Bicycle power mechanism with lengthened crank

Abstract

The utility model relates to the technical field of bicycle power transmission, and discloses a bicycle power mechanism with a lengthened crank. The mechanism comprises a chain wheel, a flywheel and a chain connecting the chain wheel and the flywheel, two ends of a chain wheel fixing shaft are symmetrically connected with a first crank and a second crank, the cranks are connected with driving parts, the driving parts are connected with a bicycle frame through positioning parts, and the other ends of the driving parts are connected with pedal assemblies. A first circle center formed by movement of the pedal assembly is located above a second circle center formed at the connecting position of the driving piece and the crank and in front of the advancing direction of the bicycle, the acting point of the pedal is changed through the double-circle-center track design, the traditional movement track is broken, the crankset is driven according to the lever principle, and the crankset can be arranged under a cushion or at the position close to the rear of the cushion; the distance between the pedal and the flywheel is shortened, the labor-saving effect is achieved when the pedal movement diameter is kept about 340 mm, meanwhile, the pedal point is changed through the structural design of the driving piece, and the design space is expanded.

Description

Technical Field

[0001] This utility model relates to the field of bicycle power transmission technology, and in particular to a bicycle power mechanism with an extender crank. Background Technology

[0002] In the field of bicycles, the design of the power transmission mechanism directly affects the effort required for riding, energy conversion efficiency, and the overall layout of the bicycle. The traditional bicycle power transmission system mainly consists of a chainring, freewheel, chain, and crank. Its working principle is that the pedals drive the crank to rotate around the central axis of the chainring, and then the power is transmitted to the freewheel through the chain to achieve wheel drive.

[0003] In existing technology, traditional bicycles typically place the chainring under the saddle, forward, to meet the power demands of pedaling, and the crank length is fixed (generally around 170mm). The pedals move in a circular motion around the center of the chainring. This structural design has the following technical drawbacks:

[0004] Firstly, the forward position of the chainring results in a larger chain span between the chainring and the freewheel, which not only increases the chain length but also makes the chain prone to shaking during operation, leading to it falling off and increasing wear on the chain and chainring.

[0005] Secondly, the existing crank structure design lacks flexibility and is difficult to optimize for personalized power characteristics for riders of different heights and leg lengths or different riding scenarios (such as racing and commuting), which limits the product's adaptability.

[0006] To address these issues, some existing technologies attempt to enhance effort-saving performance by increasing crank length. However, simply increasing crank length leads to a larger pedal travel diameter (e.g., exceeding 340mm), disrupting riding rhythm and potentially causing new problems such as frame imbalance. Other technologies shorten chain length by changing chainring position, but without simultaneously optimizing the pedaling mechanism, the resulting power delivery is unnatural and difficult to widely adopt. Therefore, we propose a bicycle powertrain with an extended crank to solve these shortcomings. Utility Model Content

[0007] The purpose of this invention is to solve the problems of how to make the pedal's circumferential motion diameter remain unchanged while achieving greater effort reduction and increasing the design space of the pedal mechanism, and proposes a bicycle power mechanism with an extended crank.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A bicycle power mechanism with an extender crank includes a chainring and a freewheel. A chain connects the chainring and the freewheel. A fixed shaft is connected to the chainring. One end of the fixed shaft is connected to a first crank, and the other end is connected to a second crank. The first and second cranks are symmetrically arranged. A drive member is connected to both the first and second cranks. One end of the drive member is connected to the bicycle frame via a positioning member, and the other end is connected to a pedal assembly. The pedal assembly rotates in a circular motion to form a first center. The connection between the drive member and the first and second cranks rotates in a circular motion to form a second center. The first center is located above the second center and is located in front of the second center along the direction of travel of the bicycle.

[0010] In a preferred embodiment of this utility model, the driving component includes a first extension rod a connected to the first crank, one end of the first extension rod a being connected to a second extension rod a, the second extension rod a being bent upwards at an obtuse angle relative to the first extension rod a; and a first extension rod b connected to the second crank, one end of the first extension rod b being connected to a second extension rod b, the second extension rod b being bent upwards at an obtuse angle relative to the first extension rod b; wherein the two obtuse angles are the same, and both the first extension rod a and the first extension rod b are connected to the bicycle frame through the positioning component.

[0011] In a preferred embodiment of the present invention, the foot pedal assembly includes a first foot pedal installed at the end of the second extension rod a away from the first extension rod a, and a second foot pedal installed at the end of the second extension rod b away from the first extension rod b.

[0012] In a preferred embodiment of this utility model, the positioning component for positioning the first extension rod a includes: a connecting plate a for mounting on a bicycle frame; a sliding sleeve a, wherein a rotating connector a connects the sliding sleeve a and the connecting plate a, the sliding sleeve a rotating on the connecting plate a via the rotating connector a, and the first extension rod a slidably disposed with respect to the sliding sleeve a; the positioning component for positioning the first extension rod b includes: a connecting plate b for mounting on a bicycle frame; a sliding sleeve b, wherein a rotating connector b connects the sliding sleeve b and the connecting plate b, the sliding sleeve b rotating on the connecting plate b via the rotating connector b, and the first extension rod b slidably disposed with respect to the sliding sleeve b.

[0013] In a preferred embodiment of this utility model, the connecting plate a is provided with a connecting hole a, and the connecting plate b is provided with a connecting hole b.

[0014] In a preferred embodiment of the present invention, the first extension rod a is provided with a first sliding groove, the inner side of the sliding sleeve a is provided with a slider a that cooperates with the first sliding groove, the first extension rod b is provided with a second sliding groove, and the inner side of the sliding sleeve b is provided with a slider b that cooperates with the second sliding groove.

[0015] In a preferred embodiment of the present invention, the first groove passes through the end of the first extension rod a, and the end of the first extension rod a is detachably connected to a first baffle; the second groove passes through the end of the first extension rod b, and the end of the first extension rod b is detachably connected to a second baffle.

[0016] In a preferred embodiment of the present invention, the end of the first crank away from the chainring is connected to a first connecting shaft, and the connection between the first extension rod a and the second extension rod a is rotatably connected to the first connecting shaft; the end of the second crank away from the chainring is connected to a second connecting shaft, and the connection between the first extension rod b and the second extension rod b is rotatably connected to the second connecting shaft.

[0017] Compared with the prior art, this utility model provides a bicycle power mechanism with an extender crank, which has the following advantages:

[0018] This invention can change the pedal force point, breaking the original pedal movement trajectory of a bicycle. When riding, the pedal assembly is subjected to force and acts on the drive component, driving the first and second cranks through the lever principle, thereby driving the chainring. Compared with traditional bicycles, where the chainring is positioned far forward below the saddle for easy pedaling, this solution adds an elongated crank, allowing the chainring to be positioned directly below or slightly behind the saddle. This shortens the relative distance between the chainring and the freewheel, increases the distance between the pedal force point and the chainring, and achieves a more effortless technical effect by utilizing the lever principle. By designing the structure of the drive component, the pedal point can be changed, unlike the traditional fixed pedal position, allowing for greater design flexibility. Attached Figure Description

[0019] Figure 1 A schematic diagram of the structure of a bicycle power mechanism with an extender crank proposed in this utility model. Figure 1 ;

[0020] Figure 2 A schematic diagram of the structure of a bicycle power mechanism with an extender crank proposed in this utility model. Figure 2 ;

[0021] Figure 3 This utility model proposes a bicycle power mechanism with an extender crank. Figure 2 A schematic diagram of the structure of part A;

[0022] Figure 4 A schematic diagram of the structure of a bicycle power mechanism with an extender crank proposed in this utility model. Figure 3 ;

[0023] Figure 5 This utility model proposes a bicycle power mechanism with an extender crank. Figure 4 A structural diagram of section B;

[0024] Figure 6 This is a front view of a bicycle power mechanism with an extender crank proposed in this utility model;

[0025] Figure 7 A top view of a bicycle power mechanism with an extender crank proposed in this utility model;

[0026] Figure 8 Right view of a bicycle power mechanism with an extender crank proposed in this utility model;

[0027] Figure 9 A schematic diagram of the circular motion trajectory of the original bicycle crank and pedal points;

[0028] Figure 10 This is a schematic diagram of the circumferential running trajectory structure of the pedal point of a bicycle power mechanism with an extending crank proposed in this utility model.

[0029] In the diagram: 100, chainring; 101, freewheel; 102, chain; 103, fixed shaft; 104, first crank; 105, second crank; 200, first connecting shaft; 201, first extension rod a; 202, second extension rod a; 203, first pedal; 204, first slide groove; 205, first baffle; 300, second connecting shaft; 301, first extension rod b; 302, second extension rod b; 303, second pedal; 304, second slide groove; 305, second baffle; 400, connecting plate a; 401, connecting hole a; 402, sliding sleeve a; 403, slider a; 404, rotating connector a; 500, connecting plate b; 501, connecting hole b; 502, sliding sleeve b; 503, slider b; 504, rotating connector b; 600, first center; 700, second center. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0031] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0032] Reference Figures 1-8 A bicycle power mechanism with an extendable crank includes a chainring 100 and a freewheel 101. A chain 102 connects the chainring 100 and the freewheel 101. A fixed shaft 103 is connected to the chainring 100. One end of the fixed shaft 103 is connected to a first crank 104, and the other end is connected to a second crank 105. The first crank 104 and the second crank 105 are symmetrically arranged. A drive unit is connected to both the first crank 104 and the second crank 105. One end of the drive unit is connected to the bicycle frame through a positioning member, and the other end is connected to a pedal assembly. The pedal assembly rotates in a circular motion to form a first center 600. The connection between the drive unit and the first crank 104 and the second crank 105 rotates in a circular motion to form a second center 700. The first center 600 is located above the second center 700 and is located in front of the second center 700 along the direction of bicycle travel.

[0033] By adopting the above solution, the pedal force point can be changed, breaking the original pedal movement trajectory of the bicycle. When riding, the pedal assembly is subjected to force and acts on the drive component, driving the first crank 104 and the second crank 105 to move through the lever principle, thereby realizing the drive of the chainring 100. Compared with traditional bicycles, the chainring 100 is positioned slightly forward below the saddle to facilitate pedaling. However, this solution, by adding an extended crank, allows the chainring 100 to be positioned directly below or slightly behind the saddle, shortening the relative distance between the chainring 100 and the freewheel 101. The crank length of a traditional bicycle is about 170mm, and with the chainring center as the axis, the diameter is about 340mm for one pedal stroke. This solution increases the distance between the pedal force point and the chainring 100, maintaining a diameter of about 340mm for one pedal stroke. By utilizing the lever principle, a more effort-saving technical effect is achieved. This utility model can change the pedal point by designing the structure of the drive component, which is different from the traditional fixed pedal point position and has greater design flexibility.

[0034] In a preferred embodiment, the drive component includes a first extension rod a201 connected to a first crank 104, with a second extension rod a202 connected to one end of the first extension rod a201, the second extension rod a202 being bent upwards at an obtuse angle relative to the first extension rod a201; and a first extension rod b301 connected to a second crank 105, with the second extension rod b302 connected to one end of the first extension rod b301, the second extension rod b302 being bent upwards at an obtuse angle relative to the first extension rod b301; wherein the two obtuse angles are the same, and both the first extension rod a201 and the first extension rod b301 are connected to the bicycle frame through positioning components. Taking the connection of the first extension rod a201 and the second extension rod a202 as an example, the first extension rod a201 and the second extension rod a202 can be connected by integral bending, welding, or mechanical splicing, and the included angle between the first extension rod a201 and the second extension rod a202 is preferably 135 degrees. The connection method of the first extension rod b301 and the second extension rod b302 is the same as that of the first extension rod a201 and the second extension rod a202, and will not be described in detail again.

[0035] In a preferred embodiment, the foot pedal assembly includes a first foot pedal 203 mounted on the end of the second extension rod a202 away from the first extension rod a201, and a second foot pedal 303 mounted on the end of the second extension rod b302 away from the first extension rod b301.

[0036] In a preferred embodiment, the positioning element for positioning the first extension rod a201 includes: a connecting plate a400 for mounting on a bicycle frame; a sliding sleeve a402, with a rotating connector a404 connecting the sliding sleeve a402 and the connecting plate a400, the sliding sleeve a402 rotating on the connecting plate a400 via the rotating connector a404, and the first extension rod a201 slidably disposed with the sliding sleeve a402; the positioning element for positioning the first extension rod b301 includes: a connecting plate b500 for mounting on a bicycle frame; a sliding sleeve b502, with a rotating connector b504 connecting the sliding sleeve b502 and the connecting plate b500, the sliding sleeve b502 rotating on the connecting plate b500 via the rotating connector b504, and the first extension rod b301 slidably disposed with the sliding sleeve b502.

[0037] Optionally, the sliding sleeve in the positioning component can be round, square, or other shapes, and the sliding opening can be changed according to the direction of the drive component. The connecting plate a400 or the connecting plate b500 can be fixed to the bicycle's rear chain fork, rear upper fork, or components welded between the rear upper fork and rear chain fork.

[0038] Furthermore, the positioning component is not limited to the above method. For example, the slide can be fixed by one or more sets of elastic telescopic components. One end of the elastic telescopic component is connected to the bicycle's rear chain fork, rear upper fork, or a component welded between the rear upper fork and rear chain fork, and the other end is connected to the slide through a rotating unit to achieve the above purpose.

[0039] Alternatively, the connecting plate a400 may have a connecting hole a401, and the connecting plate b500 may have a connecting hole b501.

[0040] Preferably, the first extension rod a201 is provided with a first sliding groove 204, the inner side of the sliding sleeve a402 is provided with a slider a403 that cooperates with the first sliding groove 204, the first extension rod b301 is provided with a second sliding groove 304, and the inner side of the sliding sleeve b502 is provided with a slider b503 that cooperates with the second sliding groove 304.

[0041] Furthermore, the first groove 204 passes through the end of the first extension rod a201, and the end of the first extension rod a201 is detachably connected to the first baffle 205. The second groove 304 passes through the end of the first extension rod b301, and the end of the first extension rod b301 is detachably connected to the second baffle 305.

[0042] In a preferred embodiment, the end of the first crank 104 away from the chainring 100 is connected to a first connecting shaft 200, and the connection between the first extension rod a201 and the second extension rod a202 is rotatably connected to the first connecting shaft 200; the end of the second crank 105 away from the chainring 100 is connected to a second connecting shaft 300, and the connection between the first extension rod b301 and the second extension rod b302 is rotatably connected to the second connecting shaft 300.

[0043] The above are merely preferred embodiments of this utility model, but the scope of protection of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in this utility model, based on the technical solution and inventive concept of this utility model, should be included within the scope of protection of this utility model.

Claims

1. A bicycle power mechanism with an extender crank, comprising: A chainring (100) and a freewheel (101) are provided, wherein a chain (102) connects the chainring (100) and the freewheel (101), and a fixed shaft (103) is connected to the chainring (100). One end of the fixed shaft (103) is connected to a first crank (104), and the other end is connected to a second crank (105). The first crank (104) and the second crank (105) are symmetrically arranged. The characteristic feature is that: Both the first crank (104) and the second crank (105) are connected to a drive unit. One end of the drive unit is connected to the bicycle frame through a positioning member, and the other end is connected to a pedal assembly. The pedal assembly forms a first center (600) in a circular motion, and the connection between the drive member and the first crank (104) and the second crank (105) forms a second center (700) in a circular motion. The first center (600) is located above the second center (700), and the first center (600) is located in front of the second center (700) along the forward direction of the bicycle.

2. Bicycle power mechanism with a grow crank according to claim 1, characterized in that: The driving component includes A first extension rod a (201) is connected to the first crank (104), and a second extension rod a (202) is connected to one end of the first extension rod a (201). The second extension rod a (202) is bent upward at an obtuse angle relative to the first extension rod a (201). A first extension rod b (301) is connected to the second crank (105), and a second extension rod b (302) is connected to one end of the first extension rod b (301). The second extension rod b (302) is bent upward at an obtuse angle relative to the first extension rod b (301). Wherein, the two obtuse angles are the same, and the first extension rod a (201) and the first extension rod b (301) are both connected to the bicycle frame through the positioning member.

3. Bicycle power mechanism with a grow crank according to claim 2, characterized in that: The foot pedal assembly includes a first foot pedal (203) installed on the end of the second extension rod a (202) away from the first extension rod a (201), and a second foot pedal (303) installed on the end of the second extension rod b (302) away from the first extension rod b (301).

4. The bicycle power mechanism with an extending crank according to claim 2, characterized in that: The positioning element for positioning the first extension rod a (201) includes: Connecting plate a (400) is used for mounting on a bicycle frame; A sliding sleeve a (402) is connected to a connecting plate a (400) by a rotating connector a (404). The sliding sleeve a (402) rotates on the connecting plate a (400) via the rotating connector a (404). The first extension rod a (201) is slidably disposed with the sliding sleeve a (402). The positioning element for positioning the first extension rod b (301) includes: Connecting plate b (500) is used for mounting on the bicycle frame; A sliding sleeve b (502) is connected to the connecting plate b (500) by a rotating connector b (504). The sliding sleeve b (502) rotates on the connecting plate b (500) through the rotating connector b (504). The first extension rod b (301) is slidably disposed with the sliding sleeve b (502).

5. A cycle power mechanism with a grow crank as claimed in claim 4, characterized in that: The connecting plate a (400) is provided with a connecting hole a (401), and the connecting plate b (500) is provided with a connecting hole b (501).

6. A cycle power mechanism with a grow crank as claimed in claim 4, characterized in that: The first extension rod a (201) is provided with a first sliding groove (204), and the inner side of the sliding sleeve a (402) is provided with a slider a (403) that cooperates with the first sliding groove (204). The first extension rod b (301) is provided with a second sliding groove (304), and the inner side of the sliding sleeve b (502) is provided with a slider b (503) that cooperates with the second sliding groove (304).

7. A cycle power mechanism with a grow crank as claimed in claim 6, characterized in that: The first groove (204) passes through the end of the first extension rod a (201), and the end of the first extension rod a (201) is detachably connected to a first baffle (205). The second groove (304) passes through the end of the first extension rod b (301), and the end of the first extension rod b (301) is detachably connected to a second baffle (305).

8. The bicycle power mechanism with an extending crank according to claim 2, characterized in that: The first crank (104) is connected to a first connecting shaft (200) at the end away from the chainring (100), and the connection between the first extension rod a (201) and the second extension rod a (202) is rotatably connected to the first connecting shaft (200); The end of the second crank (105) away from the chainring (100) is connected to a second connecting shaft (300), and the connection between the first extension rod b (301) and the second extension rod b (302) is rotatably connected to the second connecting shaft (300).

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