Labor-saving crank of bicycle

Abstract

A bicycle labor-saving crank is characterized in that a base arm is located on the outer side of a large disc, one end of the base arm is combined with the large disc, and the base arm synchronously rotates along with the large disc; the base chain wheel is fixed to the base arm and faces the large disc. The outer chain wheel is rotationally connected to the other end of the base arm through an outer axis; the conveying component is rotationally connected to the base chain wheel and the outer chain wheel; one end of the outer arm is rotationally connected to the outer axis and synchronously rotated with the outer chain wheel, and the other end of the outer arm is rotationally connected with the pedal. The length of the outer arm is additionally increased, so that the length of the arm of force is increased in treading, and the effect of saving labor is achieved.

Description

Technical Field

[0001] The present invention relates to a driving structure of a bicycle, and in particular to a crank assembly structure. Background Art

[0002] Current bicycle drive Fig.10 As shown, the large plate is rotatably connected to the frame through an axis, and a pair of cranks are connected to the axis and the large plate in opposite directions, and the ends of the cranks are connected to rotatable pedals. When pedaling a bicycle, the pedals and cranks are applied by both feet, and the cranks rotate in a circular trajectory in a counterclockwise direction, driving the large plate to rotate under the aforementioned trajectory, and the large plate drives the chain to rotate, and the chain drives the rear sprocket to rotate, and finally drives the rear wheel to rotate to achieve the forward movement of the bicycle.

[0003] When the crank is not wearing special shoes with movable pedals, the crank is basically driven by the downward pedal force when rotating in the above-mentioned circular trajectory. When the pedal is in the upward state, it is impossible to effectively apply force. Therefore, in order to increase the operating efficiency, wearing a pedal structure that can be specifically fixed to the pedal is one of the solutions. However, the general public usually only wears ordinary shoes when riding a bicycle, and will not choose a pedal with an upper clamping structure. Summary of the invention

[0004] The main technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a bicycle labor-saving crank. The outer arm has an additional length dimension, which increases the length of the force arm during pedaling, thereby achieving the effect of labor saving. Moreover, the trajectory of the outer arm is offset outwardly in the direction of travel compared to the trajectory of the base arm, so that the original top dead point position (facing the vertical position and unable to step down) that cannot transmit the pedaling force can be offset forward, so that the force can be transmitted more effectively, ultimately achieving labor saving and a better pedaling trajectory.

[0005] The technical solution adopted by the present invention to solve its technical problem is:

[0006] A labor-saving crank for a bicycle, comprising:

[0007] A base arm is located outside the large disk and one end of the base arm is connected to the large disk. The base arm rotates synchronously with the large disk.

[0008] A base sprocket, which is fixed to the base arm and faces the direction of the large disk;

[0009] An outer sprocket, which is rotatably connected to the other end of the base arm about an outer axis;

[0010] a transmission member rotatably connected to the base sprocket and the outer sprocket;

[0011] and an outer arm, one end of which is rotatably connected to the outer axis and rotated synchronously with the outer sprocket, and the other end of which is rotatably connected to the pedal;

[0012] The outer arm is rotatably connected to the base arm and rotates synchronously with the large plate to form a circular base arm trajectory, while the pedal is rotatably connected to the outer arm and rotates with the base arm to form a circular outer arm trajectory;

[0013] The outer arm trajectory is offset outwardly in the direction of travel relative to the base arm trajectory.

[0014] The aforementioned base arm is roughly the same as the currently known crank length. The outer arm becomes an additional length dimension, which increases the length of the force arm during pedaling, thereby achieving the effect of saving effort. Moreover, the trajectory of the outer arm is offset outwardly in the direction of travel compared to the trajectory of the base arm. The original top dead point position (facing the vertical position and unable to step down) that cannot transmit the pedaling force can be offset forward, thereby enabling the force to be transmitted more effectively, ultimately achieving effort saving and a better pedaling trajectory. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0016] Figure 1 It is a side view of the present invention, with the crank in a forward extending position.

[0017] Figure 2 It is a schematic diagram of the operation of the base arm of the present invention in a downwardly extended position.

[0018] Figure 3 It is a schematic diagram of the operation of the base arm of the present invention in a backward extended position.

[0019] Figure 4 It is a schematic diagram of the operation of the base arm of the present invention in an upwardly extended position.

[0020] Figure 5 yes Figures 1 to 5 Schematic diagram of the operation simulation of the base arm position.

[0021] Figure 6 It is a schematic diagram of the outer arm of the present invention being at an upward tilt angle relative to the base arm.

[0022] Figure 7 yes Figure 6 A partial enlarged schematic diagram.

[0023] Figure 8 It is a schematic diagram of the base arm trajectory and the outer arm trajectory of the present invention.

[0024] Fig. 9 It is a schematic diagram of the simulation of the present invention applied to a labor-saving frame compared with a standard frame.

[0025] Fig.10It is a side view schematic diagram of the crank and the large plate of the bicycle of the prior art. DETAILED DESCRIPTION

[0026] See also Figures 1 to 5 and Figure 8 As shown, the figure discloses a bicycle labor-saving crank 1, comprising:

[0027] A base arm 200, which is located outside the large plate 10 and one end of which is coupled to the large plate 10, and the base arm 200 rotates synchronously with the large plate 10;

[0028] A base sprocket 300, which is fixed to the base arm 200 and faces the direction of the large disk 10;

[0029] An outer sprocket 400 is rotatably connected to the other end of the base arm 200 about an outer axis 410;

[0030] a transmission member 500 rotatably connected to the base sprocket 300 and the outer sprocket 400;

[0031] and an outer arm 600, one end of which is rotatably connected to the outer shaft 410 and rotated synchronously with the outer sprocket 400, and the other end of the outer arm 600 is rotatably connected to the pedal 610;

[0032] The outer arm 600 is rotatably connected to the base arm 200 and rotates synchronously with the large plate 10 to form a circular base arm trajectory T1, and the pedal 610 is rotatably connected to the outer arm 600 and rotates with the base arm 200 to form a circular outer arm trajectory T2; the outer arm trajectory T2 is offset outwardly in the direction of travel relative to the base arm trajectory T1.

[0033] The aforementioned base arm 200 is roughly the same as the currently known crank length dimension (for example, 170mm), and the additional outer arm 600 becomes an additional length dimension (roughly 85mm), which increases the length of the force arm for pedaling (compared to the original crank with a length of only 170mm, the total length of this case reaches 255mm (the total axial length of the base arm and the outer arm), which is equivalent to increasing the original force arm by half. After this conversion, 50% of the force can be saved), and the outer arm trajectory T2 is offset outward from the base arm trajectory T1 toward the direction of travel, so that the original top dead point position (facing the vertical position and unable to step down) that cannot transmit the pedaling force can be offset forward (the forward here refers to the direction of travel of the bicycle, and the right side of the figure is taken as an example), so that the force can be transmitted more effectively, and ultimately labor saving and a better pedaling trajectory are achieved.

[0034] It must be explained that the present invention uses a combination of a base arm 200 and an outer arm 600 to form a crank. In principle, a bicycle uses a pair of cranks to drive the large plate 10 in opposite positions. However, in order to clearly determine the position of components and the operating conditions, the present invention only uses a single crank in the accompanying drawings, and does not show the bicycle labor-saving crank 1 installed on the bicycle frame.

[0035] The axial dimension of the base arm 200 of the present invention is greater than the axial dimension of the outer arm 600. In principle, the base arm 200 is roughly the same size as the conventional crank, and the main difference lies in the added outer arm 600, and the outer arm 600 can continuously change position during the pedaling process, which not only increases the application in the forward direction, but also shortens the unnecessary backward extension of the outer arm 600 in the ineffective area in the rear direction.

[0036] The detailed features of each component and the functions that can be achieved by the combination operation are further described. The bicycle labor-saving crank 1 of the present invention, wherein the transmission component 500 is a chain or a gear. The transmission component 500 of this embodiment is a chain as an example, and the chain rotates between the base sprocket 300 and the outer sprocket 400. The aforementioned gear can be a bevel gear to facilitate reversing and power transmission. The transmission component 500 of the present invention cooperates with the base sprocket 300 and the outer sprocket 400 to effectively control the rotation position of the outer arm 600 relative to the base arm 200, that is, accurately control the outer arm 600 to rotate relative to the base arm 200 to form the aforementioned circular outer arm trajectory T2.

[0037] When the base arm 200 is horizontal and extends in the direction of the bicycle, the outer arm 600 extends in the same direction as the base arm 200. Figure 1 and Figure 6 As shown, at this time, the total length of the base arm 200 and the outer arm 600 of the present invention in a horizontal state is presented, that is, the position where the longest lever arm is exhibited by the present invention.

[0038] In addition to the above-mentioned base arm 200 being horizontal and extending in the direction of travel of the bicycle, and the base arm 200 and the outer arm 600 being both in a horizontal state, there is another embodiment, which can be seen in FIG. Figure 6 , Figure 7 As shown, when the base arm 200 is horizontal and extends in the direction of the bicycle, the axial extension line L1 of the outer arm 600 is arranged at an angle relative to the horizontal extension line L2 of the base arm 200, so that the outer arm 600 is at an upward angle relative to the base arm 200. Through the above configuration, the pedaling action can be performed more efficiently. The aforementioned angle is a 36° configuration type. The aforementioned angle is an 18° configuration type, which is the best angle when the present invention is implemented.

[0039] See also Figure 8 As shown, the base arm track T1 and the outer arm track T2 have the same diameter, and the base arm track T1 and the outer arm track T2 intersect twice. The shortest distance between the outer arm track T2 and the large disk 10 is smaller than the shortest distance between the base arm track T1 and the large disk 10.

[0040] See also Fig. 9As shown, when the bicycle labor-saving crank 1 is applied to the bicycle frame, the bicycle frame (herein referred to as the labor-saving frame 710) can be improved in accordance with the bicycle labor-saving crank 1, that is, the center of the main spindle tube (commonly known as the five-way tube) where the frame is mounted with the crank should be moved back and lowered (herein, the so-called moving back and lowering refers to the improvement of the labor-saving frame 710 relative to the standard frame 720), A in the figure is the center of the mounting plate of the standard frame 720, and B in the figure is the mounting plate of the labor-saving frame 710 10, the length of the outer arm 600 (the length referred to here refers to the distance between the outer arm 600 and the outer axis 410 and the pedal 610 respectively connected by rotation) is Y, the base arm 200 is horizontal and extends in the direction of travel of the bicycle, and the elevation angle of the outer arm 600 relative to the base arm 200 is θ. Based on the above requirements, the retreat value of the center position of the main spindle tube of the labor-saving frame 710 is B=A-Ycosθ, and the descending value of the center position of the main spindle tube of the labor-saving frame 710 is B=A-Ysinθ.

[0041] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A labor-saving bicycle crank, characterized in that: include: A base arm is located outside the large disk and one end of the base arm is connected to the large disk. The base arm rotates synchronously with the large disk. A base sprocket, which is fixed to the base arm and faces the direction of the large disk; An outer sprocket, which is rotatably connected to the other end of the base arm about an outer axis; a transmission member rotatably connected to the base sprocket and the outer sprocket; and an outer arm, one end of which is rotatably connected to the outer axis and rotated synchronously with the outer sprocket, and the other end of which is rotatably connected to the pedal; The outer arm rotates at the point where it connects to the base arm and rotates synchronously with the large plate to form a circular base arm trajectory, while the pedal rotates at the point where it connects to the outer arm and rotates with the base arm to form a circular outer arm trajectory; the outer arm trajectory is offset outwardly in the direction of travel relative to the base arm trajectory.

2. The bicycle labor-saving crank according to claim 1, characterized in that: The transmission member is a chain or a gear.

3. The bicycle labor-saving crank according to claim 1, characterized in that: When the base arm is horizontal and extends toward the traveling direction of the bicycle, the outer arm extends in the same direction as the base arm.

4. The bicycle labor-saving crank according to claim 1, characterized in that: When the base arm is horizontal and extends toward the traveling direction of the bicycle, the axial extension line of the outer arm is arranged at an angle relative to the horizontal extension line of the base arm, so that the outer arm is at an upward angle relative to the base arm.

5. The bicycle labor-saving crank according to claim 4, characterized in that: The aforementioned angle is 36°.

6. The bicycle labor-saving crank according to claim 4, characterized in that: The aforementioned angle is 18°.

7. The bicycle labor-saving crank according to claim 1, characterized in that: The base arm trajectory and the outer arm trajectory are both of the same diameter, and the base arm trajectory intersects the outer arm trajectory twice.

8. The bicycle labor-saving crank according to claim 1, characterized in that: The shortest distance between the outer arm trajectory and the large disk is smaller than the shortest distance between the base arm trajectory and the large disk.

9. The bicycle labor-saving crank according to claim 1, characterized in that: The axial dimension of the base arm is greater than the axial dimension of the outer arm.

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