 436.

[0126] In this example, another downshift drive assembly is a second downshift cam 440 shown in Figure 35. This second downshift cam 440 is substantially similar to the first downshift cam 400 and therefore also has a cylindrical hub 442 with a central bore 444 axially extending through it. The second downshift cam 440 rotates about the axis of the central bore 444. Two torque protrusions 446 project axially from a face 448 of the hub 442. These torque protrusions 446 are also wedge-shaped and positioned 180 degrees relative to each other around the central bore 444. The face 448 of the second downshift cam 440 contacts the face 428 of the second downshift driver 420, and the torque protrusions 446 are configured to rotatably engage the torque protrusions 426 on the second downshift driver 420 to transmit torque as described below during use.

[0127] One of the cam arms 450 of the second downshift cam 440 protrudes radially from the hub 442 relative to the axis of the central bore 444. A cam surface 452 on the cam arm 450 faces outwardly in a radial direction at the end of the cam arm. The cam surface 452 is curved and concentric with the axis of the central bore 444, and is configured to contact a portion of the second downshift element 212b so as to move the element during use, as further detailed below. An undercut portion of the cam arm 450 forms a second resilient contact surface 454, which is configured to engage a torsion spring or a return spring as described below. In this example, the second resilient contact surface 454 also faces radially inward toward the axis of the central bore 444, but is located in a plane separated from or tangential to the axis.

[0128] The following provides combinations or installation configurations of the various components described above. It is helpful to refer to several different figures consecutively throughout the following description of the combined components of the front transmission unit 150. Specific figures are shown below when describing the components of the combined front transmission unit 150. However, other figures may also be of interest, although not specifically mentioned.

[0129] Referring to Figures 10 to 13, a first camshaft 460 extends between a shaft support 240 adjacent to the upshift recess 238 and a shaft support 246 adjacent to the first downshift recess 244a on the large chain link 152 (see Figures 14 and 15). The first camshaft 460 extends through the inner holes 242 and 248 of the corresponding shaft supports 240 and 246 (see Figures 14 and 16). A fastener such as a snap ring or a retaining ring 462 (see Figure 10) can be used at at least one end or both ends of the first camshaft 460 to axially hold the shaft and prevent it from being pulled out through the inner holes 242 and 248 of the shaft supports 240 and 246.

[0130] Referring to Figures 10 to 13, the shifting element 210 is rotatably supported on the first camshaft 460 and between the equiaxed supports 240 and 246. More specifically, the first camshaft is housed through a hole 312 in a shaft head 310 on the bottom edge of the body 270 of the shifting element 210. Referring also to Figures 5, 13 to 15, 18, 36 and 37, the series of inner holes 278a to d in the shifting element 210 are aligned with the series of holes 264a to d in the large chain link 152. Therefore, the teeth 288 on the chain guide pin 280 placed in the inner holes 278a to d of the body 270 of the shifting element 210 are positioned to be aligned with the corresponding holes 264a to d in the large chain link 152. Furthermore, referring to Figures 5, 14, 15, 36, and 37, the guard rail 206 mounted on the large chain link 152 includes an inner hole 264e radially positioned outside the large chain link 152. The hook 302 on the chain lift bolt 282, placed in the inner hole 278e of the body 270 of the lift element 210, is positioned to be aligned with the corresponding hole 264e in the guard rail 206.

[0131] As shown in Figures 5, 14, 15, 36, and 37, the large chain link 152 includes a gap 464 between the sprocket teeth 160 on the periphery of the chain link. The hole 264e in the guard rail 206 is positioned to align with the gap 464. Therefore, the hook 302 of the chain lift hook 282 is also aligned with the gap 464. As described below, the series of holes 264a to d are arranged in an arc and are separated from each other on the large chain link 152 in a circumferential direction. The series of holes 264a to d are also gradually arranged such that each consecutive hole is radially away from the axis of rotation R, with hole 264a being closer to the axis of rotation R and hole 264d being farther away from the axis of rotation. The hole 264e is positioned to continue the same arc, thereby being farther away from the axis of rotation R than the adjacent hole 264d. In this example, hole 264e in the guard rail 206 creates a fifth hole in the series of holes in the large chain link 152. Furthermore, those skilled in the art will understand that this number may vary.

[0132] When the shifting element 210 is mounted on the large chain link 152, the shifting element can pivot about the first camshaft 460 toward and away from the large chain link 152, as further described below. For accommodation, the teeth 288 of the chain guide pins 280 and the hooks 302 of the chain shifting pins 282 are also arranged in the same arc as the holes 264a to e. Therefore, the teeth 288 of the chain guide pins 280 can freely pass through and exit from and enter through the corresponding holes 264a to d in the large chain link 152. Similarly, the hooks 302 of the chain shifting pins 282 can freely pass through and exit from and enter through the hole 264e in the guard rail 206.

[0133] Referring to Figures 10 to 13, a torsion spring 466 can be used to bias the shifting element 210 in a desired direction. In this example, the torsion spring 466 is mounted on the first camshaft 460. The torsion spring 466 has a first leg 468, which is placed in a notch 470 on the bottom edge of the body 270 of the shifting element 210 and engages with the shifting element. The torsion spring 466 also has a second leg 472 abutting against the surface 226 of the large chain link 152. The legs 468 and 472 of the torsion spring 466 bias the shifting element 210 along the axis of the first camshaft 460 in a direction toward the large chain link 152, i.e., counterclockwise in Figure 13.

[0134] The gear motor unit 200 is placed in the motor recess 232 of the surface 226 of the large chain link 152. The hub 216 extending from the gear motor unit 200 is positioned above the pocket portion 234. One end of the first link 220a, i.e., the proximal end, is pivotally connected to the hub 216 by the first pin 222a, and the first pin 222a is received through a hole in the proximal end of the link and held by one of the retaining rings 224. The first link 220a extends along the first recessed channel 236a in the surface 226 of the large chain link 152. The upshift drive 340 is positioned above the upshifter recess 238 and the first camshaft 460 is received through a center hole 344 in the hub 342 of the upshift drive. A first drive pin 474a is received through a connecting hole 350 in the drive body 348 of the upshift drive 340 and through a hole at the other end, i.e., the distal end, of the first link 220a. The first drive pin 474a connects the first link 220a and the upshift drive 340 and is held by another fastener, such as a snap ring or retaining ring 476. In this way, the first link 220a is rotatably connected to the upshift drive 340. Referring to Figures 10 to 12 and 30, a retaining screw 478 is received in a screw hole 352 of the upshift drive 340. In this example, the inner end of the retaining screw 478 can engage a flat surface (not shown) on the first camshaft 460 to rotatably secure the upshift drive 340 to the first camshaft such that rotation of the upshift drive causes rotation of the first camshaft as described below.

[0135] Referring to Figures 10 to 12 and 38, the upshift actuator 360 is also positioned above the upshift recess 238. The first camshaft 460 is rotatably housed through a center hole 364 in the hub 362 of the upshift actuator 360. The drive arm 370 is positioned facing and within the upshift recess 238. The upshift actuator 360 is positioned adjacent to the upshift driver 340 on the first camshaft 460, with its faces 368 and 347 closely facing each other. The torque protrusion 366 of the upshift actuator 360 axially overlaps with the torque protrusion 346 on the upshift driver 340. Therefore, the torque protrusions 366 and 346 are rotatably engaged with each other. For example, a torsion spring, specifically an upshift spring 480, has an upshift biasing element disposed on the first camshaft 460 and axially between the upshift driver 340 and the upshift actuator 360. A first leg (not shown) of the upshift spring 480 contacts or engages a first elastic contact surface 354 on the upshift driver 340. A second leg 482 of the upshift spring 480 contacts or engages a second elastic contact surface 374 on the upshift actuator 360. The upshift spring 480 is disposed and configured to rotatably bias a torque protrusion 346 on the upshift driver 340 against a torque protrusion 366 on the upshift actuator 360, as shown in FIG38.

[0136] Referring to Figures 10 to 12, 32 and 39, the first downshift drive 380 is positioned above the first downshifter recess 244a, and the first camshaft 460 is also housed through a center hole 384 in the hub 382 of the first downshift drive. A retaining screw 486 is housed in a screw hole 392 on the first downshift drive 380. In this example, the inner end of the retaining screw 486 can engage another flat surface (not shown) on the first camshaft 460 to rotatably secure the first downshift drive 380 to the first camshaft such that rotation of the first camshaft also rotates the first downshift drive as further described below.

[0137] Referring to Figures 10 to 12 and 39, the first downshift cam 400 is also positioned above the first downshifter recess 244a. The first camshaft 460 is rotatably housed through a central bore 404 in the hub 402 of the first downshift cam. The cam arm 410 is positioned facing and within the first downshifter recess 244a. The first downshift cam 400 is positioned adjacent to the first downshift actuator 380 on the first camshaft 460, with its faces 408 and 388 closely facing each other. The torque protrusion 406 of the first downshift cam 400 axially overlaps with the torque protrusion 386 on the first downshift actuator 380. Therefore, the torque protrusions 406 and 386 are rotatably engaged with each other. For example, a torsion spring, specifically a first downshifting spring 490, has a first downshifting biasing element disposed on the first camshaft 460 and axially between the first downshifting driver 380 and the first downshifting cam 400. A first leg (not shown) of the first downshifting spring 490 contacts or engages a first elastic contact surface 394 on the first downshifting driver 380. A second leg 492 of the first downshifting spring 490 contacts or engages a second elastic contact surface 414 on the first downshifting cam 400. The first downshifting spring 490 is disposed and configured to rotatably bias a torque protrusion 386 on the first downshifting driver 380 against a torque protrusion 406 on the first downshifting cam 400, as shown in FIG39.

[0138] Referring to Figures 10 to 12, 14 to 16 and 39, the first downshifting element 212a is positioned above the first downshifting element recess 254a in the surface 226 of the large chain link 152. The fulcrum 322 of the first downshifting element 212a is received in the first downshifting element recess 254a. A first downshifting shaft 496a is received through the inner hole 258 of the supports 256 adjacent to the first downshifting element recess 254a. The first downshifting shaft 494a is axially held by a holding element, such as a snap ring or retainer 498a, at each end of the shaft. The first downshifting shaft 496a is also received through the holes 324 in the fulcrum 322 to pivotally support the first downshifting element 212a on the shaft and relative to the supports 256. For example, a torsion spring, specifically a first downshift biasing element of a first downshift spring 500a, can be disposed on the first downshift shaft 496a. A first leg (not shown) of the first downshift spring 500a can engage the surface 226 of the large chain link 152. A second leg 502 of the first downshift spring 500a can engage a spring contact surface 504 between the holes 324 at the fulcrum 322 on the first downshift element 212a. The first downshift spring 500a is assembled and configured to bias the head 334 and contact surface 338 of the first downshift element 212a in a direction away from the large chain link 152, i.e., counterclockwise in FIG. 39.

[0139] Referring to Figures 10 to 13 and 40, a second camshaft 506 extends between the equilateral support 250 adjacent to the second downshift recess 244b on the large chain link 152 (see Figures 14 and 15). The second camshaft 506 extends through the inner bore 252 of the equilateral support 250 (see Figures 14 and 16). At the end of the second camshaft 506, a pair of fasteners, such as a snap ring or a retaining ring 508 (see Figure 10), can be used to axially hold the shaft and prevent it from being pulled out of the inner bore 252 of the equilateral support 250.

[0140] Referring to Figures 10 to 13 and 34, one end of the second first link 220b, i.e., the proximal end, is pivotally connected to the hub 216 by the second pin 222b, and the second pin 222b is received through a hole in the proximal end of the second link and held by one of the retaining rings 224. The second link 220b extends along the second recessed channel 236b in the surface 226 of the large link 152. The second downshift drive 420 is positioned above the second downshifter recess 244b and the second camshaft 506 is rotatably received through the center hole 424 in the hub 422 of the second downshift drive. The other end of the second link 220b, i.e., the distal end, is received in the groove 436 of the protrusion 430 of the 420A. A second drive pin 474b is received through a connecting hole 432 in the protrusion 430 and through a hole at the distal end of the second link 220b. The second drive pin 474b rotatably connects the second link 220b and the second downshift actuator 420 and is held by another fastener, such as a snap ring or retainer (not shown). In this way, the second link 220b is rotatably connected to the second downshift actuator 420 and drives the second downshift actuator 420 to rotate.

[0141] Referring to Figures 10 to 13 and 40, the second downshift cam 440 is also positioned above the second downshifter recess 244b. The second camshaft 506 is rotatably housed through a center hole 444 in the hub 442 of the second downshift cam 440. The cam arm 450 is positioned facing and within the second downshifter recess 244b. The second downshift cam 440 is positioned adjacent to the second downshift driver 420 on the second camshaft 506, with its faces 448 and 428 closely facing each other. The torque protrusion 446 of the second downshift cam 440 axially overlaps with the torque protrusion 426 on the second downshift driver 420. Therefore, the torque protrusions 446 and 426 are rotatably engaged with each other. For example, a torsion spring, namely a second downshift spring 512, is provided with a second downshift biasing element on the second camshaft 506 and axially between the second downshift driver 420 and the second downshift cam 440. A first leg (not shown) of one of the second downshift springs 512 contacts or engages a first elastic contact surface 434 on the second downshift driver 420. A second leg 514 of one of the second downshift springs 512 contacts or engages a second elastic contact surface 454 on the second downshift cam 440. The second downshift spring 512 is provided and configured to rotatably bias a torque protrusion 426 on the second downshift driver 420 against a torque protrusion 446 on the second downshift cam 440, as shown in FIG40.

[0142] Referring to Figures 10 to 12, 14 to 16 and 40, the second downshifting element 212b is positioned above the second downshifting element recess 254b in the surface 226 of the large chain link 152. The fulcrum 322 of the second downshifting element 212b is received in the second downshifting element recess 254b. A second downshifting shaft 496b is received through the inner hole 262 of the supports 260 adjacent to the second downshifting element recess 254b. The second downshifting shaft 494b is axially held by a holding element, such as a snap ring or retainer 498b, at each end of the shaft. The second downshifting shaft 496b is also received through the holes 324 in the fulcrum 322 to pivotally support the second downshifting element 212b on the shaft and relative to the supports 260. For example, a torsion spring, specifically a second downshift biasing element of a second downshift spring 500b, can be disposed on the second downshift shaft 496b. A first leg (not shown) of the second downshift spring 500b can engage the surface 226 of the large chain link 152. A second leg 502 of the second downshift spring 500b can engage a spring contact surface 504 between the holes 324 at the fulcrum 322 on the second downshift element 212b. The second downshift spring 500b is assembled and configured to bias the head 334 and contact surface 338 of the second downshift element 212b in a direction away from the large chain link 152, i.e., counterclockwise in FIG. 40.

[0143] The configuration and construction of the components of the front derailleur system and the front derailleur unit 150 may differ from the examples shown and described herein. Specific components and their configurations may also differ. More specifically, for example, the shape, size, depth, height, width, length, and position of various features on the surface 226 of the large chain link 152, including various shaft supports, recesses, holes, and bores, may also differ. Certain features and / or components may be part of or carried by a portion of the small chain link 154 of the front derailleur unit 150. Furthermore, various physical details, such as the position, size, shape, structure, and material of various drives, actuators, cams, and upshifting and downshifting elements, may also differ from the examples described above. The types, sizes, positions, and configurations of various sub-components, including camshafts, pins, chain links, and biasing elements, may differ from the examples shown and described herein. Furthermore, the location, type, configuration, size, physical input and output characteristics, power consumption, and mechanical power output of the electromechanical and electronic components, including the gear motor and the control unit, may differ from the examples disclosed and described herein. Those skilled in the art will understand from this disclosure that the transmission system could function as required prior to this disclosure and description, but various modifications could be made to these component examples.

[0144] The operation of the front derailleur system will continue to be described below with reference to the following diagram and the above description of the components. The front derailleur system has two shifting states and two operating states. In this example, these operating states include a first operating state, namely a large chainring state, and a second operating state, namely a small chainring state. In the large chainring state, as shown in FIG2, the chain 138 is attached to the large chainring 152 and is still engaged with the sprocket teeth 160 on the large chainring, while the bicycle 100 is in a corresponding gear and a rider is pedaling the bicycle. In the small chainring state, as shown in FIG41, the chain 138 is attached to the small chainring 154 and is still engaged with the sprocket teeth 162 on the small chainring, while the bicycle 100 is in a corresponding gear and a rider is pedaling the bicycle. One, more, or all of the components of the front derailleur system may be in certain positions and configurations in the large chainring state and in different positions and configurations in the small chainring state. Alternatively, one or more or all of the components of the front derailleur system may be in the same position and configuration in each of the large and small chain link states. In these examples, the components of the front derailleur system may move from the large and / or small chain link states to different shifting states and configurations to allow the chain 138 to shift between the large and small chain links 152 and 154.

[0145] The front derailleur state includes a first state, namely an upshift state, and a second state, namely a downshift state. In the upshift state, the components of the front derailleur system and the front derailleur unit 150 are operated, positioned, or repositioned and configured to switch the chain 138 onto the large sprocket 152 and engage with the sprocket teeth 160 on the large sprocket. In the downshift state, the components of the front derailleur system and the front derailleur unit 150 are operated, positioned, or repositioned and configured to switch the chain 138 onto the small sprocket 154 and engage with the sprocket teeth 162 on the small sprocket. By operating the front derailleur system, the chain 138 can shift or switch between the large and small sprockets to change the gear ratio of the transmission system 124.

[0146] Please refer to Figures 2 to 6, 10, 11, 13 and 41 to 43, which show the upshifting state of the front derailleur unit 150 and describe the upshifting operation below. When the rider rides the bicycle 100 in the small chainring operation state, as shown in Figure 41, and the chain 138 is engaged with the small chainring 154, the rider can use the derailleur 128 to shift gears. The rider can press a button on the derailleur 128 to perform a gear shift or a gear change, thus switching the chain 138 from the small chainring 154 to the large chainring 152. This operation is defined herein as an upshift or an upshifting operation. Actuating the derailleur 128 causes a wireless signal to be transmitted from a radio transmitter or receiver of the derailleur to the front derailleur unit 150. More specifically, the wireless signal can be received by a radio transmitter or receiver on the PCB of the control unit 184. The wireless signal can be processed by the microprocessor on the PCB, and then a signal and power are transmitted to the gear motor unit 200.

[0147] The output section 214 and hub 216 are driven by the gear motor unit 200 to rotate counterclockwise as shown and reach the position shown in Figure 13. The counterclockwise rotation of the hub 216 in Figure 13 causes the first link 220a to move downwards and the second link 220b to move upwards, in other words, closer to the axis of rotation R. This movement of the first link 220a causes the upshift drive 340 to rotate counterclockwise to the position shown in Figure 13. This movement of the second link 220b causes the downshift drive 420 to rotate clockwise to the position shown in Figure 13.

[0148] When the upshift drive 340 is rotated counterclockwise to the position shown in Figures 13 and 38, the torque protrusion 346 of the upshift drive engages the torque protrusion 366 of the upshift actuator 360, causing the upshift actuator to rotate counterclockwise as shown in the figures. During this upshift operation, unlike the downshift operation described below, the upshift drive 340 directly drives the upshift actuator 360 to rotate without the assistance or intervention of the upshift spring 480. The upshift actuator 360 is then rotated to the position shown in Figures 13 and 38. In the position shown, the contact surface 372 on the drive arm 370 of the upshift actuator 360 avoids and separates from the body 270 of the upshift element 210, and therefore does not contact it. The gap between the contact surface 372 on the drive arm 370 and the body 270 of the shifting element 210 is sufficient to allow the shifting element to rotate counterclockwise toward the surface 226 of the large chain link 152. The biasing force applied to the body 270 of the shifting element 210 by the torsion spring 466 drives the shifting element to rotate around the axis of the first camshaft 460.

[0149] However, when the chain 138 on the small link 154 is not blocked by any of the holes 264a to 264d in the large link 152 and the hole 264e in the guard rail 206, as shown in FIG. 41, the shifting element 210 can only freely rotate completely to the position shown in FIG. 13 and 38. The transmission system 124 operates in the direction of arrow D, causing the front derailleur unit 150 to rotate about the axis R, as shown in FIG. 2 and 47. The holes 264a to 264e are partially blocked by the chain 138, blocking at least a portion of the rotation of the transmission system. As shown in FIG. 41, when the guard rail 206 and the shifting element 210 are positioned on the rear end or back end of the front derailleur unit 150 and between the upper (forward movement direction) and lower (backward return direction) segments of the chain, the holes 264a to 264e avoid the chain 138. Once the holes 264a to 264e avoid the chain 138, the torsion spring 466 biases the lifting element 210 to the position shown in Figures 13 and 38 adjacent to the surface 226 of the large chain link 152.

[0150] As the shifting element 210 rotates further counterclockwise toward the surface 226 of the large chain link 152, the chain guide pins 280 and the chain shifting pins 282 carried on the shifting element 210 move through the corresponding holes 264a to 264e and toward a plane S defined by the sprocket teeth 162 of the small chain link 154. The shifting element 210 rotates counterclockwise until the contact surface 276 in the plane C of the body 270 abuts against or contacts the surface 226 of the large chain link 152. The fully rotated shifting state of the shifting element 210 is shown in Figures 13 and 38.

[0151] As described above, both the upshift driver 340 and the first downshift driver 380 are fixed to the first camshaft 460 by fixing screws 478 and 486 and rotate together with it. Therefore, the upshift driver 340 rotates counterclockwise to rotate the first camshaft 460, and then the first downshift driver 380 rotates in the same direction. This direction is counterclockwise in Figures 13 and 38, but because the cross-section of the first downshift assembly in Figure 39 is viewed from the opposite direction to the cross-section of the assembly shown in Figures 13 and 38, it appears clockwise in this figure. When the first downshift driver 380 rotates clockwise in Figure 39, the torque protrusion 386 on the first downshift driver engages the torque protrusion 406 on the first downshift cam 400, and then the first downshift cam rotates clockwise to the position shown in Figure 39.

[0152] In this position, the first downshift cam 400 does not contact the first downshift element 212a. In the position shown, the cam surface 412 on the cam arm 410 of the first downshift cam 400 avoids and separates from, and therefore does not contact, the notch 330 on the cam surface 328 of the body 320 of the first downshift element 212a. The gap between the cam surface 412 on the cam arm 410 of the first downshift cam 400 and the cam surface 328 on the body 320 of the first downshift element 212a is sufficient to allow the first downshift element to rotate counterclockwise around the pivot axis P in FIG. 39. The first downshift element 212a rotates by the biasing force of the first downshift spring 500a. The first downshift spring 500a biases the first downshift element 212a in a counterclockwise direction as shown in FIG. 39, thereby moving the contact surface 338 on the head 334 of the first downshift element 212a away from the plane B defined by the sprocket teeth 160 of the large chain link 152. In this upshift state, as shown in FIG. 39, the head 334 of the first downshift element 212a does not overlap with the large chain link 152, that is, it does not intersect with the plane B. Furthermore, during the upshift operation, unlike the downshift operation described below, the first downshift driver 380 directly drives the first downshift cam 400 to rotate without the assistance or intervention of the first downshift spring 490.

[0153] Referring to Figures 2 to 6, 10, 11, 13, 40, and 41, the movement of the second downshifting element 212b and the components for an upshifting operation and the upshifting state is similar to the movement of the first downshifting element 212a. As described above, the motor output 214 and the hub 216 are driven by the gear motor unit 200 to rotate counterclockwise as shown and reach the position shown in Figure 13. The counterclockwise rotation of the hub 216 causes the second link 220b to move upward in Figure 13, in other words, closer to the axis of rotation R. This movement of the second link 220b causes the second downshifting driver 420 to rotate clockwise to the position shown in Figure 13. This direction is clockwise in both Figures 13 and 40. When the second downshift driver 420 rotates clockwise as shown in FIG40, the torque protrusion 426 on the second downshift driver engages the torque protrusion 446 on the second downshift cam 440, thereby causing the second downshift cam to rotate clockwise to the position shown in FIG40.

[0154] In this position, the second downshift cam 440 does not contact the second downshift element 212b. In the position shown, the cam surface 452 on the cam arm 450 of the second downshift cam 440 avoids and moves away from the notch 330 on the cam surface 328 of the body 320 of the second downshift element 212b. The gap between the cam surface 452 on the cam arm 450 of the second downshift cam 440 and the cam surface 328 on the body 320 of the second downshift element 212b is also sufficient to allow the second downshift element to rotate counterclockwise around the pivot axis P in FIG. 40. The second downshift element 212b rotates by the biasing force of the second downshift spring 500b. The second downshift spring 500b biases the second downshift element 212b in a counterclockwise direction as shown in FIG. 40, thereby causing the contact surface 338 on the head 334 of the second downshift element 212b to move away from the plane B of the large chain link 152. In this upshift state, as shown in FIG. 40, the head 334 on the second downshift element 212b also does not overlap or intersect with the plane B of the large chain link 152. Furthermore, during the upshift operation, unlike the downshift operation described below, the second downshift driver 420 directly drives the second downshift cam 440 to rotate without the assistance or intervention of the second downshift spring 512.

[0155] In Figures 2 to 6, 10, 11, 13, 38 to 43, the front derailleur system and the front derailleur unit 150 are shown in the upshift state as described above. However, the upshift operation has not yet occurred. The inclined contact surfaces 338 of the first and second downshift elements 212a and 212b are biased outward away from the plane B of the large chain link 152. Therefore, the downshift elements 212a and 212b are positioned so as not to interfere with the chain 138 when a rider operates the drivetrain 124 and when the chain is upshifted. Similarly, the chain guide pins and the chain upshift pins protrude through the holes 264a to 264e in the large chain link 152 and are positioned relatively close to the plane S of the small chain link 154 and ready to perform an upshift.

[0156] After the rider actuates the derailleur 128 to perform an upshift or shifting operation, as the rider continues to pedal, the chain 138 is released from the small chain link 154 and shifts up from the small chain link 154 to the large chain link 152, as shown in Figures 41 and 47 to 52 in sequence. Referring to Figure 41, the chain 138 is carried on the small chain link 154 and the rider pedals the derailleur 124 and the small chain link in the direction of arrow D. The chain guide pins 280 and the chain shifting pins 282 approach from below the chain 138, but have not yet reached the chain. Referring to Figure 47, one of the first or leading chain guide pins 280 protruding through the hole 264a of the large chain link 152 contacts the chain 138 and begins to engage the chain.

[0157] Figures 7 to 9 show various views of the chain 138, and Figure 53 shows the cross-section of the chain and the leading chain guide 280 when the hook 288 engages the chain. The sprocket teeth 162 on the chain 138 and the link 154 are timed or synchronized so that the tip of the hook 288 on the chain guide 280 rises into the tooth space 170 between the outer plates of one of the chain links. As the rider continues to pedal and the front derailleur 150 continues to rotate in the direction of arrow D, the chain links of the chain 138 are held by the hook 288 of the chain guide 280 at a position further away from the axis of rotation R of the front derailleur 150 than the positions of the chain links in front of the chain guide 280 and engaged with the link 154. The outer plate 168 of the chain link on the hook 288 slides downward from the position shown in Figure 53 along the inclined top surface 290 (or the hook is driven upward into the tooth space 170) to the position shown in Figure 54. Therefore, the chain 138 moves a relatively small distance away from the plane C of the small chain link 154 in a rightward or outward direction toward the plane B of the large chain link 152.

[0158] Figures 48 to 50 show that as the rider continues to pedal, the remaining portions of the chain guides 280 subsequently engage with the chain 138 in sequence. As described above, the chain guides 280 and the chain lifters 282 are positioned radially outward relative to the axis of rotation R of the front derailleur unit 150. Similarly, the teeth 288 and 302 of the chain guides 280 and the chain lifters 282 are each positioned axially away from the plane C of the link 154. As shown in Figure 48, the next subsequent chain guide 280, protruding through the hole 264b in the link 154, enters the tooth space 170 between the outer plates 168 of one of the subsequent or trailing links of the chain 138 and engages the outer plates. As the rider continues to pedal, the chain link 138 is held radially further away from the axis of rotation R by the next follower hook 288, relative to the position of the chain link engaging with the lead chain guide 280. Furthermore, the tip of the next follower hook 288 also enters the tooth space 170, as shown in FIG. 53. The outer plate 168 of the chain link on the hook 288 slides or moves downwards along the inclined top surface 290 from the position shown in FIG. 53 to the position shown in FIG. 54 relative to the tip of the hook. Therefore, the chain 138 moves to the right or outwards toward the plane B of the large link 152 and relative to the position of the chain on the lead chain guide 280, further away from the plane C of the small link 154 by a relatively small distance.

[0159] Referring to Figures 49 and 50, it is highlighted that the two subsequent chain guides 280 passing through the holes 264c and 264d each act in the same manner as the preceding chain guide 280 and the next subsequent chain guide. Thus, because the hooks 288 are positioned sequentially away from the axis, the chain 138 can be radially guided outward away from the axis of rotation R by the series of chain guides 280. Because the teeth are positioned sequentially close to the plane B, the chain 138 is also further guided outward toward the plane B of the large link 152 by the series of teeth 288 on the chain guides 280.

[0160] Referring to Figure 51, the chain lifter 282 then engages another trailing link of the chain 138. Referring to Figure 55, the tip of the hook 302 of the chain lifter 282 is positioned in the tooth space 170 between the outer plates 168 of one of the links. As the rider continues to pedal, the link of the chain 138 is held by the chain lifter at a position further outward radially away from the axis of rotation R compared to the previous link on the preceding adjacent chain guide 280. The link of the chain 138 also slides down along the chamfered top surface 304 of the hook 302 from the position shown in Figure 55 to the position shown in Figure 56. This moves the link of the chain 138 to align with the plane B of the chain link 152. The subsequent link of the chain 138 then engages with the sprocket teeth 160 on the chain link 152. As the rider continues to pedal and the front derailleur unit 150 continues to rotate around the axis of rotation R, the chain becomes fully engaged with the large chain link 152, as shown in Figures 2 and 52.

[0161] As described above, the sprocket teeth 160 on the large link 152 may include alternating narrow teeth 160n and wide teeth 160w that can respectively engage the narrow tooth spaces 166 between the inner plates 164 (i.e., narrow links) and the wide tooth spaces 170 between the outer links 168 (i.e., wide links). The small link 154 may also include such alternating narrow teeth 162n and wide teeth 162w. In this example, the chain guides 280 and chain lifters 282 are timed or synchronized and separated to engage the equal-width chain links, and the dimensions of the teeth 288 and 302 are configured to engage the equal-width tooth spaces 170. However, the dimensions of the chain guides, chain lifters, and each tooth may be configured and separated to engage with the alternating wide and narrow links and tooth spaces of the chain or only with the narrow links and tooth spaces of the chain.

[0162] The guard 206 can be configured to have a specific height for protruding outward by a required radial distance relative to the position of the sprocket teeth 160. The guard rail 206 can also be configured to have a specific length for covering an arc of a required angle of the large chain link 152. Similarly, the guard rail 206 can be positioned relative to the chain shifter 282 on the large chain link 152 and separated from the outer side of the large chain link by a required distance to prevent the chain 138 from moving outward when the chain shifts onto the large chain link. In other words, the size, shape, and position of the guard rail 206 can be made as needed to allow the chain 138 to engage the sprocket teeth 160 while preventing it from derailing to the outer side of the large chain link during shifting operations. As the rider continues pedaling and the chain 138 engages the chain link 152, as shown in Figures 2 and 52, the chain upshift pin 282 and hook 302 remain aligned with plane B of the chain link 152. Therefore, the hook 302 effectively acts as an axial guide, replacing or forming one of the sprocket teeth of the chain link 152. In this example, the front derailleur system and the components of the front derailleur unit 150 remain in an upshift position until the rider requests or downshifts.

[0163] Please refer to Figures 12 and 44 to 46 below to show the downshifting state of the front derailleur unit 150 and the downshifting operation is described below. When the rider is riding the bicycle 100 and the chain 138 is engaged with the large chainring 152 as shown in Figures 2 and 52, the rider wishes to change gears. This gear change requires a downshifting operation of the front derailleur unit 150 to switch the chain 138 from the large chainring 152 to the small chainring 154. The rider can press or operate the actuator of the derailleur 128 on the handlebar assembly 114. A wireless signal is then sent to the front derailleur unit 150 and received by a radio or wireless receiver or transceiver on the PCB of the control unit 184. The processor or microprocessor of the control unit 184 then processes the signal and transmits an appropriate signal and power to the gear motor unit 200.

[0164] During the downshift operation, the gear motor unit 200 is operated to drive or rotate the output section 214 in a clockwise direction, as shown in Figures 13 and 46. The clockwise operation of the gear motor unit 200 and the output section 214 causes the hub 216 to rotate clockwise from the position shown in Figure 13 to the position shown in Figure 46. The clockwise rotation of the hub 216 drives the first link 220a to move upward and the second link 220b to move downward to the position shown in Figure 46. The upward movement of the first link 220a causes the upshift driver 340 to rotate clockwise.

[0165] Referring to Figures 38 and 57, when the upshift drive 340 rotates clockwise, the biasing force of the upshift spring 480 causes the upshift actuator 360 to also rotate clockwise along with the upshift drive 340. This rotation keeps the torque protrusion 366 of the upshift actuator 360 firmly biased against and in contact with the torque protrusion 346 of the upshift drive 340. When the upshift actuator 360 rotates clockwise, the contact surface 372 of the upshift actuator 360 contacts and abuts against the inner side or surface of the body 270 of the upshift element 210. This rotation of the upshift actuator 360 thus biases or causes the upshift element 210 to also rotate clockwise away from the surface 226 of the large chain link 152. The rotation of the lifting element 210 in the clockwise direction of Figures 38 and 57 can thus move the chain guide pins 280 and the chain lifting pins 282 and their corresponding teeth 288 and 302 away from the plane S of the small chain link 154 and thus out of the holes 264a to 264e.

[0166] When the upshift element 210 is blocked from rotating clockwise away from the small chain link 154, the rider may attempt to downshift. This can occur when the chain 138 blocks the rotation of the upshift element 210. For example, when the chain is engaged on the large chain link 152 as shown in FIG. 2 but still with the hook 302 of the chain upshift pin 282 on the upshift element, the chain 138 can block the rotation of the upshift element 210. When this occurs, the upshift element 210 and the upshift actuator 360 can remain stationary while the upshift drive 340 continues to rotate. When this occurs, the torque protrusion 346 of the upshift drive 340 disengages from or moves away from the torque protrusion 366 of the upshift actuator 360. The upshift spring 480 thus winds up and stores energy. For example, when the crank assembly 132 rotates to a position where the hook 302 on the chain shifter 282 is separated from the chain 138, the shifter element 210 finally rotates freely in a clockwise direction. When the shifter element 210 rotates freely, the shifter element and the shifter actuator 360 rotate clockwise to the position shown in Figure 57 under the biasing force of the shifter spring 480.

[0167] When the shifting element 210 rotates clockwise, the chain guide pins 280 and chain shifting pins 282 move away from the plane S of the small chain link 154 and away from the holes 264a to 264e as described above. When the shifting element 210 is in the state shown in Figures 38 and 57, the direction or orientation of any force vector that can be transmitted through the first chain link 220a is substantially along the longitudinal axis of the first chain link through the rotation axis of the gear motor unit, i.e., the rotation center of the hub 216. In other words, if the shifting element 210 is subjected to an external force in the inward or counterclockwise direction (or even in the opposite direction), for example, if the shifting element is stuck by an object or accidentally bumped by the rider, the force will not cause the hub 216 or the gear motor unit 200 to be reverse-driven or rotated in the opposite direction. This is because any force vector is applied through the body 270 of the upshift element 210, through the upshift actuator 360 and the upshift driver 340, and through the first link 220a, and this is not intended to cause the hub 216 to rotate.

[0168] A fixing screw 314, which can be screwed through the body and passes along the lower edge of the body 270 of the shifting element 210, can be rotated or adjusted to fine-tune or adjust the position of the shifting element 210. The fixing screw 314 can be positioned on the body 270 of the shifting element 210 such that the contact surface 372 on the shifting actuator contacts the free end of the fixing screw protruding from the body, rather than the shifting actuator directly contacting the shifting element 210. Alternatively, the free end of the fixing screw 314 can be positioned to contact the surface 226 of the large chain link 152. In either case, the adjusted position of the fixing screw 314 can be used to determine the furthest inward rotation position of the shifting element 210 biased by the torsion spring 466 toward the surface 226 of the large chain link 152.

[0169] As described above, both the upshift driver 340 and the first downshift driver 380 are fixed to the first camshaft 460 by the aforementioned fixing screws 478 and 486. Rotation of the upshift driver 340 in the clockwise direction shown in Figures 38 and 57 also drives the rotation of the first camshaft 460, and thus the first downshift driver 380 rotates in the same clockwise direction. Referring to Figures 39 and 58, the first downshift element 212a is also shown from the opposite side compared to Figures 38 and 57. Therefore, the aforementioned clockwise rotation of the first downshift driver 380 in Figures 38 and 57 is shown in the opposite or counterclockwise direction in Figures 39 and 58. When the first downshift driver 380 rotates counterclockwise in Figures 39 and 58, the biasing force of the first downshift spring 490 drives the first downshift cam 400 to rotate counterclockwise together with the first downshift driver 380. The torque protrusion 406 of the first downshift cam 400 contacts and is firmly biased against the torque protrusion 386 of the first downshift driver 380. When the first downshift cam 400 rotates counterclockwise in Figure 58, the cam surface 412 on the cam arm 410 of the first downshift cam contacts the cam surface 328 on the drive arm 326 of the first downshift element 212a. This causes the first downshift element 212a to rotate clockwise around the first downshift shaft 496a in Figures 39 and 58. By this action, the first downshift element 212a rotates from the position shown in Figure 39 to the position shown in Figure 58.

[0170] Similar to the situation described above with upshift element 210, the first downshift element 212a cannot immediately rotate clockwise when attempting to downshift. For example, when the chain 138 is on the sprocket tooth 160 of the large chain link, if the first downshift element attempts to move toward the plane B of the large chain link 152, the chain 138 will block the movement of the first downshift element 212a. The head 334 on the body 320 of the first downshift element 212a will contact the side of the chain 138. If this occurs, the first downshift element 212a and the first downshift cam 400 remain stationary while the first downshift driver 380 continues to rotate driven by the rotation of the first camshaft 460. The torque protrusion 386 on the first downshift driver 380 rotates away and no longer contacts the torque protrusion 406 on the first downshift cam 400. Therefore, the first downshift spring 490 is wound and stores energy. As the crank assembly 132 continues to rotate, the first downshifting element 212a eventually becomes free to rotate toward the plane B of the large chain link 152. This occurs when the first downshifting element 212a is positioned behind the large chain link 152, at which point the chain 138 is not engaged with the sprocket teeth 160 on the large chain link. This position is shown in Figure 52, where the first downshifting element 212a rises upward toward the chain 138 but is adjacent to a rear portion of the large chain link 152 that is not engaged with the chain.

[0171] When the first downshifting element 212a rotates freely, the first downshifting cam 400 rotates counterclockwise in Figures 39 and 58 under the biasing force of the first downshifting spring 490. The rotation of the first downshifting cam 400 drives the first downshifting element 212a to rotate clockwise around the first downshifting shaft 496a in Figures 39 and 58. When the first downshifting element 212a rotates clockwise, the inclined contact surface 338 on the head 334 of the first downshifting element moves toward the plane B of the large chain link 152 until the head overlaps with the plane and the sprocket teeth 160, as shown in Figures 46 and 58. In this state, the first downshifting spring 500a biases the first downshifting element 212a away from the plane B of the large chain link 152 in the counterclockwise direction in Figure 58. Therefore, the first downshift spring 500a biases the cam surface 328 on the drive arm 326 of the first downshift element 212a against the curved cam surface 412 of the first downshift cam 400, thereby keeping the first downshift element 212a in a downshift state that overlaps with the plane B of the large chain link 152.

[0172] If the first downshifting element 212a is subjected to an external force that would cause it to move counterclockwise in FIG. 58, the first downshifting element remains stationary in this state. For example, when the first downshifting element 212a rises from below the chain 138 in FIG. 52 and contacts the chain, the force of the chain and the force of the first downshifting spring 500a will cause the first downshifting element to rotate counterclockwise around the first downshifting shaft 496a, thereby pushing the head 334 outward away from the plane B. However, because the drive arm 326 on the body 320 of the first downshifting element 212a abuts against and is blocked by the cam surface 412 of the first downshifting cam 400, the first downshifting element 212a cannot move counterclockwise in FIG. 58 in this downshifting state. In one example, the curve of the cam surface 412 may be cylindrical and concentric with the axis of the first camshaft 460. Therefore, any force vector applied by the cam surface 328 on the drive arm 326 of the first downshifting element 212a to the cam surface 412 of the first downshifting cam 400 in the downshifting state shown in FIG. 58 will pass through the axis of the first camshaft 460. Therefore, in this downshifting state, no external force applied by the chain 138 to the head 334 of the first downshifting element 212a will cause the first downshifting cam 400 to rotate around the first camshaft 460. Therefore, the force of the chain 38 will not cause the first downshifting cam 400 or the first downshifting element 212a to be reverse-driven or rotated away from the plane B of the large chain link 152.

[0173] At this time, the front derailleur system is in a downshift state, but a downshift has not yet been described or completed. Referring to Figures 46, 52, 57, and 58, the inclined contact surface 338 on the head 334 of the first downshifting element 212a is biased to overlap with the plane B of the large chain link 152. Similarly, the upshifting element 210, including the chain guide pins 280 and the chain upshift pins 282, is biased away from the plane S of the small chain link 154 in one direction. When the rider continues to pedal from the position of the previous derailleur unit in Figure 52, the chain 138 downshifts from the sprocket teeth 160 of the large chain link 152 to the small chain link 154, as shown in Figure 59. More specifically, when the first downshifting element 212a rises and contacts the chain 138, the inclined contact surface 338 on the first downshifting element prevents the chain from engaging the sprocket teeth 160 on the large chain link 152. Instead, the inclined contact surface 338 forces the chain 138 to redirect or deflect inward toward the plane S of the small chain link 154 and no longer align with the plane B of the large chain link. As the rider continues to pedal the front derailleur unit 150 in the direction of rotation R, the chain 138 continues to wind around and engage the sprocket teeth 162 of the small chain link 154, as shown in Figures 41 and 47. After the downshifting operation is completed, the front derailleur system remains in the downshifted state in this example until the rider requests or performs an upshift as described above.

[0174] In one example, the outer surface 226 of the large link 152 may include an elongated recess 520 relating to the position of each downshifting element, including in this example the first and second downshifting elements 212a and 212b. These recesses 520 may extend from the outermost radius of the large link 152, wherein the head 334 of each downshifting element is positioned adjacent to the sprocket teeth 160. The recesses 520 may extend in a gradually helical direction toward the sprocket teeth 162 of the small link 154. When the first downshifting element 212a in FIG. 59 downshifts to the sprocket teeth 162 on the small link 154, the recesses 520 may assist the chain 138 by providing sufficient clearance between the chain and the surface 226.

[0175] In the disclosed example, the front derailleur unit 150 has another, namely the second downshift element 212b, as described above, and not just the one or the first downshift element 212a detailed above. Referring again to Figures 12 and 44 to 46, the downshifting state of the front derailleur unit 150 is shown. During the downshifting operation described above, when the rider presses a button or operates the actuator of the derailleur 128 on the handlebar assembly 114, a wireless signal is sent to the front derailleur unit 150. This wireless signal can then be received by a radio or wireless transmitter or receiver on the PCB of the control unit 184. The processor or microprocessor of the control unit 184 then processes the signal and sends an appropriate signal and power to the gear motor unit 200. When the first downshift element 212a is actuated or moved to the downshifting state, the second downshift element 212b is also moved or actuated to the downshifting state.

[0176] Please refer to the combined front derailleur unit in Figures 10 to 12, the cross-sectional views in Figures 13 and 46, and the enlarged cross-sectional views in Figures 40 and 60. The following describes the movement of the second downshifting element 212b and the corresponding components during downshifting. During downshifting, the gear motor unit 200 drives or rotates the output section 214 and thus the hub 216 clockwise from the position shown in Figure 13 to the position shown in Figure 46. The clockwise rotation of the hub 216 drives the second chain link 220b downward from the position shown in Figure 13 to the position shown in Figure 46. The downward movement of the second chain link 220b causes the second downshifting driver 420 to rotate counterclockwise from the position shown in Figure 13 around the second camshaft 506 to the position shown in Figure 46.

[0177] When the second downshift driver 420 rotates counterclockwise in Figures 40 and 60, the biasing force of the second downshift spring 512 drives the second downshift cam 440 to rotate counterclockwise together with the second downshift driver 420. The torque protrusion 446 of the second downshift cam 440 contacts and is firmly biased against the torque protrusion 426 of the second downshift driver 420. When the second downshift cam 440 rotates counterclockwise in Figure 60, the cam surface 452 on the cam arm 450 of the second downshift cam contacts the cam surface 328 on the drive arm 326 of the second downshift element 212b. This causes the second downshift element 212b to rotate clockwise around the second downshift shaft 496b in Figures 40 and 60. The second downshift element 212b rotates from the position shown in Figure 40 to the position shown in Figure 60 by this action.

[0178] Similar to the situation described above for the first downshifting element 212a, the second downshifting element 212b cannot immediately rotate clockwise toward the plane B of the large chain link 152 when attempting to downshift. For example, when the chain 138 is on the sprocket tooth 160 of the large chain link, if the second downshifting element attempts to move toward the plane B of the large chain link 152, the chain 138 will block the movement of the second downshifting element 212b. The head 334 on the body 320 of the second downshifting element 212b will contact the side of the chain 138. If this occurs, the second downshifting element 212b and the second downshifting cam 440 remain stationary while the second downshifting drive 420 continues to rotate driven by the rotation of the hub 216 and the second chain link 220b. The torque protrusion 426 on the second downshift drive 420 rotates away from and no longer contacts the torque protrusion 446 on the second downshift cam 440. Therefore, the second downshift spring 512 winds up and stores energy. As the crank assembly 132 continues to rotate, the second downshift element 212b eventually becomes free to rotate toward the plane B of the large chain link 152. This also occurs when the second downshift element 212b is positioned behind the large chain link 152, at which point the chain 138 is not engaged with the sprocket teeth 160 on the large chain link. This position is not shown (but it should be similar to the position of the first downshift element 212a in Figure 52), but occurs when the second downshift element 212b rises upward toward the chain 138 but is adjacent to a rear portion of the large chain link 152 that is not engaged with the chain.

[0179] When the second downshifting element 212b rotates freely, the second downshifting cam 440 rotates counterclockwise in Figures 40 and 60 under the biasing force of the second downshifting spring 512. The rotation of the second downshifting cam 440 drives the second downshifting element 212b to rotate clockwise around the second downshifting shaft 496b in Figures 40 and 60. When the second downshifting element 212b rotates clockwise, the inclined contact surface 338 on the head 334 of the second downshifting element moves toward the plane B of the large chain link 152 until the head overlaps with the plane and the sprocket teeth 160, as shown in Figures 46 and 60. In this state, the second downshifting spring 500b biases the second downshifting element 212b away from the plane B of the large chain link 152 in the counterclockwise direction in Figure 60. Therefore, the second downshift spring 500b biases the cam surface 328 on the drive arm 326 of the second downshift element 212b against the curved cam surface 452 of the second downshift cam 440, thereby keeping the second downshift element 212b in a downshift state that overlaps with the plane B of the large chain link 152.

[0180] As with the first downshifting element 212a described above, if the second downshifting element 212b is subjected to an additional external force that would cause it to move counterclockwise in FIG. 60, the second downshifting element remains stationary in this state. For example, when the second downshifting element 212b rises from below the chain 138 (not shown) and contacts the chain, the force of the chain and the force of the second downshifting spring 500b will cause the second downshifting element to rotate counterclockwise around the second downshifting shaft 496b, thereby pushing the head 334 away from the plane B. However, because the drive arm 326 on the body 320 of the second downshifting element 212b abuts against and is blocked by the cam surface 452 of the second downshifting cam 440, the second downshifting element 212b cannot move counterclockwise in FIG. 60 in this downshifting state. In one example, the curve of the cam surface 452 can also be cylindrical and concentric with the axis of the second camshaft 506. Therefore, any force vector applied by the cam surface 328 on the drive arm 326 of the second downshift element 212b to the cam surface 452 of the second downshift cam 440 in the downshift state of FIG. 60 will pass through the axis of the second camshaft 506. Therefore, in this downshift state, no external force applied by the chain 138 to the head 334 of the second downshift element 212b will cause the second downshift cam 440 to rotate around the second camshaft 506. Therefore, the force of the chain 138 will not cause the second downshift cam 440 or the second downshift element 212b to be reverse-driven or rotated away from the plane B of the large chain link 152.

[0181] As with the first downshifting element 212a described above, the front derailleur system is in a downshifting state at this time, but a downshift has not yet been completed. Referring to Figures 46, 52 (for general reference) and 60, the inclined contact surface 338 on the head 334 of the second downshifting element 212b is biased to overlap with the plane B of the large chain link 152. The upshifting element 210, including the chain guide pins 280 and the chain upshift pins 282, is biased away from the plane S of the small chain link 154 in one direction. When the rider continues to pedal from one of the positions of the front derailleur unit 150 rotated 180 degrees from the position in Figure 52, the chain 138 downshifts from the sprocket teeth 160 of the large chain link 152 to the small chain link 154, as shown in Figure 59. More specifically, when the second downshifting element 212b rises and contacts the chain 138, the inclined contact surface 338 of the second downshifting element prevents the chain from engaging the sprocket teeth 160 on the large chain link 152. Instead, the inclined contact surface 338 forces the chain 138 to redirect or deflect inward toward the plane S of the small chain link 154 and no longer align with the plane B of the large chain link. As the rider continues to pedal the front derailleur unit 150 in the direction of rotation R, the chain 138 continues to wind around and engage the sprocket teeth 162 of the small chain link 154, as shown in Figures 41 and 47. After the downshifting operation is completed, the front derailleur system remains in the downshifted state in this example until the rider requests or performs an upshift as described above.

[0182] In the disclosed example, when an upshift is performed and after an upshift is performed, until the system moves to the next downshift position, the upshift element 210 is in an upshift state, rotated to a position adjacent to the large chain link 152. Simultaneously, the downshift elements 212a and 212b rotate to a position where they do not overlap with the sprocket teeth 160 of the large chain link 152. In this position, the downshift elements 212a and 212b are positioned not engaged with the chain 138. This downshift element position can be considered a neutral state, but the entire system is in an upshift state. Similarly, when a downshift is performed and after a downshift is performed, until the system moves to the next upshift position, the downshift elements 212a and 212b in the downshift state rotate to a position where they overlap with the sprocket teeth 160 of the large chain link 152. Simultaneously, the upshift element 210 rotates to a position away from the large chain link 152. In this position, the upshifting element 210 is positioned not engaged with the chain 138. This position can also be described as neutral, but the entire system is in a downshift position.

[0183] As described above, the front derailleur unit 150 in this example includes two downshifting elements 212a and 212b. These two downshifting elements are oriented approximately 180 degrees relative to each other on the large chainring 152. Therefore, these downshifting elements provide two opportunities to perform or engage a downshift each time the crank assembly 132 rotates. Thus, a downshift operation can be performed faster than if the front derailleur unit 150 had only one downshifting element. However, in another example, the front derailleur system may have only one downshifting element or may have two or more downshifting elements. In this example, the front derailleur unit 150 includes only one upshifting element 210 and the two downshifting elements 212a and 212b. In another example, the front derailleur unit may also include a second or more upshifting elements. Within the spirit and scope of this disclosure, the front derailleur system may include any number of upshifting elements and / or downshifting elements. Increasing the number of upshift and downshift elements can reduce the average time required to complete a shift when a shift is requested or performed by placing the next available shift element closer to the working side of the chain.

[0184] Referring to Figures 19 to 26, a rider may sometimes pedal the crank assembly backward relative to the rotation direction R. In the case of the rider pedaling backward and when the upshift element 210 is in the upshift state, the position and shape of the teeth 288 of the chain guides 280 and the position and shape of the hooks 302 on the chain upshift pins 282 can be assembled and configured to deflect or disengage the chain 138. More specifically, the inclined bottom surface 294 and the chamfered surfaces or chamfers 296a, 296b, and 296c on the teeth 288, and the inclined bottom surface 306 and the chamfered surfaces or chamfers 308a, 308b, and 308c on the hooks 302 are assembled such that the chain 138 is not engaged with the chain guides 280 or the chain upshift pins 282. These beveled surfaces and chamfers prevent chain derailment that could occur if the chain 138 engages the chain guides 280 or the chain shifter 282 while the rider pedals backward. The beveled bottom surface 294 and chamfers 296a, 296b and 296c on the teeth 288 and the beveled bottom surface 306 and chamfers 308a, 308b and 308c on the hook 302 can also be used to deflect or disengage the chain 138 after the shifter element 210 is biased or positioned in the shifted state, but before a shift operation occurs, when the chain guides 280 and the chain shifter 282 cross or rotate across the bottom or slack side of the chain.

[0185] In another example, referring to Figure 61, the front derailleur system may include an optional power meter 530 deployed and configured to measure the rider's electrical output when pedaling the bicycle 100. The power meter 530 is configured as part of a variable front derailleur unit 532. The power meter 530 may include strain gauges attached to the chain link structure material between a torque output and output segment to measure the electrical power transmitted through it. The power meter 530 may include a separate PCB including appropriate circuitry to determine and / or transmit signals representing those transmitted through the chain link structure. Power for operating the power meter 530 may be supplied via the power source 194 through a cable (not shown) extending from the power source to the power meter. In another embodiment, the power meter 530 and the front derailleur unit 532 may share a PCB within the control unit 184, instead of having a separate PCB for the power meter and the front derailleur unit. In this embodiment, the strain measuring device can still be attached to the chain link structure and assembled to measure the strain of the chain link structure.

[0186] In one example, the large sprocket 152 may have forty-eight (48) sprocket teeth 160 and the small sprocket 154 may have thirty-two (32) sprocket teeth 162. In this example, the number of sprocket teeth 160 on the large sprocket 152 and the number of sprocket teeth 162 on the small sprocket 154 are both multiples of four. This configuration allows the downshifting elements 212a and 212b to be positioned offset from or separated from each other by 180 degrees around the circumference of the front derailleur unit 150. Furthermore, the spatial relationship or timing between the relevant sprocket teeth 160 on the large sprocket 152 and the relevant sprocket teeth 162 on the small sprocket 154 may be the same for each position of the two downshifting elements. In this manner, the front derailleur unit 150 can be designed to provide a high-quality upshifting component geometry and a high-quality first downshifting component geometry for the rotational timing between the large and small chain links, while also ensuring that the second downshifting component geometry is identical to the first downshifting component geometry. Therefore, in the disclosed example, the number of teeth 160 on the large chain link 152 and the number of teeth 162 on the small chain link 154 are both multiples of four. However, the disclosed front derailleur system and front derailleur unit are not limited to this chain link design. Any number of teeth can be provided on these chain links.

[0187] As described above, the position of the upshift element 210 can be adjusted by operating the retaining screw 314. In the disclosed example, no device or mechanism for adjusting the position of the downshift elements 212a and 212b is disclosed. However, a device or mechanism associated with these elements and allowing adjustment may be included. For example, the downshift element 212a may be disposed in two components. One component may include the contact surface 338 on the head 334 and a second component may include the cam surface 328 and the drive arm 326. Both components can then be rotated independently about the first downshift shaft 496a. A retaining screw may be helically engaged with one of the two components and may have an exposed end that contacts the other component. The retaining screw may then be used to adjust the position of the contact surface 338 of the head 334 relative to the cam surface 328 on the drive arm 326. The specific construction of this adjustable downshift element is not further described here.

[0188] Referring to Figures 14, 15, 36, and 37, certain teeth 160 of the large chain link 152 and certain teeth 162 of the small chain link 154 may be configured to have a specific or different shape than the other teeth. For example, two teeth 160 of the large chain link 152 immediately preceding the positions of the downshifting elements 212a and 212b may have an outer surface 540 with material removed from the outer surface of the teeth. This tooth shape may be provided on these two specific teeth 160 to allow the chain 138 to deflect more easily inward during a downshifting operation. In another example, one specific tooth 160 of the large chain link 152 immediately preceding the positions of the chain upshifting pin 282 and the hole 264e may have an inner surface 542 with material removed from the inner surface of the teeth. The tooth shape allows the chain 138 to deflect or move slightly further outward during an upshift before engaging the hook 302 of the chain upshift bolt 282. In another example, a series of teeth 162 of the small link 154 is used to engage the first tooth of the chain 138 during a downshift. These teeth may have multiple specific chamfers 544 on their surfaces to optimize chain operation during a downshift. In yet another example, a series of teeth 160 of the large link 152 is used to engage the first tooth of the chain 138 after an upshift. These teeth may also have multiple specific chamfers 546 on their surfaces to optimize chain operation during an upshift.

[0189] In another example, the front derailleur system can be configured for so-called "synchronized shifting." In synchronized shifting, when a rider requests or executes an upshift or downshift, the front derailleur system automatically determines which front sprocket, i.e., the combination of the large sprocket 152 or the small sprocket 154, and which sprocket of the rear sprocket set 140 should engage the chain 138. The front derailleur system and the rear derailleur then switch the chain to the desired front sprocket and rear sprocket. The "synchronized shifting" system can be configured to sequentially shift from the highest gear to the lowest gear through each available gear combination, and vice versa.

[0190] In another example, the front derailleur system and the rear derailleur system can be configured for automatic shifting. In an automatic shifting system, the bicycle can be configured with multiple sensors that sense various drivetrain operating characteristics, and these sensors are used to automatically perform gear shifting. One or more of these sensed operating characteristics can be sensed and used to determine when the system should perform gear shifting. For example, these operating characteristics may include pedaling torque, pedaling pace, speed, and changes in these characteristics over a period of time. The front derailleur system and the rear derailleur system can be configured to automatically perform gear shifting on the bicycle without direct input from the rider when a predetermined combination of one or more of these characteristics is sensed or determined.

[0191] In another example, the front derailleur system and the rear derailleur system can be configured as a so-called half-step system. A half-step derailleur system is a known derailleur technique in which the gear ratio change between successive rear sprockets is almost twice the gear ratio change between the front sprockets. When the chain is shifted up or down on the sprockets of the rear sprocket assembly, the half-step system can shift the chain on the front sprocket assembly between the front sprockets at each shift and can shift the chain between the rear sprockets every other shift. In such a half-step system, very small sequential gear ratio changes can be produced.

[0192] The disclosed front derailleur system and front derailleur unit 150 are a two-stage system. The disclosed two-stage system has only two states: a downshift state and an upshift state. In the downshift state, the components or assemblies are configured to downshift the chain from a larger chain link to a smaller chain link and then maintain this state until an upshift operation is required. In the upshift state, the components or assemblies are configured to upshift the chain from a smaller chain link to a larger chain link and then maintain this state until a downshift operation is required. In another example, the front derailleur system and the front derailleur unit may be configured to have three states. The three states may include an upshift state for one of the upshift and downshift elements, a downshift state, and a different neutral state. The components or assemblies may be configured in the upshift state only when one of the chains is upshifted and may be configured in the downshift state only when one of the chains is downshifted. These components or assemblies can be configured to return to or be engaged in a neutral state when no upshift or downshift is being performed on the chain. In other words, the front derailleur system can be in the neutral state when the upshifting elements or the downshifting elements or both are respectively not engaged or configured to upshift or downshift the chain. The components or assemblies of the front derailleur system and the front derailleur unit 150 can therefore be configured to be in the neutral state when the rider is riding the bicycle and no gear shifting is being performed.

[0193] In another example, the gear motor unit 200 and the electronic control unit 184 may be housed or contained within the same housing or enclosure, rather than having multiple separate housings as in the aforementioned examples. The gear motor unit and the electronic control unit may be configured as a single controller providing the functions of both the gear motor unit and the electronic control unit.

[0194] In one example, the large link 152 and the small link 154 may be integrally formed as a single component or link assembly 228, as disclosed in the example. In another example, the large link and the small link may be separately formed components, which are then directly fixed to each other to form a link assembly that is indirectly engaged with each other through a third component, such as a link hub.

[0195] In one example, all the various shifting mechanisms, components, or assemblies of the front derailleur unit 150 are directly mounted on the chain link assembly. In the disclosed example, all the shifting mechanisms, components, or assemblies are ultimately formed as an integral part of the large chain link 152 or mounted on the large chain link 152. In another example, one, more, or all of the various shifting mechanisms, components, or assemblies may be formed as an integral part of the small chain link 154 or mounted on the small chain link 154. In yet another example, one, more, or all of the various shifting mechanisms, components, or assemblies of the front derailleur system and the front derailleur unit may be mounted on a different independent component (not shown) of the unit. This independent component may then be mounted on the front derailleur unit. For example, one, more, or all of the various shifting mechanisms, components, or assemblies may be mounted on the fairing of the front derailleur unit.

[0196] It is known in the field of bicycles that during a pedaling stroke, the torque input by a rider to the crank assembly 132 changes with the angular position of the crank arm 134. In the disclosed example, the crank arm 134 of the crank assembly 132 is angularly positioned relative to the upshift element 210 and the downshift elements 212a and 212b such that the pedaling torque input by the rider does not approach a maximum torque during an upshift or downshift operation. In another example, the crank arm 134 of the crank assembly 132 may be positioned at different angular positions relative to the upshift element 210 and the downshift elements 212a and 212b.

[0197] The above discloses specific materials used in certain shifting mechanisms, components, or assemblies. Prior to this disclosure, the shifting system and front derailleur unit 150 are not limited to these specific materials or to any specific material used in any mechanism, component, or assembly. Other suitable materials may certainly be used. In another example, the upshift element 210 may be formed from an injection-molded nylon material or a long-fiber reinforced thermoplastic material. In yet another example, the chain guide pins 280 and the chain upshift pins 282 may be inserted and molded into the body 270 of the upshift element 210. This avoids the need for individual adjustment of the position of each pin relative to the plane C of the contact surface 276 on the body 270. Other modifications may, of course, be made to the upshift element and to another shifting mechanism, component, or assembly among various shifting mechanisms, components, or assemblies.

[0198] In another example, the front derailleur unit 150 may be configured to include additional sensors, such as a three-axis gyroscope and / or a three-axis accelerometer. These components may be mounted on the PCB of the electronic control unit 184 or on another suitable component of the front derailleur unit. These additional sensors can be used to determine the angular position and / or angular velocity of the front derailleur unit 150 during pedaling. This position and velocity information can be used to improve the performance of the front derailleur system as described in more detail below. Other types of additional sensors may also be used as needed to obtain additional data and information.

[0199] In one example, the front and rear derailleur systems can be configured to prevent or prohibit gear shifting when a rider is not pedaling the bicycle 100 forward, or in other words, when the angular velocity of the front derailleur unit 150 in the direction of rotation R is not greater than zero. Alternatively, the front and rear derailleur systems can be configured to prevent or prohibit gear shifting when a rider is not pedaling the bicycle faster than a predetermined threshold, or in other words, when the angular velocity of the front derailleur unit 150 is not greater than the predetermined threshold. This feature can be added to help prevent a chain derailment or other unwanted system behavior.

[0200] In another example, the front and rear derailleur systems can be configured such that if a rider pedals backward during a shift, the shifting operation ends. If the rider pedals backward during a shift, the front and rear derailleur systems can return to their previous state before starting the shift, rather than continuing the shifting operation. This feature can also be added to help prevent a chain derailment or other unwanted system behavior.

[0201] In another example, the front and rear derailleur systems can be configured to delay shifting until the front derailleur unit 150 reaches a desired angular position. This feature can be achieved by using one or more sensors to obtain biaxial accelerometer data. The collected data can be used to determine the near-instantaneous angular position of the front derailleur unit 150 relative to the gravity vector. For example, one sensor of an accelerometer can be mounted on the bicycle frame 102 and used to determine the orientation of the bicycle 100 relative to the gravity vector. The orientation of the front derailleur unit 150 relative to the bicycle 100 can then be determined. Shifting of the front derailleur unit 150 can be delayed until the front derailleur unit reaches a desired angular position. If the error associated with it is small, the frame-mounted sensor can be omitted.

[0202] In another example, the front derailleur system can be configured to move the upshift element 210 and / or the downshift elements 212a and 212b to an intermediate position until a gear shift is completed. After the gear shift is completed, the upshift element 210 and the downshift elements 212a and 212b can be moved to a final stable position. In one example, this feature can be used to optimize the position of the upshift element 210 and / or the downshift elements 212a and 212b based on the position of the sprocket or tooth behind the rear sprocket set 140 that engages with the chain 138, i.e., based on the chain line or chain angle.

[0203] Figures 62 to 74 show an embodiment in which the power supply, PCB, motor, transmission mechanism, and related components are attached to and supported by a mechanism support bracket 661, rather than being directly attached to and supported by a chain link assembly 655. The power supply, PCB, motor, transmission mechanism, and related components, together with the mechanism support bracket 661, are included in a mechanism module 660, which is attached to the chain link in a manner that will be further described herein. A first advantage of this embodiment is that it allows the mechanism module and chain link assembly to be independently replaceable. For example, if the chain links are damaged, they can be easily replaced by the end user without replacing the mechanism module. A second advantage of this embodiment is that it simplifies and reduces the manufacturing costs associated with the chain link assembly. A third advantage of this embodiment is that the housing of the mechanism module covers the mechanism, protecting it from dirt and debris. A fourth advantage of this embodiment is that it improves aerodynamics without requiring a separate fairing.

[0204] Referring to Figures 62 and 63, the mechanism module 660 is attached to the front transmission unit 650 using a plurality of fasteners, such as five screws 662, which engage in corresponding screw holes in the front transmission unit 650. Other attachment techniques may also be used. For example, rivets or other fasteners may be used to attach the corresponding shapes of these components.

[0205] Figures 63 to 66 show the mechanism module 660, and Figures 67 to 69 show the mechanism support bracket 661 of the mechanism module 660. Referring to Figures 67 to 69, the mechanism support bracket 661 has a plurality of holes 672, five of which are configured to receive the aforementioned plurality of screws for attaching the mechanism module 660 to the front transmission unit 650.

[0206] Referring to Figures 67 and 69, shafts 630, 631, 632, and 633 are disposed in and supported by corresponding holes in the mechanism support bracket 661, and have the same function as shafts 460, 496a, 496b, and 506 in the aforementioned embodiment. Referring to Figure 65, the gear motor unit 200 is screwed onto the mechanism support bracket 661 using two screws 186 threaded into the mechanism support bracket 661. The first and second downshifting elements 612a and 612b are pivotally housed on and supported by the first and second downshifting pivots 631 and 633, respectively. The first and second downshifting element bias springs 623 and 624 are housed on and supported by the first and second downshifting pivots 631 and 633, respectively. The first legs of the bias springs 623 and 624 of the first and second downshifting elements respectively engage with the first and second downshifting elements 612a and 612b, and the second legs of the bias springs 623 and 624 respectively engage with the mechanism support bracket 661. The bias springs 623 and 624 of the first and second downshifting elements bias the first and second downshifting elements 612a and 612b in the same manner as in the aforementioned embodiment.

[0207] Referring to Figures 70 to 72, the shifting element 603 may be formed of long fiber reinforced thermoplastic ("LFRT"), glass-filled nylon, or other suitable materials such as certain metallic materials, and the plurality of chain guide elements 604 and chain shifting elements 605 may be formed of hardened steel or other materials operable to bear appropriate chain shifting and / or guiding loads and providing appropriate chain interaction and abrasion resistance properties. The plurality of chain guide elements 604 and chain shifting elements 605 are preferably inserted into the shifting element 603. Thus, the shifting element 603, chain guide elements 604, and chain shifting elements 605 can all function as a single piece. In other embodiments, these shifting elements and / or chain guide elements can operate independently. A plurality of stop surfaces 674 protrude from the shifting element 603 and, when the shifting element 603 is in the shifted position, stop the front derailleur unit 650, preventing further rotation of the shifting element 603.

[0208] Referring to Figure 65, the upshift element 603 is pivotally housed on and supported by the first camshaft 630. The upshift element bias spring 622 is also housed on and supported by the first camshaft 630. A first leg of the upshift element bias spring 622 engages the upshift element 603, and a second leg of the upshift element bias spring 622 engages the support bracket 661. The upshift element bias spring 622 biases the upshift element 603 in the same manner as in the aforementioned embodiment.

[0209] The remaining components associated with the mechanism (cams, drive elements, springs, chain links, hubs, etc.) may be supported and attached as described in the foregoing embodiments.

[0210] Referring to Figure 64, latch 196 is pivotally attached to a shaft, which is fixed to mechanism support bracket 661. A printed circuit board (or PCB, see Figure 63) 626 is housed within a waterproof chamber in mechanism support bracket 661. A button 676 on PCB 626 is accessible through a hole in mechanism support bracket 661, and an LED 192 on PCB 626 is visible through a transparent lens in mechanism support bracket 661. A conductive spring pin on PCB 626 protrudes from a hole in mechanism support bracket 661 and is electrically connected to a terminal of power supply 194, and these terminals can be attached to (and removed from) mechanism module 660 by operating latch 196. Multiple wires (not shown) transmit power and signals from PCB 626 to gear motor unit 200.

[0211] Referring to Figures 73 and 74, the front derailleur unit 650 has a plurality of holes 678, which may be the five screw holes described in this example, and these holes 678 receive the aforementioned fasteners (e.g., the five screws) that attach the mechanism module 660 to the front derailleur unit 650. Because the difficult-to-cut cross-drilling holes of other embodiments are omitted and replaced with screw holes 678 cut in the same direction as other morphologies in the front derailleur unit 650, the cutting of the front derailleur unit 650 is simplified compared to other embodiments. In addition, omitting the multiple protrusions that provide these cross-drilling holes results in a thinner all-over "blank," thereby significantly reducing the amount of material that must be removed during the cutting operation.

[0212] Referring to Figures 69 and 74, the mechanism support bracket 661 has two surfaces 680 and 682 that engage and abut against corresponding surfaces 684 and 621 in the front derailleur unit 650 to transmit the chain load from the chain to the front derailleur unit 650 as follows: During an upshift operation, the chain load is carried by the chain guide element 604 and the chain upshift element 605. The chain load is transmitted through the chain guide element 604 and the chain upshift element 605, through the upshift element 603, through the first camshaft 630, through the mechanism support bracket 661, and through the surfaces 680 and 682 of the mechanism support bracket 661 to the surfaces 684 and 621 of the front derailleur unit 650. In this way, the screw 662 is not required to carry the chain load during an upshift operation.

[0213] Figure 75 shows another embodiment in which the removable power supply 194 is omitted, and the non-removable power supply 663 is permanently installed within the mechanism module 660. The non-removable power supply 663 has the same function as the removable power supply 194 and preferably includes circuitry and structure for making the power supply 663 rechargeable. The non-removable power supply 663 is electrically connected to the PCB 626.

[0214] Figure 76 shows another embodiment, in which the removable power supply 194 is also omitted, and the power supply 664 is housed within a hollow space formed inside the spindle 665. The power supply 664 is preferably connected to the PCB 626 via a conductive cable and / or wire (not shown). The power supply 664 has the same function as the power supply 194 and is preferably rechargeable. The power supply 664 may be removable or permanently installed.

[0215] Figure 77 shows a power meter 530 incorporated into one of these embodiments. The power meter embodiment shown is known in the art and uses a stress meter attached to the front derailleur unit 650 to measure the rider's torque output. The power meter 530 may also include multiple sensors to measure the rider's pace. Using this torque and pace data, the power meter 530 calculates the rider's power output. The power meter 530 may receive power from the same batteries 194, 663, and / or 664 that power the derailleur, or the power meter may receive power from a separate power meter power supply 686, as shown in Figure 77. The power meter 530 may be covered by a waterproof cover (the cover is removed in Figure 77 for clearer view).

[0216] As previously described and as shown with reference to FIG5B, the exchange or speed change of a chain between two or more sprockets 152, 154 can be achieved by moving at least one ("1") speed change element 288 into one of the chain lines of a drive system. Speed ​​change elements 288, 302 are chain engagement elements such as bolts, hooks, or other elements as described herein. The speed change elements are configured to engage a link or plate of a chain. In the embodiment described, a single speed change element engages a single link or link plate. These speed change elements may be multiple protruding speed change elements, and these protruding speed change elements are axially movable relative to one of the rotation axes R of the sprockets. These protruding speed change elements may be configured to extend and / or retract axially to move into and / or out of the chain line and engage the chain. The at least one movable speed change element may be radially disposed between the root circle R3 of one of the larger sprockets and the tip circle R2 of one of the smaller sprockets. The at least one moving transmission element may include an array or a plurality of protruding transmission elements. In FIG5B, the plurality of protruding transmission elements 288 are shown as protruding transmission elements 288A, 288B, 288C, and 288D at different orientations on the chain link structure.

[0217] The protruding gear-changing elements 288A, 288B, 288C, 288D, and 302 of the array can be disposed at different radial distances D1, D2, D3, D4, and D5 relative to one of the rotation axes R of the structure. These distances can also be different relative to the larger and / or smaller sprockets. As shown, a first protruding gear-changing element 288A can be disposed between a tooth root circle R1 and a tooth tip circle R2 of the small chain link 154. A second protruding gear-changing element 302 can be disposed between the tooth root circle and a tooth tip circle R4 of the larger chain link 152. A plurality of protruding gear-changing elements 288B, 288C, and 288D can be disposed radially and / or circumferentially between the first protruding gear-changing element 288A and the second protruding gear-changing element 302. Each of the plurality of protruding gear-changing elements can have a tip that is configured to engage the chain. These tips are each positioned at different axial distances relative to the larger and smaller links 152 and 154.

[0218] These multiple protruding speed-changing elements enable the chain to change speed through a transition region T between the smaller chain link tooth and the larger chain link tooth. For example, the transition region can be defined as the radial region between the tooth tip circle R2 and the larger chain link tooth root circle R3. Multiple protruding speed-changing elements 288B, 288C, and 288D can be disposed in the transition region T.

[0219] A change in the exchange or switching between two or more sprockets from a large link 152 to a small link 154 can be achieved using a downshifting element, which can be configured to be movable into and / or out of the chain on the larger sprocket to allow the chain to slide or change speed toward the smaller sprocket on a sliding or tilting plane. Such downshifting elements can be located outside the transition region T, but allow the chain to move through the transition region T.

[0220] In the disclosed example, the front derailleur unit is generally described as including: the chain link unit, which includes the large and small chain links; and the front derailleur mechanism, which includes all various derailleur components. However, within the scope of this disclosure, more or fewer bicycle parts and components may be included or considered as part of the so-called front derailleur unit. Furthermore, the front derailleur system is generally described herein as including the front derailleur unit, the derailleur, the chain, and the crank assembly. Additionally, within the scope of this disclosure, more or fewer bicycle parts and components may be included or considered as part of the so-called front derailleur system. In the disclosed example, the drive wheel system is driven by the rear wheel, but this disclosure is not limited to this.

[0221] In one example, according to the teachings of this disclosure, a bicycle includes: a frame; a plurality of wheels for supporting the frame on a surface; a drivetrain operable to drive one of the drive wheels, the drivetrain including a sprocket assembly carried adjacent to the drive wheel and a chain coupled to the sprocket assembly. A front derailleur assembly is mounted on the bicycle and includes: a derailleur operable to transmit a wireless signal; and a crank assembly having two crank arms and a pedal connected to each of the two crank arms. The crank assembly is rotatable about a rotational axis. A front derailleur unit is coupled to the crank assembly to rotate together with it about the rotational axis. The front derailleur unit has a chain link assembly and a shifting mechanism coupled to the chain link assembly. The chain link assembly has a large chain link and a small chain link. The small chain link has a small diameter and the large chain link has a large diameter larger than the small diameter. The chain extends between the sprocket assembly and the chain link assembly. The transmission mechanism is configured such that the transmission receives the wireless signal and, based on the wireless signal, causes the chain to change speed between the large link and the small link.

[0222] In one example, the transmission mechanism can be on the large chain link.

[0223] In one example, the transmission mechanism may include at least one upshifting element that is movable relative to the front transmission unit to selectively engage the chain in order to perform an upshift of the chain from one of the smaller links to one of the larger links.

[0224] In one example, at least one upshifting element of the transmission mechanism may be mounted on the large chain link.

[0225] In one example, the transmission mechanism may include at least one downshifting element that is movable relative to the front transmission unit to selectively engage the chain in order to perform a downshift of the chain from one of the large links to one of the small links.

[0226] In one example, at least one downshifting element of the transmission mechanism may be mounted on the large chain link.

[0227] In one example, the transmission mechanism may include a first downshifting element and a second downshifting element. The second downshifting element may be positioned around one circumference of the chain link assembly opposite to or offset 180 degrees from the first downshifting element.

[0228] In one example, the transmission mechanism may include at least one downshifting element that is movable relative to the chain link assembly to selectively engage the chain in order to perform a downshift of the chain from one of the large chain link to one of the small chain links.

[0229] In one example of the teachings of this disclosure, a front derailleur unit for a bicycle includes a chain link assembly having a large chain link and a small chain link engaged for rotating together about a rotating axis. The large chain link has a large diameter and a plurality of large chain sprocket teeth, and the small chain link has a small diameter and a plurality of small chain sprocket teeth. The large diameter is larger than the small diameter. The front derailleur unit also includes a derailleur mechanism coupled to the chain link assembly. The derailleur mechanism includes an electronic control unit, a gear motor unit, at least one upshift element, at least one downshift element, and a power source. The power source is configured to provide power to the electronic control unit and the gear motor unit to operate the at least one upshift element and the at least one downshift element. According to a wireless upshift signal, the at least one upshift element can be operated by the electronic control unit and the gear motor unit to switch a chain from the plurality of small chain sprocket teeth on the small chain link to the plurality of large chain sprocket teeth on the large chain link. Based on a wireless downshift signal, the at least one downshifting element can be operated by the electronic control unit and the gear motor unit to switch a chain from the plurality of large ring sprocket teeth on the large chain link to the plurality of small ring sprocket teeth on the small chain link.

[0230] In one example, the link assembly may be formed from the same material as an integrated assembly.

[0231] In one example, the electronic control unit, the gear motor unit, the at least one upshifting element, the at least one downshifting element and the power supply may each be carried on the large chain link of the chain link assembly.

[0232] In one example, the electronic control unit, the gear motor unit, the at least one upshifting element, the at least one downshifting element and the power supply may each be carried on the outer surface of one of the large chain links.

[0233] In one example, the at least one downshifting element may include: a first downshifting element and a second downshifting element positioned around one circumference of the chain link assembly opposite the first downshifting element.

[0234] In one example, a first downshifting element and a second downshifting element of the transmission mechanism can be operated by a first link coupled to the gear motor unit.

[0235] In one example, the transmission mechanism may include a first camshaft coupled to the gear motor unit and rotatable about a first cam axis. An upshift driver is rotatable about the first cam axis and configured to move an upshift element of the transmission mechanism between an upshift state engaging one of the chain teeth on the small link sprockets and a neutral state not engaging one of the chain teeth on the link assembly. A first downshift driver is rotatable about the first cam axis and configured to move a first downshift element of the transmission mechanism between a downshift state engaging one of the chain teeth on the large link sprockets and a neutral state not engaging one of the chain teeth on the link assembly.

[0236] In one example, when one upshifting element of the transmission mechanism moves to an upshift state and engages a chain, one downshifting element of the transmission mechanism may be in a neutral state without engaging the chain. When the first downshifting element moves to a downshift state and engages the chain, the upshifting element may be in a neutral state without engaging the chain.

[0237] In one example, the transmission mechanism may include a second camshaft coupled to the gear motor unit and rotatable about a second cam axis. A second downshift drive rotatable about the second cam axis and configured to move a second downshift element of the transmission mechanism between a downshifted state that engages one of the chain teeth on the large chain links and a neutral state that does not engage one of the chain links on the chain link assembly.

[0238] In one example, when one upshifting element of the transmission mechanism moves to an upshift state and engages a chain, one first downshifting element and one second downshifting element of the transmission mechanism may be in a neutral state without engaging the chain. When the first and second downshifting elements move to a downshift state and engage the chain, the upshifting element may be in a neutral state without engaging the chain.

[0239] In one example, a first downshifting element and a second downshifting element of the transmission mechanism can move together between a downshifting state and a neutral state.

[0240] In one example, one of the second downshifting elements of the transmission mechanism can be operated by a second link coupled to the gear motor unit.

[0241] In one example of the teachings of this disclosure, a front derailleur system for a bicycle includes a derailleur that can be mounted on the bicycle. The derailleur is operable to transmit a wireless signal. The front derailleur system includes a crank assembly having two crank arms and a pedal connected to each of the two crank arms. The crank assembly is rotatable about a rotation axis. The front derailleur system includes a chain and a front derailleur unit coupled to the crank assembly and rotatable about the rotation axis. The front derailleur unit includes a chain link assembly having a large chain link and a small chain link. The small chain link has a small diameter and the large chain link has a large diameter larger than the small diameter. The front derailleur unit also includes a shifting mechanism coupled to the chain link assembly and rotatable together about the rotation axis. The shifting mechanism is configured to receive the wireless signal from the derailleur and, based on the wireless signal, shift the chain between the large chain link and the small chain link.

[0242] In one example, the gearbox may be mounted on a bicycle and located away from the front derailleur unit.

[0243] In one example, the transmission mechanism may include: an electronic control unit; a gear motor unit communicating with the electronic control unit; at least one upshifting element coupled to the gear motor unit; at least one downshifting element coupled to the gear motor unit; and a power supply configured to provide power to the electronic control unit and the gear motor unit to operate the at least one upshifting element and the at least one downshifting element.

[0244] In one example, based on a wireless upshift signal received by the electronic control unit, the at least one upshifting element can be operated by the gear motor unit to switch the chain from the small link to the large link. Based on a wireless downshift signal received by the electronic control unit, the at least one downshifting element can be operated by the gear motor unit to switch the chain from the large link to the small link.

[0245] In one example, the electronic control unit, the gear motor unit, the at least one upshifting element, the at least one downshifting element and the power supply may each be carried on the large chain link of the chain link assembly.

[0246] In one example, at least one downshifting element of the transmission mechanism may include a first downshifting element; and a second downshifting element, which may be positioned around a circumference of the chain link assembly opposite to the first downshifting element.

[0247] In one example, a first downshifting element and an upshifting element of the transmission mechanism can be operated by a first link coupled to the gear motor unit.

[0248] In one example, one of the second downshifting elements of the transmission mechanism can be operated by a second link coupled to the gear motor unit.

[0249] In one example, the transmission mechanism may include a first camshaft coupled to the gear motor unit and rotatable about a first cam axis. The transmission mechanism may also include an upshift driver rotatable about the first cam axis and configured to move an upshift element of the transmission mechanism between an upshift state engaging the chain on the small sprocket and a neutral state disengaging the chain on the sprocket assembly. The transmission mechanism may also include a first downshift driver rotatable about the first cam axis and configured to move a first downshift element of the transmission mechanism between a downshift state engaging the chain on the large sprocket and a neutral state disengaging the chain on the sprocket assembly.

[0250] In one example, when one of the upshifting elements of the transmission mechanism moves to an upshift state, a first downshifting element can be in a neutral state. When the first downshifting element moves to a downshift state, the upshifting element can be in the neutral state.

[0251] In one example, the transmission mechanism may include a second camshaft coupled to the gear motor unit and rotatable about a second cam axis. The transmission mechanism may also include a second downshift drive rotatable about the second cam axis and configured to move a second downshift element of the transmission mechanism between a downshift state engaging the chain on the large chain link and a neutral state not engaging the chain on the chain link assembly.

[0252] In one example, when one upshifting element of the transmission mechanism moves to an upshift state, one first downshifting element and one second downshifting element of the transmission mechanism can be in a neutral state. When the first and second downshifting elements move to a downshift state, the upshifting element can be in the neutral state.

[0253] In one example, the first and second downshifting elements of the transmission mechanism can move together between a downshifting state and a neutral state.

[0254] In one example, the link assembly may be formed as an integral structure including the large link and the small link.

[0255] In one example of the teachings of this disclosure, a method of mounting a front derailleur system on a bicycle includes mounting a derailleur to a portion of the bicycle. The derailleur is operable to transmit a wireless signal. A crank assembly rotatable about an axis of rotation is attached to a frame of the bicycle. The crank assembly has: two crank arms; a pedal connected to each crank arm of the two crank arms; and a front derailleur unit coupled to the crank assembly to rotate together with it about the axis of rotation. The front derailleur unit has a chain link assembly and a shifting mechanism carried by the chain link assembly. A chain connects the chain link assembly to a rear sprocket of the bicycle. The derailleur is paired with an electronic control unit of the shifting mechanism carried by the chain link assembly.

[0256] In another example, a bicycle front derailleur assembly is provided. The front derailleur assembly includes a front derailleur unit configured to couple with a crank assembly for rotation about a rotation axis therewith. The front derailleur unit has a chain link assembly and a shifting mechanism coupled to the chain link assembly. The chain link assembly has a large chain link and a small chain link. The large chain link has a plurality of teeth defining a plane of the large chain link, and the small chain link has a plurality of teeth defining a plane of the small chain link. The small chain link has a small diameter, and the large chain link has a large diameter larger than the small diameter. The shifting mechanism includes at least one protruding shifting element disposed in a transition region between the large chain link and the small chain link. The shifting mechanism is configured to allow axial movement of the at least one protruding shifting element between the plane of the large chain link and the plane of the small chain link. The shifting mechanism may include a plurality of protruding shifting elements disposed in the transition region. The plurality of protruding shifting elements may be multiple upshifting elements. The shifting mechanism may include an upshifting element configured to move axially and intersect the plane of the small chain link. The upshifting element, configured to move axially and intersect the plane of the small chain link, may be radially disposed between a tooth root circle and a tooth tip circle of the small chain link. The shifting mechanism may further include at least one downshifting element, which may be movable relative to the front shifting unit to selectively engage the chain to perform a downshift from the large chain link to the small chain link. The at least one downshifting element may include a first downshifting element and a second downshifting element. The second downshifting element may be positioned around a circumference of the chain link assembly opposite the first downshifting element. The front shifting unit may further include an electric motor rotatably fixed to the chain link assembly, the electric motor being configured to move the at least one protruding shifting element axially. The transmission mechanism may further include at least one downshifting element that is movable relative to the front transmission unit to selectively engage the chain in order to perform a downshift of the chain from the large link to the small link, and the electric motor assembly also causes the downshifting element to move.

[0257] In another example, a front derailleur unit for a bicycle is provided. The front derailleur unit includes a chain link assembly having a large chain link and a small chain link engaged for rotatable about a rotation axis. The large chain link has a large diameter and a plurality of large chain sprocket teeth, and the small chain link has a small diameter and a plurality of small chain sprocket teeth. The large diameter is larger than the small diameter. The front derailleur unit also includes a shifting mechanism coupled to the chain link assembly. The shifting mechanism includes an electronic control unit, a gear motor unit, at least one upshift element, at least one downshift element, and a power source configured to provide power to the electronic control unit and the gear motor unit to operate the at least one upshift element and the at least one downshift element. The at least one upshifting element is disposed in a transition region between the small sprocket teeth and the large sprocket teeth and can be axially moved by the electronic control unit and the gear motor unit to switch a chain from the small sprocket teeth on the small sprockets to the large sprocket teeth on the large sprockets. The at least one downshifting element can be operated by the electronic control unit and the gear motor unit to switch a chain from the large sprocket teeth on the large sprockets to the small sprocket teeth on the small sprockets. The chain link assembly can be formed as an integrated assembly from the same material. The at least one upshifting element may include a plurality of upshifting elements. The electronic control unit, the gear motor unit, the at least one upshifting element, the at least one downshifting element, and the power supply can each be carried on an outer surface of the large sprocket. The at least one downshifting element may include: a first downshifting element and a second downshifting element positioned around a circumference of the chain link assembly opposite to the first downshifting element. The first downshifting element and the first upshifting element can be operated by a first link coupled to the gear motor unit.

[0258] The transmission mechanism may further include: a first camshaft coupled to the gear motor unit and rotatable about a first cam axis; an upshift drive rotatable about the first cam axis and configured to move the upshift element between an upshift state engaging one of the chain teeth on the small ring sprockets of the small chain link and a neutral state not engaging one of the chain teeth on the chain link assembly; and a first downshift drive rotatable about the first cam axis and configured to move the first downshift element between a downshift state engaging one of the chain teeth on the large ring sprockets of the large chain link and a neutral state not engaging one of the chain teeth on the chain link assembly. The upshift element is movable to the upshift state, the first downshift element is in the neutral state, and wherein, when the first downshift element is moved to the downshift state, the upshift element is in the neutral state. The transmission mechanism may further include: a second camshaft coupled to the gear motor unit and rotatable about a second cam axis; and a second downshift drive rotatable about the second cam axis and configured to move the second downshift element between a downshift state that engages one of the chain teeth on the large chain link and a neutral state that does not engage one of the chain teeth on the chain link assembly. The at least one upshift element may include a plurality of upshift elements, and the plurality of upshift elements move together to achieve the upshift state.

[0259] From the above discussion, it will be understood that the present invention can be embodied in various forms, including but not limited to the following: Example 1: A bicycle front derailleur assembly comprising: a front derailleur unit configured to couple with a crank assembly for rotation about a rotation axis therewith, the front derailleur unit having a chain link assembly and a derailleur mechanism coupled to the chain link assembly, wherein the chain link assembly has: a large chain link having a plurality of teeth defining a plane of the large chain link; and a small chain link having a plurality of teeth defining a plane of the small chain link, the small chain link having a small diameter and the large chain link having a large diameter larger than the small diameter, and wherein the derailleur mechanism includes at least one protruding derailleur element disposed in a transition region between the large chain link and the small chain link, the derailleur mechanism being configured to allow the at least one protruding derailleur element to move axially between the plane of the large chain link and the plane of the small chain link. Example 2: As with the gearbox assembly preceding Example 1, the gearbox mechanism includes a plurality of protruding shift elements disposed in the transition region. Example 3: As with the gearbox assembly preceding Example 2, the plurality of protruding shift elements are multiple upshift elements. Example 4: As with the gearbox assembly preceding Example 3, the gearbox mechanism includes an upshift element configured to move axially and intersect the plane of the small chain link. Example 5: As with the gearbox assembly preceding Example 4, the upshift element configured to move axially and intersect the plane of the small chain link is radially disposed between a tooth root circle and a tooth tip circle of the small chain link. Example 6: As with the gearbox assembly preceding Example 3, the gearbox mechanism further includes at least one downshift element, which is movable relative to the front gearbox unit to selectively engage a chain to perform a downshift of the chain from the large chain link to the small chain link. Example 7: As with Example 6 and earlier gearbox assemblies, the at least one downshifting element includes a first downshifting element and a second downshifting element. Example 8: As with Example 7 and earlier gearbox assemblies, the second downshifting element is positioned around a circumference of the chain link assembly opposite the first downshifting element. Example 9: As with Example 7 and earlier gearbox assemblies, the front gearbox further includes an electric motor rotatably fixed to the chain link assembly, the electric motor being configured to move the at least one protruding gearbox element axially. Example 10: As with Example 9 and earlier gearbox assemblies, the gearbox further includes at least one downshifting element, the at least one downshifting element being movable relative to the front gearbox to selectively engage the chain to perform a downshift from the large chain link to the small chain link, and the electric motor being configured to also move the downshifting element.Example 11: A front derailleur unit for a bicycle, the front derailleur unit comprising: a chain link assembly having a large chain link and a small chain link engaged with each other for rotatable about a rotation axis, the large chain link having a large diameter and a plurality of large sprocket teeth and the small chain link having a small diameter and a plurality of small sprocket teeth, the large diameter being larger than the small diameter; and a derailleur mechanism coupled to the chain link assembly, the derailleur mechanism including an electronic control unit, a gear motor unit, at least one upshifting element, at least one downshifting element, and a power source configured to provide power to the electronic control unit and the gear motor unit to operate the at least one upshifting element and the at least one downshifting element. The at least one upshifting element is disposed in a transition region between the small sprocket teeth and the large sprocket teeth and can be axially moved by the electronic control unit and the gear motor unit to switch a chain from the plurality of small sprocket teeth on the small sprockets to the plurality of large sprocket teeth on the large sprockets. The at least one downshifting element can be operated by the electronic control unit and the gear motor unit to switch a chain from the plurality of large sprocket teeth on the large sprockets to the plurality of small sprocket teeth on the small sprockets. Example 12: As with the gear shifting unit before Example 11, the chain link assembly is formed from a single material into an integrated assembly. Example 13: As with the gear shifting unit before Example 11, the at least one upshifting element includes a plurality of upshifting elements. Example 14: As with the transmission unit prior to Example 11, the electronic control unit, the gear motor unit, the at least one upshifting element, the at least one downshifting element, and the power supply are each carried on an outer surface of one of the large chain links. Example 15: As with the transmission unit prior to Example 11, the at least one downshifting element includes: a first downshifting element; and a second downshifting element positioned around a circumference of the chain link assembly opposite the first downshifting element. Example 16: As with the transmission unit prior to Example 15, the first downshifting element and the upshifting element are operable via a first chain link coupled to the gear motor unit. Example 17: A transmission unit as described in Example 16, wherein the transmission mechanism further comprises: a first camshaft coupled to the gear motor unit and rotatable about a first cam axis; an upshift drive rotatable about the first cam axis and configured to move the upshift element between an upshift state engaging one of the chains on the small ring sprocket teeth of the small chain link and a neutral state not engaging one of the chains on the chain link assembly; and a first downshift drive rotatable about the first cam axis and configured to move the first downshift element between a downshift state engaging one of the chains on the large ring sprocket teeth of the large chain link and a neutral state not engaging one of the chains on the chain link assembly.Example 18: As with the transmission unit prior to Example 17, wherein when the upshift element moves to the upshift state, the first downshift element is in the neutral state, and wherein when the first downshift element moves to the downshift state, the upshift element is in the neutral state. Example 19: As with the transmission unit prior to Example 17, wherein the transmission mechanism further includes: a second camshaft coupled to the gear motor unit and rotatable about a second cam axis; and a second downshift driver rotatable about the second cam axis, and configured to move the second downshift element between a downshift state engaging one of the chains on the large chainring sprocket teeth of the large chainring and a neutral state not engaging one of the chains on the chainring assembly. Example 20: As with the transmission unit prior to Example 19, wherein the at least one upshift element includes a plurality of upshift elements and the plurality of upshift elements move together to achieve the upshift state.

[0260] Although certain examples of front derailleur systems, front derailleur units, derailleur mechanisms, their components and / or assemblies, and derailleur methods have been described herein based on the teachings of this disclosure, the scope of this patent is not limited thereto. Rather, this patent covers all embodiments of the teachings of this disclosure that fall entirely within the scope of possible equivalents.

[0261] The description of the embodiments herein is intended to provide a general understanding of the structure of various embodiments. These descriptions are not intended to be a complete description of all elements and features of the apparatus and systems using the structures or methods described herein. Many other embodiments will be apparent to those skilled in the art upon review of this disclosure. Numerous other embodiments can be used and derived from this disclosure, and structural and logical substitutions and changes can be made without departing from the scope of this disclosure. Furthermore, these illustrations are merely representative and may not be drawn to scale. Some scales in the illustrations may be enlarged, while others may be reduced. Therefore, this disclosure and these figures should be considered illustrative rather than limiting.

[0262] Although this specification contains numerous details, these details should not be construed as limiting the scope of the invention or the scope that may be claimed, but rather as specific descriptions of features of particular embodiments of the invention. Certain features described in the context of different embodiments in this specification may also be implemented in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately in multiple embodiments or in any suitable combination. Furthermore, although multiple features may function in certain combinations as described above or even be so requested from the outset, one or more features from a requested combination may be removed from that combination in some cases, and the requested combination may relate to a single combination or a variation thereof.

[0263] Similarly, although multiple operations and / or actions are shown in the figures and described herein in a specific order, this should not be construed as meaning that such operations must be performed in the specific order shown or in a sequential order, or that all shown operations must be performed to achieve the desired result. In some cases, multiplexing or parallel processing is advantageous. Furthermore, the separation of the various system components in the above embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that any of the said program components and systems may be integrated together in a single software product or packaged into multiple software products.

[0264] One or more embodiments disclosed herein may be referred to individually and / or collectively by the term "invention" for convenience only and without intentionally limiting the scope of this application to any particular invention or inventive concept. Furthermore, while specific embodiments have been shown and described herein, it should be understood that any subsequent configurations designed to achieve the same or similar purposes may replace the specific embodiments shown. This disclosure is intended to cover any or all subsequent modifications or variations of the various embodiments. Upon review of this description, those skilled in the art will understand combinations of the above embodiments and other embodiments not specifically described herein.

[0265] This abstract is provided so that it will not be used to interpret or limit the scope or meaning of the claims. Furthermore, in the foregoing detailed description, various features may be combined or described in a single embodiment to simplify the disclosure. This disclosure should not be construed as representing an invention that requires more features than specifically described in each claim. Rather, the following claims express that the subject matter of the invention may have fewer features than all of the disclosed embodiments. Therefore, the following claims are incorporated into this detailed description, and each claim independently defines the subject matter of its respective claim.

[0266] The foregoing detailed description is intended to be illustrative and not limiting, and it should be understood that the following claims, including all equivalents, are intended to define the scope of the invention. Unless otherwise stated, the claims should not be construed as limited to the order or elements described. Therefore, all embodiments within the scope and spirit of the following claims and their equivalents are claimed as part of the invention. [Simplified Explanation of the Diagram]

[0012] The purpose, features, and advantages of the present invention can be understood by reading the following description in conjunction with the accompanying drawings, wherein:

[0013] Figure 1 shows a side view of an example bicycle in a known road-ready state, the bicycle including a front derailleur system according to the teachings of this disclosure.

[0014] Figure 2 shows a right or outer plan view of a portion of the crank assembly of the bicycle in Figure 1 and includes a substantial portion of an example of a front derailleur system according to the teachings of this disclosure.

[0015] Figure 3 shows the crank assembly and front derailleur system of Figure 2, but the bicycle chain has been removed.

[0016] Figure 4 shows a right or outer perspective view of the crank assembly and front transmission system in Figure 3.

[0017] Figures 5 and 5B show the left or inner plan view of the crank assembly and front transmission system in Figure 3.

[0018] Figure 6 shows a rear view of the crank assembly and front transmission system of Figure 3.

[0019] Figure 7 shows a perspective view of one of the bicycle chain regulations shown in Figures 1 and 2, and the bicycle chain is applicable to the front derailleur system according to the teachings of this disclosure.

[0020] Figure 8 shows a top view of the bicycle chain in Figure 7.

[0021] Figure 9 shows a side view of the bicycle chain in Figure 7.

[0022] Figure 10 shows a right or outer plan view of one of the front transmission units of the transmission system in Figure 3 with a fairing and crank arm removed.

[0023] Figure 11 shows a right or outer perspective view of the front transmission unit example of Figure 10 and the transmission mechanism components in an upshift state according to the teachings of this disclosure.

[0024] Figure 12 shows the front transmission unit of Figure 11, but the transmission components are in a downshift state according to the teachings of this disclosure.

[0025] Figure 13 shows a cross-section taken along line 13-13 of the transmission unit in Figure 10 and the transmission mechanism components in the upshift state in Figure 11.

[0026] Figure 14 shows a right or outer perspective view of one of the chain link components of the transmission unit in Figure 10, with the transmission mechanism components removed.

[0027] Figure 15 shows a right or outer plan view of the chain link assembly in Figure 14.

[0028] Figure 16 shows a rear view of the chain link assembly in Figure 14.

[0029] Figure 17 shows a top view of an example of a shifting element for a shifting mechanism of the shifting unit prior to Figure 10, as taught in this disclosure.

[0030] Figure 18 shows a left or inside view of the upshifting element in Figure 17.

[0031] Figure 19 shows a perspective view of a chain guide bolt example of the lifting element of Figure 17 according to the teachings of this disclosure.

[0032] Figure 20 shows a top view of the chain guide pin of Figure 19.

[0033] Figure 21 shows a left or inside view of the chain guide pin of Figure 19.

[0034] Figure 22 shows a rear view of the chain guide pin of Figure 19.

[0035] Figure 23 shows a perspective view of a chain of shifting bolts of the shifting element of Figure 17 according to the teachings of this disclosure.

[0036] Figure 24 shows a top view of the chain shifter in Figure 23.

[0037] Figure 25 shows a left or inner view of the chain shifter in Figure 23.

[0038] Figure 26 shows a rear view of the chain shifter in Figure 23.

[0039] Figure 27 shows a perspective view of an example of a downshifting element for a transmission mechanism of the transmission unit preceding Figure 10, as taught in this disclosure.

[0040] Figure 28 shows a front view of the downshifting element in Figure 27.

[0041] Figure 29 shows a left or inside view of the downshifting element in Figure 27.

[0042] Figure 30 shows a perspective view of an example of an upshift drive for a transmission mechanism of the transmission unit preceding Figure 10, as taught in this disclosure.

[0043] Figure 31 shows a perspective view of an example of an upshift actuator for a transmission mechanism of the transmission unit preceding Figure 10, as taught in this disclosure.

[0044] Figure 32 shows a perspective view of an example of a first downshift drive for a transmission mechanism of the transmission unit preceding Figure 10, as taught in this disclosure.

[0045] Figure 33 shows a perspective view of an example of a first downshift cam for a transmission mechanism used in the transmission unit preceding Figure 10, according to the teachings of this disclosure.

[0046] Figure 34 shows a perspective view of an example of a second downshift drive for a transmission mechanism of the transmission unit preceding Figure 10, as taught in this disclosure.

[0047] Figure 35 is a perspective view of a second downshift cam example used in the transmission mechanism of the transmission unit preceding Figure 10, according to the present disclosure.

[0048] Figure 36 shows a perspective view of the left or inner side of the chain link assembly in Figure 14.

[0049] Figure 37 shows a left or inner plan view of the chain link assembly in Figure 14.

[0050] Figure 38 shows a cross-section taken along line 38-38 of the transmission unit in Figure 10 and shows the upshifting element of the transmission mechanism in the upshifting state.

[0051] Figure 39 shows a cross-section taken along line 39-39 of the transmission unit in Figure 10 and shows the first downshifting element in the upshifting state, that is, one of the first downshifting elements in the neutral state.

[0052] Figure 40 shows a cross-section taken along line 40-40 of the transmission unit in Figure 10 and shows the second downshifting element in the upshifting state, that is, one of the second downshifting elements in the neutral state.

[0053] Figure 41 shows a left or inside view of the transmission unit before Figures 10 and 11, but includes the chain, and is in the first stage of an upshift operation or before an upshift operation.

[0054] Figure 42 shows the left or inner view of the transmission unit before Figure 10 and in the upshift state.

[0055] Figure 43 shows a top view of the transmission unit preceding Figure 42.

[0056] Figure 44 shows the transmission unit before Figure 42, but in this downshift state.

[0057] Figure 45 shows the transmission unit before Figure 43, but in this downshift state.

[0058] Figure 46 shows the cross-section of the transmission unit in Figure 13, but the transmission mechanism components are in the downshift state.

[0059] Figures 47 to 49 show the gear shifting unit and chain as shown in Figure 41, but the chain guide pin of the upshifting element is further engaged with the chain in sequence and the chain is shifted by the small chain links of the chain link assembly.

[0060] Figure 50 shows the gear shifting unit and chain as shown in Figure 49, but the chain shifting bolt of the upshifting element engages the chain and the chain is further shifted by the small chain link.

[0061] Figure 51 shows the gearbox and chain before Figure 50, but the chain begins to engage the large link.

[0062] Figure 52 shows the gear shift unit and chain before Figure 51, but the chain has been completely switched to the large chain link.

[0063] Figure 53 shows a cross-section taken along line 53-53 of the guide bolt of the lead chain in Figure 47 before the chain is engaged.

[0064] Figure 54 shows the guide bolt of the chain in Figure 53, but the chain is fully engaged.

[0065] Figure 55 shows a cross-section taken along line 55-55 of the chain lifter in Figure 50 at the beginning of the engagement of the chain.

[0066] Figure 56 shows the chain lifter of Figure 55, but the chain is fully engaged.

[0067] Figure 57 shows the upshifting element of Figure 38, but in the downshifting state, that is, one of the upshifting elements is in neutral.

[0068] Figure 58 shows the first downshifting element of Figure 39, but in this downshifting state.

[0069] Figure 59 shows the gear shift unit and chain as shown in Figure 52, but the chain begins to switch from the large link to the small link.

[0070] Figure 60 shows the second downshifting element of Figure 40, but in this downshifting state.

[0071] Figure 61 shows a left or inner plan view of another crank assembly and front transmission system example according to the teachings of this disclosure.

[0072] Figures 62 to 74 and 78 show one embodiment of a front transmission system, which includes a mechanism support bracket and its components.

[0073] Figure 75 shows another embodiment of the transmission system preceding Figures 62 to 74.

[0074] Figure 76 shows another embodiment of the transmission system preceding Figures 62 to 74.

[0075] Figure 77 shows another embodiment of the transmission system preceding Figures 62 to 74.

Claims

1. A bicycle front derailleur assembly comprising: a front derailleur unit configured to couple with a crank assembly for rotation about a rotation axis therewith, the front derailleur unit having a chain link assembly and a derailleur mechanism coupled to the chain link assembly, wherein the chain link assembly has: a large chain link having a plurality of teeth defining a plane of the large chain link; and a small chain link having a plurality of teeth defining a plane of the small chain link, the small chain link having a small diameter and the large chain link having a large diameter larger than the small diameter, wherein the derailleur mechanism includes an upshifting element including at least one protruding derailleur element disposed in a transition region between the large chain link and the small chain link, the derailleur mechanism being configured to allow the at least one protruding derailleur element to move axially between the plane of the large chain link and the plane of the small chain link, and the derailleur mechanism also including at least one downshifting element movable relative to the front derailleur unit to selectively engage a chain to perform a downshift of the chain from the large chain link to the small chain link.

2. As requested in item 1, the transmission assembly, wherein the transmission mechanism includes: Multiple protruding transmission elements are arranged in this transition region.

3. As requested in item 2, the transmission assembly wherein the plurality of protruding transmission elements are multiple upshifting elements.

4. The transmission assembly as described in request item 3, wherein the transmission mechanism includes: A lifting element that is assembled to move axially and intersect the plane of the small chain link.

5. As requested in item 4 of the transmission assembly, wherein the upshifting element, which is configured to move axially and intersect the plane of the small chain link, is radially disposed between the root circle and the tip circle of one tooth of the small chain link.

6. The transmission assembly prior to request item 1, wherein the at least one downshifting element comprises a first downshifting element and a second downshifting element.

7. The transmission assembly prior to request item 6, wherein the second downshifting element is positioned around one of the circumferences of the chain link assembly opposite the first downshifting element.

8. The transmission assembly prior to claim 1, wherein the front transmission unit further comprises: an electric motor rotatably fixed to the chain link assembly, the electric motor being configured to move the at least one protruding transmission element axially.

9. The transmission assembly prior to claim 1, wherein the upshifting element and the at least one downshifting element are operated by a single electric motor of the front transmission unit, the single electric motor being configured to rotate together with the chain link assembly.

10. The transmission unit as described in claim 9, wherein the chain link assembly is formed as an integrated assembly from the same material.

11. The transmission unit prior to claim 1, wherein the at least one downshifting element and the upshifting element are operable by means of a first link coupled to a gear motor unit.

12. The transmission unit as described in claim 11, wherein the transmission mechanism further comprises: a first camshaft coupled to the gear motor unit and rotatable about a first cam axis; an upshift drive rotatable about the first cam axis and configured to move the upshift element between an upshift state engaging one of the chain teeth on the small ring sprockets of the small chain link and a neutral state not engaging one of the chain teeth on the chain link assembly; and a first downshift drive rotatable about the first cam axis and configured to move the first downshift element between a downshift state engaging one of the chain teeth on the large ring sprockets of the large chain link and a neutral state not engaging one of the chain teeth on the chain link assembly.

13. As requested in item 12, the transmission unit, wherein, When the upshifting element moves to the upshifting state, the first downshifting element is in the neutral state, and when the first downshifting element moves to the downshifting state, the upshifting element is in the neutral state.

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