A bicycle crank

Abstract

A bicycle crank includes a crank and a positioning disc claw located at the large end of the crank. An internal spline is machined in the center of the positioning disc claw, and a spline sleeve is detachably mounted thereon. A positioning groove is machined at the large end of the crank. A boss extends radially from the center of one side of the positioning disc claw to form a boss that fits into the positioning groove. An external spline is machined on the outer side of the spline sleeve to match the internal spline. An internal spline I is machined on the inner side of the spline sleeve. Side grooves I and II are machined at the junction of the spline sleeve and the positioning disc claw. Side grooves I and II together form a hole for a positioning screw to pass through. The positioning screw passes through side grooves I and II and is screwed into the crank for fixation. This structure, by machining an internal spline in the center of the positioning disc claw and detachably mounting a spline sleeve, allows the crank to be adapted to different sizes of bottom brackets, providing good versatility.

Description

Technical Field

[0001] This utility model relates to a bicycle crank. Background Technology

[0002] The crank assembly of a bicycle is mainly composed of various interconnected transmission components, including a bottom bracket, two cranks, and a chainring. The bottom bracket is typically mounted at the bottom bracket tube, with cranks attached to both ends of the bottom bracket, and then secured by the bottom bracket. Currently, the cranks and bottom bracket are generally connected using fixed dimensions; that is, a bottom bracket size can only be fitted to a specific crank, resulting in poor versatility between components. Utility Model Content

[0003] To address the shortcomings mentioned above, this utility model provides a bicycle crank.

[0004] To achieve the above objectives, this utility model provides a bicycle crank, including a crank and a positioning disc claw disposed at the large end of the crank, wherein an internal spline is machined in the middle of the positioning disc claw and a spline sleeve is detachably installed.

[0005] A positioning groove is machined at the large end of the crank. A boss is formed by radially extending from the middle of one side of the positioning disc claw and fitting into the positioning groove. An external spline is machined on the outer side of the spline sleeve to match the internal spline. An internal spline I is machined on the inner side of the spline sleeve. A side groove I and a side groove are machined at the junction of the spline sleeve and the positioning disc claw. The side groove I and the side groove surround to form a hole for the positioning screw to pass through. After the positioning screw passes through the side groove I and the side groove, it is screwed into and fixed to the crank.

[0006] As a further improvement of this utility model, a keyway is machined on the inner wall of the positioning groove, the keyway is evenly distributed along the circumference of the positioning groove, and a key block is provided on the outer side of the boss, which corresponds one-to-one with the keyway.

[0007] As a further improvement of this utility model, the side groove I and the end of the side groove away from the crank are respectively machined with a stepped portion I and a stepped portion, the stepped portion I and the stepped portion forming a space for accommodating the head of the positioning screw.

[0008] As a further improvement of this utility model, a through hole is machined at the center of the positioning groove, and a connecting sleeve is formed by radially extending the edge of the through hole toward the positioning disk claw side.

[0009] As a further improvement of this utility model, positioning holes are uniformly machined near the edge of the positioning disk claw for connection and positioning with the toothed disk.

[0010] As a further improvement of this utility model, a threaded hole is machined at the small end of the crank for mounting the foot pedal.

[0011] The beneficial effects of this utility model are as follows:

[0012] This structure allows the crank to be adapted to shafts of different sizes by machining internal splines in the middle of the positioning disc claw and detachably installing spline sleeves, thus providing good versatility. Attached Figure Description

[0013] Figure 1 This is a front view of a bicycle crank according to the present invention;

[0014] Figure 2 for Figure 1 Sectional view along line AA in the middle;

[0015] Figure 3 This is the front view of crank 1;

[0016] Figure 4 This is a rear view of the positioning disc claw 2;

[0017] Figure 5 This is the main view of spline sleeve 3.

[0018] In the diagram: 1. Crank; 11. Threaded hole; 12. Locating groove; 13. Keyway; 14. Through hole; 15. Connecting sleeve; 2. Locating disc claw; 21. Locating hole; 22. Boss; 23. Key block; 24. Internal spline; 25. Side groove; 26. Step; 3. Spline sleeve; 31. Internal spline I; 32. External spline; 33. Side groove I; 34. Step I; 4. Locating screw. Detailed Implementation

[0019] like Figure 1-2 As shown, the present invention provides a bicycle crank, including a crank 1 and a positioning disc claw 2 located at the large end of the crank 1. The positioning disc claw 2 has an internal spline 24 machined in the middle and a spline sleeve 3 detachably installed.

[0020] A positioning groove 12 is machined at the large end of crank 1, and a threaded hole 11 is machined at the small end of crank 1 for mounting foot pedals (see...). Figure 3 The positioning claw 2 extends radially from the center of one side to form a boss 22, which fits into the positioning groove 12. A keyway 13 is machined on the inner wall of the positioning groove 12, and the keyways 13 are evenly distributed along the circumference of the positioning groove 12. A key block 23 is provided on the outer side of the boss 22, corresponding one-to-one with the keyway 13 (see...). Figure 4 The outer spline 32 of the spline sleeve 3 is machined on its outer side to match the inner spline 24, and the inner spline I 31 is machined on the inner side of the spline sleeve 3 (see...). Figure 5At the junction of the spline sleeve 3 and the positioning claw 2, there are corresponding side grooves I33 and 25. The side grooves I33 and 25 form a hole for the positioning screw 4 to pass through. After the positioning screw 4 passes through the side grooves I33 and 25, it is screwed and fixed with the crank 1. The side grooves I33 and 25 away from the crank 1 are respectively machined with stepped parts I34 and 26. The stepped parts I34 and 26 form a space for accommodating the head of the positioning screw 4. A through hole 14 is machined at the center of the positioning groove 12. The edge of the through hole 14 extends radially toward the positioning claw 2 to form a connecting sleeve 15. Positioning holes 21 are uniformly machined near the edge of the positioning claw 2 for connection and positioning with the gear plate.

[0021] This structure allows the crank to be adapted to shafts of different sizes by machining internal splines in the middle of the positioning disc claw and detachably installing spline sleeves, thus providing good versatility.

[0022] For ease of understanding, this utility model will be described in conjunction with the accompanying drawings for practical use:

[0023] During use, the size of the bottom bracket determines whether a spline sleeve needs to be installed. If the size of the bottom bracket end matches the size of the inner spline at the center of the positioning disc claw, a spline sleeve is not required. During assembly, first connect the positioning disc claw to the gear plate. Then, insert the boss on one side of the positioning disc claw into the positioning groove at the large end of the crank. The key block on the outside of the boss engages with the keyway on the inner wall of the positioning groove to restrict the circumferential rotation of the positioning disc claw. Finally, connect and position the positioning disc claw to the crank using positioning screws. If the size of the bottom bracket end is small and matches the size of the inner spline I on the inside of the spline sleeve, a spline sleeve needs to be installed. First, connect the positioning disc claw to the gear disc. Then, insert the boss on one side of the positioning disc claw into the positioning groove at the large end of the crank. The key block on the outside of the boss and the keyway on the inner wall of the positioning groove are engaged and positioned to restrict the circumferential rotation of the positioning disc claw. Next, install a spline sleeve on the inner spline of the positioning disc claw. The outer spline on the outer side of the spline sleeve corresponds to the inner spline of the positioning disc claw, and the side groove I on the outer side of the spline sleeve corresponds to the side groove on the inner side of the positioning disc claw. Finally, the positioning screw passes through the side groove I and the side groove and is screwed into the crank to fix it, thereby connecting and positioning the spline sleeve and the positioning disc claw to the crank at the same time.

[0024] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A bicycle crank, characterized by: Includes a crank (1) and a positioning disc claw (2) located at the large end of the crank (1). The positioning disc claw (2) has an internal spline (24) machined in the middle and a spline sleeve (3) can be detachably installed. The crank (1) has a positioning groove (12) machined at its large end. The positioning disc claw (2) extends radially from the middle of one side to form a boss (22) which fits into the positioning groove (12). The outer side of the spline sleeve (3) is machined with an outer spline (32) that matches the inner spline (24). The inner side of the spline sleeve (3) is machined with an inner spline I (31). The spline sleeve (3) and the positioning disc claw (2) are machined with a side groove I (33) and a side groove (25) respectively. The side groove I (33) and the side groove (25) surround each other to form a hole for the positioning screw (4) to pass through. The positioning screw (4) passes through the side groove I (33) and the side groove (25) and then screws into the crank (1) for fixation.

2. A bicycle crank as claimed in claim 1, characterized in that: The positioning groove (12) has a keyway (13) machined on its inner wall. The keyway (13) is evenly distributed along the circumference of the positioning groove (12). The outer side of the boss (22) is provided with a key block (23) that corresponds one-to-one with the keyway (13).

3. A bicycle crank as claimed in claim 1, characterized in that: The side groove I (33) and the side groove (25) are respectively machined with a stepped portion I (34) and a stepped portion (26) at the ends away from the crank (1). The stepped portion I (34) and the stepped portion (26) enclose a space for accommodating the head of the positioning screw (4).

4. A bicycle crank as defined in claim 1, characterized in that: A through hole (14) is machined at the center of the positioning groove (12), and a connecting sleeve (15) is formed by radially extending the edge of the through hole (14) toward the positioning claw (2).

5. A bicycle crank as defined in claim 1, characterized in that: The positioning claw (2) has uniformly machined positioning holes (21) near its edge for connection and positioning with the gear plate.

6. A bicycle crank as defined in claim 1, characterized in that: The crank (1) has a threaded hole (11) machined at its small end for mounting the foot pedal.

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