crank arm

Abstract

Crank arm (12, 14) comprising: a crank body (22) which has a shaft mounting section (35) and a pedal mounting hole (40); a sensor support member (26) which is attached to the crank body (22), wherein the sensor support member (26) has a shaft support section (28) which is configured to support a pedal shaft (32) as a shaft, wherein the pedal mounting bore (40) of the crank body (22) is arranged concentrically with respect to a threaded hole (62) of the sensor support member (26); and at least one voltage sensor (30) which is arranged on the sensor support member (26); wherein the pedal shaft (32) is arranged as the shaft through the pedal mounting hole (40).

Description

[0001] This invention claims priority from US patent application US 2015 / 0 247 767 A1, filed on February 28, 2014. The entire disclosure of US patent application US 2015 / 0 247 767 A1 is hereby included by reference. Field of invention

[0002] This invention generally relates to a crank arm. In particular, the present invention relates to a crank arm with a sensor support element and a sensor which detects a pedal force. Background information

[0003] Bicycles and exercise bikes are sometimes equipped with various sensors to provide information to the cyclist / user and / or to a controller to manage different aspects of the bicycle or exercise bike, such as shifting gears, suspension stiffness, or motor assistance. One such sensor is a torque or force sensor for detecting the cyclist's pedaling force. Various sensor configurations have been proposed for detecting pedaling force. For example, US Patent No. 7,516,677 B2 (owned by Shimano Inc.) describes a cylindrical, torque-detecting sleeve (force sensor unit) mounted on a crankshaft to detect the pedaling force applied to the crankshaft during pedaling.Another example of a force sensor for detecting a pedal force exerted on a crank arm is found in the Japanese utility model patent number JP 3 047 816 U (see the . Fig. 3 and Fig. 4) disclosed. This utility model patent discloses a torque sensor used to detect relative resistance between a flexible rod and a crank arm. The crank arm and the flexible rod are rotatable around a crankshaft by means of a bearing of a one-way coupling. A free end of the flexible rod contacts a section of the crank arm.

[0004] Not too long ago, strain gauges were used to detect pedal force during pedaling. For example, a force sensor is disclosed in US patent application US 2010 / 0282001A1 (owned by SHIMANO Inc.), which uses a strain gauge to detect a pedaling force applied to a crank axle during pedaling. Another example is disclosed in US patent number US 8006574B2, which uses a strain gauge on a crank arm to detect a cyclist's pedaling force. Typically, the strain gauge must be installed with high precision to obtain accurate measurements. Therefore, the manufacturing costs and / or production time for a crank arm increase when a strain gauge is incorporated to detect a cyclist's / user's pedaling force.

[0005] DE 10 2013 101 960 A1 discloses a bicycle crank arm. The bicycle crank arm has crank units that are provided with a crankshaft mounting section and a pedal mounting section. A sensor carrier element is provided in the cavities of the crank units. A power sensor device is mounted on the sensor carrier element. The sensor carrier element deforms under pressure exerted on the pedal at the pedal mounting section. The power sensor device is equipped with several sensor elements with respect to the longitudinal axis of the crank units.

[0006] In general, the present disclosure relates to a crank arm which is provided with a sensor arrangement which detects a pedaling force or power which is exerted on a crank arm of a bicycle or a bicycle fitness device.

[0007] According to one aspect of the invention, a crank arm is provided which includes a crank body, a sensor support element, and at least one sensor. The crank body has a shaft mounting section and a pedal mounting bore. The sensor support element is attached to the crank body and has a shaft support section configured to support a pedal shaft, wherein the pedal mounting bore of the crank body is arranged concentrically with respect to a threaded hole of the sensor support element. The crank arm includes at least one voltage sensor, which is arranged on the sensor support element. The pedal shaft is arranged through the pedal mounting bore.

[0008] Preferably, the crank arm is designed such that the sensor support element is designed to deform as a result of a pedaling force exerted on the shaft support section.

[0009] Preferably, the crank arm is designed such that the sensor support element is fixedly attached to the crank body, so that the sensor support element is either press-fitted or bonded to the crank body.

[0010] Preferably, the crank arm is designed such that the crank body has a cavity, and the sensor support element is arranged within the cavity of the crank body.

[0011] Preferably, the crank arm is designed such that the crank body has an access bore which communicates with the cavity of the crank body, wherein the access bore is dimensioned in relation to the sensor support member so that the sensor support member is installed in the cavity via the access bore.

[0012] Preferably, the crank arm is designed such that the access bore is arranged on an end face of the crank body.

[0013] Preferably, the crank arm is designed such that the sensor support member has first and second end parts, and wherein the shaft support section is arranged at the first end part of the sensor support member, and wherein the second end part of the sensor support member is fixedly coupled to the crank body, in particular by means of a bolt.

[0014] Preferably, the crank arm is designed such that the voltage sensor includes a plurality of sensor elements which are arranged at different locations on the sensor support member, and in particular the sensor elements are arranged on side surfaces of the sensor support member, and / or are formed from at least one strain gauge and a semiconductor sensor for detecting voltage.

[0015] Preferably, the crank arm is designed such that the crank arm further comprises an electrical amplifier which is arranged on the sensor support member and is operatively connected to the voltage sensor in order to amplify a signal from the voltage sensor, wherein in particular the electrical amplifier is electrically connected to the voltage sensor by means of at least one consisting of an electrical wire and a flexible circuit board.

[0016] Further inventive features, functions, aspects and advantages of the disclosed crank arm will become clear to those skilled in the art in the field of bicycles from the present detailed description, which, in conjunction with the attached drawings, discloses preferred embodiments. BRIEF DESCRIPTIONS OF THE DRAWINGS

[0017] With reference to the attached drawings, which form part of this original revelation: Fig. 1 is a side elevation view of left and right crank arms according to an embodiment according to the invention; Fig. Figure 2 is a side view in cross-section of a left crank arm according to the crank arms as shown in the Fig. 1 shown; Fig. Figure 3 is a side view in cross-section of a right crank arm according to the crank arms as shown in the Fig. 1 shown; Fig. Figure 4 is a front cross-sectional view of the crank arm, which is located in the Fig. 2 is shown, along line 4-4, which shows the sensor support element inside the cavity of the left crank arm; Fig. Figure 5 is a rear cross-sectional view of the crank arm, as shown in the Fig. Figure 2 shows the sensor support element inside the cavity of the left crank arm; Fig. Figure 6 is a partially exploded view of the crank arm, as shown in the Fig. 1 shown; Fig. Figure 7 is a front elevation view of the sensor support element, as shown in the Fig. 4 shown; Fig. Figure 8 is a left side view of the sensor support element, as shown in the Fig. 7 shown; Fig. Figure 9 is a right-side view of the sensor support element, as shown in the Fig. 8 shown; Fig. 10 is an exploded perspective view of the crank arm according to a non-inventive embodiment; Fig. Figure 11 is a side view in cross-section of the crank arm, as shown in the Fig. 10 shown. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0018] Selected embodiments will now be explained with reference to the drawings. It will be clear to those skilled in the art of bicycles from this disclosure that the following descriptions of the embodiments are provided for illustrative purposes only and not for the purpose of limiting the invention as defined by the attached claims and their equivalents.

[0019] Initially referring to the Fig. Figure 1 shows a crankshaft assembly 10 for a bicycle, a bicycle exercise machine, or any other suitable device. A bicycle concept includes a stationary bicycle. The crankshaft assembly 10 has a first (left) crank arm 12 and a second (right) crank arm 14 according to a first embodiment. The free ends of the crank arms 12 and 14 are each provided with a pedal 16. As will become clear, a user exerts a pedaling force on the pedals 16, whereupon this force can be transmitted to the crank arms 12 and 14 to move a chain (not shown) to propel the bicycle forward in a conventional manner or to move a resistance device (such as a wheel) in a bicycle exercise machine. As will be described below, the crankshaft assembly 10 is provided with an input force conversion device 18, which detects a pedaling force in order to transmit information (e.g.,a power which is transferred to the crankshaft assembly 10) which can be transmitted to the cyclist and / or used by means of various electronic components.

[0020] As in the Fig. As shown in Figures 1-3, the crankshaft assembly 10 further includes a crankshaft 20. The first and second crank arms 12 and 14 are fixedly coupled to the crankshaft 20 such that they extend perpendicularly from the crankshaft 20 in opposite directions. In the illustrated embodiment, the first crank arm 12 is attached to a first end 21 of the crankshaft 20 in a detachable and reinstallable manner. The second crank arm 14 is attached to a second end 23 of the crankshaft 20 in a conventional manner (e.g., by press fit, crimping, a locking ring, adhesive, etc.). In the first illustrated embodiment, the second crank arm 14 has a pair of gear rings S1 and S2. The gear rings S1 and S2 are fixed to the second crank arm 14 in a conventional manner (e.g., by ring nuts and ring bolts). As shown in the Fig. 2 and Fig. As can be seen in Figure 3, the longitudinal center of the crankshaft defines a rotation axis A of the crankshaft 10.

[0021] With reference to the Fig. 2 and Fig. In section 3, the first and second crank arms 12 and 14 will now be described in more detail. Essentially, the first and second crank arms 12 and 14 are each provided with a crank body 22, which includes a shaft mounting section 24, a sensor support element 26 attached to the crank body 22 (the sensor support element 26 having a shaft support section 28 configured to support a shaft), and at least one voltage sensor 30 arranged on the sensor support element 26. As will be explained below, the sensor support element 26 and the voltage sensor 30 form the input force transducer apparatus 18, and the sensor support element 26 mounts the voltage sensor 30 to the pedal shaft 32 to measure a torque or power applied to the crank arm.The information from the voltage sensor 30 can then be used to break the force applied by the cyclist and / or to assist in displaying the power or in operating a component of the bicycle or bicycle fitness equipment.

[0022] In particular, the first crank arm 12 includes a crank body 22 which has a cavity 34 that receives the sensor support element 26, while the second crank arm 14 includes a crank body 22 which has a cavity 34 that receives another sensor support element 26, so that each sensor support element 26 is arranged within a respective cavity 34 of the crank body 22. The cavity 34 extends towards the shaft mounting section 24 of the crank body 22. While the crank bodies 22 have different overall configurations, at least one pair of the cavities 34 of the crank bodies 22 are essentially identical in their configuration, so that the voltage sensors 30 are supported within the cavities 34 by means of the sensor support elements 26. For this reason, only the first crank arm 12 will be described in more detail.However, the following description of mounting the voltage sensor 30 inside the cavity 34 using the sensor support element 26 also applies to the second crank arm 14.

[0023] As in the Fig. As shown in Figures 2 to 6, the sensor support element 26 is arranged in the cavity 34 of the crank body 22 and is fixedly attached to the crank body 22. The sensor support element 26 is a rod-shaped element used to position the tension sensor 30 on the crank body 22 in a simple and precise manner such that any tension or deformation occurring in the crank body 22 due to a rotational force is transmitted to the tension sensor 30 via the sensor support element 26. Preferably, the sensor support element 26 is permanently fixed to the crank body 22 at two longitudinally spaced locations on the crank body 22 to ensure that the rotational force is transmitted to the tension sensor 30 via the sensor support element 26.

[0024] As in the Fig. As shown in Figures 2 to 6, the crank body 22 further includes a crankshaft mounting section 35, a pedal mounting section (i.e., the shaft support section 24), and an arm section 36. The cavity 34 is formed in the arm section 36, which is located between the crankshaft mounting section 35 and the pedal mounting section 24. In the first illustrated embodiment, the crankshaft mounting section 35, the pedal mounting section 24, and the arm section 36 are formed in one piece as a single, unified link from a metallic material typically used in the manufacture of crank arms. However, the crank body 22 can be formed from a non-metallic material, such as a fiber-reinforced material (e.g., a carbon fiber material) or a composite material (e.g., a metallic and carbon fiber material).While the crank body 22 is generally a very stiff component, it undergoes a small degree of elastic or compliant bending while a cyclist is pedaling. In other words, the arm section 36 of the crank body 22 is / will be elastically deformed as a result of a pedaling force being applied to the pedal mounting section 24 by means of the pedals 16 while a cyclist is pedaling. The crank body 22 is therefore elastically deformed in response to the application of a pedaling force.

[0025] As in the Fig. As can be seen in Figure 2, the crankshaft mounting section 35 has a spline bore 38. The first crank arm 12 is attached to the crankshaft 20 in a conventional manner. For example, the first crank arm 12 can be modified to have a radial slot extending from the spline bore 38 and to use two clamping bolts that can be screwed into the end section of the crank arm to secure the first crank arm 12 to the crankshaft 20 in a conventional manner. The pedal mounting section 24 has a threaded pedal mounting hole 40 for the fixed attachment of one of the pedals 16. In the case of a first (left) crank arm 12, the thread of the threaded pedal mounting hole 40 is a left-hand thread for attaching the pedals 16. On the other hand, in the case of a second (right) crank arm 14, a right-hand thread is typically used for attaching the pedals 16.The pedal mounting section 24 may include a non-threaded bore through which the pedal shaft may extend, if desired.

[0026] With reference to the inclusion the Fig. In sections 4 to 6, the input force converter apparatus 18 will now be described in more detail. As a bicycle pedals the crank assembly 12, the crank body 22 will undergo a small degree of elastic bending due to the application of the rotational force in the direction of rotation and will be twisted with respect to the longitudinal direction of the crank body 22. In other words, the crank arm will bend slightly based on the pedaling force applied by the cyclist as the cyclist rotates the crank assembly. In this way, the arm section 36 of the crank body 22 will be elastically deformed, causing the pedal mounting section 24 to bend with respect to the crank mounting section 35.

[0027] The sensor support element 26 of the input force transducer apparatus 18 is designed to deform as a result of a rotational force being exerted on the shaft support section 24. In particular, the sensor support element 26 is mounted on the crank body 22 such that the sensor support element 26 will be elastically deformed together with the arm section 36 of the crank body 22 as a result of a pedaling force being exerted on the pedal mounting section 24. In the first illustrated embodiment, the sensor support element 26 of the voltage sensor 30 is supported inside the cavity 34 in a precise and simple manner. In particular, as shown in the Fig. As shown in Figure 6, an end face 44 of the pedal mounting section 24 includes an access bore 42, which communicates with the cavity 34 of the crank body 22 for the insertion of the sensor support element 26 into the cavity 34 of the crank body 22. In this illustrated embodiment, the access bore 42 is arranged on an end face of the crank body and is specifically formed in the pedal mounting section 24. However, the access bore 42 can be formed in an end face of the crankshaft mounting section 35 if desired. In any case, the access bore 42 is dimensioned with respect to the sensor support element 26 such that the sensor support element 26 is / is installed in the cavity 34 via the access bore 42.

[0028] As in the Fig. As shown in Figure 4 to 5, in the first illustrated embodiment, the sensor support member 26 has a first end part 46 and a second end part 48. The voltage sensor 30 is supported at the second end part 48 of the sensor support member 26. In this embodiment, the voltage sensor 30 includes a plurality of (e.g., 4) sensor elements 50, 52, 54, and 56, which are arranged at different locations on the sensor support member 26. For example, the sensor elements 50, 52, 54, and 56 can be arranged on side surfaces 58 and 60 of the sensor support member 26 and are preferably formed from at least one strain gauge and a semiconductor sensor for detecting a voltage or deformation.

[0029] The first end part, corresponding to the shaft support section 24, is in contact with the crank body 22 at a first location, which corresponds to a section of the access bore 42 on the cavity 34. The sensor support element 26 is fixed to the crank body 22 such that it is either press-fitted or bonded to the crank body 22. Additionally, the shaft support section 28 is designed to support a pedal shaft 32 and is configured to be coupled to the pedal shaft 32. The shaft support section 28 of the sensor support element 26 closes a threaded hole 62, which can be located on the first end part 46 of the sensor support element 26.The pedal mounting bore 40 of the crank body 22 is arranged concentrically with respect to the threaded hole 62 of the sensor support member 26, and the pedal shaft 32 is designed to be arranged through the pedal mounting bore 40 and to engage with the pedal mounting bore 40.

[0030] The second end part 48 of the sensor support element 26 is in contact with the crank body 22 at a second location and is fixedly coupled to the crank body 22. As shown in the Fig. As shown in Figure 6, the second end part 48 of the sensor support member 26 is fixed to the crank body 22 by means of a bolt 64 or a plurality of bolts 64. This means that the bolts 64 extend through openings 66 in the outer surface 68 of the crank arm and engage the threaded openings 70 in the sensor support member 26. However, the second end part 48 can be fixed to the crank body 22 in any desired manner. The openings 66 are located on the inner surface of the crank body 22 when the crank assembly 10 is attached to a bicycle frame. Furthermore, in this embodiment, the openings 66 are arranged on the side of the pedal mounting section along a line drawn through the center in the longitudinal direction of the crank arm 12.

[0031] In this arrangement, the tension sensor 30 is supported in the cavity 34 in a central region of the crank arm, and the first and second end parts 46 and 48 are located at different sections within the cavity 34. Furthermore, in this embodiment, the tension sensor 30 is positioned on the side facing the pedal mounting section along a line drawn through the center of the longitudinal direction of the crank arm 12. Preferably, in this embodiment, the first end part 46 comes into firm contact with the inner surface of the cavity 34 at the pedal mounting section 24 and is fixed within the cavity 34 by using the threaded connection with the pedal 16 and / or an adhesive connector between them, to ensure that the pedaling force is transferred from the crank body 22 to the tension sensor 30 in a suitable manner via the sensor support element 26.

[0032] The second end part 48 is firmly in contact with the inner surface of the cavity 34 to ensure the transfer of pedaling force from the crank body 22 to the end part 48. The second end part 48 preferably includes a rectangular section that accommodates an electrical wire or wires and / or a flexible conductor circuit (a flexible printed circuit board) 76. Preferably, the second end part 48 is firmly in contact with the inner surface of the cavity 34, as mentioned above, and is fixed within the cavity 34 by means of bolts 64 and / or an adhesive connector and / or a press fit between them to ensure that the pedaling force is appropriately transmitted from the crank body 22 to the voltage sensor 30 via the sensor support element 26.

[0033] In other words, the second end part 48 has a maximum width that is equal to or less than the maximum width of the first end part 46 of the sensor support member 26, in order to facilitate the installation of the sensor support member 26 into the crank body 22. In this embodiment, the second end part 48 tapers, as shown in the Fig. Figures 7 to 9 show the first end part 46 extending inwards, i.e., internally, so that it has a rectangular cross-sectional area which is smaller than the rectangular cross-sectional area of ​​the first end part 46. Additionally, the first end part 46 has a maximum width which is equal to or less than the maximum width of the access bore 42, so that the first end part 46 is held securely in the cavity 34. In this way, the second end part 48 can easily pass through the access bore 42 during the insertion of the sensor support element 26 into the crank body 22 through the access bore 42.

[0034] In this embodiment, the four sensor elements 50, 52, 54 and 56 of the voltage sensor 30 are arranged at different angular locations with respect to a longitudinal axis of the crank body 22. Preferably, as shown in the Fig. As shown in Figures 7 to 9, the second end part 48 of the sensor support member 26 has a rectangular cross-section with respect to the longitudinal axis of the crank body 22. The second end part 48 of the sensor support member 26 therefore defines two side surfaces 58 and 60, each with two sensor elements 50, 52, 54, and 56, which are arranged on each of the side surfaces 58 and 60 of the sensor support member 26. The sensor elements 50, 52, 54, and 56 are arranged on opposite side surfaces 58 and 60 of the second end part 48, which are perpendicular to the axis of rotation A of the first crank arm 12. The detection directions of the four sensor elements 50, 52, 54, and 56 extend in the longitudinal direction of the first crank arm 12.

[0035] While the voltage sensor 30 includes four sensor elements 50, 52, 54, and 56, the voltage sensor 30 can be constructed with only two of the sensor elements (e.g., 50 and 54), such that one sensor element is arranged on each of the two side surfaces 58 and 60 of the second end part 48 of the sensor support member 26. The sensor elements 50, 52, 54, and 56 are formed from at least one voltage sensor 30 and a semiconductor sensor for detecting tension or deformation in the crank arm.

[0036] As in the Fig. As shown in Figures 7 to 9, an electrical amplifier 74 is arranged at the second end part 48 of the sensor support element 26 and is operatively connected to the voltage sensor 30 to amplify a signal from the voltage sensor 30. In this embodiment, the electrical amplifier 74 is electrically connected to the voltage sensor 30 via at least one electrical wire 76. The amplifier 74 enables the voltage sensor 30 to achieve high gain while simultaneously achieving low power consumption, low thermal drift, and low noise. For an example of a voltage amplifier, see WO 2009 / 006673, the entire disclosure of which is hereby incorporated by reference.

[0037] As in the Fig. 2 and Fig. As shown in Figure 3, in the first embodiment, each of the first and second crank arms 12 and 14 further includes a communication unit 78. It will be clear from this disclosure that the communication units 78 can be combined into a single communication unit, which is mounted on either one of the crank arms 12 and 14 or on the crankshaft 20, as required and / or desired. The communication units 78 each have an electrical connector 80. The crankshaft assembly 10 further includes a battery unit 82, which is mounted inside the crankshaft 20. The battery unit 82 has a pair of electrical connectors 80, which connect to the electrical connectors 80 of the communication units 78.

[0038] The communication units 78 are electrically connected to the voltage sensors 30 in a conventional manner using electrical conductors 84, which can be, for example, electrical wires or flexible electrical circuit boards. The battery unit 82 supplies electrical current to the communication units 78. The voltage sensors 30 of the first and second crank arms 14 and 16 are operatively connected to the communication units 78 via the electrical conductors 84 in order to receive signals from the voltage sensors 30. Based on signals from the voltage sensors 30, the communication units 78 output information to various bicycle components as required and / or desired. While the communication units 78 are mounted on the crank arms, they can also be located elsewhere.For example, if the crank body 22 is made of a metallic material, the communication units 78 are preferably arranged outside or on the crank body 22. While the battery unit 82 is arranged in the hollow interior of the crankshaft 20, in the illustrated embodiment the battery unit 82 can also be located elsewhere.

[0039] Preferably, each of the communication units 78 includes a microprocessor and a transmitter, enabling the communication unit 78 to wirelessly transmit information to one or more electronic bicycle components, such as the bicycle computer, the electronic front derailleur, and the electronic rear derailleur. Alternatively, the communication units 78 can be operatively connected to one or more of the bicycle computer, the electronic front derailleur, and the electronic rear derailleur by means of one or more electrical lines.

[0040] A second embodiment of the non-inventive invention, which shows a first crank arm 12', is described in the Fig. 10 and Fig. Figure 11 shows that in this embodiment, the input force converter apparatus 18' includes a sensor support member 26' with a first shaft support section 68 and a second shaft support section 88. In this embodiment, the first shaft support section 86 of the sensor support member 26' is configured to support a crankshaft 20 as the shaft. In addition, the shaft support section 88 of the sensor support member 26' is configured to support the pedal shaft 32. Similarly, the second shaft support section 88 is configured to support the pedal shaft as the shaft, and the first shaft support section is further configured to support the crankshaft 20 as another shaft, as shown in the Fig. Figure 11 shows that the sensor support member 26' can, if desired, be attached to the crankshaft at one end and to the inside of the crank arm at another end (such as a second end) using bolt 64. This means that the sensor support member 26' does not necessarily need to support both the crankshaft and the pedal shaft.

[0041] As in the Fig. 10 and Fig. As shown in Figure 11, the crankshaft mounting section 35 of the crank body 22 has a spline bore 38. In this non-inventive embodiment, the first shaft support section 86 also has a spline bore 90, which essentially corresponds to the spline bore 38 of the crankshaft mounting section. Additionally, the first crank arm 12' can be attached to the crankshaft 20 using a locking ring or retaining ring. However, the first crank arm 12' can also be attached to the crankshaft 20 in any conventional manner. The pedal mounting section 24 has a threaded pedal mounting bore 40 for the fixed attachment of one of the pedals 16. In this non-inventive embodiment, the sensor support member 26' is therefore fixed in at least two positions inside the cavity 34 of the crank arm by means of the crankshaft 20 and the pedal shaft 32.In addition, if desired, the sensor support member 26' can be attached to the crank arm 12' using bolt 64, as described above.

[0042] In this embodiment, the first crank arm 12' includes an access bore 42' at the end of the crank arm adjacent to the crankshaft. As with the access bore 42 described above, this access bore 42' allows the sensor support member 26' to be inserted into the cavity 34 in the crank arm. Although the access bore 42' is located in the Fig. 10 and Fig. 11 is shown as being arranged at the end which is adjacent to the crankshaft, the access bore 42' can be located at the end which is adjacent to the pedal shaft 32, or the access bore 42 can be located at both ends, if desired.

[0043] As in the Fig.As shown in Figure 10, the sensor support member 26' has rounded ends in a similar manner to the crank arm. Furthermore, the electrical wires connecting the flexible circuit board or tension plate to the voltage sensor 30 extend through the spline bore 90 in the sensor support member 26' and through the openings 92 on the side 60' of the sensor support member 26'. This structure allows the flexible circuit board or tension plate with the amplifier to extend through the spline bore 90 and into the crankshaft 20.

[0044] The sensor support element 26' is therefore, as has become clear, fixed to the crank arm in two positions. The sensor support element 26' is fixed in the first position by means of the crankshaft 20, which engages with the spline bore 90, and fixed in the second position by means of the pedal shaft 32, which engages with the threaded hole 62, and / or by means of the bolts 64, which engage with the threaded openings 70. In addition, the sensor support element 26' can be fixed to the crank arm in any desired manner.

[0045] For the purposes of understanding the scope of the present invention, the term "comprise" and its derivatives, as used herein, are intended as open-ended terms that specify the presence of the aforementioned features, elements, components, groups, integers, and / or steps, but do not exclude the presence of other unmentioned features, elements, components, groups, integers, and / or steps. The foregoing also applies to words with a similar meaning, such as the terms "include," "exist," and their derivatives. Similarly, the terms "part," "section," "link," or "element," when used in the singular, may have the dual meaning of a single part or a plurality of parts, unless otherwise specified.

[0046] As used herein, the following directional terms "front," "rear," "side," "horizontal," and "vertical," as well as any other similar directional terms, refer to the orientation of a bicycle in an upright riding position, equipped with the chain tensioning device. Similarly, the directional terms used to describe the chain tensioning device should be understood in relation to a bicycle in an upright riding position on a horizontal surface, equipped with the crank arm. The terms "left" and "right" are used to indicate the right side when referring to the right side from the rear of the bicycle, and to indicate the left side when referring to the left side from the rear of the bicycle.

[0047] It will also be understood that, although the terms "first" and "second" can be used here to describe different components, these components are not intended to be limited by these terms. These terms are only used to distinguish one component from another. Thus, for example, a first component, as described above, could also be called a second component and vice versa, without deviating from the teaching of the present invention.The term "fastened" or "fastening," as used here, encompasses configurations in which one element is directly secured to another by directly attaching the element to the other element; configurations in which the element is indirectly secured to the other element by attaching the element to one or more intermediate elements, which in turn are attached to the other element; and configurations in which one element is integral with another element, i.e., one element is essentially a part of the other element. This definition also applies to words of a similar meaning, such as "connected," "coupled," "mounted," "bonded," "fixed," and their derivatives.Finally, terms of a certain magnitude, such as "essentially", as used here, mean a degree of deviation from the modified term such that the end result is not substantially changed.

[0048] While only selected embodiments have been chosen to illustrate the invention, it will be clear to those skilled in the art of bicycles from this disclosure that various changes and modifications can be made without deviating from the scope of the invention as defined by the appended claims. For example, the size, shape, location, or orientation of various components can be changed as needed and / or desired, provided that the changes do not substantially affect their intended functions. Components shown to be directly connected or in contact with one another may have intermediate structures between them, provided that the changes do not substantially affect their intended functions. The functions of one element can be performed by two, and vice versa.The structures and functions of an element can be adopted in another embodiment. It is not necessary for all advantages to be present in a particular embodiment at the same time. Each feature that is unique with respect to the prior art, either on its own or in combination with other features, shall also be considered a separate description of a further invention by the applicant, including the structural and / or functional concepts embodied by such features. The preceding descriptions of the embodiment according to the present invention are therefore provided for illustrative purposes only and not for the purpose of limiting the invention as defined by the attached claims and their equivalents.

Claims

[1] Crank arm (12, 14) comprising: a crank body (22) which has a shaft mounting section (35) and a pedal mounting hole (40); a sensor support member (26) which is attached to the crank body (22), wherein the sensor support member (26) has a shaft support section (28) which is configured to support a pedal shaft (32) as a shaft, wherein the pedal mounting bore (40) of the crank body (22) is arranged concentrically with respect to a threaded hole (62) of the sensor support member (26); and at least one voltage sensor (30) which is arranged on the sensor support member (26); wherein the pedal shaft (32) is arranged as the shaft through the pedal mounting hole (40). [2] Crank arm (12, 14) according to claim 1, wherein the sensor support member (26) is designed to deform as a result of a pedaling force exerted on the shaft support section (28). [3] Crank arm (12, 14) according to one of claims 1 or 2, wherein the sensor support member (26) is fixedly attached to the crank body (22) such that the sensor support member (26) is either press-fitted or bonded to the crank body (22). [4] Crank arm (12, 14) according to one of claims 1 to 3, wherein the crank body (22) has a cavity (34) and the sensor support member (26) is arranged within the cavity (34) of the crank body (22). [5] Crank arm (12, 14) according to claim 4, wherein the crank body (22) has an access bore (42) which communicates with the cavity (34) of the crank body (22), wherein the access bore (42) is dimensioned with respect to the sensor support member (26) such that the sensor support member (26) is installed in the cavity (34) via the access bore (42). [6] Crank arm (12, 14) according to claim 5, wherein the access bore (42) is arranged on an end face of the crank body (22). [7] Crank arm (12, 14) according to one of claims 1 to 6, wherein the sensor support member (26) has first (46) and second end parts (48), and wherein the shaft support section (28) is arranged on the first end part (46) of the sensor support member (26), and wherein the second end part (48) of the sensor support member (26) is fixedly coupled to the crank body (22), in particular by means of a bolt (64). [8] Crank arm (12, 14) according to one of claims 1 to 7, wherein the voltage sensor (30) includes a plurality of sensor elements (50; 52; 54; 56) which are arranged at different locations on the sensor support member (26), and in particular the sensor elements (50; 52; 54; 56) are arranged on side surfaces of the sensor support member (26), and / or are formed from at least one strain gauge and a semiconductor sensor for detecting voltage. [9] Crank arm (12, 14) according to one of claims 1 to 8, further comprising an electrical amplifier (74) which is arranged on the sensor support member (26) and is operatively connected to the voltage sensor (30) to amplify a signal from the voltage sensor (30), wherein in particular the electrical amplifier (74) is electrically connected to the voltage sensor (30) by means of at least one consisting of an electrical wire (76) and a flexible circuit board.

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