Patent Description:
Most of the electromechanical gear changers and systems in existence are bulky, heavy, expensive, difficult to install, and unattractive. One reason is that they communicate and are powered by wires. As a result, the manufacturers of these devices must produce and stock many different lengths of cables for the many different sizes/styles of bike frames available.

From <CIT>, a motorized bicycle derailleur assembly is known which has a motor unit for moving a motor linkage connected to a chain guide. A battery is located on a front side of the bicycle derailleur assembly. Document <CIT> shows the preamble of claim <NUM>.

There is a need for an electromechanical gear changer that is lightweight, effective, compact, and easy to install. The invention satisfies the need.

The invention relates to an electromechanical front gear changer according to claim <NUM>. The invention also relates to an electromechanical gear changer according to claim <NUM>. The dependent claims relate to embodiments of the invention.

One aspect of the invention provides an electromechanical front gear changer for a bicycle, in particular an electromechanical front gear changer for a bicycle having a chain, comprising:.

According to the first aspect, the invention provides that the electromechanical front gear changer, further comprising:
a receiver for receiving wireless signals and powered by the power supply, wherein the CPU is in operative with communication with the receiver and processes the received wireless signals.

According to the first aspect, the invention provides that the electromechanical front gear changer, further comprising a housing attached to the base member.

According to the first aspect, the invention provides that the motor, the gear transmission, receiver, and CPU are positioned within the housing.

According to the first aspect, the invention provides that the housing is formed of a material permitting the passage of wireless signals therethrough.

According to the first aspect, the invention may further provide that the housing is made of plastic.

According to the first aspect, the invention provides that the housing has a front housing portion positioned at or near a front of the front gear changer and a rear housing portion positioned behind the front housing portion.

According to the first aspect, the invention provides that the receiver is positioned in or proximate the front housing portion.

According to the first aspect, the invention provides that the power supply is removably coupled to the rear housing portion.

According to a not claimed second aspect, the application provides that an electromechanical front gear changer for a bicycle having a chain, comprising:.

According to the second aspect of the application, it may be further provided that the pair of spaced apart points include a first tab and a second tab of the base member.

According to the second aspect of the application, it may be further provided that the output arm is positioned between the first tab and the second tab.

According to the second aspect of the application, it may be further provided that the first tab is positioned at or near the front of the base member and the second tab is positioned at or near the rear of the base member.

According to the second aspect of the application, it may be further provided that the outer link is pivotally disposed about the first link pin.

According to the second aspect of the application, it may be further provided that the first link pin extends between the first tab and the second tab.

According to the second aspect of the application, it may be further provided that the electromechanical front gear changer further comprising a housing attached to the base member the gear transmission disposed in the housing.

According to the second aspect of the application, it may be further provided that the electromechanical front gear changer further comprising a first biasing element disposed about the first link pin and biasing the output arm against the outer link.

According to the second aspect of the application, it may be further provided that the output arm is urged toward the outer link by the transmission when the output arm is moved in a first direction and is urged by the transmission toward the first biasing element when the output arm is moved in a second direction.

According to the second aspect of the application, it may be further provided that the first direction is an outboard direction and the second direction is an inboard direction.

According to the second aspect of the application, it may be further provided that the gear transmission includes a sector gear which receives a torque input from the motor and includes a tubular portion rotatably disposed about the first link pin and connected to the output arm.

According to the second aspect of the application, it may be further provided that the outer link includes a pair of spaced ends interleaved with the pair of spaced apart points of the base member and wherein the output arm and the tubular portion of the sector gear are positioned therebetween.

According to the second aspect of the application, it may be further provided that the electromechanical front gear changer further comprising a second biasing element that biases the chain guide into an inboard position.

According to a third aspect, the invention provides an electromechanical gear changer for a bicycle having a chain, comprising:.

According to the third aspect, the invention may further provide that the electromechanical gear changer further comprising a latching mechanism for the removable coupling of the power supply housing to the rear housing portion.

According to the third aspect, the invention may further provide that the latching mechanism includes a latch movably mounted on one of the power supply housing and the housing.

According to the third aspect, the invention may further provide that the latching mechanism includes a catch disposed on the other of the power supply housing and the housing positioned to cooperate with the latch.

According to the third aspect, the invention may further provide that the electromechanical gear changer further comprising electrical contacts on the rear housing portion.

According to the third aspect, the invention may further provide that the electromechanical gear changer further comprising terminals disposed on the power supply housing and positioned to contact the electrical contacts for electrical connection therebetween.

According to the third aspect, the invention may further provide that the contacts are biased pins.

According to the third aspect, the invention may further provide that the electromechanical gear changer further comprising a printed circuit board positioned within the housing and attached to the rear housing portion, and wherein the contacts are mounted directly on the printed circuit board and extend to the outside of the rear housing portion.

According to the third aspect, the invention may further provide that the electromechanical gear changer further comprising battery contact seals surrounding each of the contacts.

According to the third aspect, the invention may further provide that the electromechanical gear changer further comprising a battery face seal disposed on one of the power supply housing and the rear housing portion and wherein the battery face seals to the other of the power supply housing and the rear housing portion and surrounds the terminals and the contacts when the power supply housing is attached to the housing.

According to a not claimed fourth aspect, the application may further provide an electromechanical front gear changer for a bicycle having a chain, comprising:.

According to the fourth aspect, the application may further provide that the manually operated device is a button.

According to the fourth aspect, the application may further provide that the change of state enables a pairing of the front gear changer.

According to the fourth aspect, the application may further provide that the change of state includes changing the position of the chain guide.

According to the fourth aspect, the application may further provide that the change of position includes trimming the position of the chain guide.

According to the fourth aspect, the application may further provide that the change of position includes a gear shift.

Embodiments of the invention will herein be described with reference to the drawings. It will be understood that the drawings and descriptions set out herein are provided for illustration only and do not limit the invention as defined by the claims appended hereto and any and all their equivalents. For example, the terms "first" and "second," "front" and "rear," or "left" and "right" are used for the sake of clarity and not as terms of limitation. Moreover, the terms refer to bicycle mechanisms conventionally mounted to a bicycle and with the bicycle oriented and used in a standard fashion unless otherwise indicated.

Referring to <FIG>, an electromechanical front gear changer <NUM>, or front derailleur according to one embodiment of the invention, may be attached to a bicycle frame <NUM> by connecting base member <NUM> of the gear changer to a front gear changer hanger <NUM> of the frame in a conventional manner using a fixation bolt <NUM> and a fixation washer <NUM>. Alternatively, the base member <NUM> may include or be made attachable to a clamp, as is well known, for attaching the gear changer <NUM> to the bicycle frame <NUM>.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, the basic structure of the electromechanical front gear changer <NUM> includes a removable power supply, which may be in the form of a battery <NUM> enclosed with a power supply housing <NUM>, which is installed on a motor gearbox module <NUM> attached to the base member <NUM>. The motor gearbox module <NUM> may be considered to include or be enclosed at least in part within a housing <NUM>, which may include rear and front housing portions <NUM>, <NUM>. The rear and front housing portions <NUM>, <NUM> may be formed of a single or multiple pieces. The power supply housing <NUM> should present little, negligible, or no aerodynamic drag because of its position at the rear of the rear housing portion <NUM>. The physical shape and size (form factor) of the power supply housing <NUM> as viewed from the front (see front view of <FIG>) is less than that presented by the housing <NUM> and thus does not contribute to the frontal area of the gear changer <NUM>. In other words, one cannot see the power supply housing <NUM> from the front of the bicycle because its physical shape and size are less - when viewed from the front and looking backwards - than that presented by the housing <NUM> formed by housing portions <NUM>, <NUM>.

The base member <NUM> functions as one bar of what may be referred to as a four-bar linkage <NUM>. The linkage includes an outer link <NUM> and an inner link <NUM>, which are each pivotally connected to base member <NUM> and make up two more of the four bars in the linkage <NUM>. A cage assembly (also known as a chain guide) <NUM> completes the four-bar linkage <NUM> by pivotally connecting to inner link <NUM> and connected to outer link <NUM> in a manner that may allow both pivotal and axial motion. In one embodiment, this linkage geometry allows chain guide <NUM> to rotate relative to its own yaw axis <NUM> and to move relative to base member <NUM>. Other more conventional linkages are also contemplated. Bicycle chain <NUM> is engaged with chainrings <NUM> and chain guide <NUM> in a conventional manner and is shifted between the two rings by the movement of chain guide relative to base member <NUM>.

Referring to <FIG>, base member <NUM> may be rigidly connected to the motor gearbox module <NUM> according to the following arrangement. Motor module to bracket rear screw <NUM> is received in a counter-bore thru hole in base member <NUM> and is also threadably engaged with a corresponding blind hole in rear housing portion <NUM> in motor gearbox module <NUM>. Motor module to bracket front screw <NUM> is received in a second counter-bore thru hole in base member <NUM> and is threadably engaged with a corresponding blind hole in front housing portion <NUM> in motor gearbox module <NUM>.

Referring to <FIG>, the basic details of an example of a four-bar linkage structure <NUM> suitable for the present invention are as follows. It will be understood that while the example linkage set out herein exhibits a yaw motion as it moves, a standard linkage that does not exhibit motion in the yaw direction could be employed. The yaw type linkage reduces or eliminates the need to trim the position of the front derailleur to accommodate the derailleur to the chain line created by the position of the chain on one of the rear sprockets. If a non-yaw linkage is employed, the invention could incorporate a feature to trim the front derailleur in response to a sensed or calculated position of the chain guide, for example.

Referring to <FIG>, first link pin <NUM> is received in thru holes in base member front tab <NUM> and base member rear tab <NUM>, which are formed at two spaced apart points on the base member <NUM>. First link retaining ring <NUM> engages a groove in first link pin <NUM> and keeps first link pin from backing out of the thru holes. First link rear inner bushing <NUM> is received in the thru hole in outer link rear tab <NUM> and first link front inner bushing <NUM> is received in the thru hole in outer link front tab <NUM>. First link front inner bushing <NUM> and first link rear inner bushing <NUM> are pivotally connected to first link pin <NUM>. Thus, outer link <NUM> is pivotally connected to base member <NUM>.

Second link pin <NUM> is received in two thru holes in chain guide <NUM>. Second link retaining ring <NUM> engages a groove in second link pin <NUM> and keeps it from backing out of the thru holes. Outer link <NUM> is pivotally connected to second link pin <NUM> and also allows movement between it and the second link pin along its long axis. Thus, chain guide <NUM> is pivotally connected to outer link <NUM> and able to rotate relative to the yaw axis of outer link <NUM> (see <FIG>).

Referring to <FIG>, third link pin <NUM> may be slip-fit into a counterbore at the front end of base member <NUM> and received, by a press fit, in a thru hole at the rear of base member. Thus, third link pin <NUM> and base member <NUM> are rigidly connected. Third link front inner bushing <NUM> is received in a thru hole in inner link <NUM> and third link rear inner bushing <NUM> is received in a second thru hole in the inner link. Third link pin <NUM> is rotatably received in both third link front inner bushing <NUM> and third link rear inner bushing <NUM>. Thus, inner link <NUM> is pivotally connected to base member <NUM>. Fourth link pin <NUM> is received in two thru holes in chain guide <NUM> and prevented from backing out by fourth link retaining ring <NUM>, which engages in a groove in fourth link pin <NUM>. Fourth link front inner bushing <NUM> is received in a thru hole in inner link <NUM> and fourth link rear inner bushing <NUM> is received in another thru hole in inner link. Fourth link pin <NUM> is rotatably received in both fourth link front inner bushing <NUM> and fourth link rear inner bushing <NUM>. Thus, inner link <NUM> is pivotally connected to chain guide <NUM> to complete the four-bar linkage. It will be understood that the illustrated linkage <NUM> is only one example of a number of link configurations that would be suitable for the inventive gear changer set out herein.

Referring to <FIG>, <FIG>, and <FIG>, first link pin <NUM> is also rotatably received in motor gearbox module output arm <NUM>, sector gear <NUM>, and saver spring bushing <NUM>. Motor gearbox module output arm <NUM> and a rear tubular portion of sector gear <NUM> may be rigidly coupled by press fit of complementary castellation features or any suitable structure or technique. Thus, any torque on sector gear <NUM> about the long axis of first link pin <NUM> gets transferred to motor gearbox module output arm <NUM> about the same axis. Sector gear <NUM>, motor gearbox module output arm <NUM>, a first biasing element <NUM>, e.g., a saver spring, and saver spring bushing <NUM> are captured at a position between portions of the outer link <NUM> and/or the base member <NUM>, e.g., front tab <NUM> and outer link rear tab <NUM>. An outer face <NUM> of motor gearbox module output arm <NUM> engages with upper limit set screw <NUM>, which is threadably engaged with outer link <NUM>. Thus, a torque on motor gearbox module output arm <NUM> in the direction outboard of the center plane of bicycle frame <NUM> (clockwise direction in <FIG>) will translate into an outboard torque on the outer link <NUM>. The user can set the amount of angular offset between outer link <NUM> and motor gearbox module output arm <NUM> by changing how deeply the upper limit set screw <NUM> is positioned in the outer link.

Saver spring bushing <NUM> is received in the inner diameter of first biasing element <NUM>, for example a helical torsion spring, and thus first biasing element is able to rotate along the long axis of first link pin <NUM>. One leg <NUM> at the front of saver spring <NUM> engages an inner wall <NUM> of motor gearbox module output arm <NUM> and urges it clockwise as shown in <FIG>. A second leg <NUM> on the opposite end of saver spring <NUM> engages an internal wall <NUM> of outer link <NUM> and urges it in the counterclockwise direction in <FIG>, which biases upper limit set screw <NUM> against motor gearbox module output arm <NUM> with a preload force determined by the angular offset between the two parts. Thus, a torque on motor gearbox module output arm <NUM> in the inboard direction as shown in <FIG> will translate into a torque in the inboard direction on the outer link <NUM> through saver spring <NUM>.

If an external force greater than the preload force from first biasing element <NUM> acts upon outer link <NUM> to prevent it from rotating inboard, a situation seen when electromechanical front gear changer <NUM> attempts to downshift chain <NUM> under extremely high chain tension or with chainrings <NUM> stationary relative to chain, saver spring deflects angularly to allow motor gearbox module output arm <NUM> to rotate inboard. This prevents a motor stall condition inside motor gearbox module <NUM>, which causes extra stress on the torque transferring components, i.e., parts of the transmission <NUM> inside motor gearbox module, and wastes energy from the power supply <NUM>.

Referring to <FIG>, <FIG>, <FIG>, and <FIG>, second biasing element <NUM>, for example a helical torsion spring, urges the four-bar linkage in the inboard direction to eliminate play from the four-bar linkage through to stage three worm <NUM>. Bias spring front bushing <NUM> and bias spring rear bushing <NUM> are received in either end of second biasing element <NUM> and fourth link pin <NUM> is received in both bushings. Thus, second biasing element <NUM> and fourth link pin <NUM> are pivotally connected. One end of second biasing element <NUM> engages chain guide <NUM> and urges it clockwise as shown in <FIG>. The other end of second biasing element <NUM> engages an inner wall <NUM> of inner link <NUM> and urges it counterclockwise as shown in <FIG>. In <FIG>, second biasing element <NUM> has urged the four-bar linkage to its extreme inboard configuration, i.e. toward the bicycle frame. The inboard travel of the four-bar linkage <NUM> is limited when lower limit set screw <NUM> contacts an inner wall of base member <NUM>. Because lower limit set screw <NUM> is threadably engaged with outer link <NUM>, this acts as a limit of travel between outer link <NUM> and base member <NUM>. The user can adjust this limit of travel by adjusting how deeply the lower limit set screw <NUM> is positioned in the threaded hole in outer link <NUM>.

Referring to <FIG>, battery <NUM> may be rechargeable and may be of the lithiumpolymer variety. Terminals <NUM> may be recessed slightly below a front surface of power supply housing <NUM> and may be co-molded into the power supply housing. Catch <NUM> may be formed and located on a top surface of power supply housing <NUM> and projections <NUM> are located on a bottom surface of the battery housing.

Referring to <FIG>, <FIG>, and <NUM>, battery contact pins <NUM> are received in battery contact seals <NUM>, which are received in thru holes in rear housing portion <NUM> of motor gearbox module <NUM>. Battery contact seals <NUM> may be made of an elastomeric silicone material and function to form water-tight seals between battery contact pins <NUM> and rear housing portion <NUM>. Battery contact pins <NUM> are electrically connected to the internal circuitry of PC (printed circuit) board assembly <NUM> and may be rigidly mounted directly to the surface of PC board assembly. The tips of battery contact pins <NUM> may be spring-loaded in the direction along their long axis to ensure reliable electrical connection with the terminals <NUM>. Battery face seal <NUM> has a lip along its entire perimeter that is either pressed or glued into a blind groove in rear housing portion <NUM> to hold it in place. Battery latch pin <NUM> may be received in two thru holes in rear housing portion <NUM> and latch pin retaining ring <NUM> engages a groove in the battery latch pin to prevent it from backing out. Battery latch <NUM> rotatably receives battery latch pin <NUM> in one thru hole between the two thru holes in rear housing portion <NUM>. The battery latch pin <NUM> could be press-fit into the rear housing portion <NUM>. Battery latch <NUM> may be pivotally connected to rear housing portion <NUM>. In the alternative, the latch <NUM> could be connected to the power supply housing <NUM> and connect to a feature provided on housing portion <NUM> or <NUM>.

<FIG> shows power supply housing <NUM> installed on motor gearbox module <NUM>. Battery latch <NUM> has a hooked end <NUM> that engages catch <NUM> of power supply housing <NUM> and prevents power supply housing travel to the left as shown in <FIG>. The hooked end <NUM> and catch <NUM> also prevent battery latch <NUM> from rotating in a clockwise direction as shown in <FIG> as long as there is no large external force that uncouples the hook and catch. Projections <NUM> of battery <NUM> are engaged in corresponding battery engaging holes in rear housing portion <NUM>. Power supply housing <NUM> is held in an installed position that forces battery seal <NUM> to deform slightly, forming a water-tight seal. The deformation of battery seal <NUM> also causes the battery seal to exert an urging force against the front surface of power supply housing <NUM>, urging the surface to the left in <FIG>. This urging force, in turn, causes catch <NUM> of power supply housing <NUM> to be urged to the left, against hook <NUM> of battery latch <NUM> and causes projections <NUM> of the power supply housing to be urged to the left, against battery engaging holes. In this manner, any play between power supply housing <NUM> and rear housing portion <NUM> is eliminated and the power supply housing is positively retained in motor gearbox module <NUM>. The installed position of power supply housing <NUM> also forces battery contact pins <NUM> to compress their internal springs against battery terminals <NUM>, creating a pressure contact between battery contact pins and battery terminals that ensures reliable conduction of electricity.

<FIG> show a process by which the user can easily remove power supply housing <NUM>. Referring to <FIG>, the user pulls the end of battery latch <NUM> upwards to begin the latch clockwise. Battery latch hook <NUM> and battery catch <NUM> have a ramped mating interface such that, with sufficient force from the user, battery latch hook <NUM> urges the battery catch and thus the entire power supply housing <NUM> to the right against the urging force from battery face seal <NUM>. Once battery latch hook <NUM> slides past the tip of battery catch <NUM>, battery latch <NUM> is free to rotate clockwise about battery latch pin <NUM> and battery <NUM> is free to pivot counterclockwise around the engagement point of projections <NUM> and battery engaging holes on rear housing portion <NUM>.

Referring now to <FIG>, when power supply housing <NUM> has been rotated sufficiently counterclockwise, the user is able to lift power supply housing in a generally upwards motion, causing projections <NUM> of battery <NUM> to disengage from battery engaging holes of rear housing portion <NUM>. In this manner, power supply housing <NUM> is removed from motor gearbox module <NUM>. By reversing this process, the user is able to easily reinstall power supply housing <NUM>.

Referring to <FIG> and <FIG>, if formed as multiple pieces, the front housing portion <NUM> and the rear housing portion <NUM> may be clamped together by a plurality of (e.g., four (<NUM>)) outer housing screws <NUM>. For example, three outer housing screws <NUM> are received in clearance thru holes in front housing portion <NUM> and threadably engaged with rear housing portion <NUM>. One outer housing screw <NUM> is received in a clearance thru hole in rear housing portion <NUM> and threadably engaged with front housing portion <NUM>. Housing gasket <NUM> may be made of an elastomeric silicone material and sits in a groove on the mating surface of front housing portion <NUM>. Housing gasket <NUM> is compressed by a protrusion on rear housing portion <NUM> to form a water-tight seal along the outer perimeter between front housing portion <NUM> and rear housing portion. While the front housing portion <NUM> and rear housing portion <NUM> are shown as separate pieces, they may be considered to be made as a single piece or multiple pieces.

Referring to <FIG> and <FIG>, sector gear <NUM> has a rear tubular portion that extends through the inner diameters of sector gear rear bushing <NUM> and sector gear rear O-ring <NUM> and also through a thru hole in rear housing portion <NUM>. Sector gear rear O-ring <NUM> may be made of an elastomeric rubber material and forms a water-tight seal between sector gear <NUM> and rear housing portion <NUM>. A front tubular portion of sector gear <NUM> extends through the inner diameters of sector gear front bushing <NUM> and sector gear front O-ring <NUM> and also through a thru hole in front housing portion <NUM>. Sector gear front O-ring <NUM> may be made of an elastomeric rubber material and forms a water-tight seal between sector gear <NUM> and front housing portion <NUM>.

Referring to <FIG>, LED lens <NUM> is press fit into a thru hole in front housing portion <NUM> directly adjacent to a light emitting diode, LED <NUM>, mounted on front board <NUM> of PC board assembly <NUM>. This allows light emitted by the LED to travel through front housing portion <NUM> to be viewable by a user. A manually operated device, such as button <NUM>, is also mounted on the front board <NUM> of PC board assembly <NUM> and may be a momentary electrical switch. Button plunger <NUM> is a body of revolution that is received in a thru hole in front housing portion <NUM>. Button plunger O-ring <NUM> sits in an O-ring gland of button plunger <NUM> and forms a water-tight seal between button plunger and front housing portion <NUM>. When button plunger <NUM> is pressed by the user, it moves axially until it actuates button <NUM>, changing its switching state. When button plunger <NUM> is released by the user, the internally spring-loaded button <NUM> urges button plunger <NUM> axially away from the button, which reverts to its original switching state. Button <NUM> may be used to change a state of the front gear changer <NUM>. One example of a change of state includes the initiation or enablement of the process of wirelessly pairing the electromechanical front gear changer assembly <NUM> with its shifters (see <FIG>). Another example might be actuating the electromechanical front gear changer assembly <NUM> independent of a signal from the shifters for easier servicing or other functions. The actuation via the button <NUM> might change the position of the chain guide <NUM>, such as to permit or check the alignment thereof, to switch gears, or enable a trim function, for example. In the alternative, the front housing portion <NUM> may include a co-molded elastomeric material shaped and sized to receive the plunger <NUM>, or provided by way of some other method, such that the over-molded material can serve as a waterproof seal for the plunger.

Referring to <FIG> and <FIG>, motor gearbox inner assembly <NUM> is enclosed inside the cavity created when front housing portion <NUM> and rear housing portion <NUM> are clamped together. The main structural part of motor gearbox inner assembly <NUM> is main inner housing <NUM>, which includes features that align and fix the motor gearbox inner assembly to front housing portion <NUM> and rear housing portion <NUM>. On front housing portion <NUM>, inboard alignment hole <NUM> and outboard alignment hole <NUM> mate with front inboard alignment boss <NUM> and front outboard alignment boss <NUM>, respectively, on main inner housing <NUM>. On rear housing portion <NUM>, inboard alignment boss <NUM> and outboard alignment hole <NUM> mate with rear inboard alignment hole <NUM> and rear outboard alignment boss <NUM>, respectively, on main inner housing <NUM>. Each alignment boss may be tapered along its long axis so the respective engagement with its complement alignment hole begins as a slip-fit and end as a press-fit. Alternatively, all slip-fit connections may be provided with the optional addition of providing a foam lined interior to constitute a "spring element" to one or both of the front and rear housing portions <NUM>, <NUM> to cushion the components held inside and control axial movement thereof along the guide pins. Thus, main inner housing <NUM> is held connected to the rest of motor gearbox module <NUM>.

Referring to <FIG>, <FIG>, and <FIG>, PC board assembly <NUM> may be a rigid-flex PCB comprised of two flat rigid sections, front board <NUM> and rear board <NUM> and two flexible sections, flex circuit <NUM> and motor terminal flex circuit <NUM>, which extend directly from the sides of the rigid sections to eliminate the need for connectors. Front PCB mounting screw <NUM> is received in a clearance thru hole on front board <NUM> and threadably engages main inner housing <NUM> to fix front board against the front face of main inner housing in an orientation such that flex circuit <NUM> extends outboard. Flex circuit <NUM> is bent <NUM>° rearward immediately after extending past the side of front board <NUM>, runs along the length of motor gearbox inner assembly <NUM> and again bends <NUM>° inboard. Flex circuit <NUM> then immediately terminates into the side of rear board <NUM>. Rear outboard alignment boss <NUM> on main inner housing <NUM> is received in rear outboard alignment hole <NUM> and rear PCB alignment boss <NUM> is received in rear inboard alignment hole <NUM> to orient rear board <NUM> relative to the main inner housing. Rear PCB mounting screw <NUM> is received in a clearance thru hole in rear board <NUM> and threadably engages main inner housing <NUM> to fix rear board <NUM> against the rear face of main inner housing <NUM>.

Referring to <FIG>, motor terminal flex circuit <NUM> extends from the bottom side edge of rear board <NUM> and bends forward until positive motor terminal <NUM> and negative motor terminal <NUM> of motor <NUM> are received in clearance thru holes in motor terminal flex circuit <NUM>. The surface of motor terminal flex circuit <NUM> immediately surrounding the clearance thru holes are solder pads that create a continuous electrically conductive pathway between the terminals in motor <NUM> and the circuits in PC board assembly <NUM> when solder is applied in a conventional manner between the pads and terminals.

Referring to <FIG> and <FIG>, motor <NUM> is rigidly fixed to main inner housing <NUM> by two motor screws <NUM> that are received in clearance thru holes in main inner housing and threadably engaged to blind holes on the motor. The two threaded holes on motor <NUM> may be spaced <NUM>° apart, for example, on its bolt circle diameter so that the motor can be installed in one orientation relative to main inner housing <NUM>. This prevents any ambiguity regarding the locations of positive motor terminal <NUM> and negative motor terminal <NUM> in the assembly. Gear train or transmission <NUM>, some or all of which is located and supported by the main inner housing <NUM>, includes stage one pinion <NUM> fixed to the output shaft of motor <NUM> either by press fit or an adhesive. Stage one gear <NUM> and stage two pinion <NUM> are press fit together in a conventional manner that is well known in the gear making industry and are located in main inner housing <NUM> such that stage one gear <NUM> is meshed with stage one pinion <NUM>. A thru hole extends through wall of main inner housing <NUM> above stage one gear <NUM> and a blind hole extends through a wall of the main inner housing below stage two pinion <NUM>. Both holes are concentric with the center bore of stage two pinion <NUM>. Second gear axle <NUM> is press fit in the thru hole in main inner housing <NUM> and is rotatably received in the thru hole in stage two pinion <NUM>. A distal end of second gear axle <NUM> is press fit into the blind hole main inner housing <NUM>. The assembly of stage one gear <NUM> and stage two pinion <NUM> can rotate about second gear axle <NUM> but its translational location relative to the rest of motor gearbox inner assembly is limited by the two walls on main inner housing <NUM>. Thus, torque from the output shaft of motor <NUM> is able to be transferred to stage two pinion <NUM>.

Referring to <FIG> and <FIG>, center bore of worm upper bearing <NUM> rotatably receives a shaft on one end of stage three worm <NUM>. Center bore of stage two gear <NUM> is press fit onto a portion of shaft of stage three worm <NUM> above worm upper bearing <NUM>, as shown in <FIG>, and thus torque is allowed to transfer between the two parts. The center bore of worm lower bearing <NUM> rotatably receives a shaft on the other end of stage three worm <NUM>. The outer diameters of worm upper bearing <NUM> and worm lower bearing <NUM> are press-fit into bores in main inner housing <NUM> and stage two gear <NUM> is located in such a manner that stage two gear <NUM> is meshed with stage two pinion <NUM>. Worm bottom thrust plate <NUM> may be made of an aluminum material and is either pressed or co-molded into a slot in main inner housing <NUM> immediately below stage three worm <NUM>. Worm top thrust plate <NUM> may be made of an aluminum material and its either press fit into a slot or co-molded in main inner housing <NUM>. A second end of worm top thrust plate <NUM> is clamped down by worm wheel cover <NUM> to rigidly fix the worm top thrust plate to main inner housing <NUM>. Worm bottom thrust plate <NUM> and worm top thrust plate <NUM> engage stage three worm on either end and limit its movement along is long axis. Thus, torque from stage two pinion <NUM> is able to be transferred to stage three worm <NUM>. Also, the worm wheel cover <NUM> and worm top thrust plate <NUM> may be made as a one-piece construction.

Referring to <FIG>, <FIG>, and <FIG>, a splined shaft <NUM> of stage four pinion <NUM> is press fit into the center bore of stage three worm wheel <NUM>, which is positioned in such a way to mesh with stage three worm <NUM>. Thus torque from stage three worm <NUM> is able to be transferred to stage four pinion <NUM>. In front of stage three worm wheel <NUM> as shown in <FIG>, the shaft of stage four pinion <NUM> is rotatably received in the center bore of front worm wheel bearing <NUM>. The shaft of stage four pinion <NUM> behind the gear teeth section as shown in <FIG> is rotatably received in the center bore of rear worm wheel bearing <NUM>. Front worm wheel bearing <NUM> and rear worm wheel bearing <NUM> are rotatably received in semicircular bearing cutouts <NUM> in main inner housing <NUM>. Worm wheel cover <NUM> has two corresponding semicircular cutouts <NUM> that also receive front worm wheel bearing <NUM> and rear worm wheel bearing <NUM>. Four worm wheel cover screws <NUM> are received in clearance thru holes in worm wheel cover <NUM> and threadably engaged with main inner housing <NUM> to rigidly fix worm wheel cover <NUM> to main inner housing <NUM>, completing the circular cutouts that position front worm wheel bearing <NUM> and rear worm wheel bearing <NUM>. The shaft at the end of stage four pinion <NUM> is press fit into the center bore of magnet holder <NUM> and magnet <NUM> is press fit into magnet holder <NUM>. Alternatively, the magnet <NUM> may be slip-fit into holder <NUM> with a suitable adhesive. Thus, stage four pinion <NUM>, stage three worm wheel <NUM>, magnet holder <NUM>, and magnet <NUM> are all rotatable together as a unit about the long axis of stage four pinion <NUM>. The exposed face of magnet <NUM> is parallel to the surface of rear board <NUM> and the center axis of magnet <NUM> is concentric with the center of a magnetic rotary encoder chip <NUM> mounted on the surface of rear board <NUM>. Sector gear <NUM> is positioned in such a way that it is meshed with stage four pinion <NUM> and torque is able to be transferred between the two parts. Thus, torque from motor <NUM> is able to be transferred to sector gear <NUM>.

The radio <NUM> (<FIG>) (e.g., any device or devices capable of wirelessly transmitting and/or receiving signals) of PC board assembly <NUM> periodically listens for wireless shift signals or other commands from the shift units (not shown). The radio <NUM> may be positioned on the front board <NUM> of PC board assembly <NUM>. It is believed that positioning the radio <NUM> in this position within the front housing portion <NUM> will maximize its ability to receive and resolve signals. In addition, the housing portions <NUM>, <NUM> may be made of a material that is relatively transparent to wireless signals, such as plastic. This is somewhat contrary to common practice, where derailleur parts are typically made of metal for its stiffness and strength.

When a wireless shift signal is received by the radio <NUM> of PC board assembly <NUM>, the radio forwards the shift signal to a processor (CPU <NUM>), and a PID control loop (proportional-integral-derivative controller) may be used to manage a flow of electrical power from power supply <NUM> through battery contact pins <NUM> and PC board assembly <NUM> to motor <NUM>. It will be understood, in general, that the CPU <NUM> interprets the shift and other signals received by the radio <NUM> and generates an output that controls the motor <NUM>.

The output shaft of motor <NUM> rotates either clockwise or counterclockwise depending on the output from the CPU <NUM>, the result, for example, depending on whether an upshift or a downshift is desired or whether a trim function is desired. The resulting rotation of stage one pinion <NUM> causes rotation of stage one gear <NUM>, which rotates together with stage two pinion <NUM> to rotate stage two gear <NUM>, which rotates together with stage three worm <NUM> to rotate stage three worm wheel <NUM>, which rotates together with stage four pinion <NUM> to rotate sector gear <NUM>. Output gear <NUM> moves output arm <NUM>, which receives the output of gear train or transmission <NUM>. The output arm <NUM> may be considered an element of the transmission <NUM>, but in the illustrated embodiment extends outside of the housing <NUM>.

In the case that a upshift (i.e. a shift to the larger chainring) is desired, castellations of sector gear <NUM> drive motor gearbox module output arm <NUM> clockwise around first link pin <NUM> in <FIG>, which in turn drives upper limit set screw <NUM> along with outer link <NUM> clockwise, causing inner link <NUM> and chain guide <NUM> to move outboard towards the larger chainring. As chain guide <NUM> moves outboard, the magnetic rotary encoder chip on PC board assembly <NUM> in combination with magnet <NUM> is used to monitor the angular position of stage four pinion <NUM> and when the position of stage four pinion <NUM> corresponding to the desired chainring has been reached, power to the motor <NUM> is shut off, since chain guide <NUM> is aligned with the desired chainring. As previously described, second biasing element <NUM> eliminates any play or backlash in the drive gear train or transmission <NUM>, ensuring that chain guide <NUM> is accurately and repeatably positioned. In the case that a downshift (i.e. a shift to a smaller chainring) is desired, castellations of sector gear <NUM> rotate motor gearbox module output arm <NUM> counterclockwise around first link pin <NUM> in <FIG>, which in turn drives saver spring <NUM> along with outer link <NUM> counterclockwise, causing inner link <NUM> and chain guide <NUM> to move inboard towards the smaller chainring. As chain guide <NUM> moves inboard, the magnetic rotary encoder chip on PC board assembly <NUM> along with magnet <NUM> are used to monitor the position of stage four pinion <NUM> and when position of stage four pinion <NUM> corresponding to the desired chainring has been reached, power to the motor <NUM> is shut off, since chain guide <NUM> is aligned with the desired chainring. As previously described, second biasing element <NUM> eliminates any play or backlash in the drive gear train or transmission <NUM>, ensuring that chain guide <NUM> is accurately and repeatably positioned.

After a period of inactivity (e.g., no shift signals received), most of the electronic systems of PC board assembly <NUM> may be configured to shut down to conserve power. During this time, the radio <NUM> is shut down (changed to a low power or unpowered condition) and cannot receive shift signals. A vibration sensor is provided on PC board assembly <NUM> in communication with the CPU <NUM> that causes the electronic systems of PC board assembly, including the radio <NUM>, to turn on again when vibration is detected. The vibrations that naturally occur while riding the bicycle caused by the interaction of the road with the bicycle and by the interaction of the bicycle's various components with each other are sufficiently strong to activate the vibration sensor and prevent the electronic systems of PC board assembly <NUM> from shutting down. But when the bicycle is not being ridden, i.e. parked, the vibration sensor does not detect any vibration and most of the electronic systems of PC board assembly <NUM> are shut down to conserve power after a predetermined amount of time. As soon as the rider makes contact with the bicycle, the resulting vibration activates the vibration sensor, turning the electronic systems on again. The vibration sensor may be a SignalQuest SQ-MIN-<NUM> or a Freescale Semiconductor MMA8451Q.

Claim 1:
An electromechanical front gear changer (<NUM>) for a bicycle (<NUM>) having a chain (<NUM>), comprising:
a base member (<NUM>) attachable to the bicycle (<NUM>);
a linkage (<NUM>) movably coupled to the base member (<NUM>);
a chain guide (<NUM>) movably coupled to the linkage (<NUM>) for contacting the chain (<NUM>);
a motor (<NUM>) supported by the base member (<NUM>);
a gear transmission (<NUM>) driven by the motor (<NUM>) to move the linkage (<NUM>); a CPU (<NUM>) for controlling the motor (<NUM>);
a power supply (<NUM>) supported by the base member (<NUM>) to power the motor (<NUM>) and the CPU (<NUM>);
a receiver (<NUM>) for receiving wireless signals and powered by the power supply (<NUM>), wherein the CPU (<NUM>) is in operative communication with the receiver (<NUM>) and processes the received wireless signals; and
a housing (<NUM>) attached to the base member (<NUM>), wherein the housing (<NUM>) is formed of a material permitting the passage of wireless signals therethrough, and wherein in particular the motor (<NUM>), the gear transmission (<NUM>), receiver (<NUM>), and CPU (<NUM>) are positioned within the housing (<NUM>),
wherein the housing (<NUM>) has a front housing portion (<NUM>) positioned at or near a front of the front gear changer (<NUM>) and a rear housing portion (<NUM>) positioned behind the front housing portion (<NUM>),
wherein the receiver (<NUM>) is positioned in or proximate the front housing portion (<NUM>), and
wherein the power supply (<NUM>) is removably coupled to the rear housing portion (<NUM>).