CN210352212U

CN210352212U - Small-size maize picker

Info

Publication number: CN210352212U
Application number: CN201921249440.5U
Authority: CN
Inventors: 朱祥然
Original assignee: Yuzhou Yusheng Machinery Manufacturing Co ltd
Current assignee: Yuzhou Yusheng Machinery Manufacturing Co ltd
Priority date: 2019-08-05
Filing date: 2019-08-05
Publication date: 2020-04-21
Anticipated expiration: 2029-08-05

Abstract

A small-sized corn harvester belongs to the field of corn harvesting machinery and comprises an ear picking device, a hopper, a power input wheel, a gear box, a grain cutting transmission mechanism, a frame, a connecting frame, a straw sending-out device and a grain cutting mechanism; the ear picking device is arranged on the frame, is connected with the gearbox, and can pick corn ears on the corn straws and roll the corn ears into the hopper; the hopper is arranged on the frame, is positioned at the lower parts of the two sides of the ear picking device and is provided with a guide plate; the corn harvesting and straw harvesting machine has the characteristics that the corn harvesting and straw harvesting on a small land can be realized, the working procedure that the harvested corn and straw can be output only in one direction when the machine is suitable for the single-ridge operation of a small-sized harvester is realized, the machine does not need to be backed repeatedly, the straw is transversely placed on a ridge, the manual collection and the mechanical collection and bundling are facilitated, and the next step of transportation and the application of the straw as feed or other materials are facilitated.

Description

Small-size maize picker

Technical Field

The invention belongs to the field of agricultural machinery, and particularly relates to a corn harvester for small farmlands in mountainous areas or hilly areas.

Background

Corn is one of the main crops in China, and due to the characteristics of drought and waterlogging tolerance and low requirement on soil, the corn is used as a crop option for being planted in small plots in mountainous areas or hilly areas; in mountainous areas and hilly areas, due to the reasons of small land mass, thin land and irregular terrain, the corn is harvested manually; along with the development of agricultural machinery technology, can adopt small-size maize picker to gather in to above-mentioned landmass, but when the results, often only with maize results, the maize straw is still in the soil, moreover because the soil horizon of soil is thin, can not adopt rotary tillage machinery to carry out the straw and return the field operation, only with the straw burning, along with the improvement of environmental protection requirement, the straw that burns is forbidden in every place, has brought the inconvenience for the peasant in above-mentioned area plants maize.

Disclosure of Invention

The invention provides a small-sized corn harvester aiming at the problems of planting corn in small plots in the existing mountainous area or hilly area, which is characterized in that: comprises a snapping device, a hopper, a power input wheel, a gear box, a grain cutting transmission mechanism, a frame, a connecting frame, a straw delivery device and a grain cutting mechanism; the ear picking device is arranged on the frame, is connected with the gearbox, and can pick corn ears on the corn straws and roll the corn ears into the hopper; the hopper is arranged on the frame, is positioned at the lower parts of the two sides of the ear picking device and is provided with a guide plate; the two hoppers are positioned at two sides of the ear picking device, and the position of the guide plate is adjusted to determine which hopper at one side can enter the corn ear; the power input wheel is arranged on a power input shaft of the gearbox, is fixedly connected with the power input shaft and is connected with a power output wheel of the small agricultural power machine through a transmission mechanism; the gearbox is arranged on the rack and fixedly connected with the rack; the power input shaft is connected with the power input wheel, and the power output shaft is respectively connected with the two snapping rolls and the cutting transmission mechanism, so that the two snapping rolls are ensured to rotate in opposite directions and relatively rotate inwards; the cutting transmission mechanism is arranged on the frame, is connected with a power output wheel at the end part of the gearbox through a chain or a belt, and drives the two shifting wheels to rotate oppositely and the cutter to rotate; the machine frame is arranged on the connecting frame, the upper part of the machine frame is connected with the gearbox, the two sides of the machine frame are connected with the hopper, and the lower part of the machine frame is connected with the straw cutting mechanism and the straw feeding device; the connecting frame is arranged at one end of the frame, and a connecting structure on the connecting frame is matched with a connecting part of the small agricultural power machine; the small agricultural power machine comprises a small tractor or other small self-propelled power machines; fixedly connected with a small power machine; the straw feeding-out device is arranged on the frame and can transversely feed out the straws cut by the straw cutting mechanism from two sides of the machine; the straw cutting mechanism is arranged on the frame and can cut the straws and feed the straws into the straw delivery device backwards by being driven by the straw cutting transmission mechanism.

Furthermore, the cutting transmission device comprises a bearing seat, a transmission shaft, a right driving gear, a left driving gear, a driven gear, a power wheel and a transmission chain; the two bearing seats are respectively arranged at two ends of the transmission shaft and connected with the transmission shaft through bearings, the transmission shaft can rotate on the bearing seats, and the upper parts of the bearing seats are fixedly connected with the rack; the transmission shaft is arranged on the bearing seat and is connected with the bearing seat through a bearing; the left end of the middle part of the power wheel is fixedly connected with the power wheel; the right driving gear is arranged on the transmission shaft and fixedly connected with the transmission shaft, and the tooth part of the right driving gear is meshed with the tooth part of the driven gear arranged at the upper end of the right thumb wheel; the right driving gear is a bevel gear; the left driving gear is arranged on the transmission shaft and is a conical gear, is arranged in a back direction or opposite direction with the right driving gear and is fixedly connected with the transmission shaft, and the tooth part of the left driving gear is meshed with the tooth part of the driven gear arranged on the left thumb wheel; the two driven gears are respectively arranged at the upper ends of the left thumb wheel and the right thumb wheel and are fixedly connected with the left thumb wheel and the right thumb wheel; the power wheel is arranged on the transmission shaft, is fixedly connected with the transmission shaft and is connected with a power output wheel at the end part of the gearbox through a transmission chain; the transmission chain is a transmission belt or a chain, is arranged between the power output wheel and the power wheel at the end part of the gearbox, and can transmit power to the power wheel.

Further, the straw discharging device comprises a bottom plate, a guide plate, a reversing shaft and a reversing pull rod; the bottom plate is arranged at the bottom of the guide plate, is fixedly connected with the guide plate and supports and installs the straw cutting mechanism; the two guide plates are arranged on the bottom plate, the lower end of each guide plate is fixedly connected with the bottom plate, and the upper end of each guide plate is fixedly connected with the rack; the guide plate is arc-shaped; the reversing plate is arranged at the joint of the two arc-shaped guide plates, ensures that the plane of the reversing plate is flush with the arc-shaped surface of the guide plate, is fixedly connected with the reversing shaft and can swing around the reversing shaft; the reversing shaft is arranged on the reversing plate, is fixedly connected with the reversing plate, extends out of the upper end surface and the lower end surface of the reversing plate, is connected with the bottom plate at the lower end and is connected with the rack at the upper end, and can rotate on the bottom plate and the rack; the reversing pull rod is arranged at the lower end or the upper end of the reversing shaft, is fixedly connected with the reversing shaft and is connected with an operation table of the small agricultural power machine through an operation pull rod or a pull wire; the reversing pull rod can be pulled to rotate the reversing shaft by operating the pull rod or the pull wire, and the rotating angle of the reversing shaft is adjusted by a limiting device arranged on the bottom plate or the rack; the limiting adjusting device is arranged on the bottom plate or the rack and positioned on two sides of the reversing pull rod, and can limit the motion amplitude of the reversing pull rod.

Further, the straw cutting mechanism comprises a cutter, a left shifting wheel and a right shifting wheel; the cutter is arranged at the lower end of the left shifting wheel or the right shifting wheel and is fixedly connected with the left shifting wheel or the right shifting wheel; the cutter is round or radial, and the maximum diameter of the cutter is larger than that of the left shifting wheel or the right shifting wheel; the cutter is a serrated cutter; the left shifting wheel is arranged on a bottom plate of the straw delivery device, a shifting wheel installation shaft is arranged on the bottom plate, the shifting wheel installation shaft is fixedly connected with the bottom plate, and the left shifting wheel is connected with the installation shaft through a bearing; the left thumb wheel can rotate on the thumb wheel mounting shaft; the left thumb wheel is of a hollow structure; fins are uniformly arranged on the outer circumference of the left thumb wheel, the fins are in a spiral strip shape, and the spiral direction of the fins is right-handed; the distance between the wing pieces is the same as that between the wing pieces on the right thumb wheel; the right thumb wheel is arranged on a bottom plate of the straw delivery device, a thumb wheel mounting shaft is arranged on the bottom plate, the thumb wheel mounting shaft is fixedly connected with the bottom plate, and the right thumb wheel is connected with the thumb wheel mounting shaft through a bearing; the right thumb wheel can rotate on the thumb wheel mounting shaft; the right thumb wheel is of a hollow structure; fins are uniformly arranged on the outer circumference of the right thumb wheel, the fins are in a spiral strip shape, and the spiral direction of the fins is left-handed; the distance between the wing pieces is the same as that of the wing pieces on the left thumb wheel; the distance between the left thumb wheel and the right thumb wheel is larger than the diameter of the wheel bodies of the two thumb wheels and is smaller than twice of the rotating diameter of the wing panel; the helix angles of the wing pieces on the left thumb wheel and the right thumb wheel are the same or close to each other; the upper parts of the left thumb wheel and the right thumb wheel are fixedly connected with the driven gear.

The front, back, left, right, up and down equidirectional directions all use the facing view and one end of the connecting frame is the rear end.

Advantageous effects

The small-sized harvester has the advantages that the small-sized harvester can harvest corn and reap straw in a small land, can adapt to the working procedure that the harvested corn and the harvested straw can be output only in one direction during single-ridge operation of the small-sized harvester, does not need to be backed repeatedly, and is transversely placed on ridges of a field, so that manual collection and mechanical collection and bundling are facilitated, and further, the next step of transportation and application of the straw as feed or other materials are facilitated.

Drawings

Fig. 1 is a schematic structural view of the present invention.

1. The straw harvester comprises a snapping device, a hopper, a power input wheel, a gearbox, a straw cutting transmission mechanism, a rack, a connecting frame, a straw feeding-out device and a straw cutting mechanism, wherein the snapping device comprises a snapping device 2, the hopper, a power input wheel 3, the gearbox 4, the straw cutting transmission mechanism 5, the rack 6, the connecting frame 7, the straw feeding-out device 8 and the straw cutting mechanism 9.

Fig. 2 is a schematic view of the lower structure of the present invention.

51. The cutting machine comprises a bearing block, 52. a transmission shaft, 53. a right driving gear, 54. a left driving gear, 55. a driven gear, 56. a power wheel, 57. a transmission chain, 81. a bottom plate, 82. a left guide plate, 83. a right guide plate, 84. a reversing plate, 91. a cutter, 92. a left thumb wheel and 93. a right thumb wheel.

Detailed Description

To further explain the technical solution of the present invention, the detailed embodiment of the present invention will be described with reference to the accompanying drawings, as shown in fig. 1 and fig. 2, in this example, a circular saw blade commonly used in the industry is selected as a cutting knife 91, and the cutting knife 91 is installed at the lower end of a left thumb wheel 92 and is fixedly connected with the left thumb wheel 92; its maximum diameter is greater than the maximum diameter of the left thumb wheel 92; in the embodiment, a steel plate is selected and welded into a hollow cylinder, and fins are arranged on the outer cylindrical surface of the hollow cylinder to serve as the left thumb wheel 92, the number of the fins is 36, the fins are right-handed and are uniformly distributed on the cylindrical surface of the left thumb wheel 92 and are parallel to each other; the height of the wing pieces is 20-30 mm, and the right-handed rotation refers to the rotation of the wing pieces facing the cylindrical surface from top to bottom to the right; the left thumb wheel 92 is arranged on a bottom plate 81 of the straw feeding device 8, a thumb wheel mounting shaft is arranged on the bottom plate 81, the thumb wheel mounting shaft is fixedly connected with the bottom plate 81, and the left thumb wheel 92 is connected with the mounting shaft through a bearing; the left thumb wheel 92 can rotate on the thumb wheel mounting shaft; in the embodiment, a structure that fins are arranged outside a hollow cylinder with the same diameter and height as the left thumb wheel 92 is used as the right thumb wheel 93, the right thumb wheel 93 is arranged on a bottom plate 81 of the straw feeding device 8, a thumb wheel mounting shaft is arranged on the bottom plate 81, the thumb wheel mounting shaft is fixedly connected with the bottom plate 81, and the left thumb wheel is connected with the thumb wheel mounting shaft through a bearing; the right thumb wheel can rotate on the thumb wheel mounting shaft; the wing pieces on the right thumb wheel 93 adopt the same specification and layout form as the wing pieces on the left thumb wheel 92, but the spiral direction is left-handed, the left-handed refers to the cylindrical surface facing the right thumb wheel 93, and the wing pieces extend leftwards from top to bottom; meanwhile, the central distance between the left thumb wheel 92 and the right thumb wheel 93 is ensured to be more than two times of the wheel body diameter of the two thumb wheels and less than two times of the maximum rotation diameter of the wing panel; the distance from the outer edge of one wing piece to the outer surface of the other thumb wheel cylinder is preferably smaller than the minimum diameter of the straw; the helix angles of the wing pieces on the left thumb wheel and the right thumb wheel are the same or close to each other; and finally, the upper parts of the left thumb wheel 92 and the right thumb wheel 93 are welded or fixedly connected with a driven gear through a welding mounting shaft, so that the implementation of the straw cutting mechanism 9 is completed.

In this example, bearing blocks commonly used in the industry are used as the bearing blocks 51, two of the bearing blocks 51 are respectively installed at two ends of the transmission shaft 52 and connected with the transmission shaft 52 through bearings, so that the transmission shaft 52 can rotate on the bearing blocks 51, and the upper part of the bearing block 51 is fixedly connected with the frame 6; the transmission shaft 52 is arranged on the bearing seat 51 and is connected with the bearing seat 51 through a bearing; the left end of the middle part of the power wheel is fixedly connected with the power wheel 56; the right driving gear 53 is arranged on the transmission shaft 52 and is fixedly connected with the transmission shaft 52, and the tooth part of the right driving gear is meshed with the tooth part of the driven gear 55 arranged at the upper end of the right thumb wheel 93; the right driving gear 53 is selected as a bevel gear; the left driving gear 54 is installed on the transmission shaft 52 and is a bevel gear, and is installed back to back or opposite to the right driving gear 53, that is, the teeth ends of the two bevel gears are opposite or deviated; this ensures that when the transmission shaft 52 drives the right driving gear 53 and the left driving gear 54 to rotate in one direction simultaneously, the two driven gears 55 rotate in opposite directions, which in this case requires that the two driven gears 55 must rotate in opposite directions, i.e. stand at the front end, and the outer cylindrical surface of the driven gear moves towards the middle of the two gears; fixedly connecting the left driving gear 54 with the transmission shaft 52, wherein the tooth part of the left driving gear is meshed with the tooth part of the driven gear 55 arranged on the left thumb wheel 92; two driven gears 55 are respectively arranged at the upper ends of the left thumb wheel 92 and the right thumb wheel 93 and fixedly connected with the left thumb wheel 92 and the right thumb wheel 93; the power wheel 56 is arranged at the end part of the transmission shaft 52, is fixedly connected with the transmission shaft 52 and is connected with the power output wheel at the end part of the gearbox through a chain; a chain is selected as a transmission chain 57, the transmission chain is arranged between a power output wheel at the end part of the gearbox and the power wheel 56, the power output by the gearbox can be transmitted to the power wheel 56, and the implementation of the grass cutting transmission mechanism 5 is completed.

In the embodiment, a steel plate is used as a bottom plate 81, the bottom plate 81 is arranged at the bottom of the guide plate and fixedly connected with the guide plate, and the grass cutting mechanism 9 is supported and arranged; in this example, an arc-shaped steel plate is selected as a guide plate, the two guide plates are a left guide plate 82 and a right guide plate 83, one ends of the left guide plate 82 and the right guide plate 83 are butted, the other ends of the left guide plate 82 and the right guide plate 83 are separately arranged on the bottom plate 81 towards two sides, the lower ends of the left guide plate 82 and the right guide plate are smoothly welded with the bottom plate 81, and the upper ends of the left guide plate and the right guide plate; in this example, a rectangular steel plate is used as the reversing plate 84, the height of the rectangular steel plate is less than or equal to that of the guide plates, reversing shafts are welded at two ends of one side edge, the reversing plate 84 is installed at the joint of the two arc-shaped guide plates, the plane of the reversing plate is ensured to be flush with the arc-shaped surfaces of the guide plates, the reversing shafts are ensured to extend out of the upper end surface and the lower end surface of the reversing plate 84, the reversing shafts at the lower end are sleeved with the reversing shaft installation holes in the bottom plate 81, and the reversing shafts at the upper end are sleeved with the reversing shaft installation holes in the rack 6, so that the reversing shafts can; in the embodiment, holes are punched at two ends of a strip-shaped steel plate to be used as a reversing pull rod, the reversing pull rod is arranged at the lower end or the upper end of a reversing shaft and is fixedly connected with the reversing shaft, and the reversing pull rod is connected with an operation table of the small agricultural power machine through an operation pull rod or a pull wire; the reversing pull rod can be pulled to rotate the reversing shaft by operating the pull rod or the pull wire, and the rotating angle of the reversing shaft is adjusted by a limiting device arranged on the bottom plate 81 or the rack 6; the limiting adjusting devices are arranged on the bottom plate 81 or the rack 6 and are positioned on two sides of the reversing pull rod, so that the motion amplitude of the reversing pull rod can be limited, and the implementation of the straw discharging device 8 is completed.

In the embodiment, a snapping device of a single-row corn harvester commonly used in the industry is selected as the snapping device 1, the snapping device 1 is arranged on a gear box 4 and is connected with a 6, and corn ears on corn straws can be picked and rolled into a hopper 2; in the embodiment, a hopper of a Chinese patent (application number: 2018109213001) applied in the prior art is selected as the hopper 2, the hopper 2 is arranged on the frame 6 and positioned at the lower parts of the two sides of the ear picking device 1, and guide plates are arranged on the hopper 2; two hoppers 2 are selected and positioned at two sides of the ear picking device 1, and the position of the guide plate is adjusted to determine which hopper 2 at one side can enter the corn ear; in the embodiment, a small-sized walking tractor is selected as a small-sized agricultural power machine, a belt pulley matched with a belt pulley on the walking tractor is selected as a power input wheel 3, the power input wheel 3 is arranged on a power input shaft of a gearbox 4 and is fixedly connected with the power input shaft, and the power input shaft is connected with a power output wheel of the small-sized agricultural power machine through a transmission belt; in the embodiment, a gearbox of a single-row corn harvester which is commonly used in the industry is selected as the gearbox 4, a power output shaft is led out from the end part of the gearbox 4, and the gearbox 4 is arranged on the frame 6 and fixedly connected with the frame 6; the power input shaft of the harvester is connected with a power input wheel 3, and the power output shaft of the harvester is respectively connected with the two snapping rolls and the cutting transmission mechanism 5, so that the two snapping rolls are ensured to rotate in opposite directions and relatively rotate inwards, namely the cylindrical surfaces of the snapping rolls move inwards when viewed from top to bottom; the seedling cutting transmission mechanism 5 is arranged on a frame 6, is connected with a power output wheel at the end part of a gearbox through a chain, and drives two shifting wheels to rotate oppositely and a cutter 91 to rotate; in the embodiment, a rack structure of a small single-row corn harvester which is commonly used in the industry and is formed by welding rectangular steel pipes and steel plates is used as a rack 6, the rack 6 is arranged on a connecting frame 7, the upper part of the rack is connected with a gear box 4, the two sides of the rack are connected with a hopper 3, and the lower part of the rack is connected with a grain cutting mechanism 9 and a straw feeding device 8; in the embodiment, a steel plate with the thickness of 8-10 mm is selected and welded into a T shape, a connecting hole is manufactured on the T shape to be used as a connecting frame 7, the connecting frame 7 is installed at the rear end of a frame 6, the connecting hole on the connecting frame is matched with a connecting part of a small agricultural power machine, and the connecting frame is connected and fixed by bolts; the straw feeding-out device 8 is arranged on the frame 6, and can transversely feed out the straws cut by the straw cutting mechanism 9 from two sides of the machine; the straw cutting mechanism 9 is arranged between the frame 6 and the straw delivery device, and is driven by the straw cutting transmission mechanism 5 to cut the straws and deliver the straws to the straw delivery device 8 backwards, thus completing the implementation of the invention.

When the corn harvester is applied, in order to adapt to the corn harvesting operation of small plots in mountainous areas, a single-row reciprocating harvesting mode is adopted, a hand tractor is started, two driving wheels of the hand tractor straddle two sides of a field ridge, the middle part of single-row corn enters the ear picking device 1, the lower part of the single-row corn enters the seedling cutting mechanism 9, two ear picking rollers of the ear picking device 1 enable corn straws to pass through between the two ear picking rollers, the corn ears are picked and rolled into the hopper 2, the straws are conveyed downwards forcibly, after the lower part of the straws are cut off by the seedling cutting mechanism 9, the lower ends of the straws are conveyed upwards and backwards forcibly by the two shifting wheels under the action of fins on the shifting wheels, and the power of the ear picking rollers is combined with the power of the shifting wheels to enable the straws to rapidly enter the straw sending-out device 8 and to be sent out to one harvested side under the action; when a row of corns are harvested and fallen to the ground, the walking tractor turns around backwards to harvest from the other direction, the guide plates on the hopper 2 are operated to enable the corn ears to enter the hopper 2 positioned at one side of the harvested land blocks, meanwhile, the reversing plate 84 of the straw sending-out device 8 is adjusted to cover the output channel of the guide plate (82 or 83) at the non-harvested side, and the straws slide to the guide plate (82 or 83) positioned at one side of the harvested land blocks from the surface of the reversing plate 84 and are sent out; the results that just can accomplish the hilly area plot maize of reciprocal results just like this and transversely put the straw, for manual collection or mechanical collection bundle provide the advantage, reduced the pollution that the burning straw caused, cleared up the plot simultaneously, are favorable to the planting in next season.

Claims

1. A small-size maize picker which characterized in that: comprises a snapping device, a hopper, a power input wheel, a gear box, a grain cutting transmission mechanism, a frame, a connecting frame, a straw delivery device and a grain cutting mechanism; the ear picking device is arranged on the frame, is connected with the gearbox, and can pick corn ears on the corn straws and roll the corn ears into the hopper; the hopper is arranged on the frame, is positioned at the lower parts of the two sides of the ear picking device and is provided with a guide plate; the two hoppers are positioned at two sides of the ear picking device, and the position of the guide plate is adjusted to determine which hopper at one side can enter the corn ear; the power input wheel is arranged on a power input shaft of the gearbox, is fixedly connected with the power input shaft and is connected with a power output wheel of the small agricultural power machine through a transmission mechanism; the gearbox is arranged on the rack and fixedly connected with the rack; the power input shaft is connected with the power input wheel, and the power output shaft is respectively connected with the two snapping rolls and the cutting transmission mechanism, so that the two snapping rolls are ensured to rotate in opposite directions and relatively rotate inwards; the cutting transmission mechanism is arranged on the frame, is connected with a power output wheel at the end part of the gearbox through a chain or a belt, and drives the two shifting wheels to rotate oppositely and the cutter to rotate; the machine frame is arranged on the connecting frame, the upper part of the machine frame is connected with the gearbox, the two sides of the machine frame are connected with the hopper, and the lower part of the machine frame is connected with the straw cutting mechanism and the straw feeding device; the connecting frame is arranged at one end of the frame, and a connecting structure on the connecting frame is matched with a connecting part of the small agricultural power machine; fixedly connected with a small power machine; the straw feeding-out device is arranged on the frame and can transversely feed out the straws cut by the straw cutting mechanism from two sides of the machine; the straw cutting mechanism is arranged on the frame and can cut the straws and feed the straws into the straw delivery device backwards by being driven by the straw cutting transmission mechanism.

2. The small corn harvester of claim 1, wherein: the small agricultural power machine is a small walking tractor or a small self-propelled power machine.

3. The small corn harvester of claim 1, wherein: the cutting transmission mechanism comprises a bearing seat, a transmission shaft, a right driving gear, a left driving gear, a driven gear, a power wheel and a transmission chain; the two bearing seats are respectively arranged at two ends of the transmission shaft and connected with the transmission shaft through bearings, the transmission shaft can rotate on the bearing seats, and the upper parts of the bearing seats are fixedly connected with the rack; the transmission shaft is arranged on the bearing seat and is connected with the bearing seat through a bearing; the left end of the middle part of the power wheel is fixedly connected with the power wheel; the right driving gear is arranged on the transmission shaft and fixedly connected with the transmission shaft, and the tooth part of the right driving gear is meshed with the tooth part of the driven gear arranged at the upper end of the right thumb wheel; the right driving gear is a bevel gear; the left driving gear is arranged on the transmission shaft and is a conical gear, is arranged in a back direction or opposite direction with the right driving gear and is fixedly connected with the transmission shaft, and the tooth part of the left driving gear is meshed with the tooth part of the driven gear arranged on the left thumb wheel; the two driven gears are respectively arranged at the upper ends of the left thumb wheel and the right thumb wheel and are fixedly connected with the left thumb wheel and the right thumb wheel; the power wheel is arranged on the transmission shaft, is fixedly connected with the transmission shaft and is connected with a power output wheel at the end part of the gearbox through a transmission chain; the transmission chain is a transmission belt or a chain, is arranged between the power output wheel and the power wheel at the end part of the gearbox, and can transmit power to the power wheel.