WO2015095933A1

WO2015095933A1 - Improvements to cyclic cranked system data gathering

Info

Publication number: WO2015095933A1
Application number: PCT/AU2014/050452
Authority: WO
Inventors: David John Longman; Tom BASKOVICH
Original assignee: Breakaway Innovations Pty Ltd
Priority date: 2013-12-27
Filing date: 2014-12-24
Publication date: 2015-07-02

Abstract

A power meter for a crank arm (14) driven axle apparatus has electronics housed within or on the axle (12), and a force sensor (20) mounted on the crank arm (14) and optionally a force sensor on or in the axle (60). The power meter arranged to detect torque applied to an axle and/or crank arms connected to the axle. The crank arm and axle can form a unitary component. The electronics (16) can be provided as a module for insertion into the axle. A protective cover (44) can be provided over an opening in the crank arm to the electronics. Electrical connections to the force sensor(s) can be hard wired or connectable. The electronics can be provided within a housing (16a), which can include a battery (11) power supply, or the battery (11) can otherwise be provided within the axle/bottom bracket of a cycle. A rotational sensor (66) or encoder can be provided on the axle to detect characteristics of rotational motion of the axle. A second crank arm (14b) can be connected to a free end of the axle opposite the previously attached crank arm.

Description

IMPROVEMENTS TO CYCLIC CRANKED SYSTEM DATA GATHERING

FIELD OF THE INVENTION

[0001 ] The present invention relates to means and/or method for measuring the power input, torque and/or force(s) exerted through a cyclic crank system, for example, by a rider whilst riding a bicycle or a static exercise cycle.

[0002] The present invention also relates to the processes and methods used to provide useful output data in relation to the power input or output, applied torque and/or foree(s) exerted by a user.

[0003] The present invention also relates to the packaging of devices, such as for bicycles and other manually operated cyclic cranked systems. ,

BACKGROUND TO THE INVENTION

[0004] Although the present invention will often hereinafter be referred to in relation to bicycles, it will be appreciated that the present invention has

application in cyclic cranked systems where a crank arm or rotational action is applied to an axle, such as a static exercise cycle or manual winch having a crank driven axle.

[0005] A typical cycle includes a pedal crank set having a pair of pedal crank arms and a pair of associated pedals, each pedal being rotatably mounted to a distal end of its respective crank arm. The efforts of a rider are translated to power though application of force to the pedals which provide a motive torque to a chain wheel or other transmission device which in turn powers a wheel or wheels of the bicycle. [0006] Power-meters for bicycles are well known. Many different types of power-meters are available; examples including devices which measure and transform bicycle chain tension data into power readings, instrumented rear hub axles, instrumented chain-wheel devices, and instrumented crank axles and/or bottom brackets. A power-meter system normally has a force or torque sensing system that measures forces or torques applied by a rider (either directly or indirectly as explained further below).

[0007] Transformation or processing means takes signals or data from the sensing means and manipulates the data into parameters which are displayed on a display unit and/or stored in a memory unit for subsequent display and/or analysis,

[0008] One example of known prior art is given by United States patent publication US 2010/0093494 (also published by WIPO as PCT publication WO 2008/109914). A cartridge is arranged to be releasably retained in a hollow axle of a bicycle axle. Sensor elements within the cartridge give signals

corresponding to rotational angle of associated crank arms and/or torque applied thereto. The device measures pedaling forces through the axle, and is designed for use specifically with a crankset described in corresponding US patent publication US 2007/0182122 by the same applicant rather than being configured for general use and adaptability. It has been realised that left and right hand sensors close to each other within the cartridge placed within the axle may not provide accurate readings. Furthermore, no information is given about positioning sensors along the crank arms or how torque or power data might be obtained from such an arrangement.

[0009] Other examples of known power-meter systems include US patents numbers US 4,463,433 and US 5,027,303 which both describe a torque measuring system utilising strain gauges to measure the total torque input to a chain wheel by applying strain gauges to the pedal cranks, or to a chain wheel interface and a pedal crank. [0010] It has become common practice for bicycle riders to have display units that are capable of receiving and displaying various parameters relating to the riding activity. Many of these display units have the capability to display a cycling effort related power output. However, there are drawbacks restricting a

significant number of riders from adopting present power metering systems, for various reasons, including but not limited to, compromised aesthetics, sensitivity to water ingress, lack of accuracy, a requirement for regular re-calibration, the prohibitive cost and complexity of some of the available systems, or the fact that some of the systems impose a weight or other performance penally on the bike rider and therefore would not be favoured for race related events.

[001 ] ] Notably, prior international patent application PCT/AU2010/001594 by the present applicant (publication number WO 2011/063468 - the contents of which are herein incorporated in their entirety by reference) provides details as to how an arrangement, which places strain gauges into intimate bonded contact with a surface of the crank arm, would be packaged to provide a highly accurate, low weight, robust and water-proofed system that allows ready access to data and convenience of use by the rider. This prior international patent application also provides novel teachings to allow strain gauges to be applied directly to crank arm designs so as to provide the highest levels of accuracy and which are not constrained to be of a simple rectangular or square cross-section, thus allowing considerable functional and aesthetic design freedom in the design of suitable crank arms for power meter applications.

[0012] However, it has been realised that significant changes to the

positioning of, the number of components of, and/or the functionality of (bicycle or other cycle or crank arm operated axle systems) power meter devices/systems and related devices/systems, can improve one or more of water proofing, battery life, communications reliability and/or speed, and preferably reduce weight and number of components, part costs, assembly costs and also provide crank arm design freedom. It is with the aforementioned in mind that the present invention has been developed. [0013] It is to be noted that waterproofing of a cycle (such as a bicycle) power meter system is a non-trivial aspect of powermeter design and operation. This is particularly so in cases where the highest accuracy of power meter capability demands that the sensors (e.g. strain gauges) are directly and intimately bonded to the crank arm. In such cases this intimate bonding then requires that wiring connections and other components be embedded within the crank. High integrity water proofing of such systems then presents a practical challenge, which is conveniently addressed by the invention.

[0014] Providing cycle power meter systems as discrete modules, units or devices that are self contained, that are preferably part of an integrated assembly of components that are configured to remain together (such as a combined crank arm and axle assembly), or having minima! need for connections to other

(external) devices, is also beneficial. This reduces the number of connections that are otherwise vulnerable to corrosion, ingress of moisture, physical damage or loss of physical contact, any of which can result in signal loss.

SUMMARY OF THE INVENTION

[0001 ] Whilst the present invention will be described with reference to power meters, the term 'power meter includes torque meters for measuring torque applied to a crank driven axle apparatus, such as a bicycle, tricycle or static exercise cycle. Such power meters according to the present invention can also include measurement of rotational speed of the axle or derive rotational speed from time taken for the axle to rotate. Measurement of input torque and rotational axle speed or axle rotation time can be used to derive power input.

[0002] Torque is force that causes rotation around a central point or axis, such as an axle. Referring to the rotating axle, torque, also known as rotary force, is the product of the force multiplied by the length of the lever arm used to apply the force. The formula is: M = Fx I where M is the torque measured in newton-metre (Nm), Fis a force measured in newton (N) and / is the length of the lever arm measured in metres (m)

[0003] The following is a useful formula to demonstrate the relationship between torque and power,: where Power is measured in kilowatt (kW), Torque is measured in newton-metre (Nm) and Rotational speed In measured in revolutions per minute" (rpm): Power (kW) = Torque (Nm) x 2π x rotational speed ÷ 6000, (where 6,000 comes from 60 seconds per minute times 1000 watts per kilowatt).

[0004] With the aforementioned in mind, an aspect of the present invention provides a power meter device for an apparatus having a crank driven axle, the power meter device including electroniee to process signals provided from at least one force sensor for torque applied to a first end of the axle, and the electronics provided to process signals provided from another at least one force sensor for torque applied to a second end of the axle and/or to sense a combination of the sensed forces for torque applied to the first end of the axle and the second end of the axle.

[0005] The power meter may further include at least one axle rotational speed sensor. Preferably the rotational speed sensor is provided at least in part on the axle, such as a number of segments of a rotary sensor or encoder, or a magnet on the axle that passes static segments as the axle rotates.

[0006] A further aspect of the present invention provides a power meter device for a cycle, the power meter device including electronics provided on or within an axle of a cycle, preferably a bicycle.

[0007] The axle may be hollow to receive the electronics. The electronics may be provided as a discrete module for insertion into the hollow of the axle.

[0008] Preferably the power meter device is mounted within a bottom bracket of a cycle frame. [0009] A further aspect of the present invention provides a power meter device for an apparatus having a crank driven axle, the power meter device including electronics connected to at least one force sensor provided to sense forces associated with a non-drive side of the apparatus, and the electronics connected to another at least one force sensor to sense forces associated with a drive side of the apparatus and/or to sense a combination of forces associated with the non-drive side and the drive side of the apparatus.

[0010] Thus, the electronics may be common to force sensors providing force signals relating to both the non-drive side and the drive side of the cycle. A single electronics device reduces the number of power meter components, reduces complexity of components and reduces weight and space required. Reduction in the space required for the electronics means that the electronics may therefore be housed within the axle or on/in a crank arm, such as in a hollow axle or a recess/cavity in the crank arm.

[001] ] Preferably the electronics includes a signal processor arranged and configured to process signals received from the force sensors, and preferably to transmit the processed (or unprocessed) signals to a remote receiver.

[0012] The single electronics/processor device may derive a drive side input from a sensed non-drive side input and a total input. For example, one or more non-drive-side input sensors may be provided, such as at the non-drive side crank arm or the axle. And one or more total force sensors may be provided, such as on the spider. The total force input is a combination of drive and non- drive sides (i.e. left and right hand sides) from which the unknown force inputs by a user can be derived from subtracting the sensed non-drive-side force input from the sensed total force input.

[0013] A single processed or unprocessed signal output may therefore be provided from the electronics/processor, such as a wireless transmission or hard wired output to a remote device, such as a display, memory device or computer. [0014] The at least one first sensor relating to the drive side of the cycle may be provided in or on a drive side crank arm connected to an axle between the drive and non-drive sides. Alternatively, or in addition, at least one said first force sensor may be provided in or on a spider connecting the axle/crank arm drive side to a chainwheel for driving a chain of the cycle. Reference to chainwheel or chain is also taken to include flexible drive belts performing the equivalent function of a traditional chain drive.

[0015] It will be appreciated that the drive between the axle and the drive wheel(s) of the cycle may be provided by a drive shaft. For such applications, the drive side force sensor(s) may be provided within the drive train, such as in gearing or in the drive side crank arm.

[0016] The electronics may be electrically connected to at least one force sensor on a crank arm attached to the axle. The electronics may also or alternatively be electrically connected to at least one force sensor on or in the axle. The at least one force sensor on or in the axle may be within the hollow in the axle.

[0017] The axle and at least one said crank arm may be permanently attached to each other. For example, at least one particularly preferred embodiment of the present invention includes an integrated axle/spindle and crank arm assembly. It will be appreciated that such an integrated axie/spindle assembly preferably incorporates the drive side crank arm e.g. the chain wheel or right hand side (from the perspective of looking forward on the cycle). Thus, the crank axle, right hand crank arm, and one or more permanently attached or replaceable/upgradeable chainwheel(s} can be included.

[0018] Thus, the power meter may be comprised within a single assembly of crank arm and axle, with the electronics housed in the axle and one or more force sensors connected to the electronics. This provides a robust assembly less prone to failure, moisture and dirt ingress or interference from attempts at self- servicing by users.

[0019] It will be appreciated the axle can be slid into a bottom bracket of a cycle frame or into another housing, and the second crank arm attached to the free end of the axle. The second crank arm may also have a force sensor and/or antenna, with electrical connections provided by plug in assembly to connections to the electronics in the axle.

[0020] At least one rotational sensor may be operatively connected to the electronics. The rotational sensor(s) may include a portion on the axie and preferably a portion on the bottom bracket or housing around the axle. Thus, the portion on the axle and the portion on the bottom bracket or housing can rotate relative to one another when the axie rotates. The rotational sensor(s) may detect cadence, rotational speed, fluctuations in rotational speed of the axle. The rotational sensor(s) may provide such signals to the electronics for use in determining rider performance or ride characteristics.

[0021] The rotational sensor(s) may include a capacitive, inductive, magneto- resistive and/or optical sensing device to detect rotation. Preferably the rotational sensor(s) includes a passive sensing device i.e. unpowered, to help conserve battery power for the electronics. However, if preferred, one or more powered rotational sensor(s) can be employed, such as an optical pick-up.

[0022] It will be appreciated that multiple sensor elements or switches, such as reed switches, may be provided as part of or associated with the rotational sensor(s).

[0023] Another aspect of the present invention provides a power meter device for an apparatus having an axie and at least one crank arm operatively connected to the axle to rotatably drive the axie, the at least one crank arm including at least one respective force sensor arranged to detect force(s) applied to the crank arm during operation of the apparatus, the axle having a cavity, the device having at least one releasable electrical connection to the at least one force sensor, and wherein the device is at least in part slidably receivable into the ax!e cavity and the device is removably connectabte as a discrete module to and from the apparatus.

[0024] It is to be noted that a reference to a "force" sensor is intended to include sensors that are responsive to force inputs without necessarily directly measuring such force. For example, strain gauges when applied at suitable predetermined locations and orientations will produce electrical signals indicative of strain distortions, which, in combination with other parameters (such as the geometry and material properties of the associated crank arm) can be used to calculate an effective force at the pedal axle of such crank arm.

[0025] A further aspect of the present invention provides a power meter device for an apparatus having an axie and at least one crank arm operativeiy connected to the axle to rotatably drive the axle, the at least one crank arm including at least one first force sensor arranged to detect force(s) applied to the crank arm during operation of the apparatus, the axie including at least one second force sensor arranged to detect force(s) applied to the axle during operation of the apparatus, and wherein the axle houses electronics configured to process force related signals from the at least one first force sensor and/or the at least one second force.

[0026] Another aspect of the present invention provides a power meter device for an apparatus having an axle and at least one crank arm operativeiy connected to the axle to rotatably drive the axle, the at least one crank arm including at least one first force sensor arranged to detect force(s) applied to the crank arm during operation of the apparatus and/or, the axie including at least one second force sensor arranged to detect force(s) applied to the axle during operation of the apparatus, and wherein the axle houses electronics configured to process force related signals from respectively the at least one first force sensor and/or the at least one second force.

[0027] The power meter device may be provided as an assembly

incorporating a crank arm connected to the axle (either permanently or removably connected), with the axle housing the electronics. It will be appreciated that providing the axle and crank arm as a ready assembly, fitting of the device to a cycle becomes simplified with reduced number of components, but especially_., sealing and therefore component and reliability longevity is enhanced.

[0028] Alternatively, the power meter device may be provided as an axle arranged and configured to house the electronics connected to or connectable to the sensor housed in the axle. Thus, the axle may be hollow or otherwise have a cavity to house the electronics. The electronics may include a signal processor to process strain force signals received from the sensor(s).

[0029] The axle may be inserted into a bottom bracket of a cycle frame, and a second crank arm attached to the axle at a second end of the axle opposite to the first crank arm being at a first end of the axle.

[0030] A yet further aspect of the present invention provides a module for insertion into an axle of a crank operated apparatus, the module including electronics arranged and configured to receive and process signals received from at least one sensor.

[003] ] Preferably the at least one sensor includes at least one strain gauge providing signals relating to detected strain forces.

[0032] Preferably the electronics at least convert received analogue signals to digital signals. [0033] The module may include or be connected to an antenna to transmit processed signals to a remote location, such as a cycle display head unit for display of information relating to user input forces detected by the at least one sensor. The head unit may convert the received digital signals to a display format. The electronics may include a transmitter operatively connected to the antenna.

[0034] The module may include a battery power supply for the electronics and/or may include connections to an external battery power supply.

[0035] The electronics may be connected to a rotational sensor mounted at leats in part to the axle or other portion of a cycle drive train that rotates during use, such as a spider or crank arm.

[0036] The device may include a source of electrical energy housed in a housing of the device configured to be received into the axle cavity. The source of electrical energy may be or include a battery. The battery may be

rechargeable or replaceable in the device.

[0037] The device may include at least one processor arranged and configured to receive and process signals derived directly or indirectly from the at least one force sensor. The processor may be housed in a body of the device to be received into the axle cavity.

[0038] The at least one force sensor may be operationally attached to part of the axle, conveniently, within the hollow axle. Alternatively may be located within a first crank arm

[0039] Further electrical connection to at least one further force sensor provided may be provided on or in a second crank arm operatively connected to the axle. Preferably the further electrical connection passes through the axle to the second crank arm. [0040] The device may include at least one transmitter and antenna arranged to transmit data to a remote device, such as a remote display or computer.

[004] ] Fastening means may be provided to reieasably attach the device to one or both of the axle and the crank arm.

[0042] The device may further include a cover to protect the electrical connection passing through an opening in the crank arm to the at least one sensor in a cavity in the crank arm.

[0043] At least one seal may be provided preventing ingress of moisture to the part of the device received into the axEe cavity.

[0044] Reference to a 'device' in relation to the present invention is not to be taken as limiting the invention to a single component, rather, the term 'device' is to be taken to include multiple components.

[0045] Another aspect of the present invention provides a power meter system for a cycle, the system including a power meter device according to any one of the preceding claims, a pair of crank arms connected by an axle having a cavity to receive the device at least in part, at least one force sensor attached to surface inside a cavity in a said crank arm, a processor to receive and process data signals derived from the at least one force sensor, and a transmitter to transmit processed said data signals.

[0046] A further aspect of the present invention provides a cyclic cranked system data gathering system, the cyclic cranked system having at least one crank arm operatively connected to a crank axle, the at least one crank arm operable by a limb of a user, the data gathering system including at least one data gathering device located at the crank axle, and the at least one crank arm having at least one sensor, each said senor in communication with a said data gathering device, said at least one data gathering device configured to obtain data relating to force applied by the user through the respective crank arrn(s) and sensed by the respective at least one sensor.

[0047] At least one processor may be provided at the axle to process one or more signals from the sensor(s) relating to force (s) applied by the user through the respective crank arm(s). Preferably the at least one processor is mounted within the axle. For example, the axle may be hollow providing a cavity to receive therein the at least one processor.

[0048] It will be appreciated that having a single processor within the axle receiving data signals from sensors on a pair of opposed crank arms, such as provided on a bicycle, or from multiple sensors on a single crank arm, or combinations thereof, avoids the need for multiple processors. This saving not only reduces system weight and cost but can also allows a single processor to transmit processed data via a single transmitter to a receiver, such as a data display, memory device and/or computer.

[0049] It will further be appreciated that applying sensors to the crank axle is a convenient way to determine the forces/torques that are input via the left hand crank arm of a bicycle (following the conventional arrangement that the right hand side crank arm drives the chain set) without the need to modify the left hand crank for mounting or housing any sensors or electronics.

[0050] The data gathering system may include at least one transmitter in communication with the at least one processor. Preferably the at least one transmitter includes an antenna positioned such that the at least one transmitter transmits data from or adjacent to one or more ends of the crank axle. This may be where the crank arm meets the crank axle.

[005] ] The at least one antenna may project beyond an end of the crank axie, and may be provided with a protective cover. Having the antenna(e) at the end or at respective ends of the crank axle provides an acceptable line of sight for communication with a remotely positioned data receiver, such as a display or computer. For example, a display may be provided on the handlebar of a bicycle, and power/torque/cadence etc, data relating to the user's inputs may be transmitted from the data gathering device at the crank axle to the display via the antenna(e) at the crank axle end(s).

[0052] A power source may be provided in the crank axle. The power source may be a battery and/or may include a rotational driven electrical generator utilising the rotational motion of the cyclic cranked system to generate power. The rotational power generator may be used to charge a battery as backup power.

[0053] When multiple sensors are used, such as the force sensors on opposed crank arms of a bicycle, each sensor may be operatively connected to the data gathering device so that force data from each of the sensors is obtained and processed.

[0054] Alternatively, whilst the data gathering device might received force related data signals from multiple sensors, it is envisaged that in some

applications or embodiments of the present invention, only one set of data signals from one of the crank arms need be used. This arrangement, for example, might be used in a lower cost system where data from only one crank arm is utilised.

[0055] In yet another alternative, it is envisaged that in some applications or embodiments of the present invention, one set of sensors obtains data signals from one of the crank arms and another set of sensors obtains data from the axle of the crank system. Conveniently, the first set of sensors obtains data from the right hand (i.e. drive side) crank and the other set of sensors obtains data from the crank axle.

[0056] In the previous system described in the earlier patent application published as patent application WO 2011/063468 by the present applicant, data transfer can be by direct, line of sight, communication from one crank arm to the opposite crank arm because the data gathering device is housed on or in one of the crank arms. However, data transfer has been found to be problematic due to moving obstructions as the crank axle and therefore the crank arms rotate. In the example of a bicycle, the lower frame tubes and bottom bracket housing the crank axle, as well as the front chain set, all interpose periodically as the crank arms rotate, Consequently, housing the data gathering device in the crank axle and communicating from the sensor(s) to the data gathering device has improved communication reliability.

[0057] The present invention also allows for independent (preferably wireless) communication between each crank arm in circumstances that may warrant such independence of any direct wired connection between a left and a right crank arm. Indeed the present invention may be used in combination with the system described in the earlier patent application published as patent application WO 201 1/063468, the contents of which are incorporated herein in their entirety by reference, wherein one crank arm (for example the left crank arm) embodies all sensors and electronics within a cavity located in that arm whilst the other crank arm incorporates the present invention.

[0058] It has been found beneficial in the present invention that the at least one sensor may communicate data signals to the data gathering device at the crank axle via hard wires or wirelessly. In a hard wired arrangement, the at least one sensor is connected to the data gathering device by one or more wires passing along a portion of the crank arm to the crank axle, and into the crank axle to the data gathering device. This hard wired arrangement through the crank arm(s) to the data gathering device at the crank axle provides for more reliable data transfer from the sensor(s) on the respective crank arm(s) to the data gathering device. [0059] Alternatively, the at least one sensor may communicate wirelessly to the data gathering device via a transmitter provided on or in the crank arm (such as in a hollow or cavity of the crank arm).

[0060] Preferably at least one said sensor is intimately bonded to the crank arm in a predetermined location.

[006] ] Preferably each sensor is permanently connected to an Analogue to Digital ("A-D") converter which is placed in close proximity to the sensors so as to maximise signal strength and accuracy of sensor readings. An amplified digital signal may then be passed to the processor via a releasable electrical

interconnection.

[0062] The data gathering device at the crank axle may be sealed against ingress of dirt and/or moisture by one or more seals where the crank arm meets the crank axle. Such seals may be O-ring type seals, preferably of silicon rubber.

[0063] Preferably the battery within the crank axle may be user serviceable.

[0064] The data gathering device may be provided as a module that is received into a hollow crank axle. The module may be a single unit including the battery and processor and preferably an A-D converter. Furthermore, the sensor(s) may be pre-wired to the data gathering device. For example, the sensor(s) may be provided as a unit that attaches to or in the respective crank arm(s), with wiring going to the data gathering module inserted into the crank axle.

[0065] Preferably the at least one sensor and an associated A-D converter are 'potted' within a cavity of the crank arm thus providing a high integrity waterproofing solution. Such 'potting' is a process of enveloping an electronic assembly with a solid or gelatinous compound for resistance to shock and vibration, and for exclusion of moisture and corrosive agents. Thermo -setting plastics (such as polurethane) or silicone rubber geis are often used. In regard to one or more embodiments of the present invention, the at least one sensor and an associated A-D converter may be protectively sealed within a recess or hollow in the crank arm by such 'potting' whereby the at least one sensor and an associated A-D converter are importantly sealed against ingress of moisture and shock protected.

[0066] Preferably a releasab!e electrical interconnection is provided on the crank arm in a region separate from the cavity which houses the at least one sensor and associated A-D converter. Conveniently, a protective covering may be provided over the sensor(s) and associated electronics on the crank arm(s). This may be by way of a synthetic/plastic material coating or pre-formed cover. The additional cover may be provided to cosmetically cover and/or protect the potted components. The cover may form part of the data gathering device, such as by carrying electrical connections to the potted electronics.

[0067] The protective cover may include electrical connections to transfer data signals between electronics in or on the crank arm relating to force sensing to the data gathering device.

[0068] Electronics for receiving sensed force data from the at least one sensor may be housed in the respective crank arm or may be housed as part of the data gathering device.

[0069] The electronics may include a transmitter or transceiver to

communicate data between the data gathering device and a remote device, such as a display.

[0070] A further aspect of the present invention provides a cycling force detecting system for a hollow crank axle and crank arm assembly, the crank arm supporting a force sensor to, in use, detect forces applied to the crank arm, and a data gathering device arranged and configured to be received into the hollow crank axle.

[007] ] The cycling force detecting system may be provided as a kit of parts including the data gathering device and at least one said crank arm, preferably a pair of crank arms.

[0072] The kit of parts may be provided as a crank axle including a pre- installed fitted data gathering device, and a pair of crank arms ready to mount to the respective ends of the crank axle. The kit of parts may be provided for a bicycle.

[0073] If a cycling related event is sensed (e.g. a cadence signal or forces through the sensor(s), the device or system may activate from a low power consumption standby state. In this way, the device or system does not shut down completely (which therefore requires a start-up time which causes data processing and output delays), rather, the device or system stays on permanently in a mode to immediately process and transmit data. This avoids delays in establishing communications with a display unit or data acquisition system . The device or system does not have to 're-boot' itself, retrieve information from memory and only then proceed to enter a state that data acquisition and transmission became possible. This allows for very low battery power

consumption in the standby state whereby battery power consumption is negligible thereby not requiring a sleep or shutdown mode.

[0074] One or more forms of the present invention provide(s) a discrete (modular) housing for a key component of a cycle power meter system.

[0075] The housing is preferably retained in a hollow axle shaft of the cycle when in use, and preferably contains a microprocessor and wireless

communications components to process and transmit data gathered by the device from one or more force sensors provided on at least one of the crank arms, In this form, this housing can be referred to as an "active" module in that it contains active electronic elements, such as the microprocessor.

[0076] The device can be sealed to provide robust and water proofing interfaces to seal the power meter components whilst also providing for user a replaceable power source within the housing. The present invention provides the ability to use well known and field proven water sealing techniques, such as the use of "Q" ring seals and potting materials for electronic components,

[0077] Torque contribution applied to one end of the axle (e.g. from a left hand side or non-drive side ~ such as from a crank arm) may be derived by the torque measurements taken via at least one sensor mounted at the axle (e.g. mounted at least in part to the axle).

[0078] Torque contribution from the second end of the axle (e.g. a right hand side or drive side - such as a second crank arm) may be derived by deducting the contribution of the one end of the axle from the measurements taken via at least one other sensor arranged and configured to sense total torque being transmitted to a drive output, such as a cycle drive system - e.g. which may be a bicycle drive chainwheel.

[0079] Such torque contributions may be converted to power contributions as described hereinabove with reference to cadence, rotation or rotational speed input.

[0080] The present invention in one or more forms also allows for the use of a "dummy" or "passive" module which can be partnered with an "active" module. This dummy or passive module facilitates the convenient and easy connection of a sensor crank arm to the active module which itself is connected to the sensors in the other crank arm. This dummy module provides the waterproofing and wiring connections between its associated crank arm and the active module, but otherwise does not house any active electronic components. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Figure 1 shows a perspective of a device in the form of a module according to an embodiment of the present invention interfacing with electronics and sensors.

[0082] Figure 2 shows a bottom perspective of the module of Figure 1 showing contacts for electricatiy connecting to electronics and another dummy or passive device forming part of a system according to an embodiment of the present invention.

[0083] Figure 3 shows the module of Figure 1 mounted to a crank arm with connection to a sensor arrangement within a cavity in the crank arm.

[0084] Figure 4 shows an alternative view of the embodiment shown in Figure 3, revealing the contacts from the module through an opening in the crank arm.

[0085] Figure 5 shows a sectional view of an embodiment of the present invention utilising an active module for one crank arm and a passive module for an opposite crank arm.

[0086] Figure 6 shows an embodiment of the present invention provided in relation to a bicycle crank set-up.

[0087] Figure 7 shows an alternative embodiment of the present invention provided in relation to a bicycle crank set-up.

[0088] Figure 8 shows a further embodiment of the present invention with sensor arrangement on an inner surface of the crank arm. [0089] Figure 9 shows an alternative embodiment of the present invention with the sensor arrangement mounted in a recess of the crank arm with the data gathering device module connecting to the sensor arrangement via connections under a protective covering.

[0090] Figure 10 shows an externally recessed crank arm and also a data gathering device with weatherproof cover provided as an integrated module according to an embodiment of the present invention,

[0091] Figure 1 1 shows a section through a pair of opposed crank arms each attached to a respective end of a crank axle, the crank axie housing a data gathering device according to an embodiment of the present invention.

[0092] Figure 12 shows a sectioned perspective view of part of a bike frame including a bottom bracket housing a hollow crank axie supporting opposed crank arms, and an embodiment of the present invention provided thereon.

[0093] Figure 13 shows a crank axle and one crank arm with an embodiment of the present invention.

[0094] Figure 14 shows a crank axle and one crank arm with an embodiment of the present invention including force sensing electronics packaged in the crank arm.

[0095] Figure 15 shows an exploded section of an embodiment of the present invention for dual crank arm force sensing.

[0096] Figure 16 shows an assembled view of the embodiment shown in figure 15. [0097] Figure 17 shows a crank axle with single crank arm sensing set-up with force sensing electronics packaged into a hollow in the crank arm, a cadence/rotation sensor at a distal (pedal) end of the crank arm, and a data gathering device with protective cover and electrical connection to the In arm' electronics partially removed/assembled, according to an embodiment of the present invention.

[0098] Figure 18 shows an assembled view of the embodiment shown in figure 17.

[0099] Figure 19 shows an alternative form of the present invention providing an instrumented axle and crank arm with sensor assembly.

[00100] Figure 20 shows an alternative form of the present invention providing force sensors in alternative/optional positions, such that at least two force sensors provide differing force signals to a shared electronics device for signal processing and/or reporting remotely.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0010] ] Embodiments of the present invention will hereinafter be described with reference to the accompanying drawings.

[00102] Figure 1 shows an embodiment of the present invention including a data gathering device 16 incorporating a housing 16a to be received into a hollow axle of a crank set. The housing 16a contains a battery 11 to power the device and a processor to receive and process signals from a sensor arrangement 20. The sensor arrangement in this embodiment includes a pair of strain gauges 20a1 , 20a2 arranged and configured to be mounted internally of a crank arm (not shown). The strain gauges would be attached to respective opposed walls within a hollow or recess in the crank arm. The location and orientation of the strain gauges may conveniently be in accordance with the teachings of the applicants co-pending patent application PCT/AU2010/001594, the contents of which are herein incorporated in their entirety.

[00103] The strain gauges detect tension and compression forces arising form minute flexing of the crank arm. These signals are received by electronics 21 also within the hollow or recess of the crank arm.

[00104] One or more embodiments utilise an analogue to digital (A-D) converter to interface between the strain gauges and the processor within the housing. The A-D converter can receive the minute signals from the strain gauges and apply a gain (amplify) as well as sample the received signals and convert them to a digital data stream to the processor,

[00105] It will be appreciated that the processor can be provided as part of or locally connected to the sensor arrangement 20. In which case, the battery 1 1 will connect to the processor and sensor electronics via connections from the housing 16a through the arm 44.

[00106] Figure 2 shows a perspective view of an embodiment of the present invention as a data gathering device including a discrete module as shown in figure 1 . The device includes a housing 16a for a battery 1 1 and processor 21 . The battery 1 1 provides power to the processor. Internal wire connections (not shown) extend from the processor via the arm 44 to at least one electrical connector or at least one electrical contact 50.

[00107] The housing includes a weatherproof seal 17 to prevent ingress of dirt and/or moisture to the space between the housing and the hollow centre of the axle 12. The seal can be an O-ring type seal, which preferably sits in an annular groove around the housing towards the arm. The arm may include one or more fastening points, such as fastening points I 9a,19b, for one or more threaded or other fasteners to secure the arm 44 to a crank arm 14 (and therefore hold the device with the housing 16a within the hollow crank axle). [00108] The device 16.includes electrical contacts 13 at a distal end thereof, These contacts enable the device to electrically connect to a second sensor arrangement in a second crank arm. Thus, signals from corresponding strain gauges 20b1 , 20b2 (not shown) can be supplied to a corresponding A-D converter for that second crank arm, and then provided to either the processor in the housing of the device or provided to a second processor.

[00109] When a second set of strain gauges is not required or not in use, the second crank arm may have a dummy device or plug inserted to simply blank off the open end of the hollow crank axle and corresponding connection to the hollow or recess in the second crank arm. In such an arrangement, the electronics assembly may not be provided (though the strain gauges may be attached to the inside surfaces of the hollow or recess in certain applications, e.g. to simplify supply of crank arms that have strain gauges pre-positioned in case the second crank arm is intended to be used for forces to be input to the system at a later date),

[00110] Figure 3 shows the data gathering device 16 provided as a module mounted to a crank arm 14. Fasteners can be released at the fastening points 19a,19b, such as by removing one or more Allen bolts, hex screws etc. The housing can then be withdrawn from the hollow axle. This disconnects the electrical connection between the contacts 50 and cooperating connections to the electronics assembly (the A-D converter) within the hollow/recess of the crank arm shown in phantom. The housing being removable from the crank arm and axle allows the battery 11 to be replaced or recharged. It is also extremely beneficial for in situ replacement of the device should the original one fail or become damaged, or if a device upgrade is required. The device can also be conveniently tested and calibrated during manufacture as the contact points on the crank arms can be accessed during calibration with the device removed.

[001 ] 1] Figure 4 shows a view of the cavity (hollow or recess) in the crank arm revealing where the contacts 50 of the arm 44 of the device 18 are available for contact with connections on the A-D converter (A-D converter removed in this view). Strain gauges 20a1 and 20a2 are shown on either side of the cavity.

[00112] The cavity can be 'potted' with a sealing material, such as,

polyurethane, when the electronics assembly is received in the cavity. This seals the electronics from ingress of moisture and dirt and renders them weatherproof. An additional cover can be applied to the cavity to ensure weatherproofing and for aesthetic appeal. The electronics may have a contact zone, such as pad, with electrical contacts corresponding to the contacts 50 from the device. The A-D converter may be provided on a printed circuit board (PCB) with the contact zone.

[00113] Figure 5 shows a cross section through a device according to an embodiment of the present invention. The embodiment shows an active module 16a to electrically connect with a passive module 60, The active module has the processor and battery 1 1. The passive module does not include a processor or battery 11 , but includes contacts 50b corresponding to contacts 50a on the active module ready to connect to a sensor assembly in the crank arm (not shown). Thus electrical connection is provided for transferring data between a sensor assembly in each crank arm when provided. The passive module does not do any processing. Processed data is transmitted from the active module via an antenna 34 adjacent the processor 33.

[00114] An alternative set-up includes a dummy cover instead of the passive module housing. The dummy cover has no electrical connections to the active module but still seals or covers over openings into the crank arm 14b and seals the end of the axle.

[00115] Figure 6 shows a portion of a crank set-up for a bicycle incorporating an embodiment of the present invention. Figure 7 shows portions of frame tubes meeting a bottom bracket housing the crank axle and data gathering device. [001 1 6] A crank axle 12 is connected to a crank arm 14. Only one crank arm and associated pedal are shown in this embodiment in Figure 6. However, it will be appreciated that a corresponding and opposite facing crank arm 14b and pedal will be disposed on the opposite end of the crank axle 12, as shown in Figure 7.

[001 1 7] This embodiment in Figure 6 does, however, demonstrate the applicability of the present invention to single crank arm applications, such as manually operated winches and hoists e.g. for marine use. Forces applied to the single crank arm can be detected by the sensor arrangement and communicated to the data gathering device at the crank axle for processing. Processed data is then transmitted via the transceiver in the data gathering device and antenna 28.

[001 1 8] The crank axle 12 includes a cavity 12a housing a data gathering device 16. The data gathering device is connected by wires 18 to a sensor arrangement 20 disposed and positioned on the crank arm. The sensor arrangement can include electronics to resolve forces in the crank arm applied by a user and sensed by the sensor(s).

[001 1 9] In the twin crank arm set-up as shown in Figure 7, a sensor arrangement 20a,20b is shown on each respective crank arm 14a,14b connected to the data gathering device via respective wires 18a,18b.

[00120] The data gathering device communicates via a transmitter antenna 28 (Fig 7) through pathway 26. The antenna is protected by a cover at the end of the crank axle where the crank arm joins the crank axle. The antenna transmits (T) processed data to a display e.g. at the handlebars or to a data logger or remote device, such as a computer.

[00121] The cavity in the crank axle houses the data gathering device with its power supply, preferably a battery 1 1 (which can be a non-user serviceable component). The data gathering device may be a complete module inserted into the crank axle. Thus, a standard hollow crank axle can be manufactured ready to accept a data gathering device module with onboard power supply and

transceiver, which module may be pre-wired or ready for connection to the sensor arrangement.

[00122] Cadence and/or rotation rate can be determined using one or more reed switches 34,36 which pass corresponding magnets 30,32 mounted on the frame. The present invention need only use only one of the reed switch and magnet arrangements.

[00123] Other means to generate, or enable the determination, of a cadence rate can be used, and the present invention is not limited to any particular means, or the inclusion of any means, of generating a cadence signal.

[00124] Figure 8 shows an embodiment of the data gathering system of the present invention with the data gathering device 18 arranged to be received into a hollow crank axle. The data gathering device is hard wired to the sensor arrangement 20 via wires and connections passing through the hollow crank arm.

[00125] It will be appreciated that the data gathering device is provided, in this embodiment, as a plug in module whereby the data gathering device is a one piece unit with combined transmitter, battery 1 1 , processor and antenna, all housed in a sealed housing with a protective cover 38 which also carries hard wire connections to connect to the wiring through the hollow or recess 40 in the crank arm and thence to the sensor arrangement 20 mounted on the upper surface (in the view shown in Figure 8} of the crank arm.

[00126] As shown in Figure 9, the outer face 42 of the crank arm can include a hollow section or a recess 40 over which an arm portion 44 of the data gathering device module provides a cover and weatherproof seal (being an Ό" ring sea! not shown) as part of an all in one unit/module. [00127] The data gathering device may include one or more physical connections 13 to connect to a sensor arrangement from the opposite crank arm. Thus, the module may be set-up for single crank arm operation through connection to a sensor arrangement on the antenna side of the module, or a dual crank arm set-up by connection to the second crank arm (as shown in Figure 7).

[00128] Figure 10 shows a left hand side crank arm with reference axes marked and the crank arm having a cavity or recess in an external face thereof. This crank arm cavity or recess 40 is arranged to receive electronics associated with the sensor arrangement for that crank arm. The data gathering device 16 forms part of an integrated module including the antenna housed under a weatherproof cover that, in use, forms a low dome at the end of the crank axle.

[00129] A sensor arrangement in the form of a strain gauge set 20a is shown mounted to the inner upper surface in this view with a further strain gauge set 20b, mounted on the inner lower surface on the opposite side of crank arm 14. Torque about the X axis i.e. identified as M_x caused by downward/upward force on the pedal (not shown) can result in compression-tension forces along the crank arm because the proximal end (crank end) of the crank arm is essentially fixed and the pedal axle acts as a cantilever. Likewise, sideways forces (in the Z direction) also set up compression-tension forces in the crank arm. It is noted that the use of pedal with bearings will result in zero or minimal torques being generated about the Z axis (i.e. Mz = 0 or is negligible). One or more of these forces can be resolved by the processor in the data gathering device and useful information transmitted to the remote receiver for display. It is a well understood mechanical principle that it is only the forces in the Y axis, i.e. Fy (also referred to as the tangential force) that produce a power output when cycling. The other forces and torques may however also be measured by the appropriate application of sensors. For the purposes of the present embodiment, the location, orientation and electrical connection design of the strain gauges (e.g. the use of a

Wheatstone bridge circuit) is such that there is only an output signal in relation to Fy. [00130] The present invention may include embodiments that incorporate processors and circuitry that perform fast-Fourier-transformations (FFT) on sensed strain gauge data and communicate a selected number of terms of the FFT to a display unit This provides an efficient method of communicating crank- angle based power and/or torque data to a display unit or to a memory unit. Such data may be processed to provide detailed analysis of the pedaling action of a rider.

[00131] The present invention may include embodiments that compensate for temperature. Thus, the data gathering device may obtain or be provided with values relating to temperature of one or more crank arms and/or temperature fluctuations affecting the system. Temperature values may be utilised to modify, calibrate and/or maintain accuracy of signals or data into or out of the data gathering device or may be used with the data set transmitted from the data gathering device. More specifically, the present invention contemplates calibration values which take into account any temperature related changes of the sensors and/or the base material of the crank arms to which the sensors are applied. In this way not only will the calibration account for strain values which are generated as a result of temperature changes but also will account for how these strain values changes when the base material of the crank is at different temperatures (e.g. changes to the Young's modulus of the base material).

[00132] Each cran k arm and/or data gathering device may be nominated to have a unique identifier.

[00133] Information relating to positioning of the sensor arrangements, such as strain gauge orientation relative to the crank arm, can be obtained from WO 201 1/063468 the contents of which are incorporated herein by reference in their entirety.

[00134] In use, the data gathering device is mounted into a cavity of a crank axle, such as the crank axle of a bicycle. When a torque is applied to each of the crank arms, a strain gauge sensor arrangement on one or more of the crank arms provides data signals to a processor housed in the data gathering device in the crank axle. Electrical connection between the sensor arrangement and the processor is provided by hard wire connection. St will be appreciated that, because the crank arm and crank axle rotate together, no slip ring or other rotatable electrical connection needs to be provided.

[00135] Processed data is transmitted via a transceiver in the data gathering device and an antenna to a remote receiver,

[00136] The antenna may project out from an outer surface of an end of the crank axle and the crank arm connection to give a line of sight transmission connection to a receiver.

[00137] Preferably the antenna is under a protective, weatherproof cover,

[00138] The data gathering device can be provided as a single module with a housing that inserts into the crank axle cavity and has the antenna and the senor arrangement already connected. Alternatively, the data gathering device can electrically connect to a sensor arrangement mounted on the crank arm.

[00139] User applied forces to the crank arm(s) can be resolved in terms of compression, tension and shear forces in the crank arms, and cadence and rate of rotation can be determined by sensing characteristics of rotation of the crank arm(s). This data can be processed to determine power and energy, force, rate and ride characteristics etc. of the user,

[00140] Figure 1 1 shows a section a pair of crank arms 140,14b, each arm attached to a respective end of a hollow crank axle 12. A data gathering device 16 is received into the hollow crank axle. An end of the data gathering device is connected to a connector 50b arranged to pass into an opening 52b in one of the crank arms. This connector provides electrical connection to electronics (40, Fig 12) housed in a hollow or recess 22b in the crank arm. The electrical connection between the connector and the data gathering device is covered by a protective cover 44b, which is preferably weatherproof and impact resistant. The protective cover may support branding.

[00141] In the embodiment shown in figure 11 , the other of the opposed crank arms 14a receives a dummy cover 44a with dummy connector 50a. That is, there is no electrical connection and no electronics housed in this second crank arm. However, the crank arm 14a still has a hollow or recess 22a, and the opening 52a ready to receive and connect an electronics package to the data gathering device. This can be provided as an upgrade step to take the single sensor package system utilising force sensing electronics in one crank arm up to a dual electronics package with sensing provided on each crank arm.

[00142] The embodiment shown in figure 12 includes provision for electronics 40 housed in each crank arm, with a respective cadence/rotation sensor 34 on a distal end of one or both arms. Each cadence/rotation sensor is electrically connected to a respective electronics module 40. However, it will be appreciated that dual cadence/rotation sensors may be used, one on each crank arm, and electrically connected to just a single electronics module. The electronics module 40 comprises and A-D converter and provides signal outputs to the data gathering device 16.

[00143] Figure 13 shows an embodiment of the present invention with strain gauge sensors 20a, 20b mounted on the crank arm 14. The data gathering device 16 is received into the hollow crank axle 12 after the crank arm 14 is mounted onto the end of the crank axle. The connector 50 on an end of the cover 44 is plugged into the opening in the crank arm so that a physical electrical connection can be made with the electronics module 54 housed in the crank arm. The strain gauge sensors 20a, 20b also connect to the electronics module. [00144] Figure 14 shows an alternative view of the electronics module with a cadence/rotation sensor 34 electrically connected.

[00145] Figure 15 shows an exploded section of the general components of an embodiment of the present invention.

[00146] Figure 16 shows a similar section with the same components assembled. This is a twin electronics module arrangement, with each crank arm 14a, 14b having its own electronics module 54a,54b providing respective force data to the data gathering device 16. Each crank arm also includes a

cadence/rotation sensor 34, although technically only one of these sensors is required. For ease of manufacturing and inventory costs, and a degree of redundancy in ensuring a cadence signal is generated, a sensor 34 may be included in each crank arm,

[00147] Figures 17 and 18 show a general arrangement of an embodiment of the present invention packaged into a crank axle and single crank arm. The protective cover 44 provides weatherproof and impact protection to the

electronics and electrical connections in the crank arm and also helps to seal access to the data gathering device and thereby prevent ingress of

water/moisture and dirt.

[00148] The hollow or recess 22 in the crank arm 14 may include an additional cover or seal, such as a polymer, which may embed the electronics module 54 in a protective material, such as a settable polymer.

[00149] According to at least one preferred embodiment, the present invention provides a power meter for a bicycle by detecting force applied to one or more crank arms and processing the force related data signals in a data gathering device housed at the crank axle, and then communicating the processed data to a display or other remote device. [00150] However, it will be appreciated that the present invention is also applicable to other embodiments, such as winches and hoists used in marine applications where a winch or hoist crank arm is manually operated. Force applied to the crank arm can be detected, measured, and reported. This can help show how efficiently the winch or hoist is being used, or how efficient the winch or hoist itself is at translating applied force into action.

[0015] ] A power meter device of the present invention preferably includes electronics including a processor to process signals provided from at least one force sensor associated with torque applied to a first end of the axle. In addition, the electronics can also process signals provided from another at least one force sensor associated with torque applied to a second end of the axie and/or to sense a combination of the forces associated with torque applied to the first end of the axle and the second end of the axle (total torque input to the axle for a given revolution of the axle).

[00152] The at least one force sensor can be provided for a non-drive side of the axle of a cycle, such as in or on a non-drive side crank arm. The other at least one force sensor can be provided on a drive side of the axle, such as in or on a drive side crank arm or on a spider associated with the drive side.

[00153] It will be appreciated that drive output may be as in a bicycle, with a chain or belt or shaft drive associated with a left or right hand side of the cycle. Typically bicycles have their drive side on the right hand side (with respect to looking forward).

[00154] A central drive output, such as a drive band from an axle of a static exercise cycle to a flywheel or friction wheel can also be instrumented within the scope of the present invention.

[00155] Torque input to the axle can be detected by the force sensors as strain signals from strain gauges mounted on or in the crank arms driving the axle. At least one strain gauge can be mounted to the axle to detect strain which the electronics can use to determine torque applied to the axle.

[00156] The at least one force sensor sense(s) forces associated with a non- drive side of the apparatus, and the another at least one force sensor sense(s) forces associated with a drive side of the apparatus and/or sense(s) a

combination of the forces associated with the non-drive side and the drive side of the apparatus.

[00157] Figure 19 shows an alternative arrangement of the present invention wherein a hollow crank axle 12 houses a data gathering device 16.

[00158] The device 16 houses electronics electrically connected to at least one force sensor 20 (such as a strain gauge) mounted to a crank arm 14 (preferably being the drive/chainwheel side crank arm 14a). Preferably the at least one force sensor is mounted in a hollow or recess 22 within the crank arm.

[00159] Preferably the at least one sensor 20 on the crank arm may be hard wired to the electronics of the device 16. In such a set-up, the crank arm and axle would ideally be permanently or semi-permanently coupled together or formed as a single piece component. Thus, the assembly of the crank arm and axle, and the instrumented device 16 within the axle, would be intended to remain permanently together for normal use, and not intended to be user serviceable or for disassembly by a user. In the case of semi-permanent assembly, servicing and disassembly may be available via an authorised agent. By semi-permanent assembly is meant that the assembly is not readily intended to be disassembled by a user because electrical connections will be hard wired (soldered) and specialised tools ay be required to separate the crank arm from the axle that accommodate the presence of the electrical connections also present.

[00160] In the embodiment shown in Figure 19, a protective cover 44 covers over (and preferably provides a weatherproof seal against ingress of moisture and dirt) the electrical wire connections 56 between the sensor(s) 20 and the electronics.

[0016] ] An antenna 34 is also operative!/ connected to the electronics within the device 16. The antenna projects a small amount out from the outer surface of the crank arm. This is preferable when the crank arm is of metal. The antenna may still be covered by the cover to provide weather and impact protection. For composite or carbon fibre crank arms or other non-metallic crank arms, the antenna may be at or below the out surface of the crank arm,

[00162] It will be appreciated that the central portion 12a of the axle 12 may be housed within a tube housing 64, The axle has first and second opposed ends 12b, 12c. Either end may be termed the first end. The opposite end thereto may be termed the second end.

[00163] The axle may alternatively be mounted directly into a bottom bracket of a cycle frame. Alternatively, the axle within the tube housing 64 may be mounted into the bottom bracket. The axle is, of course, mounted by bearings for rotation when driven by the crank arm(s).

[00164] One of the first and second ends of the axle may be permanently or releasably attached to a said crank arm, and a spider may preferably be attached thereto.

[00165] One or more rotation sensors 66 provides an output relating to one or more detected rotation characteristics of the axle, which characteristic(s) can include one or more of cadence and variation in rotational speed of the axle.

[00166] It will be appreciated that force signals from the crank arm sensor(s), force signals from the axle sensor(s), and rotation characteristic signals from the rotation sensor(s) can be used by the electronics to determine characteristics of power applied through the crank arms to the axle and therefore to the cycle. [00167] The electronics can include a transmitter to transmit pre or post processed signals via the antenna to a remote location, such as a display mounted on handlebars of the cycle or to a computer, tablet or smartphone or other portable computing or display device.

[00168] In the embodiment shown in Figure 19, the one or more rotation sensors 66 includes a magnet 68 attached to the housing or inside surface of the bottom bracket, and a rotational pickup 70 on the axle. The rotational pickup can have a number of elements that rotate with the axle and pass through the magnetic flux from the magnet, causing an electrical pulse signal for detection by the electronics. The frequency of pulses relates of the rate of rotation of the axle.

[00169] Other rotation sensors, such as optica! sensors can be used. The rotational pickup may be formed as part of the axle or may comprise one or more elements attached to the axle, such as a ring of elements individually or as a unit applied around the axle. The elements may be provided on a ring component slid onto and affixed to the axle, such as by interference fit or bonding.

[00170] The rotational pickup or sensor can be termed an 'encoder', and it may be used to measure distance travelled by calculation from the number of rotations of the axle and the number and/or spacing of the elements or pulses, and preferably including a known gear ratio between the axle and the drive wheel of a cycle and/or circumference of the drive wheel, such as the circumference of the rear wheel of a bicycle (or the electronics including calculation algorithms to derive the gear ratio and/or wheel circumference from stored data or data provided from a remote source).

[00171] The data gathering device 16 may be inserted into the axle as a module. Electrical connections to the module may be provided by wired plug in connections to terminals on the module and/or connected to the crank arm and/or axle force sensor(s). [00172] Figure 20 shows an embodiment of the present invention with a spider 72 and drive side crank arm 14a assembly/unit for a cycle. The spider need not be permanently attached to the driver side crank arm and need not be

permanently attached to the axle 12. For example, the spider can be removably attached to the drive side crank arm or permanently attached/be formed as one with the drive side crank arm. Alternatively or in addition, the spider can be removably attached to the axle or permanently attached/be formed as one with the axle. It will be appreciated that the spider and drive side crank arm can be integrated as a single unit, for example, manufactured as a single moulded, cast and/or machined component, as shown in Figure 20.

[00173] One or more force sensors 74 can be provided in or on one or more of the 'arms' 76 of the spider 72. The spider shown in Figure 20 has five arms. Fewer or more arms may be utilised. Each of the arms 76 of the spider 72 has an aperture for receiving a fastener 78 to retain a chainwheel or chainwheel set to the spider for engagement with a chain to drive a wheel/axle of the cycle.

[00174] In the configuration shown in Figure 20, the spider is preferably permanently attached to the axle 12 to accommodate hard wire electrical connection of the force sensors 74 to the electronics package 16 and avoid introducing a releasable (plug-in) electrical connection between the axle and the spider.

In operation, the torque contribution from the left (ie non-drive side) crank arm 14b may be derived by the torque measurements taken via sensors 60 at the axle. The torque contribution from the right (ie drive side) crank arm 14a can be derived by deducting the left crank arm contribution from the measurements taken via sensors 74 (which sensor the total torque being transmitted to the bicycle drive system). These torque contributions may be converted to power contributions as described hereinabove with reference to cadence input.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A power meter device for an apparatus having a crank driven axle, the power meter device including electronics to process signals provided from at least one force sensor for torque applied to a first end of the axle, and the electronics provided to process signals provided from another at least one force sensor for torque applied to a second end of the axle and/or to sense a combination of the sensed forces for torque applied to the first end of the axle and the second end of the axle.

2. A device of claim 1 , wherein the at least one force sensor sense(s) forces associated with a non-drive side of the apparatus, and the another at least one force sensor sense(s) forces associated with a drive side of the apparatus and/or sense(s) a combination or total of the forces associated with the non-drive side and the drive side of the apparatus,

3. A device of claim 1 or claim 2, wherein the electronics of the power meter are provided on or within the axle.

4. A device according to any one of claims 1 -3, and wherein the apparatus has at least one crank arm operatively connected to the first or second end of the axle to rotatably drive the axle.

5. A device according to claim 4, including a said crank arm operatively connected to each of the respective first and second ends of the axle.

6. A device of claim 4 or 5, the at least one crank arm including a said at least one force sensor arranged to detect the force(s) applied to the crank arm and/or axle during operation of the apparatus.

7. A device of claim 3, the axle having a cavity or hollow arranged to receive the electronics.

8. A device of claim 4, 5 or 6, the device having at least one releasable electrical connection to a said at least one force sensor on a said crank arm.

9. A device of claim 3, wherein the device includes the electronics in a housing that is at least in part slidably receivable into the axle cavity or hollow,

10. A device according to any one of the preceding claims, the device including the electronics removably connectable as a discrete module to and from the axle of the apparatus.

11. A device according to any one of the preceding claims, the device including or connected to a source of electrical energy.

12. A device according to claim 11 , the source of electrical energy for housing within or on the axle or a bottom bracket of a cycle frame of the apparatus..

13. A device according to claim 12, wherein the battery is housed with the electronics in a housing.

14. A device of claim 12 or 13, wherein the source of electrical energy includes a battery.

15. A device according to any one of the preceding claims, the electronics of the device including at least one processor arranged and configured to receive and process signals derived directly or indirectly from a said at least one force sensor.

16. A device according to claim 4, including further electrical connection to at least one said force sensor provided on or in a said crank arm operatively connected to the axle.

17. A device according to claim 16, wherein the further electrical connection passes through the axle.

18. A device according to any one of the preceding claims, wherein the device includes at least one antenna arranged to transmit and/or receive data to/from a remote device.

19. A device according to claim 18, wherein the antenna projects beyond an external surface of the axle.

20. A device according to claim 18 or 19, wherein the antenna protected by a cover,

21. A device according to claim 20, wherein the cover also protects electrical connections between a said at least one force sensor and the electronics.

22. A device according to claim 20 or 21 , the electronics and the antenna provided in a housing and protected by the cover.

23. The device according to claim 21 , wherein the cover protects an electrical connection passing through an opening in the crank arm to the at least one sensor in a cavity in the crank arm.

24. A device according to claim 4, including fastening means to reieasably retain the electronics to one or both of the axle and a said crank arm.

25. A device according to claim 3, including a seal preventing ingress of moisture to the electronics in the axle cavity or hollow.

26. A device according to claim 4, including the axle and a said crank arm provided as an integrated assembly or component.

27. A device according to claim 26, wherein the integrated assembly or component further includes a spider supporting or configured to support a chainwheel or a drive belt drive pulley.

28. A device according to any one of the preceding claims, including at least one rotational sensor at least in part mounted to or forming part of the axle.

29. A device according to claim 28, the at least one rotational sensor operatively connected to the electronics,

30. A device according to claim 28 or 29, the at least one rotational sensor including a portion on the axle and a portion on the bottom bracket or housing around the axie.

31. A device according to claim 28, 29 or 30, wherein the at least one rotational sensor includes one or more of a capacitive, inductive, magneto- resistive and/or optical sensor,

32. A device according to any one of claims 28 to 31 , the at least one rotational sensor includes a passive sensing means.

33. A device according to any one of claims 28 to 32, the at least one rotational sensor including multiple sensor elements or switches.

34. A power meter system for a cycle, the system including a power meter device according to any one of the preceding claims, a pair of crank arms connected by an axle having a cavity to receive the device at least in part, at least one force sensor attached to surface inside a cavity in a said crank arm, a processor to receive and process data signals derived from the at least one force sensor, and a transmitter to transmit processed said data signals.

35. A cyclic cranked system data gathering system, the cyclic cranked system having at least one crank arm operativeiy connected to a crank axie, the data gathering system including at least one data gathering device located at the crank axle, at least one sensor in communication with a said data gathering device, said at least one data gathering device configured to obtain data relating to force applied by the user through the respective crank arm(s) and sensed by the respective at least one sensor

36. The system of claim 35, the at least one crank arm having at least one sensor, each said senor in communication with a said data gathering device.

37. The system of claim 35, the at least one sensor includes at least one force sensor at or on the axle.

38. The system of any one of claims 36 to 37, further including one or more of said sensors associated with a drive or right hand side of the cyclic cranked system.

39. The system of claim 38, wherein the one or more said sensors associated with the drive or right hand side detect total force as applied torque to a drive output of the cyclic cranked system.

40. The system of claim 38 or 39 when dependent upon claim 37, wherein the data gathering device derives a torque contribution of a left hand side or non- drive side of the cyclic cranked system from the sensor(s) at the axle.

41. The system of claim 38, 39 or 40 when dependent upon claim 37, wherein torque contribution from the right hand or drive side is derived by deducting the left hand or non-drive side contribution from total torque being transmitted to the drive output

42. The system of any one of claims 35 to 41 , wherein the data gathering device is provided as a module.

43. The system according to any one of claims 35 to 42, the data gathering device including at least one processor provided at the crank axle to process one or more signals from the sensor(s) relating to force(s) applied by the user through the respective crank arm(s).

44. The system of according to any one of claims 35 to 43, the data gathering device inciuding at least one transmitter connected to an antenna and arranged to transmit processed data to a remote receiver.

45. The system as claimed in claim 44, wherein the antenna is provided at or adjacent an end of the crank axle or on a crank arm.

46. The system of any one of claims 35 to 45, further including a protective cover for electronics housed in or on the data gathering device or axle or crank arm or a combination of one or more thereof.

47. The system of any one of claims 35 to 46, including a power source provided in the crank axle or as part of the data gathering device.

48. The system of claim 47, wherein the power source includes a battery and/or rotational driven electrical generator utilising the rotational motion of the cyclic cranked system to generate power.

49. The system of any one of claims 35 to 48, the data gathering device including connection to the sensors provided on multiple said crank arms.

50. The system of any one of claims 35 to 49, wherein the data gathering device is connected to a sensor provided for a first said crank arm and has provision for connection to an optional second sensor for a second said crank arm.

51. The system of any one of claims 35 to 50, wherein a processor of the data gathering device receives and processes data signals from said first and second sensors, and the transmitter is arranged to transmit the processed data to a remote device.

52. The system of any one of claims 35 to 51 , the data gathering device sealed against ingress of dirt and/or moisture by one or more seals.

53. The system of claim 47, wherein one or more of said seals is/are provided where the crank arm meets the crank axle.

54. The system of any one of claims 35 to 53, providing a power/torque meter for a bicycle.

55. A cycling force detecting system for a hollow crank axle and crank arm assembly, the crank arm supporting a force sensor to, in use, detect forces applied to the crank arm, and a data gathering device arranged and configured to be received into the hollow crank axle.

56. The cycling force detecting system of claim 55, provided as a kit of parts including the data gathering device and at least one said crank arm.

57. The cycling force detecting system of claim 55 or 56, provided as a crank axle including a pre-installed fitted data gathering device and one or more crank arms ready to mount or pre-mounted to the respective end(s) of the crank axle.

58. The cycling force detecting system of any one of claims 55 to 57 wherein the said hollow crank axle supports a force sensor, to in use, detect torque related forces applied to said axle by the non-drive side crank arm of the crank arm assembly.