A lifter

Abstract

This invention belongs to the field of agricultural machinery, specifically disclosing a lifting device, which includes a housing, a lifting arm, a distributor main control valve, a lever arm hinged to the front end of the valve stem, an upper shift fork mechanism and a lower shift fork mechanism on the housing, which are respectively connected to the upper and lower ends of the lever arm; a first linkage mechanism is provided between the lifting arm and the lower shift fork mechanism; a guide vertical plate is provided on the housing, with a guide groove on the guide vertical plate, a guide shaft extending into the guide groove in the middle of the swing connecting plate, a second linkage mechanism between the lower end of the swing connecting plate and the upper shift fork mechanism, a position adjustment handle that can provide constraint to the second linkage mechanism is installed on the housing; a force adjustment handle is provided on the housing, a G-link is provided between the force adjustment handle and the middle of the swing connecting plate; a swing support is provided at the rear end of the housing, a third linkage mechanism is provided between the upper end of the swing support and the upper end of the swing connecting plate. This invention realizes comprehensive force and position adjustment and stable lifting control of the lifting device.

Description

Technical Field

[0001] This invention relates to the field of agricultural machinery, and more specifically to a lifting device. Background Technology

[0002] The lifter, also known as the suspension lift device, is a core component on a tractor used to connect with agricultural implements. It is mainly used to raise and lower the implements. During field operations such as rotary tillage, plowing, and deep loosening, the soil resistance changes constantly. Sometimes, local obstacles such as stones, tree roots, and hard clods of soil may be encountered, causing significant fluctuations or even sudden increases in operating resistance.

[0003] Traditional small tractor lifts have relatively simple functions, mostly only having position adjustment capabilities or lacking comprehensive force and position adjustment functions. During operation, they have the following shortcomings: 1) When the implement encounters an obstacle or the resistance increases suddenly, the lift cannot sense the change in resistance and respond automatically. The sudden load is directly transmitted to the tractor body and transmission system through the suspension components, which can easily cause deformation of the implement, damage to the suspension components, or even damage to the main structure; 2) When relying solely on position adjustment, the working depth is determined by the position of the lifting arm and cannot be automatically fine-tuned according to soil resistance. When the resistance changes suddenly, the implement is easily dragged, which not only affects the consistency of tillage depth but also increases the stress on the equipment; 3) Some lifts use external hydraulic cylinders or separate control mechanisms, which result in dispersed components, occupy a large space, and are not conducive to the compact layout and protection of the entire machine.

[0004] Therefore, there is an urgent need for a lifting device that is compact in structure, can integrate force and position adjustment, and can automatically adjust in case of overload to protect agricultural machinery and main structure. Summary of the Invention

[0005] The primary technical problem solved by this invention is to achieve comprehensive force and position adjustment and stable lifting control of the lifting device.

[0006] To address the aforementioned problems, this invention provides a lifting device comprising a housing with two lifting arms, left and right, the rear ends of which can swing up and down to achieve lifting and lowering of the lifting device. The housing is equipped with a first driving device capable of driving the lifting arms to swing. The housing also includes a distributor main control valve for switching the lifting and lowering states of the lifting device. The distributor main control valve has a valve stem capable of sliding back and forth and has a lowering position, a neutral position, and a lifting position. A lever arm capable of swinging around a transverse axis is hinged to the front end of the valve stem, with the hinge located at the middle of the lever arm. An upper shift fork mechanism and a lower shift fork mechanism are rotatably mounted on the housing. The upper shift fork mechanism is connected to the upper end of the lever arm, and the lower shift fork mechanism is connected to the lower end of the lever arm. A first linkage mechanism located in a longitudinal vertical plane is provided between the lifting arms and the lower shift fork mechanism. The housing is equipped with a guide plate, on which a... The guide groove extends forward and backward. A swing connecting plate is provided on one side of the guide vertical plate. The middle part of the swing connecting plate extends into the guide groove through a horizontally arranged guide shaft. A second linkage mechanism located in the longitudinal vertical plane is provided between the lower end of the swing connecting plate and the upper shift fork mechanism. A position adjustment handle that can provide constraint to the second linkage mechanism is installed on the housing. A force adjustment handle is provided on the housing. A G-link is provided between the force adjustment handle and the middle part of the swing connecting plate. A swing support is provided at the rear end of the housing. The lower end of the swing support is hinged to the housing through a hinge shaft. A limiting mechanism for limiting the forward and backward swing amplitude of the upper end of the swing support is provided between the upper end of the swing support and the housing. The rear ends of the two lifting arms and the part of the swing support above the hinge portion together form a three-point suspension connection for connecting the machine tool. A third linkage mechanism is provided between the upper end of the swing support and the upper end of the swing connecting plate.

[0007] With the above structure, the main control valve of the distributor, lever arm, upper and lower shift fork mechanisms, first to third linkage mechanisms, force adjustment handle, position adjustment handle, and three-point suspension are integrated into one unit, using the housing as the mounting base. The valve stem is hinged in the middle of the lever arm, connected to the upper shift fork above and the lower shift fork below, so that the force and position control signal is input through the upper shift fork and the lifting arm position feedback is input through the lower shift fork. The two signals converge at the lever arm to drive the valve stem, providing a structural basis for comprehensive force and position adjustment. The overall structure is relatively compact.

[0008] Furthermore, the upper shift fork mechanism includes an upper horizontal shaft rotatably mounted on the housing, with an upper shift fork connected above the upper horizontal shaft. The upper end of the lever arm has an upper sliding groove extending along the lever arm, and the upper shift fork extends into the upper sliding groove. The lower shift fork mechanism includes a lower horizontal shaft rotatably mounted on the housing, with a lower shift fork connected below the lower horizontal shaft. The lower end of the lever arm has a lower sliding groove extending along the lever arm, and the lower shift fork extends into the lower sliding groove. The upper horizontal shaft extends into the sliding groove at the upper end of the lever arm via the upper shift fork, and the lower horizontal shaft extends into the sliding groove at the lower end of the lever arm via the lower shift fork, converting the rotation of the horizontal shaft into displacement drive for the upper and lower ends of the lever arm. The sliding groove structure allows the control end and the feedback end to independently rotate with the horizontal shaft and drive the lever arm to swing, ensuring that the transmission of force position signals and position feedback do not interfere with each other and that the summation is reliable.

[0009] Furthermore, the first linkage mechanism includes link A, link B, and link C; link A is fixedly connected to the lifting arm and extends downwards, the lower end of link A is hinged to the rear end of link B, the front end of link B extends upwards and is hinged to the rear end of link C, and the front end of link C extends downwards and is fixed relative to the lower horizontal axis. The first linkage mechanism transmits the actual position of the lifting arm to the lower horizontal axis, and then acts on the lower end of the lever arm via the lower shift fork, forming position feedback to the distributor's main control valve.

[0010] Furthermore, the second linkage mechanism includes link D, link E, and link F; the lower rear end of link D is hinged to the lower end of the swing connecting plate, the upper front end of link D is hinged to the front end of link E, the rear end of link E is hinged to the upper rear end of link F, and the lower front end of link F is fixed relative to the upper horizontal axis; a cam surface is provided on the front side of link F, and the position adjustment handle is hinged to the housing at its lower end via a transverse hinge axis, and its upper end can be mounted on the housing in a way that allows for angle adjustment within the longitudinal vertical plane. A protrusion is provided on the position adjustment handle, and the protrusion contacts the cam surface. The second linkage mechanism, through the contact between the cam surface on the front side of link F and the protrusion on the position adjustment handle, continuously converts the angle change of the handle into the position of the upper horizontal axis, thereby setting the target working depth. The cam surface is a continuous curved surface, and the handle can be positioned arbitrarily within its stroke, realizing stepless arbitrary depth adjustment of the position; the mechanical contact structure of the protrusion and the cam surface is simple, has no electrical dependence, and has high reliability.

[0011] Furthermore, the force adjustment handle is mounted on the housing in such a manner that its lower end is hinged to the housing via a transverse hinge axis, and its upper end is angle-adjustable in the longitudinal vertical plane; the rear end of the G-link is rotatably connected to the guide shaft, and the front end of the G-link is hinged to the force adjustment handle via a transverse hinge axis. The force adjustment handle is connected to the guide shaft via the G-link. By operating the force adjustment handle, the position of the guide shaft within the guide groove can be changed, i.e., the rotation center of the swing connecting plate can be changed, thereby setting the sensing reference for force adjustment, allowing the operator to preset the upper limit of the machine's force according to operational needs.

[0012] Furthermore, both lifting arms have high-position connection holes at their rear ends, and the swing support, located above the hinge, has multiple low-position connection holes spaced vertically. The two high-position connection holes, together with any of the low-position connection holes, form a three-point suspension system for connecting implements. The high-position connection holes at the rear ends of the lifting arms and the multiple low-position connection holes spaced vertically on the swing support, together form a three-point suspension. The multiple low-position connection holes can accommodate the attachment of different implements, improving the compatibility and attachment flexibility of the lifting device and agricultural machinery.

[0013] Furthermore, the third linkage mechanism includes a link H and a link I; the upper end of link H is hinged to the upper end of the swing support, the rear end of link I is hinged to the lower end of link H, and the front end of link I is hinged to the upper end of the swing connecting plate. The third linkage mechanism transmits the swing of the upper end of the swing support to the upper end of the swing connecting plate, converting the resistance transmitted from the machine into the rotation of the swing connecting plate, thus forming a force-adjusting sensing chain.

[0014] Furthermore, a transverse vertical plate is provided in the middle of the housing. The rear end of the J-link is hinged to the middle of the I-link, and the front end of the J-link passes through a clearance hole in the transverse vertical plate. A spring A is fitted on the J-link, and a limiting part is provided on the J-link. The front and rear ends of the spring A abut against the transverse vertical plate and the limiting part, respectively. A spring B is provided on the housing. The rear end of the spring B is connected to the housing, and the front end of the spring B is connected to the middle of the J-link. The J-link, spring A, and spring B on the transverse vertical plate constitute a buffer mechanism to ensure that each component operates within the preload range.

[0015] Furthermore, the swing support includes two swing plates, with a front side plate connected to the upper front side of the two swing plates; the housing is provided with a sleeve extending forward and backward, with a front sealing plate at the front end of the sleeve, a sliding limiting plate that can slide forward and backward installed inside the sleeve, and a C spring installed inside the sleeve, with the front and rear ends of the C spring abutting against the sliding limiting plate and the front side plate respectively; an adjusting bolt is installed on the front sealing plate, with the screw of the adjusting bolt abutting against the front side of the sliding limiting plate; the limiting mechanism includes an ear plate connected to the rear end of the housing and located between the two swing plates, with a limiting pin passing through the middle of the two swing plates, and a long limiting groove extending forward and backward on the ear plate, through which the limiting pin passes. The C spring inside the sleeve is preloaded by the adjusting bolt, constituting a force-adjusting trigger elastic element; the limiting pin of the limiting mechanism is installed in the long limiting groove of the ear plate, limiting the swing amplitude of the swing support and preventing excessive stroke.

[0016] Furthermore, the first driving device includes a horizontally arranged lifting arm shaft rotatably mounted on the housing, with two lifting arms spaced apart at both ends of the lifting arm shaft, and a downward-extending driving arm located in the middle of the lifting arm shaft. The first driving device also includes a hydraulic cylinder, which includes a cylinder barrel located on the housing in front of the driving arm and angled downwards from front to back. A piston is slidably mounted inside the cylinder barrel, and a piston rod angled downwards from front to back is provided between the piston and the driving arm. The rear end of the piston rod is hinged to the lower end of the driving arm in a manner that allows rotation around the horizontal axis, and the front end of the piston rod is hinged to the piston in a manner that allows rotation around the horizontal axis. The distributor main control valve is a hydraulic control valve used to control the piston of the hydraulic cylinder to slide within the cylinder barrel. A one-way valve that only allows oil to flow into the hydraulic cylinder is provided on the oil supply line of the hydraulic cylinder, and a lowering valve that is mechanically linked to the distributor main control valve is provided on the oil return line of the hydraulic cylinder. When the distributor main control valve is in the lowering position, the lowering valve connects to the oil return line of the hydraulic cylinder, and when the distributor main control valve is in the lifting position or neutral position, the lowering valve disconnects the oil return line of the hydraulic cylinder. The first drive unit uses a tilted single-acting cylinder to drive the lifting arm shaft. The distributor's main control valve serves as the hydraulic control valve for controlling the piston's sliding. The oil supply circuit is equipped with a check valve, and the oil return circuit is equipped with a lowering valve that is mechanically linked to the distributor's main control valve. When lifting to the neutral position, the lowering valve is disconnected, the oil cylinder is pressure-maintained by the check valve, and the machine is stably suspended. When lowering to the working position, the lowering valve is mechanically connected with the valve stem, the oil cylinder returns oil through the lowering valve, and the machine falls by its own weight.

[0017] In summary, the beneficial effects of this invention are as follows: 1. The overall design features a built-in lifting device, resulting in a simple and compact structure; 2. It combines force adjustment and position adjustment, allowing for integrated use during operation, resulting in high control precision and a wide range of applications; 3. In case of overload, the lifting arm automatically floats up to reduce the load, maximizing the protection of the agricultural machinery and main structure from damage; 4. The position adjustment utilizes a cam surface for stepless adjustment, allowing the implement to be freely adjusted at different depths at any time, facilitating operation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of an embodiment of the present invention; Figure 2 yes Figure 1 A perspective view of the embodiment shown; Figure 3 yes Figure 1 A cross-sectional view of the embodiment shown; Figure 4 yes Figure 1 A schematic diagram of the omitted structure; Figure 5 yes Figure 4 A schematic diagram of the omitted structure; Figure 6 yes Figure 1 The illustrated embodiment is a perspective view omitting structures such as the housing. Figure 7This is a schematic diagram of the hydraulic system that is used in conjunction with the lifter in this invention.

[0019] In the diagram: 1. Housing; 2. Lifting arm; 3. First drive unit; 4. Distributor main control valve; 5. Valve stem; 6. Lever arm; 7. Upper fork mechanism; 8. Upper fork; 9. Lower fork mechanism; 10. Lower fork; 11. First linkage mechanism; 12. Guide vertical plate; 13. Swing connecting plate; 14. Guide shaft; 15. Second linkage mechanism; 16. Position adjustment handle; 17. Force adjustment handle; 18. Linkage G; 19. Swing support; 20. Limiting mechanism; 21. Third linkage mechanism; 22. Upper horizontal shaft; 23. Upper slide groove; 24. Lower horizontal shaft; 25. Lower slide groove; 26. Linkage A; 27. Linkage B; 28. Linkage C; 29. ​​Linkage D 30. Linkage E, 31. Linkage F, 32. Cam surface, 33. Protruding post, 34. High-position connecting hole, 35. Low-position connecting hole, 36. Linkage H, 37. Linkage I, 38. Horizontal vertical plate, 39. Linkage J, 40. Spring A, 41. Limiting part, 42. Spring B, 43. Swing plate, 44. Front side plate, 45. Sleeve, 46. Front sealing plate, 47. Sliding limiting plate, 48. Spring C, 49. Adjusting bolt, 50. Ear plate, 51. Limiting pin, 52. Long limiting groove, 53. Lifting arm shaft, 54. Drive arm, 55. Cylinder, 56. Piston, 57. Piston rod, 58. Lowering valve, 59. Check valve, 60. Hydraulic cylinder. Detailed Implementation

[0020] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0021] Refer to the attached diagram, especially Figure 1 , Figure 2 , Figure 3 In some embodiments of the present invention, a housing 1 is included, on which two lifting arms 2 are provided, the front end of the lifting arm 2 is mounted on the housing 1 in a manner that allows it to rotate around a transverse axis, and the rear end of the lifting arm 2 is tilted upward and can swing up and down to realize the lifting of the lifting device. A first driving device 3 is provided on the housing 1 to drive the lifting arm 2 to swing. A distributor main control valve 4 is provided on the housing 1 for switching the lifting state of the lifting device. The distributor main control valve 4 has a valve stem 5 that can slide back and forth.

[0022] Refer to the attached diagram, especially Figure 1 , Figure 6 , Figure 7The distributor main control valve 4 has three stations arranged sequentially from front to back: a descending station, a neutral station, and a lifting station; the front end of the valve stem 5 is hinged to a lever arm 6 that can swing around the transverse axis, with the hinge located in the middle of the lever arm 6; an upper shift fork mechanism 7 and a lower shift fork mechanism 9 are rotatably mounted on the housing 1, spaced apart vertically, with the upper shift fork mechanism 7 connected to the upper end of the lever arm 6 and the lower shift fork mechanism 9 connected to the lower end of the lever arm 6.

[0023] The upper fork mechanism 7 includes an upper horizontal shaft 22 rotatably mounted on the housing 1, with an upper fork 8 connected above the upper horizontal shaft 22. The upper end of the lever arm 6 has an upper sliding groove 23 extending along the lever arm 6, and the upper fork 8 extends into the upper sliding groove 23. The lower fork mechanism 9 includes a lower horizontal shaft 24 rotatably mounted on the housing 1, with a lower fork 10 connected below the lower horizontal shaft 24. The lower end of the lever arm 6 has a lower sliding groove 25 extending along the lever arm 6, and the lower fork 10 extends into the lower sliding groove 25. The upper horizontal shaft 22 extends into the sliding groove at the upper end of the lever arm 6 via the upper fork 8, and the lower horizontal shaft 24 extends into the sliding groove at the lower end of the lever arm 6 via the lower fork 10, converting the rotation of the horizontal shaft into displacement drive for the upper and lower ends of the lever arm 6.

[0024] Refer to the attached diagram, especially Figure 1 , Figure 2 , Figure 6 A first linkage mechanism 11 located in the longitudinal vertical plane is provided between the lifting arm 2 and the lower fork mechanism 9; a guide vertical plate 12 is provided on the housing 1, and a guide groove extending forward and backward is provided on the side of the guide vertical plate 12. A swing connecting plate 13 is provided on one side of the guide vertical plate 12, and the middle part of the swing connecting plate 13 extends into the guide groove through a guide shaft 14 arranged laterally, so that the swing connecting plate 13 can rotate relative to the guide vertical plate 12 around the transverse axis and slide forward and backward along the guide groove.

[0025] The first linkage mechanism 11 includes a link A 26, a link B 27, and a link C 28. Link A 26 is fixedly connected to the lifting arm 2 and extends downward. The lower end of link A 26 is hinged to the rear end of link B 27. The front end of link B 27 extends upward and is hinged to the rear end of link C 28. The front end of link C 28 extends downward and is fixed relative to the lower horizontal axis 24.

[0026] Refer to the attached diagram, especially Figure 2 , Figure 4 , Figure 6 A second linkage mechanism 15 located in the longitudinal vertical plane is provided between the lower end of the swing connecting plate 13 and the upper shift fork mechanism 7. A position adjustment handle 16 that can provide constraint to the second linkage mechanism 15 is installed on the housing 1.

[0027] The second linkage mechanism 15 includes a D-link 29, an E-link 30, and an F-link 31. The lower rear end of the D-link 29 is hinged to the lower end of the swing connecting plate 13, the upper front end of the D-link 29 is hinged to the front end of the E-link 30, the rear end of the E-link 30 is hinged to the upper rear end of the F-link 31, and the lower front end of the F-link 31 is fixed relative to the upper horizontal axis 22. The front side of the F-link 31 is provided with a cam surface 32. The position adjustment handle 16 is mounted on the housing 1 in such a way that its lower end is hinged to the housing 1 through a transverse hinge axis and its upper end can be angled in the longitudinal vertical plane. The position adjustment handle 16 is provided with a protrusion 33, which contacts the cam surface 32. The mounting method of the position adjustment handle 16 on the housing 1 is the prior art. For example, the lower end of the position adjustment handle 16 is hinged to the housing 1 via a transverse hinge shaft. Multiple disc-shaped spring washers are fitted at the hinge shaft and axially pressed by a nut, so that the position adjustment handle 16 and the housing 1 form a frictional constant force between the hinge surface. To move the position adjustment handle 16, this frictional force must be overcome before it can rotate around the hinge shaft in the longitudinal vertical plane. After the external force is removed, it is held by the frictional force, so that the position adjustment handle 16 can stay arbitrarily in the fan-shaped plane.

[0028] Refer to the attached diagram, especially Figure 5 , Figure 6 The housing 1 is equipped with a force adjustment handle 17, and a G-link 18 is provided between the force adjustment handle 17 and the middle of the swing connecting plate 13. The force adjustment handle 17 is mounted on the housing 1 with its lower end hinged to the housing 1 via a transverse hinge axis and its upper end adjustable in the longitudinal vertical plane. The rear end of the G-link 18 is rotatably connected to the guide shaft 14 via a transverse rotation shaft, and the front end of the G-link 18 is hinged to the force adjustment handle 17 via a transverse hinge axis. The installation method of the force adjustment handle 17 on the housing 1 is existing technology. For example, the lower end of the force adjustment handle 17 is hinged to the housing 1 via a transverse hinge axis. Multiple disc spring washers are fitted at the hinge axis and axially pressed by a nut, so that the force adjustment handle 17 and the housing 1 form a frictional constant force between the hinge surface. The force adjustment handle 17 needs to overcome this frictional force to rotate around the hinge axis in the longitudinal vertical plane. After the external force is removed, it is held by the frictional force, so that the force adjustment handle 17 can stop arbitrarily in the sector plane.

[0029] Refer to the attached diagram, especially Figure 2 , Figure 3 , Figure 5The rear end of the housing 1 is provided with a swing support 19. The lower end of the swing support 19 is hinged to the housing 1 via a hinge shaft. The upper end of the swing support 19 is provided with a limiting mechanism 20 between itself and the housing 1 to limit the forward and backward swing amplitude of the upper end of the swing support 19. The rear ends of the two lifting arms 2 and the part of the swing support 19 located above the hinge portion together form a three-point suspension fit for connecting the machine. The rear ends of the two lifting arms 2 are each provided with a high-position connection hole 34. The part of the swing support 19 located above the hinge portion is provided with multiple low-position connection holes 35 spaced vertically. The two high-position connection holes 34 and any low-position connection holes 35 together form a three-point suspension fit for connecting the machine.

[0030] Refer to the attached diagram, especially Figure 5 , Figure 6 A third linkage mechanism 21 is provided between the upper end of the swing support 19 and the upper end of the swing connecting plate 13. The third linkage mechanism 21 includes an H-link 36 and an I-link 37; the upper end of the H-link 36 is hinged to the upper end of the swing support 19, the rear end of the I-link 37 is hinged to the lower end of the H-link 36, and the front end of the I-link 37 is hinged to the upper end of the swing connecting plate 13.

[0031] A transverse vertical plate 38 is provided in the middle of the housing 1. The rear end of the J link 39 is hinged to the middle of the I link 37. The front end of the J link 39 passes through the clearance hole on the transverse vertical plate 38. An A spring 40 is fitted on the J link 39. A limiting part 41 is provided on the J link 39. The front and rear ends of the A spring 40 abut against the transverse vertical plate 38 and the limiting part 41, respectively. A B spring 42 is provided on the housing 1. The rear end of the B spring 42 is connected to the housing 1, and the front end of the B spring 42 is connected to the middle of the J link 39.

[0032] Refer to the attached diagram, especially Figure 2 , Figure 3 In some embodiments of the present invention, the swing support 19 includes two swing plates 43, and a front side plate 44 is connected to the upper front side of the two swing plates 43; the housing 1 is provided with a sleeve 45 extending back and forth, the front end of the sleeve 45 is provided with a front sealing plate 46, a sliding limiting plate 47 that can slide back and forth is installed inside the sleeve 45, a C spring 48 is installed inside the sleeve 45, the front and rear ends of the C spring 48 respectively abut against the sliding limiting plate 47 and the front side plate 44, an adjusting bolt 49 is installed on the front sealing plate 46, and the screw of the adjusting bolt 49 abuts against the front side of the sliding limiting plate 47; the limiting mechanism 20 includes an ear plate 50 connected to the rear end of the housing 1 and located between the two swing plates 43, a limiting pin 51 is inserted through the middle of the two swing plates 43, and a long limiting groove 52 extending back and forth is provided on the ear plate 50, through which the limiting pin 51 passes.

[0033] Further, the first drive device 3 comprises a transversely arranged lift arm shaft 53 rotatably mounted on the housing 1, two lift arms 2 are arranged at intervals left and right at both ends of the lift arm shaft 53, the middle part of the lift arm shaft 53 is provided with a downward extending drive arm 54, the first drive device 3 further comprises an oil cylinder 60, the oil cylinder 60 comprises a cylinder barrel 55 which is arranged on the housing 1 at a position in front of the drive arm 54 and is arranged obliquely with the front part higher than the rear part, a piston 56 is slidably mounted in the cylinder barrel 55, a piston rod 57 arranged obliquely with the front part higher than the rear part is arranged between the piston 56 and the drive arm 54, the rear end of the piston rod 57 is hinged to the lower end of the drive arm 54 in a manner capable of rotating around a transverse axis, and the front end of the piston rod 57 is hinged to the piston 56 in a manner capable of rotating around a transverse axis; the main control valve 4 of the distributor is a hydraulic control valve for controlling the sliding of the piston 56 of the oil cylinder 60 in the cylinder barrel 55.

[0034] With reference to the accompanying drawings, in particular Figure 7 , the oil supply path of the oil cylinder 60 is provided with a one-way valve 59 that only allows oil to flow toward the oil cylinder 60, the oil return path of the oil cylinder 60 is provided with a lowering valve 58 that is mechanically linked with the main control valve 4 of the distributor, when the main control valve 4 of the distributor is in the lowering station, the lowering valve 58 communicates the oil return path of the oil cylinder 60, and when the main control valve 4 of the distributor is in the lifting station or the neutral station, the lowering valve 58 disconnects the oil return path of the oil cylinder 60.

[0035] As shown in Figure 7 , the hydraulic system matched with the lifter is formed by connecting a hydraulic pump, the main control valve 4 of the distributor, the oil cylinder 60, the one-way valve 59, the lowering valve 58 and an oil tank through oil paths, the pressure oil output by the hydraulic pump supplies oil to the oil cylinder 60 through the main control valve 4 of the distributor, the piston rod 57 of the oil cylinder 60 is hinged with the drive arm 54 in the mechanical structure of the lifter to convert hydraulic energy into the swing of the lift arm 2, the oil supply path is provided with the one-way valve 59 to ensure that the oil cylinder is locked and maintains pressure at the neutral station, and the oil return path is provided with the lowering valve 58 linked with the valve rod 5 of the main control valve of the distributor to control the oil return during lowering.

[0036] The mechanical structure of this lifter cooperates with the matched hydraulic system through the following hydraulic interfaces to realize the lifting, position maintaining and lowering of the implement: 1) The main control valve 4 of the distributor is a hydraulic control valve, whose valve rod 5 switches among the three stations of lowering, neutral and lifting under mechanical operation to control the extension and retraction of the piston 56 of the oil cylinder 60, Figure 1 , Figure 3 , Figure 6The diagram shows the installation position and connection relationship of the distributor main control valve 4 and the oil cylinder 60 on the housing 1; 2) When the valve stem 5 of the distributor main control valve is switched to the lowering position, it is linked with the valve core of the lowering valve 58, so that the lowering valve 58 is connected to the return oil circuit, and the oil inlet chamber of the oil cylinder 60 is connected to the oil tank through the lowering valve 58. Under the action of its own weight, the tool and the lifting arm 2 swing down with the piston 56 retracting. When the distributor main control valve 4 is in the lifting or neutral position, this linkage structure causes the lowering valve 58 to disconnect the return oil circuit and the oil inlet chamber of the oil cylinder to be closed; 3) A one-way valve 59 is provided on the oil supply line of the oil cylinder 60, which only allows the oil to flow from the distributor main control valve 4 to the first driving device and cuts off the flow in the reverse direction. When the distributor main control valve 4 is in the neutral position, the one-way valve 59 locks the oil inlet chamber of the oil cylinder 60, so that the tool is kept at the current height and does not sink.

[0037] The working principle of this invention is as follows: 1. Lifting operation and three-position switching The distributor's main control valve 4 has a valve stem 5 that can slide back and forth. From front to back, the valve stem 5 has three positions: a lowering position, a neutral position, and a lifting position. A lever arm 6 is hinged to the front end of the valve stem 5, with the hinge point located in the middle of the lever arm 6. The upper end of the lever arm 6 is connected to the upper shift fork mechanism 7, and the lower end is connected to the lower shift fork mechanism 9. The lever arm 6 constitutes a summing element for control signals and feedback signals: the upper shift fork mechanism 7 inputs position adjustment and force adjustment control signals to the upper end of the lever arm 6, and the lower shift fork mechanism 9 inputs feedback signals of the actual position of the lifting arm 2 to the lower end of the lever arm 6. The displacement of the valve stem 5 is determined by the difference between the two signals. When valve stem 5 is pushed away from the neutral position, the distributor main control valve 4 switches to either the lifting or lowering position: In the lifting position, oil enters the cylinder 60 of the first drive device 3, and the piston rod 57 extends, driving the lifting arm shaft 53 to rotate, causing the two lifting arms 2 to swing upward around their front rotation axis, thus lifting the machine; in the lowering position, oil returns from the cylinder, and the lifting arms 2 swing downward under the weight of the machine, thus lowering the machine. When the control signal and feedback signal tend to be balanced, valve stem 5 returns to the neutral position, and the lifting arms 2 remain at their current height.

[0038] 2. Position Adjustment Working Process The position adjustment handle 16 is used to set the target working depth of the machine. The upper end of the position adjustment handle 16 is angle-adjustable in the longitudinal vertical plane. The protrusion 33 on it abuts against the cam surface 32 on the front side of the F-link 31. The angle change of the position adjustment handle 16 is converted into the position change of the F-link 31 and the upper horizontal shaft 22 through the cam surface 32, thereby setting the reference position of the second linkage mechanism 15. When the position adjustment handle 16 is moved to change the target depth, the upper horizontal shaft 22 rotates accordingly, pushing the upper end of the lever arm 6 through the upper shift fork 8. The lever arm 6 swings around the central hinge point and drives the valve stem 5 away from the neutral working position. The distributor main control valve 4 switches to the lifting position or the lowering position, and the first drive device 3 drives the lifting arm 2 to rise and fall. The actual position of the lifting arm 2 is transmitted to the lower horizontal shaft 24 through the first linkage mechanism 11, and then acts on the lower end of the lever arm 6 through the lower shift fork 10, forming feedback opposite to the control signal. As the lifting arm 2 approaches the target height, the feedback signal gradually cancels out the control signal, the lever arm 6 swings back, the valve stem 5 returns to the neutral position, and the lifting arm 2 stops and remains at the set depth. Since the cam surface 32 is a continuous curved surface, the position adjustment handle 16 can be positioned arbitrarily within its stroke, realizing stepless adjustment of the machine's working depth.

[0039] 3. Force adjustment working process The force adjustment handle 17 is used to set the working resistance reference of the tool. When the tool is working, the resistance acts on the lower connecting hole 35 of the swing support 19, pushing the swing support 19 to swing around its lower hinge axis; the swing of the swing support 19 is transmitted to the upper end of the swing connecting plate 13 through the third linkage mechanism 21, causing the swing connecting plate 13 to swing around the guide shaft 14. The lower end of the swing connecting plate 13 drives the upper horizontal shaft 22 to rotate through the second linkage mechanism 15, and then drives the valve stem 5 through the upper shift fork 8 and the lever arm 6, realizing the transmission of the resistance signal to the distributor main control valve 4. The lower end of the force adjustment handle 17 is hinged to the housing 1, and the upper end angle is adjustable. The G-link 18 connects the force adjustment handle 17 and the guide shaft 14. Turning the force adjustment handle 17 can change the position of the guide shaft 14 in the guide groove, that is, change the rotation center of the swing connecting plate 13, thereby setting the trigger resistance value of the force adjustment. When the resistance of the implement exceeds the set value, the force sensor signal causes the valve stem 5 to switch to the lifting position, and the lifting arm 2 drives the implement to float up, reducing the soil penetration depth, and the working resistance decreases accordingly.

[0040] 4. Automatic buoyancy control in case of overload The force-adjusting sensing elastic element is a C-spring 48: a sleeve 45 is fixed to the housing 1, and the two ends of the C-spring 48 inside the sleeve 45 abut against the sliding limit plate 47 and the front side plate 44, respectively. The adjusting bolt 49 on the front sealing plate 46 abuts against the sliding limit plate 47. Rotating the adjusting bolt 49 can change the preload of the C-spring 48. During normal operation, the machine resistance is within the preload range of the C-spring 48, and the swing support 19 swings only slightly. When the implement encounters obstacles such as rocks, the resistance suddenly increases and exceeds the preload of spring C 48. The swing support 19 swings significantly, causing the I link 37 of the third linkage mechanism 21 to move in the front-back direction. At this time, the J link 39 overcomes the force of spring A 40, and the I link 37 overcomes the force of spring B 42. The front end of the J link 39 acts on the upper end of the swing connecting plate 13. After the linkage of the second linkage mechanism 15 and the upper shift fork mechanism 7, the drive valve rod 5 switches to the lifting position, and the lifting arm 2 automatically floats up to reduce the load and avoid damage to the agricultural implement and the main structure.

[0041] 5. Comprehensive adjustment of force and position Both the position adjustment signal and the force adjustment signal act on the upper end of the lever arm 6 via the upper horizontal shaft 22 and the upper shift fork 8. The position feedback of the lifting arm 2 acts on the lower end of the lever arm 6 via the lower horizontal shaft 24 and the lower shift fork 10. The lever arm 6 acts as a common summing element, superimposing all signals to drive the valve stem 5. Therefore, this lifting device can simultaneously respond to changes in working depth and working resistance, realizing the integrated use of force adjustment and position adjustment.

[0042] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be considered within the scope of protection of the present invention.

Claims

1. A lifting device, comprising a housing (1), wherein the housing (1) is provided with two lifting arms (2) on the left and right sides, the rear ends of the lifting arms (2) being able to swing up and down to achieve lifting and lowering of the lifting device, and the housing (1) being provided with a first driving device (3) capable of driving the lifting arms (2) to swing, characterized in that: The housing (1) is provided with a distributor main control valve (4) for switching the lifting state of the elevator. The distributor main control valve (4) has a valve stem (5) that can slide back and forth. The distributor main control valve (4) has a lowering position, a neutral position and a lifting position. The valve stem (5) is hinged to a lever arm (6) that can swing around a transverse axis, with the hinge located in the middle of the lever arm (6); an upper shift fork mechanism (7) and a lower shift fork mechanism (9) are rotatably mounted on the housing (1), with the upper shift fork mechanism (7) connected to the upper end of the lever arm (6) and the lower shift fork mechanism (9) connected to the lower end of the lever arm (6); A first linkage mechanism (11) located in the longitudinal vertical plane is provided between the lifting arm (2) and the lower fork mechanism (9). The housing (1) is provided with a guide vertical plate (12), the guide vertical plate (12) is provided with a guide groove extending forward and backward, and a swing connecting plate (13) is provided on one side of the guide vertical plate (12). The middle part of the swing connecting plate (13) extends into the guide groove through a guide shaft (14) arranged laterally. A second linkage mechanism (15) located in the longitudinal vertical plane is provided between the lower end of the swing connecting plate (13) and the upper fork mechanism (7). A position adjustment handle (16) that can provide constraint to the second linkage mechanism (15) is installed on the housing (1). The housing (1) is provided with a force adjustment handle (17), and a G-link (18) is provided between the force adjustment handle (17) and the middle of the swing connecting plate (13). The rear end of the housing (1) is provided with a swing support (19). The lower end of the swing support (19) is hinged to the housing (1) through a hinge shaft. The upper end of the swing support (19) and the housing (1) are provided with a limiting mechanism (20) for limiting the swing amplitude of the upper end of the swing support (19). The rear ends of the two lifting arms (2) and the part of the swing support (19) located above the hinge part together constitute a three-point suspension fit for connecting the machine tool. A third linkage mechanism (21) is provided between the upper end of the swing support (19) and the upper end of the swing connecting plate (13).

2. The lifting device according to claim 1, characterized in that: The upper shift fork mechanism (7) includes an upper horizontal shaft (22) rotatably mounted on the housing (1), the upper horizontal shaft (22) is connected to an upper shift fork (8) located above the upper horizontal shaft (22), the upper end of the lever arm (6) is provided with an upper sliding groove (23) extending along the lever arm (6), and the upper shift fork (8) extends into the upper sliding groove (23); the lower shift fork mechanism (9) includes a lower horizontal shaft (24) rotatably mounted on the housing (1), the lower horizontal shaft (24) is connected to a lower shift fork (10) located below the lower horizontal shaft (24), the lower end of the lever arm (6) is provided with a lower sliding groove (25) extending along the lever arm (6), and the lower shift fork (10) extends into the lower sliding groove (25).

3. The lifting device according to claim 2, characterized in that: The first linkage mechanism (11) includes link A (26), link B (27) and link C (28); link A (26) is fixedly connected to the lifting arm (2) and extends downward. The lower end of link A (26) is hinged to the rear end of link B (27). The front end of link B (27) extends upward and is hinged to the rear end of link C (28). The front end of link C (28) extends downward and is fixed relative to the lower horizontal axis (24).

4. The lifting device according to claim 2, characterized in that: The second linkage mechanism (15) includes a D-link (29), an E-link (30), and an F-link (31). The lower rear end of the D-link (29) is hinged to the lower end of the swing connecting plate (13), the upper front end of the D-link (29) is hinged to the front end of the E-link (30), the rear end of the E-link (30) is hinged to the upper rear end of the F-link (31), and the lower front end of the F-link (31) is fixed relative to the upper horizontal axis (22). The front side of the F-link (31) is provided with a cam surface (32). The lower end of the position adjustment handle (16) is hinged to the housing (1) through a transverse hinge axis, and the upper end can be installed on the housing (1) in a way that the angle is adjustable in the longitudinal vertical plane. The position adjustment handle (16) is provided with a protrusion (33), which contacts the cam surface (32).

5. The lifter according to claim 1, characterized in that: The force adjustment handle (17) is mounted on the housing (1) with its lower end hinged to the housing (1) via a transverse hinge axis and its upper end adjustable in the longitudinal vertical plane; the rear end of the G-link (18) is rotatably connected to the guide shaft (14), and the front end of the G-link (18) is hinged to the force adjustment handle (17) via a transverse hinge axis.

6. The lifter according to claim 1, characterized in that: The rear ends of both lifting arms (2) are provided with high-position connection holes (34), and the swing support (19) is provided with multiple low-position connection holes (35) spaced vertically above the hinge. The two high-position connection holes (34) together with any low-position connection hole (35) constitute a three-point suspension fit for connecting the machine tool.

7. The lifting device according to claim 1, characterized in that: The third linkage mechanism (21) includes H-link (36) and I-link (37); the upper end of H-link (36) is hinged to the upper end of the swing support (19), the rear end of I-link (37) is hinged to the lower end of H-link (36), and the front end of I-link (37) is hinged to the upper end of the swing connecting plate (13).

8. The lifter according to claim 7, characterized in that: A transverse vertical plate (38) is provided in the middle of the housing (1). The rear end of the J link (39) is hinged in the middle of the I link (37). The front end of the J link (39) passes through the clearance hole on the transverse vertical plate (38). An A spring (40) is fitted on the J link (39). A limiting part (41) is provided on the J link (39). The front and rear ends of the A spring (40) abut against the transverse vertical plate (38) and the limiting part (41) respectively. A B spring (42) is provided on the housing (1). The rear end of the B spring (42) is connected to the housing (1). The front end of the B spring (42) is connected to the middle of the J link (39).

9. The lifting device according to claim 1, characterized in that: The swing support (19) includes two swing plates (43), and a front side plate (44) is connected to the upper front side of the two swing plates (43); a sleeve (45) extending forward and backward is provided on the housing (1), a front sealing plate (46) is provided at the front end of the sleeve (45), a sliding limiting plate (47) that can slide forward and backward is installed inside the sleeve (45), a C spring (48) is installed inside the sleeve (45), and the front and rear ends of the C spring (48) abut against the sliding limiting plate (47) and the front side plate (44) respectively. On 44), an adjusting bolt (49) is installed on the front sealing plate (46), and the screw of the adjusting bolt (49) rests against the front side of the sliding limit plate (47); the limiting mechanism (20) includes an ear plate (50) connected to the rear end of the housing (1) and located between the two swing plates (43), a limiting pin (51) is installed in the middle of the two swing plates (43), and the ear plate (50) is provided with a long limiting groove (52) extending forward and backward, and the limiting pin (51) passes through the long limiting groove (52).

10. The lifter according to any one of claims 1 to 9, characterized in that: The first drive device (3) includes a lifting arm shaft (53) rotatably mounted on the housing (1) and arranged laterally. Two lifting arms (2) are spaced apart at both ends of the lifting arm shaft (53). A drive arm (54) extending downward is provided in the middle of the lifting arm shaft (53). The first drive device (3) also includes a hydraulic cylinder (60). The hydraulic cylinder (60) includes a cylinder barrel (55) located on the housing (1) in front of the drive arm (54) and arranged obliquely with a higher front and lower rear. A piston (56) is slidably mounted inside the cylinder barrel (55). A piston rod (57) arranged obliquely with a higher front and lower rear is provided between the piston (56) and the drive arm (54). The rear end of the piston rod (57) is hinged to the drive arm in a manner that allows it to rotate around the transverse axis. The lower end of the boom (54) and the front end of the piston rod (57) are hinged to the piston (56) in a manner that allows rotation around the transverse axis; the distributor main control valve (4) is a hydraulic control valve used to control the piston (56) of the oil cylinder (60) to slide in the cylinder barrel (55); the oil supply line of the oil cylinder (60) is provided with a one-way valve (59) that only allows oil to flow to the oil cylinder (60), and the oil return line of the oil cylinder (60) is provided with a lowering valve (58) that is mechanically linked with the distributor main control valve (4). When the distributor main control valve (4) is in the lowering position, the lowering valve (58) connects the oil return line of the oil cylinder (60), and when the distributor main control valve (4) is in the lifting position or the neutral position, the lowering valve (58) disconnects the oil return line of the oil cylinder (60).

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