Patent ID: 12208861

DETAILED DESCRIPTION OF THE DISCLOSURE

The present disclosure is related to front shifting systems for bicycles and to bicycles that incorporate such front shifting systems. The disclosed front shifting systems and bicycles solve or improve upon the above-noted and/or other problems and disadvantages with prior known front shifting systems and bicycles. The front shifting systems disclosed herein is incorporated entirely on the chain ring components, with no part separately attached to the bicycle frame. This provides frame designers with greater freedom of design, since the designers do not have to accommodate a portion of the front shifting system on the frame. The disclosed front shifting systems thus also eliminate the possibility of incorrectly positioning a portion of the front shifting system relative to the chain rings. The disclosed front shifting systems also improve shift performance because, since the bicycle frame is not a part of the front shifting system, any flex in the frame during use does not cause any problems while shifting. The disclosed front shifting systems can also be installed on bicycle frames that are not designed for mounting a front gear changer or derailleur. The disclosed front shifting systems shift smoothly and consistently, even while under heavy chain loads. The disclosed front shifting systems are easier to install and set up than a traditional front gear changer or derailleur and do not require specific skills or training. These and other objects, features, and advantages of the disclosed hub assemblies and trainers will become to those having ordinary skill in the art upon reading this disclosure.

Those having ordinary skill in the art should understand that the drawings and detailed description provided herein are for illustration only and do not limit the scope of the inventions or the disclosure. The appended claims define the scope of the inventions and the disclosure. The detailed description below may use terms such as “first”, “second”, “third”, “top”, “bottom”, “left”, “right”, “front”, “rear”, and/or the like. Use of such terms is only intended for clarity and often merely to differentiate among parts and components having the same names. Use of such terms is not intended to limit the scope of the disclosure to a specific order, arrangement, or orientation of such parts or components unless specifically stated herein. Further, such terms may refer to bicycle mechanisms that are conventionally mounted to a bicycle and with the bicycle oriented and used in a standard manner, unless otherwise indicated.

Also, multiple embodiments of the disclosed front shifting systems and bicycles may be disclosed and described herein. Each embodiment may have a specific combination of features, parts, components, functions, aspects, or the like. The scope of the disclosure is not intended to be limited solely to those specific combinations. Each of the disclosed features, parts, components, functions, aspects and the like may be employed independent of one another or in other combinations not specifically disclosed or described herein.

Exchanging, or shifting, a chain between two or more sprockets may be accomplished with at least one (“1”) shift element being moved into a chainline of a drive system. The shift elements may be protruding shift elements may move in an axial direction relative to a rotational axis of the sprockets. The protruding shift elements may be configured to extend and/or retract in the axial direction for moving into and/or out of the chainline. The at least one moving shift element may be disposed radially between a root circle of a larger sprocket and a tooth tip of a smaller sprocket. The at least one moving shift element may include an array or plurality of protruding shift elements. The protruding shift elements of the array may be disposed at different radial distances relative to the larger and/or smaller sprockets.

Exchanging, or shifting, a change between two or more sprockets may be accomplished from a larger sprocket to a smaller sprocket using downshifting element, which may be formed as a slide or slanted planar surface that may be moved into, and/or out of, the chainline at the larger sprocket to cause the chain to slide or shift towards the smaller sprocket.

A device for a cycle drive train may include movable shift elements. The movable shift elements may be disposed on a chain ring structure. The device for a cycle drive train may include movable down shift elements. The movable down shift elements may include a slanted surface configured to be moved into a chainline of a large chain ring. The device for a cycle drive train may include electronic and/or electrical elements configured to control and/or operate shift elements. The electronic and/or electrical elements may be disposed on a chain ring structure. The electronic and/or electrical elements may include an electric motor, electrical linear actuators, solenoids, or other electrical devices operable to cause motion or movement. In an example, the electric motor, or other electrical motive device, is configured to cause movement of the shift elements.

Turning now to the drawings,FIG.1depicts one example of a bicycle100with a frame102, a front wheel104coupled to a fork106of the frame, and a rear wheel108coupled to seat stays110and chain stays112on the frame. The wheels104,108support the frame102above a surface on which the bicycle100can travel in a forward direction indicated by the arrow ‘A’. The bicycle100has a handlebar assembly114that is mounted to a head tube116of the frame102. The bicycle100also has a seat118carried by a seat post120received in a seat tube122of the frame102.

The bicycle100has a multiple-geared drivetrain124that may have one or both of a front gear changer (described further below as a front shifting system) and a rear gear changer mounted to the frame102. The gear changers may be electromechanical derailleurs, for example, including a rear derailleur126and a front shifting system, which is described in detail below. The gear changers can be operable using a one or more gear shifters128, which may be mounted to the handlebar assembly114. The gear shifters128may operate the gear changes through wireless communication, as in the disclosed example, or via a physical connection using a mechanical shift cable or hydraulic line (not shown). The drivetrain124includes chain rings, also described in detail below, that are driven by a crank assembly132, which has two crank arms134and two pedals, respectively136. The chain rings are connected by a chain138to a plurality of sprockets on the frame102at the rear wheel108. The plurality of sprockets may be identified as a rear cassette140mounted to the frame102coaxial with the rear wheel108. The bicycle100as described above, other than the chain rings and the front shifting system, is known in the art and is shown inFIG.1to be a mountain bike. Those having ordinary skill in the art should recognize that the type and style of bicycle may vary from the disclosed example. For example, a road bicycle with drop-style handlebars, along with a drivetrain having road type gearing with a road gear range may be used instead of a mountain bike or other bicycle gear range.

In this example, the bicycle100includes brake system. The brake system includes at least one brake lever142that is movably connected to the handlebar assembly114. The brake lever142is configured to operate components of the braking system of the bicycle100. In one example, the brake system can include one or both of a hydraulic or cable actuated front brake mechanism144coupled to the front wheel104via a hydraulic line or mechanical cable146and a hydraulic or cable actuated rear brake mechanism (not shown) coupled to the rear wheel108through a hydraulic line or mechanical cable148. As noted above, the brake system can be a hydraulic actuated system or a mechanical actuated system and both are known in the art.

FIGS.2and3show substantial portions of a front shifting system of the drivetrain124of the bicycle100constructed in accordance with the teachings of the present disclosure and from the right side of the bicycle. The front shifting system includes a front shift unit150. The crank arms134of the crank assembly132are carried as part of the front shift unit150, around which the chain138is routed, as shown inFIG.2.FIG.3shows the same view of the front shifting system, but with the chain138removed. As described in detail below, the front shift unit150carries all the components of the disclosed front shifting system, other than the gear shifter128or wireless actuator. The wireless gear shifter128of the front shifting system is not carried on the front shift unit150since it needs to be in easy reach of a rider of the bicycle100. The gear shifter128may instead be mounted remotely on the handlebar assembly114of the bicycle100, as noted above.

FIGS.4-6show perspective, left side, and edge views of the portions of the front shifting system and front shift unit150depicted inFIGS.2and3. In this example, the front shift unit150has two chain rings152and154that are fixedly connected to and concentric with one another in order to rotate together about a rotation axis R of the front shift unit. The chain rings152,154are rotationally or torsionally engaged with one of the crank arms134through a mutual splined connection156. The crank arm134is retained to the front shift unit150by a plurality of screws158, which have threads configured to engage threaded holes (not shown) in the crank arm around the splined connection156. The screws158and splined connection156can vary from the example shown and can be replaced by other suitable fastener and connection configurations. The crank arm134may be torsionally engaged with, and retained to, a conventional spindle (not shown) in a manner that is well known in the art. The spindle can be rotatably received by ball bearings of a bottom bracket (not shown) carried on the frame102of the bicycle100. Thus, the front shift unit150may be rotatable relative to the bottom bracket about the rotation axis R.

FIGS.7-9depict several views of a small segment of the chain138. In a typical construction, the chain138can be formed of a plurality of inner and outer links that are joined together. The inner links are formed by pairs of inner plates164that define a narrower tooth space166between the plates. The outer links are formed by pairs of outer plates168that define a wider tooth space170between the plates. The plates164,168and links are joined to one another by rivets or pins172across the links and the width of the chain138. The rivets172can each optionally carry a roller174disposed between the plates and may include a bushing (not shown) between the rollers and rivets.

The chain138can engage either one of the chain rings152,154around their respective circumferences. The chain ring152has a relatively large diameter and may be called a big chain ring, as is known in the art. The big chain ring152has sprocket teeth160spaced apart around its perimeter or circumference. The chain ring154has a smaller diameter than the big chain ring152and may be called a small chain ring, as is known in the art. The small chain ring154has sprocket teeth162spaced apart around its perimeter or circumference. The chain138engages either the sprocket teeth160of the big chain ring152or the sprocket teeth162of the small chain ring154. The small chain ring154is positioned inboard or to the left of the big chain ring152in this example. The sprocket teeth160of the big chain ring152may be configured to have alternating narrow teeth160nand wide teeth160was can be seen inFIGS.4and6. Likewise, the sprocket teeth162of the small chain ring154may be configured to have alternating narrow teeth162nand wide teeth162w. Thus, the teeth160and162around the respective chain rings152,154may alternate between being narrow teeth160nor162nto fit the narrower tooth spaces166between the inner plates164and wide teeth160wor162wto substantially fill the wider tooth spaces170between the outer plates168of the chain138. By pedaling via the crank arms134in a rotational direction P, the front shift unit150and the chain138rotate, which drives a rear sprocket of the rear cassette140to propel the bicycle100forward in the direction of the arrow A inFIG.1.

Still referring toFIGS.2-6, a cover or cowling180is fixedly attached to the outboard or right facing side of the front shift unit150by screws182or other suitable fasteners or methods. The cowling180is sized to cover a substantial portion of the outboard side of the front shift unit150and shaped, i.e., smooth and rounded or domed, to reduce aerodynamic resistance to the bicycle's forward motion. The cowling180may be structural in nature (as opposed to being primarily an aerodynamic cover) to add strength and stiffness to the front shift unit150. Furthermore, the cowling180can be configured to keep road debris away from the more sensitive parts of the front shift unit150and to prevent the rider from accidentally coming into contact with these sensitive parts.

The main components of the front shifting system on the front shift unit150are first introduced below. More specific details of each of the main components, various additional sub-components, and ancillary components according to the teachings of the present disclosure are then described below. The function and operation of each of the main components, sub-components, and ancillary components are then described. Lastly, the shifting function and operation of the front shifting system are also described below. In general, the front shifting system includes components configured and arranged to shift the chain138between the big chain ring152and the small chain ring154according to a rider's selective operation of the shifter128. The disclosed front shifting system can upshift the chain138from the small chain ring154to the big chain ring152and can downshift the chain from the big chain ring to the small chain ring. Upshifts and downshifts are performed smoothly and quickly by the disclosed front shifting system and are performed with components that are disposed entirely on the front shift unit150.

First, referring toFIGS.3and10-12, the front shifting system includes a control unit184, which may be a waterproof electronic device. The control unit184is attached to the front shift unit150by screws or other fasteners186. In this example, the control unit184is attached to the outboard or right side of the big chain ring152. The control unit184contains a printed circuit board (PCB). The printed circuit board may include a wireless radio and antenna, a microprocessor, and spring-biased electrical contacts. During use, the wireless radio and antenna can send and receive shift commands to and from a rider-controlled actuator, such as the aforementioned shifter128, which may be located on the handlebar assembly114of the bicycle100. The wireless radio and antenna may also be used to communicate with the electronic rear derailleur126. The microprocessor can receive, process, and send out electronic signals. The microprocessor, wireless radio, and antenna can be contained within a waterproof housing or case188of the control unit184.

The control unit184may also have a button190and a light emitting diode (LED)192or other illumination element that are exposed on the housing188. The button190can be an electronic switch that is actuated by the rider. The button190may be used for pairing the control unit184of the front shift unit150with the shifter128on the handlebar assembly114and, optionally, for pairing the control unit184and thus the front shift unit150with the electronic rear derailleur126. The LED192may be a multi-color LED, such as a red-green-blue (RGB) LED or a red-green-blue-white (RGBW) LED. The LED may thus be capable of producing light in three colors and be configured to provide visual feedback to the rider to indicate a state of the front shifting system. Optionally, the printed circuit board may also include an electronic audio or noise emitter that can provide audible feedback to the rider.

Referring toFIGS.10-12, the front shifting system includes a power supply, which may be a rechargeable power supply194as described herein, for providing power to operate the front shifting system. In this example, the power supply194is attached to the housing188of the control unit184. A latch196may be provided and actuated so that the power supply194can be quickly and easily installed, removed, and replaced by a rider without the use of a tool. The power supply194may be a lithium-ion type rechargeable power supply or may be another suitable power supply type, if desired. When the power supply194is attached to the housing188of the control unit184, the power supply is in electrical contact with the spring-biased electrical contacts and can supply electrical energy to the PCB.

With continued reference toFIGS.10-12, the front shifting system also includes a gearmotor unit200, which may be a waterproof electromechanical device. In this example, the gearmotor unit200is mounted to the right or outboard side of the big chain ring152. The gearmotor unit200may be attached via screws202or other suitable fasteners to a bracket204carried on the outboard side of the big chain ring152. The bracket204may likewise be attached or mounted to the big chain ring152by similar fasteners or screws. Alternatively, the bracket204may be formed as an integral portion of the big chain ring152or as an integral portion of a housing of the gearmotor unit200to reduce the number of parts to be assembled from three to two. The gearmotor unit200can 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., output torque produced by the electric motor of the gearmotor unit200. The gear train can be internal to the gearmotor unit200and can be connected to and drive rotation of a mechanical output portion of the gearmotor unit200. The gearmotor unit200can also include an angular position sensing system (not shown) that senses the angular position of the mechanical output portion of gearmotor unit200. The gearmotor unit200receives electric power and electronic signals from the control unit184and can do so via an electric cable (not shown).

The front shifting system also includes a chain guard or guard rail206that is attached to the big chain ring152on the right side or outboard side. The chain guard rail206may be attached to the big chain ring152by screws208or other suitable fasteners. The chain guard rail206is sized and positioned to guide the chain138, as necessary during use and while shifting, in order to help prevent the chain138from derailing to the outboard side of big chain ring152. The chain guard rail206is placed adjacent the sprocket teeth160and spaced therefrom to the outboard side. The chain guard rail206acts as an outboard direction barrier for the chain138.

The front shifting system further includes an upshift element210that is carried on the big chain ring152. In this example, the upshift element210is on the right side or outboard side of the big chain ring152and is pivotable about its lower edge relative to the outboard side. In one example, the upshift element210can be made from aluminum so that the element is lightweight and yet strong and durable. The upshift element210may be cast aluminum in one example. The upshift element210is configured to selectively guide the chain138from the sprocket teeth162of the small chain ring154to the sprocket teeth160of the big chain ring152, as described in further detail below. In an alternate example, the upshift element210may be injection molded from a Nylon material or a long fiber reinforced thermoplastic material. Various components of the upshift element210, as described below, may also be attached separately to the upshift element210or may instead be molded or otherwise formed as an integral portion of the element.

The front shifting system also includes at least one downshift element carried on the right side or outboard side of the big chain ring152. In this example, the front shifting system includes two such elements including a first downshift element212aand a second downshift element212b, each being pivotable about a central portion thereof relative to the outboard side. In one example, the first and second downshift elements212aand212bare disposed generally 180 degrees opposite one another around the circumference of the front shift unit150. In one example, each downshift element212aand212bcan also be made from aluminum so that each element is lightweight and yet strong and durable. The first and second downshift elements212aand212bmay be cast aluminum in one example. As with the upshift element210, each downshift element212aand212b, in an alternate example, may be injection molded from a Nylon material or a long fiber reinforced thermoplastic material.

In the disclosed example, the first downshift element212aand second downshift element212bhave the same construction and configuration. Thus, only one downshift element may be shown or described in detail below. However, it should be understood that such illustrations and description may apply equally to either of the first and second downshift elements212aand212b. The first and second downshift elements212aand212bare generally configured to selectively guide the chain138from the sprocket teeth160of the big chain ring152to the sprocket teeth162of the small chain ring154, as described in further detail below. As will become apparent below, the front shifting system may include only one of the downshift elements or may include more than two of the downshift elements, if desired.

Referring now toFIGS.10,11, and13, in this example, output torque from the electric motor of the gearmotor unit200is transferred to the mechanical output portion of the gear motor unit. The mechanical output portion of the gearmotor unit200is identified herein generally as a motor output214, which can be in the form of an output shaft or a disc, bracket, horn, or the like coupled to such an output shaft via a splined interface or other suitable connection. The motor output214in this example may be axially retained to the gearmotor unit200by a screw or other suitable fastener (not shown). A hub216may be attached to the motor output214, also by screws218or other suitable fasteners. The hub216can be a circular disc or other suitable device for connecting the gearmotor unit200to other components of the front shifting system. In this example, the hub has a circumferential slot217formed around the perimeter of the hub. A first link220aand a second link220bare connected to the hub216. Each link220aand220bis a relatively thin, elongate element with a hole at each end. The hub216also has two holes formed through the hub and may be disposed 180 degrees opposite one another around the circumference of the hub. The proximal ends of the first link220aand second link220bare received in the slot217with their holes aligned with a corresponding one of the two holes in the hub216. A first pin222aand a second pin222bare substantially cylindrical in shape and are received through the corresponding holes in the hub216and in the proximal ends of the respective links220aand220b. The pins222aand222bare retained axially by retaining rings224to secure the proximal ends of the links220aand220bto the hub216. In this way, the first link220ais rotatably attached to the hub216via the first pin222aand the second link220bis rotatably attached to the hub216via the second pin222b. Rotation of the hub via the gearmotor unit200moves the first and second links222aand222bas described further below.

FIGS.14-16show perspective and plan views of what is defined herein as a chain ring component228, which includes the big chain ring152and the small chain ring154. As shown, the right side or outboard side of the big chain ring152with the components of the front shifting system removed. In this example, the outboard side of the big chain ring152has a surface226with numerous optional features provided thereon. These optional features may each be integrally formed by a machining, casting, or other suitable process as an integrated part of the surface226of the big chain ring152. Alternatively, a number of these optional features may be formed as separate components and attached to the surface226of the big chain ring152by welding, rivets, screws, or other suitable fasteners, or attachment techniques. In one example, the surface226may include a shallow recessed landing230that is sized and configured to receive the housing188of the control unit184therein. The landing230can assist in providing an easily identifiable mounting location for properly positioning the control unit184when installed on the surface226. In another example, the surface226may include a shallow motor recess232that is sized and configured to receive the gearmotor unit200therein. The brackets204, as noted above, may be integrally formed as a part of the surface226or may be separately attached thereto adjacent the motor recess232.

Further, a shallow pocket234may be formed having a semi-circular shape to provide clearance depth in the surface226for the hub216. The pocket234may be formed adjacent the brackets204but on the opposite side of the brackets relative to the motor recess232. Recessed first and second channels236aand236bmay be formed extending in opposite directions from the pocket234to accommodate the respective first and second links220aand220b(see alsoFIG.13). The surface226also include an upshifter recess238formed having a semi-circular shape to accommodate upshift driver and actuator components, as described below. A shaft support240is positioned adjacent to the upshifter recess238and includes a bore242that extends through the support for receiving a shaft, also as described below. The surface226further includes a first downshifter recess244a, also formed having a semi-circular shape, to accommodate a first downshift driver component, as described below. A shaft support246is positioned adjacent to the first downshifter recess244aand includes a bore248that extends through the support for receiving a shaft, also as described below. The upshifter recess238and the first downshifter recess244aare positioned spaced laterally apart on the surface226. The shaft supports240and246are positioned so that their respective bores242and248are concentrically aligned with one another. Further, the upshifter recess238is connected to the first channel236aso that the first link220acan extend from the hub pocket234to the upshifter recess238along the first channel.

The outboard side surface226of the big chain ring152further includes a second downshifter recess244b, also formed having a semi-circular shape, to accommodate a second downshift driver component, as described below. A pair of spaced apart shaft supports250is positioned adjacent to and on opposite sides of the second downshifter recess244b. Each of the shaft supports250includes a bore252that extends through the support for receiving a shaft, also as described below. The shaft supports250are positioned across the second downshifter recess244bfrom one another such that the bores252are concentrically aligned with one another. Further, the second downshifter recess244bis connected to the second channel236bso that the second link220bcan extend from the hub pocket234to the second downshifter recess244balong the second channel.

The surface226also includes a first downshift element depression254athat is positioned above and spaced from the first downshifter recess244a. The first downshift element depression254ais shaped and configured to accommodate the first downshift element212a, as described below. A pair of spaced apart shaft supports256is positioned adjacent to and on opposite sides of the first downshift element depression254a. Each of the shaft supports256includes a bore258that extends through the support for receiving a shaft, also as described below. The shaft supports256are positioned across the first downshift element depression254afrom one another such that the bores256are concentrically aligned with one another. The surface226further includes a second downshift element depression254bthat is positioned below and spaced from the second downshifter recess244b. The second downshift element depression254bis shaped and configured to accommodate the second downshift element212b, as described below. A pair of spaced apart shaft supports260is positioned adjacent to and on opposite sides of the second downshift element depression254b. Each of the shaft supports260includes a bore262that extends through the support for receiving a shaft, also as described below. The shaft supports260are positioned across the second downshift element depression254bfrom one another such that the bores262are concentrically aligned with one another.

As noted above, since the first and second downshift elements212aand212bhave the same construction, the first and second downshift element depressions254aand254bcan also have the same construction. However, the depressions254aand254bneed not have the same construction and can instead differ from one another as needed or desired for a particular application.

Lastly, the big chain ring152has a series of holes264a-dthat are provided to accommodate a portion of the upshift element210, as described below. The series of holes264a-dare arranged in an arc and are spaced apart from one another in a circumferential direction on the big chain ring152. The series of holes264a-dare also gradually different size and are arranged so that each successive hole is radially further away from the rotation axis R. In this example, the hole264ais closer to the rotation axis R and is the larger of the holes. Each successive hole264b-dis smaller than the prior hole and is further from the rotation axis R. More specifically, the hole264bis smaller and further from the axis R than the hole264a. The hole264cis smaller and further from the axis R than the hole264b. The hole264dis smaller and further from the axis R than the hole264c. In this example, there are four such holes264a-din the series. This number can differ, as will become apparent to those having ordinary skill in the art.

Referring toFIGS.17and18, the upshift element210is shown detached from the front shift unit150. In this example, the upshift element210has a body270with some openings272formed through the material of the body. The openings272may be provided to eliminate material of the body270to reduce the weight of and the material usage to form the upshift element210. The body270has an inboard facing side274with a series of contact surfaces276that are coplanar with one another and that lie on a chain ring contact plane C. A series of bores278a-eare provided through or in the body270of the upshift element210. The series of bores278a-eis arranged in an arc along the body210. In this example, there are five such bores278a-ein the series. This number can also differ, as will become apparent to those having ordinary skill in the art.

In this example, four of the bores278a-dof the series are each configured to receive a chain guiding peg280therein. A fifth bore278eof the series is configured to receive a chain upshifting hook282therein. In this example, the chain guiding pegs280and the chain upshifting peg282may each be fixed to the body270of the upshift element210within the respective bores278a-evia a corresponding series of set screws284. The set screws284are exposed along a top edge of the body270, which can generally follow the arc of the series of bores278a-e. The set screws284may be used to adjust and retain an angular or rotated position and an axial insertion or depth position of the chain guiding pegs280and the chain upshifting peg282relative to the body270of the upshift element210.

Referring toFIGS.19-22, each chain guiding peg280can be identical in construction and thus only one is described in detail herein. In this example, the chain guiding peg280has a cylinder-shaped barrel end286and a hook288projecting in an axial direction from the barrel end. The barrel end286is sized and configured to seat in one of the bores278a-d. The hook288has an angled top surface290and the barrel end286has an angled top portion292adjacent the angled top portion of the hook (seeFIG.22). Thus, the angled top surface290and angled top portion292are positioned to converge and meet between the barrel end286and the hook288and are configured for contacting the chain138, as described below. The hook288also has an angled bottom surface294opposite to and parallel with the angled top surface292. The hook288further has a plurality of chamfers296a-296con the tip and on edges of the hook.

Referring toFIGS.23-26, the chain upshifting peg282can be different from the chain guiding pegs280. In this example, the chain upshifting peg282has a cylinder-shaped barrel end300and a hook302projecting in an axial direction from the barrel end. The barrel end300is sized and configured to seat in the bore278ein the body270of the upshifting element210. The hook302is L-shaped with a portion spaced from the barrel end300(seeFIG.26). The hook302has a chamfer304at the tip and facing the barrel end300. The hook302is configured to contact and engage the chain138, as described below. The hook302also has a chamfer306on the bottom that faces away from the barrel end300and is opposite to and parallel with the chamfer304at the tip of the hook. The hook302also has a plurality of chamfers308a-308con the tip and on edges of the hook.

In this example, each of the chain guiding and chain upshifting pegs280and282may be formed from a hardened steel for wear resistance, durability, and strength. However, these peg and hook elements may be formed of other suitable materials, if desired. In another example, the upshift element210and the chain guiding and chain upshifting pegs280,282may be formed as one integral unit from the same material, if desired. Also, each of the chain guiding pegs280may instead be formed as a unique element to present the hook at a different, required depth. Further, the bores278a-ecan each be blind bores and the barrel ends286,300may each have a different length to automatically set the depth of each chain guiding and chain upshifting peg or element when installed. The barrels and bores can also be configured with features that will automatically set the rotational position of each peg when installed. Further, each bore may have a different size to aid in installing the correct peg element in the correct bore on the upshift element210.

As shown inFIG.17, the chain guiding pegs280and the chain upshifting peg282are arranged in a staggered, gradually receding insertion depth relative to the contact surfaces276on the body270and from the bore278ato the bore278e. More specifically, the angled top surface290and the tip of each hook288for each successive chain guiding peg280from the bore278ato the bore278dis closer to the plane C of the contact surfaces276than the previous one. Likewise, the chamfer304and the tip of the hook302of the chain upshifting peg282in the bore278eis closer to the plane C than the adjacent hook288of the chain guiding peg280in the bore278d. The purpose of this peg and hook arrangement is described in detail below.

The upshift element210also has a pair of gudgeons310that are spaced apart along and protrude from a bottom edge of the body270. Each gudgeon310has a through bore312oriented in a direction parallel with of the length of the body270. The through bores312of the gudgeons310are concentrically aligned with one another. The body270also has an adjustable set screw314extending widthwise or depth wise through upshift element210. The adjustable set screw314is threaded and engaged in a threaded hole through the body270. The purpose and function of the set screw314are described below.

As noted above, the first and second downshift elements212aand212bhave the same configuration and construction in this example.FIGS.27-29show the first downshift element212a, which is described in some detail. The description is equally applicable to the second downshift element212bas well and thus each is shown and referenced herein with the same features and reference numbers. In this example, the first downshift element212aincludes a body320with a proximal end, a distal end, and a fulcrum322disposed generally between the ends. A pair of coaxial holes324are disposed spaced apart across a width of the body320and define a pivot axis P at the fulcrum322.

The body320includes a drive arm326along one side of the body. The drive arm326extends radially relative to the axis P and from one of the holes324at the fulcrum322. The free end of the drive arm326is the proximal end of the body320in this example. A radial face of the drive arm326defines a cam surface328of the downshift element212a. The cam surface328includes a notch330. The other end of the body, opposite the drive arm326, terminates at the distal end. The other end has two legs332that extend radially relative to the axis P and from a respective one of the holes324at the fulcrum322. A head334is connected to the distal ends of the legs332. The proximal end of the head334connected to the legs332is thicker than the legs to define a contoured surface336(seeFIG.28) that faces radially inward toward the fulcrum axis P. However, the contoured surface336has a non-flat contour and is oriented at an angle, i.e., non-parallel relative to the axis P (seeFIGS.27and29). The head334also defines a contact face338on a tangential surface of the head. The contact face338is angled, i.e., non-parallel relative to a radial reference between the axis P and the distal end of the downshift element212a. The contact face338is configured to engage the chain138, as is described in more detail below.

In one example, the first and second downshift elements212aand212bmay be made from anodized aluminum. In another example, these elements may be made from other light weight, less expensive, and/or less durable materials. However, in such an example, the head334, or at least the contact face338portion thereof, may be made separately from a more durable, wear resistant material, such as hardened steel, and attached to the head or to the body320of the downshift element.

Referring toFIGS.30and31, the upshift element210of the front shifting system is associated with two upshift driving components that effect movement of the upshift element, as described in greater detail below. In this example, one of the upshift driving components is an upshift driver340depicted inFIG.30. The upshift driver340has a cylinder-shaped hub342with a central hole344formed axially through the hub. The upshift driver340rotates about the axis of the central hole344. Two torque protrusions346protrude axially from a face347of the hub342. The torque protrusions346are wedge shaped and are positioned 180 degrees opposite one another around the central hole344. The torque protrusions346are configured to transmit torque during use, as described below.

A drive body348of the upshift driver340protrudes radially from the hub342relative to the axis of the central hole344. A link hole350is formed through the drive body348. The link hole350has an axis that is parallel to, but spaced radially apart from, the axis of the central hole344. A threaded bore352is formed radially into the hub342and is oriented perpendicular to axis of the central hole344. A portion of the drive body348forms a first spring contact surface354that is configured and arranged to engage a torsion spring or return spring, as described below. In this example, the first spring contact surface354faces radially inward toward the axis of the central hole344but lies in a plane that is spaced from or tangential relative to the axis.

In this example, the other of the upshift driving components is an upshift actuator360depicted inFIG.31. The upshift actuator360also has a cylinder-shaped hub362with a central hole364formed axially through the hub. The upshift actuator360rotates about the axis of the central hole364. Two torque protrusions366protrude axially from a face368of the hub362. The torque protrusions366are also wedge shaped and are also positioned 180 degrees opposite one another around the central hole364. The face368of the upshift actuator360contacts the face347of the upshift driver340and the torque protrusions366are configured to rotationally engage the torque protrusions344on the upshift driver340to transmit torque during use, as described below.

An actuator arm370of the upshift actuator360protrudes radially from the hub362relative to the axis of the central hole364. A contact surface372on the actuator arm370faces in a circumferential direction. The contact surface372is configured to contact a portion of the upshift element210to move the element during use, as is described in further detail below. A portion of the actuator arm370forms a second spring contact surface374that is configured and arranged to engage a torsion spring or return spring, as described below. In this example, the second spring contact surface374also faces radially inward toward the axis of the central hole364but lies in a plane that is spaced from or tangential relative to the axis.

Referring toFIGS.32and33, the first downshift element212aof the front shifting system is associated with two downshift driving components that effect movement of the first downshift element, as described in greater detail below. In this example, one of the downshift driving components is a first downshift driver380depicted inFIG.32. The first downshift driver380also has a cylinder-shaped hub382with a central hole384formed axially through the hub. The first downshift driver380also rotates about the axis of the central hole384. Two torque protrusions386protrude axially from a face388of the hub382. The torque protrusions386are also wedge shaped and are positioned 180 degrees opposite one another around the central hole384. The torque protrusions386are configured to transmit torque during use, as described below.

A protrusion390of the first downshift driver380protrudes radially from the hub382relative to the axis of the central hole384. A threaded bore392is formed radially into the hub382and is oriented perpendicular to axis of the central hole384. An undercut portion of the protrusion390forms a first spring contact surface394that is configured and arranged to engage a torsion spring or return spring, as described below. In this example, the first spring contact surface394faces radially inward toward the axis of the central hole384but lies in a plane that is spaced from or tangential relative to the axis.

In this example, the other of the downshift driving components is a first downshift cam400depicted inFIG.33. The first downshift cam400has a cylinder-shaped hub402with a central hole404formed axially through the hub. The first downshift cam400rotates about the axis of the central hole404. Two torque protrusions406protrude axially from a face408of the hub402. The torque protrusions406are also wedge shaped and are also positioned 180 degrees opposite one another around the central hole404. The face408of the first downshift cam400contacts the face388of the first downshift driver380and the torque protrusions406are configured to rotationally engage the torque protrusions386on the first downshift driver380to transmit torque during use, as described below.

A cam arm410of the first downshift cam400protrudes radially from the hub402relative to the axis of the central hole404. A cam surface412on the cam arm410faces in an outward radial direction at the end of the cam arm. The cam surface412is curved, may be concentric with the axis of the central hole404, and is configured to contact a portion of the first downshift element212ato move the element during use, as is described in further detail below. An undercut portion of the cam arm410forms a second spring contact surface414that is configured and arranged to engage a torsion spring or return spring, as described below. In this example, the second spring contact surface414also faces radially inward toward the axis of the central hole404but lies in a plane that is spaced from or tangential relative to the axis.

Referring toFIGS.34and35, the second downshift element212bof the front shifting system is also associated with two downshift driving components that effect movement of the second downshift element, as described in greater detail below. In this example, one of the downshift driving components is a second downshift driver420depicted inFIG.34. The second downshift driver420also has a cylinder-shaped hub422with a central hole424formed axially through the hub. The second downshift driver420also rotates about the axis of the central hole424. Two torque protrusions426protrude axially from a face428of the hub422. The torque protrusions426are also wedge shaped and are positioned 180 degrees opposite one another around the central hole424. The torque protrusions426are configured to transmit torque during use, as described below.

A lobe430of the second downshift driver420protrudes radially from the hub422relative to the axis of the central hole424. A link hole432is formed through the lobe430. The link hole432has an axis that is parallel to, but spaced radially apart from, the axis of the central hole424. An undercut portion of the lobe430forms a first spring contact surface434that is configured and arranged to engage a torsion spring or return spring, as described below. In this example, the first spring contact surface434faces radially inward toward the axis of the central hole424. A curved portion of the first spring contact surface434is curved and is concentric with the axis of the central hole424but spaced from the hub422. A straight portion of the first contact surface434lies in a plane that is spaced from or tangential relative to the axis. A slot436is provided in the lobe430and extends in a plane perpendicular to the axis of the link hole432. The slot436also has a depth whereby it fully intersects the link hole432, which effectively divides the link hole432into two coaxial holes, one on each side of the slot436.

In this example, the other of the downshift driving components is a second downshift cam440depicted inFIG.35. The second downshift cam440is substantially similar to the first downshift cam400and thus also has a cylinder-shaped hub442with a central hole444formed axially through the hub. The second downshift cam440rotates about the axis of the central hole444. Two torque protrusions446protrude axially from a face448of the hub442. The torque protrusions446are also wedge shaped and are also positioned 180 degrees opposite one another around the central hole444. The face448of the second downshift cam440contacts the face428of the second downshift driver420and the torque protrusions446are configured to rotationally engage the torque protrusions426on the second downshift driver420to transmit torque during use, as described below.

A cam arm450of the first downshift cam440protrudes radially from the hub442relative to the axis of the central hole444. A cam surface452on the cam arm450faces in an outward radial direction at the end of the cam arm. The cam surface452is curved, may be concentric with the axis of the central hole444, and is configured to contact a portion of the second downshift element212bto move the element during use, as is described in further detail below. An undercut portion of the cam arm450forms a second spring contact surface454that is configured and arranged to engage a torsion spring or return spring, as described below. In this example, the second spring contact surface454also faces radially inward toward the axis of the central hole444but lies in a plane that is spaced from or tangential relative to the axis.

The assembled or installed configuration of the various components described above is now provided below. Throughout the following description of the assembled components of the front shift unit150, continued reference to numerous different figures may be helpful. Specific figures are identified below when describing the components of the assembled front shift unit150. However, there may also be other figures, though not specifically mentioned, that may be of interest below as well.

Referring toFIGS.10-13, a first cam shaft460extends between the shaft support240adjacent the upshifter recess238and the shaft support246adjacent the first downshifter recess244aon the big chain ring152(seeFIGS.14and15). The first cam shaft460extends through the bores242and248(seeFIGS.14and16) of the corresponding shaft supports240and246. A retainer, such as a snap ring or a retaining ring462(seeFIG.10) can be employed on at least one end or on both ends of the first cam shaft460to axially retain the shaft and prevent it from being withdrawn from the bores242,248in the shaft supports240,246.

Referring toFIGS.10-13, the upshift element210is rotatably supported on the first cam shaft460between the shaft supports240and246. More specifically, the first cam shaft is received through the bores312in the gudgeons310on the bottom edge of the body270of the upshift element210. Referring also toFIGS.5,13-15,18,36, and37, the series of bores278a-din the upshift element210align with respective ones of the series of holes264a-din the big chain ring152. Thus, the teeth288on the chain guiding pegs280, which are seated in the bores278a-din the body270of the upshift element210, are positioned to correspondingly align with the series of holes264a-din the big chain ring152. Further, referring toFIGS.5,14,15,36,37, the guard rail206, which is mounted to the big chain ring152, includes a bore264ethat is positioned radially outboard of the big chain ring152. The hook302on the chain upshift peg282, which is seated in the bore278ein the body270of the upshift element210, is positioned to correspondingly align with the hole264ein the guard rail206.

As can be seen inFIGS.5,14,15,36, and37, the big chain ring152includes a gap464among the sprocket teeth160on the perimeter of the chain ring. The hole264ein the guard rail206is positioned to align with the gap464. Thus, the hook302of the chain upshifting hook282also aligned with the gap464. As noted below, the series of holes264a-dare arranged in an arc and are spaced apart from one another in a circumferential direction on the big chain ring152. The series of holes264a-dare also gradually arranged so that each successive hole is radially further away from the rotation axis R, with the hole264abeing closer to the rotation axis R and the hole264dbeing further from the rotation axis. The hole264eis positioned to follow the same arc whereby the hole is still further from the rotation axis R than the adjacent hole264d. In this example, the hole264ein the guard rail206creates a fifth hole in the series of holes in the big chain ring152. Again, this number can differ, as will become apparent to those having ordinary skill in the art.

When the upshift element210is mounted to the big chain ring152, the upshift element can pivot about the axis of the first cam shaft460toward and away from the big chain ring152, as described further below. To accommodate, the teeth288of the chain guiding pegs280and the hook302of the chain upshifting peg282are also arranged in the same arc as the holes264a-e. Thus, the teeth288of the chain guiding pegs280can pass freely out of, and into and through, the corresponding holes264a-din the big chain ring152. Likewise, the hook302of the chain upshifting peg282can pass freely out of, and into and through, the hole264ein the guard rail206.

Referring toFIGS.10-13, an upshift biasing element, such as a torsion spring466, can be provided to bias the upshift element210in a desired direction. In this example, the torsion spring466is provided on the first cam shaft460. The torsion spring466has a first leg468seated in a notch470in the bottom edge on the body270of the upshift element210and engages the upshift element. The torsion sprig466also has a second leg472borne against the surface226of the big chain ring152. The legs468and472of the torsion spring466bias the upshift element210about the axis of the first cam shaft460in a direction toward the big chain ring152, which is counterclockwise inFIG.13.

The gearmotor unit200is seated in the motor recess232in the surface226on the big chain ring152. The hub216extending from the gearmotor unit200is positioned over the pocket234. One end, the proximal end, of the first link220ais pivotally connected to the hub216by the first pin222a, which is received through the hole in the proximal end of the link and is retained by one of the retaining rings224. The first link220aextends along the first recessed channel236ain the surface226of the big chain ring152. The upshift driver340is positioned over the upshifter recess238and the first cam shaft460is received through the central hole344in the hub342of the upshift driver. A first drive pin474ais received through the link hole350in the drive body348on the upshift driver340and though a hole in the other end, the distal end, of the first link220a. The first drive pin474aconnects the first link220ato the upshift driver340and is retained by another retainer, such as a snap ring or retaining ring476. In this way, the first link220ais rotatably connected to the upshift driver340. Referring toFIGS.10-12and30, a set screw478is received in the threaded bore352on the upshift driver340. In this example, the internal end of the set screw478can engage a flat surface (not shown) on the first cam shaft460to rotationally fix the upshift driver340to the first cam shaft so that rotation of the upshift driver rotates the first cam shaft, as described below.

Referring toFIGS.10-12and38, the upshift actuator360is also positioned over the upshifter recess238. The first cam shaft460is rotatably received through the central hole364in the hub362of the upshift actuator360. The actuator arm370is positioned facing and within the upshifter recess238. The upshift actuator360is positioned adjacent the upshift driver340on the first cam shaft460with their respective faces368and347closely confronting one another. The torque protrusions366of the upshift actuator360overlap axially with the torque protrusions346on the upshift driver340. Thus, the torque protrusion366and346can rotationally engage with one another. An upshift biasing element, such as a torsion spring, i.e., an upshift spring480is disposed on the first cam shaft460and axially between the upshift driver340and the upshift actuator360. A first leg (not shown) of the upshift spring480contacts or engages the first spring contact surface354on the upshift driver340. A second leg482of the upshift spring480contacts or engages the second spring contact surface374on the upshift actuator360. The upshift spring480is disposed and arranged to rotationally bias the torque protrusions346on the upshift driver340against the torque protrusions366on the upshift actuator360, as shown inFIG.38.

Referring toFIGS.10-12,32, and39, the first downshift driver380is positioned over the first downshifter recess244aand the first cam shaft460is also received through the central hole384in the hub382of the first downshift driver. A set screw486is received in the threaded bore392on the first downshift driver380. In this example, the internal end of the set screw486can engage another flat surface (not shown) on the first cam shaft460to rotationally fix the first downshift driver380to the first cam shaft so that rotation of the first cam shaft also rotates the first down shift driver, as discussed further below.

Referring toFIGS.10-12and39, the first downshift cam400is also positioned over the first downshifter recess244a. The first cam shaft460is rotatably received through the central hole404in the hub402of the first downshift cam. The cam arm410is positioned facing and within the first downshifter recess244a. The first downshift cam400is positioned adjacent the first downshift driver380on the first cam shaft460with their respective faces408and388closely confronting one another. The torque protrusions406of the first downshift cam400overlap axially with the torque protrusions386on the first downshift driver380. Thus, the torque protrusion406and386can rotationally engage with one another. A first downshift biasing element, such as a torsion spring, i.e., a first downshift spring490is disposed on the first cam shaft460and axially between the first downshift driver380and the first downshift cam400. A first leg (not shown) of the first downshift spring490contacts or engages the first spring contact surface394on the first downshift driver380. A second leg492of the first downshift spring490contacts or engages the second spring contact surface414on the first downshift cam400. The first downshift spring490is disposed and arranged to rotationally bias the torque protrusions386on the first downshift driver380against the torque protrusions406on the first downshift cam400, as shown inFIG.39.

Referring toFIGS.10-12,14-16, and39, the first downshift element212ais positioned over the first downshift element recess254ain the surface226of the big chain ring152. The fulcrum322of the first downshift element212ais received in the first downshift element recess254a. A first downshift shaft496ais received through the bores258of the supports256adjacent the first downshift element recess254a. The first downshift shaft494ais retained axially by a retaining element, such as a snap ring or retaining ring498aat each end of the shaft. The first downshift shaft496ais also received through the holes324at the fulcrum322to pivotally support the first downshift element212aon the shaft and relative to the supports256. A first downshifter biasing element, i.e., a first downshifter spring500a, such as a torsion spring, may be disposed on the first downshift shaft496a. A first leg (not shown) of the first downshifter spring500acan engage the surface226of the big chain ring152. A second leg502of the first downshifter spring500acan engage a spring contact surface504between the holes324of the fulcrum322on the first downshift element212a. The first downshift spring500ais configured and arranged to bias the head334and contact face338of the first downshift element212ain a direction away from the big chain ring152, the direction being counterclockwise inFIG.39.

Referring toFIGS.10-13and40, a second cam shaft506extends between the shaft supports250adjacent the second downshifter recess244bon the big chain ring152(seeFIGS.14and15). The second cam shaft506extends through the bores252(seeFIGS.14and16) of the shaft supports250. A pair of retainers, such as snap rings or retaining rings508(seeFIG.10) can be employed on the ends of the first cam shaft506to axially retain the shaft and prevent it from being withdrawn from the bores252in the shaft supports250.

Referring toFIGS.10-13and34, one end, the proximal end, of the second first link220bis pivotally connected to the hub216by the second pin222b, which is received through the hole in the proximal end of the second link and is retained by one of the retaining rings224. The second link220bextends along the second recessed channel236bin the surface226of the big chain ring152. The second downshift driver420is positioned over the second downshifter recess244band the second cam shaft506is rotatably received through the central hole424in the hub422of the second downshift driver. The other end, the distal end, of the second link220bis received in the slot436in the lobe430of the second downshift driver420A. A second drive pin474bis received through the link hole432in the lobe430and though a hole in the distal end of the second link220b. The second drive pin474brotatably connects the second link220bto the second downshift driver420and is retained by another retainer, such as a snap ring or retaining ring (not shown). In this way, the second link220bis rotatably connected to the second downshift driver420and drives rotation of the second downshift driver420, as described below.

Referring toFIGS.10-13and40, the second downshift cam440is also positioned over the second downshifter recess244b. The second cam shaft506is rotatably received through the central hole444in the hub442of the second downshift cam440. The cam arm450is positioned facing and within the second downshifter recess244b. The second downshift cam440is positioned adjacent the second downshift driver420on the second cam shaft506with their respective faces448and428closely confronting one another. The torque protrusions446of the second downshift cam440overlap axially with the torque protrusions426on the second downshift driver420. Thus, the torque protrusion446and426can rotationally engage with one another. A second downshift biasing element, such as a torsion spring, i.e., a second downshift spring512is disposed on the second cam shaft506and axially between the second downshift driver420and the second downshift cam440. A first leg (not shown) of the second downshift spring512contacts or engages the first spring contact surface434on the second downshift driver420. A second leg514of the second downshift spring512contacts or engages the second spring contact surface454on the second downshift cam440. The second downshift spring512is disposed and arranged to rotationally bias the torque protrusions426on the second downshift driver420against the torque protrusions446on the second downshift cam440, as shown inFIG.40.

Referring toFIGS.10-12,14-16, and40, the second downshift element212bis positioned over the second downshift element recess254bin the surface226of the big chain ring152. The fulcrum322of the second downshift element212bis received in the second downshift element recess254b. A second downshift shaft496bis received through the bores262of the supports260adjacent the second downshift element recess254b. The second downshift shaft494bis retained axially by a retaining element, such as a snap ring or retaining ring498bat each end of the shaft. The second downshift shaft496bis also received through the holes324at the fulcrum322to pivotally support the second downshift element212bon the shaft and relative to the supports260. A second downshifter biasing element, i.e., a second downshifter spring500b, such as a torsion spring, may be disposed on the second downshift shaft496b. A first leg (not shown) of the second downshifter spring500bcan engage the surface226of the big chain ring152. A second leg502of the second downshifter spring500bcan engage a spring contact surface504between the holes324of the fulcrum322on the second downshift element212b. The second downshift spring500bis configured and arranged to bias the head334and contact face338of the second downshift element212bin a direction away from the big chain ring152, the direction being counterclockwise inFIG.40.

The components of the front shifting system and the front shift unit150can vary in configuration and construction from the example shown and described herein. The specific components and component arrangement can also vary. More specifically, the characteristics, such as the shape, size, depth, height, width, length, and location of the features, including the various shaft supports, recesses, holes, and depressions, on the surface226of the big chain ring152can also vary. Some of the features and/or components may instead be part of or carried on the small chain ring154of the front shift unit150. Also, the physical details, such as the location, size, shape, structure, and material of the various drivers, actuators, cams, and upshift and downshift elements can vary from the examples described above. The type, size, location, and arrangement of the various sub-components, including the cam shafts, pins, links, and biasing elements, can also vary from the examples shown and described herein. Also, details, such as the location, type, arrangement, size, physical input and output characteristics, electrical power consumption, and mechanical power output, of the electro-mechanical and electronic components, including the gearmotor unit and the control unit, can also vary from the examples disclosed and described herein. As will be evident to those having ordinary skill in the art upon reading this disclosure, the front shifting system disclosed and described herein can function as intended though changes are made to the component examples.

The operation of the front shifting system is now described with continued reference to the drawings, as noted below, and to the above description of the components. The disclosed front shifting system has two shifting states and has two operational states. The operational states in this example include a first operational state, i.e., a big chain ring state, and a second operational state, i.e., a small chain ring state. In the big chain ring state, as shown inFIG.2, the chain138is on the big chain ring152and remains engaged with the sprocket teeth160on the big chain ring with the bicycle100in a corresponding gear and a rider pedaling the bicycle. In the small chain ring state, as shown inFIG.41, the chain138is on the small chain ring154and remains engaged with the sprocket teeth162on the small chain ring with the bicycle100in a corresponding gear and the rider pedaling the bicycle. One, more, or all of the front shifting system components may be in certain positions and arrangements in the big chain ring state and in different positions and arrangements in the small chain ring state. Alternatively, one, more, or all of the front shifting system components may be in the same positions and arrangements in each of the big chain ring and small chain ring states. In such examples, the components of the front shifting system can move from the big and/or small chain ring states to different, shifting states and arrangements in order to shift the chain138between the big and small chain rings152and154.

The front shifting states include a first state, i.e., an upshift state, and a second state, i.e., a downshift state. In the upshift state, the front shifting system and the components of the front shift unit150are operated, positioned or repositioned, and arranged to shift the chain138onto the big chain ring152and into engagement with the sprocket teeth160on the big chain ring. In the downshift state, the front shifting system and the components of the front shift unit150are operated, positioned or repositioned, and arranged to shift the chain138onto the small chain ring154and into engagement with the sprocket teeth162on the small chain ring. By operating the front shifting system, the chain138can be shifted or switched between the big and small chain rings to alter the gear rations of the drivetrain124.

Referring first toFIGS.2-6,10,11,13, and41-43, the upshift state of the front shift unit150is illustrated and the upshifting operation is now described. When a rider is riding the bicycle100in the small chain ring operational state, as depicted inFIG.41, with the chain138on and engaged with the small chain ring154, the rider may shift the bicycle using the shifter128. The rider may press a button on the shifter128to execute a gear shift or a shift change that results in the chain138shifting from the small chain ring154to the big chain ring152. This operation is defined herein as an upshift or an upshifting operation. Actuating the shifter128results in a wireless signal being sent by a radio transmitter or transceiver of the shifter to the front shift unit150. More specifically, the wireless signal may be received by a radio receiver or transceiver on the PCB of the control unit184. The wireless signal may be processed by the microprocessor of the PCB and then a signal and power is transmitted to the gearmotor unit200.

The output portion214and hub216are driven by the gearmotor unit200to rotate counterclockwise as depicted in and to the position shown inFIG.13. Rotation of the hub216in the counterclockwise direction moves the first link220adown and the second link220bup inFIG.13or, in other words, closer to the rotation axis R. This movement of the first link220acauses the upshift driver340to rotate in a counterclockwise direction to the position shown inFIG.13. This movement of the second link220bcauses the second downshift driver420to rotate in a clockwise direction to the position shown inFIG.13.

As the upshift driver340rotates counterclockwise to the position shown inFIGS.13and38, the torque protrusions346of the upshift driver engage the torque protrusions366of the upshift actuator360and rotate the upshift actuator in the counterclockwise direction in the figure. During the upshifting operation, unlike in the downshifting operation as described below, the upshift driver340directly drives rotation of the upshift actuator360without assistance or involvement of the upshift spring480. The upshift actuator360is then rotated to the position shown inFIGS.13and38. In the position shown, the actuator surface372on the actuator arm370of the upshift actuator360is clear and spaced from, and thus does not contact, the body270of the upshift element210. The clearance between the actuator surface372on the actuator arm370and the body270of the upshift element210is sufficient to allow the upshift element to rotate in the counterclockwise direction toward the surface226of the big chain ring152. The biasing force applied by the torsion spring466against the body270of the upshift element210drives rotation of the upshift element about the axis of the first cam shaft460.

However, the upshift element210is only free to fully rotate into the position shown inFIGS.13and38when the chain138, which is on the small chain ring154as depicted inFIG.41, is not blocking any of the holes264a-264din the big chain ring152and the hole264ein the guard rail206. The drivetrain124is operated in the direction of the arrow D, which rotates the gear shift unit150about the axis R, as shown inFIGS.2and47. The holes264a-264emay be partially blocked by the chain138for at least a fraction of one drivetrain rotation. As shown inFIG.41, the holes264a-264eare clear of the chain138when the guard rail206and the upshift element210are positioned on a rear end or back end of the front shift unit150and between upper (forward moving direction) and lower (rearward return direction) segments of the chain. As soon as the holes264a-264eare clear of the chain138, the torsion spring466biases the upshift element210to the position shown inFIGS.13and38adjacent the surface226of the big chain ring152.

As the upshift element210rotates further in the counterclockwise direction toward the surface226of the big chain ring152, the chain guiding pegs280and the chain upshifting peg282, each of which is carried on the upshifting element210, move through the corresponding holes264a-264etoward a plane S defined by the sprocket teeth162of the small chain ring154. The upshift element210rotates in the counterclockwise direction until the contact surfaces276in the plane C on the body270abut or contact the surface226of the big chain ring152. The fully rotated upshift state of the upshift element210is shown inFIGS.13and38.

As described above, the upshift driver340and the first downshift driver380are both fixed, via the respective set screws478and486, on and rotate in concert with the first cam shaft460. Thus, rotation of the upshift driver340in the counterclockwise direction causes rotation of the first cam shaft460, which in turn rotates the first downshift driver380in the same direction. This direction is counterclockwise inFIGS.13and38but is viewed as the clockwise direction inFIG.39because the cross-section through the first downshifting components in this figure is viewed from the opposite direction comparted to components shown in cross-section inFIGS.13and38. As the first downshift driver380rotates in the clockwise direction inFIG.39, the torque protrusions386on the first downshift driver engage the torque protrusions406on the first downshift cam400, which then rotates the first downshift cam in the clockwise direction to the position shown inFIG.39.

In this position, the first downshift cam400does not contact the first downshift element212a. In the position shown, the cam surface412on the cam arm410of the first downshift cam400is clear and spaced from, and thus does not contact the notch330on the cam surface328of the body320of the first downshift element212a. The clearance between the cam surface412on the cam arm410of the first downshift cam400and the cam surface328on the body320of the first downshift element212ais sufficient to allow the first downshift element to rotate in the counterclockwise direction about the fulcrum axis P inFIG.39. The first downshift element212ais rotated by the biasing force of the first downshifter spring500a. The first downshifter spring500abiases the first downshift element212ain the counterclockwise direction inFIG.39and thus moves the contact face338on the head334of the first downshift element212aaway from a plane B defined by the sprocket teeth160of the big chain ring152. In this upshifting state, as shown inFIG.39, the head334on the first downshift element212adoes not overlap the big chain ring152, i.e., does not intersect the plane B. Again, during the upshifting operation, unlike in the downshifting operation as described below, the first downshift driver380directly drives rotation of the first downshift cam400without assistance or involvement of the first downshift spring490.

Referring toFIGS.2-6,10,11,13,40, and41, movements of the second downshift element212band components for an upshifting operation and the upshift state are similar to those of the first downshift element212a. As noted above, the output portion214and hub216are driven by the gearmotor unit200to rotate counterclockwise as depicted in and to the position shown inFIG.13. Rotation of the hub216in the counterclockwise direction moves the second link220bup inFIG.13or, in other words, closer to the rotation axis R. This movement of the second link220bcauses the second downshift driver420to rotate in a clockwise direction to the position shown inFIG.13. This direction is clockwise in both ofFIGS.13and40. As the second downshift driver420rotates in the clockwise direction inFIG.40, the torque protrusions426on the second downshift driver engage the torque protrusions446on the second downshift cam440, which then rotates the second downshift cam in the clockwise direction to the position shown inFIG.40.

In this position, the second downshift cam440does not contact the second downshift element212b. In the position shown, the cam surface452on the cam arm450of the second downshift cam440is clear and spaced from, and thus does not contact the notch330on the cam surface328of the body320of the second downshift element212b. The clearance between the cam surface452on the cam arm450of the second downshift cam440and the cam surface328on the body320of the second downshift element212bis again sufficient to allow the second downshift element to rotate in the counterclockwise direction about the fulcrum axis P inFIG.40. The second downshift element212bis rotated by the biasing force of the second downshifter spring500b. The second downshifter spring500bbiases the second downshift element212bin the counterclockwise direction inFIG.40and thus moves the contact face338on the head334of the second downshift element212baway from the plane B of the big chain ring152. In this upshifting state, as shown inFIG.40, the head334on the second downshift element212balso does not overlap or intersect the plane B of the big chain ring152. Again, during the upshifting operation, unlike in the downshifting operation as described below, the second downshift driver420directly drives rotation of the second downshift cam440without assistance or involvement of the second downshift spring512.

In each ofFIGS.2-6,10,11,13,38-43, the front shifting system and the front shift unit150is depicted in the upshift state, as described above. However, the upshifting operation has not yet taken place. The angled contact surfaces338of the first and second downshift elements212aand212bare biased outward away from the plane B of the big chain ring152. Thus, the downshift elements212aand212bare positioned so as not to interfere with the chain138as the drivetrain124is operated by a rider and as the chain upshifts. Likewise, the chain guiding pegs and the chain upshifting peg protrude through the holes264a-264ein the big chain ring152and are positioned relatively close to the plane S of the small chain ring154and are ready to execute an upshift.

After the rider has actuated the shifter128to execute an upshift or upshifting operation, as the rider continues to pedal, the chain138is released from the small chain ring154and upshifts from the small chain ring154to the big chain ring152, as shown sequentially inFIGS.41and47-52. Referring toFIG.41, the chain138is carried on the small chain ring154and the rider is pedaling the drivetrain124, and the small chain ring, in the direction of the arrow D. The chain guiding pegs280and chain upshifting peg282are approaching from under, but have not yet reached, the chain138. Referring toFIG.47, a first or leading chain guiding peg280, which is protruding through the hole264aof the big chain ring152, encounters the chain138and begins to engage the chain.

FIGS.7-9depict various views of the chain138andFIG.53depicts a cross-section of the chain and the lead chain guiding peg280as the hook288engages the chain. The chain138and the sprocket teeth162on the small chain ring154are timed or synced such that the tip of the hook288on the chain guiding peg280rises into the tooth space170between a pair of the outer plates168of a chain link. As the rider continues to pedal and the front shift unit150continues to rotate in the arrow D direction, the chain link of the chain138is held by the hook288of the chain guiding peg280in a position that is further away in a radial direction from the rotation axis R of the front shift unit150compared to the position of the links of the chain forward of the chain guiding peg280and engaged with the small chain ring154. The outer plates168of the link on the hook288slide down from the tip of the hook along the angled top surface290(or the hook drives up into the tooth space170) from the position shown inFIG.53to the position shown inFIG.54. Thus, the chain138moves a relatively small distance to the right or the outboard direction away from the plane C of the small chain ring154toward the plane B of the big chain ring152.

FIGS.48-50show the subsequent sequential engagement of the remainder of the chain guiding pegs280with the chain138as the rider continues to pedal. As noted above, the chain guiding pegs280and the chain upshifting peg282are positioned gradually further outward in a radial direction relative to the rotation axis R of the front shift unit150. Likewise, each of the teeth288and302of the chain guiding pegs280and chain upshifting peg282is positioned axially further from the plane C of the small chain ring154. As shown inFIG.48, the next subsequent chain guiding peg280, which protrudes through the hole264bin the big chain ring154, enters the tooth space170between and engages the outer plates168of a subsequent or trailing link of the chain138. As the rider continues to pedal, the chain link of the chain138is held by the next subsequent hook288in a position that is further away in a radial direction from the rotation axis R compared to the position of the links of the chain engaged with the leading chain guiding element280. Also, the tip of the next subsequent hook288enters the tooth space170, as inFIG.53. The outer plates168of the link on the hook288again slide down or move relative to the tip of the hook along the angled top surface290from the position shown inFIG.53to the position shown inFIG.54. Thus, the chain138again moves a relatively small distance to the right or the outboard direction further away from the plane C of the small chain ring154toward the plane B of the big chain ring152and relative to the position of the chain on the leading chain guiding peg280.

Referring toFIGS.49and50, each of the next two subsequent chain guiding pegs280, which protrude through the holes264cand264d, will function in the same manner as the leading chain guiding peg280and the next subsequent chain guiding peg. Thus, the chain138will be guided further outward in a radial direction away from the rotation axis R by the sequence of chain guiding pegs280because the teeth288are positioned sequentially further from the axis. The chain138will also be guided further outboard toward the plane B of the big chain ring152by the sequence of teeth288on the chain guiding pegs280because the teeth are positioned sequentially closer to the plane B.

Referring toFIG.51, the chain upshifting peg282then subsequently engages a further trailing link of the chain138. Referring toFIG.55, a tip of the hook302of the chain upshifting peg282is positioned in the tooth space170between a pair of outer plates168of the link. As the rider continues to pedal, the link of the chain138is held by chain upshifting peg in a position that is again further outward in a radial direction from the rotation axis R compared to the preceding link on the preceding adjacent chain guiding peg280. The link of the chain138also slides down along the chamfered top surface304of the hook302from the position shown inFIG.55to the position shown inFIG.56. This moves the link of the chain138into alignment with plane B of the big chain ring152. Subsequent links of the chain138will then engage with the sprocket teeth160on the big chain ring152. As the rider continues to pedal and the front shift unit150continues to rotate about the rotation axis R, the chain will become fully engaged with the big chain ring152, as shown inFIGS.2and52.

As noted above, the sprocket teeth160on the big chain ring152can include alternating narrow teeth160nand wide teeth160w, which can respectively engage the narrow tooth spaces166between the inner plates164(i.e., narrow links) and the wide tooth spaces170between the outer links168(i.e., wide links) of the chain. The small chain ring154can also include such alternating narrow teeth162nand wide teeth162w. In this example, the chain guiding pegs280and chain upshifting peg282are timed or synced and spaced to engage the wide chain links and the teeth288and302are sized to engage the wide tooth spaces170. However, the chain guiding pegs and chain upshifting peg, and the respective teeth, can be sized and spaced to engage alternating wide and narrow links and tooth spaces of the chain or to engage only the narrow links and tooth spaces of the chain.

The guard206may be configured to have a specific height to protrude a desired radial distance outward relative to the position of the sprocket teeth160. The guard rail206may also be configured to have a specific length to cover a desired degree of arc of the big chain ring152. Likewise, the guard rail206can be placed on the big chain ring152relative to the chain upshifting peg282and spaced a desired distance to the outboard side of the big chain ring in order to limit outboard travel of the chain138as it upshifts onto the big chain ring. In other words, the guard rail206can be sized, shaped, and positioned as necessary to allow the chain138to engage the sprocket teeth160while preventing the chain from derailing to the outboard side of big chain ring during the upshifting operation. As the rider continues to pedal with chain138engaged with the big chain ring152, as shown inFIGS.2and52, the chain upshifting peg282and hook302can remain aligned with the plane B of the big chain ring152. Thus, the hook302may effectively act as an axial guide replacing or formed as a sprocket tooth of big chain ring152. The front shifting system and the components of the front shift unit150remain in the upshift state in this example until the rider requests or executes a downshift.

Referring next toFIGS.12and44-46, the downshift state of the front shift unit150is illustrated and the downshifting operation is now described. When the rider is riding the bicycle100and the chain138is engaged with the big chain ring152as inFIGS.2and52, the rider may wish to change gears. The gear change may require a downshift operation of the front shift unit150that shifts the chain138from the big chain ring152to the small chain ring154. The rider may press a button or operate an actuator of the shifter128on the handlebar assembly114. A wireless signal is then sent to the front shift unit150and is again received by the radio or wireless receiver or transceiver on the PCB of the control unit184. The processor or microprocessor of the control unit184then processes the signal and an appropriate signal and power is sent to the gearmotor unit200.

During the downshift operation, the gearmotor unit200is operated to drive or rotate the output portion214in a clockwise direction referring toFIGS.13and46. Operation of the gearmotor unit200and the output portion214in the clockwise direction causes the hub216to also rotate clockwise from the position shown inFIG.13to the position shown inFIG.46. Rotation of the hub216in the clockwise direction drives movement of the first link220aupward and the second link220bdownward to the positions shown inFIG.46. Upward movement of the first link220arotates the upshift driver340in a clockwise direction.

Referring toFIGS.38and57, as the upshift driver340rotates in the clockwise direction, the biasing force of the upshift spring480causes the upshift actuator360to also rotate in the clockwise direction in concert with the upshift driver340. This rotation keeps the torque protrusions366of the upshift actuator360firmly biased against and in contact with the torque protrusions346of the upshift driver340. As the upshift actuator360rotates in the clockwise direction, the actuator surface372of the upshift actuator360comes into contact and bears against the inboard side or face on the body270of the upshift element210. This rotation of the upshift actuator360thus biases or rotates the upshift element210also in the clockwise direction away from the surface226of the big chain ring152. Rotation of the upshift element210in the clockwise direction ofFIGS.38and57will thus withdraw the chain guiding pegs280and chain upshifting peg282, and their corresponding teeth288and302, away from the plane S of the small chain ring154and thus from the holes264a-264e.

It is possible that the rider may attempt to execute a downshift while the upshift element210is blocked from rotation in the clockwise direction away from the big chain ring154. This may occur when the chain138is blocking rotation of the upshift element210. For example, the chain138may block rotation of the upshift element210when the chain is on the big chain ring152as inFIG.2but is still engaged with the hook302of the chain upshifting peg282on the upshift element. When this occurs, the upshift element210and the upshift actuator360will remain stationary as the upshift driver340continues to rotate. As this occurs, the torque protrusions346of the upshift driver340will separate or move apart from the torque protrusions366of the upshift actuator360. The upshift spring480will thus wind up and store energy. The upshift element210will eventually become free to rotate in the clockwise direction, such as when the crank assembly132rotates to a position where the hook302on the chain upshifting peg282becomes free of the chain138. When the upshift element210is free to rotate, the upshift element and the upshift actuator360will rotate in the clockwise direction under the biasing force of the upshift spring480to the position shown inFIG.57.

As the upshift element210rotates in the clockwise direction, the chain guiding pegs280and the chain upshifting peg282, as noted above, move away from the plane S of the small chain ring154and clear the holes264a-264e. When the upshift element210is in the state as shown inFIGS.38and57, the direction or orientation of any force vector that might be transmitted through the first link220apasses substantially along the lengthwise axis of the first link and through the rotation axis of the gearmotor unit, i.e., the center of rotation of the hub216. In other words, if the upshift element210is subjected to an external force in the inboard or counterclockwise rotation direction (or even in the opposite direction), such as if the upshift element is struck by an object or is accidentally bumped by the rider, the force will not cause the hub216or the gearmotor unit200to be back driven or reverse rotated. This is because any such force vector is applied via the body270of the upshift element210, through the upshift actuator360and upshift driver340, and through the first link220aand will this not tend to cause any rotation of the hub216.

The set screw314along the lower edge of the body270on the upshift element210, which may be threadably received through the body, may be rotated or adjusted to fine tune or adjust the position of the upshift element210. The set screw314may be located on the body270of the upshift element210such that the actuator surface372on the upshift actuator contacts the free end of the set screw protruding from the body, instead of the upshift actuator directly contacting the upshift element210. Alternatively, the free end of the set screw314may be positioned to contact the surface226of the big chain ring152. In either case, the adjusted position of the set screw314can be used to determine the furthest inboard rotation position of the upshift element210, which is biased toward the surface226of the big chain ring152by the torsion spring466.

As described above, the upshift driver340and the first downshift driver380are both fixed to the first cam shaft460via the previously described set screws478and486. Thus, rotation of the upshift driver340in the clockwise direction ofFIGS.38and57also drives rotation of the first cam shaft460, and thus the first downshift driver380, in the same clockwise direction. Referring toFIGS.39and58, the first downshift element212ais shown from the opposite side compared toFIGS.38and57. Thus, the aforementioned clockwise rotation of the first downshift driver380inFIGS.38and57is shown in reverse or counterclockwise inFIGS.39and58. As the first downshift driver380rotates in the counterclockwise direction inFIGS.39and58, the biasing force of the first downshift spring490drives the first downshift cam400to rotate in the counterclockwise direction in concert with the first downshift driver380. The torque protrusions406of the first downshift cam400contact and are firmly biased against the torque protrusions386of the first downshift driver380. As the first downshift cam400rotates in the counterclockwise direction inFIG.58, the cam surface412on the cam arm410of the first downshift cam comes into contact with the cam surface328on the drive arm326of the first downshift element212a. This rotates the first downshift element212ain the clockwise direction inFIGS.39and58about the first downshift shaft496a. The first downshift element212ais rotated by this action from the position shown inFIG.39to the position shown inFIG.58.

Similar to the circumstance described above for the upshift element210, the first downshift element212amay be unable to immediately rotate in the clockwise direction upon an attempted execution of a downshift. For example, the chain138will block movement of the first downshift element212aif the first downshift element tries to move toward the plane B of the big chain ring152while the chain138is on the sprocket teeth160of the big chain ring. The head334on the body320of the first downshift element212awill instead contact the side of the chain138. If this occurs, the first downshift element212aand the first downshift cam400will remain stationary as the first downshift driver380continues to rotate, being driven by rotation of the first cam shaft460. The torque protrusions386on the first downshift driver380will rotate away and come out of contact with the torque protrusions406on the first downshift cam400. As a result, the first downshift spring490will wind up and store energy. As the crank assembly132continues to rotate, the first downshift element212awill eventually become free to rotate toward the plane B of the big chain ring152. This occurs when the first downshift element212ais positioned on the rear of the big chain ring152where the chain138is not engaged with the sprocket teeth160on the big chain ring. This position is shown inFIG.52where the first downshift element212ais rising upward toward the chain138but is adjacent a rear portion of the big chain ring152that is not engaged with the chain.

When the first downshift element212ais free to rotate, the first downshift cam400will rotate in the counterclockwise direction inFIGS.39and58under the biasing force of the first downshift spring490. Rotation of the first downshift cam400will drive rotation of the first downshift element212ain the clockwise direction ofFIGS.39and58about the first downshift shaft496a. As the first downshift element212arotates in the clockwise direction, the angled contact face338on the head334of the first downshift element moves toward the plane B of the big chain ring152until the head overlaps the plane and the sprocket teeth160, as shown inFIGS.46and58. In this state, first downshifter spring500abiases the first downshift element212ain the counterclockwise direction inFIG.58away from the plane B of the big chain ring152. Thus, the first downshifter spring500abiases the cam surface328on the drive arm326of the first downshift element212aagainst the curved cam surface412of the first downshift cam400, which holds the first downshift element212ain the downshift state overlapping the plane B of the big chain ring152.

If the first downshift element212aexperiences an external force that would otherwise move the first downshift element in the counterclockwise direction inFIG.58, the first downshift element would remain stationary in this state. For example, as the first downshift element212arises from under the chain138inFIG.52into contact with the chain, the force of the chain, and the force of the first downshifter spring500a, would tend to rotate the first downshift element about the first downshift shaft496ain the counterclockwise direction, pushing the head334outboard away from the plane B. However, the first downshift element212ain this downshift state is unable to move in the counterclockwise direction inFIG.58because the drive arm326on the body320of the first downshift element212ais borne against and blocked by the cam surface412of the first downshift cam400. In one example, the curvature of the cam surface412may be cylindrically shaped and concentric with the axis of the first cam shaft460. Thus, any force vector exerted by the cam surface328on the drive arm326of the first downshift element212aagainst the cam surface412of the first downshift cam400in the downshift state ofFIG.58would pass through the axis of the first cam shaft460. As a result, no amount of external force exerted by the chain138on the head334of the first downshift element212ain this downshift state would tend to cause rotation of first downshift cam400about the first cam shaft460. The force of the chain38thus will not cause the first downshift cam400or the first downshift element212ato be back driven or reverse rotated away from the plane B of the big chain ring152.

At this point, the front shifting system is in the downshift state, but a downshift has not yet been described or completed. Referring toFIGS.46,52,57, and58, the angled contact face338on the head334of the first downshift element212ais biased to overlap the plane B of the big chain ring152. Likewise, the upshift element210including the chain guiding pegs280and the chain upshifting peg282are biased in a direction away from the plane S of the small chain ring154. As the rider continues to pedal from the position of the front shift unit inFIG.52, the chain138downshifts from the sprocket teeth160of the big chain ring152to the small chain ring154as shown inFIG.59. More specifically, as the first downshift element212arises into contact with the chain138, the angled contact face338on the first downshift element blocks the chain from engaging the sprocket teeth160on the big chain ring152. Instead, the angled contact face338forces the chain138to redirect or deflect out of alignment with the plane B of the big chain ring in the inboard direction toward the plane S of the small chain ring154. As the rider continues to pedal the front shift unit150in the rotation direction R, the chain138will continue to wrap around and engage the sprocket teeth162of the small chain ring154as depicted inFIGS.41and47. After the downshift operation is complete, the front shifting system in this example remains in the downshift state until the rider requests or executes an upshift, as described above.

In one example, the outboard side surface226on the big chain ring152may include an elongate recess520associated with the position of each of the downshift elements, which includes the first and second downshift elements212aand212bin this example. These recesses520can extend from the outermost radius of the big chain ring152where the head334of each downshift element is positioned adjacent the sprocket teeth160. The recesses520can extend in a gradual spiral direction inward toward the sprocket teeth162of the small chain ring154. The recesses520can aid the chain138, by providing sufficient clearance between the chain and the surface226, when downshifting to the sprocket teeth162on the small chain ring154, as depicted inFIG.59with respect to the first downshift element212a.

In the disclosed example, the front shifting unit150has another, i.e., the second downshift element212bas noted earlier, not just the one or first downshift element212a, which is described above in detail. Referring again toFIGS.12and44-46, the downshift state of the front shift unit150is illustrated. During the above described downshift operation, when the rider presses a button or operates an actuator of the shifter128on the handlebar assembly114, a wireless signal is sent to the front shift unit150. The wireless signal is again received by the radio or wireless receiver or transceiver on the PCB of the control unit184. The processor or microprocessor of the control unit184then processes the signal and an appropriate signal and power is sent to the gearmotor unit200. When the first downshift element212ais actuated or moved to the downshift state, the second downshift element212bis also moved or actuated to the downshift state

Referring to the assembled front shift unit ofFIGS.10-12, the cross-section views ofFIGS.13and46, and the enlarged cross-section views ofFIGS.40and60, the movements of the second downshift element212band the corresponding components are now described during the downshift operation. During the downshift operation, the gearmotor unit200drives or rotates the output portion214and thus the hub216in the clockwise direction from the position shown inFIG.13to the position shown inFIG.46. Rotation of the hub216in the clockwise direction drives movement of the second link220bdownward from the position shown inFIG.13to the position shown inFIG.46. Downward movement of the second link220brotates the second downshift driver420in the counterclockwise direction from the position shown inFIG.13to the position shown inFIG.46about the second cam shaft506.

As the second downshift driver420rotates in the counterclockwise direction inFIGS.40and60, the biasing force of the second downshift spring512drives the second downshift cam440to rotate in the counterclockwise direction in concert with the second downshift driver420. The torque protrusions446of the second downshift cam440contact and are firmly biased against the torque protrusions426of the second downshift driver420. As the second downshift cam440rotates in the counterclockwise direction inFIG.60, the cam surface452on the cam arm450of the second downshift cam comes into contact with the cam surface328on the drive arm326of the second downshift element212b. This rotates the second downshift element212bin the clockwise direction inFIGS.40and60about the second downshift shaft496b. The second downshift element212bis rotated by this action from the position shown inFIG.40to the position shown inFIG.60.

Similar to the circumstance described above for the first downshift element212a, the second downshift element212bmay be unable to immediately rotate in the clockwise direction toward the plane B of the big chain ring152upon an attempted execution of a downshift. For example, the chain138will again block movement of the second downshift element212bif the second downshift element tries to move toward the plane B of the big chain ring152while the chain138is on the sprocket teeth160. The head334on the body320of the second downshift element212bwill instead contact the side of the chain138. If this occurs, the second downshift element212band the second downshift cam440will remain stationary as the second downshift driver420continues to rotate, being driven by rotation of the hub216and the second link220b. The torque protrusions426on the second downshift driver420will rotate away and come out of contact with the torque protrusions446on the second downshift cam440. As a result, the second downshift spring512will wind up and store energy. As the crank assembly132continues to rotate, the second downshift element212bwill eventually become free to rotate toward the plane B of the big chain ring152. Again, this occurs when the second downshift element212bis positioned on the rear of the big chain ring152where the chain138is not engaged with the sprocket teeth160on the big chain ring. This position is not shown (though it would be similar to the position of the first downshift element212ainFIG.52) but would occur when the second downshift element212bis rising upward toward the chain138but is adjacent a rear portion of the big chain ring152that is not engaged with the chain.

When the second downshift element212bis free to rotate, the second downshift cam440will rotate in the counterclockwise direction inFIGS.40and60under the biasing force of the second downshift spring512. Rotation of the second downshift cam440will drive rotation of the second downshift element212bin the clockwise direction ofFIGS.40and60about the second downshift shaft496b. As the second downshift element212brotates in the clockwise direction, the angled contact face338on the head334of the second downshift element moves toward the plane B of the big chain ring152until the head overlaps the plane and the sprocket teeth160, as shown inFIGS.46and60. In this state, second downshifter spring500bbiases the second downshift element212bin the counterclockwise direction inFIG.60away from the plane B of the big chain ring152. Thus, the second downshifter spring500bbiases the cam surface328on the drive arm326of the second downshift element212bagainst the curved cam surface452of the second downshift cam440, which holds the second downshift element212bin the downshift state overlapping the plane B of the big chain ring152.

As with the first downshift element212adescribed above, if the second downshift element212bexperiences an external force that would otherwise move the second downshift element in the counterclockwise direction inFIG.60, the second downshift element would remain stationary in this state. For example, as the second downshift element212brises from under the chain138(not shown) into contact with the chain, the force of the chain, and the force of the second downshifter spring500b, would tend to rotate the second downshift element about the second downshift shaft496bin the counterclockwise direction, pushing the head334outboard away from the plane B. However, the second downshift element212bin this downshift state is unable to move in the counterclockwise direction inFIG.60because the drive arm326on the body320of the second downshift element212bis borne against and blocked by the cam surface452of the second downshift cam440. Again, the curvature of the cam surface452may be cylindrically shaped and concentric with the axis of the second cam shaft506. Thus, any force vector exerted by the cam surface328on the drive arm326of the second downshift element212bagainst the cam surface452of the second downshift cam440in the downshift state ofFIG.60would pass through the axis of the second cam shaft506. As a result, no amount of external force exerted by the chain138on the head334of the second downshift element212bin this downshift state would tend to cause rotation of second downshift cam440about the second cam shaft506. The force of the chain38thus will not cause the second downshift cam440or the second downshift element212bto be back driven or reverse rotated away from the plane B of the big chain ring152.

As with the first downshift element212a, at this point, the front shifting system is in the downshift state, but a downshift has not yet been completed. Referring toFIGS.46,52(for general reference), and60, the angled contact face338on the head334of the second downshift element212bis biased to overlap the plane B of the big chain ring152. The upshift element210including the chain guiding pegs280and the chain upshifting peg282are biased in a direction away from the plane S of the small chain ring154. As the rider continues to pedal from a position of the front shift unit150that is 180 degrees rotated from the position inFIG.52, the chain138downshifts from the sprocket teeth160of the big chain ring152to the small chain ring154as shown inFIG.59. More specifically, as the second downshift element212brises into contact with the chain138, the angled contact face338on the second downshift element blocks the chain from engaging the sprocket teeth160on the big chain ring152. Instead, the angled contact face338forces the chain138to redirect or deflect out of alignment with the plane B of the big chain ring in the inboard direction toward the plane S of the small chain ring154. As the rider continues to pedal the front shift unit150in the rotation direction R, the chain138will continue to wrap around and engage the sprocket teeth162of the small chain ring154as depicted inFIGS.41and47. After the downshift operation is complete, the front shifting system in this example remains in the downshift state until the rider requests or executes an upshift, as described above.

In the disclosed example, the upshift element210is in the upshift state rotated to the position adjacent the big chain ring152when executing an upshift operation and thereafter, until being moved for the next downshift. At the same time, the downshift elements212aand212bare rotated to the position not overlapping the sprocket teeth160of the big chain ring152. In this position, the downshift elements212aand212bare positioned so as not to engage the chain138. This downshift element position may be described as a neutral state, though the system as a whole is in the upshift state. Likewise, the downshift elements212aand212bin the downshift state are rotated to the position overlapping the sprocket teeth160of the big chain ring152when executing a downshift operation and thereafter, until being moved for the next upshift. At the same time, the upshift element210is rotated to the position away from the big chain ring152. In this position, the upshift element210is positioned so as not to engage the chain138. This position may also be described as a neutral state herein, though the system as a whole is in a downshift state.

As noted above, the front shift unit150in this example includes two downshift elements212aand212b. The two downshift elements are oriented about 180 degrees opposite one another on the big chain ring152. Thus, the downshift elements provide two opportunities to execute or perform a downshift per each revolution of the crank assembly132. As a result, a downshift operation can be executed faster than if the front shift unit150had only one downshift element. However, the front shifting system can be provided in an alternate example with only one downshifting element or can be provided with more than two downshifting elements. In this example, the front shift unit150includes only one upshift element210, along with the two downshift elements212aand212b. In an alternate example, the front shift unit may include a second or more upshift elements as well. The front shifting system may include any number of upshift elements and/or downshift elements within the sprit and scope of the disclosure. Increasing the number of upshift and downshift elements will decrease the average time that it takes to complete a shift by placing a next available shift element that much closer to the upper working side of the chain when a shift is requested or executed.

Referring toFIGS.19-26, a rider sometimes may pedal the crank assembly backwards opposite to the rotation direction R. In the event that the rider pedals backwards and while the upshift element210is in the upshift state, the position and shape of the teeth288on the chain guiding pegs280and the position and shape of the hook302on the chain upshifting peg282can be configured and arranged to deflect or reject the chain138. More specifically, the angled bottom surface294and the chamfered surfaces or chamfers296a,296b, and296con the teeth288and the angled bottom surface306and the chamfered surfaces or chamfers308a,308b,308con the hook302are configured so that the chain138does not engage with the chain guiding pegs280or the chain upshifting peg282. These angled surfaces and chamfers protect against a chain derailment that could occur if the chain138were to engage the chain guiding pegs280or the chain upshifting pegs while the rider is pedaling backwards. The angled bottom surface294and chamfers296a,296b, and296con the teeth288and the angled bottom surface306and chamfers308a,308b, and308con the hook302may also function to deflect or reject the chain138when the chain guiding pegs280and the chain upshifting peg282cross over or rotate past the bottom or slack side of the chain after the upshift element210is biased or positioned in the upshift state, but before an upshift operation has occurred.

In another example, with reference toFIG.61, the front shifting system may include an optional power meter530that is deployed and configured to measure the rider's power output while pedaling the bicycle100. In this example, the power meter530is provided as a part of a modified front shift unit532. The power meter530may include strain measurement devices attached to the material of the chainring structure between a torque input and output section so as to measure power transmitted therethrough. The power meter530may include an independent PCB including appropriate circuitry to determine, and/or transmit signals indicative of, power transmitted through the chainring structure. Electrical power to operate the power meter530may be supplied by the power supply194via a cable (not shown) extending from the power supply to the power meter. In another embodiment, the power meter530and the front shift unit532may share PCB within the control unit184, rather than having a separate PCB for the power meter and the front shift unit. In this embodiment strain measurement devices may still be attached to the chainring structure and configured to measure strain of the chainring structure.

In one example, the big chain ring152may have forty-eight (48) sprocket teeth160and the small chain ring154may have thirty-two (32) sprocket teeth162. In such an example, both the number of sprocket teeth160on the big chain ring152and the number of sprocket teeth162on the small chain ring154are multiples of four. Such an arrangement allows the downshift elements212aand212bto be positioned 180 degrees offset or apart from each other around the circumference of the front shift unit150. Also, for each of the two downshift element locations, the spatial relationship or timing between the relevant teeth160on the big chain ring152and the relevant teeth162on the small chain ring154will be the same. In this way, the front shift unit150can be designed such that the rotational timing between the big chain ring and the small chain ring provides a high quality upshift component geometry and a high quality first downshift component geometry, while also assuring the second downshift component geometry will be identical to the first downshift component geometry. Thus, in the disclosed example, the number of teeth160on the big chain ring152and the number of teeth162on the small chain ring154are both multiples of four. However, the disclosed front shifting system and front shift unit are not limited to such a chain ring design. Any number of teeth can be provided on either of the chain rings.

As described above, the position of the upshift element210is adjustable by manipulating the set screw314. In the disclosed example, there is no device or mechanism disclosed to adjust the position of the downshift elements212aand212b. However, a device or mechanism associated with these elements may be included that allows adjustment. For example, the downshift element212acould be provided in two parts. One part may include the contact face338on the head334and a second part may include the cam surface328and the drive arm326. Both of the parts may then be independently rotatable about the first downshift shaft496a. A set screw may be threadably engaged with one of the two parts and may have an exposed end in contact with the other of the two parts. The set screw may then be used to adjust the position of the contact face338of the head334relative to the cam surface328on the drive arm326. The specific construction of such an adjustable downshift element construction is not described further herein.

Referring toFIGS.14,15,36, and37, some teeth160of the big chain ring152and some teeth162of the small chain ring154may be provided having a special or different shape than other of the teeth. For example, two of the teeth160of the big chain ring152that immediately precede the location of the downshift elements212aand212bmay have an outboard face540with material that has been removed from the outboard surface of the teeth. This tooth shape may be provided on these two specific teeth160to allow the chain138to more easily deflect inboard during a downshift operation. In another example, one specific tooth160of the big chain ring152that immediately precedes the position of the chain upshifting peg282and the hole264emay have an inboard face542with material that has been removed from the inboard surface of the tooth. This tooth shape may be provided to allow the chain138to deflect or move slightly farther outboard before engaging the hook302of the chain upshifting peg282during an upshifting operation. In another example, a series of the teeth162of the small chain ring154are the first teeth to engage the chain138during a downshift operation. These teeth may have special chamfers544on the tooth surfaces to optimize chain management during a downshift operation. In still another example, a series of the teeth160of the big chain ring152are the first teeth to engage the chain138after an upshift operation. These teeth may also have special chamfers546on the tooth surfaces to optimize chain management during an upshift operation.

In an alternate example, the front shifting system may be configured for what is termed “synchro shifting.” In synchro shifting, when a rider requests or executes an upshift or a downshift, the front shifting system automatically determines the combination of which front chain ring, i.e., the big chain ring152or the small chain ring154, and which sprocket of the rear cassette140should engage the chain138. The front shifting system and rear derailleur then shift the chain to the desired front chain ring and rear sprocket accordingly. The “synchro shift” system can be configured to shift through every available gear combination in sequence, from the highest gear to the lowest gear, and vice versa.

In another alternate example, the front shifting system, and the rear shifting system as well, can be configured for automatic shifting. In an automatic shifting system, the bicycle can be configured with sensors that sense various drive train operational characteristics, which are used to shift gears automatically. Any one or more of the sensed operational characteristics may be sensed and used to determine when the system should shift gears. For example, such operational characteristics can include pedaling torque, pedaling cadence, speed, and changes in such characteristics over time. The front shifting system and rear shifting system can be configured to automatically shift gears on the bicycle, without direct input from the rider, when a predetermined combination of one or more of these characteristics is sensed or determined.

In another alternate example, the front shifting system, as well as the rear shifting system, can be configured as what is known as a half-step system. Half-step shifting is a known shifting technique where the gear ratio change between successive rear sprockets is approximately double the gear ratio change between the front chain rings. When shifting the chain either up or down on the sprockets of the rear cassette, the half-step system can shift the chain on the front chain ring component between the front chain rings during every shift and can shift the chain between the rear sprockets every other shift. In this type of half-step system, very small, sequential gear ratio changes can be achieved.

The disclosed front shifting system and front shift unit150is a two-state system. The disclosed two state system has only two states, which include a downshift state and an upshift state. In the downshift state, the parts or components are arranged to downshift the chain from a big chain ring to a smaller chain ring and then remain in that state until asked to execute an upshift operation. In the upshift state, the parts or components are arranged to upshift the chain from a small chain ring to a bigger chain ring and then remain in that state until asked to execute a downshift operation. In an alternate example, the front shifting system and the front shift unit may be configured as having three states. The three states can include an upshifting state, a downshifting state, and a different, neutral state for the upshifting and downshifting elements. The parts or components can be arranged in the upshifting state only when executing an upshift of the chain and can be arranged in the downshifting state only when executing a downshift of the chain. The part or components can be configured to return to and be arranged in a neutral state when not executing an upshift or a downshift of the chain. In other words, the front shifting system can be in the neutral state when neither the upshift element or elements nor the downshift element or elements are engaged or arranged to upshift or downshift, respectively, the chain. The parts or components of the front shifting system and front shift unit150can thus be configured to be in the neutral state when the rider is riding the bicycle and no shifting occurs.

In another alternate example, the gearmotor unit200and the electronic control unit184may be contained or housed within the same housing or enclosure, rather than having separate housings, as in the above-described example. The gearmotor unit and electronic control unit can be provided as a single controller, which provides the functions of both the gearmotor unit and the electronic control unit.

In one example, the big chain ring152and the small chain ring154may be integrally formed as one single part or chain ring component228, as in the disclosed example. In an alternate example, the big chain ring and the small chain ring may instead be separately formed components that are then either directly fixed to one another to form the chain ring component indirectly joined to one another via a third component, such as a chain ring hub.

In one example, the various shifting mechanisms, parts, or components of the front shift unit150are all directly mounted to the chain ring component. In the disclosed example, virtually all of the shifting mechanisms, parts, or components are formed as an integrated part of, or mounted to, the big chain ring152. In an alternate example, one, more than one, or all of the various shifting mechanisms, parts, or components may be formed as an integrated part of, or mounted to, the small chain ring154. In yet another alternate example, one, more than one, or all of the various shifting mechanism, parts, or components of the front shifting system and front shift unit may be mounted to a different, separate part (not shown) of the unit. That separate part may then in turn be mounted to the front shift unit. For example, one, more than one, or all of the various shifting mechanisms, parts, and components may be mounted to the cowling of the front shift unit.

It is well known in the bicycle field that, during a pedal stroke, the torque that a rider inputs to the crank assembly132varies as a function of the angular position of the crank arms134. In the disclosed example, the crank arms134of the crank assembly132are angularly positioned relative to the upshift element210and the downshift elements212aand212bsuch that the pedal torque input by the rider is not near a maximum torque during an upshift operation or a downshift operation. In an alternate example, the crank arms134of the crank assembly132may be located at a different angular position relative to the position of the upshift element210and the downshift elements212aand212b.

Specific materials are disclosed above for some of the shifting mechanisms, parts, or components. The disclosed front shifting system and front shift unit150is not limited to only those specific materials, or to any specific materials for any of the mechanisms, parts, or components. Other suitable materials may certainly be utilized. In just one alternate example, the upshift element210may be made from an injection molded nylon material or a long fiber reinforced thermoplastic material. In another example, the chain guiding pegs280and the chain upshifting peg282may insert molded in place on the body270of the upshift element210. This would eliminate the need for individually adjusting the position of each peg relative to the plane C of the contact surfaces276on the body270. Other such modifications may certainly be made to the upshift element and to other of the various shifting mechanisms, parts, or components as well.

In another alternate example, the front shift unit150may be configured to include additional sensors, such as a three-axis gyroscope and/or a three-axis accelerometer. Such components may be disposed on the PCB of the electronic control unit184or on another suitable part of the front shift unit. These additional sensors may be employed to determine the angular position and/or the angular velocity of the front shift unit150during pedaling. Such positional and velocity information may be used to improve performance of the front shifting system, as discussed in more detail below. Other types of additional sensors may also be used to obtain additional data and information, as desired.

In one example, the front shifting system, as well as the rear shifting system, may be configured to disallow or prohibit shifting of the gears when a rider is not pedaling the bicycle100forward or, in other words, when the angular velocity of the front shift unit150is not greater than zero in the rotation direction R. The front shifting system, as well as the rea shifting system, may alternatively be configured to disallow or prohibit shifting when the rider is not pedaling the bicycle faster than a predetermined threshold value or, in other words, when the angular velocity of the front shift unit150is not greater than the predetermined threshold value. This feature may be added to aid in preventing a chain derailment or other undesired system behavior.

In another example, the front shifting system, as well as the rear shifting system, may be configured to abort a shift that is in progress if a rider pedals backwards during a shifting operation. If the rider pedals backwards during the execution of a shift, the front shifting system, as well as the rear shifting system, may revert to the previous state, prior to the beginning the shift, rather than continue the shifting operation. This feature may also be added to aid in preventing a chain derailment or other undesired system behavior.

In another example, the front shifting system, as well as the rear shifting system, may be configured to delay shifting until a desired angular position of the front shift unit150has been achieved. This feature can be achieved by employing one or more sensors to obtain two axes of accelerometer data. The collected data can be used to determine the near real time angular position of the front shift unit150relative to the gravity vector. For example, a sensor, such as an accelerometer, may be mounted to the bicycle frame102and may be used to determine the orientation of the bicycle100relative to the gravity vector. The orientation of the front shift unit150relative to the bicycle100can then be determined. Shifting of the front shift unit150can be delayed until a desired angular position of the front shift unit has been achieved. The frame-mounted sensor may be eliminated if the errors associated with its absence are small.

In another example, the front shifting system may be configured to move the upshift element210and/or the downshift elements212aand212bto an intermediate position until a shift is completed. After the shift is completed, the upshift element210and the downshift elements212aand212bcan be moved to a final, steady-state position. In one example, this feature may be used to optimize the positions of the upshift element210and/or the downshift elements212aand212bbased on a position of the rear sprocket or cog of the rear cassette140that is engaged with the chain138, i.e. based on the chain line or chain angle.

FIGS.62-74show an embodiment in which the power supply, PCB, motor, shift mechanism and associated parts are attached to and supported by a mechanism support bracket661, rather than being directly attached to and supported by a chain ring component655. The power supply, PCB, motor, shift mechanism and associated parts, together with the mechanism support bracket661are included in a mechanism module660that attaches to the chain ring in a way that will be described further herein. A first advantage of the embodiment is that it allows the mechanism module and chain ring component to be replaced independently of each other. For example, if the chain rings are worn, they can be easily replaced by the end user without replacing the mechanism module. A second advantage of the embodiment is that it may simplify and reduce the costs involved in the manufacture of the chain ring component. A third advantage of the embodiment is that the housing of the mechanism module covers the mechanism, protecting it from dirt and debris. A fourth advantage of the embodiment is that it may improve aerodynamics without the need of a separate cowling.

Referring toFIGS.62and63, mechanism module660attaches to front shifting unit650with a plurality of fasteners, for example five screws662that thread into corresponding threaded holes in front shifting unit650. Other attachment techniques may be used. For example, rivets or other fasteners may be used to attach corresponding features of the parts.

FIGS.63-66show the mechanism module660, andFIGS.67-69show the mechanism support bracket661of mechanism module660. Referring toFIGS.67-69, mechanism support bracket661has a plurality of holes672, five in this embodiment, configured to receive the aforementioned plurality of screws to attach mechanism module660to front shifting unit650.

Referring toFIGS.67and69, shafts630,631,632,633are located in and supported by corresponding holes in mechanism support bracket661, and perform the same functions as shafts460,496a,496b,506of previous embodiments. Referring toFIG.65, gearmotor unit200is screwed to mechanism support bracket661with two screws186that are threaded into threads in mechanism support bracket661. First and second downshift elements612a,612bare pivotably received on and supported by first and second downshift pivot shafts631,633, respectively. First and second downshift element biasing springs623,624are received on and supported by first and second downshift pivot shafts631,633, respectively. First legs of first and second downshift element biasing springs623,624engage first and second downshift elements612a,612b, respectively, and second legs of first and second downshift element biasing springs623,624engage mechanism support bracket661. First and second downshift element biasing springs623,624bias first and second downshift elements612a,612bin the same way as in previous embodiments.

Referring toFIGS.70-72upshift element603may be made of long fiber reinforced thermoplastic (“LFRT”), glass-filled nylon, or other appropriate materials such as some metallic materials, and chain guiding elements604and chain upshifting element605may be made of hardened steel or other material operable to carry the appropriate chain upshifting and/or guiding loads and that may provide appropriate chain interaction and wear characteristics. Chain guiding elements604and chain upshifting element605are preferably insert molded into upshift element603. Thus, upshift element603, chain guiding elements604and chain upshifting element605all may behave as one unitary member. In other embodiments, the upshift elements and/or chain guiding elements may operate independently. Stop surfaces674project from upshift element603and stop against front shifting unit650when upshift element603is in the upshift position, preventing further rotation of upshift element603.

Referring toFIG.65, upshift element603is pivotably received on and supported by first cam shaft630. Upshift element biasing spring622is also received on and supported by first cam shaft630. A first leg of upshift element biasing spring622engages upshift element603, and a second leg of upshift element biasing spring622engages mechanism support bracket661. Upshift element biasing spring622biases upshift element603in the same way as in previous embodiments.

The remaining parts associated with the mechanism (cams, drive elements, springs, links, hub, etc.) may be supported and attached as described in previous embodiments.

Referring toFIG.64, power supply latch196is pivotably attached to an axle fixed to mechanism support bracket661. Printed circuit board (or PCB, seeFIG.63)626is housed inside a waterproof chamber in mechanism support bracket661. Button676of PCB626is accessible through a hole in mechanism support bracket661, and LED192of PCB626is visible through a clear lens in mechanism support bracket661. Electrically conductive pogo pins of PCB626protrude from holes in mechanism support bracket661, and electrically connect to terminals of power supply194, which is attachable to (and removable from) mechanism module660by operation of latch196. Wires (not shown) carry electrical power and signals from PCB626to gearmotor unit200.

Referring toFIGS.73and74, front shifting unit650has a plurality of holes678, which may be the five threaded holes described in this example, that receive the aforementioned fasteners (e.g. the five screws) that attach mechanism module660to front shifting unit650. Machining of the front shifting unit650is simplified compared to other embodiments, since difficult-to-machine cross-drilled holes of other embodiments are omitted, and are replaced with threaded holes678which are machined from the same direction as other features in front shifting unit650. Further, the omission of the bosses on which the cross-drilled holes were located results in a machining “blank” that is thinner, greatly reducing the amount of material that must be removed during the machining operation.

Referring toFIGS.69and74, mechanism support bracket661has two surfaces680,682that engage and abut corresponding surfaces684,621in front shifting unit650to transfer chain loads from the chain to front shifting unit650as follows. During an upshift operation, the chain load is carried by chain guiding elements604and chain upshifting element605. The chain load is transferred through chain guiding elements604and chain upshifting element605, through upshift element603, through first cam shaft630, through mechanism support bracket661, through surfaces680,682of mechanism support bracket661, to surfaces684,621of front shifting unit650. In this manner, screws662are not required to carry the chain load during an upshift operation.

FIG.75shows an alternate embodiment in which removable power supply194is omitted, and instead, non-removable power supply663is permanently installed inside mechanism module660. Non-removable power supply663performs the same function as removable power supply194, and preferably includes circuitry and structure providing the power supply663as rechargeable. Non-removable power supply663is electrically connected to PCB626.

FIG.76shows an alternate embodiment in which power supply194is again omitted, and power supply664is received inside the hollow space formed inside spindle665. Power supply664is preferably connected by conductive cables and/or wires (not shown) to PCB626. Power supply664performs the same function as power supply194, and is preferably rechargeable. Power supply664may be removable, or may be permanently installed.

FIG.77shows a power meter530that is incorporated into all of these embodiments. The power meter embodiment shown is well known in the art, and uses strain gauges that are attached to front shifting unit650in order to measure the rider's torque output. The power meter530also may include sensors to measure the rider's cadence. Using this torque and cadence data, the power meter530calculates the power output of the rider. The power meter530may receive electrical power from the same batteries194,663, and/or664that power the shift mechanism, or the power meter may receive electrical power from a separate power meter power supply686as shown inFIG.77. The power meter530may be covered by a waterproof cover (cover removed inFIG.77for clarity).

As previously indicated, and as will be discussed with reference toFIG.5B, exchanging, or shifting, a chain between two or more sprockets152,154may be accomplished with at least one (“1”) shift element288being moved into a chainline of a drive system. Shift elements288,302are chain engaging elements such as pegs, hooks, or other elements as described herein. Shift elements are configured to engage a link or plate of a chain. In the described embodiments, a single shift element engages a singular link or link plate. The shift elements may be protruding shift elements that move in an axial direction relative to a rotational axis R of the sprockets. The protruding shift elements may be configured to extend and/or retract in the axial direction for moving into and/or out of the chainline to engage the chain. The at least one moving shift element may be disposed radially between a root circle R3of a larger sprocket and a tooth tip circle of a smaller sprocket R2. The at least one moving shift element may include an array or plurality of protruding shift elements. InFIG.5Bthe plurality of protruding shift elements288are designated individually as288A,288B,288C,288D designating different orientations on the chainring structure.

The protruding shift elements288A288B,288C,288D,302of the array may be disposed at different radial distances D1, D2, D3, D4, D5from a rotational axis R of the structure. These distances may also be different relative to the larger and/or smaller sprockets. As illustrated, a first protruding shift element288A may be disposed between a root circle R1and a tooth tip circle R2of the smaller sprocket154. A second protruding shift element302may be disposed between the root circle and the tooth tip circle R4of the larger sprocket152. A plurality of protruding shift elements288B,288C,288D may be disposed radially and/or circumferentially between the first protruding shift element288A and the second protruding shift element302. The plurality of protruding shift elements may have each have a tip configured to engage the chain. The respective tips each disposed at different axial distances relative to the larger and smaller chain rings152,154.

The plurality of protruding shift elements may cause the chain to be shifted through a transition zone T between the smaller chain ring teeth and the larger chain ring teeth. For example, the transition zone may be defined as the radial area between the tooth tip circle R2and the larger chain ring root circle R3. A plurality of protruding shift elements288B,288C,288D may be disposed in the transition zone T.

Exchanging, or shifting, a change between two or more sprockets may be accomplished from a larger sprocket152to a smaller sprocket154using downshifting element, which may be formed as a slide or slanted planar surface that may be moved into, and/or out of, the chainline at the larger sprocket to cause the chain to slide or shift towards the smaller sprocket. The downshifting elements may be disposed outside of the transition zone T, but cause the chain to move through the transition zone T.

In the disclosed examples, the front shift unit is generally described as including the chain ring unit, including the big and small chain rings, and the front shift mechanism, including all of the various shift components. However, more or fewer of the parts and components of the bicycle may be included or considered as a part of the so-called front shift unit within the scope of the present disclosure. Further, the front shifting system is generally described herein as including the front shift unit, the shifter, the chain, and the crank assembly components. Again, more or fewer of the parts and components of the bicycle may be included or considered as a part of the so-called front shifting system within the scope of present disclosure. In the disclosed example, the drive wheel that is driven by the drive train is the rear wheel, though the disclosure is not limited thereto.

In one example, according to the teachings of the present disclosure, a bicycle includes a frame, wheels for supporting the frame on a surface, a drive train operable to drive rotation of a drive wheel of the wheels, the drive train including a cassette carried adjacent the drive wheel and a chain coupled to the cassette. A front shifting assembly is carried on the bicycle and includes a shifter operable to transmit a wireless signal and a crank assembly having two crank arms and a pedal associated with 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 for rotation therewith about the rotation axis. The front shift unit has a chain ring component and a shift mechanism coupled to the chain ring component. The chain ring component has 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. The chain extends between the cassette and the chain ring component. The shift mechanism is configured to receive the wireless signal from the shifter and to shift the chain between the big chain ring and the small chain ring according to the wireless signal.

In one example, the shift mechanism can be on the big chain ring.

In one example, the shift mechanism can include at least one upshift element movable relative to the front shift unit to selectively engage the chain to execute an upshift of the chain from the small chain ring to the big chain ring.

In one example, at least one upshift element of the shift mechanism can be mounted to the big chain ring.

In one example, the shift mechanism can include at least one downshift element movable relative to the front shift unit to selectively engage the chain to execute a downshift of the chain from the big chain ring to the small chain ring.

In one example, at least one downshift element of the shift mechanism can be mounted to the big chain ring.

In one example, the shift mechanism can include a first downshift element and a second downshift element. The second downshift element can be positioned opposite or 180 degrees offset relative to the first downshift element around a circumference of the chain ring component.

In one example, the shift mechanism can include at least one downshift element movable relative to the chain ring component to selectively engage the chain to execute a downshift of the chain from the big chain ring to the small chain ring.

In one example according to the teachings of the present disclosure, a front shift unit for a bicycle includes a chain ring component having a big chain ring and a small chain ring joined for co-rotation with one another about a rotation axis. The big chain ring has a big diameter and a plurality of big ring sprocket teeth and the small chain ring has a small diameter and a plurality of small ring sprocket teeth. The big diameter is larger than the small diameter. The front shift unit also includes a shift mechanism coupled to the chain ring component. The shift mechanism includes an electronic control unit, a gearmotor unit, at least one upshift element, at least one downshift element, and a power supply. The power supply is arranged to provide power for the electronic control unit and the gearmotor 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 is operable by the electronic control unit and the gearmotor unit to shift a chain from the plurality of small ring sprocket teeth on the small chain ring to the plurality of big ring sprocket teeth on the big chain ring. According to a wireless downshift signal, the at least one downshift element is operable by the electronic control unit and the gearmotor unit to shift a chain from the plurality of big ring sprocket teeth on the big chain ring to the plurality of small ring sprocket teeth on the small chain ring.

In one example, the chain ring component can be formed as one integrated component from the same material.

In one example, each of the electronic control unit, the gearmotor unit, the at least one upshift element, the at least one downshift element, and the power supply can be carried on the big chain ring of the chain ring component.

In one example, each of the electronic control unit, the gearmotor unit, the at least one upshift element, the at least one downshift element, and the power supply can be carried on an outboard surface of the big chain ring.

In one example, the at least one downshift element can include a first downshift element and a second downshift element positioned opposite the first downshift element around a circumference of the chain ring component

In one example, a first downshift element of the shift mechanism and an upshift element of the shift mechanism can be operable by a first link coupled to the gearmotor unit.

In one example, the shift mechanism can include a first cam shaft coupled to the gearmotor unit and rotatable about a first cam axis. An upshift driver can be rotatable about the first cam axis and configured to move an upshift element of the shift mechanism between an upshift state capable of engaging a chain on the small ring sprocket teeth of the small chain ring and a neutral state not capable of engaging a chain on the chain ring component. A first downshift driver can be rotatable about the first cam axis and configured to move a first downshift element of the shift mechanism between a downshift state capable of engaging a chain on the big ring sprocket teeth of the big chain ring and a neutral state not capable of engaging a chain on the chain ring component.

In one example, when an upshift element of the shift mechanism moves to an upshift state to engage a chain, a first downshift element of the shift mechanism can be in a neutral state to not engage the chain. When the first downshift element moves to a downshift state to engage the chain, the upshift element can be in a neutral state to not engage the chain.

In one example, the shift mechanism can include a second cam shaft coupled to the gearmotor unit and rotatable about a second cam axis. A second downshift driver can be rotatable about the second cam axis and configured to move a second downshift element of the shift mechanism between a downshift state capable of engaging a chain on the big ring sprocket teeth of the big chain ring and a neutral state not capable of engaging a chain on the chain ring component.

In one example, when an upshift element of the shift mechanism moves to an upshift state to engage a chain, a first downshift element and a second downshift element of the shift mechanism can be in a neutral state to not engage the chain. When the first and second downshift elements move to a downshift state to engage the chain, the upshift element can be in the neutral state to not engage the chain.

In one example, a first downshift element and a second downshift element of the shift mechanism can move in concert with one another between a downshift state and a neutral state.

In one example, a second downshift element of the shift mechanism can be operable by a second link coupled to the gearmotor unit.

In one example according to the teachings of the present disclosure, a front shifting system for a bicycle includes a shifter mountable on the bicycle. The shifter is operable to transmit a wireless signal. The front shifting system includes a crank assembly having two crank arms and a pedal associated with each of the two crank arms. The crank assembly is rotatable about a rotation axis. The front shifting system includes a chain and a front shift unit coupled to the crank assembly and 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. The front shift unit also includes a shift mechanism 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 the chain between the big chain ring and the small chain ring according to the wireless signal.

In one example, the shifter can be mountable on a bicycle remote from the front shift unit.

In one example, the shift mechanism can include an electronic control unit, a gearmotor unit in communication with the electronic control unit, at least one upshift element coupled to the gearmotor unit, at least one downshift element coupled to the gearmotor unit, and a power supply arranged to provide power for the electronic control unit and the gearmotor unit to operate the at least one upshift element and the at least one downshift element.

In one example, according to a wireless upshift signal received by the electronic control unit, the at least one upshift element can be operable by the gearmotor unit to shift the chain from the small chain ring to the big chain ring. According to a wireless downshift signal received by the electronic control unit, the at least one downshift element can be operable by the gearmotor unit to shift the chain from the big chain ring to the small chain ring.

In one example, each of the electronic control unit, the gearmotor unit, the at least one upshift element, the at least one downshift element, and the power supply can be carried on the big chain ring of the chain ring component.

In one example, at least one downshift element of the shift mechanism can include a first downshift element and a second downshift element, which can be positioned opposite the first downshift element around a circumference of the chain ring component.

In one example, a first downshift element and an upshift element of the shift mechanism can be operable by a first link coupled to the gearmotor unit.

In one example, a second downshift element of the shift mechanism can be operable by a second link coupled to the gearmotor unit.

In one example, the shift mechanism can include a first cam shaft coupled to the gearmotor unit and rotatable about a first cam axis. The shift mechanism can also include an upshift driver rotatable about the first cam axis and configured to move an upshift element of the shift mechanism between an upshift state engaging the chain on the small chain ring and a neutral state not engaging the chain on the chain ring component. The shift mechanism can also include a first downshift driver rotatable about the first cam axis and configured to move a first downshift element of the shift mechanism between a downshift state engaging the chain on the big chain ring and a neutral state not engaging the chain on the chain ring component.

In one example, when an upshift element of the shift mechanism moves to an upshift state, a first downshift element can be in a neutral state. When the first downshift element moves to a downshift state, the upshift element can be in the neutral state.

In one example, the shift mechanism can include a second cam shaft coupled to the gearmotor unit and rotatable about a second cam axis. The shift mechanism can also include a second downshift driver rotatable about the second cam axis and configured to move a second downshift element of the shift mechanism between a downshift state engaging the chain on the big chain ring and a neutral state not engaging the chain on the chain ring component.

In one example, when an upshift element of the shift mechanism moves to an upshift state, a first downshift element and a second downshift element of the shift mechanism can be in a neutral state. When the first and second downshift elements move to a downshift state, the upshift element can be in the neutral state.

In one example, first and second downshift elements of the shift mechanism can move in concert with one another between a downshift state and a neutral state.

In one example, the chain ring component can be formed as one integral structure including the big chain ring and the small chain ring.

In one example according to the teachings of the present disclosure, a method of mounting a front shift system on a bicycle includes mounting a shifter to a portion of the bicycle. The shifter is operable to transmit a wireless signal. A crank assembly rotatable about a rotation axis is attached to a frame of the bicycle. The crank assembly has two crank arms, a pedal associated with each of the two crank arms, and a front shift unit coupled to the crank assembly for rotation therewith about the rotation axis. The front shift unit has a chain ring component and a shift mechanism carried by the chain ring component. A chain is connected between the chain ring component and a rear cassette of the bicycle. The shifter is paired with an electronic control unit of the shift mechanism carried by the chain ring component.

In another example a bicycle front shifting assembly is presented. The front shifting assembly includes a front shift unit configured to be coupled to a crank assembly for rotation therewith about a rotation axis, the front shift unit having a chain ring component and a shift mechanism coupled to the chain ring component. The chain ring component has a big chain ring having a plurality of teeth defining a big chainring plane and a small chain ring having a plurality of teeth defining a small chainring plane, the small chain ring having a small diameter and the big chain ring having a big diameter that is larger than the small diameter. The shift mechanism includes at least one protruding shift element disposed in a transition zone between the big chain ring and the small chain ring, the shift mechanism configured to move the at least one protruding shift element axially between the big chainring plane and the small chainring plane. The shift mechanism may include a plurality of protruding shift elements disposed in the transition zone. The plurality of protruding shift elements may be upshift elements. The shift mechanism may include an upshift element configured to move axially to intersect the small chain ring plane. The upshift element configured to move axially to intersect the small chain ring plane may be disposed radially between a root circle and a tooth tip circle of the small chain ring. The shift mechanism may further include at least one downshift element movable relative to the front shift unit to selectively engage the chain to execute a downshift of a chain from the big chain ring to the small chain ring. The at least one downshift element may include a first downshift element and a second downshift element. The second downshift element may be positioned opposite the first downshift element around a circumference of the chain ring component. The front shift unit may further comprise an electric motor rotating fixed to the chain ring component, the electric motor configured to cause the at least one protruding shift element to move axially. The shift mechanism may further include at least one downshift element movable relative to the front shift unit to selectively engage the chain to execute a downshift of a chain from the big chain ring to the small chain ring, and the electric motor is configured to also cause the downshift element to move.

In another example, a front shift unit for a bicycle is provided. The front shift unit includes a chain ring component having a big chain ring and a small chain ring joined for co-rotation with one another about a rotation axis, the big chain ring having a big diameter and a plurality of big ring sprocket teeth and the small chain ring having a small diameter and a plurality of small ring sprocket teeth, the big diameter being larger than the small diameter. The front shift unit also includes a shift mechanism coupled to the chain ring component, the shift mechanism including an electronic control unit, a gearmotor unit, at least one upshift element, at least one downshift element, and a power supply arranged to provide power for the electronic control unit and the gearmotor unit to operate the at least one upshift element and the at least one downshift element. The at least one upshift element is disposed in a transition zone between the small chain ring teeth and the big chain ring teeth and axially movable by the electronic control unit and the gearmotor unit to shift a chain from the plurality of small ring sprocket teeth on the small chain ring to the plurality of big ring sprocket teeth on the big chain ring. The at least one downshift element is operable by the electronic control unit and the gearmotor unit to shift a chain from the plurality of big ring sprocket teeth on the big chain ring to the plurality of small ring sprocket teeth on the small chain ring. The chain ring component may be formed as one integrated component from the same material. The at least one upshift element may include a plurality of upshift elements. Each of the electronic control unit, the gearmotor unit, the at least one upshift element, the at least one downshift element, and the power supply may be carried on an outboard surface of the big chain ring. The at least one downshift element includes a first downshift element and a second downshift element positioned opposite the first downshift element around a circumference of the chain ring component. The first downshift element and the upshift element may be operable by a first link coupled to the gearmotor unit.

The shift mechanism may further include a first cam shaft coupled to the gearmotor unit and rotatable about a first cam axis, an upshift driver rotatable about the first cam axis and configured to move the upshift element between an upshift state capable of engaging a chain on the small ring sprocket teeth of the small chain ring and a neutral state not capable of engaging a chain on the chain ring component, and a first downshift driver rotatable about the first cam axis and configured to move the first downshift element between a downshift state capable of engaging a chain on the big ring sprocket teeth of the big chain ring and a neutral state not capable of engaging a chain on the chain ring component. The upshift element may move 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. The shift mechanism may further include a second cam shaft coupled to the gearmotor 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 the downshift state capable of engaging a chain on the big ring sprocket teeth of the big chain ring and the neutral state not capable of engaging a chain on the chain ring component. The at least one upshift element may include a plurality of upshift elements and the plurality of upshift elements move in concert with one another to achieve the upshift state.

Although certain front shifting system examples, front shift unit examples, shifting mechanisms, parts, and/or components of same, and shifting methods have been described herein in accordance with the teachings of the present disclosure, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all embodiments of the teachings of the disclosure that fairly fall within the scope of permissible equivalents.

The illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The illustrations are not intended to serve as a complete description of all of the elements and features of apparatus and systems that utilize the structures or methods described herein. Many other embodiments may be apparent to those of skill in the art upon reviewing the disclosure. Other embodiments may be utilized and derived from the disclosure, such that structural and logical substitutions and changes may be made without departing from the scope of the disclosure. Additionally, the illustrations are merely representational and may not be drawn to scale. Certain proportions within the illustrations may be exaggerated, while other proportions may be minimized. Accordingly, the disclosure and the figures are to be regarded as illustrative rather than restrictive.

While this specification contains many specifics, these should not be construed as limitations on the scope of the invention or of what may be claimed, but rather as descriptions of features specific to particular embodiments of the invention. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable sub-combination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a sub-combination or variation of a sub-combination.

Similarly, while operations and/or acts are depicted in the drawings and described herein in a particular order, this depiction should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments.

One or more embodiments of the disclosure may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any particular invention or inventive concept. Moreover, although specific embodiments have been illustrated and described herein, it should be appreciated that any subsequent arrangement designed to achieve the same or similar purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all subsequent adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, are apparent to those of skill in the art upon reviewing the description.

The Abstract of the Disclosure is provided with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, various features may be grouped together or described in a single embodiment for the purpose of streamlining the disclosure. This disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter may be directed to fewer than all of the features of any of the disclosed embodiments. Thus, the following claims are incorporated into the Detailed Description, with each claim standing on its own as defining separately claimed subject matter.

It is intended that the foregoing detailed description be regarded as illustrative rather than limiting and that it is understood that the following claims including all equivalents are intended to define the scope of the invention. The claims should not be read as limited to the described order or elements unless stated to that effect. Therefore, all embodiments that come within the scope and spirit of the following claims and equivalents thereto are claimed as the invention.