Patent Description:
The present application generally relates to a front chainring assembly having a removable chainring structure threadably engaged with a chainring carrier, which may include a power meter device. In regard to the prior art reference is made to document <CIT>. This document shows a power meter device comprising: a body comprising a torque input section and a torque output section, the body configured to transmit power between the torque input section and the torque output section, the torque input section adapted to be coupled to a crank arm, wherein the body is rotatable about a rotation axis; a plurality of strain measurement devices coupled to the body, the plurality of strain measurement devices configured to provide a signal indicative of strain detected in the body; and circuitry interpreting the signal and determining a corresponding power transmitted between the torque input section and the torque output section.

A bicycle rider may desire information regarding the amount of power being input into a drive train of a bicycle during use. To accommodate this desire, a power meter device having torque input and output sections may be installed on the bicycle. It also may be desirable to ensure that the power meter device may be used with different chainrings, both to reduce repair and replacement costs as well as providing the rider with different chainring configurations and gear ratio options. At the same time, however, it may be desirable to minimize the weight of the drive train, especially in a competitive cycling environment, without sacrificing the performance of the drive train and/or power meter device.

A power meter device according to the present invention is defined in claim <NUM>. Preferred features are defined in the dependent claims. The following aspects are examples useful for understanding the invention. A device is provided, comprising a body comprising a torque input section and a torque output section. The body is configured to transmit power between the torque input section and the torque output section. The torque input section is adapted to be coupled to a crank arm. The body is rotatable about a rotation axis. The torque output section comprises an outer periphery comprising threads adapted to be coupled to a chainring structure. Moreover, the power meter device comprises a plurality of strain measurement devices which are coupled to the body. The plurality of strain measurement devices are configured to provide a signal indicative of strain detected in the body. The power meter device further comprises a circuitry which interprets the signal and determines a corresponding power that is transmitted between the torque input section and the torque output section.

In some aspects of the invention the the body of the power meter device comprises an annular shoulder extending radially outwardly adjacent the threads, wherein the annular shoulder defines a stop surface adapted to engage the chainring structure.

In some aspects of the invention the p the threads comprise at least three thread starts.

In some aspects of the invention the the threads comprise nine or eighteen thread starts.

In some aspects of the invention the the threads comprise a lead angle of between and including <NUM>° and <NUM>°.

In some aspects of the invention the body comprises an annular cavity disposed radially between the torque input section and the torque output section, the plurality of strain measurement devices attached to a base surface of the annular cavity.

In some aspects of the invention the the plurality of strain measurement devices is spaced apart by openings in the base surface of the annular cavity.

In some aspects of the invention the the torque input section comprises a plurality of torque-transmitting features extending radially inwardly from an inner periphery of the body.

According to the invention, the threads skip at least one thread.

In one aspect, one embodiment of a front chainring assembly includes a chainring carrier adapted to be coupled to a crank arm. The chainring carrier is rotatable about a rotation axis, and includes an outer periphery having carrier threads. A chainring structure includes an inner periphery having chainring threads and an outer periphery comprising a plurality of teeth. The inner periphery of the chainring structure is threadably engaged with the outer periphery of the chainring carrier.

In another aspect, one embodiment of a power meter device includes a body having a torque input section and a torque output section. The body is configured to transmit power between the torque input section and the torque output section, with the torque input section being adapted to be coupled to a crank arm. The body is rotatable about a rotation axis. The torque output section includes an outer periphery having threads adapted to be coupled to a chainring structure. A plurality of strain measurement devices are coupled to the body, with the plurality of strain measurement devices configured to provide a signal indicative of strain detected in the body. Circuitry is provided for interpreting the signal and determining a corresponding power transmitted between the torque input section and the torque output section.

The various embodiments of the front chainring assembly and power meter device, and the methods for the use and assembly thereof provide significant advantages over other chainring assemblies, power meter devices, and methods. For example and without limitation, a chainring structure can be quickly and easily replaced simply by rotating the chainring structure relative to the chainring carrier. The threaded engagement eliminates the need for lugs and bolts interfacing between the chainring carrier and the chainring structure, and the attendant time and costs associated with disassembling the assembly. As such, the overall weight of the assembly may be reduced while maintaining the ability to easily replace or interchange chainrings. Moreover, the chainring carrier may be incorporated into a power meter device, which provides for reliable performance of the power meter.

The foregoing paragraphs have been provided by way of general introduction and are not intended to limit the scope of the claims presented below. The various preferred embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

In some aspects a front chainring assembly comprising a chainring carrier adapted to be coupled to a crank arm, wherein the chainring carrier is rotatable about a rotation axis, and wherein the chainring carrier comprises an outer periphery comprising carrier threads; and a chainring structure comprising an inner periphery comprising chainring threads and an outer periphery comprising a plurality of teeth, wherein the inner periphery of the chainring structure is threadably engaged with the outer periphery of the chainring carrier.

In some aspects the front chainring assembly of aspect <NUM>, wherein the chainring carrier comprises an annular shoulder extending radially outwardly adjacent the carrier threads on the outer periphery of the carrier, wherein the annular shoulder defines a stop surface, wherein the chainring structure is rotatable relative to the chainring carrier between a disengaged position and an engaged position, wherein the chainring structure engages the stop surface when in the engaged position.

In some aspects the front chainring assembly of aspect <NUM> or <NUM>, wherein at least the carrier threads comprise at least three thread starts.

In some aspects the front chainring assembly of one of the preceding aspects, wherein at least the carrier threads comprise nine or eighteen thread starts.

In some aspects the front chainring assembly of one of the preceding aspects, wherein the carrier threads and the chainring threads comprise a lead angle of between and including <NUM>° and <NUM>°.

In some aspects the front chainring assembly of one of the preceding aspects, wherein the chainring carrier comprising an annular cavity disposed radially between the inner and outer peripheries of the chainring carrier, the chainring carrier comprising a power meter device disposed within the annular cavity, the power meter device configured to determine the power transmitted between the inner periphery of the chainring carrier and the outer periphery of the chainring carrier.

In some aspects the front chainring assembly of aspect <NUM>, wherein the power meter comprises a plurality of strain measurement devices attached to a base surface of the annular cavity, the strain measurement devices spaced apart by openings in the base surface of the annular cavity.

In some aspects the front chainring assembly of one of the preceding aspects, further comprising a crank arm.

In some aspects the front chainring assembly of aspect <NUM>, further comprising a first pairing feature formed on one of the crank arm and the chainring carrier and a second pairing feature formed on the other of the crank arm and the chainring carrier to position the chainring carrier on the crank arm, and to provide a torque-transmitting coupling between the crank arm and the chainring carrier.

In some aspects the front chainring assembly of one of the preceding aspects, wherein the chainring structure comprises a first portion comprising the plurality of teeth and a second portion comprising the chainring threads, wherein the first portion is releasably coupled to the second portion.

In some aspects the front chainring assembly of aspect <NUM>, wherein the first portion is releasably coupled to the second portion with a plurality of fasteners.

In some aspects the front chainring assembly of one of the preceding aspects, wherein the chainring structure includes a single chainring and the plurality of teeth comprises a first group of teeth and a second group of teeth, the first group of teeth having an axial width greater than an axial width of the second group of teeth.

In some aspects the front chainring assembly of one of aspects <NUM> to <NUM>, wherein the chainring structure comprises a first chainring axially spaced from a second chainring, the plurality of teeth comprising a first plurality teeth on an outer periphery the first chainring and a second plurality of teeth on an outer periphery of the second chainring, wherein the first plurality of teeth is greater than the second plurality of teeth.

In some aspects the front chainring assembly of one of the preceding aspects, wherein the chainring threads comprise at least one removed thread, and wherein the carrier threads comprise at least one skipped thread.

In some aspects the front chainring assembly of one of the preceding aspects, further comprising a locking member releasably coupled to the chainring carrier, wherein the locking member comprises an insert portion removeably received in an elongated recess formed adjacent the inner periphery of the chainring structure, wherein the insert portion is engageable with the chainring structure so as to prevent the chainring structure from being threadably disengaged from the outer periphery of the chainring carrier.

Objects, features, and advantages of the present invention will become apparent upon reading the following description in conjunction with the drawing figures, in which:.

It should be understood that the term "plurality," as used herein, means two or more. The term "longitudinal," as used herein means of or relating to a length or lengthwise direction. The term "lateral," as used herein, means situated on, directed toward or running in a side-to-side direction. The term "coupled" means connected to or engaged with, whether directly or indirectly, for example with an intervening member, and does not require the engagement to be fixed or permanent, although it may be fixed or permanent. The terms "first," "second," and so on, as used herein are not meant to be assigned to a particular component so designated, but rather are simply referring to such components in the numerical order as addressed, meaning that a component designated as "first" may later be a "second" such component, depending on the order in which it is referred. It should also be understood that designation of "first" and "second" does not necessarily mean that the two components or values so designated are different, meaning for example a first direction may be the same as a second direction, with each simply being applicable to different components. The terms "upper," "lower," "rear," "front," "fore," "aft," "vertical," "horizontal," "right," "left," "inboard," "outboard" and variations or derivatives thereof, refer to the orientations of an exemplary bicycle <NUM>, shown in <FIG>, from the perspective of a user seated thereon, for example with an "inboard" component or feature being closer to a vertical mid-plane of the bicycle extending in a direction A. The term "transverse" means non-parallel. The terms "outer" and "outwardly" refers to a direction or feature facing away from a centralized location, for example the phrases "radially outwardly," "radial direction" and/or derivatives thereof, refer to a feature diverging away from a centralized location, for example a rotation axis <NUM> of the chainring assembly as shown in <FIG>. Conversely, the terms "inward" and "inwardly" refers to a direction facing toward the centralized or interior location. The term "subassembly" refers to an assembly of a plurality of components, with subassemblies capable of being further assembled into other subassemblies and/or a final assembly, such as the bicycle <NUM>.

<FIG> illustrates one example of a human powered vehicle. In this example, the vehicle is one possible type of bicycle <NUM>, such as a mountain bicycle. The bicycle <NUM> has a frame <NUM>, handlebars <NUM> near a front end of the frame, and a seat or saddle <NUM> for supporting a rider over a top of the frame. The bicycle <NUM> also has a first or front wheel <NUM> carried by a front fork subassembly <NUM> supporting the front end of the frame. The bicycle <NUM> also has a second or rear wheel <NUM> supporting a rear end of the frame <NUM>. The rear end of the frame <NUM> may be supported by a rear suspension component <NUM>, such as a rear shock. The bicycle <NUM> also has a drive train <NUM> with a crank assembly <NUM> that is operatively coupled via a roller chain <NUM> to a rear cassette <NUM> or a driven sprocket assembly near the hub providing a rotation axis of the rear wheel <NUM>. The roller chain <NUM> includes a plurality of inner links and plurality of outer links that interconnected in an alternating manner by a plurality of pins <NUM>. Each of the inner links includes a pair of parallel inner link plates <NUM>. Each of the outer links includes a pair of parallel outer link plates <NUM>. Each of the pins <NUM> has a roller that is rotatably disposed thereon. The crank assembly <NUM> includes at least one, and typically two, crank arms <NUM> and pedals <NUM>, along with a front chainring assembly <NUM> or a drive sprocket assembly. A crank spindle or shaft (not shown) may connect the two crank arms. The crank shaft defines a center rotational axis <NUM> of the chainring assembly <NUM>. The crank assembly may also include other components.

A rear gear change device <NUM>, such as a derailleur, is disposed at the rear wheel <NUM> to move the roller chain <NUM> through different sprockets of the cassette <NUM>. In one embodiment, a front gear changer device, such as a derailleur, may be provided to move the chain <NUM> through multiple sprockets of the chainring assembly. In the illustrated example, the saddle <NUM> is supported on a seat post <NUM> having an end portion received in a top of a frame seat tube <NUM> of the frame. A clamping ring <NUM> may be tightened to secure the upper seat tube <NUM> to the lower frame seat tube <NUM>.

In <FIG>, the arrow A depicts a normal riding or forward moving direction of the bicycle <NUM>. While the bicycle <NUM> depicted in <FIG> is a mountain bicycle, the chainring assembly <NUM>, including the specific embodiments and examples disclosed herein as well as alternative embodiments and examples, may be implemented on other types of bicycles. For example and without limitation, the disclosed chainring assembly <NUM> may be used on road bicycles, as well as bicycles with mechanical (e.g., cable, hydraulic, pneumatic, etc.) and non-mechanical (e.g., wired, wireless) drive systems.

Now referring to <FIG> and <FIG>, the front chainring assembly <NUM> includes a chainring carrier <NUM>, <NUM> that is adapted to be coupled to one of the crank arms <NUM>. The chainring carrier is rotatable about the rotation axis <NUM>. The chainring carrier includes an outer periphery <NUM>, or outer diameter/circumference, configured with carrier threads <NUM>, <NUM>. The chainring carrier <NUM>, <NUM> includes an annular shoulder <NUM>, configured as a radially extending flange, that extends radially outwardly adjacent the carrier threads <NUM>, <NUM> on the outer periphery of the carrier. The annular shoulder defines a stop surface <NUM>, formed along an inboard face of the shoulder <NUM> in one embodiment. The stop surface <NUM> is substantially planar and is arranged vertically when the bicycle is in an upright riding position as shown in <FIG>. The shoulder <NUM> has a greater outer diameter than the carrier threads <NUM>, <NUM>, such that the stop surface <NUM> is exposed to an outboard side surface, or face <NUM>, of a chainring structure <NUM>, <NUM>, <NUM>, <NUM> threadably engaged with the carrier threads <NUM>, <NUM>. The annular shoulder <NUM> may be positioned outboard of the carrier threads <NUM> as shown in <FIG> in an axial direction, defined for example by the axis <NUM>, or located inboard of the carrier threads in the axial direction in other embodiments.

The chainring carrier <NUM>, <NUM> includes, or has formed thereon, one of a first or second pairing feature <NUM>, <NUM>, while the crank arm <NUM> includes, or has formed thereon, the other of the first or second pairing feature <NUM>, <NUM>. The first and second pairing features <NUM>, <NUM> position the chainring carrier <NUM> relative to the crank arm <NUM> and provide a torque-transmitting coupling between the crank arm <NUM> and the chainring carrier <NUM>. In another embodiment, the crank arms and the carrier may be torque transmittingly coupled in other ways, such as by being directly attached to the crank spindle and/or each other.

In one embodiment, and referring to <FIG> and <FIG>, the chainring structure <NUM>, <NUM> is a single or solitary chainring or drive sprocket configured as an annular sprocket with an inner periphery <NUM>, or inner circumference/diameter, configured with chainring threads <NUM>, <NUM> and an outer periphery configured with a plurality of circumferentially spaced teeth <NUM>, which engage the roller chain <NUM>. The number of teeth may range between twenty-eight and forty-eight teeth. The inner periphery <NUM> of the chainring, and in particular the chainring threads <NUM>, <NUM>, is/are threadably engaged with the outer periphery <NUM> of the chainring carrier, and in particular the carrier threads <NUM>, <NUM>. The chainring <NUM>, <NUM> is rotatable relative to the chainring carrier <NUM>, <NUM> between a disengaged position and an engaged position, wherein the chainring <NUM>, <NUM>, and in particular the outboard surface or face <NUM> thereof, engages the stop surface <NUM> when the chainring <NUM>, <NUM> is in the engaged position. The chainring <NUM>, <NUM> may be configured with a single, double or triple ring(s), with at least one of the ring(s) having or defining the inner threaded periphery <NUM>. In one embodiment, the plurality of teeth <NUM> of the chainring <NUM> includes a first group of teeth <NUM> and a second group of teeth <NUM>, wherein the first group of teeth <NUM> have an axial width W1 greater than an axial width W2 of the second group of teeth <NUM>. Each of the first group of teeth <NUM> has an axial width W1 such that the teeth <NUM> fit within a space between outer link plates <NUM> of the roller chain <NUM> but do not fit within a space between the inner link plates <NUM> of the roller chain <NUM>. The first group of teeth <NUM> may include axial protrusions <NUM>, <NUM> configured to fill the space between the outer link plates <NUM> and/or interact with the outer link plates <NUM> of the roller chain <NUM>. There may be an inboard protrusion <NUM> and/or an outboard protrusion <NUM> on the first group of teeth <NUM>. Each of the second group of teeth <NUM> has an axial width W2 such that the teeth <NUM> fit within a space between the inner link plates <NUM> of the chain <NUM>. The inboard/outboard sides or faces <NUM>, <NUM> of the chainring <NUM> may be dished inward or outward to account for the chain line.

Referring to <FIG> and <FIG>, in another embodiment, the chainring structure <NUM> includes a first portion <NUM> configured with the plurality of teeth and a second portion <NUM> including the chainring threads <NUM> and defining a surface or face <NUM> that abuts and engages the stop surface <NUM> of the carrier <NUM>. The first and second portions may be configured as first and second annular rings, with the first portion being releasably coupled to the second portion, for example with a plurality of fasteners <NUM> or screws. The second portion <NUM>, otherwise referred to as an adapter, provides an interface between the chainring carrier <NUM> and the first portion, which may be configured as a conventional chainring with a pattern of holes <NUM> (shown as four) aligned with lugs <NUM> (shown as four) extending radially outwardly from the adapter. Each lug <NUM> includes a threaded opening <NUM>, or alternatively a through opening. The fasteners <NUM> are inserted through the holes <NUM> and threadably engage the holes <NUM> defined in the lugs <NUM> in one embodiment. Alternatively, a bolt may be inserted through the holes <NUM> and the through opening in the lug and be secured with a nut. It should be understood that the plurality of fasteners <NUM> and corresponding holes <NUM> and openings <NUM> may be more or less than four.

In another embodiment shown in <FIG>, the chainring structure <NUM> is configured with a pair of (e.g., first and second) axially spaced annular drive sprockets <NUM>, <NUM>, or chainrings. A first or outboard sprocket is <NUM> is configured as an annular drive sprocket with an outer periphery defined by a first outer diameter D1 and configured with a first plurality of circumferentially spaced teeth <NUM>, which engage the roller chain <NUM> when the roller chain <NUM> is shifted onto the outboard sprocket <NUM>, for example by the front gear changer device, such as a derailleur. A second or inboard sprocket <NUM> is configured as an annular drive sprocket with an outer periphery defined by a second outer diameter D2 and configured with a second plurality of circumferentially spaced teeth <NUM>, which engage the roller chain <NUM> when the chain <NUM> is shifted onto the inboard sprocket <NUM>, for example by the front gear changer device, such as a derailleur. The inboard sprocket <NUM> is coupled to the outboard sprocket <NUM> with at least a circumferential or annular wall <NUM>. The annular wall <NUM> may be formed of the same single piece material as the outboard sprocket <NUM> and inboard sprocket <NUM>. In one embodiment, the outer diameter D1 is greater than outer diameter D2. The number of teeth of the outboard sprocket <NUM> may range between forty-six and fifty teeth and the number of teeth of the inboard sprocket <NUM> may range between thirty-three and thirty-seven teeth. The front gear changer device is operable to move the chain between the inboard and outboard sprockets <NUM>, <NUM>. The chainring structure <NUM> has an inner periphery <NUM> or inner circumference/diameter, configured with chainring threads <NUM>. The chainring threads <NUM>, is/are threadably engaged with the outer periphery <NUM> of the chainring carrier, and in particular the carrier threads <NUM>. The chainring structure <NUM> is rotatable relative to the chainring carrier <NUM> between a disengaged position and an engaged position, wherein the chainring structure <NUM>, and in particular the outboard surface or face <NUM> thereof, engages the stop surface <NUM> when the chainring structure <NUM> is in the engaged position. The outboard and outboard sprockets <NUM>, <NUM> may have various recesses or openings to lighten the chainring <NUM>.

Both the chainring threads <NUM>, <NUM> and the carrier threads <NUM>, <NUM> may be configured with a plurality of thread starts <NUM>, <NUM> in various embodiments. For example, the chainring threads and the carrier threads may each include at least three thread starts. In one embodiment, the chainring threads <NUM>, <NUM> and the carrier threads <NUM>, <NUM> include at least nine thread starts, which allows for a greater angle of approach. In other embodiments, the chain ring threads and the carrier threads may each include eighteen (<NUM>) thread starts, or as many as thirty-six (<NUM>) thread starts. In one embodiment, nine thread starts results in about <NUM>/<NUM> of a rotation for installation of the chainring structure <NUM>, <NUM>, <NUM> on the carrier <NUM>, or rotation between a disengaged position and an engaged position. In this way, the multiple starts provide for minimal rotation during installation, but allows for sufficient rotation preventing inadvertent loosening of the chainring structure from the carrier, for example if the chainring is accidentally struck by an obstacle such as a rock while a user is riding the bicycle.

The angle of approach may be described as the lead angle (α). Less than three starts may create an unnecessarily flat approach between the face <NUM>, <NUM>, <NUM> of the chainring structure and the stop surface <NUM> of the shoulder, such that the torque or force required to loosen or remove the chainring structure becomes excessive. In various embodiments, the lead angle (α) is between and including <NUM>° and <NUM>°, and preferably at an angle suitable such that the chainring structure <NUM>, <NUM>, <NUM>, <NUM> does not become self-releasing from the carrier <NUM> once the chainring structure <NUM>, <NUM>, <NUM>, <NUM> is installed on the carrier <NUM>, <NUM> and torqued to a pre-determined amount. As shown in Table <NUM>, various thread configuration embodiments may include for example from <NUM> to <NUM> thread starts, with corresponding lead angles of <NUM> degrees and <NUM> degrees and installation rotations of <NUM> degrees and <NUM> degrees respectively. Other exemplary embodiments may be configured with <NUM> and <NUM> thread starts with corresponding lead angles of <NUM> degrees and <NUM> degrees and installation rotations of <NUM> degrees and <NUM> degrees respectively. The pitch and lead of the various exemplary embodiments is also provided in Table <NUM>. It should be understood that in some embodiments, the chainring threads <NUM>, <NUM> and the carrier threads <NUM>, <NUM> may be single start and may be either formed as right or left hand threads so long as the chainring structure <NUM>, <NUM>, <NUM>, <NUM> tightens against the shoulder stop surface <NUM>, or alternatively a locking member <NUM>, configured as a pin in one embodiment, with pedaling. The lateral, inboard/outboard positioning of the chainring structure <NUM>, <NUM>, <NUM>, <NUM> can be defined by the location of the shoulder <NUM> and stop surface <NUM> along the axial direction, or alternatively the locking member <NUM> or pin that can be used to lock the chainring structure into position or some combination of both. If needed, rotational alignment can be accomplished via thread clocking or pin location clocking between the chainring structure and carrier.

As mentioned, the pattern of the threads <NUM>, <NUM>, <NUM>, <NUM> on the chainring structure and carrier are oriented such that chainring tightens on the carrier during riding. Accordingly, in the embodiment of <FIG>, wherein the carrier threads <NUM> are positioned inboard of the shoulder <NUM> and stop surface <NUM>, and the chainring structure <NUM>, <NUM>, <NUM> is threaded onto the carrier <NUM> from the inboard side of the carrier, the threads <NUM>, <NUM> are right-hand threads, or tighten by a clockwise rotation, meaning the chainring structure <NUM>, <NUM>, <NUM> rotates clockwise relative to the carrier <NUM> when viewed from the inboard side and the carrier <NUM> rotates clockwise relative to the chainring structure <NUM>, <NUM>, <NUM> when viewed from the outboard side. If the carrier threads <NUM> are positioned outboard of the shoulder <NUM> and stop surface <NUM>, the threads <NUM>, <NUM> are preferably configured as left-hand threads, or tighten by counterclockwise rotation. In one embodiment, the chainring threads <NUM> and the carrier threads <NUM> are configured as <NUM>°V threads, although it should be understood that other types of threads may be suitable.

Referring to <FIG>, one or more chainring threads <NUM> may be removed from the chainring structure <NUM> and one or more carrier threads <NUM> may skipped on the carrier <NUM>. For example, as shown in <FIG>, a pair of chainring threads <NUM>, or thread starts, may be removed from the chainring structure. Referring to <FIG>, a pair of carrier threads <NUM>, or thread starts, may be skipped on the carrier. The removed chainring thread(s) <NUM>, and the skipped carrier thread(s) <NUM>, create smooth surfaces along the inner and outer peripheries <NUM>, <NUM> of the respective chainring structure <NUM> and carrier <NUM> respectively. The removal and skipping of the chainring and carrier thread(s) may ensure that the chainring can only be clocked in one orientation. Because the thicker "skipped" thread <NUM> may only fit into the larger "removed" thread <NUM> or thread start, the interface rotationally orients the chainring structure <NUM> to the carrier <NUM>. By providing two of these features (skipped and removed threads <NUM>, <NUM>) on each of the chainring structure and carrier, for example at <NUM> degree spacing, proper assembly of the chainring structure <NUM> onto the carrier <NUM> may be facilitated. In this way, the thread count, and thread start count, of each of the chainring threads and carrier threads includes both the number of actual threads <NUM>, <NUM> and thread starts <NUM>, <NUM> and also the number of removed and skipped threads <NUM>, <NUM> respectively. For example, a chainring structure that has nine (<NUM>) threads and thread starts, with two of the threads <NUM> removed such that only seven (<NUM>) threads <NUM> and thread starts <NUM> are actually present, is still considered to have nine (<NUM>) threads and thread starts. It should be understood that the removed and skipped threads may be spaced at other angular intervals, and that more than two removed and skipped threads may be provided. In another embodiment, only a single removed and skipped thread may be provided on each of the chainring structure and carrier respectively.

During assembly, the chainring structure <NUM>, <NUM>, <NUM>, <NUM> is threaded onto the carrier <NUM>, <NUM> until the stop surface <NUM> engages or abuts the face <NUM>, <NUM>, <NUM>, or outboard side surface, of the chainring structure. Further rotation of the carrier <NUM>, <NUM> relative to the chainring structure <NUM>, <NUM>, <NUM>, <NUM> will frictionally secure or couple the chainring structure <NUM>, <NUM>, <NUM>, <NUM> and carrier <NUM>, <NUM> through the abutting surfaces <NUM>, <NUM>, <NUM>, <NUM> and through the engagement between the carrier threads <NUM>, <NUM> and the chainring threads <NUM>, <NUM>. During use, opposing forces applied by the crank arm <NUM> to the carrier <NUM>, <NUM> and by the roller chain <NUM> to the chainring structure <NUM>, <NUM>, <NUM>, <NUM>, will maintain the coupling of the carrier <NUM>, <NUM> and the chainring structure <NUM>, <NUM>, <NUM>, <NUM> through the abutting surfaces <NUM>, <NUM>, <NUM>, <NUM>, and through the engagement between the carrier threads <NUM>, <NUM> and the chainring threads <NUM>, <NUM>, and thereby transfer torque between the crank arm and chain, and between the carrier and chainring structure.

Referring to <FIG>, the locking member <NUM> may be configured with a flange <NUM> that is nested in an cutout <NUM> formed along, or adjacent, an outer periphery of the carrier. The flange <NUM> may be releasably coupled to the carrier <NUM> with a fastener <NUM>, such as screw, with an outer surface <NUM> of the flange lying flush with, or recessed relative to, the side surface of the carrier <NUM>. The locking member also includes an insert portion <NUM> that extends inboard from the flange <NUM> and lies against a recess <NUM> formed in the outer periphery of the carrier. In one embodiment, the insert portion <NUM> may be configured as a pin. The chainring structure <NUM> may include an elongated, circumferential recess <NUM> formed adjacent the inner periphery of the chainring structure, with a slot <NUM> defined between the chainring structure and the carrier. After the chainring structure <NUM> has been threaded onto the carrier <NUM>, the locking member <NUM> may be releasably coupled to the carrier <NUM> with the insert portion <NUM> disposed in the recess <NUM>, or slot <NUM>. The chainring structure <NUM> may rotate slightly relative to the carrier <NUM> thereafter, but the insert portion <NUM> may then become engaged with the chainring structure, for example with one or the other of the end surfaces <NUM>, <NUM> of the recess, so as to prevent the chainring structure <NUM> from being threadably disengaged from the outer periphery of the chainring carrier <NUM>. The relative dimensions of the width WIP of the insert portion <NUM> and the length LR of the recess <NUM> and slot <NUM>, i.e., WIP ≤ LR, allows for some variation in the alignment of the insert portion in the slot due to manufacturing tolerances, and also permits the chainring strucure to unthread a small amount before the end surfaces <NUM>, <NUM> of the recess contact or engage the insert portion <NUM>, or pin. This movement and engagement may indicate to the user that the chainring structure <NUM> has been loosened if the locking member has not been removed.

Referring to <FIG>, <FIG>, the chainring carrier <NUM> includes an annular cavity <NUM> disposed radially between the inner and outer peripheries <NUM>, <NUM> of the chainring carrier <NUM> on the outboard side of the carrier. A power meter device <NUM> is disposed within the annular cavity <NUM> and coupled to the carrier <NUM>. The power meter device <NUM> is configured to determine the power transmitted between the inner periphery <NUM> and the outer periphery <NUM> of the chainring carrier <NUM>. Various embodiments and components of a suitable power meter device are disclosed in U. Patent Publication <NUM>/<NUM>. In one embodiment, the power meter <NUM> includes a plurality of strain measurement devices <NUM> attached to a base surface <NUM> of the annular cavity <NUM>. The strain measurement devices <NUM> are spaced apart by openings <NUM> in the base surface <NUM> of the annular cavity <NUM>. It should be understood, however, that the chainring carrier <NUM> may be used on a bicycle without any power meter device coupled thereto, with the carrier <NUM> threadable interfacing with the chainring structure <NUM>, <NUM>, <NUM> as disclosed herein.

The strain measurement devices may be physically integrated with the operational circuitry of a bicycle power meter. Physically integrating strain measurement devices and operational circuitry structure may cause the construction and/or precise positioning of power meter components to be accomplished in a less expensive and/or less resource intensive manner. The strain measurement devices may be attached directly to a physical structure containing the power meter operational circuitry, such as a printed circuit board ("PCB") substrate, thus coupling the strain measurement devices and the power meter circuitry into a singular power meter PCB assembly. Further, fixably attaching the strain measurement devices to the PCB such that the position of the strain measurement devices in a plane of the PCB substrate is fixed relative to other components of the PCB assembly may allow for easier alignment and/or positioning of the strain measurement devices. For example, the alignment of the strain measurement devices may be established based on alignment of features of the PCB, which may be features of the PCB substrate and/or other PCB components.

The power meter device <NUM> may be integrated with a body, such as the chainring carrier <NUM>, and may include the one or more strain measurement devices <NUM>, such as strain gauges, arranged in a generally annular or circumferential pattern about the body. The strain measurement devices <NUM> are connected to circuitry and/or other sensors to generate power information, which may be transmitted to another bicycle component or external device for further processing and/or display. Alternatively, the power meter may be coupled with the chainring assembly directly, for example without the use of a chainring carrier.

The power meter <NUM> may include an annular printed circuit board ("PCB") with strain measurement devices attached directly to the PCB. For example, the strain measurement device may be electrical resistance type strain gauges that are generally planar and/or laminar in construction with a layer of conductive metal formed in one or more patterns on a non-electrical substrate, film, paper, or other material. The conductive metal pattern or patterns may be formed of various metallic constructions, including foil and/or wire. The conductive metal pattern or patterns may be formed of any metal or metal alloy. For example, copper or cooper alloys such as constantan may be used. Planar strain measurement devices also may include electrical contact connection surfaces configured for connection to circuitry of the PCB.

The PCB has a substrate to which components of the PCB are applied and/or attached. The substrate may form the structure and/or shape of the PCB. The substrate may be any substance operable to form the underlying attachment of the PCB components. For example, silicon, silicon dioxide, aluminum oxide, sapphire, germanium, gallium arsenide ("GaAs"), an alloy of silicon and germanium, or indium phosphide ("InP"), may be used. The substrate may be rigid or flexible. In an embodiment, the substrate forms an annular rigid ring. The rigid ring may be one continuous piece of substrate material. In an embodiment, a substrate ring has an inner diameter and an outer diameter defining the extents of the substrate there between.

The connection to the circuitry of the PCB may be accomplished using any technique. In an embodiment, the connection is accomplished through an application of layer of a conductive medium, such as solder, between the electrical contact connection surfaces of the planar strain measurement device and contact connection surfaces of the PCB which provide electrically communicative contact with other electronic components connected to the PCB, such as a processor, memory, other sensors, and/or other electric or electronic devices. Such connection may be made directly, without the use of an intermediate conductive connector, such as an elongated electrical lead, wire, or other device. For example, the conductive medium may be bounded on opposing sides by the electrical contact connection surfaces of the PCB and strain measurement device. In this example, the electrical contact connection surfaces of the PCB and strain measurement device may be secured substantially parallel and opposing each other by the conductive medium. Further, as is described above, the connection may provide that the strain measurement device is fixably attached to the PCB substrate such that the strain measurement device is secure and not movable in a radial plane of the PCB substrate relative to other features and/or components of the PCB. As described herein, the PCB may be attached to a body of a drivetrain to form a power meter.

<FIG> and <FIG> show a body, here embodied as the chainring carrier <NUM>, having an integrated power meter <NUM>. The chainring carrier <NUM> may be made of any material operable to transmit torque, and a resulting power, between a torque input section <NUM> and a torque output section <NUM>. For example, aluminum alloys may be used. The crank arm <NUM> is shown attached to the chainring carrier <NUM>. The crank arm <NUM> has a pedal attachment section <NUM> to which the pedal <NUM> may be attached such that a bicycle rider may input pedaling forces into the bicycle drive train. These pedaling forces result in a torque that causes the crank arm <NUM> and attached chainring carrier <NUM> to rotate about the crank or rotation axis <NUM>. The crank arm <NUM> has a spindle attachment feature <NUM> that provides for attachment to a spindle that connects the crank arm and pedal assembly disposed on an opposing side of the bicycle to facilitate pedaling with both feet of the bicycle rider. The spindle attachment feature may be any feature operable to transfer torque, such as a splined interface. As such, torque from either crank arm <NUM> may be transferred into the chainring carrier <NUM> through the crank arm <NUM> attachment to the chainring carrier. The crank arm <NUM> may be attached to the chainring carrier <NUM> using any technique operable to transmit torque between the crank arm <NUM> and a torque input section <NUM> of the chainring carrier <NUM>. The torque input section <NUM> includes a plurality of torque-transmitting features, such as the pairing features <NUM>, extending radially inwardly from an inner periphery <NUM> of the body.

In an embodiment, the crank arm <NUM> is connected as is described in U. Patent Application Publication <NUM>/<NUM> and/or U. Patent Publication <NUM>/<NUM>.

For example, as shown in <FIG>, a crank arm <NUM> and chainring carrier <NUM> may be attached with corresponding features and with a distinct torque transmitting connection, such as with a bolted connection. In this example, the chainring carrier <NUM> is sized and shaped to connect to the crank arm <NUM>. A first pairing feature <NUM> is formed on one of the crank arm <NUM> and the chainring carrier <NUM> and a second pairing feature <NUM> is formed on the other of the crank arm <NUM> and the chainring carrier <NUM> to position the chainring carrier on the crank arm. A clearance is defined between the first and second pairing features <NUM>, <NUM> when the first and second pairing features <NUM>, <NUM> are paired. A torque-transmitting coupling <NUM>, such as through bolted connection including bolts <NUM>, is formed on the crank arm <NUM> and the chainring carrier <NUM> and is configured to transmit substantially all of the torque applied to the chainring carrier <NUM> from the crank arm <NUM>.

A power meter cover <NUM> is provided to protect other power meter components installed within and/or on the body, such as a PCB assembly described below with respect to <FIG>, <FIG>, and <FIG>. The power meter cover <NUM> may be constructed of any material operable to provide for the protection of the internal power meter <NUM> components. For example, aluminum alloys may be used. In an embodiment, the power meter <NUM> may communicate signals wirelessly and the power meter cover <NUM> may be made of a material that is radio frequency ("RF") transparent, such as polycarbonate or other materials. The power meter cover <NUM> may be attached to the body, in this embodiment the chainring carrier <NUM>, using any technique. For example adhesives may be used to attach the power meter cover <NUM>. A power supply casing <NUM> is also provided to both secure and protect a power supply for the power meter <NUM>. In an embodiment, the power supply casing <NUM> includes a removable power supply cover <NUM> to provide access to the power supply. A torque output section <NUM> is shown on the chainring carrier <NUM>. Provided in the torque output section <NUM> in the displayed embodiment are torque output member attachment features <NUM>, including the peripheral threads <NUM> and the interface between the shoulder stop surface <NUM> and the face of the chainring, which transmits the torque from the carrier to the chainring.

The chainring carrier <NUM> includes a strain measurement section <NUM>, which may include one or more strain measurement features <NUM>. The strain measurement features <NUM> are formed into the chainring carrier <NUM> to provide for positioning of strain measurement devices to detect and/or quantify mechanical deformations of the chainring carrier <NUM> due to torque applied between the torque input section <NUM> and the torque output section <NUM>. For example, the strain measurement devices <NUM>, and features <NUM>, may be spaced apart by openings <NUM> formed in the base surface <NUM> of the annular cavity <NUM>. The strain measurement devices <NUM> may be electrical resistance type strain gauges attached to the strain measurement features <NUM>.

As shown in <FIG>, <FIG>, the chainring carrier <NUM> includes the cavity <NUM> configured for installation of the PCB assembly <NUM> and/or other power meter <NUM> components. The cavity <NUM> may include an alignment feature <NUM> which corresponds to substrate alignment feature <NUM> formed in a substrate <NUM> of the PCB assembly <NUM>. The power supply components are hidden from view, though the correlation of these alignment features <NUM>, <NUM> the PCB assembly <NUM> may be appropriately aligned with the chainring carrier <NUM>. Other alignment features may also be used and/or formed into the PCB substrate <NUM>.

The PCB assembly <NUM> also includes a plurality of strain measurement devices <NUM> attached to the substrate <NUM> and/or other parts of the PCB assembly <NUM>. The strain measurement devices <NUM> are configured to provide a signal indicative of strain in an attached body. The signal may be interpreted and acted upon by circuitry <NUM> of the power meter, schematically shown in <FIG>. The circuitry <NUM> may be configured to interpret the signal indicative of strain, and calculate a corresponding mechanical power being transmitted through the attached body.

In the displayed embodiment the strain measurement devices <NUM> are attached at strain measurement device attachment features <NUM> formed in the substrate <NUM>.

In the displayed embodiment, the strain measurement device attachment features <NUM> form a vacancy or void. The void may provide access to the strain measurement devices <NUM> in an axial direction of the PCB assembly <NUM>, such as along a direction of the axis of rotation <NUM>. This access may be used during installation of the PCB assembly <NUM> into a body such as the chainring carrier <NUM>. For example, to generate a quality attachment of the strain measurement devices <NUM> a clamp may be used for attachment to the body during a curing process. As shown, the strain measurement device attachment features <NUM> are configured to allow the attachment of the strain measurement devices <NUM> so that the strain measurement devices do not protrude beyond an inner diameter <NUM> of the substrate <NUM>. This configuration may provide for a maximized substrate <NUM> surface area available for circuitry implementation, but a minimized total surface area of the PCB assembly, particularly in an annular substrate implementation wherein such a configuration may optimize and/or minimize the radial extents of the PCB assembly installation. Further, the plurality of strain measurement device attachment features <NUM> may be disposed so as to be circumferentially spaced around the axis <NUM>.

As shown, the strain measurement devices <NUM> are attached at a radially inner edge of the substrate <NUM>. Alternatively, the strain measurement devices <NUM> may be attached at a radially out edge of the substrate <NUM>, or between the radially inner and radially outer edge of the substrate <NUM>.

The power supply for the power meter <NUM> is attached both physically and electrically using a contact structure and a metallic screw. As shown, the alignment feature <NUM> also provides for the attachment of the power supply for the power meter <NUM> using the metallic screw. Alignment features may be provided without facilitation for power supply attachment as well.

The PCB assembly <NUM> includes circuitry <NUM>. The circuitry <NUM> may involve one or more processors <NUM>, as well as other electric and/or electronic components as well as additional sensors <NUM>, such as an accelerometer. The circuitry may also include one or more antennae <NUM> as part of the communication interface <NUM>. Additional or alternative alignment features <NUM>, <NUM> used for aligning the PCB assembly <NUM> to a body of a bicycle drivetrain may be formed into the substrate <NUM> of the PCB. For example, one or more notches <NUM> may be cut into an interior and/or exterior edge of the substrate <NUM>. The notches <NUM> may be configured to correspond to corollary features of the body to which the PCB assembly <NUM> is to be attached. Also, one or more holes <NUM> may be formed in the substrate <NUM> which may be used by an assembly tool or handler to specifically attach to the PCB assembly <NUM> in a particular orientation. The tool and/or handler may then be aligned to the body to which the PCB assembly is to be attached such that the PCB assembly <NUM> is aligned properly to the body. For example, the alignment features <NUM>, <NUM>, <NUM> may be used independently or in combination to align the one or more strain measurement devices <NUM> to the body.

The substrate <NUM> operates to connect, and/or provide structure for the circuitry and attached components of the PCB assembly <NUM>. The substrate <NUM> may be flexible or rigid. In an embodiment, the substrate <NUM> is a rigid substrate providing a durable basis for the PCB assembly <NUM>. The substrate <NUM> is formed to provide shape and other substance for the PCB assembly <NUM>. For example, as shown, the substrate <NUM> is formed in an annular construction and/or shape. Such an annular shape facilitates installation of the PCB assembly <NUM> around a torque input section of a body.

At least one strain measurement device <NUM> may be attached to the PCB assembly <NUM> such that the at least one strain measurement device <NUM> is fixed in a plane P of the PCB assembly <NUM> relative to at least one feature of the PCB assembly <NUM>. For example, the strain measurement devices <NUM> may be fixed relative to one or more of the alignment features <NUM>, <NUM>, <NUM> and/or a circuitry <NUM> component such as the processor <NUM>. The plane P may be a plane formed to include the substrate <NUM>. In an embodiment, the plane P is perpendicular to the axis of rotation <NUM>. An annular construction of the substrate <NUM>, and rigid attachment of the strain measurement devices <NUM> as described above, provides for the disposition of a plurality of strain measurement devices <NUM> around the annular shape and about the torque input section. Such an annular construction also allows for the disposition of the strain measurement devices between the torque input section and the torque output section.

<FIG> is a block diagram of an exemplary power meter system <NUM> for a bicycle. The system <NUM> may be used alone to communicate with and/or control bicycle components or other devices. The system <NUM> includes circuitry <NUM> which includes at least one processor <NUM> and a memory <NUM>. In the illustrated embodiment, the circuitry <NUM> also includes a user interface <NUM>, a strain detection device interface <NUM>, and a communication interface <NUM>. Circuitry <NUM> may also include component connections and/or electrically connecting materials embedded in a substrate material. The system also includes at least one strain detection device <NUM> in communication with the strain detection device communication interface <NUM>. Additional, different, or fewer components are possible for the power meter system <NUM>. For example, the user interface <NUM> may not be included in a circuitry <NUM> and/or the power meter system. Also, components may be combined. In an embodiment, the power meter system is integrated with a component of a power train of a bicycle, such as a chainring or chainring carrier, for example as is described with respect to <FIG>, <FIG> and <FIG>.

The processor <NUM> may include a general processor, digital signal processor, an application specific integrated circuit (ASIC), field programmable gate array (FPGA), analog circuit, digital circuit, combinations thereof, or other now known or later developed processor. The processor <NUM> may be a single device or combinations of devices, such as through shared or parallel processing.

The circuitry <NUM> is operable to interpret a signal indicative of strain from deformation of an attached body from one or more of the strain detection devices <NUM> and determine a corresponding power transmitted between the torque input and the torque output section. For example, the signal may be communicated from the strain detection devices <NUM> to the processor <NUM> which may apply a conversion technique of the strain to a power transmitted across the body for a time period. Such a conversion technique may involve using the known material characteristics of the body, such as the modulus of elasticity and a known geometry of the body. Force values to cause amounts of strain measurable by the strain detection devices <NUM> may be known from these, or other, characteristics of the power meter system. For example, these values, or indications of these values, may be stored on a memory <NUM>. The measured strain values may be matched against these values by the processor <NUM> to determine an input force, and a resulting power over time transmitted by the body of the drive train.

The memory <NUM> may be a volatile memory or a non-volatile memory. The memory <NUM> may include one or more of a read only memory (ROM), random access memory (RAM), a flash memory, an electronic erasable program read only memory (EEPROM), or other type of memory. The memory <NUM> may be removable from the power meter system <NUM>, such as a secure digital (SD) memory card. In a particular non-limiting, exemplary embodiment, a computer-readable medium can include a solid-state memory such as a memory card or other package that houses one or more non-volatile read-only memories. Further, the computer-readable medium can be a random-access memory or other volatile re-writable memory. Additionally, the computer-readable medium can include a magneto-optical or optical medium, such as a disk or tapes or other storage device. Accordingly, the disclosure is considered to include any one or more of a computer-readable medium and other equivalents and successor media, in which data or instructions may be stored.

The memory <NUM> is a non-transitory computer-readable medium and is described to be a single medium. However, the term "computer-readable medium" includes a single medium or multiple media, such as a centralized or distributed memory structure, and/or associated caches that are operable to store one or more sets of instructions and other data. The term "computer-readable medium" shall also include any medium that is capable of storing, encoding or carrying a set of instructions for execution by a processor or that cause a computer system to perform any one or more of the methods or operations disclosed herein.

The power supply <NUM> is a portable power supply. The power supply may involve the generation of electric power, for example using a mechanical power generator, a fuel cell device, photo-voltaic cells, or other power generating devices. The power supply may include a battery such as a device consisting of two or more electrochemical cells that convert stored chemical energy into electrical energy. The power supply <NUM> may include a combination of multiple batteries or other power providing devices. Specially fitted or configured battery types, or standard battery types such as CR <NUM>, CR <NUM>, and/or CR <NUM> may be used.

The communication interface <NUM> provides for data and/or signal communication from the power meter system <NUM> to another component of the bicycle, or an external device such as a mobile phone or other computing device. The communication interface <NUM> communicates the data using any operable connection. An operable connection may be one in which signals, physical communications, and/or logical communications may be sent and/or received. An operable connection may include a physical interface, an electrical interface, and/or a data interface. The communication interface <NUM> may be configured to communicate wirelessly, and as such include one or more antennae. The communication interface <NUM> provides for wireless communications in any now known or later developed format. Bluetooth® and or ANT+™ standards may also, or alternatively, be used. In an embodiment, the communication interface <NUM> may be configured to transmit a signal indicative of a power determined from a measured strain of a body. Further, the determined power may be transmitted wirelessly.

The strain detection device interface <NUM> provides for data and/or signal communication from one or more strain detection devices <NUM> to the power meter circuitry <NUM>. The interface <NUM> communicates using wired and/or wireless communication techniques. For example, the interface <NUM> communicates with the strain detection devices <NUM> using a system bus, or other communication technique. The strain detection device interface <NUM> may include additional electric and/or electronic components, such as an additional processor and/or memory for detecting, communicating, and/or otherwise processing signals of the strain detection devices <NUM>.

The user interface <NUM> may be one or more buttons, keypad, keyboard, mouse, stylus pen, trackball, rocker switch, touch pad, voice recognition circuit, or other device or component for communicating data between a user and the power meter system <NUM>. The user interface <NUM> may be a touch screen, which may be capacitive or resistive. The user interface <NUM> may include a liquid crystal display ("LCD") panel, light emitting diode ("LED"), LED screen, thin film transistor screen, or another type of display. The user interface <NUM> may also include audio capabilities, or speakers.

In an embodiment, the user interface <NUM> includes an LED indicator. The LED indicator lights to indicate input of the commands or other actions of the power meter system.

Claim 1:
A power meter device (<NUM>) comprising:
a body comprising a torque input section (<NUM>) and a torque output section (<NUM>), the body configured to transmit power between the torque input section (<NUM>) and the torque output section (<NUM>), the -Etorque input section (<NUM>) adapted to be coupled to a crank arm (<NUM>), wherein the body is rotatable about a rotation axis (<NUM>), characterized in that, the torque output section (<NUM>) comprising an outer periphery comprising threads (<NUM>, <NUM>) adapted to be coupled to a chainring structure (<NUM>; <NUM>; <NUM>; <NUM>), wherein the threads (<NUM>; <NUM>) skip at least one thread; and
a plurality of strain measurement devices (<NUM>) coupled to the body, the plurality of strain measurement devices (<NUM>) configured to provide a signal indicative of strain detected in the body; and
circuitry (<NUM>) interpreting the signal and determining a corresponding power transmitted between the torque input section (<NUM>) and the torque output section (<NUM>).