The present invention relates to a power meter pedal and a method for mounting and aligning such a power meter pedal to a crank arm.

A high variety of bicycle pedal structures is known, but for a common pedal a mounting of a stationary part of the pedal at a certain rotational position relative to a crank arm is no issue. Such a common pedal is mounted at a random rotational position. When comparing such a common pedal with a power meter pedal, a power meter pedal is special in that it requires an alignment of a load sensor with respect to the crank arm. When training with a power meter, a user wants to know how much power is delivered at a certain angle of the crank arm. For that reason, the power meter pedal should be accurately mounted with respect to the crank arm. Mounting structures for common pedals do not feature such a required accurate alignment and are for that reason not suitable to be used for a power meter pedal.

The company SRM markets a power meter pedal branded Exact. This power meter pedal has four strain gauges in a traditional Wheatstone bridge design which are attached to a spindle forming the stationary part of the pedal. A pedal body is rotatable mounted to the spindle. For mounting the Exact power meter pedal, a user holds the spindle at a certain rotational position relative to the crank arm by using a special mounting tool. The mounting tool looks like a standard Allen wrench but has a shaft which is bend in a particular manner. From behind the crank arm, the head of the mounting tool is to be inserted inside a hexagonal socket of a mounting portion of the spindle of the pedal. The rotational position of the spindle is then to be determined by a blue coloured marker aside the socket at an end face of the spindle. The blue coloured marker is visible to the user, such that the user knows how to rotate the spindle to the desired rotational position. After aligning and whilst keeping the spindle in the rotational position, a spanner at a front side of the crank arm is to be used by the user to screw a lock-nut to tighten the spindle to the crank arm. After this, the user may further verify the mounting of the power meter pedal by reading a particular offset by a calibration smartphone app.

Although, in this way the SRM Exact power meter pedal can be mounted at a rotational position which is predetermined by the manufacturer, it is a problem that this way of mounting is not convenient. Another more serious problem is that this mounting appears not stable over time. After a period of time, the setting may creep somewhat and a user has to review and re calibrate the rotational position of the pedal. The general object of the present invention is to at least partially eliminate the above mentioned drawbacks and/or to provide a usable alternative. More specific, it is an object of the invention to provide a mounting assembly of a power meter pedal which allows an accurate and over time stable mounting of the power meter pedal to a crank arm at a certain rotational position.

Any discussion of documents, acts, materials, devices, articles or the like included in the present specification is for the purpose of providing a context for the present invention, and is not to be taken as an admission that any such matters form part of the prior art or were before the priority date of each claim of this application common general knowledge in the field relevant to the present invention.

According to the invention, this object is achieved by a power meter pedal according to claim 1.

According to the invention, a power meter pedal is provided for measuring loads exerted by a user onto the pedal. The power meter pedal comprises a load sensor for measuring the exerted load on the pedal. Herewith, the power meter pedal is configured to provide pedalling force data by converting the measured load.

The power meter pedal is configured to be secured to a bicycle crank arm. The crank arm has a threaded hole at a free end of the crank arm which threaded hole has a crank female thread.

The power meter pedal comprises a mounting assembly which is arranged to accurately and stably mount the power meter pedal to the crank arm.

The mounting assembly includes a pedal spindle with a crank arm mounting portion, a sleeve and a fixing bolt. The mounting assembly serves for mounting the pedal body so as to be rotatable about the pedal spindle to the crank arm. In particular, the pedal body is journalled by bearings about said pedal spindle.

The pedal spindle comprises an elongated pedal spindle body. The pedal spindle body defines an axial axis. The crank arm mounting portion is positioned at a proximal end of the pedal spindle body besides a pedal body supporting portion. The pedal body supporting portion is configured to journal thereon the pedal body. The pedal spindle body includes a mounting member for mounting the mounting assembly to the crank arm. The pedal spindle further comprises a load sensor which is fixed to the pedal spindle body. The load sensor is configured for measurements of loads applied by a user via the pedal body. The load sensor is configured to measure a load in a certain direction. The measurement of the load depends on a directional force exerted on the pedal spindle body. The mounting member is configured to be externally engaged by a tool, like a spanner, to rotate the pedal spindle body relative to the crank arm to get the load sensor in a predetermined orientation. The mounting member allows the user to rotationally position the pedal spindle body at a predetermined rotational position with respect to the crank arm.

The pedal spindle body further comprises a chamber. The chamber has a chamber bottom and a chamber wall. The chamber is positioned at a proximal end face of the pedal spindle body and configured for receiving the sleeve. A female threaded hole is provided at the chamber bottom for receiving the fixing bolt for mounting the sleeve to the pedal spindle.

The sleeve of the mounting assembly comprises a sleeve body. The sleeve body has a male crank arm engaging thread at a proximal end and a sleeve end portion at a distal end of the sleeve body. The male crank engaging thread fits with the crank female thread of the crank arm. The male crank arm engaging thread is configured to mate with said crank female thread of the bicycle crank arm. The sleeve end portion is configured to be inserted into the chamber of the pedal spindle body. The sleeve body has a through hole extending from the proximal end to the distal end of the sleep body. The sleeve body further has an abutment end face. The end face is laying flush or directed towards the proximal end of the sleep body. The end face faces the proximal end for engaging with the fixing bolt.

The fixing bolt of the mounting assembly has a bolt shaft which is provided with a male thread. The bolt shaft has a length and diameter which are configured to extend through the through hole of the sleep body. The male thread at the end of the bolt shaft corresponds with the female threaded hole provided at the chamber bottom of the pedal spindle body. The bolt shaft is configured to be inserted through the sleeve body into the female threaded hole. The fixing bolt further has a bolt head. The bolt head has a cross-section that is larger than the outer diameter of the bolt shaft. The bolt head has a lower face at a side of the bolt shaft. In the mounting assembly the lower face faces the abutment end face of the sleeve body.

The power meter pedal according to the invention is improved in that the pedal spindle body comprises a sensor marker at the mounting portion. The sensor marker is indicative of the orientation of the load sensor held by the pedal spindle body. The power meter pedal according to the invention may provide several benefits.

In assembling the power meter pedal to a crank arm, the sensor marker is positioned at a front side of the crank arm. Due to this front side positioning, the sensor marker is visual during the assembly of the power meter pedal. A user has a clear sight on the sensor marker when mounting the power meter pedal to the crank arm. In contrast with a sensor marker at a rear side of the crank arm as in the prior art of the Exact pedal, according to the invention, the sensor marker is positioned at a front side of the crank arm such that the users view is not obstructed when aligning the power meter pedal with respect to the crank arm.

Another major benefit is provided by the fixing bolt. The pedal spindle body has a proximal end face which is pressed to the crank arm by the fixing bolt. The fixing bolt which is connected to the pedal spindle body provides a relative robust mounting. In comparison with the relatively small width of the lock nut of the SRM Exact power meter pedal, the relatively long bolt shaft of the fixing bolt engages over a long axial distance to the pedal spindle body which allows a great tension force in securing the pedal spindle body to the crank arm. Herewith, the fixing bolt allows a more tightened mounting of the pedal spindle body to the crank arm.

Another benefit is that the mounting assembly according to the invention allows a pedal design which provides a predetermined q-factor. The so-called q-factor relates to a predetermined distance of a centre of the pedal to the crank arm. Beneficially, the mounting assembly according to the invention allows a configuration of the pedal which does not affect a desired q-factor.

In an embodiment of the power meter pedal according to the invention, the mounting member of the pedal spindle body serves as the sensor marker. The sensor marker is formed by the mounting member. The mounting member is oriented in correspondence with the orientation of the load sensor. In manufacturing the pedal spindle body, the mounting member obtains a predefined orientation relative to the load sensor which allows an assembly of the predetermined rotational position of the pedal spindle body to the crank arm. As the orientation of the mounting member corresponds with the orientation of the load sensor, the user can assembled the power meter pedal in a right manner by orienting the mounting member. Herewith, the mounting member provides a clear indication of a correct assembly.

The mounting member has a predefined rotational position regarding a rotational position of the load sensor. Preferably, the rotational position of the mounting member equals the rotational position of the load sensor, such that the mounting member and the load sensor are aligned with each other. The mounting member and the load sensor are preferably positioned in parallel imaginary planes which allows a manufacturing at a high accuracy.

In particular, the mounting member at the mounting portion is oriented in correspondence with a support face of the pedal spindle body which is adapted to support the load sensor. The mounting member may for example comprise one or two mounting holes at an outer circumference to be engaged by a mounting tool in which the positioning of the at least one mounting hole is indicative of the rotational position of the load sensor on the pedal spindle body. By rotating the mounting member relative to the crank arm, the user determines the rotational position of the load sensor. Alternatively, the mounting member may comprise at least one flat outer surface which flat outer surface is rotationally positioned in correspondence with a rotational position of the sensor. The flat outer surface may be rotationally positioned perpendicular to the support face of the load sensor, but preferably, the mounting member has a flat outer surface which is positioned in parallel with the support face of the pedal spindle body which is beneficial in manufacturing the mounting member at high precision relative to the support face. Preferably, the mounting member has opposite positioned flats at a certain spanner width, such that the mounting member is formed to be engaged by a standardised spanner tool. The opposite positioned flats of the mounting member are adapted to be gripped by the spanner tool.

In an embodiment of the power meter pedal according to the invention, the sensor marker is formed by a groove at an outer circumferential surface of the mounting portion. The groove extends in the axial direction. Preferably, the groove is a straight groove. Preferably, the groove extends from the proximal end face in the axial direction of the pedal spindle body.

The groove may be positioned at a flat outer surface of the mounting member. The groove is beneficial in providing a user a visually clear marker of the rotational position of the pedal spindle body. In particular, the groove may be coloured to further increase a visibility to the user.

In an embodiment of the power meter pedal according to the invention, the power meter pedal further comprises a crank marker to be aligned with the sensor marker at the mounting portion of the pedal spindle body. A presence of a crank marker at the crank arm may contribute to obtain a proper orientation of the load sensor with respect to the crank arm. The crank marker and may be embodied by a groove or stamped indicator. A groove-shaped crank marker at the crank arm may be aligned with a groove-shaped sensor marker at the pedal spindle body to obtain a proper alignment of the power meter pedal with respect to the crank arm. Particularly, the crank marker may be embodied as a sticker template. The sticker template may be temporary used by the user to get a crank marker on an existing crank arm when aligning the power meter pedal with the crank arm.

In an embodiment of the power meter pedal according to the invention, the mounting assembly further comprises a set screw for rotationally fixating the pedal spindle body with respect to the sleeve body. Preferably, the sleeve body comprises an outer groove extending in the axial direction for receiving the set screw. Advantageously, the outer groove may increase a robustness of and engagement of the set screw to the sleeve to prevent a rotation of the sleeve body relative to the pedal spindle body.

In an embodiment of the power meter pedal according to the invention, the support face of the pedal spindle body is positioned at a bridge portion which bridge portion forms a load cell. The bridge portion bridges a front and rear portion of the pedal spindle body. The load cell of the pedal spindle body allows the rear portion of the pedal spindle body to deform with respect to the front portion in a predetermined manner. The pedal body is fully supported by the rear portion of the pedal spindle body. The bridge portion is positioned in between the mounting portion and the at least one bearing for journaling the pedal body. An exerted pedal force engages via the bearings of the pedal body to the rear portion of the pedal spindle body at a distal side of the bridge portion.

Preferably, the bridge portion is provided at a top side of the pedal spindle body. In particular, the pedal spindle body has a transversely extending through hole in which a top and bottom sided bridge portion delimits the through hole. The bridge portion of the pedal spindle body preferably has a first bridge reduction and second bridge reduction which second bridge reduction is positioned axially seen behind the first bridge reduction. The first and second bridge reduction each form a weakened region of the bridge portion which allows the bridge portion to act as a link mechanism.

When loaded, the first and second bridge reduction may each provide a pivot point to form a parallelogram link mechanism in which the rear portion of the pedal spindle body may deform by shearing instead of bending with respect to the front portion of the pedal spindle body.

In an embodiment of the power meter pedal according to the invention, the load sensor is a strain sensor. The strain sensor comprises at least one strain gauge for measuring a strain. Preferably, the strain sensor comprises four strain gauges electrically connected in a Wheatstone bridge arrangement. Preferably, all strain gauges are positioned in a common plane. Preferably, the strain sensor is connected to a sensor plate which sensor plate is connected to a support face of the pedal spindle body. In particular, the sensor plate is a printed circuit board. The support face is a flat outer surface of the pedal spindle body configured for an attachment of the sensor plate to the pedal spindle body.

In a further embodiment of the power meter pedal according to the invention, the sensor plate is positioned on top of the support face on top of the bridge portion, wherein a strain gauge is positioned at each of the first and second bridge reduction.

In an embodiment of the power metre according to the invention, the at least one strain gauge is directly deposited, e.g. by a sputter deposition technique, in particular a magnetron sputtering deposition technique, onto the support face of the pedal spindle body. Instead of a sensor plate holding the at least one strain gauge, a directly deposited strain gauge onto the support face of the pedal spindle body may increase accuracy of measurements. Additionally, the direct attachment of the at least one strain gauge onto the pedal spindle body, may reduce differences between several pedal spindle bodies which increases interchangeability.

In an embodiment of the power meter according to the invention, the pedal spindle body further comprises an electronic circuit housing and an electronic circuit accommodated therein. The electronic circuit is electronically connected to the load sensor. The electronic circuit is configured to provide output data representative of pedalling force and/or a pedalling power during a pedal cycle.

In particular, the electronic circuit housing further houses at least one semiconductor component, like a processor, a Bluetooth chip, an Ant+ chip etc. for operating the power meter pedal. Preferably, the electronic circuit comprises the sensor plate and separately a control member for holding control electronics, like the semiconductor components. The control member may be spaced from the sensor plate and connected at another position to the pedal spindle body which beneficially allows a compact configuration of the pedal spindle. Preferably, the attachment of the control member to the pedal spindle body is such that the control member is oriented perpendicular with respect to the sensor plate. Advantageously, in comparison with a parallel arrangement, as in the SRM Exact pedal, due to the perpendicular orientation, the control member is less subjected to pedal forces which might negatively affect the control member.

Advantageously, the electronic circuit housing protects electronics mounted to the pedal spindle body. Preferably, the electronic circuit housing is fixed to the pedal spindle body, such that the electronic circuit housing is no separate item and not releasable from the pedal spindle body. The electronic circuit housing and the pedal spindle body form a one-piece item. The electronic circuit housing may be formed by a heat shrink tube or a cured covering paste, e.g. a cured plastic or resin material to form a one-piece item with the pedal spindle body. The electronic circuit housing preferably surrounds the whole outer diameter of the pedal spindle body to cover vulnerable electronic components at an outer circumference of the pedal spindle body. Preferably, the electronic circuit housing is positioned at a position of the load sensor, wherein the electronic circuit housing covers the load sensor. Preferably, the electronic circuit housing extends from the position of the load sensor towards the mounting portion of the pedal spindle body.

Further, the invention relates to a method for mounting and aligning a power meter pedal for measuring an exerted power via a pedal body to a crank arm. The method comprises the step of providing a power meter pedal according to the invention. The power meter pedal according to the invention comprises a mounting assembly which includes a pedal spindle, a sleeve and a fixing bolt. The pedal spindle has a mounting portion to be externally engaged by a mounting tool, like a spanner, for mounting the power meter pedal to the crank arm.

In a step of the method, the mounting assembly is assembled by inserting a sleep and portion of the sleeve into a chamber of the pedal spindle. In a step, the mounting assembly is further assembled by screwing the fixing bolt through the sleeve into a female threaded hole of the pedal spindle. In a step, fixing bolt is fastened, such that the pedal spindle forms a subassembly with the sleeve in which the pedal spindle is non-rotatable connected to the sleeve. In a step, the mounting assembly is mounted to the crank arm by introducing a male crank arm engaging thread at a proximal end of the sleeve into a crank female thread of the crank arm. The subassembly of the pedal spindle and the sleeve is tightened to the crank arm, such that an end face at the proximal end of the pedal spindle is in abutting engagement with the crank arm. Subsequently, the fixing bolt is somewhat released to allow the pedal spindle to be rotated in a next step of the method. The pedal spindle is rotated relative to the crank arm, such that the sensor marker at a mounting portion of the pedal spindle is aligned with the crank arm. The sensor marker is rotated to obtain a predetermined rotational position of the pedal spindle. Thereafter, the fixing bolt is fastened to secure the pedal spindle at the set rotational position.

In an embodiment of the method according to the invention, a set screw is mounted. The set screw is screwed into the pedal spindle to fixate the subassembly of the pedal spindle and the sleeve. Advantageously, the set screw contributes to a robustness of the mounting assembly. In an embodiment of the method according to the invention, the method further comprises a step of providing a crank marker at the crank arm. Advantageously, the crank marker is helpful to the user in finding a correct alignment of the power meter pedal with the crank arm.

Further, the invention relates to a package of a power meter pedal including instructions for a mounting the power meter pedal, wherein the instructions comprises in the method according to the invention.

In a second aspect, the invention relates to a battery assembly for a power meter pedal, in particular for a power meter pedal according to aspects of the invention as described herein.

The battery assembly is mountable at a distal end of the pedal body. In particular, the battery assembly is also mountable to a distal end of the pedal spindle body. The battery assembly is connectable to a rear portion of the pedal spindle body. The battery assembly comprises a battery holder for holding a battery and a battery cap assembly for pressurising the battery to the battery holder. The battery cap assembly comprises a battery contact member and a rotationally connected battery cap. The battery contact member and the battery cap are connected to each other and together form the battery cap assembly which can be removed by the user for replacing a battery. Preferably, a battery bearing, in particular a ball bearing, is provided in between the battery contact member and the battery cap. In use, the battery bearing allows a relative rotation in between the battery contact member and the battery cap in which the battery cap is stationary relative to the pedal body and the battery holder is stationary relative to the pedal spindle body.

According to the second aspect of the invention, the battery assembly is improved by providing a magnet. The magnet is positioned at a proximal end face of the battery contact member. In an assembly, the method is practically connected to the battery. The magnet is connected to the battery cap, such that when replacing a battery, and removing the battery cap, the battery will remain magnetically connected to the battery cap and removed from the pedal body housing together with the battery cap.

The second aspect of the invention further relates to a method for replacing a battery of a power meter pedal. In a step of the method, the battery assembly according to the second aspect is provided. In a step, the battery lid is removed from the battery assembly, wherein the magnet magnetically couples the battery to the battery lid, such that the battery is taken away from the battery holder at the same time of removing the battery lid. Embodiments according to the second aspect of the invention are defined by the following clauses:

1. Power meter pedal comprising a battery assembly (7) which is mountable to a distal end of a pedal body (90), and in particular connectable to a distal end of a pedal spindle body (10).

2. Power meter pedal according to clause 1, wherein the battery assembly (62) comprises a battery holder (620) for holding a battery (63) and a battery cap assembly (64).

3. Power meter pedal according to clause 2, wherein the battery cap assembly (64) comprises a battery contact member (641), a battery bearing (642), and a battery cap (643).

4. Power meter pedal according to close to our 3, wherein the battery contact member (641) comprises a magnet for holding a battery at a proximal side of the battery contact member by a magnetic connection.

5. Method for replacing a battery of a power meter pedal comprising a step of providing a battery assembly (62) according to any of the preceding clauses and a step of disconnecting a battery from a battery contact member (641) by overcoming a magnetic connection.

In a third aspect, the invention relates to an aero cap for a pedal, in particular a bicycle pedal, more in particular a power meter pedal, more in particular for a power meter pedal according to aspects of the invention as described herein.

The aero cap is configured to be connected to an underside of the pedal, in particular to a pedal frame of the pedal. The aero cap has a top surface which serves as a mounting surface for mounting the aero cap to the underside of the pedal. The mounting surface is adapted to the underside of the pedal. The aero cap has a smooth bottom surface which after mounting to the pedal contributes an increased aerodynamic performance of the pedal. The smooth bottom surface may be arc-shaped. The smooth underside of the aero cap forms a smooth surface which extends along a whole length of the pedal frame. In particular, the aero cap is an injection moulded item. The aero cap may be made of a plastic material.

The aero cap may be a one-piece item for covering an underside of the pedal. In an alternative embodiment of the aero cap according to the third aspect of the invention, the aero cap has an aero cap rear member and aero cap front member which are separate items. The aero cap rear member is mountable behind a pedal spindle of a pedal. The aero cap front member is mountable in front of a pedal spindle of the pedal. Preferably, each aero cap member is mountable by a screw connection to a pedal body of the pedal. The pedal frame may comprise at least one screw hole for connecting the aero cap. Alternatively, the aero cap may be mountable to the pedal body by a snap-connection. In particular, the pedal spindle is exposed in between the aero cap rear and front member. The pedal spindle may form a smooth bridge in between the aero cap rear and front member and may be visible from the outside.

The invention will be explained in more detail with reference to the appended drawings. The drawings show a practical embodiment according to the invention, which may not be interpreted as limiting the scope of the invention, in which:

Fig. 1 shows an exploded view of an assembly of a crank arm and a power meter pedal Fig. 2 shows a frontal view of a power meter pedal according to the invention;

Fig. 3 shows a side view of the power meter pedal of fig. 2;

Fig. 4 shows a back view of the power meter pedal of fig. 2;

Fig. 5 shows a top view of the power meter pedal of fig. 2;

Fig. 6 shows a bottom view of the power meter pedal of fig. 2;

Fig. 7 shows a longitudinal sectional view of the power meter pedal of fig. 5;

Fig. 8 shows a longitudinal sectional view of the power meter pedal of fig. 2;

Fig. 9 shows an exploded view of parts forming the mounting assembly of the power meter pedal of fig. 1; and

Fig. 10 shows a longitudinal sectional view of a pedal spindle body of the power meter pedal of fig. 1.

Identical reference signs are used in the drawings to indicate identical or functionally similar components. The wording front, rear, top, bottom, vertical, horizontal, longitudinal, cross- sectional et cetera are used with reference to gravity and to be understand as relating to an orientation of the power pedal in its normal use to facilitate comprehension of the description and are used in a non-limiting way.

Specific features may also be considered apart from the shown embodiment and may be taken into account in a broader context as a delimiting feature, not only for the shown embodiment but as a common feature for all embodiments falling within the scope of the appended claims. Fig. 1 shows a power meter pedal 9 which is mountable to a crank arm 80. At a proximal end, the crank arm 80 has a mounting portion 83 for mounting the crank arm 80 to a crank shaft.

At a distal end, the crank arm 80 has a threaded hole 81 provided with a crank female thread 82 for securing the power meter pedal 9. Such a power meter pedal 9 is in particular configured for use on a sport bicycle, like a racing, cross, gravel, or all-terrain bike, in which the rider wants to obtain data concerning delivered power during a ride. Power meter pedals are also usable on indoor trainers, like spinning bikes.

The power meter pedal 9 has a pedal body 90 which is rotatable about a pedal spindle 1. Typically, as shown, the pedal body 90 is configured for connecting a cleat of a shoe. The pedal body 90 has a pedal frame 94 including an insertion portion 95 for receiving a front end of the cleat, and a clip portion 96 for clamping a rear end of the cleat.

Fig. 2 shows a frontal view of the power meter pedal 9. The pedal spindle 1 of the power meter pedal defines an axial axis 11. The pedal spindle 1 has an elongated pedal spindle body 10. The pedal spindle body 10 is provided with a load sensor 5. The load sensor 5 is fixed to the pedal spindle body 10. In the assembly of the power meter pedal 9, the load sensor 5 is situated inside the pedal body 90. The load sensor 5 is configured for measurements of loads exerted by the user via the pedal body 90.

According to an aspect of the invention, an improvement is provided in mounting the power meter pedal 9 to the crank arm 80. The power meter pedal 9 has a mounting assembly MA - as further shown in fig. 9- which is formed by the pedal spindle 1 , a sleeve 2 and a fixing bolt 3 for mounting the pedal body 90 to the crank arm 80.

At a proximal end P, the pedal spindle body 10 has a crank arm mounting portion 13 for mounting the power meter pedal 9 to a crank arm 80. The crank arm mounting portion 13 extends outside the pedal body 90. The crank arm mounting portion 13 comprises a mounting member 19 for mounting the mounting assembly MA to the crank arm 80.

Fig. 3-6 show orthogonal views of the power meter pedal 9 in which the mounting member 19 is formed by two opposite positioned flats. The flats 19 are spaced at a certain spanner width for engagement by a spanner tool. The mounting member 19 is to be used in assembling the power meter pedal 9 to the crank arm 80. A person who mounts the power meter pedal 9 to the crank arm 80 may place a spanner tool onto the flats of the crank arm mounting portion 13 to orient the pedal spindle body 10 in a predetermined rotational position regarding the crank arm 80. Here, the mounting member 19 serves as a sensor marker 52. The sensor marker 52 is positioned at the mounting portion 13. The sensor marker 52 is indicative of an orientation of the load sensor 5 which is held by the pedal spindle body. By observing the sensor marker 52, a user understands whether or not the power meter pedal 9 is correctly aligned with the crank arm 80. The sensor marker 52 is situated in front of the crank arm 80 which is beneficial in observing this marker when mounting the power meter pedal 9 to the crank arm 80.

Fig. 7 and 8 show a sectional view of the power meter pedal 9 along the axial axis 11. Fig. 9 shows in an exploded view the components forming the mounting assembly MA in further detail.

As shown, at the proximal end P, the pedal spindle body 10 comprises a chamber 14 for receiving the sleeve 2. The chamber 14 is positioned at an end face of the pedal spindle body 10. The chamber 14 has a chamber bottom 15 and a circumferential chamber wall 16. A female threaded hole 17 is provided at the chamber bottom 15 for receiving the fixing bolt 3.

The sleeve 2 of the mounting assembly MA comprises a sleeve body 20. The sleeve body is open at both ends. The sleeve body 20 has a passageway for putting through the fixing bolt 3. At an outer side, the sleeve body 20 has a male crank arm engaging thread 21. The male crank arm engaging thread 21 is positioned at a proximal end of the sleeve body 20. At a distal end, the sleeve body 20 has a sleeve end portion 22 which is configured to be inserted into the chamber 14 of the pedal spindle body 10. The sleeve body 20 further has an abutment end face 23, in particular an inner abutment end face 23. The inner abutment end face 23 is laying flush or facing towards the proximal end of the sleeve body 20.

The fixing bolt 3 has a bolt shaft 31 which is provided with a male thread 311. The bolt shaft 31 is configured to be inserted through the sleeve body 20 into the female threaded hole 17. The fixing bolt 3 has a bolt head 32. The bolt head 32 has an hexagonal socket at a proximal end face. At the other side, the bolt head 32 includes a lower face 33. The lower face 33 is situated at a side of the bolt shaft 31. In the mounting assembly MA, the lower face 33 is facing the abutment end face 23 of the sleeve body 20.

The mounting assembly MA of the power meter pedal 9 according an aspect of the invention allows a robust mounting of the power meter pedal 9 to the crank arm 80. When mounting the power meter pedal 9, the sleeve end portion 22 of the sleeve is inserted into the chamber 14 of the pedal spindle. The fixing bolt 3 is assembled. The fixing bolt 3 is introduced through the sleeve 2 and mounted to the pedal spindle body 10 by screwing the bolt shaft male thread 311 into the female threaded hole 17 of the pedal spindle body 10. The fixing bolt 3 is fastened to the pedal spindle body 10, such that the mounting assembly MA can be screwed to the female thread 82 of the crank arm 80. A user may put a spanner onto the mounting members 19 of the mounting assembly to screw the power meter pedal to the crank arm.

Subsequently, the power meter pedal 9 should be aligned with the crank arm 80. This means that the power meter pedal 9 is to be oriented in a predetermined rotational position relative to the crank arm. By orienting the pedal spindle 1 of the power meter pedal 9, the load sensor 5 is oriented in a correct rotational position for measuring exerted pedal forces. To align the pedal spindle 1, the fixing bolt 3 is released. The fixing bolt 3 is released about just a minor rotation. A clearance ‘C’ as depicted in Fig. 7 will occur in between the sleeve body 20 and the chamber bottom 15 of the chamber 14 of the pedal spindle body 10. Now, the pedal spindle 1 is loosened and rotatable relative to the crank arm. The pedal spindle 1 is to be aligned by the user by rotating the pedal spindle 1 relative to the crank arm 80. The user rotates the pedal spindle 1 to align the sensor marker 52 at the mounting portion of the pedal spindle with regard to the crank arm 80. Preferably, the crank arm 80 is at least temporarily provided with a crank marker, such that the first sensor marker 52 can be easily aligned with the crank arm by observing the crank marker. After placing the pedal spindle 1 in the correct position, which corresponds with the predetermined rotational position, the fixing bolt 3 is fixed again. By securing the fixing bolt 3, the end face 18 is pressed against the crank arm 80. Herewith, the rotational position of the pedal spindle in alignment with the crank arm is warranted.

Fig. 2 and 7 and 9 further show a set screw 4. The set screw 4 is provided to rotationally fixate the pedal spindle 1 with respect to the sleeve 2 in addition to the fixation by the abutting end face 18 of the pedal spindle body. The set screw 4 is positioned at the crank arm mounting portion 13, in particular at the flat surface forming the mounting member 19. The set screw 4 is mountable from outside into a set screw hole 40 to engage with an outer side of the sleeve body 20. In particular, a distal end of the set screw 4 engages with an outer groove 24 at an outer circumferential surface of the sleeve body 20. The outer groove 24 further contributes to a robust fixation and prevention of a rotation of the sleeve body 20 relative to the pedal spindle body 10.

Fig. 10 shows the pedal spindle 1 in a sectional view about the axial axis 11. The pedal spindle body 10 has a front portion 101 and a rear portion 102. The front and rear portion 101, 102 are delimited by a load cell 54. The load cell 54 is integrally formed with the pedal spindle body 10. The load cell 54 has at least one bridge portion 55 for supporting the load sensor 5. The bridge portion 55 is formed by a traverse through hole through the pedal spindle body 10. Here, the load cell 54 is formed by a top bridge portion 551 and a bottom bridge portion 552. The bridge portion is are configured in mirror symmetry. The bridge portion 55 has a predetermined thickness to allow a conversion of strain stresses to load measurements. The thickness of the bridge portion is locally reduced. Here, the bridge portion 55 has a thickened middle region. The thickened middle region is formed by a first reduction 561 and a second reduction 562.

The bridge portion 55 provides a support face 51 for carrying the load sensor 5. The load sensor 5 is a strain sensor. The strain sensor is configured to measure a tension force. The load sensor 5 comprises at least one strain gauge, in particular four strain gauges electrically connected in a Wheatstone bridge arrangement. Each strain gauge is configured to measure a one directional tension force.

The strain gauges forming the load sensor 5 may be positioned on a sensor plate 50. The strain gauges may be deposited by a sputter deposition technique onto the sensor plate. The sensor plate 50 is attached to the support face 51. Preferably, the sensor plate 50 is connected to the support face 51 by welding. Alternatively, the at least one strain gauge may be directly deposited onto the support face 51 of the pedal spindle body 10. Herewith, all strain gauges for measuring exerted pedal forces are positioned in a common plane. Preferably, the Wheatstone bridge arrangement of strain gauges is aligned with the first and second reduction 561, 562. A left-sided pair of strain gauges of the Wheatstone bridge arrangement is positioned on top of the first reduction 561 and an electronically connected right sided pair of strain gauges is positioned on top of the first reduction 562.

An electronic circuit housing 6 protects electronics mounted to the pedal spindle body. The electronic circuit housing 6 is fixed to the pedal spindle body, such that the electronic circuit housing is no separate item and not releasable from the pedal spindle body. The electronic circuit housing 6 and the pedal spindle body 10 form a one-piece item. The electronic circuit housing 6 may be formed by a heat shrink tube or a cured covering paste, e.g. a cured plastic or resin material to form a one-piece item with the pedal spindle body. The electronic circuit housing may surround the whole outer diameter of the pedal spindle body to cover vulnerable electronic components like the sensor 5 and control member 53 at an outer circumference of the pedal spindle body 10. Here, the electronic circuit housing 6 is positioned at a position of the load sensor, wherein the electronic circuit housing covers the load sensor. Preferably, the electronic circuit housing 6 extends from the position of the load sensor 6 towards the mounting portion 13 of the pedal spindle body 10.

The rear portion 102 is configured to journal the pedal body 90. The rear portion 102 supports the pedal body 90. As shown in figures 7 and 8, bearings 8 are supported by the rear portion 102. The pedal body 9 comprises a pedal body housing 93. The bearings 92, here a first, second and third bearing, are positioned inside a cylindrical space of the pedal body housing 92. In use, exerted pedal forces are transferred via the bearings 92 onto the rear portion 102 of the pedal spindle body 10. As a result, a shear force acts on the load cell 54 situated aside the bearings 92. The load cell 54 supports the load sensor 5. The load sensor 5 is positioned on top of the bridge portion 55 of the load cell 54.

The pedal spindle body 10 is further configured to support a control member 53. The control member 53 comprises electronic components for processing measurements obtained from the load sensor 5. The control member 53 is positioned at a distance from the sensor plate 5. As shown in fig. 8, the control member 53 is positioned away from the sensor support face 51. Here, the control member 53 is a control plate which is oriented in parallel with the sensor plate 50 and attached to a bottom side of the pedal spindle body 10.

Another aspect of the invention as in particular shown in fig. 3 and fig. 6 relates to an aero cap 91 which is mountable to an underside of a pedal, in particular a bicycle pedal. Advantageously, a mounted aero cap 91 increases in aerodynamic performance of the pedal. The aero cap 91 has a smooth outer side which contributes to an aerodynamic performance of a pedal after mounting the aero cap 91 to the pedal body 90. Preferably, the aero cap 91 has an outer contour which corresponds with an outer contour of the underside of the pedal. Herewith, the pedal is smoothened by the aero cap 91 which increases the aerodynamic performance.

Preferably, the aero cap 91 is a moulded item, in particular an injection moulded item, out of a plastic material.

Here, the aero cap 91 comprises an aero cap front member 911 and an aero cap rear member 912. The aero cap is mountable to the underside of the pedal body 90. The aerocap is mountable to the pedal frame 94. The substantially cylindrical-shaped pedal body housing 93 is situated in between the front and rear member 911, 912. The aero cap front member 911 is mountable to the pedal body 90 in front of the cylindrically shaped pedal body housing 93 and the aero cap remember 912 is mountable to the pedal body 90 behind the pedal body housing 93. In particular, the pedal body 90 may be adapted to snap fit the aero cap 91 to the pedal body 90. Alternatively, the aero cap 91 may be mounted by at least one bolt to the pedal body 90.

Another aspect of the invention as shown in fig. 7 and 8 relates to a battery assembly 62 for a power meter pedal 9. The battery assembly 62 is configured for holding a battery 63. The battery assembly is mountable at the distal end of the pedal body 90, in particular to the cylindrical-shaped pedal body housing 93. The battery assembly fits inside the cylindrical inner space of the pedal body housing 93.

The battery assembly 62 comprises a battery holder 620. The battery holder is disc-shaped. One side, a distal side, of the battery holder 620 is arranged for holding the battery 63. Here, the battery holder 620 is recessed for receiving a cell battery. An opposing side, a proximal side, of the battery holder 620 is mountable to the rear portion of the pedal spindle body 10. Here, at the proximal side, the battery holder 620 has a threaded shaft portion for connecting the battery holder 620 to the pedal spindle body 10. At a distal end face, the rear portion 102 of the pedal spindle body 10 has a female thread hole 103 for receiving the threaded shaft of a battery holder 620.

The battery 63 is pressed against the battery holder 620 by a battery cap assembly 64. The battery cap assembly 64 comprises a battery contact member 641 which is rotatably connected to a battery cap 643. The battery contact member 641 is arranged to remain stationary with respect to the pedal spindle body 10, while the battery cap 643 is arranged to remain stationary with respect to the pedal body 90. The battery contact member 641 is relatively movable with respect to the battery cap 643. A battery bearing 642 is positioned in between the battery contact member 641 and the battery cap 643.

The battery contact member 641 further comprises a magnet 644. The magnet 644 provides a magnetic connection between the battery contact member 641 and a battery held by the battery holder 620. This is beneficial in replacing a battery to service the power meter pedal. When removing the battery cap 643, due to the magnetic connection, the battery 63 will be removed together with the battery 643. A user can easily take away an empty battery 63 from the battery cap and replace it by another battery. The battery cap 643 is threaded at its outer circumference and has a grip member, here a hexagonal socket, in a central region to provide a screw connection of the battery ca 643 to the pedal body housing 93. Although the present invention has been described in detail, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the scope of the invention as hereinafter claimed. It is intended that all such changes and modifications be encompassed within the scope of the present disclosure and claims.

Thus, the invention provides a power meter pedal for measuring pedal force data and a method for aligning the power meter pedal relative to a crank arm. A mounting assembly MA of a pedal spindle, a sleeve, and a fixing bolt is provided. The pedal spindle has a mounting member at a mounting portion which further has a sensor marker indicative of an orientation of a load sensor held by a pedal spindle body. A chamber is positioned at a proximal end face for receiving the sleeve. A chamber bottom has a female threaded hole for receiving a bolt shaft. In assembly, an inner abutment end face and a lower face face each other to enable a fasten-release-fasten of the fixing bolt, wherein the sensor marker is aligned during the release of the fixing bolt.

Reference signs

MA mounting assembly C clearance 2 sleeve P proximal 20 sleeve body D distal 21 male crank arm engaging thread F front 50 22 sleeve end portion R rear 23 abutment end face

24 outer groove

9 power meter pedal 3 fixing bolt; cap screw

90 pedal body 55 31 bolt shaft

91 aero cap 310 unthreaded shank

911 aero cap front member 311 bolt shaft male thread

912 aero cap rear member 32 bolt head

92 bearing 33 lower face

921 first bearing 60

922 second bearing 4 set screw

923 third bearing 40 set screw hole

93 pedal body housing

94 pedal frame 5 load sensor; strain sensor

95 insertion portion 65 50 sensor plate

96 clip portion 51 sensor support face

52 sensor marker

8 crank 53 control member

80 crank arm 54 load cell

81 threaded hole 70 55 bridge portion

82 female thread 551 top bridge portion

83 mounting portion 552 bottom bridge portion

561 first reduction

1 pedal spindle 562 second reduction

10 pedal spindle body

101 front portion

102 rear portion 6 electronic circuit housing

103 female thread hole 61 electronic circuit

11 axial axis 62 battery assembly

12 pedal body supporting portion 80 620 battery holder

13 crank arm mounting portion 63 battery

64 battery cap assembly

14 chamber 641 battery contact member

15 chamber bottom 642 battery bearing

16 chamber wall 85 643 battery cap

17 threaded hole for receiving bolt shaft 644 magnet

18 proximal end face

19 mounting member, flattening