Farm tool traction mechanism of tractor chassis

Abstract

The invention relates to the field of agricultural machinery, in particular to a farm tool traction mechanism of a tractor chassis, which comprises a rear axle box body of a tractor, an upper pull rod and a lower pull rod which can swing up and down are hinged to the rear end of the rear axle box body, and a lifting frame is hinged to the rear end of the rear axle box body between the two lower pull rods and is driven by a hydraulic device to swing up and down. The rotating axis of the lifting frame coincides with the rotating axis of the lower pull rod, and an elastic supporting piece is connected between the lifting frame and the lower pull rod. In the process that a tractor carries farm tools to transfer and transport the farm tools, the spring shock absorber provides a shock absorption effect for the lower pull rod and the farm tools.

Description

Technical Field

[0001] The invention relates to the field of agricultural machinery, and in particular to an agricultural implement traction mechanism of a tractor chassis. Background Art

[0002] Most of the existing structures of tractors pulling farm implements use a limited pull rod structure to provide pulling force under the drive of a hydraulic cylinder to achieve the lifting and lowering of farm implements and the adjustment of working positions. For example, the utility model patent with application number CN222097777U discloses a tractor and agricultural machinery, in which a suspension for connecting is provided at one end of the rear frame of the tractor away from the front frame, and the suspension specifically includes a lifting arm, and an upper pull rod and a lower pull rod arranged on one side of the lifting arm, and the farm implement is arranged on the upper pull rod and the lower pull rod, and during operation, the height of the farm implement can be raised in real time by the lifting arm as needed.

[0003] However, there is no buffer structure between the existing tractor and the farm implement. When the tractor lifts the farm implement for transfer after finishing the work, the bumps caused by the uneven road surface on the tractor will be directly transmitted to the farm implement, which can easily cause damage to the farm implement. Summary of the invention

[0004] The object of the present invention is to provide an agricultural implement traction mechanism for a tractor chassis, which can reduce the vibration transmitted to the agricultural implement when the tractor is running, so as to solve the defects mentioned in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A farm implement traction mechanism of a tractor chassis comprises a rear axle box of the tractor, wherein an upper pull rod and a lower pull rod which can swing up and down are hinged at the rear end of the rear axle box, a lifting frame is hinged at the rear end of the rear axle box located between the two lower pull rods, the lifting frame is driven by a hydraulic device to swing up and down, the axis of rotation of the lifting frame coincides with the axis of rotation of the lower pull rod, and an elastic support member is connected between the lifting frame and the lower pull rod.

[0006] As a preferred technical solution, the elastic support member is a spring damper, one end of which is hinged to the lower pull rod and the other end is hinged to the lifting frame, and the spring damper is compressed when the lower pull rod swings downward relative to the lifting frame.

[0007] As a preferred technical solution, the lifting frame includes a mounting shaft extending in the width direction of the tractor. The mounting shaft is rotatably mounted at the rear end of the rear axle housing. Swing arms extending radially along the mounting shaft are fixedly installed at both ends of the mounting shaft. Elastic support members are respectively connected between the lower pull rod and the corresponding swing arm on one side; a sliding sleeve is slidably mounted on the swing arm along its length direction. A sliding pin extending along the length direction of the mounting shaft is fixedly installed on the sliding sleeve. An adjustment groove matching the sliding pin is provided on the lower pull rod. The sliding pin is slidably mounted in the corresponding adjustment groove; the adjustment groove includes an arc groove and a straight groove. One end of the arc groove communicates with one end of the straight groove. The center of the arc groove coincides with the mounting shaft. The length direction of the straight groove extends along the radial direction of the mounting shaft.

[0008] As a preferred technical solution, when the sliding pin is adjusted to the end where the straight groove communicates with the arc groove, the lower pull rod can swing up and down relative to the lifting frame under the support of the elastic support member; when the sliding pin is adjusted to the end of the straight groove far from the arc groove, the lower pull rod cannot swing up and down relative to the lifting frame.

[0009] As a preferred technical solution, when the elastic support member is in a natural state, the sliding pin is located on the straight line where the straight groove is located.

[0010] As a preferred technical solution, a fixing plate is fixedly installed on the two swing arms. An adjusting oil cylinder is installed on the fixing plate. The piston rod of the adjusting oil cylinder extends along the length direction of the straight groove. A movable plate is fixedly installed on the piston rod of the adjusting oil cylinder. The sliding sleeve is fixedly installed on the movable plate.

[0011] As a preferred technical solution, a connecting shaft parallel to the mounting shaft is fixedly installed between the two sliding sleeves. A support frame is fixedly installed on the rear axle housing. A guiding groove matching the connecting shaft is provided on the support frame. The guiding groove penetrates the support frame along the length direction of the connecting shaft. The connecting shaft is movably installed in the guiding groove. When the lifting frame swings up and down, the guiding groove acts on the connecting shaft and drives the sliding sleeve to slide along the swing arm.

[0012] As a preferred technical solution, the guiding groove includes an arc portion and a straight portion. One end of the arc portion communicates with one end of the straight portion. The center of the arc portion coincides with the mounting shaft. The distance between the end of the straight portion far from the arc portion and the mounting shaft is less than the radius of the arc portion, and the straight portion does not coincide with the radius of the mounting shaft; the distance between the end of the straight groove far from the arc groove and the mounting shaft is greater than the radius of the arc groove.

[0013] As a preferred technical solution, when the lifting frame swings upward, the lifting frame drives the connecting shaft to enter the straight portion through the arc portion and move along the straight portion toward the direction close to the mounting shaft. At the same time, the sliding sleeve drives the sliding pin to move to one end where the straight groove communicates with the arc groove. When the lifting frame swings downward, the lifting frame drives the connecting shaft to move along the straight portion away from the mounting shaft and enter the arc portion. At the same time, the sliding sleeve drives the sliding pin to move to one end of the straight groove away from the arc groove.

[0014] As a preferred technical solution, a rotation sleeve arranged coaxially is rotatably mounted on the outer side of the connecting shaft, and the rotation sleeve is in rolling fit with the inner wall of the guide groove.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: During the process of the tractor carrying agricultural implements for transfer transportation, the sliding pin is adjusted to one end where the straight groove communicates with the arc groove, so as to release the locking between the lower pull rod and the lifting frame. When the tractor jolts due to uneven road surface, the lower pull rod can swing downward relative to the lifting frame and compress the spring shock absorber. The spring shock absorber provides a shock-absorbing effect for the lower pull rod and the agricultural implements, reduces the vibration transmitted by the tractor to the agricultural implements, and avoids damage to the agricultural implements. When the tractor drives the agricultural implements to perform operations, the sliding pin is adjusted to one end of the straight groove away from the arc groove, so as to lock the lower pull rod and the lifting frame. The sliding pin restricts the up-and-down swing of the lower pull rod relative to the lifting frame, so that the up-and-down swing of the lifting frame can drive the lower pull rod and the agricultural implements to accurately rotate to the required height, ensuring the normal operation of the agricultural implements. In this application, the locking between the lower pull rod and the lifting frame can be released by adjusting the cylinder to extend and drive the movable plate and the sliding sleeve to move toward the direction close to the mounting shaft, so that the sliding pin enters one end where the straight groove communicates with the arc groove. Or the locking between the lower pull rod and the lifting frame can be locked by adjusting the cylinder to contract and drive the movable plate and the sliding sleeve to move away from the mounting shaft, so that the sliding pin enters one end of the straight groove away from the arc groove. The locking state of the lower pull rod and the lifting frame can be flexibly adjusted through the adjusting cylinder. When the agricultural implement is lifted to a preset height in this application, the sliding pin enters one end where the straight groove communicates with the arc groove under the guiding action of the guide groove, so as to automatically release the locking between the lower pull rod and the lifting frame. Or after the agricultural implement descends to a certain height, the sliding pin moves to one end of the straight groove away from the arc groove under the guiding action of the guide groove, so as to automatically lock the lower pull rod and the lifting frame. There is no need for manual intervention in the locking state of the lower pull rod and the lifting frame, and it is more convenient to use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0017] Figure 1 is a schematic structural diagram of Embodiment 1 of the present invention; Figure 2 is a schematic structural diagram of the lifting frame of Embodiment 1 of the present invention; Figure 3 is a schematic structural diagram of the adjustment groove of Embodiment 1 of the present invention; Figure 4 is a schematic diagram when the lower pull rod and the lifting frame of Embodiment 1 of the present invention are unlocked; Figure 5 is a schematic structural diagram of Embodiment 2 of the present invention; Figure 6 is a schematic structural diagram of the lifting frame of Embodiment 2 of the present invention; Figure 7 is a schematic structural diagram of the connecting shaft of Embodiment 2 of the present invention; Figure 8 is a schematic structural diagram of the guide groove of Embodiment 2 of the present invention; Figure 9 is a schematic diagram when the lower pull rod and the lifting frame of Embodiment 2 of the present invention are unlocked.

[0018] In the figure: 1 - rear axle housing; 2 - upper pull rod; 3 - lower pull rod; 4 - lifting frame; 5 - mounting shaft; 6 - hinge seat; 7 - swing arm; 8 - lifting oil cylinder; 9 - pull plate; 10 - spring shock absorber; 11 - sliding sleeve; 12 - sliding pin; 13 - adjustment groove; 14 - arc groove; 15 - straight groove; 16 - fixed plate; 17 - adjustment oil cylinder; 18 - movable plate; 19 - connecting shaft; 20 - support frame; 21 - front end plate; 22 - side plate; 23 - guide groove; 24 - arc portion; 25 - straight portion; 26 - rotating sleeve; 27 - connecting plate. Detailed implementation manners

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0020] Embodiment 1: As Figures 1 to 4As shown in the figure, an implement towing mechanism for a tractor chassis includes a rear axle housing 1 of the tractor. A top link 2 and a lower link 3 that can swing up and down are hinged to the rear end of the rear axle housing 1. Specifically, the two lower links 3 are arranged relatively left and right along the width direction of the tractor. The top link 2 is located above the two lower links 3. The front ends of the top link 2 and the lower links 3 are respectively hinged to the rear axle housing 1, and the rear ends are used to connect the implement.

[0021] A lifting frame 4 is hinged to the rear end of the rear axle housing 1 between the two lower links 3. As Figure 2 shown, the lifting frame 4 includes a mounting shaft 5 extending transversely along the width direction of the tractor. A hinge seat 6 is fixedly installed at the rear end of the rear axle housing 1. The middle part of the mounting shaft 5 is rotatably installed on the hinge seat 6. The axis of the mounting shaft 5 coincides with the axis of rotation of the two lower links 3. Swing arms 7 extending radially along it are respectively fixedly installed at the left and right ends of the mounting shaft 5 by bolts. The lifting frame 4 is driven by a hydraulic device to swing up and down. The hydraulic device is specifically a lifting cylinder 8. The lifting cylinders 8 correspond to the swing arms 7 one by one. Two relatively left and right arranged pull plates 9 are fixedly installed at the top of the rear end of the rear axle housing 1 by bolts. One end of the lifting cylinder 8 is hinged to the corresponding pull plate 9, and the other end is hinged to the corresponding swing arm 7. The lifting frame 4 is driven to swing up and down by the telescopic movement of the lifting cylinder 8.

[0022] Elastic support members are respectively connected between the lower link 3 and the swing arm 7 on the corresponding side. The elastic support members are specifically spring shock absorbers 10. As Figure 4 shown, a connecting plate 27 extending upward is welded to the top of the lower link 3. One end of the spring shock absorber 10 is hinged to the inner side of the connecting plate 27, and the other end is inclined backward and hinged to the outer side of the corresponding swing arm 7. When the lower link 3 swings downward relative to the lifting frame 4, the spring shock absorber 10 can be compressed.

[0023] When the lifting cylinder 8 contracts, it drives the lifting frame 4 to swing upward. Then, the lifting frame 4 drives the lower link 3 to swing upward through the spring shock absorber 10, so that the implement connected to the lower link 3 is lifted upward; or when the lifting cylinder 8 extends, it drives the lifting frame 4 to swing downward. Then, the lifting frame 4 drives the lower link 3 to swing downward through the spring shock absorber 10, so that the implement connected to the lower link 3 descends. In addition, during the process of the tractor carrying the implement for transfer transportation, when the tractor jolts due to uneven road surfaces, the lower link 3 can swing downward relative to the lifting frame 4 and compress the spring shock absorber 10. The spring shock absorber 10 provides a shock-absorbing effect for the lower link 3 and the implement, reduces the vibration transmitted from the tractor to the implement, and avoids damage to the implement.

[0024] One end of the swing arm 7 close to the mounting shaft 5 is externally sleeved with a sliding sleeve 11 in the length direction thereof. On the sides of the two sliding sleeves 11 away from each other, sliding pins 12 extending left and right in the length direction of the mounting shaft 5 are respectively welded. An adjusting groove 13 matching the sliding pins 12 is provided on the lower pull rod 3. The adjusting groove 13 penetrates through the lower pull rod 3 left and right, and the sliding pins 12 are slidably mounted in the corresponding adjusting grooves 13. In this embodiment, as Figure 3 shown, the adjusting groove 13 includes an arc groove 14 and a straight groove 15. One end of the arc groove 14 is communicated with one end of the straight groove 15. The center of the arc groove 14 coincides with the mounting shaft 5. The length direction of the straight groove 15 extends along the radial direction of the mounting shaft 5, and the distance between the end of the straight groove 15 away from the arc groove 14 and the mounting shaft 5 is greater than the radius of the arc groove 14.

[0025] As Figure 4 shown, the sliding pins 12 are adjusted to the end where the straight groove 15 is communicated with the arc groove 14, so as to release the locking between the lower pull rod 3 and the lifting frame 4. The lower pull rod 3 can swing up and down relative to the lifting frame 4 under the support of the spring damper 10, and at the same time, the sliding pins 12 move in the arc groove 14, so as to damp the agricultural implement through the spring damper 10 during the process of the tractor carrying the agricultural implement for transfer transportation; as Figure 1 shown, the sliding pins 12 are adjusted to the end of the straight groove 15 away from the arc groove 14, so as to lock the lower pull rod 3 and the lifting frame 4. The up and down swing of the lower pull rod 3 relative to the lifting frame 4 is restricted by the sliding pins 12, so that when the tractor drives the agricultural implement to operate, the up and down swing of the lifting frame 4 can drive the lower pull rod 3 and the agricultural implement to accurately rotate to the required height.

[0026] In addition, when the spring damper 10 is in a natural extended state, the sliding pins 12 are located on the straight line where the straight groove 15 is located, and the inner wall of the end where the arc groove 14 is connected to the straight groove 15 is provided with a fillet transition, so as to facilitate the accurate movement of the sliding pins 12 from the arc groove 14 into the straight groove 15 and efficiently lock the lower pull rod 3.

[0027] In this embodiment, a fixing plate 16 is fixedly installed at one end of the two swing arms 7 far away from the mounting shaft 5 by bolts. An adjusting oil cylinder 17 is installed on the side of the fixing plate 16 close to the mounting shaft 5 by bolts. The piston rod of the adjusting oil cylinder 17 extends along the length direction of the linear groove 15. A movable plate 18 is fixedly installed on the piston rod of the adjusting oil cylinder 17 by bolts. The two sliding sleeves 11 are respectively fixedly installed at the left and right ends of the movable plate 18 by bolts. Specifically, when the spring shock absorber 10 is in a natural extended state, the adjusting oil cylinder 17 extends to drive the movable plate 18 and the sliding sleeve 11 to move towards the direction close to the mounting shaft 5. Further, the sliding sleeve 11 drives the sliding pin 12 to enter one end of the linear groove 15 communicating with the arc groove 14, so as to release the lock between the lower pull rod 3 and the lifting frame 4, and the spring shock absorber 10 is used to damp the agricultural implement; on the contrary, the adjusting oil cylinder 17 contracts to drive the movable plate 18 and the sliding sleeve 11 to move away from the mounting shaft 5. Further, the sliding sleeve 11 drives the sliding pin 12 to enter one end of the linear groove 15 far away from the arc groove 14, so as to lock the lower pull rod 3 and the lifting frame 4. The lifting frame 4 can accurately adjust the rotation angle of the lower pull rod 3, and the adjusting oil cylinder 17 can flexibly adjust the locking state between the lower pull rod 3 and the lifting frame 4.

[0028] Embodiment Two: As Figures 5 to 9 shown, the difference between this embodiment and Embodiment One is that a connecting shaft 19 parallel to the mounting shaft 5 is fixedly installed between the two sliding sleeves 11 by bolts. A support frame 20 is fixedly installed at the rear end of the rear axle housing 1 by bolts. The support frame 20 includes a front end plate 21, and side plates 22 bent backward are integrally formed at the left and right ends of the front end plate 21 respectively; the support frame 20 is located between the front ends of the two swing arms 7, and an avoidance notch for avoiding the hinge seat 6 is provided at the front end of the support frame 20. Guide grooves 23 matching the connecting shaft 19 are provided on both side plates 22. The guide grooves 23 penetrate the side plates 22 left and right along the length direction of the connecting shaft 19. The connecting shaft 19 is movably installed in the two guide grooves 23. When the lifting frame 4 swings up and down, the guide grooves 23 act on the connecting shaft 19 and drive the sliding sleeve 11 to slide along the swing arm 7.

[0029] As Figure 8 shown, the guide groove 23 includes an arc portion 24 and a straight portion 25. One end of the arc portion 24 is communicated with one end of the straight portion 25. The center of the arc portion 24 coincides with the mounting shaft 5. The distance between the end of the straight portion 25 far away from the arc portion 24 and the mounting shaft 5 is less than the radius of the arc portion 24, and the straight portion 25 does not coincide with the radius of the mounting shaft 5.

[0030] When the tractor finishes the operation, the contraction of the lifting cylinder 8 drives the lifting frame 4 to swing upward. The lifting frame 4 drives the lower pull rod 3 to swing upward through the spring shock absorber 10, lifting the farm implement upward. At the same time, the lifting frame 4 drives the connecting shaft 19 to enter the straight part 25 of the guide groove 23 through the arc part 24 and move along the straight part 25 in the direction close to the mounting shaft 5. Furthermore, the connecting shaft 19 drives the sliding sleeve 11 to move in the direction close to the mounting shaft 5, and the sliding sleeve 11 drives the sliding pin 12 to enter one end where the straight groove 15 communicates with the arc groove 14, as Figure 9 shown. Thus, when the farm implement is lifted upward to the preset height, the locking between the lower pull rod 3 and the lifting frame 4 will be automatically released. Or when the tractor drives the farm implement to operate, the extension of the lifting cylinder 8 drives the lifting frame 4 to swing downward. The lifting frame 4 drives the lower pull rod 3 to swing downward through the spring shock absorber 10, lowering the farm implement. At the same time, the lifting frame 4 drives the connecting shaft 19 to move along the straight part 25 of the guide groove 23 in the direction away from the mounting shaft 5 and enter the arc part 24. At the same time, the connecting shaft 19 drives the sliding sleeve 11 to move in the direction away from the mounting shaft 5, and the sliding sleeve 11 drives the sliding pin 12 to move to one end of the straight groove 15 away from the arc groove 14, as Figure 5 shown. Thus, after the farm implement descends to a certain height, the lower pull rod 3 and the lifting frame 4 will be automatically locked, without the need for manual intervention in the locking state of the lower pull rod 3 and the lifting frame 4, making it more convenient to use.

[0031] As Figure 7 shown, in this embodiment, a rotating sleeve 26 arranged coaxially is rotatably installed on the outer side of the connecting shaft 19. The rotating sleeve 26 is in rolling cooperation with the inner wall of the guide groove 23, and the inner wall of the connecting end of the arc part 24 and the straight part 25 is provided with a rounded transition to reduce the resistance of the connecting shaft 19 moving along the guide groove 23.

[0032] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and the descriptions in the specification are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. An implement towing mechanism for a tractor chassis, including the rear axle housing of the tractor. A vertically swingable upper pull rod and a lower pull rod are hinged to the rear end of the rear axle housing. It is characterized in that: The rear end of the rear axle housing located between the two lower pull rods is hinged with a lifting frame, the lifting frame is driven by a hydraulic device to swing up and down, the axis of rotation of the lifting frame coincides with the axis of rotation of the lower pull rods, and an elastic support member is connected between the lifting frame and the lower pull rods.

2. The farm implement towing mechanism of a tractor chassis according to claim 1, characterized in that: The elastic support member is a spring shock absorber, one end of the spring shock absorber is hinged on the lower pull rod, the other end is hinged on the lifting frame, and the spring shock absorber is compressed when the lower pull rod swings downward relative to the lifting frame.

3. The farm implement towing mechanism of a tractor chassis according to claim 1, characterized in that: The lifting frame includes a mounting shaft extending in the width direction of the tractor, the mounting shaft is rotatably mounted at the rear end of the rear axle housing, swing arms extending radially along its two ends are respectively and fixedly mounted on the mounting shaft, and the elastic support members are respectively connected between the lower pull rods and the corresponding swing arms on one side; a sliding sleeve is slidably mounted on the swing arm along its length direction, a sliding pin extending along the length direction of the mounting shaft is fixedly mounted on the sliding sleeve, an adjusting groove matching with the sliding pin is provided on the lower pull rod, and the sliding pin is slidably mounted in the corresponding adjusting groove; the adjusting groove includes an arc-shaped groove and a straight groove, one end of the arc-shaped groove is communicated with one end of the straight groove, the center of the arc-shaped groove coincides with the mounting shaft, and the length direction of the straight groove extends along the radial direction of the mounting shaft.

4. The implement towing mechanism of a tractor chassis according to claim 3, characterized in that: When the sliding pin is adjusted to the end where the straight groove is communicated with the arc-shaped groove, the lower pull rod can swing up and down relative to the lifting frame under the support of the elastic support member; when the sliding pin is adjusted to the end of the straight groove far from the arc-shaped groove, the lower pull rod cannot swing up and down relative to the lifting frame.

5. The implement towing mechanism of a tractor chassis according to claim 4, characterized in that: When the elastic support member is in a natural state, the sliding pin is located on the straight line where the straight groove is located.

6. The farm implement towing mechanism of a tractor chassis according to claim 5, characterized in that: A fixing plate is fixedly mounted on the two swing arms, an adjusting oil cylinder is mounted on the fixing plate, the piston rod of the adjusting oil cylinder extends along the length direction of the straight groove, a movable plate is fixedly mounted on the piston rod of the adjusting oil cylinder, and the sliding sleeve is fixedly mounted on the movable plate.

7. The farm implement towing mechanism of a tractor chassis according to claim 5, characterized in that: A connecting shaft parallel to the mounting shaft is fixedly mounted between the two sliding sleeves, a support frame is fixedly mounted on the rear axle housing, a guiding groove matching with the connecting shaft is provided on the support frame, the guiding groove penetrates through the support frame along the length direction of the connecting shaft, the connecting shaft is movably mounted in the guiding groove, and when the lifting frame swings up and down, the guiding groove acts on the connecting shaft and drives the sliding sleeve to slide along the swing arm.

8. The implement towing mechanism of a tractor chassis according to claim 7, characterized in that: The guiding groove includes an arc-shaped portion and a straight portion, one end of the arc-shaped portion is communicated with one end of the straight portion, the center of the arc-shaped portion coincides with the mounting shaft, the distance between the end of the straight portion far from the arc-shaped portion and the mounting shaft is less than the radius of the arc-shaped portion, and the straight portion does not coincide with the radius of the mounting shaft; the distance between the end of the straight groove far from the arc-shaped groove and the mounting shaft is greater than the radius of the arc-shaped groove.

9. The farm implement towing mechanism of a tractor chassis according to claim 8, characterized in that: When the lifting frame swings upward, the lifting frame drives the connecting shaft to enter the linear part through the arc part and move along the linear part in the direction close to the mounting shaft. At the same time, the sliding sleeve drives the sliding pin to move to one end where the linear groove communicates with the arc groove; when the lifting frame swings downward, the lifting frame drives the connecting shaft to move along the linear part in the direction away from the mounting shaft and enter the arc part. At the same time, the sliding sleeve drives the sliding pin to move to one end of the linear groove far from the arc groove.

10. The farm implement towing mechanism of a tractor chassis according to claim 7, characterized in that: A rotation sleeve arranged coaxially is rotatably mounted on the outer side of the connecting shaft, and the rotation sleeve is in rolling fit with the inner wall of the guide groove.

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