Adjustable length bicycle crank and sprocket linkage

Abstract

The utility model belongs to the technical field of bicycle accessories, and disclose adjustable length's bicycle crank and sprocket linkage structure, including crank axle, crank rod, sprocket, pad piece and the adjusting disc that is equipped with multiple groups of gear hole, the both ends of crank rod are respectively with the end of adjusting disc rotation connection and the end of installing pedal, and multiple groups of mounting holes are equipped on the end of installing pedal. Through rotating crank rod makes the gear butt joint hole on crank rod and target gear hole on adjusting disc alignment, inserts gear pin and fixes to change crank rod angle, or switches the installation position of pedal in different mounting hole, can all adjust the distance of adjusting disc axle center to pedal axle center, realizes the effective length adjustment of crank, the structure need not to dismantle core part to be able to flexibly adjust crank length, convenient operation can adapt to different height user and city slow ride, mountainous area speed competition etc. Multi -scene demand, improve cycling comfort and power efficiency.

Description

Technical Field

[0001] This utility model relates to the field of bicycle accessories technology, specifically to an adjustable-length bicycle crank and sprocket linkage structure. Background Technology

[0002] In a bicycle's drivetrain, the crank, as the core component connecting the bottom bracket and pedals, directly affects the rider's power efficiency, comfort, and performance. It is a key parameter for adapting to different riders and usage scenarios. Currently, most mainstream bicycle cranks on the market adopt a fixed length design, producing various crank sizes such as 165mm, 170mm, and 175mm based on common rider heights and needs, allowing consumers to choose when purchasing a bicycle or replacing parts. However, this fixed-length design has significant limitations, making it difficult to meet the diverse and dynamic needs of consumers. On the one hand, novice bicycle users often lack a clear understanding of their own riding needs, relying heavily on experience recommendations or standard specifications when choosing crank lengths, easily leading to the problem of "crank length not matching their own needs." If a user mistakenly chooses a short crank, their legs cannot fully extend during pedaling, potentially causing knee discomfort over long periods; if they mistakenly choose a long crank, excessive leg movement increases the risk of sports injuries. Once users realize the compatibility issue, they need to purchase new crank parts and replace them using specialized tools, increasing both time and financial costs, and the process is also quite cumbersome. On the other hand, with the popularization of cycling culture, more and more users are switching between using the same bicycle in different scenarios, such as daily slow urban riding and weekend mountain biking, commuting and fitness training. The requirements for crank length vary drastically depending on the scenario: slow urban riding requires comfort and is suitable for medium-length cranks; mountain biking emphasizes power and requires slightly longer cranks. However, the existing method of disassembling and replacing cranks cannot quickly respond to the needs of scenario switching. If users want to use suitable cranks in different scenarios, they either have to carry multiple sets of crank accessories or frequently disassemble and install them, which is highly complex and seriously affects the riding experience. Utility Model Content

[0003] To address the shortcomings of existing technologies, this utility model provides an adjustable-length bicycle crank and sprocket linkage structure to solve the problems mentioned in the background art, such as the fixed length of existing bicycle cranks and the difficulty in adjustment.

[0004] To achieve the above-mentioned objectives, this utility model provides the following technical solution: an adjustable-length bicycle crank and sprocket linkage structure, comprising: Crankset bottom bracket, which is installed in the bottom bracket of the bicycle; Two sets of cranks are located on the left and right sides of the crankshaft. The sprocket is located on one side of the crankshaft and has multiple sets of teeth. The sprocket is connected to the chain drive through the teeth. Two sets of pads are provided, which are located between the crank shaft and the crank arm. One set of pads is equipped with a pawl, and the sprocket is coaxially connected to the pad through the pawl. Two sets of adjustment discs are provided. The adjustment discs are located on the side of the pad that is away from the crank shaft. The adjustment discs are provided with multiple gear holes.

[0005] Preferably, the crank rod is a rigid strip structure, with a first end and a second end at its two ends. The first end is rotatably connected to the adjustment disc, and a pedal is installed on the second end.

[0006] Preferably, a rotating hole is provided at the first end, and a crank shaft sleeve is provided on the adjusting plate, with the first end sleeved on the crank shaft sleeve.

[0007] Preferably, a crankshaft bushing fixing member is provided on the side of the crankshaft bushing away from the adjusting disc, and the crankshaft bushing is rotatably connected to the adjusting disc through the crankshaft bushing fixing member.

[0008] Preferably, the axis of the crankshaft bushing does not coincide with the axis of the adjusting disc.

[0009] Preferably, the second end is provided with multiple sets of pedal mounting holes, which are aligned with the crankshaft bushing, and the distances between the multiple sets of pedal mounting holes and the crankshaft bushing are not equal.

[0010] Preferably, the multiple sets of shift holes are equidistant from the crankshaft bushing, and the multiple sets of shift holes are distributed in an arc around the crankshaft bushing.

[0011] Preferably, the crank arm is provided with a set of gear engagement holes, and the distance between the gear engagement holes and the crank arm shaft sleeve is equal to the distance between the gear hole and the crank arm shaft sleeve.

[0012] Preferably, a detachable gear shift pin is provided in the gear shift docking hole, and the gear shift pin passes through the gear shift docking hole and a set of gear shift holes.

[0013] Compared with the prior art, this utility model provides an adjustable length bicycle crank and sprocket linkage structure, which has the following advantages: This adjustable-length bicycle crank and sprocket linkage structure includes a crank bottom bracket, crank arm, sprocket, pad, adjustment disc, gear hole, crank arm pivot sleeve, gear docking hole, and gear pin. By changing the angle of the crank arm and the installation position of the pedals, the distance between the pedals and the center of the adjustment disc is changed, thus altering the effective length of the crank. It is suitable for consumers of different heights and habits, meeting the complex needs of consumers in various scenarios. It is easy to adjust, offers multiple adjustment methods, and is highly practical. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the overall structure of this utility model; Figure 3 This is a schematic diagram of the adjusting disc and crankshaft structure of this utility model; Figure 4 This is an axial view of the overall structure of this utility model.

[0015] In the diagram: 1. Crankshaft; 2. Crankshaft; 3. Sprocket; 4. Pad; 5. Disc claw; 6. Adjustment disc; 7. Gear hole; 8. First end; 9. Second end; 10. Crankshaft pivot sleeve; 11. Pivot sleeve fixing piece; 12. Pedal mounting hole; 13. Gear docking hole; 14. Gear pin. Detailed Implementation

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] Please see Figure 1-4 The present invention provides the following technical solution: The adjustable-length bicycle crank and sprocket linkage mechanism includes: Crank shaft 1 is installed in the bottom bracket of a bicycle. The type and specific model of crank shaft 1 are not limited. Common square hole, spline, and bearing shafts are all suitable.

[0018] Two sets of cranks 2 are located on the left and right sides of the crank shaft 1. The sprocket 3 is located on one side of the crank shaft 1. The sprocket 3 has multiple sets of teeth and is connected to the chain drive through the teeth. Two sets of pads 4 are provided, and the pads 4 are located between the crank shaft 1 and the crank shank 2. One set of pads 4 is provided with a disc claw 5. The sprocket 3 is coaxially connected to the pads 4 through the disc claw 5. Two sets of adjustment discs 6 are provided, with the adjustment discs 6 located on the side of the pad 4 opposite to the crank shaft 1. Multiple sets of position holes 7 are provided on the adjustment discs 6. The combination of the adjustment discs 6 and the crank lever 2 is equivalent to a conventional bicycle crank. In this invention, the adjustment discs 6 are equipped with a mounting and fixing structure that cooperates with the crank shaft 1. The crank lever 2 is connected to the crank shaft 1 via the adjustment discs 6, and the posture of the crank lever 2 can be adjusted via the adjustment discs 6 to change the effective length of the crank.

[0019] Furthermore, the crank lever 2 is a rigid strip structure, with a first end 8 and a second end 9 at its two ends. The first end 8 is rotatably connected to the adjusting disc 6, and a pedal is installed on the second end 9.

[0020] Furthermore, a rotating hole is provided at the first end 8, and a crank shaft sleeve 10 is provided on the adjusting plate 6, with the first end 8 sleeved on the crank shaft sleeve 10.

[0021] Furthermore, a crankshaft bushing 10 is provided with a bushing fixing member 11 on the side opposite to the adjusting plate 6, and the crankshaft bushing 10 is rotatably connected to the adjusting plate 6 through the bushing fixing member 11.

[0022] Furthermore, the axis of the crankshaft bushing 10 does not coincide with the axis of the adjusting disc 6.

[0023] Furthermore, multiple sets of pedal mounting holes 12 are provided at the second end 9. These multiple sets of pedal mounting holes 12 are aligned with the crankshaft bushing 10, and the distances between the multiple sets of pedal mounting holes 12 and the crankshaft bushing 10 are all unequal. The effective length of the crank is the distance from the axis of the adjusting disc 6 to the axis of the pedal. The pedal can be installed in a suitable pedal mounting hole 12, thus realizing the adjustment of the effective length of the crank.

[0024] Furthermore, the multiple sets of gear shift holes 7 are equidistant from the crankshaft sleeve 10, and the multiple sets of gear shift holes 7 are distributed in an arc around the crankshaft sleeve 10.

[0025] Furthermore, a set of gear engagement holes 13 are provided on the crank lever 2, and the distance between the gear engagement holes 13 and the crank lever shaft sleeve 10 is equal to the distance between the gear hole 7 and the crank lever shaft sleeve 10.

[0026] Furthermore, a detachable gear shift pin 14 is provided inside the gear shift docking hole 13, and the gear shift pin 14 passes through the gear shift docking hole 13 and a set of gear shift holes 7. The entire crank lever 2 can rotate around the crank lever pivot sleeve 10, and can be fixed in the corresponding gear position by using the gear shift pin 14 (threaded fixing is recommended for the gear shift pin 14), which can change the angle of the crank lever 2, change the distance between the axis of the adjustment disc 6 and the pedal, that is, change the effective length of the crank, making adjustment simple and convenient.

[0027] Structural Description: Crank shaft 1: The core drive shaft component installed in the bottom bracket of the bicycle. The type is not limited (such as square hole, spline, and bearing shaft are all applicable). It is used to connect the pads 4 on both sides and provides the installation base and the central shaft for power transmission of the entire linkage structure. Crank lever 2: A rigid strip-shaped force-bearing component with a first end 8 and a second end 9 at its two ends. The first end 8 is rotatably connected to the adjustment disc 6, and the second end 9 is used to install the pedals. The lever body is provided with a gear docking hole 13, which is the key to transmitting pedaling force and realizing length adjustment. Sprocket 3: A transmission component with multiple sets of teeth located on one side of the crank shaft 1. It is coaxially connected to the pad 4 via the pawl 5. It transmits the power transmitted by the crank to the rear wheel of the bicycle by meshing with the chain through the teeth. Pad 4: A connecting component between crank shaft 1 and crank shank 2, consisting of two groups. One group is equipped with a pawl 5, which is used to connect crank shaft 1, adjusting disc 6 and sprocket 3, serving as a transition connection and axial positioning function. Claw 5: A connecting structure set on a set of pads 4, used to fix the sprocket 3 and the pads 4 coaxially, ensuring that the sprocket 3 rotates synchronously with the pads 4, and realizing the transmission of power from the pads 4 to the sprocket 3; Adjustment disc 6: A disc-shaped component located on the side of the pad 4 away from the crank shaft 1. It has multiple sets of gear holes 7 and crank rod shaft sleeve 10. After being assembled with the crank rod 2, it is equivalent to a part of a traditional crank. It is used to connect the crank rod 2 and provide a gear base for its angle adjustment. Gear hole 7: A multi-group hole structure formed on the adjusting plate 6 and distributed in an arc around the crank shaft sleeve 10. Each group of holes is equidistant from the crank shaft sleeve 10. It is used to cooperate with the gear pin 14 and the gear docking hole 13 to fix the adjustment angle of the crank 2. First end 8: The end structure located at one end of the crank 2 has a rotating hole, which is used to fit onto the crank spool sleeve 10 of the adjusting disc 6, so as to realize the rotational connection between the crank 2 and the adjusting disc 6. Second end 9: The end structure located at the other end of the crank lever 2, which is provided with multiple sets of pedal mounting holes 12 for mounting pedals. The effective length of the crank can be finely adjusted by switching the position of the pedals in different mounting holes. Crank rod pivot sleeve 10: A sleeve-shaped structure set on the adjusting plate 6, with a pivot sleeve fixing part 11 on the side opposite to the adjusting plate 6. Its axis does not coincide with the axis of the adjusting plate 6, and it is used to fit the first end 8 of the crank rod 2, providing a pivot sleeve support for the rotation of the crank rod 2. Rotary shaft sleeve fixing component 11: A fixing component provided on the side of the crank shaft sleeve 10 away from the adjusting plate 6, used to rotatably connect the crank shaft sleeve 10 and the adjusting plate 6, ensuring that the rotating shaft sleeve is stably installed and can rotate; Pedal mounting holes 12: Multiple sets of hole-like structures are formed on the second end 9, which are aligned with the crankshaft bushing 10. The distances of each set of holes from the crankshaft bushing 10 are not equal, and they are used to install pedals to adjust the distance between the pedals and the bushing. Gear positioning hole 13: A single set of hole-like structures opened on the crank stalk 2. Its distance from the crank stalk shaft sleeve 10 is equal to the distance from the gear positioning hole 7 to the shaft sleeve. It is used to cooperate with the gear positioning pin 14 and the gear positioning hole 7 to fix the angle of the crank stalk 2. Gear pin 14: A detachable pin-shaped component that can pass through the gear docking hole 13 of the crank lever 2 and a set of gear holes 7 of the adjustment disc 6, used to fix the relative angle between the crank lever 2 and the adjustment disc 6, and to achieve locking after the crank length is adjusted.

[0028] Working principle: During assembly, the crankshaft 1 is fixed inside the bicycle's bottom bracket. Adjustment discs 6 are connected to both sides via pads 4. The left adjustment disc 6 is directly assembled to the crank arm 2, while the right adjustment disc 6 is coaxially fixed to the sprocket 3 via a pawl 5, forming a complete transmission chain. When the rider needs to adjust the crank length, this can be achieved through two coordinated mechanisms: The first adjustment mechanism is achieved by changing the relative angle between the crank lever 2 and the adjustment disc 6. The first end 8 of the crank lever 2 is sleeved onto the crank lever shaft sleeve 10 of the adjustment disc 6 through a rotating hole. Since the axis of the crank lever shaft sleeve 10 does not coincide with the axis of the adjustment disc 6 (there is an eccentricity), the crank lever 2 can rotate freely around the crank lever shaft sleeve 10. Multiple sets of gear holes 7 are distributed around the crank lever shaft sleeve 10 on the adjustment disc 6, and the distance from each set of gear holes 7 to the crank lever shaft sleeve 10 is equal. Correspondingly, the crank lever 2 has a set of gear engagement holes 13, whose distance from the crank lever shaft sleeve 10 is consistent with the distance parameter of the gear holes 7. When the crank lever 2 is rotated to the target angle, the gear engagement hole 13 will precisely align with a certain set of gear holes 7. At this time, inserting the gear pin 14 through both will fix the crank lever 2 in that gear position. Since the axis of the adjusting disc 6 is fixed (coaxial with the crank shaft 1), and the pedal is installed at the second end 9 of the crank lever 2, this angle adjustment will change the straight distance from the axis of the adjusting disc 6 to the pedal through the eccentric structure, thereby achieving the first step of adjusting the effective length of the crank.

[0029] The second adjustment mechanism is achieved by changing the mounting position of the pedals at the second end 9. Multiple sets of pedal mounting holes 12 are provided on the second end 9 of the crankshaft 2. These holes are distributed along the length of the crankshaft 2 and are all aligned with the crankshaft bushing 10, but the distances from each set of pedal mounting holes 12 to the crankshaft bushing 10 are unequal. When the pedal is switched from one mounting hole to another, its distance from the crankshaft bushing 10 changes. Combined with the fixed eccentricity parameter from the first mechanism, the final distance from the center of the adjustment disc 6 to the pedal (i.e., the effective length of the crank) can be further finely adjusted.

[0030] When the two adjustment mechanisms work together, the appropriate gear is first selected by rotating the crank lever 2 (changing the angle and basic eccentricity), and then the length is finely adjusted by switching the pedal mounting holes 12, ultimately achieving multi-gear, wide-range crank length adjustment. After adjustment, the pedaling force is transmitted to the crank lever 2 through the pedals, causing the adjustment disc 6 to rotate synchronously. The adjustment disc 6 drives the crank shaft 1 to rotate, and through the disc claws 5 of the pad 4, it drives the sprocket 3 to rotate, completing the power output through the meshing of the teeth with the chain. The entire adjustment process does not require disassembling core components such as the crank shaft 1 and sprocket 3; it can be achieved simply by inserting and removing the gear pins 14 and reinstalling the pedals. The operation is convenient and can accurately adapt to the needs of users of different heights or diverse riding scenarios.

[0031] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An adjustable-length bicycle crank and sprocket linkage structure, characterized in that, include: Crank shaft (1), the crank shaft (1) is installed in the bottom bracket of the bicycle; Two sets of cranks (2) are located on the left and right sides of the crank shaft (1); The sprocket (3) is located on one side of the crank shaft (1). The sprocket (3) has multiple sets of teeth and is connected to the chain drive through the teeth. Two sets of pads (4) are provided between the crank shaft (1) and the crank rod (2). A pawl (5) is provided on one set of pads (4). The sprocket (3) is coaxially connected to the pads (4) through the pawl (5). Two sets of adjustment discs (6) are provided on the side of the pad (4) away from the crank shaft (1). Multiple sets of gear holes (7) are provided on the adjustment discs (6).

2. The adjustable-length bicycle crank and sprocket linkage structure according to claim 1, characterized in that, The crank rod (2) is a rigid strip structure. The two ends of the crank rod (2) are a first end (8) and a second end (9), respectively. The first end (8) is rotatably connected to the adjustment plate (6), and a foot pedal is installed on the second end (9).

3. The adjustable-length bicycle crank and sprocket linkage structure according to claim 2, characterized in that, A rotating hole is provided at the first end (8), and a crank shaft sleeve (10) is provided on the adjusting plate (6). The first end (8) is sleeved on the crank shaft sleeve (10).

4. The adjustable-length bicycle crank and sprocket linkage structure according to claim 3, characterized in that, The crankshaft bushing (10) is provided with a bushing fixing member (11) on the side away from the adjustment plate (6), and the crankshaft bushing (10) is rotatably connected to the adjustment plate (6) through the bushing fixing member (11).

5. The adjustable-length bicycle crank and sprocket linkage structure according to claim 4, characterized in that, The axis of the crankshaft sleeve (10) does not coincide with the axis of the adjusting disc (6).

6. The adjustable-length bicycle crank and sprocket linkage structure according to claim 3, characterized in that, The second end (9) is provided with multiple sets of pedal mounting holes (12), which are aligned with the crank shaft sleeve (10), and the distances between the multiple sets of pedal mounting holes (12) and the crank shaft sleeve (10) are not equal.

7. The adjustable-length bicycle crank and sprocket linkage structure according to claim 3, characterized in that, The multiple gear shift holes (7) are equidistant from the crankshaft sleeve (10), and the multiple gear shift holes (7) are arranged in an arc around the crankshaft sleeve (10).

8. The adjustable-length bicycle crank and sprocket linkage structure according to claim 7, characterized in that, A set of gear docking holes (13) are provided on the crank rod (2), and the distance between the gear docking hole (13) and the crank rod shaft sleeve (10) is equal to the distance between the gear hole (7) and the crank rod shaft sleeve (10).

9. The adjustable-length bicycle crank and sprocket linkage structure according to claim 8, characterized in that, The gear docking hole (13) is provided with a detachable gear pin (14), which passes through the gear docking hole (13) and a set of gear holes (7).

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