Rear double-wheel driving type double-lever prying labor-saving tricycle and method

Abstract

The invention discloses a rear double-wheel driving type double-lever prying labor-saving tricycle and a method, and relates to a rickshaw transmission structure. A rear double-wheel driving type double-lever prying labor-saving tricycle comprises a tricycle frame, a front fork, a front wheel, a tricycle hopper, rear wheels and a transmission system. The transmission system comprises two sets of double-lever prying transmission mechanisms; the double-lever prying transmission mechanism comprises a base plate, a crank, a lever A, a rocker A, a lever B and a rocker B; the base plates of the two sets of double-lever prying transmission mechanisms are fixedly connected to the outer sides of the two horizontal rods A respectively, and the two sets of double-lever prying transmission mechanisms share one rotating shaft; and the rotating shaft is in power association with the rear wheel shaft, so that the rotating shaft drives the rear wheel shaft and the two rear wheels to rotate while rotating. The transmission mechanism has the advantages that through the design of the force arm proportion of the lever A and the lever B, two-stage force amplification is achieved, and the gear ratio limit of traditional chain transmission is far exceeded. Therefore, more labor is saved when the rear double-wheel drive type tricycle is driven, especially when the tricycle is started or climbs a slope.

Description

Technical Field

[0001] The invention relates to a rickshaw transmission structure, in particular to a rear double-wheel drive double-lever prying labor-saving tricycle and a method thereof. Background Art

[0002] The transmission structure of existing human-powered tricycles mostly uses a sprocket and chain transmission pair. In other words, the human foot moves in circles on two pedals, which rotates the driving sprocket, which in turn drives the driven sprocket through the chain, thereby driving the tricycle forward. Although existing human-powered tricycles can achieve labor-saving effects by shifting gears (essentially changing the gear ratio between the chainring and flywheel), this labor-saving effect is limited by various factors and has an upper limit (the gear ratio limit is approximately 0.43, meaning that for every pedaling rotation, the rear wheel only rotates 0.43 times).

[0003] The limiting factors are mainly reflected in the following aspects: Limitation of the lever arm ratio: The radius of the circle drawn with the center point of the flywheel as the center is equivalent to the power arm, and the radius of the drive wheel (usually the rear wheel) is equivalent to the resistance arm. Due to the limitations of the flywheel size and installation position, as well as the drive wheel size and vehicle structure, the length of the power arm will not be greater than the resistance arm, and the effort-saving effect is relatively limited.

[0004] Limitations of mechanical design: A flywheel that is too large requires a longer rear derailleur and frame space, which can easily exceed the conventional design range; a chainring with too small a number of teeth can lead to poor engagement between the chain and the chainring, which can easily cause the chain to come off or wear out; under extreme gear ratios, the chain's inclination angle is too large (for example, a small chainring + a large flywheel), resulting in increased friction loss and reduced transmission efficiency.

[0005] Ergonomic limitations: If the gear ratio is too small (for example, <0.43), the rider will only move forward a short distance after pedaling one circle. The rider will need to pedal at an extremely high frequency to maintain a certain speed, which is far beyond the human body's comfort range and can easily lead to muscle fatigue or knee injuries, which is counterproductive.

[0006] In summary, it is very necessary to design a new transmission structure for human-powered tricycles so that they can achieve better labor-saving effects and have good riding comfort. Summary of the Invention

[0007] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide a rear two-wheel drive double-lever prying labor-saving tricycle and method. It improves the transmission mechanism of the traditional human-powered tricycle and adopts a double-lever prying transmission mechanism to replace the sprocket and chain transmission mechanism of the traditional human-powered tricycle, which can achieve better labor-saving effect and at the same time has good riding comfort.

[0008] The technical solution of the present invention is: a rear dual-wheel drive double-lever prying labor-saving tricycle, comprising a frame, a front fork, a front wheel, a front wheel axle, a bucket, a rear wheel axle, a rear wheel and a transmission system; The middle part of the frame is provided with a vertically inclined main rod, the upper end of the main rod is provided with a seat cushion, the front end of the frame is provided with a front fork frame, the front fork frame is provided with a front fork mounting hole, the rear end of the frame is provided with a U-shaped frame, and the U-shaped frame is provided with a first U-shaped section and a second U-shaped section connected in sequence from the closed end to the open end, the width of the second U-shaped section is greater than the width of the first U-shaped section, the first U-shaped section includes two parallel horizontal rods A, the second U-shaped section includes two parallel horizontal rods B, the closed end of the U-shaped frame is fixedly connected to the lower end of the main rod, and the open end of the U-shaped frame extends toward the rear end of the frame; the front fork is rotatably mounted in the front fork mounting hole; the front wheel is rotatably mounted on the lower end of the front fork through the front wheel axle; the bucket is fixedly mounted on the upper end of the second U-shaped section and is located above the middle of the rear end of the frame; the rear wheel axle is rotatably mounted on the two horizontal rods B, and the two ends of the rear wheel axle extend outwards of the second U-shaped section respectively; the two rear wheels are respectively mounted at both ends of the rear wheel axle, and are both located outside the second U-shaped section; The transmission system includes two sets of double-lever prying transmission mechanisms; the double-lever prying transmission mechanism includes a base plate, a crank, a lever A, a rocker A, a lever B and a rocker B; the front end of the crank is rotatably mounted on the base plate through a rotating shaft, and the rear end of the crank is hinged to the front end of the lever A; a hinge point A is provided between the front and rear ends of lever A, and the rear end of lever A is hinged to the front end of lever B; the front end of rocker A is hinged to the base plate, and the rear end of rocker A is hinged to the hinge point A of lever A; a hinge point B is provided between the front and rear ends of lever B, and the rear end of lever B is a free end; the front end of rocker B Hinge-connected to the base plate, the rear end of the rocker B is hinged to the hinge point B of the lever B; when the crank rotates in a circle, the lever A swings up and down around the hinge point A, and the lever B swings up and down around the hinge point B; the base plates of the two sets of double-lever prying transmission mechanisms are respectively fixedly connected to the outer sides of the two horizontal bars A, and the two sets of double-lever prying transmission mechanisms share a rotating shaft; the front ends of the cranks of the two sets of double-lever prying transmission mechanisms are respectively connected to the two ends of the same rotating shaft; the rotating shaft is dynamically connected to the rear wheel axle, so that the rotation of the rotating shaft drives the rear wheel axle and the two rear wheels to rotate at the same time.

[0009] A further technical solution of the present invention is: the rotating shaft and the rear wheel shaft are dynamically connected through a sprocket chain pair; the sprocket chain pair includes a driving sprocket, a driven sprocket and a chain; the driving sprocket is fixedly installed in the middle of the rotating shaft, the driven sprocket is fixedly installed in the middle of the rear wheel shaft, and the chain is wound between the driving sprocket and the driven sprocket.

[0010] A further technical solution of the present invention is: the transmission system also includes two sets of pedal assemblies; the pedal assembly includes a pedal shaft and a pedal fixedly mounted on the pedal shaft, one end of the pedal shaft extends outside the pedal to form a mounting end; the two sets of pedal assemblies are respectively rotatably mounted on the free ends of levers B of the two sets of double-lever prying transmission mechanisms through the mounting ends of the pedal shaft, and are arranged perpendicular to the lever B.

[0011] A further technical solution of the present invention is that when the free end of the lever B moves from the uppermost end to the lowermost end and then to the uppermost end of the swing stroke, the crank rotates 360°.

[0012] A further technical solution of the present invention is: the rod section of lever A between the front end and the hinge point A is defined as the first resistance arm, the rod section of lever A between the rear end and the hinge point A is defined as the first power arm, the rod section of lever B between the front end and the hinge point B is defined as the second resistance arm, and the rod section of lever B between the rear end and the hinge point B is defined as the second power arm; the length ratio of the first resistance arm to the first power arm is 1:x, and the value range of x is 1.5 to 2.5; the length ratio of the second resistance arm to the second power arm is 1:y, and the value range of y is 2 to 10.

[0013] A further technical solution of the present invention is: the value of x is 2, and the value of y is 4.

[0014] The technical solution of the present invention is: a tricycle power transmission method based on the above-mentioned rear two-wheel drive type double-lever prying labor-saving tricycle; Before executing the method, define the following concepts: Ⅰ. The two sets of double-lever prying transmission mechanisms in the rear two-wheel drive double-lever prying labor-saving tricycle are named as the left mechanism and the right mechanism respectively; II. In a double-lever prying transmission mechanism, the free end of lever B swings from the uppermost end to the lowermost end and then from the lowermost end to the uppermost end, completing a motion cycle. A motion cycle consists of a first half-cycle and a second half-cycle. The first half of the motion cycle is completed when the free end of lever B swings from the uppermost end to the lowermost end, and the second half of the motion cycle is completed when the free end of lever B swings from the lowermost end to the uppermost end. Here’s how: A. Left down, right up: When the free end of lever B of the left mechanism swings downward, the left mechanism is in the first half of the motion cycle. Actively exerting force on the pedal corresponding to the left mechanism drives the free end of lever B of the right mechanism to swing upward passively. At this time, the right mechanism is in the second half of the motion cycle. B. Right down, left up: When the free end of lever B5 of the right mechanism swings downward, the right mechanism is in the first half of the motion cycle. Active force is exerted on the pedal 76 corresponding to the right mechanism, thereby driving the free end of lever B5 of the left mechanism to swing upward passively. At this time, the left mechanism is in the second half of the motion cycle. C. Repeat this process by alternately pedaling on the two pedals, driving the free ends of the levers B5 of the two sets of double-lever prying transmission mechanisms to swing up and down alternately, thereby driving the rotating shaft to rotate continuously in the same direction. The rotating shaft drives the rear wheel shaft and rear wheel to rotate continuously in the same direction through the driving sprocket, chain and driven sprocket, thus realizing the riding of the tricycle; Steps A and B in the method are performed simultaneously.

[0015] A further technical solution of the present invention is: in step A of the above method, the power transmission path includes three consecutive paths: I. Left Mechanism: Stepping on the pedal corresponding to the left mechanism drives lever B in the left mechanism to rotate about hinge point B, causing the free end of lever B to descend and the front end of lever B to rise. Lever B pulls lever A to rotate about hinge point A, causing the front end of lever A to descend and the rear end of lever A to rise. Rockers A and B swing adaptively, and the crank rotates 180° clockwise. II. Rotating shaft: The rotating shaft shared by both mechanisms is driven by the crank in the left mechanism and rotates 180°; III. Right-side mechanism: The rotation of the shaft drives crank 2 in the right-side mechanism to rotate 180°. The crank pulls lever A to rotate about hinge point A, causing the front end of lever A to descend and the rear end of lever A to ascend. Lever A pulls lever B to rotate hinge point B, causing the free end of lever B to ascend and the front end of lever B to descend. At this point, the movement process of "left down and right up" is realized.

[0016] A further technical solution of the present invention is: in step B of the above method, the power transmission path includes three consecutive paths; I. Right Mechanism: Stepping on the pedal corresponding to the right mechanism drives lever B in the right mechanism to rotate about hinge point B, causing the free end of lever B to descend and the front end of lever B to rise. Lever B pulls lever A to rotate about hinge point A, causing the front end of lever A to descend and the rear end of lever A to rise. Rockers A and B swing adaptively, and the crank rotates 180° clockwise. II. Rotating shaft: The rotating shaft shared by both mechanisms is driven by the crank in the right mechanism and rotates 180°; III. Left-side mechanism: The rotation of the shaft drives the crank in the left-side mechanism to rotate 180°. The crank pulls lever A to rotate about hinge point A, causing the front end of lever A to descend and the rear end of lever A to ascend. Lever A pulls lever B to rotate hinge point B, causing the free end of lever B to ascend and the front end of lever B to descend. At this point, the movement process of "lower right and upper left" is realized.

[0017] Compared with the prior art, the present invention has the following advantages: 1. Significant two-stage effort-saving effect: By designing the lever arm ratios of levers A and B, a two-stage force amplification is achieved. Taking the example of lever A with a 1:2 lever arm ratio and lever B with a 1:4 lever arm ratio in Example 1 as an example, the total effort-saving ratio reaches 1:8, far exceeding the gear ratio limit of a traditional chain drive (0.43). This makes driving a rear-wheel drive tricycle more effortless, especially when starting or climbing a slope.

[0018] 2. High Riding Comfort: Two dual-lever prying drive mechanisms are symmetrically arranged on either side of the U-shaped frame. Riders propel the tricycle by alternately pedaling downwards. Compared to the circular pedaling of traditional tricycles, this linear up-and-down motion better aligns with the body's natural force generation, reducing the risk of muscle fatigue and knee injuries, and improving comfort during extended rides.

[0019] 3. Stable structure and efficient drive: Two dual-lever prying drive mechanisms are symmetrically arranged on either side of the U-shaped frame, sharing a common drive shaft to directly drive the single rear wheel. The compact structure offers excellent rigidity and direct and efficient power transmission. This makes it particularly suitable for rear-wheel drive tricycles requiring a certain load capacity, such as freight tricycles.

[0020] The present invention is further described below with reference to the figures and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a structural diagram of the transmission system under the first perspective; Figure 3 It is a structural diagram of the transmission system under the second perspective; Figure 4 This is a top-down structural diagram of the U-shaped skeleton; Figure 5 This is the simplified motion trajectory diagram of the double-lever prying transmission mechanism structure; Figure 6 This is the state diagram of the double-lever prying transmission mechanism at the beginning of the first half of the motion cycle; Figure 7 This is the first state diagram of the double-lever prying transmission mechanism in the first half of the motion cycle; Figure 8 This is the second state diagram of the double-lever prying transmission mechanism in the first half of the motion cycle; Figure 9 This is the state diagram of the double-lever prying transmission mechanism at the beginning of the second half of the motion cycle; Figure 10 This is the first state diagram of the double-lever prying transmission mechanism in the second half of the motion cycle; Figure 11 This is the second state diagram of the double-lever prying transmission mechanism in the second half of the motion cycle.

[0022] Special Notes: Figure 1 The red line in the figure is the double-lever prying transmission mechanism. Figure 1 The blue line in the figure is the sprocket chain pair located between the rotating shaft and the rear wheel axle.

[0023] Special Notes: Figure 5 Each line segment in the figure represents a rod. All rods in one color represent a motion state of the transmission mechanism. Green arcs or circles represent the motion trajectories of different rods. Multiple colors on a line indicate that the rod is in this position in multiple states of the transmission mechanism.

[0024] Legend: Base plate 1; crank 2; rotating shaft 21; lever A3; hinge point A31; rocker A4; lever B5; hinge point B51; rocker B6; frame 71; main rod 711; front fork skeleton 712; U-shaped skeleton 713; first U-shaped segment 7131; horizontal rod A71311; second U-shaped segment 7132; horizontal rod B71321; front fork 72; front wheel 73; front wheel axle 74; cart 75; rear wheel axle 76; rear wheel 77; driving sprocket 81; driven sprocket 82; chain 83; pedal 91. DETAILED DESCRIPTION Example 1

[0025] like Figure 1-11 As shown, the rear two-wheel drive double-lever prying labor-saving tricycle includes a frame 71, a front fork 72, a front wheel 73, a front wheel axle 74, a vehicle box 75, a rear wheel axle 76, a rear wheel 77 and a transmission system.

[0026] The frame 71 is a unitary rigid member. A vertically inclined main rod 711 is provided in the middle of the frame 71. A seat cushion is provided at the upper end of the main rod 711. A front fork frame 712 is provided at the front end of the frame 71, with a front fork mounting hole provided therein. A U-shaped frame 713 is provided at the rear end of the frame 71. The U-shaped frame 713 comprises a first U-shaped section 7131 and a second U-shaped section 7132, which are connected in sequence from the closed end to the open end. The width W2 of the second U-shaped section 7132 is greater than the width W1 of the first U-shaped section 7131. The first U-shaped section 7131 includes two parallel horizontal rods A71311, and the second U-shaped section 7132 includes two parallel horizontal rods B71321. The closed end of the U-shaped frame 713 is fixedly connected to the lower end of the main rod 711, and the open end of the U-shaped frame 713 extends toward the rear end of the frame 71. The front fork 72 is rotatably mounted in the front fork mounting hole. The front wheel 73 is rotatably mounted to the lower end of the front fork 72 via a front wheel axle 74. The truck bed 75 is fixedly mounted to the upper end of the second U-shaped section 7132 and positioned above the center of the rear end of the vehicle frame 71. The rear wheel axle 76 is rotatably mounted on two horizontal rods B71321, with both ends of the rear wheel axle 76 extending outside the second U-shaped section 7132. Two rear wheels 77 are mounted on both ends of the rear wheel axle 76 and are both located outside the second U-shaped section 7132. The two rear wheels 77 rotate under the drive system.

[0027] The transmission system includes two dual-lever prying transmission mechanisms. These mechanisms comprise a base plate 1, a crank 2, a lever A3, a rocker A4, a lever B5, and a rocker B6. The front end of crank 2 is rotatably mounted on base plate 1 via a rotating shaft 21 (the front end of crank 2 is fixedly connected to rotating shaft 21). The rear end of crank 2 is hinged to the front end of lever A3. Lever A3 has a hinge point A31 between its front and rear ends, and its rear end is hinged to the front end of lever B5. The front end of rocker A4 is hinged to base plate 1, and its rear end is hinged to hinge point A31 of lever A3. Lever B5 has a hinge point B51 between its front and rear ends, with its rear end being free. The front end of rocker B6 is hinged to base plate 1, and its rear end is hinged to hinge point B of lever B5. As crank 2 rotates in a circular motion, lever A3 swings up and down around hinge point A31, and lever B5 swings up and down around hinge point B51.

[0028] The base plates 1 of the two dual-lever prying transmission mechanisms are fixedly connected to the outsides of the two horizontal rods A71311, and the two dual-lever prying transmission mechanisms share a common rotating shaft 21. "Shared" means that the front ends of the cranks 2 of the two dual-lever prying transmission mechanisms are connected to the two ends of the same rotating shaft 21.

[0029] The rotating shaft 21 and the rear wheel axle 76 are dynamically connected via a sprocket chain pair, so that rotation of the rotating shaft 21 simultaneously drives rotation of the rear wheel axle 76 and the two rear wheels 77. The sprocket chain pair includes a driving sprocket 81, a driven sprocket 82, and a chain 83. The driving sprocket 81 is fixedly mounted in the middle of the rotating shaft 21, the driven sprocket 82 is fixedly mounted in the middle of the rear wheel axle 76, and the chain 83 is wound between the driving sprocket 81 and the driven sprocket 82.

[0030] Preferably, the transmission system further includes two pedal assemblies. The pedal assemblies include a pedal shaft and a pedal 91 fixedly mounted on the shaft. One end of the pedal shaft extends outside of the pedal 91 to form a mounting end. The two pedal assemblies are rotatably mounted to the free ends of levers B5 of the two dual-lever prying transmission mechanisms via the mounting ends of the pedal shafts, and are arranged perpendicular to the levers B5.

[0031] Preferably, when the free end of the lever B5 moves from the uppermost end to the lowermost end and then to the uppermost end of the swing stroke, the crank 2 rotates 360°.

[0032] Preferably, the section of lever A3 between the front end and hinge point A31 is defined as the first resistance arm, the section of lever A3 between the rear end and hinge point A31 is defined as the first power arm, the section of lever B5 between the front end and hinge point B51 is defined as the second resistance arm, and the section of lever B5 between the rear end and hinge point B51 is defined as the second power arm. The length ratio of the first resistance arm to the first power arm is 1:x, where x is 2; the length ratio of the second resistance arm to the second power arm is 1:y, where y is 4.

[0033] The working principle of the double-lever prying transmission mechanism in the present invention is as follows: The free end of lever B5 swings from the uppermost end (upper extreme point) to the lowermost end (lower extreme point) and then from the lowermost end to the uppermost end, completing one movement cycle of the double-lever prying transmission mechanism. A movement cycle consists of a first half movement cycle and a second half movement cycle. The first half movement cycle is completed when the free end of lever B5 swings from the uppermost end to the lowermost end, and the second half movement cycle is completed when the free end of lever B5 swings from the lowermost end to the uppermost end.

[0034] During the first half of the motion cycle, an external driving force (i.e., downward pressure) is applied to the free end of lever B5. Under this external driving force, lever B5 rotates about hinge point B51, causing the free end of lever B5 to descend and the front end of lever B5 to ascend. Lever B5 pulls lever A3 to rotate about hinge point A31, causing the front end of lever A3 to descend and the rear end of lever A3 to ascend. Rockers A4 and B6 oscillate adaptively, and crank 2 rotates approximately 180° clockwise (the shaft 21 fixed to the front end of crank 2 also rotates synchronously by the same angle).

[0035] During the second half of the motion cycle, an external driving force (i.e., a clockwise torque) must be applied to shaft 21. Under this external driving force, crank 2 rotates approximately 180° clockwise (shaft 21, which is fixedly connected to the front end of crank 2, also rotates synchronously by the same angle). Crank 2 pulls lever A3 around hinge point A31, causing the front end of lever A3 to descend and the rear end of lever A3 to ascend. Lever A3 pulls lever B5 around hinge point B51, causing the free end of lever B5 to ascend and the front end of lever B5 to descend.

[0036] The labor-saving effect of the double-lever prying transmission mechanism of the present invention is described as follows: During the first half of the motion cycle, levers B5 and A3 in the dual-lever prying transmission mechanism can achieve first- and second-level effort-saving effects, respectively. As described above, the rod sections of lever B5 on either side of hinge point B51 are the second power arm (the rod section between the rear end of lever B5 and hinge point B51) and the second resistance arm (the rod section between the front end of lever B5 and hinge point B51). The rod sections of lever A3 on either side of hinge point A31 are the first power arm (the rod section between the rear end of lever A3 and hinge point A31) and the first resistance arm (the rod section between the front end of lever A3 and hinge point A31). During the first half of the motion cycle, the external driving force is applied to the second power arm (the free end of lever B5). Because the second power arm is longer than the second resistance arm, the first-level effort-saving effect is achieved through the principle of leverage. Because the second resistance arm is hinged to the first power arm and the first power arm is longer than the first resistance arm, the second-level effort-saving effect is achieved through the principle of leverage, thereby achieving a two-stage multiplied effort-saving effect.

[0037] The working principle of the present invention is as follows: A tricycle power transmission method is based on the above-mentioned rear two-wheel drive type double-lever prying and labor-saving tricycle.

[0038] Before executing the method, define the following concepts: Ⅰ. The two sets of double-lever prying transmission mechanisms in the rear two-wheel drive double-lever prying labor-saving tricycle are named as the left mechanism and the right mechanism respectively; II. In the double-lever prying transmission mechanism, the free end of lever B5 swings from the uppermost end to the lowermost end and then from the lowermost end to the uppermost end, completing a motion cycle. A motion cycle includes a first half motion cycle and a second half motion cycle. The free end of lever B5 swings from the uppermost end to the lowermost end to complete the first half motion cycle, and the free end of lever B5 swings from the lowermost end to the uppermost end to complete the second half motion cycle.

[0039] Here’s how: A. When the free end of the lever B5 of the left mechanism swings downward, the left mechanism is in the first half of the motion cycle. Active force is applied to step on the pedal 76 corresponding to the left mechanism, thereby driving the free end of the lever B5 of the right mechanism to swing upward passively. At this time, the right mechanism is in the second half of the motion cycle.

[0040] B. When the free end of the lever B5 of the right mechanism swings downward, the right mechanism is in the first half of the motion cycle. Active force is exerted on the pedal 76 corresponding to the right mechanism, thereby driving the free end of the lever B5 of the left mechanism to passively swing upward. At this time, the left mechanism is in the second half of the motion cycle.

[0041] C. Repeat this process by alternately pedaling on the two pedals 76, thereby driving the free ends of the levers B5 of the two sets of double-lever prying transmission mechanisms to swing up and down alternately, thereby driving the rotating shaft 21 to rotate continuously in the same direction. The rotating shaft 21 drives the rear wheel shaft 76 and the rear wheel 77 to rotate continuously in the same direction through the driving sprocket 81, the chain 83 and the driven sprocket 82, thereby realizing the riding of the tricycle.

[0042] In step A of the above method, the power transmission path includes three consecutive paths: I. Left Mechanism: Stepping on pedal 76 corresponding to the left mechanism drives lever B5 in the left mechanism to rotate about hinge point B51, causing the free end of lever B5 to descend and the front end of lever B5 to ascend. Lever B5 pulls lever A3 to rotate about hinge point A31, causing the front end of lever A3 to descend and the rear end of lever A3 to ascend. Rockers A4 and B6 swing adaptively, causing crank 2 to rotate 180° clockwise. Ⅱ shaft: The shaft 21 shared by the two mechanisms is driven by the crank 2 in the left mechanism and rotates 180 °; III. Right-side mechanism: The rotation of shaft 21 drives crank 2 in the right-side mechanism to rotate 180°. Crank 2 pulls lever A3 to rotate around hinge point A31, causing the front end of lever A3 to descend and the rear end of lever A3 to ascend. Lever A3 pulls lever B5 to rotate around hinge point B51, causing the free end of lever B5 to ascend and the front end of lever B5 to descend.

[0043] At this point, the movement process of "left down and right up" is realized.

[0044] In sub-step B of the above method, the power transmission path includes three consecutive paths; I. Right Mechanism: Stepping on pedal 76 corresponding to the right mechanism drives lever B5 in the right mechanism to rotate about hinge point B51, causing the free end of lever B5 to descend and the front end of lever B5 to ascend. Lever B5 pulls lever A3 to rotate about hinge point A31, causing the front end of lever A3 to descend and the rear end of lever A3 to ascend. Rockers A4 and B6 swing adaptively, causing crank 2 to rotate 180° clockwise. Ⅱ shaft: the two sets of mechanisms share the shaft 21 is driven by the crank 2 in the right mechanism and rotates 180 °; III. Left-side mechanism: The rotation of shaft 21 drives crank 2 in the left-side mechanism to rotate 180°. Crank 2 pulls lever A3 to rotate around hinge point A31, causing the front end of lever A3 to descend and the rear end of lever A3 to ascend. Lever A3 pulls lever B5 to rotate around hinge point B51, causing the free end of lever B5 to ascend and the front end of lever B5 to descend.

[0045] At this point, the movement process of "lower right and upper left" is realized.

Claims

1. The rear two-wheel drive double-lever prying labor-saving tricycle is characterized by: Includes frame, front fork, front wheel, front axle, truck bed, rear axle, rear wheel and transmission system; The middle part of the frame is provided with a vertically inclined main rod, the upper end of the main rod is provided with a seat cushion, the front end of the frame is provided with a front fork frame, the front fork frame is provided with a front fork mounting hole, the rear end of the frame is provided with a U-shaped frame, and the U-shaped frame is provided with a first U-shaped section and a second U-shaped section connected in sequence from the closed end to the open end, the width of the second U-shaped section is greater than the width of the first U-shaped section, the first U-shaped section includes two parallel horizontal rods A, the second U-shaped section includes two parallel horizontal rods B, the closed end of the U-shaped frame is fixedly connected to the lower end of the main rod, and the open end of the U-shaped frame extends toward the rear end of the frame; the front fork is rotatably mounted in the front fork mounting hole; the front wheel is rotatably mounted on the lower end of the front fork through the front wheel axle; the bucket is fixedly mounted on the upper end of the second U-shaped section and is located above the middle of the rear end of the frame; the rear wheel axle is rotatably mounted on the two horizontal rods B, and the two ends of the rear wheel axle extend outwards of the second U-shaped section respectively; the two rear wheels are respectively mounted at both ends of the rear wheel axle, and are both located outside the second U-shaped section; The transmission system includes two sets of double-lever prying transmission mechanisms; the double-lever prying transmission mechanism includes a base plate, a crank, a lever A, a rocker A, a lever B and a rocker B; the front end of the crank is rotatably mounted on the base plate through a rotating shaft, and the rear end of the crank is hinged to the front end of the lever A; a hinge point A is provided between the front and rear ends of lever A, and the rear end of lever A is hinged to the front end of lever B; the front end of rocker A is hinged to the base plate, and the rear end of rocker A is hinged to the hinge point A of lever A; a hinge point B is provided between the front and rear ends of lever B, and the rear end of lever B is a free end; the front end of rocker B Hinge-connected to the base plate, the rear end of the rocker B is hinged to the hinge point B of the lever B; when the crank rotates in a circle, the lever A swings up and down around the hinge point A, and the lever B swings up and down around the hinge point B; the base plates of the two sets of double-lever prying transmission mechanisms are respectively fixedly connected to the outer sides of the two horizontal bars A, and the two sets of double-lever prying transmission mechanisms share a rotating shaft; the front ends of the cranks of the two sets of double-lever prying transmission mechanisms are respectively connected to the two ends of the same rotating shaft; the rotating shaft is dynamically connected to the rear wheel axle, so that the rotation of the rotating shaft drives the rear wheel axle and the two rear wheels to rotate at the same time.

2. The rear two-wheel drive double-lever prying labor-saving tricycle according to claim 1, characterized in that: The rotating shaft and the rear wheel shaft are dynamically connected through a sprocket chain pair; the sprocket chain pair includes a driving sprocket, a driven sprocket and a chain; the driving sprocket is fixedly installed in the middle of the rotating shaft, the driven sprocket is fixedly installed in the middle of the rear wheel shaft, and the chain is wound between the driving sprocket and the driven sprocket.

3. The rear two-wheel drive double-lever prying labor-saving tricycle according to claim 2, characterized in that: The transmission system also includes two sets of pedal assemblies; the pedal assembly includes a pedal shaft and a pedal fixedly mounted on the pedal shaft, one end of the pedal shaft extends outside the pedal to form a mounting end; The two sets of pedal assemblies are respectively rotatably mounted on the free ends of the levers B of the two sets of double-lever prying transmission mechanisms through the mounting ends of the pedal shafts, and are arranged perpendicular to the levers B.

4. The rear two-wheel drive double-lever prying labor-saving tricycle according to claim 3, characterized in that: When the free end of lever B moves from the uppermost end to the lowermost end and then to the uppermost end of the swing stroke, the crank rotates 360°.

5. The rear two-wheel drive double-lever prying labor-saving tricycle according to claim 4, characterized in that: The rod section of lever A between the front end and the hinge point A is defined as the first resistance arm, the rod section of lever A between the rear end and the hinge point A is defined as the first power arm, the rod section of lever B between the front end and the hinge point B is defined as the second resistance arm, and the rod section of lever B between the rear end and the hinge point B is defined as the second power arm; the length ratio of the first resistance arm to the first power arm is 1:x, and the value range of x is 1.5 to 2.5; the length ratio of the second resistance arm to the second power arm is 1:y, and the value range of y is 2 to 10.

6. The rear two-wheel drive double-lever prying labor-saving tricycle according to claim 5, characterized in that: The value of x is 2 and the value of y is 4.

7. A tricycle power transmission method based on the rear two-wheel drive double-lever prying labor-saving tricycle according to claim 5 or 6; Its characteristics are: Before executing the method, define the following concepts: Ⅰ. The two sets of double-lever prying transmission mechanisms in the rear two-wheel drive double-lever prying labor-saving tricycle are named as the left mechanism and the right mechanism respectively; II. In a double-lever prying transmission mechanism, the free end of lever B swings from the uppermost end to the lowermost end and then from the lowermost end to the uppermost end, completing a motion cycle. A motion cycle consists of a first half-cycle and a second half-cycle. The first half of the motion cycle is completed when the free end of lever B swings from the uppermost end to the lowermost end, and the second half of the motion cycle is completed when the free end of lever B swings from the lowermost end to the uppermost end. Here’s how: A. Left down, right up: When the free end of lever B of the left mechanism swings downward, the left mechanism is in the first half of the motion cycle. Actively exerting force on the pedal corresponding to the left mechanism drives the free end of lever B of the right mechanism to swing upward passively. At this time, the right mechanism is in the second half of the motion cycle. B. Right down, left up: When the free end of lever B5 of the right mechanism swings downward, the right mechanism is in the first half of the motion cycle. Active force is exerted on the pedal 76 corresponding to the right mechanism, thereby driving the free end of lever B5 of the left mechanism to swing upward passively. At this time, the left mechanism is in the second half of the motion cycle. C. Repeat this process by alternately pedaling on the two pedals, driving the free ends of the levers B5 of the two sets of double-lever prying transmission mechanisms to swing up and down alternately, thereby driving the rotating shaft to rotate continuously in the same direction. The rotating shaft drives the rear wheel shaft and rear wheel to rotate continuously in the same direction through the driving sprocket, chain and driven sprocket, thus realizing the riding of the tricycle; Steps A and B in the method are performed simultaneously.

8. The tricycle power transmission method according to claim 7, wherein: In step A of the above method, the power transmission path includes three consecutive paths: I. Left Mechanism: Stepping on the pedal corresponding to the left mechanism drives lever B in the left mechanism to rotate about hinge point B, causing the free end of lever B to descend and the front end of lever B to rise. Lever B pulls lever A to rotate about hinge point A, causing the front end of lever A to descend and the rear end of lever A to rise. Rockers A and B swing adaptively, and the crank rotates 180° clockwise. II. Rotating shaft: The rotating shaft shared by both mechanisms is driven by the crank in the left mechanism and rotates 180°; III. Right-side mechanism: The rotation of the shaft drives crank 2 in the right-side mechanism to rotate 180°. The crank pulls lever A to rotate about hinge point A, causing the front end of lever A to descend and the rear end of lever A to ascend. Lever A pulls lever B to rotate hinge point B, causing the free end of lever B to ascend and the front end of lever B to descend. At this point, the movement process of "left down and right up" is realized.

9. The tricycle power transmission method according to claim 8, wherein: In sub-step B of the above method, the power transmission path includes three consecutive paths; I. Right Mechanism: Stepping on the pedal corresponding to the right mechanism drives lever B in the right mechanism to rotate about hinge point B, causing the free end of lever B to descend and the front end of lever B to rise. Lever B pulls lever A to rotate about hinge point A, causing the front end of lever A to descend and the rear end of lever A to rise. Rockers A and B swing adaptively, and the crank rotates 180° clockwise. II. Rotating shaft: The rotating shaft shared by both mechanisms is driven by the crank in the right mechanism and rotates 180°; III. Left-side mechanism: The rotation of the shaft drives the crank in the left-side mechanism to rotate 180°. The crank pulls lever A to rotate about hinge point A, causing the front end of lever A to descend and the rear end of lever A to ascend. Lever A pulls lever B to rotate hinge point B, causing the free end of lever B to ascend and the front end of lever B to descend. At this point, the movement process of "lower right and upper left" is realized.

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