Crank arm for crank assembly of human powered vehicle

Abstract

This invention discloses a crank arm comprising an arm body, a shaft fastener, and a biasing element. The arm body includes a crankshaft receiving opening and a shaft fastener receiving opening. The shaft fastener receiving opening has a second opening axis. The shaft fastener receiving opening communicates with the crankshaft receiving opening portion via a connecting opening. The shaft fastener includes a fastener body having a latch portion. The latch portion is configured to engage with a latch end of the crankshaft in an mounted state where the crank arm is mounted to the crankshaft. The biasing element is configured to bias the shaft fastener in a biasing direction parallel to the second opening axis.

Description

Technical Field

[0001] This invention relates to a crank arm for a crank assembly in a human-powered vehicle. Prior Technology

[0002] A human-powered vehicle includes a crank assembly. The crank assembly includes a crank arm and a crankshaft. The crank arm is fastened to the crankshaft. For example, a crank arm having a fastening opening and a slit is fastened to the crankshaft using a crank arm bolt (see, for example, EP Publication No. 1426282A2). Alternatively, the crank arm can be fastened to the crank arm using a bolt and a plurality of components (see, for example, U.S. Publication No. 2005 / 0040699). In the fastening structure of U.S. Publication No. 2005 / 0040699, the fastening force between the crank 10 and the shaft 30 may be insufficient because the tubular member 21 does not have a groove portion to engage with the grooved end 31 of the shaft 30. It preferably makes assembling the crank assembly easier, improves the stiffness of the crank arm, and / or improves one of the appearances of the crank arm. Summary of the Invention

[0003] According to a first aspect of the present invention, a crank arm for a crank assembly of a human-powered vehicle includes an arm body, a shaft fastener, and a biasing element. The arm body includes a crankshaft receiving opening and a shaft fastener receiving opening. The crankshaft receiving opening has a first opening axis and a grooved periphery configured to receive and engage a grooved end of a crankshaft. The shaft fastener receiving opening has a second opening axis not parallel to the first opening axis. The shaft fastener receiving opening communicates with a portion of the crankshaft receiving opening via a connecting opening. The shaft fastener is configured to be inserted into the shaft fastener receiving opening and includes a fastener body having a grooved portion. The grooved portion is configured to engage with the grooved end of the crankshaft in an mounted state where the crank arm is mounted to the crankshaft. The biasing element is configured to bias the shaft fastener in a biasing direction parallel to the second opening axis. The groove portion of the fastener body is configured to overlap the connection opening in one of the insertion states in which the shaft fastener is inserted into the shaft fastener receiving opening to engage with the groove end of the crankshaft.

[0004] Regarding the crank arm according to the first embodiment, the biasing element is configured to bias the shaft fastener in a state in which the groove portion of the fastener body engages with the groove end of the crankshaft. This makes fastening the crank arm to the crankshaft easier and / or eliminates a slit included in a comparative embodiment of the arm body. Therefore, the assembly of the crank assembly can be improved, the stiffness of the crank arm can be improved due to the groove engagement between the fastener body of the shaft fastener and the groove end of the crankshaft, and / or the appearance of the crank arm can be improved.

[0005] According to a second embodiment of the invention, the crank arm of the first embodiment is configured such that, when viewed from a projection direction that is radially defined relative to the first opening axis and perpendicular to the second opening axis, the first opening axis of the crank shaft receiving opening is perpendicular to the second opening axis of the shaft fastener receiving opening.

[0006] Regarding the crank arm of the second configuration, the positional relationship between the first open axis and the second open axis allows for efficient transmission of the biasing force of the biasing element to the engagement member between the groove portion of the shaft fastener and the groove end of the crank arm. This reliably makes it easier to fasten the crank arm to the crankshaft.

[0007] According to a third embodiment of the invention, the crank arm according to the first or second embodiment further includes a shaft bolt. The shaft bolt includes a bolt body and a radial protrusion. The bolt body has external threads configured to engage with the internal threads of the crank shaft in the installed state. The radial protrusion extends radially outward from the bolt body relative to the first opening axis and is configured to abut against the arm body in one of the axial directions relative to the first opening axis in the installed state.

[0008] Regarding the crank arm in the third configuration, the shaft bolt effectively restricts the movement of the crank arm relative to the crank shaft in the axial direction.

[0009] According to a fourth embodiment of the present invention, the crank arm of any of the first to third embodiments is configured such that the shaft fastener further includes a positioning structure configured to position the fastener body in the inserted state.

[0010] Regarding the crank arm of the fourth state, the positioning structure can position the fastener body in an engagement position in which the groove portion of the shaft fastener can engage with the groove end of the crank shaft.

[0011] According to a fifth embodiment of the present invention, the crank arm of the fourth embodiment is configured such that the positioning structure includes a movable member, a biasing member, and a receiving chamber. The biasing member is configured to bias the movable member in a direction away from the fastener body. The receiving chamber is formed to the fastener body and configured to receive the movable member and the biasing member.

[0012] Regarding the crank arm of the fifth configuration, the positioning structure can reliably position the fastener body in the engagement position.

[0013] According to a sixth aspect of the present invention, the crank arm of the fifth aspect is configured such that the positioning structure further includes a receiving groove formed to the arm body and configured to receive the movable member.

[0014] Regarding the crank arm of the sixth state, this positioning structure can more reliably position the fastener body in the engagement position.

[0015] According to a seventh embodiment of the present invention, the crank arm of the fourth embodiment is configured such that the positioning structure includes an elastic ring and an annular groove formed to the fastener body and configured to receive the elastic ring.

[0016] Regarding the crank arm of the seventh configuration, the positioning structure can reliably position the fastener body in the engagement position using a smaller number of its components.

[0017] According to an eighth state of the present invention, the crank arm of any of the first to seventh states is configured such that the bias direction is opposite to one of the rotational drive directions of the crank arm.

[0018] Regarding the crank arm of the eighth state, the crank arm can be reliably fastened to the crank shaft.

[0019] According to a ninth embodiment of the present invention, the crank arm of any one of the first to eighth embodiments is configured such that the fastener body of the shaft fastener is formed as an integral single-piece component.

[0020] Regarding the crank arm according to the ninth configuration, the number of components of the crank arm can be reduced. Therefore, the weight of the crank arm can be reduced and / or the manufacturing cost of the crank arm can be lowered.

[0021] According to a tenth embodiment of the present invention, the crank arm of the ninth embodiment is configured such that the biasing element can contact one end of the fastener body of the shaft fastener to bias the fastener body of the shaft fastener in the biasing direction.

[0022] Regarding the crank arm according to the tenth configuration, the number of components of the crank arm can be reliably reduced. Therefore, the weight of the crank arm and / or the manufacturing cost of the crank arm can be reduced.

[0023] According to an eleventh embodiment of the invention, the crank arm of any of the first to tenth embodiments is configured such that the biasing element has external threads. The arm body has internal threads formed in the shaft fastener receiving opening and configured to engage with the external threads of the biasing element.

[0024] Regarding the crank arm of the eleventh configuration, the crank arm can be reliably fastened to the crankshaft. Simple Explanation of the Diagram

[0025] A more complete and better understanding of the invention and its many accompanying advantages will be readily obtained by referring to the following detailed description in conjunction with the accompanying drawings.

[0026] Figure 1 is a perspective view of a crank assembly including a crank arm according to a first embodiment.

[0027] Figure 2 is an exploded perspective view of one of the crank assemblies shown in Figure 1.

[0028] Figure 3 is a cross-sectional view of the crank assembly taken along line III-III of Figure 4.

[0029] Figure 4 is a cross-sectional view of the crank assembly taken along line IV-IV in Figure 3.

[0030] Figure 5 is a cross-sectional view of the crank assembly taken along line VV in Figure 9.

[0031] Figure 6 is a cross-sectional view of the crank assembly taken along line VI-VI of Figure 9.

[0032] Figure 7 is a cross-sectional view of the crank assembly taken along line VII-VII of Figure 8.

[0033] Figure 8 is a perspective view of one of the crank arms of the crank assembly shown in Figure 1.

[0034] Figure 9 is a cross-sectional view of the crank assembly taken along line IX-IX in Figure 5.

[0035] Figure 10 is a cross-sectional view of the crank assembly taken along line XX in Figure 5.

[0036] Figure 11 is a cross-sectional view of the crank assembly taken along line XI-XI in Figure 5.

[0037] Figure 12 is an enlarged cross-sectional view of one of the crank assemblies shown in Figure 6.

[0038] Figure 13 is an exploded perspective view of a crank assembly including a crank arm according to a second embodiment.

[0039] Figure 14 is a cross-sectional view of the crank assembly taken along line XIV-XIV in Figure 15.

[0040] Figure 15 is a cross-sectional view of the crank assembly taken along line XV-XV in Figure 14.

[0041] Figure 16 is a cross-sectional view of a crank assembly including a crank arm according to a third embodiment. Implementation

[0042] Several embodiments will now be described with reference to the accompanying drawings, wherein the same element symbols denote corresponding or identical elements in all the various drawings. First Embodiment

[0043] As shown in Figure 1, a crank assembly 10 for a human-powered vehicle 2 is rotatable relative to a vehicle body 2A about a rotation axis A1. The crank assembly 10 is configured to rotate relative to the vehicle body 2A about the rotation axis A1 in a rotational drive direction D1 during pedaling. The crank assembly 10 includes a crank arm 12 and a crank shaft 14. The crank shaft 14 extends along the rotation axis A1. The crank arm 12 is fastened to the crank shaft 14. The crank arm 12 is fastened to one end of the crank shaft 14. The crank assembly 10 includes an additional crank arm (not shown) fastened to the other end of the crank shaft 14. In a first embodiment, the crank arm 12 is a left crank arm. However, the configuration of the crank arm 12 may be applied to a right crank arm as needed and / or desired.

[0044] In this application, a human-powered vehicle is a vehicle propelled by at least one human power source, including a user (i.e., a rider) riding the vehicle. Human-powered vehicles include various types of bicycles, such as a mountain bike, a road bike, a city bike, a freight bike, a hand-cranked bicycle, and a recumbent bicycle. Furthermore, human-powered vehicles include electric bicycles (E-bikes). Electric bicycles include electric-assisted bicycles configured to use an electric motor to assist in vehicle propulsion. However, the total number of wheels in a human-powered vehicle is not limited to two. For example, a human-powered vehicle includes vehicles with one wheel or three or more wheels. Specifically, human-powered vehicles do not include vehicles that use only an internal combustion engine as their power source. Generally, a light road vehicle (which includes vehicles that do not require a public road driver's license) is considered a human-powered vehicle.

[0045] In this application, the following directional terms "forward," "rearward," "forward," "backward," "left," "right," "lateral," "upward," and "downward," as well as any other similar directional terms, refer to the direction determined based on a user (e.g., a rider) in a standard user position (e.g., on a saddle or seat) facing a handlebar or steering mechanism in the human-powered vehicle 2. Therefore, such terms used to describe the crank assembly 10, crank arm 12, or other components should be interpreted relative to the human-powered vehicle 2 equipped with the crank assembly 10, crank arm 12, or other components, as used in an upright riding position on a horizontal plane.

[0046] As shown in Figure 1, the crank arm 12 of the crank assembly 10 for the human-powered vehicle 2 includes an arm body 16. The arm body 16 includes a first longitudinal end 16A and a second longitudinal end 16B. The arm body 16 extends between the first longitudinal end 16A and the second longitudinal end 16B. The first longitudinal end 16A is fastened to a crankshaft 14. The first longitudinal end 16A of the arm body 16 is fastened to one end of the crankshaft 14. The arm body 16 includes a pedal rotatably coupled to a pedal attachment hole 16H. The second longitudinal end 16B includes the pedal attachment hole 16H.

[0047] As shown in Figure 2, the arm body 16 includes a crankshaft receiving opening 22. The crankshaft 14 includes a latch end 24. The crankshaft receiving opening 22 has a first opening axis A2 and a latch inner periphery 26. The latch inner periphery 26 is configured to receive and engage with the latch end 24 of the crankshaft 14. The latch inner periphery 26 at least partially defines the crankshaft receiving opening 22. In a state in which the crank assembly 10 is rotatably mounted to the vehicle body 2A of the human-powered vehicle 2, the first opening axis A2 coincides with the rotation axis A1 of the crank assembly 10. The first longitudinal end 16A of the arm body 16 does not have a slit extending radially outward from the crankshaft receiving opening 22 to an outer surface of the first longitudinal end 16A.

[0048] The inner periphery 26 of the bolt groove includes a plurality of internal teeth 26A arranged circumferentially around the first opening axis A2. The plurality of internal teeth 26A at least partially define the crankshaft receiving opening 22. The bolt groove end 24 includes a plurality of external teeth 24A arranged circumferentially around the first opening axis A2.

[0049] As shown in Figure 3, the plurality of internal teeth 26A on the periphery 26 of the bolt groove are configured to mesh with the plurality of external teeth 24A on the bolt groove end 24 of the crankshaft 14. In the first embodiment, the total number of one of the plurality of internal teeth 26A on the periphery 26 of the bolt groove is equal to the total number of one of the plurality of external teeth 24A on the bolt groove end 24. The total number of the plurality of internal teeth 26A on the periphery 26 of the bolt groove is 38. The total number of the plurality of external teeth 24A on the bolt groove end 24 is 38.

[0050] However, the total number of the plurality of internal teeth 26A within the periphery 26 of the pin groove may differ from the total number of the plurality of external teeth 24A at the pin groove end 24, depending on need and / or expectation. The total number of the plurality of internal teeth 26A within the periphery 26 of the pin groove may be less than or greater than the total number of the plurality of external teeth 24A at the pin groove end 24, depending on need and / or expectation. The total number of the plurality of internal teeth 26A within the periphery 26 of the pin groove is not limited to the above-mentioned number. The total number of the plurality of external teeth 24A at the pin groove end 24 is not limited to the above-mentioned number.

[0051] As shown in Figure 2, the crank arm 12 further includes a shaft bolt 28. The shaft bolt 28 is configured to restrict movement of the arm body 16 relative to the crankshaft 14 along the axis of rotation A1. The shaft bolt 28 is for attachment to the crankshaft 14. The shaft bolt 28 is configured to attach to a slotted end 24 of the crankshaft 14. The crankshaft 14 includes an internal thread 14A. The slotted end 24 includes an internal thread 14A. The shaft bolt 28 is configured to engage with the internal thread 14A of the crankshaft 14.

[0052] As shown in Figure 4, the shaft bolt 28 includes a bolt body 30 and a radial protrusion 32. The bolt body 30 has an external thread 30A, configured to engage with the internal thread 14A of the crankshaft 14 in an installed state where the crank arm 12 is mounted to the crankshaft 14. The radial protrusion 32 extends radially outward from the bolt body 30 relative to a first opening axis A2. The radial protrusion 32 is configured to abut against the arm body 16 in an axial direction D2 relative to the first opening axis A2 in the installed state. Therefore, the arm body 16 is held in the axial direction D2 between the shaft bolt 28 and a bottom bracket 2B of the vehicle body 2A. At least one spacer may be provided and / or desired to be positioned in the axial direction D2 between the arm body 16 and the bottom bracket 2B.

[0053] As shown in Figure 2, the arm body 16 includes a shaft fastener receiving opening 34. The shaft fastener receiving opening 34 has a second opening axis A3 that is not parallel to the first opening axis A2. The shaft fastener receiving opening 34 is partially connected to the crankshaft receiving opening 22 via a connecting opening 36. The connecting opening 36 is located on the periphery 26 of the bolt groove in the arm body 16.

[0054] The crank arm 12 of the crank assembly 10 for the human-powered vehicle 2 includes a shaft fastener 38 and a biasing element 40. The shaft fastener 38 is configured to be inserted into a shaft fastener receiving opening 34. The biasing element 40 is configured to be inserted into a shaft fastener receiving opening 34.

[0055] As shown in Figure 5, the shaft fastener 38 is configured to engage with the bolt groove end 24 of the crankshaft 14 in one of the inserted states where the shaft fastener 38 is inserted into the shaft fastener receiving opening 34. The biasing element 40 is configured to bias the shaft fastener 38 in one of the states where the shaft fastener 38 and the biasing element 40 are inserted into the shaft fastener receiving opening 34.

[0056] The shaft fastener 38 includes a fastener body 42 having a bolt groove portion 44. The bolt groove portion 44 is configured to engage with the bolt groove end 24 of the crankshaft 14 in an installed state in which the crank arm 12 is mounted to the crankshaft 14. The bolt groove portion 44 is configured to engage with the bolt groove end 24 of the crankshaft 14 in a state in which the inner periphery 26 of the bolt groove engages with the bolt groove end 24 of the crankshaft 14.

[0057] The biasing element 40 is configured to bias the shaft fastener 38 in a bias direction D3 parallel to the second opening axis A3. The biasing element 40 may contact one end of the fastener body 42 of the shaft fastener 38 to bias the fastener body 42 of the shaft fastener 38 in the bias direction D3. The biasing element 40 is configured to apply a biasing force F1 to the shaft fastener 38 in the bias direction D3. The biasing element 40 is configured to bias the crankshaft 14 via the shaft fastener 38 in a rotational bias direction D4.

[0058] In the first embodiment, the bias direction D3 is opposite to the rotational drive direction D1 of the crank arm 12. The rotational bias direction D4 is opposite to the rotational drive direction D1 of the crank arm 12. However, the bias direction D3 may be the same as the rotational drive direction D1 of the crank arm 12 as needed and / or desired. The bias direction D3 may be a direction not along the rotational drive direction D1 of the crank arm 12 as needed and / or desired. The rotational bias direction D4 may be the same as the rotational drive direction D1 of the crank arm 12 as needed and / or desired.

[0059] As shown in Figure 5, the biasing element 40 has an external thread 40A. The arm body 16 has an internal thread 34A formed in the shaft fastener receiving opening 34. The internal thread 34A is configured to engage with the external thread 40A of the biasing element 40.

[0060] The biasing element 40 includes a tool engagement member 40B with which it engages to rotate the biasing element 40 relative to the arm body 16. The tool engagement member 40B includes a tool engagement hole 40C, such as a hexagonal socket. In a first embodiment, the biasing element 40 includes a hexagonal socket screw with external threads 40A. Therefore, the biasing element 40 may also refer to a biasing screw or biasing bolt 40. However, the biasing element 40 may, as needed and / or desired, include other structures to replace or supplement a screw.

[0061] As shown in Figure 5, the shaft fastener receiving opening 34 includes an insertion hole 34B and a threaded hole 34C. For example, the insertion hole 34B includes an unthreaded hole. The insertion hole 34B is partially connected to the crankshaft receiving opening 22 via a connecting opening 36. An internal thread 34A defines the threaded hole 34C. The threaded hole 34C communicates with the insertion hole 34B. The external thread 40A of the biasing element 40 is configured to engage with the threaded hole 34C of the shaft fastener receiving opening 34. The shaft fastener 38 is configured to be disposed in the insertion hole 34B of the shaft fastener receiving opening 34.

[0062] In the first embodiment, the second opening axis A3 is spaced apart from the first opening axis A2. The second opening axis A3 is defined by a tangent along a circumferential direction D6 relative to the first opening axis A2. However, the positional relationship between the first opening axis A2 and the second opening axis A3 is not limited to the relationship shown.

[0063] As shown in Figure 5, the bolt groove portion 44 includes at least one internal bolt groove tooth 44A. In the first embodiment, the bolt groove portion 44 includes a plurality of internal bolt groove teeth 44A arranged circumferentially around the first opening axis A2. The plurality of internal bolt groove teeth 44A of the bolt groove portion 44 are configured to engage with a plurality of external teeth 24A of the bolt groove end 24 of the crankshaft 14.

[0064] As shown in Figures 3 and 5, in the first embodiment, the total number of one of the plurality of inner pin teeth 44A in the pin groove portion 44 differs from the total number of one of the plurality of outer teeth 24A in the pin groove end 24. The total number of the plurality of inner pin teeth 44A in the pin groove portion 44 is less than the total number of one of the plurality of outer teeth 24A in the pin groove end 24. The total number of the plurality of inner pin teeth 44A in the pin groove portion 44 is 6, while the total number of one of the plurality of outer teeth 24A in the pin groove end 24 is 38. However, the total number of the plurality of inner pin teeth 44A in the pin groove portion 44 may be greater than or equal to the total number of one of the plurality of outer teeth 24A in the pin groove end 24 as needed and / or desired. The total number of the plurality of inner pin teeth 44A in the pin groove portion 44 is not limited to the above-mentioned number.

[0065] As shown in Figures 3 and 5, in the first embodiment, the total number of the plurality of inner pin groove teeth 44A in the pin groove portion 44 is different from the total number of the plurality of inner teeth 26A in the inner periphery 26 of the pin groove. The total number of the plurality of inner pin groove teeth 44A in the pin groove portion 44 is less than the total number of the plurality of inner teeth 26A in the inner periphery 26 of the pin groove. The total number of the plurality of inner pin groove teeth 44A in the pin groove portion 44 is 6, while the total number of the plurality of inner teeth 26A in the inner periphery 26 of the pin groove is 38. However, the total number of the plurality of inner pin groove teeth 44A in the pin groove portion 44 may be greater than or equal to the total number of the plurality of inner teeth 26A in the inner periphery 26 of the pin groove as needed and / or desired. The total number of the plurality of inner pin groove teeth 44A in the pin groove portion 44 is not limited to the above-mentioned number.

[0066] As shown in Figure 3, the plurality of external teeth 24A at the bolt end 24 includes a first external tooth 24A1, a plurality of second external teeth 24A2, and a third external tooth 24A3. Each of the first external tooth 24A1 and the third external tooth 24A3 has a circumferential width different from that of the second external tooth 24A2. The circumferential width of each of the first external tooth 24A1 and the third external tooth 24A3 is greater than the circumferential width of the second external tooth 24A2. However, the circumferential width of at least one of the first external tooth 24A1 and the third external tooth 24A3 may, as needed and / or desired, be less than or equal to the circumferential width of the second external tooth 24A2. In a first embodiment, the circumferential width of the first external tooth 24A1 is equal to the circumferential width of the third external tooth 24A3. However, the circumferential width of the first external tooth 24A1 may be different from the circumferential width of the third external tooth 24A3.

[0067] As shown in Figure 6, the plurality of inner bolt groove teeth 44A includes a first inner bolt groove tooth 44B1, a first inner bolt groove tooth 44C1, a second inner bolt groove tooth 44B2, a second inner bolt groove tooth 44C2, a third inner bolt groove tooth 44B3, and a third inner bolt groove tooth 44C3. In the state where the bolt groove portion 44 of the central shaft fastener 38 is engaged with the bolt groove end 24 of the crankshaft 14, a first external tooth 24A1 is disposed between the first inner bolt groove tooth 44B1 and the first inner bolt groove tooth 44C1. In the state where the bolt groove portion 44 of the central shaft fastener 38 is engaged with the bolt groove end 24 of the crankshaft 14, one tooth of the plurality of second external teeth 24A2 is disposed between the first inner bolt groove tooth 44B1 and the second inner bolt groove tooth 44B2. In the state where the groove portion 44 of the shaft fastener 38 is engaged with the groove end 24 of the crankshaft 14, another tooth of the plurality of second external teeth 24A2 is disposed between the second inner groove tooth 44B2 and the third inner groove tooth 44B3. In the state where the groove portion 44 of the shaft fastener 38 is engaged with the groove end 24 of the crankshaft 14, another tooth of the plurality of second external teeth 24A2 is disposed between the first inner groove tooth 44C1 and the second inner groove tooth 44C2. In the state where the groove portion 44 of the shaft fastener 38 is engaged with the groove end 24 of the crankshaft 14, another tooth of the plurality of second external teeth 24A2 is disposed between the second inner groove tooth 44C2 and the third inner groove tooth 44C3.

[0068] As shown in Figure 7, the bolt groove portion 44 of the fastener body 42 is configured to overlap with the connection opening 36 in the inserted state where the shaft fastener 38 is inserted into the shaft fastener receiving opening 34, so as to engage with the bolt groove end 24 of the crankshaft 14. The bolt groove portion 44 of the fastener body 42 is configured to be exposed through the connection opening 36 to the crankshaft receiving opening 22 so as to engage with the bolt groove end 24 of the crankshaft 14 in the inserted state.

[0069] The inner periphery 26 of the bolt groove has a first axial width W1 defined in the axial direction D2. The inner periphery 26 of the bolt groove has a first reference center plane CP1 defined to bisect the first axial width W1 in the axial direction D2. The first reference center plane CP1 is perpendicular to the first opening axis A2.

[0070] The connecting opening 36 has a second axial width W2 defined in the axial direction D2. The connecting opening 36 has a second reference center plane CP2 defined to bisect the second axial width W2 in the axial direction D2. The second reference center plane CP2 is perpendicular to the first opening axis A2 and parallel to the second opening axis A3.

[0071] The arm body 16 includes a first axial surface 16C and a second axial surface 16D. The second axial surface 16D is disposed on the opposite side of one of the first axial surfaces 16C in the axial direction D2. The second axial surface 16D is closer to the bottom bracket 2B of the vehicle body 2A in the axial direction D2 than the first axial surface 16C.

[0072] In the first embodiment, the second opening axis A3 is offset from the first reference center surface CP1 of the inner periphery 26 of the bolt groove in the axial direction D2. The second reference center surface CP2 is also offset from the first reference center surface CP1 of the inner periphery 26 of the bolt groove in the axial direction D2. The second opening axis A3 is disposed on the second reference center surface CP2.

[0073] The second opening axis A3 and the second reference center surface CP2 are offset in the axial direction D2 from the first reference center surface CP1 of the inner periphery 26 of the bolt groove toward the second axial surface 16D. The second opening axis A3 and the second reference center surface CP2 are disposed in the axial direction D2 between the first reference center surface CP1 and the second axial surface 16D.

[0074] However, at least one of the second opening axis A3 and the second reference center surface CP2 may be offset in the axial direction D2 from the first reference center surface CP1 of the inner periphery 26 of the bolt groove toward the first axial surface 16C as needed and / or desired.

[0075] At least one of the second opening axis A3 and the second reference center surface CP2 may be disposed in the axial direction D2 between the first reference center surface CP1 and the first axial surface 16C, as needed and / or as desired. At least one of the second opening axis A3 and the second reference center surface CP2 may be disposed in the axial direction D2 on the first reference center surface CP1 of the inner periphery 26 of the bolt groove, as needed and / or as desired. The second opening axis A3 may be offset from the second reference center surface CP2 in the axial direction D2, as needed and / or as desired.

[0076] As shown in Figure 8, the plurality of internal teeth 26A includes a first internal tooth 26B1, a first internal tooth 26C1, a second internal tooth 26B2, a second internal tooth 26C2, a third internal tooth 26B3, and a third internal tooth 26C3.

[0077] The first internal tooth 26B1 is disposed in one of the circumferential positions of the first internal bolt groove tooth 44B1 of the same bolt groove portion 44. The first internal tooth 26B1 and the first internal bolt groove tooth 44B1 constitute a single bolt groove tooth.

[0078] The first internal tooth 26C1 is disposed in one of the circumferential positions of the first internal bolt groove tooth 44C1 of the same bolt groove portion 44. The first internal tooth 26C1 and the first internal bolt groove tooth 44C1 constitute a single bolt groove tooth.

[0079] The second internal tooth 26B2 is disposed in one of the circumferential positions of the second internal bolt groove tooth 44B2 of the same bolt groove portion 44. The second internal tooth 26B2 and the second internal bolt groove tooth 44B2 constitute a single bolt groove tooth.

[0080] The second internal tooth 26C2 is disposed in one of the circumferential positions of the second internal bolt groove tooth 44C2 of the same bolt groove portion 44. The second internal tooth 26C2 and the second internal bolt groove tooth 44C2 constitute a single bolt groove tooth.

[0081] The third internal tooth 26B3 is disposed in one of the circumferential positions of the third internal bolt groove tooth 44B3 of the same bolt groove portion 44. The third internal tooth 26B3 and the third internal bolt groove tooth 44B3 constitute a single bolt groove tooth.

[0082] The third internal tooth 26C3 is disposed in one of the circumferential positions of the third internal bolt groove tooth 44C3 of the same bolt groove portion 44. The third internal tooth 26C3 and the third internal bolt groove tooth 44C3 constitute a single bolt groove tooth.

[0083] The first internal tooth 26B1 is divided into first teeth 26B11 and 26B12 by the connecting opening 36. The first internal tooth 26C1 is divided into first teeth 26C11 and 26C12 by the connecting opening 36. The second internal tooth 26B2 is divided into second teeth 26B21 and 26B22 by the connecting opening 36. The second internal tooth 26C2 is divided into second teeth 26C21 and 26C22 by the connecting opening 36. The third internal tooth 26B3 is divided into third teeth 26B31 and 26B32 by the connecting opening 36. The third internal tooth 26C3 is divided into third teeth 26C31 and 26C32 by the connecting opening 36.

[0084] A first inner pin groove tooth 44B1 is disposed between first teeth 26B11 and 26B12 in the axial direction D2 to form a single pin groove tooth. A first inner pin groove tooth 44C1 is disposed between first teeth 26C11 and 26C12 in the axial direction D2 to form a single pin groove tooth. A second inner pin groove tooth 44B2 is disposed between second teeth 26B21 and 26B22 in the axial direction D2 to form a single pin groove tooth. A second inner pin groove tooth 44C2 is disposed between second teeth 26C21 and 26C22 in the axial direction D2 to form a single pin groove tooth. A third inner pin groove tooth 44B3 is disposed between third teeth 26B31 and 26B32 in the axial direction D2 to form a single pin groove tooth. A third inner pin groove tooth 44C3 is disposed between third teeth 26C31 and 26C32 in the axial direction D2 to form a single pin groove tooth.

[0085] As shown in Figure 9, when viewed from a projection direction D5 (see, for example, Figure 3) that is radially defined relative to the first opening axis A2 and perpendicular to the second opening axis A3, the first opening axis A2 of the crankshaft receiving opening 22 is not parallel to the second opening axis A3 of the shaft fastener receiving opening 34. When viewed from a projection direction D5 (see, for example, Figure 5) that is radially defined relative to the first opening axis A2 and perpendicular to the second opening axis A3, the first opening axis A2 of the crankshaft receiving opening 22 is perpendicular to the second opening axis A3 of the shaft fastener receiving opening 34.

[0086] The shaft fastener 38 further includes a positioning structure 50 configured to position the fastener body 42 in the inserted state. In a first embodiment, the positioning structure 50 includes a movable member 52, a biasing member 54, and a receiving chamber 56.

[0087] The movable member 52 is movable relative to the fastener body 42. The movable member 52 can contact the inner peripheral surface of one of the insertion holes 34B of the shaft fastener receiving opening 34. In a first embodiment, the movable member 52 includes a curved convex surface 52A. The movable member 52 has a spherical shape. For example, the movable member 52 includes a sphere. However, the movable member 52 may have other shapes as needed and / or desired.

[0088] As shown in Figure 9, the biasing member 54 is configured to bias the movable member 52 in a direction away from the fastener body 42. The biasing member 54 is configured to bias the movable member 52 radially outward relative to the second opening axis A3 in the inserted state. A receiving chamber 56 is formed to the fastener body 42 and configured to receive the movable member 52 and the biasing member 54. The fastener body 42 includes the receiving chamber 56. The movable member 52 is movably disposed in the receiving chamber 56. The biasing member 54 is disposed in the receiving chamber 56 to bias the movable member 52. In a first embodiment, the biasing member 54 includes a spring, such as a compression spring. However, the biasing member 54 may, as needed and / or desired, include other structures to replace or supplement a spring.

[0089] The positioning structure 50 further includes a receiving groove 58 formed to the arm body 16 and configured to receive one of the movable members 52. The arm body 16 includes the receiving groove 58. The peripheral surface within the insertion hole 34B of the shaft fastener receiving opening 34 includes the receiving groove 58. The receiving groove 58 includes a curved concave surface 58A. However, the receiving groove 58 may have other shapes, such as a groove, as needed and / or desired.

[0090] The shaft fastener 38 includes a tool engagement portion 60 with which it engages a tool. The tool engagement portion 60 includes a tool engagement hole 60A, such as a hexagonal socket. The tool engagement portion 60 is located at one end of the fastener body 42 and configured to allow a user to use a tool (such as a hexagonal wrench) to adjust the position of the shaft fastener 38 relative to the periphery 26 of the bolt groove in the arm body 16.

[0091] As seen in Figures 10 and 11, the shaft fastener receiving opening 34 has a circular cross-section. As seen in Figure 10, the insertion hole 34B of the shaft fastener receiving opening 34 has a circular cross-section. The fastener body 42 of the shaft fastener 38 has a circular cross-section. As seen in Figure 11, the threaded hole 34C of the shaft fastener receiving opening 34 has a circular cross-section. The biasing element 40 has a circular cross-section. However, the cross-section of the shaft fastener receiving opening 34 may have another shape, such as a polygonal shape and an elliptical shape, as needed and / or desired. The cross-section of the insertion hole 34B may have another shape, such as a polygonal shape and an elliptical shape, as needed and / or desired. The cross-section of the threaded hole 34C may have another shape, such as a polygonal shape and an elliptical shape, as needed and / or desired. The cross-section of the fastener body 42 of the shaft fastener 38 may have another shape, such as a polygonal shape and an elliptical shape, as needed and / or desired. The cross-section of the biasing element 40 may have another shape, such as a polygonal shape and an elliptical shape, as needed and / or desired. The tool engagement portion 60 may be omitted from the self-shaft fastener 38 as needed and / or desired.

[0092] As shown in Figure 12, the external teeth 24A of the bolt groove end 24 include a circumferential surface 24AS facing a rotational direction opposite to the rotational drive direction D1. The circumferential surface 24AS faces the rotational bias direction D4. The internal teeth 26A of the inner periphery 26 of the bolt groove includes a circumferential surface 26AS facing the rotational drive direction D1. The circumferential surface 24AS of the external teeth 24A of the bolt groove end 24 can contact the circumferential surface 26AS of the internal teeth 26A of the inner periphery 26 of the bolt groove. The biasing force F1 of the biasing element 40 biases the crankshaft 14 relative to the arm body 16 in the rotational bias direction D4 via the bolt groove portion 44 of the fastener body 42. The biasing force F1 of the biasing element 40 causes the circumferential surface 24AS of the external teeth 24A to be in close contact with the circumferential surface 26AS of the internal teeth 26A. Therefore, in the state where the biasing element 40 biases the shaft fastener 38 in the biasing direction D3, the biasing element 40 keeps the circumferential surface 24AS of the external teeth 24A of the crankshaft 14 in contact with the circumferential surface 26AS of the internal teeth 26A of the arm body 16. Therefore, the pedal force applied to the arm body 16 is efficiently transmitted from the arm body 16 to the crankshaft 14 via the periphery 26 of the latch groove in the arm body 16 and the latch groove end 24 of the crankshaft 14. Second Embodiment

[0093] The following description refers to Figures 13 to 15 to illustrate a crank assembly 210 including a crank arm 212 according to a second embodiment. Except for the shaft fasteners, the crank arm 212 has the same structure and / or configuration as the crank arm 12. Therefore, elements having substantially the same function as those in the first embodiment will be numbered the same here, and for the sake of brevity, will not be described in detail or illustrated further.

[0094] As shown in Figure 13, the crank arm 212 of the crank assembly 210 for the human-powered vehicle 2 includes an arm body 16, a shaft fastener 238, and a biasing element 40. The crank arm 212 further includes a shaft bolt 28. The shaft fastener 238 has a structure substantially identical to that of the shaft fastener 38 described in the first embodiment.

[0095] As shown in Figure 14, the shaft fastener 238 is configured to be inserted into the shaft fastener receiving opening 34. The shaft fastener 238 is configured to engage with the bolt groove end 24 of the crankshaft 14 in one of the inserted states in which the shaft fastener 238 is inserted into the shaft fastener receiving opening 34.

[0096] In the second embodiment, the shaft fastener 238 includes a fastener body 242 having a bolt groove portion 44. The bolt groove portion 44 is configured to engage with the bolt groove end 24 of the crankshaft 14 in an installed state in which the crank arm 212 is mounted to the crankshaft 14. The fastener body 242 has a structure substantially identical to that of the fastener body 42 described in the first embodiment.

[0097] The biasing element 40 is configured to bias the shaft fastener 238 in a biasing direction D3 parallel to the second opening axis A3. The biasing element 40 may contact one end of the fastener body 242 of the shaft fastener 238 to bias the fastener body 242 of the shaft fastener 238 in the biasing direction D3. The biasing element 40 is configured to bias the crankshaft 14 via the shaft fastener 238 in the rotational biasing direction D4.

[0098] As shown in Figure 15, the shaft fastener 238 further includes a positioning structure 250 configured to position the fastener body 242 in the inserted state. In this embodiment, the positioning structure 250 includes an elastic ring 252 and an annular groove 254.

[0099] An annular groove 254 is formed into the fastener body 242 and configured to receive an elastic ring 252. The elastic ring 252 is disposed in the annular groove 254. The elastic ring 252 can contact the peripheral surface inside the insertion hole 34B of the shaft fastener receiving opening 34.

[0100] The elastic ring 252 is made of an elastic material (such as rubber). The elastic ring 252 elastically deforms in the inserted state where the shaft fastener 238 is inserted into the shaft fastener receiving opening 34. Therefore, the positioning structure 250 is configured to apply resistance to restrict movement of the fastener body 242 relative to the arm body 16. In the second embodiment, the receiving groove 58 described in the first embodiment is omitted from the arm body 16. However, the arm body 16 may, as needed and / or desired, include the receiving groove 58 as in the first embodiment. Third Embodiment

[0101] The following description, with reference to FIG16, describes a crank assembly 310 including a crank arm 312 according to a third embodiment. Except for the shaft fasteners and biasing elements, the crank arm 312 has the same structure and / or configuration as crank arms 12 or 212. Therefore, elements having substantially the same function as those in the first and / or second embodiments will be numbered the same herein and, for the sake of brevity, will not be described in detail or illustrated further.

[0102] As shown in Figure 5, in the first embodiment, the fastener body 42 of the shaft fastener 38 is formed as a single, integral component. As shown in Figure 13, in the second embodiment, the fastener body 242 of the shaft fastener 238 is formed as a single, integral component. However, the fastener body 42 of the shaft fastener 38 may, as needed and / or desired, include a plurality of individual components. The fastener body 242 of the shaft fastener 238 may, as needed and / or desired, include a plurality of individual components.

[0103] As shown in Figure 16, the crank arm 312 of the crank assembly 310 of the human-powered vehicle 2 includes an arm body 16, a shaft fastener 338, and a biasing element 340. The shaft fastener 338 is configured to be inserted into a shaft fastener receiving opening 34. The shaft fastener 338 includes a fastener body 342 having a latching portion 344. The latching portion 344 is configured to engage with the latching end 24 of the crank shaft 14 in the mounted state where the crank arm 312 is mounted to the crank shaft 14.

[0104] The fastener body 342 includes a first fastener body 370 and a second fastener body 372. The second fastener body 372 is a component separate from the first fastener body 370. The bolt groove portion 344 includes a first bolt groove portion 374 and a second bolt groove portion 376. The second bolt groove portion 376 is a component separate from the first bolt groove portion 374. The first fastener body 370 includes the first bolt groove portion 374. The second fastener body 372 includes the second bolt groove portion 376.

[0105] The biasing element 340 is configured to bias the shaft fastener 338 in a biasing direction D3 parallel to the second opening axis A3. The biasing element 340 may contact one end of the fastener body 342 of the shaft fastener 338 to bias the fastener body 342 of the shaft fastener 338 in the biasing direction D3. The biasing element 340 is configured to bias the crankshaft 14 via the shaft fastener 338 in the rotational biasing direction D4.

[0106] The biasing element 340 is configured to bias the first fastener body 370 in the biasing direction D3. The biasing element 340 may contact one end of the first fastener body 370 to bias the fastener body 342 of the shaft fastener 338 in the biasing direction D3. The biasing element 340 is configured to bias the second fastener body 372 in an additional biasing direction D7 opposite to the biasing direction D3.

[0107] The biasing element 340 has an external thread 340A. The shaft fastener 338 includes an internal thread 338A configured to engage with the external thread 340A of the biasing element 340. The second fastener body 372 includes an internal thread 338A. The second fastener body 372 includes a threaded hole 372A extending along the second opening axis A3. The internal thread 338A defines the threaded hole 372A. The first fastener body 370 includes a hole 370A extending along the second opening axis A3. The hole 370A includes an unthreaded hole. The shaft fastener receiving opening 34 includes an insertion hole 34B. In a third embodiment, the shaft fastener receiving opening 34 does not have the internal thread 34A and threaded hole 34C described in the first embodiment.

[0108] As shown in Figure 16, the shaft fastener 338 further includes positioning structures 350A and / or 350B configured to position the fastener body 342 in the inserted state. The shaft fastener 338 further includes positioning structures 350A and 350B. Positioning structure 350A is configured to position the first fastener body 370 relative to the arm body 16 in the inserted state. Positioning structure 350B is configured to position the second fastener body 372 relative to the arm body 16 in the inserted state. Each of positioning structures 350A and 350B has a structure substantially identical to that of positioning structure 250 described in the second embodiment. However, the positioning structure 50 described in the first embodiment may be applied to the shaft fastener 338 as needed and / or desired to replace or supplement the positioning structure 250 of the second embodiment.

[0109] In the third embodiment, the positioning structure 350A includes an elastic ring 352A and an annular groove 354A. The positioning structure 350B includes an elastic ring 352B and an annular groove 354B. Each of the elastic rings 352A and 352B has a structure substantially identical to that of the elastic ring 252 described in the second embodiment. Each of the annular grooves 354A and 354B has a structure substantially identical to that of the annular groove 254 described in the second embodiment.

[0110] An annular groove 354A is formed into the fastener body 342 and configured to receive a resilient ring 352A. The first fastener body 370 includes the annular groove 354A. The resilient ring 352A is disposed in the annular groove 354A. The resilient ring 352A can contact the peripheral surface within the insertion hole 34B of the shaft fastener receiving opening 34.

[0111] An annular groove 354B is formed into the fastener body 342 and configured to receive a resilient ring 352B. A second fastener body 372 includes the annular groove 354B. The resilient ring 352B is disposed within the annular groove 354B. The resilient ring 352B can contact the peripheral surface within the insertion hole 34B of the shaft fastener receiving opening 34.

[0112] The biasing element 340 includes a tool engaging member 40B having a tool engaging hole 40C. The biasing element 340 includes a rod 340B and a head 340C. The rod 340B includes an external thread 340A. The head 340C is disposed at one end of the rod 340B. The rod 340B extends from the head 340C. The rod 340B extends through a hole 370A in the first fastener body 370.

[0113] The shaft fastener 338 includes a tool engagement portion 360 and / or 362 that engages with a tool. Each of the tool engagement portions 360 and 362 has a structure substantially identical to that of the tool engagement portion 60 in the first and second embodiments.

[0114] The tool engagement portion 360 includes a tool engagement hole 360A, such as a hexagonal socket. The tool engagement portion 360 is located at one end of the first fastener body 370 and configured to allow a user to use a tool (such as a hexagonal wrench) to adjust the position of the first fastener body 370 relative to the periphery 26 of the bolt groove in the arm body 16. The tool engagement hole 360A communicates with the hole 370A. However, the tool engagement portion 360 may be omitted from the first fastener body 370 of the self-shaping fastener 338 if needed and / or desired.

[0115] The tool engagement portion 362 includes a tool engagement hole 362A, such as a hexagonal socket. The tool engagement portion 362 is located at one end of the second fastener body 372 and configured to allow a user to use a tool (such as a hex wrench) to adjust the position of the first fastener body 370 relative to the periphery 26 of the bolt groove in the arm body 16. The tool engagement hole 362A communicates with the threaded hole 372A. However, the tool engagement portion 362 may be omitted from the second fastener body 372 of the self-shaping fastener 338 if needed and / or desired.

[0116] In this application, as used herein, the term "comprising" and its derivatives are intended to be open-ended terms, specifically referring to the presence of the stated features, elements, components, groups, wholes, and / or steps, but not excluding the presence of other unstated features, elements, components, groups, wholes, and / or steps. This concept also applies to terms with similar meanings, such as the terms "having," "comprising," and their derivatives.

[0117] The terms “component,” “section,” “part,” “part,” “element,” “body,” and “structure” used in the singular can have a dual meaning of a single component or a plurality of components.

[0118] The ordinal numbers described in this application (such as "first" and "second") are merely identifiers and have no other meaning (e.g., a specific order or similar). Furthermore, for example, the term "first element" does not imply the existence of "second element," and the term "second element" does not imply the existence of "first element."

[0119] As used herein, the term "a pair of..." can refer to configurations in which a pair of elements have the same shape or structure as each other, or configurations in which a pair of elements have different shapes or structures from each other.

[0120] The terms "a", "one or more" and "at least one" are used interchangeably in this document.

[0121] As used in this invention, the phrase "at least one of..." means "one or more" of the choices to be made. For example, as used in this invention, if the number of choices is two, the phrase "at least one of..." means "only one single choice" or "all two choices". For another example, as used in this invention, if the number of choices is equal to or greater than three, the phrase "at least one of..." means "only one single choice" or "any combination equal to or greater than two choices". For example, the phrase "at least one of A and B" covers (1) only A, (2) only B, and (3) both A and B. The phrase "at least one of A, B, and C" covers (1) only A, (2) only B, (3) only C, (4) both A and B, (5) both B and C, (6) both A and C, and (7) all A, B, and C. In other words, the phrase "at least one of A and B" in this invention does not mean "at least one of A and at least one of B".

[0122] Finally, as used herein, degree terms (such as “substantially,” “about,” and “approximately”) mean a reasonable amount of deviation from the modified term that does not materially alter the final result. All numerical values ​​described in this application may be interpreted as including terms such as “substantially,” “about,” and “approximately.”

[0123] It is obvious that many modifications and variations of the invention can be made in light of the foregoing teachings. Therefore, it should be understood that the invention can be practiced in ways other than those specifically described herein, within the scope of the appended claims.

[0124] 2: Human-powered vehicles 2A: Vehicle body 2B: Bottom bracket 10: Crank assembly 12: Crank arm 14: Crankshaft 14A: Internal thread 16: Arm Body 16A: First longitudinal end 16B: Second longitudinal end 16C: First axial surface 16D: Second axial surface 16H: Pedal attachment hole 22: Crankshaft receiving opening 24: Bolt slot end 24A: External teeth 24A1: First external tooth 24A2: Second external tooth 24A3: Third external tooth 24AS: Circumferential surface 26: Peripheral area inside the bolt groove 26A: Internal teeth 26AS: Circumferential surface 26B1: First internal tooth 26B2: Second internal tooth 26B3: Third internal tooth 26B11: First tooth 26B12: First tooth 26B21: Second tooth 26B22: Second tooth 26B31: Third tooth 26B32: Third tooth 26C1: First internal tooth 26C2: Second internal tooth 26C3: Third internal tooth 26C11: First tooth 26C12: First tooth 26C21: Second tooth 26C22: Second tooth 26C31: Third tooth 26C32: Third tooth 28: Shaft bolts 30: Bolt body 30A: External thread 32: Radial convex part 34: Shaft fastener receiving opening 34A: Internal thread 34B: Insertion Hole 34C: Threaded hole 36: Connection opening 38: Shaft Fasteners 40: Bias element 40A: External thread 40B: Tool engagement component 40C: Tool engagement hole 42: Fastener body 44: Bolt groove section 44A: Internal stud tooth 44B1: First internal stud tooth 44B2: Second internal stud tooth 44B3: Third internal stud tooth 44C1: First internal stud tooth 44C2: Second internal stud tooth 44C3: Third internal stud tooth 50: Positioning Structure 52: Movable components 52A: Curved convex surface 54: Offset component 56: Reception Room 58: Receiving groove 58A: Curved concave surface 60: Tool engagement part 60A: Tool engagement hole 210: Crank assembly 212: Crank arm 238: Shaft Fasteners 242: Fastener body 250: Positioning Structure 252: Elastic Ring 254: Annular groove 310: Crank assembly 312: Crank arm 338: Shaft Fastener 338A: Internal thread 340: Bias element 340A: External thread 340B: Rod 340C: Head 342: Fastener body 344: Bolt groove section 350A: Positioning Structure 350B: Positioning Structure 352A: Elastic Ring 352B: Elastic Ring 354A: Annular groove 354B: Annular groove 360: Tool engagement part 360A: Tool Engagement Hole 362: Tool engagement part 362A: Tool Engagement Hole 370: First fastener body 370A: Hole 372: Second fastener body 372A: Threaded hole 374: First bolt groove section 376: Second bolt groove section A1: Axis of rotation A2: First opening axis A3: Second opening axis CP1: First reference center plane CP2: Second Reference Center Plane D1: Rotation drive direction D2: Axial direction D3: Offset Direction D4: Rotational bias direction D5: Projection Direction D6: Circumferential direction D7: Additional Offset Direction F1: Bias Force W1: First axial width W2: Second axial width

Claims

1. A crank arm for a crank assembly in a human-powered vehicle, comprising: An arm body includes: a crankshaft receiving opening having a first opening axis and a grooved periphery configured to receive and engage a grooved end of a crankshaft; and a shaft fastener receiving opening having a second opening axis not parallel to the first opening axis, the shaft fastener receiving opening being connected to a portion of the crankshaft receiving opening via a connecting opening; a shaft fastener configured to be inserted into the shaft fastener receiving opening and including a fastener body having a grooved portion configured to engage with the grooved end of the crankshaft in an installed state in which the crank arm is mounted to the crankshaft; and a biasing element configured to bias the shaft fastener in a biasing direction parallel to the second opening axis, the grooved portion of the fastener body configured to overlap the connecting opening and engage with the grooved end of the crankshaft in an inserted state in which the shaft fastener is inserted into the shaft fastener receiving opening. The biasing element has an external thread, and the arm body has an internal thread formed in the shaft fastener receiving opening and configured to engage with the external thread of the biasing element.

2. The crank arm of claim 1, wherein when viewed from a projection direction that is radially defined relative to the first opening axis and perpendicular to the second opening axis, the first opening axis of the crankshaft receiving opening is perpendicular to the second opening axis of the shaft fastener receiving opening.

3. The crank arm of claim 1 further includes: A shaft bolt comprising: a bolt body having an external thread configured to engage with an internal thread of the crankshaft in the mounted state; and a radial protrusion extending radially outward from the bolt body relative to a first opening axis and configured to abut against the arm body in one of the axial directions relative to the first opening axis in the mounted state.

4. The crank arm of claim 1, wherein the shaft fastener further includes a positioning structure configured to position the fastener body in the inserted state.

5. The crank arm of claim 4, wherein the positioning structure further includes a receiving groove formed to the arm body and configured to receive a movable member.

6. The crank arm of claim 4, wherein the positioning structure comprises: a resilient ring; and an annular groove formed to the fastener body and configured to receive the resilient ring.

7. The crank arm of claim 1, wherein the bias direction is opposite to one of the rotational drive directions of the crank arm.

8. The crank arm of claim 1, wherein the fastener body of the shaft fastener is formed as an integral single-piece component.

9. The crank arm of claim 8, wherein the biasing element can contact one end of the fastener body of the shaft fastener to bias the fastener body of the shaft fastener in the biasing direction.

10. A crank arm for a crank assembly in a human-powered vehicle, comprising: An arm body includes: a crankshaft receiving opening having a first opening axis and a grooved periphery configured to receive and engage a grooved end of a crankshaft; and a shaft fastener receiving opening having a second opening axis not parallel to the first opening axis, the shaft fastener receiving opening being connected to a portion of the crankshaft receiving opening via a connecting opening; a shaft fastener configured to be inserted into the shaft fastener receiving opening and including a fastener body having a grooved portion configured to engage with the grooved end of the crankshaft in an installed state in which the crank arm is mounted to the crankshaft; and a biasing element configured to bias the shaft fastener in a biasing direction parallel to the second opening axis, the grooved portion of the fastener body configured to overlap the connecting opening and engage with the grooved end of the crankshaft in an inserted state in which the shaft fastener is inserted into the shaft fastener receiving opening. The shaft fastener further includes a positioning structure configured to position the fastener body in the inserted state, the positioning structure including: a movable member; a biasing member configured to bias the movable member in a direction away from the fastener body; and a receiving chamber formed to the fastener body and configured to receive the movable member and the biasing member.

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