Scissor lift equipment with hydraulic buffer for maintenance and control method

Abstract

The present invention relates to the technical field of scissor-type lifting equipment, and specifically to a scissor-type lifting equipment with a hydraulic buffer for maintenance and a control method. The scissor-type lifting equipment includes a hydraulic buffer and a scissor mechanism. The hydraulic buffer includes a hydraulic cylinder and a piston rod. The hydraulic cylinder has a lower connecting end, and the piston rod has an upper connecting end. The hydraulic buffer can support the scissor mechanism after being engaged with the scissor mechanism through the upper connecting end and the lower connecting end. Utilizing the characteristics of the hydraulic buffer itself with strong buffering capacity and strong load capacity, the hydraulic buffer is not only safe and stable when supporting the scissor mechanism, but also uses buffering performance to resist impact, avoiding damage to itself and the scissor mechanism. In addition, the maximum load value that can be met is relatively large. In actual maintenance, only the hydraulic buffer can be used for support, and there is no need to start the lifting mechanism to provide additional support force. In the maintenance process that generally takes a long time, this can effectively save energy.

Description

Technical Field

[0001] The invention relates to the technical field of scissor-type lifting equipment, and in particular to a scissor-type lifting equipment with a hydraulic buffer for maintenance and a control method. Background Art

[0002] Aerial work platforms are products that serve various industries for high-altitude work, equipment inspection, maintenance and other mobile high-altitude work. When working on an aerial work platform, workers need to stand on the platform above, so the platform needs to be safe enough, otherwise the workers may fall. In order to maintain the safety of the work platform, the work platform needs to be inspected and maintained frequently. During the inspection, the aerial platform needs to be raised, and the maintenance personnel perform inspections at the bottom of the platform. If the oil cylinder supporting the platform leaks oil or other faults occur, the platform falls down, and the maintenance personnel below will be in danger.

[0003] In order to solve the above problems, the applicant has previously conducted research and development and applied for a patent with the publication number CN103382012A. A scissor lift platform with maintenance protection device includes a base, a scissor lift assembly is arranged on the base, a fixed platform is arranged on the upper end of the scissor lift assembly, a mobile platform is arranged on the fixed platform, and the scissor device includes multiple layers of scissor units, each layer of scissor units is hinged to each other through a scissor shaft, and each layer of scissor shaft is movably connected with a maintenance support frame, one end of the maintenance support frame is connected to the scissor shaft and can rotate around the scissor shaft, and the other end of the maintenance support frame is Y-shaped for supporting the scissor shaft of the adjacent layer. When the scissor lift platform in the patent is maintained, the lifting assembly is first used to lift the scissor unit, and then the maintenance support frame of the scissor shaft is rotated to support the scissor shaft of the adjacent layer with its Y-shaped end. In this way, if a fault occurs, the maintenance support frame can also support the scissor unit, which plays a protective role for the maintenance personnel. However, the maintenance support frame in this patent is a purely rigid part, which has no buffering performance and is easily damaged when impacted by external force. Moreover, the fit between the maintenance support frame and the scissor shaft is not firm enough, the lower end is rotatable, which is not stable enough, and the upper end is Y-shaped, which is easy to separate from the scissor shaft, which may cause danger. Summary of the invention

[0004] The present invention makes improvements to the problems existing in the above-mentioned prior art, that is, the technical problem to be solved by the present invention is to provide a scissor-type lifting equipment with a hydraulic buffer for maintenance, including a hydraulic buffer and a scissor-type mechanism, the hydraulic buffer includes a hydraulic cylinder and a piston rod, the hydraulic cylinder has a lower connecting end, the piston rod has an upper connecting end, and the hydraulic buffer can support the scissor-type mechanism after being engaged with the scissor-type mechanism through the upper connecting end and the lower connecting end.

[0005] Preferably, the hydraulic buffer further includes a dust cover sleeved on one end of the hydraulic cylinder. The dust cover is fixed on the piston rod and can move relative to the hydraulic cylinder following the piston rod.

[0006] Preferably, warning scales are provided on the outer wall of the hydraulic cylinder. When the dust cover moves, a visible distance change occurs between the lower edge of the dust cover and the warning scales. When the lower edge of the dust cover reaches the warning scales, the hydraulic buffer reaches its maximum load capacity.

[0007] Preferably, it further includes a lifting mechanism, a controller, and a switch. The lifting mechanism supports the scissor mechanism and has a rising function module and a lowering function module capable of pushing the scissor mechanism to extend or contract. The switch is provided on the hydraulic buffer. When the lower edge of the dust cover reaches the warning scales, the switch can be triggered. The controller can receive the signal from the switch and can control the lifting mechanism to stop the lowering action.

[0008] Preferably, the scissor mechanism has horizontal support rods arranged vertically on both the left and right sides. The hydraulic buffer joints and supports two adjacent horizontal support rods located on the same side in the vertical direction.

[0009] Preferably, the scissor mechanism further includes two sets of scissor frames, front and back. The horizontal support rods are mounted between the two sets of scissor frames. The lower connection end can rotate relative to the horizontal support rod it joints. An open-up storage box is provided on the side wall of one scissor frame facing the other scissor frame. The hydraulic buffer can rotate through the lower connection end and fall into the storage box.

[0010] A control method for a scissor lift device with a hydraulic buffer for maintenance includes the following steps:

[0011] S01: Start the rising function module of the lifting mechanism to drive the scissor mechanism to extend until the distance between two adjacent horizontal support rods in the vertical direction exceeds the total length of the hydraulic buffer in the initial state;

[0012] S02: Take out the hydraulic buffer from the storage position and support it upward so that the upper connection end of the hydraulic buffer aligns with the horizontal support rod of the scissor mechanism;

[0013] S03: Start the lowering function module of the lifting mechanism to drive the scissor mechanism to contract. The horizontal support rod located above the hydraulic buffer and closest to the upper connection end moves towards the upper connection end until it joints with the upper connection end;

[0014] S04: the lifting mechanism continues to drive the scissor mechanism to contract, the cross support rod squeezes the hydraulic buffer, the hydraulic buffer gradually contracts, and the lower edge of the dust cover gradually approaches the warning scale;

[0015] S05: Before the lower edge of the dust cover exceeds the warning scale, the descending function module of the lifting mechanism is turned off to stop the contraction of the scissor mechanism, and the hydraulic buffer supports the scissor mechanism.

[0016] As a preferred embodiment of the present invention, when the lower edge of the dust cover reaches the warning scale in step S05, the dust cover triggers the switch, and the controller controls the lifting mechanism to close the descending function module after receiving the signal from the switch.

[0017] As a preferred embodiment of the present invention, the following steps are further performed after step S05:

[0018] S06: After the descending function module of the lifting mechanism is turned off, the controller controls the lifting mechanism to start the ascending function module, and the supporting force output by the ascending function module can maintain the static state of the scissor mechanism together with the hydraulic buffer.

[0019] A control method for a scissor lift with a hydraulic buffer for maintenance, comprising the following steps:

[0020] S01: Pull the scissor mechanism upward to extend the scissor mechanism until the distance between two adjacent horizontal support rods in the vertical direction exceeds the total length of the hydraulic buffer in the initial state;

[0021] S02: taking out the hydraulic buffer from the storage position and propping it upward, so that the upper connecting end of the hydraulic buffer is aligned with the horizontal support rod of the scissor mechanism;

[0022] S03: Keep pulling the scissor mechanism, and gradually lower the scissor mechanism downward by using the pulling force, so that the scissor mechanism contracts, and the cross support rod located above the hydraulic buffer and closest to the upper connecting end moves toward the upper connecting end until it is engaged with the upper connecting end;

[0023] S04: As the scissor mechanism continues to contract, the hydraulic buffer gradually supports the tie rod;

[0024] S05: Remove the lifting force so that the scissor mechanism is fully supported by the hydraulic buffer.

[0025] Beneficial effects:

[0026] Taking advantage of the strong buffering and load-bearing capabilities of the hydraulic buffer itself, the hydraulic buffer is not only safe and stable when supporting the scissor mechanism, but also uses its buffering performance to resist impact, avoiding damage to itself and the scissor mechanism. In addition, the maximum load value that can be met is relatively large. In actual maintenance, only the hydraulic buffer can be used for support, and there is no need to start the lifting mechanism to provide additional supporting force. This can effectively save energy during the generally long maintenance process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a schematic diagram of the overall structure of the scissor-type lifting device;

[0028] Figure 2 is a schematic diagram of the hydraulic buffer when it is working;

[0029] Figure 3 is a structural schematic diagram of the hydraulic buffer;

[0030] Figure 4 is a schematic diagram of the lower connecting end;

[0031] Figure 5 is a schematic diagram of the upper connecting end;

[0032] Figure 6 It is a schematic diagram of the three-dimensional structure in which the transmission nut mechanism and the safety nut mechanism are installed on the central screw;

[0033] Figure 7 It is a schematic diagram of the safety nut seat and the center screw;

[0034] Figure 8 for Figure 1 A cross-sectional view of

[0035] Fig. 9 for Figure 3 The schematic diagram of the plunger and the elastic buffer is omitted;

[0036] Fig.10 The schematic diagram of the outlet of the limiting channel being located on the top thread of the screw;

[0037] Fig.11 It is a schematic diagram that outlets of all the limiting channels are arranged on the spiral top teeth along the spiral extension direction of the spiral top teeth;

[0038] Fig.12 is a flow chart of a fault detection method;

[0039] In the figure: 1, center screw, 11, spiral raceway, 2, transmission nut mechanism, 3, safety nut mechanism, 31, safety nut seat, 32, limit hole, 33, elastic buffer, 34, safety ball, 35, spiral top tooth, 36, plunger, 37, transfer hole, 38, oil replenishing chamber; 4, scissor mechanism, 41, cross support rod, 42, scissor frame, 5, hydraulic buffer, 51, hydraulic cylinder, 52, piston rod, 53, dust cover, 6, lower connecting end, 61, lower arc seat, 62, lower arc groove, 63, lower opening and closing part, 64, mounting plate, 7, upper connecting end, 71, upper arc seat, 72, upper arc groove, 73, upper opening and closing part, 81, lower fastener, 82, upper fastener, 9, lifting mechanism. DETAILED DESCRIPTION

[0040] The following specific embodiments are merely explanations of the present invention and are not limitations of the present invention. After reading this specification, those skilled in the art may make modifications to the embodiments without any creative contribution as needed. However, such modifications are protected by the patent law as long as they are within the scope of the claims of the present invention.

[0041] Embodiment 1:

[0042] The present invention provides a scissor lift device with a hydraulic buffer 5 for maintenance, comprising a hydraulic buffer 5 and a scissor mechanism 4, wherein the hydraulic buffer 5 comprises a hydraulic cylinder 51 and a piston rod 52, wherein the hydraulic cylinder 51 has a lower connection end 6, and the piston rod 52 has an upper connection end 7, wherein the hydraulic buffer 5 can support the scissor mechanism 4 after being engaged with the scissor mechanism 4 through the upper connection end 7 and the lower connection end 6. The hydraulic buffer 5 is used for support, and when the scissor mechanism 4 applies pressure to the hydraulic buffer 5, the piston rod 52 will be gradually pressed into the hydraulic cylinder 51, and in this process, the characteristics of the hydraulic buffer 5 itself, i.e., strong buffering capacity and strong load capacity, are utilized. When the hydraulic buffer 5 supports the scissor mechanism 4, it is not only safe and stable, but also resists impact with buffering performance, avoiding damage to itself and the scissor mechanism 4, and in addition, the maximum load value that can be satisfied is relatively large, and in actual maintenance, only the hydraulic buffer 5 can be used for support, and there is no need to start the lifting mechanism 9 to provide additional support force, which can effectively save energy in the maintenance process that generally takes a long time. In this embodiment, the hydraulic buffer 5 has a lower connecting end 6 and an upper connecting end 7 which are specially connected to the scissor-type mechanism 4, and the connection is firm, which further ensures safety.

[0043] The scissor mechanism 4 includes two front and rear groups of scissor frames 42 and a cross-bracket 41 erected between the two groups of scissor frames 42, and the cross-bracket 41 is arranged on the left and right sides of the scissor mechanism 4 in the up-down direction; when the scissor frames 42 are unfolded, the cross-brackets 41 on the same side are separated from each other in the up-down direction, and when the scissor frames 42 are retracted, the cross-brackets 41 on the same side are close to each other in the up-down direction; the hydraulic buffer 5 is arranged between two adjacent cross-brackets 41 in the cross-bracket 41 on one side, and is engaged with the upper cross-bracket 41 through the upper connecting end 7, and is engaged with the lower cross-bracket 41 through the lower connecting end 6, and the entire scissor mechanism 4 is supported by supporting the two cross-brackets 41. The hydraulic buffer 5 may be damaged, and the load capacity of the hydraulic buffer 5 required for different actual situations is also different. Both situations require the replacement of the hydraulic buffer 5, so the connection between the lower connecting end 6 and the cross-bracket 41 in this embodiment is a detachable fixation.

[0044] As for the specific connection form between the hydraulic buffer 5 and the cross support rod 41, in this embodiment, the lower connecting end 6 preferably includes a lower arc seat 61, and the lower arc seat 61 has a lower arc groove 62 that can be completely abutted against the outer wall of the cross support rod 41 to achieve engagement; both ends of the lower arc seat 61 are rotatably connected with a lower opening and closing part 63, and the lower opening and closing part 63 is arc-shaped and can be completely abutted against the outer wall of the cross support rod 41, and the ends of the two lower opening and closing parts 63 are connected with lower fasteners 81, and the lower fasteners 81 can pull the ends of the two lower opening and closing parts 63 toward each other to achieve locking. The lower arc seat 61 is an integrally formed part, and its own structural strength is relatively high, and it plays a major role in the clamping support. The cross support rod 41 is a round rod, and the shape of the lower arc groove 62 matches the shape of the outer wall of the cross support rod 41. The lower arc seat 61 half-covers the cross support rod 41 through the lower arc groove 62, and the clamping relationship is very stable and reliable; and the lower opening and closing portion 63 makes the lower connecting end 6 completely clamp the cross support rod 41, further improving the firmness of the joint. When locking, the lower fastener 81 has the force to pull the ends of the two lower opening and closing portions 63 toward each other, so that the two lower opening and closing portions 63 clamp the cross support rod 41. During installation, the two lower opening and closing portions 63 are in an open state, and after the lower arc seat 61 is clamped with the cross support rod 41, the two lower opening and closing portions 63 clamp the cross support rod 41, and are locked with the lower fastener 81.

[0045] If the two ends of the two lower opening and closing parts 63 are in contact after they clamp the cross support rod 41, there is actually interference between the two. No matter how the lower fastener 81 increases the locking force, it is difficult to act on the two lower opening and closing parts 63. Therefore, in this embodiment, it is preferred that after the two lower opening and closing parts 63 are completely abutted against the outer wall of the cross support rod 41, there is a gap between the ends of the two lower opening and closing parts 63; in this way, when the lower fastener 81 increases the locking force, it can increase the clamping force between the lower opening and closing parts 63 and the cross support rod 41, further improving the locking effect. After locking, the lower connecting end 6 is difficult to move relative to the cross support rod 41, so it can be considered to have reached a fixed state. The lower opening and closing portion 63 has a mounting piece 64 at the end thereof for mounting the lower fastener 81. The mounting piece 64 is vertically arranged, and the locking force generated by the lower fastener 81 is perpendicular to the mounting piece 64. The lower fastener 81 pulls the two mounting pieces 64 to improve the transmission effect of the lower fastener 81 on the locking force, and further improves the locking effect. Preferably, the lower fastener 81 includes a bolt and a nut, and a through hole for the bolt to pass through is provided in the mounting piece 64. The bolt is simultaneously passed through the through holes of the two mounting pieces 64, and then the nut is tightened to generate the locking force.

[0046] In this embodiment, the upper connecting end 7 includes an upper arc seat 71, and the upper arc seat 71 has an upper arc groove 72 that can be completely attached to the outer wall of the horizontal support rod 41 to achieve engagement; both ends of the upper arc seat 71 are rotatably connected with an upper opening and closing portion 73, and the upper opening and closing portion 73 is arc-shaped and can be completely attached to the outer wall of the horizontal support rod 41, and the ends of the two upper opening and closing portions 73 are connected with an upper fastener 82, and the upper fastener 82 can pull the ends of the two upper opening and closing portions 73 toward each other to achieve locking. The functions of the upper arc seat 71, the upper opening and closing portion 73 and the upper fastener 82 correspond to the lower arc seat 61, the lower opening and closing portion 63 and the lower fastener 81, respectively, and the installation principle is also the same. Of course, it can be further preferred that there is also a gap between the ends of the two upper opening and closing portions 73 after the horizontal support rod 41 is clamped, and the ends of the two upper opening and closing portions 73 are provided with a mounting piece 64 for the upper fastener 82 to install, so as to better play the locking effect of the upper fastener 82. The composition of the upper fastener 82 is also the same as that of the lower fastener 81 .

[0047] The hydraulic buffer 5 is only used when it is used for maintenance. When the scissor-type lifting equipment is working normally, the hydraulic buffer 5 does not work and can be directly removed through the lower connecting end 6 and the upper connecting end 7. However, there is usually no extra space on the equipment for placement, and it must be removed every time after use, which is too cumbersome. Therefore, in this embodiment, it is preferred that a storage box with an upward opening is provided on the side wall of one of the scissor frames 42 facing the other scissor frame 42. When the lower fastener 81 is loosened, the lower connecting end 6 can move along the cross support rod 41 toward the scissor frame 42 with the storage box, and the lower fastener 81 can rotate relative to the cross support rod 41, so that the hydraulic buffer 5 falls into the storage box. When in use, the hydraulic buffer 5 is usually located in the middle of the cross support rod 41 for better support, and the storage box is set on the side wall of the scissor frame 42, which is a directly fixed connection relationship. The closer it is, the higher the firmness, and it can avoid interference with the lifting mechanism 9; so when storing the hydraulic buffer 5, first release the engagement between the upper connecting end 7 and the cross support rod 41, and then loosen the nut in the lower fastener 81 so that the lower opening and closing part 63 no longer clamps the cross support rod 41, and the lower connecting end 6 can move or rotate relative to the cross support rod 41, first move toward the scissor frame 42 with the storage box, until the hydraulic buffer 5 is aligned with the storage box, and then rotate the lower connecting end 6 relative to the cross support rod 41, and the hydraulic buffer 5 falls into the storage box to achieve storage. Furthermore, it is preferred that a detachable cover plate is set at the opening of the storage box. When the hydraulic buffer 5 is stored in the storage box, the cover plate is installed to prevent the hydraulic buffer 5 from detaching from the storage box and affecting the normal operation of the equipment.

[0048] Since the piston rod 52 will enter and exit the hydraulic cylinder 51 when the hydraulic buffer 5 is working, in order to prevent impurities from entering the hydraulic cylinder 51 through the gap and affecting the normal operation of the hydraulic cylinder 51, in this embodiment, the hydraulic buffer 5 preferably also includes a dust cover 53 sleeved on one end of the hydraulic cylinder 51, the dust cover 53 is fixed on the piston rod 52, and the dust cover 53 can follow the piston rod 52 to move relative to the hydraulic cylinder 51, and the dust cover 53 surrounds one end of the hydraulic cylinder 51 in the circumferential direction, is sealed and fixed to the piston rod 52 on one axial side, and is open on the other axial side for the hydraulic cylinder 51 to extend into. In this way, the dust cover 53 can prevent impurities from entering the hydraulic cylinder 51. The hydraulic buffer cylinder has a maximum load capacity. If this load capacity is exceeded, it will be damaged and fail. Therefore, in this embodiment, a warning scale is preferably set on the outer wall of the hydraulic cylinder 51. When the dust cover 53 moves, a visible distance change occurs between its lower edge and the warning scale. When the lower edge of the dust cover 53 reaches the warning scale, the hydraulic buffer 5 reaches the maximum load capacity. When using the hydraulic buffer 5, firstly, the lifting mechanism 9 is used to lift the scissor mechanism 4, so that the distance between the two adjacent horizontal support rods 41 is greater than the total length of the hydraulic buffer 5 in the initial state, and then the hydraulic buffer 5 is lifted up from the storage box, so that the upper arc groove 72 in the upper arc seat 71 of the upper connecting end 7 is aligned with the upper horizontal support rod 41, and then the descending function module of the lifting mechanism 9 is started to drive the scissor mechanism 4 to contract and descend, so that the horizontal support rod 41 enters the upper arc groove 72, and continues to descend so that the hydraulic buffer 5 supports the horizontal support rod 41. In the process of continuing to descend, it is necessary to stop the lifting mechanism 9 from descending in time before the lower edge of the dust cover 53 exceeds the warning scale to avoid damage to the hydraulic buffer 5. In this way, only the scissor mechanism 4 is pressed on the hydraulic buffer 5, which is usually a load that the hydraulic buffer 5 can withstand.

[0049] However, in actual operation, the operator may forget to close the lifting mechanism 9 if he / she is not careful, and the lifting mechanism 9 continues to descend. The hydraulic buffer 5 bears the pressure of the scissor mechanism 4 and the thrust of the lifting mechanism 9. When the lower edge of the dust cover 53 exceeds the warning scale, the hydraulic buffer 5 is damaged. Therefore, in this embodiment, the scissor-type lifting device preferably also includes a lifting mechanism 9, a controller and a switch. The lifting mechanism 9 supports the scissor mechanism 4 and has a rising function module and a falling function module that can push the scissor mechanism 4 to extend or contract; the switch is arranged on the hydraulic buffer 5, and the switch can be triggered when the lower edge of the dust cover 53 reaches the warning scale; the controller can receive the signal of the switch and can control the lifting mechanism 9 to stop the descending action to avoid damage to the hydraulic buffer 5.

[0050] Based on the above-mentioned scissor-type lifting device with a hydraulic buffer 5 for maintenance, the present invention proposes a control method for a scissor-type lifting device with a hydraulic buffer 5 for maintenance, specifically a control method during maintenance, comprising the following steps:

[0051] S01: starting the lifting function module of the lifting mechanism 9 to drive the scissor mechanism 4 to extend until the distance between two adjacent horizontal support rods 41 in the vertical direction exceeds the total length of the hydraulic buffer 5 in the initial state;

[0052] S02: taking out the hydraulic buffer 5 from the storage position and propping it upward, so that the upper connecting end 7 of the hydraulic buffer 5 is aligned with the horizontal support rod 41 of the scissor mechanism 4;

[0053] S03: Activate the descending function module of the lifting mechanism 9 to drive the scissor mechanism 4 to contract, and the cross support rod 41 located above the hydraulic buffer 5 and closest to the upper connecting end 7 moves toward the upper connecting end 7 until it is engaged with the upper connecting end 7;

[0054] S04: the lifting mechanism 9 continues to drive the scissor mechanism 4 to contract, the cross support rod 41 squeezes the hydraulic buffer 5, the hydraulic buffer 5 gradually contracts, and the lower edge of the dust cover 53 gradually approaches the warning scale;

[0055] S05: Before the lower edge of the dust cover 53 exceeds the warning scale, the descending function module of the lifting mechanism 9 is turned off to stop the contraction of the scissor mechanism 4, and the hydraulic buffer 5 supports the scissor mechanism 4.

[0056] As a further improvement to the above step S05, when the lower edge of the dust cover 53 reaches the warning scale in step S05, the dust cover 53 triggers the switch, and the controller controls the lifting mechanism 9 to close the descending function module after receiving the signal from the switch.

[0057] As a further improvement, there is a step S06 after step S05. After the descending function module of the lifting mechanism 9 is turned off, the controller controls the lifting mechanism 9 to start the ascending function module. The supporting force output by the ascending function module can maintain the static state of the scissor mechanism 4 together with the hydraulic buffer 5, thereby reducing the burden of the hydraulic buffer 5. Even in the extreme case that the hydraulic buffer 5 suddenly fails, the lifting mechanism 9 can still play a supporting role to further ensure safety.

[0058] The above control method utilizes the lifting mechanism 9, so it is aimed at repairing parts other than the lifting mechanism 9. If the lifting mechanism 9 needs to be repaired, another control method is required. The present invention provides a control method for a scissor-type lifting device with a hydraulic buffer 5 for maintenance, comprising the following steps:

[0059] S01: The scissor mechanism 4 is pulled upward to extend the scissor mechanism 4 until the distance between two adjacent horizontal support rods 41 in the vertical direction exceeds the total length of the hydraulic buffer 5 in the initial state;

[0060] S02: taking out the hydraulic buffer 5 from the storage position and propping it upward, so that the upper connecting end 7 of the hydraulic buffer 5 is aligned with the horizontal support rod 41 of the scissor mechanism 4;

[0061] S03: Keep pulling the scissor mechanism 4, and gradually lower the scissor mechanism 4 by using the pulling force, so that the scissor mechanism 4 contracts, and the cross support rod 41 located above the hydraulic buffer 5 and closest to the upper connecting end 7 moves toward the upper connecting end 7 until it is engaged with the upper connecting end 7;

[0062] S04: As the scissor mechanism 4 continues to contract, the hydraulic buffer 5 gradually supports the tie rod;

[0063] S05: Remove the lifting force so that the scissor mechanism 4 is fully supported by the hydraulic buffer 5.

[0064] The hanging pulling force in this control method is provided by the suspension equipment.

[0065] Embodiment 2:

[0066] The lifting mechanism 9 of the present invention adopts the following linear actuator with a contact safety nut, including a center screw 1, a transmission nut mechanism 2 and a safety nut mechanism 3, wherein the center screw 1 has a spiral raceway 11, and the safety nut mechanism 3 includes a safety nut seat 31 sleeved on the periphery of the center screw 1, and there is no contact between the safety nut seat 31 and the center screw 1, and a limiting hole 32 pointing to the center screw 1 is opened on the safety nut seat 31, and an elastic buffer 33 is arranged in the limiting hole 32, and a safety ball 34 is arranged between the elastic buffer 33 and the center screw 1; the elastic buffer The end of 33 away from the safety ball 34 can be supported, specifically, it can be fixedly connected to the inner wall of the limiting hole 32, or the limiting hole 32 is blocked at the end away from the center screw 1 and has a bottom surface, and the elastic buffer 33 directly rests on this bottom surface; the safety ball 34 partially falls in the spiral raceway 11 and partially is located in the limiting hole 32, the safety ball 34 can roll along the spiral raceway 11 and can move along the limiting hole 32, the safety ball 34 is completely fitted with the spiral raceway 11, and the safety ball 34 can roll smoothly in the spiral raceway 11. When the linear drive is operating normally, the transmission nut mechanism 2 plays a major transmission role, and the safety nut mechanism 3 does not work but still needs to move with the transmission nut. Only the safety ball 34 in the safety nut mechanism 3 falls into the spiral raceway 11 of the center screw 1 and can roll along the spiral raceway 11. The remaining components in the safety nut mechanism 3 do not contact the center screw 1, but the safety nut mechanism 3 is engaged with the center screw 1 through the safety ball 34; the safety ball 34 is located between the elastic buffer 33 and the center screw 1. When subjected to external force, the safety ball 34 can overcome the elastic force of the elastic buffer 33 and move in the limiting hole 32, so the safety ball 34 is not tightly pressed in the spiral raceway 11, but only rolls along the spiral raceway 11, so the existence of the safety ball 34 will not affect the normal operation of the transmission nut mechanism 2.When the transmission nut mechanism 2 fails, it is usually caused by the loss of the balls in the transmission nut mechanism 2. At this time, along the axial direction of the center screw 1, the safety balls 34 in the safety nut mechanism 3 are tightly pressed against the side walls of the spiral raceway 11, and the safety balls 34 themselves are completely fitted with the spiral raceway 11, so there is no axial displacement of the safety balls 34. At the moment of action, there is no instantaneous violent collision between the safety balls 34 and the center screw 1, which ensures the stability of the entire linear drive and avoids damage to the safety balls 34 and the center screw 1. Part of 34 is located in the limiting hole 32, so the axial displacement of the safety nut seat 31 can be limited by clamping the limiting hole 32, so that the safety nut mechanism 3 will not cause the linear drive to have axial position error when working, and the safety ball 34 also plays the role of replacing the lost ball in the transmission nut mechanism 2 at this time, temporarily playing a transmission role, so that the linear drive can still complete the current lifting task, or descend to a safe height. In short, the operation accuracy can be guaranteed, and there is no need to re-calibrate the accuracy when the transmission nut mechanism 2 is replaced later. In the lateral direction perpendicular to the axis of the center screw 1, the safety nut seat 31 is pressed toward the center screw 1, and the safety ball 34 will overcome the elastic force of the elastic buffer 33 and move toward the limiting hole 32. The elastic buffer 33 plays a buffering role to avoid violent vibrations of the safety nut mechanism 3 and the linear drive, thereby ensuring the safety of the lifting equipment. However, in this direction, the safety ball 34 cannot be tightly pressed into the spiral raceway 11. The safety nut seat 31 is directly pressed on the center screw 1, playing the role of locking the center screw 1 by the safety nut mechanism 3 to ensure safety. In short, the design of the contact safety nut enables the linear drive to always maintain safety, stability and precision without loss in the conversion process when the transmission nut mechanism 2 fails and the safety nut mechanism 3 intervenes to play a role.

[0067] The limiting hole 32 in this embodiment points to the center screw 1, and the specific extension direction of the limiting hole 32 is perpendicular to the axial direction of the center screw 1. There is only one safety ball 34 in each limiting hole 32 in the safety nut mechanism 3. Therefore, in order to ensure the overall effect of the safety nut, in this embodiment, it is preferred that a plurality of limiting holes 32 are arranged circumferentially on the safety nut seat 31, and each limiting hole 32 is provided with the elastic buffer 33 and the safety ball 34. In this embodiment, the safety nut mechanism 3 mainly relies on the direct extrusion of the safety nut seat 31 and the center screw 1 to resist the lateral force and play a locking role, but the inner wall of the safety nut seat 31 is smoothly attached to the center screw 1. If the lateral force is small, the locking effect is general, and the locking effect in the axial direction is very general. Therefore, in this embodiment, the inner wall of the safety nut seat 31 preferably has a spiral top tooth 35, and the spiral top tooth 35 extends into the spiral raceway 11 and is spaced apart from the center screw 1. When the transmission nut mechanism 2 operates normally, the spiral top tooth 35 does not contact the center screw 1; when the transmission nut mechanism 2 fails, the safety ball 34 still plays the above-mentioned role, and the safety nut seat 31 no longer directly squeezes the center screw 1, but is squeezed into the spiral raceway 11 of the center screw 1 through the spiral top tooth 35. In this way, the spiral top tooth 35 can directly press the center screw 1 in the lateral direction, and the locking effect is good. At the same time, it can also share the burden of the safety ball 34 in the axial direction, thereby ensuring the strength and reliability of the safety nut mechanism 3.

[0068] When the transmission nut mechanism 2 operates normally, the safety ball 34 is not tightly pressed in the spiral raceway 11 and rolls in the spiral raceway 11, so it will not have a significant impact on the normal operation of the transmission nut mechanism 2. However, the friction between the safety ball 34 and the spiral raceway 11 will still have some impact on the normal operation of the transmission nut mechanism 2, especially the operating efficiency, accuracy and energy consumption. Therefore, in this embodiment, the limiting hole 32 is preferably filled with oil, the cross-sectional diameter of the limiting hole 32 is consistent with the diameter of the safety ball 34, the outer ring of the safety ball 34 is completely close to the inner wall of the limiting hole 32, and the safety ball 34 clamps the limiting hole 32 to limit the safety nut seat 31. The movement of the safety ball 34 in the limiting hole 32 is fully limited by the limiting hole 32, which is very stable, and the safety ball 34 blocks the limiting hole 32 to prevent the oil from directly flowing out of the limiting hole 32; and the oil is in direct contact with the surface of the safety ball 34, and the safety ball 34 with oil on the surface rolls in the spiral raceway 11, and the oil plays a lubricating role, reducing the friction between the safety ball 34 and the spiral raceway 11, and further reducing the impact of the safety nut mechanism 3 on the normal operation of the transmission nut mechanism 2. In addition, the oil in the limiting hole 32 can also play a certain buffering role on the safety ball 34, further improving the shock absorption effect.

[0069] As a further improvement, in this embodiment, the limiting hole 32 preferably passes through the inner and outer side walls of the safety nut seat 31, and the safety ball 34 blocks the outlet of the limiting hole 32 close to the center screw 1. The limiting hole 32 is detachably installed with a plunger 36 away from the entrance of the center screw 1, and the plunger 36 blocks the entrance of the limiting hole 32. The elastic buffer 33 is located between the plunger 36 and the safety ball 34. The design of the limiting hole 32 passing through and the plunger 36 can facilitate the installation of the elastic buffer 33 and the safety ball 34, and can also facilitate the oil. Infusion; during installation, first install the safety nut seat 31, then put the safety ball 34 and the elastic buffer 33 into the limiting hole 32 in turn, then inject oil, and finally install the plunger 36 at the entrance of the limiting hole 32 for blocking. The installation is very convenient, and there is no need to manufacture the elastic buffer 33, the safety ball 34 and the safety nut seat 31 together during production, which reduces the manufacturing cost and maintenance cost; during use, the oil will continue to be lost. When it is necessary to add oil, remove the plunger 36, then replenish the injection oil, and then install the plunger 36 for continued use. Preferably, the plunger 36 and the limiting hole 32 are threadedly connected.

[0070] The spiral top teeth 35 effectively improve the locking ability of the safety nut mechanism 3, but in actual operation, when the safety nut mechanism 3 is in effect, the linear drive is still required to operate to complete the current lifting task or descend to a safe height. Therefore, under the action of the driving force, the spiral top teeth 35 on the safety nut mechanism 3 need to be able to slide along the spiral raceway 11 to achieve the movement of the safety nut mechanism 3. In this embodiment, it is preferred that a gap is provided between the safety nut seat 31 and the transmission nut mechanism 2 to form an oil replenishing chamber 38, and the oil replenishing chamber 38 surrounds the center screw 1. A transfer channel 37 connecting the limiting channel 32 and the oil replenishing chamber 38 is provided in the safety nut seat 31. When the oil is poured, the limiting channel 32, the transfer channel 37 and the oil replenishing chamber 38 are all filled with oil. The oil in the oil replenishing chamber 38 flows directly into the spiral raceway 11 of the center screw 1, reducing the friction between the spiral top teeth 35 and the spiral raceway 11, so that the safety nut mechanism 3 can more easily move along the center screw 1 under the drive of the driving force when it is working.

[0071] In this embodiment, the limiting holes 32 are preferably arranged in a circular array along the circumference of the safety nut seat 31, which refers to the planar arrangement of the limiting holes 32 in the axial direction of the center screw 1. In fact, these limiting holes 32 may be spaced apart along the axial direction of the center screw 1, and are not on the same cross section. This embodiment is further improved, and preferably all the outlets of the limiting holes 32 are arranged on the spiral top teeth 35 along the spiral extension direction of the spiral top teeth 35, so that all the safety balls 34 are also arranged along the spiral extension direction of the spiral top teeth 35, so that the safety balls 34 are combined with the spiral top teeth 35, and play their respective roles at the same position of the spiral raceway 11, and play a locking role in the axial and lateral directions at the same position, thereby improving the locking effect. In this embodiment, the elastic buffer 33 is a spring, and the diameter of the spring is smaller than the diameter of the safety ball 34. There is no need for the two to be connected, and they can interact with each other by directly abutting against each other, which is convenient for installation and has a good force transmission effect.

[0072] The present invention provides an aerial work platform, including the linear drive with contact safety nut, wherein the safety nut mechanism 3 in the linear drive is safe, stable and accurate when it is in effect, and can ensure that the aerial work platform is still safe, stable and accurate when encountering a linear drive failure. The aerial work platform can be a commonly used aerial work platform such as a scissor-type aerial work platform, an aerial work platform with a cargo platform, etc.

[0073] Embodiment three:

[0074] The linear drive in the second embodiment is mainly used in the whole vehicle of the aerial work platform. When the linear drive fails and the safety nut mechanism is activated, in order to ensure safety, it is necessary to stop working in time and prompt the operator to perform maintenance. Therefore, this embodiment is improved on the basis of the linear drive in the second embodiment, that is, the linear drive in this embodiment adopts the linear drive in the second embodiment, and then adds parts on the basis of it to realize the fault detection function; specifically, the linear drive in this embodiment also includes a transmission control assembly, and the transmission control assembly includes a motor that drives the rotation of the central screw and a motor controller that controls the operation of the motor. The motor controller can directly receive external operation status signals and parse them into action instructions to control the operation of the motor. At present, the commonly used method in the prior art in this field is that the operation status signal of the handle is transmitted to the vehicle controller (VCU), and the vehicle controller (VCU) analyzes the operation status signal and then transmits it to the micro control unit (MCU) in the motor controller. In this method, the vehicle controller (VCU) is connected to the handle and the motor controller by wires respectively, so the wiring is complicated; the handle is a button device for the operator to perform instructions such as ascending, descending, and maintaining height. The number of its operation status signals is small, so the corresponding vehicle controller (VCU) has simple functions, and it is easy to integrate these functions in the micro control unit (MCU) of the motor controller in hardware. Therefore, the motor controller in this embodiment has a micro control unit (MCU) and integrates the functions of the vehicle controller (VCU), which can directly receive the operation status signal of the handle and analyze it. In this way, the vehicle controller (VCU) is directly cancelled in hardware, reducing costs, improving integration, reducing complicated lines, and reducing failure rates. At the same time, the operation status signal sent by the handle is an external operation status signal for the motor controller. Since the operation status signal transmitted by the handle to the motor controller is simple and the handle is directly operated manually by the operator, the handle and the motor controller can use traditional reliable wire connections to transmit signals, or wireless signal communication can be used to transmit signals.

[0075] When the linear actuator is actually used in the whole vehicle of the aerial work platform, the whole vehicle has a platform. The fault detection of the motor controller in this embodiment is mainly judged by the three quantities of platform height value, platform weight value and motor current value. Therefore, the linear actuator in this embodiment also includes a height sensor for monitoring the platform height value, a weight sensor for monitoring the platform weight value and a current sensor for monitoring the motor current value. It is a real-time monitoring during the operation of rising or falling. The motor controller stores a calibration database for comparing the height value, weight value and current value. The motor controller can obtain the monitoring data of the height sensor, the weight sensor and the current sensor in real time and judge whether the real-time current value exceeds the calibration current value. Under normal operation, the real-time height value and weight value correspond to a calibration current value in the calibration database. If the monitored real-time current value exceeds this calibration current value, it proves that the linear actuator is subjected to a large additional resistance. It is very likely that the transmission nut mechanism fails and the safety nut mechanism takes effect. The safety nut mechanism acts on the central screw to increase the resistance, but it cannot be completely determined that it is caused by the effectiveness of the safety nut mechanism.

[0076] Once the above-mentioned real-time current value of the linear drive in this embodiment is greater than the calibrated current value, the motor controller will control the motor to stop, so that the transmission nut mechanism will no longer rise or fall, but maintain the current height to avoid danger; the motor stops rotating means that the main shaft stops, and the center screw stops, and the actual motor still has power output to maintain the current state. At this time, the linear drive enters the self-balancing state, and it is necessary to perform a fault detection again to determine whether the safety nut mechanism is effective; so the motor controller described in this embodiment has a standard current value calculation module. In the self-balancing state, the calculation module can calculate the corresponding standard current value according to the height value and weight value of the current platform, and judge whether the real-time current value is lower than the standard current value. The standard current value refers to the current value that the motor should reach to maintain the self-balancing state when the safety nut mechanism is not effective. If the real-time current value is not lower than the standard current value, it proves that there is no additional resistance, the safety nut mechanism is not effective, and the transmission nut mechanism has not failed. The first fault detection previously performed during the movement may have a detection deviation due to other factors. In this way, the motor controller controls the motor to rotate to continue to execute the initial action command, and the linear drive returns to normal working state. If the real-time current value is lower than the standard current value, it proves that there is additional resistance, and it is determined that the safety nut mechanism has been effective and the transmission nut mechanism has failed.

[0077] The height sensor, weight sensor and current sensor in this embodiment all need to monitor the equipment in real time, and have high requirements on the efficiency, accuracy and efficiency of numerical judgment of data monitoring, and need to minimize the delay. Therefore, in this embodiment, it is preferred that the height sensor, weight sensor and current sensor are all connected to the motor controller through wires to improve the efficiency of data transmission and numerical judgment, thereby improving the accuracy of the entire fault monitoring. The operating status signals transmitted by the handle to the motor controller are simple and few in number, and the handle is manually operated by the operator, so it is preferred that the motor controller has a wireless communication conversion module that can receive and analyze external operating status signals, reduce the setting of wires, and facilitate manual operation by the operator, and the reliability and speed of wireless communication are also sufficient to meet the transmission of simple operating status signals in the handle.

[0078] If the safety nut mechanism is proven to be effective according to the above two fault detections, it is determined that the transmission nut mechanism has failed, and it is necessary to end normal operation and repair it in time. In this embodiment, the linear drive preferably also includes a warning light. When the motor controller determines that the safety nut mechanism is effective, it can control the warning light to flash, informing the on-site operator that a fault has occurred and the working state needs to be ended. Usually, after the user finds that the linear drive has failed, it is necessary to notify the manufacturer's after-sales personnel to come for repair, which causes trouble to the user. In order to further improve the after-sales service, this embodiment incorporates after-sales service into the fault detection strategy. Preferably, the linear drive also includes a remote terminal for communicating with the cloud server through the network. The motor controller can send the fault code to the remote terminal, and the remote terminal is used to transmit the fault code to the cloud server. The cloud server is operated by the manufacturer. After receiving the fault code, the detailed information can be directly sent to the after-sales personnel in the nearby area. After being assigned, the after-sales personnel can rush to the user in time for repair.

[0079] When the motor controller determines that the safety nut mechanism is effective and controls the linear drive to stop executing the lifting command, temporary protection measures are still required; specifically, if the initial action command is to rise, the motor controller controls the motor to stop, but the motor still has output power to maintain the current state to ensure the safety of the platform for goods or personnel; if the initial action command is to descend, the motor controller stops the motor and the brake of the motor is released. The motor is in a state of no output power, and the main shaft of the motor will rotate under the drive of external force. The motor described in this embodiment can convert kinetic energy into electrical energy when it reverses, so the linear drive can achieve energy recovery when it freely falls and contracts, and the reversal of the motor will provide resistance to the descent and contraction of the linear drive to avoid the platform from descending too fast and causing danger.

[0080] The linear actuator of this embodiment has a fault detection function, which gives rise to a set of fault detection methods adapted thereto in actual use. Therefore, a fault detection method of a linear actuator with a contact safety nut of the present invention comprises the following steps:

[0081] S01: The motor controller directly receives the external operation state signal and parses it into an action instruction capable of controlling the motor;

[0082] S02: Controlling the operation of the motor according to the action instruction obtained by the analysis;

[0083] S03: When the action command is to rise or fall, the motor is operated to make the linear drive perform the action of rising or falling, and at the same time, the motor controller determines in real time whether the monitored real-time current value exceeds the calibrated current value corresponding to the height and weight value of the current platform in the database. If the real-time current value does not exceed the calibrated current value, the linear drive continues to perform the action of rising or falling;

[0084] S04: If the motor controller determines that the real-time current value monitored in real time exceeds the calibrated current value corresponding to the height and weight of the current platform in the database at a certain moment during the execution of the ascending or descending action, the motor controller controls the motor to change the output power so that the linear drive stops ascending or stops descending and maintains at the current height;

[0085] S05: the linear drive enters a self-balancing state, the motor controller calculates a standard current value for maintaining the self-balancing state according to the height and weight of the current platform, and determines in real time whether the monitored real-time current value is lower than the calculated standard current value for maintaining the self-balancing state. If the real-time current value is not lower than the standard current value, it is determined that the safety nut is not effective, and the motor controller controls the motor to continue to execute the initial ascending or descending action instruction;

[0086] S06: If the real-time current value in the self-balancing state is lower than the standard current value, the motor controller determines that the safety nut mechanism is effective;

[0087] S07: If the initial action instruction is to rise, the motor controller stops the linear drive from rising, and the motor maintains the current state of the linear drive; if the action instruction is to fall, the motor controller stops the motor from running, and the brake of the motor is released, the linear drive falls freely, and at the same time drives the motor to reverse, so as to realize energy recovery of the motor;

[0088] S08: The motor controller controls the alarm light to flash and sends a fault code to the remote terminal, the remote terminal transmits the fault code to the cloud server, and the cloud server notifies after-sales personnel via a wireless signal.

[0089] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. Control method for a scissor lift device with a hydraulic buffer for maintenance, characterized in that, the scissor lift device includes a hydraulic buffer (5) and a scissor mechanism (4), the hydraulic buffer (5) includes a hydraulic cylinder (51) and a piston rod (52), the hydraulic cylinder (51) has a lower connection end (6), the piston rod (52) has an upper connection end (7), and after the hydraulic buffer (5) is engaged with the scissor mechanism (4) through the upper connection end (7) and the lower connection end (6), it can support the scissor mechanism (4); the hydraulic buffer (5) further includes a dust cover (53) sleeved on one end of the hydraulic cylinder (51); a warning scale is provided on the outer wall of the hydraulic cylinder (51); the lift device further includes a lifting mechanism (9), a controller and a switch; both the left and right sides of the scissor mechanism (4) have horizontal support rods (41) arranged in the vertical direction, and the hydraulic buffer (5) engages and supports two adjacent horizontal support rods (41) located on the same side in the vertical direction; the scissor mechanism (4) further includes two groups of scissor frames (42) in the front and back, and the horizontal support rods (41) are erected between the two groups of scissor frames (42); the lower connection end (6) can rotate relative to the horizontal support rod (41) it engages with, and a storage box with an upward opening is provided on the side wall of one scissor frame (42) facing the other scissor frame (42), and the hydraulic buffer (5) can be rotated through the lower connection end and fall into the storage box; when the lift device is used to repair parts other than the lifting mechanism (9), the method specifically includes the following steps: S01: Start the rising function module of the lifting mechanism (9) to drive the scissor mechanism (4) to extend until the distance between two adjacent horizontal support rods (41) in the vertical direction exceeds the total length of the hydraulic buffer (5) in the initial state; S02: Take out the hydraulic buffer (5) from the storage position and support it upward so that the upper connection end (7) of the hydraulic buffer (5) is aligned with the horizontal support rod (41) of the scissor mechanism (4); S03: Start the descending function module of the lifting mechanism (9) to drive the scissor mechanism (4) to contract, and the horizontal support rod (41) located above the hydraulic buffer (5) and closest to the upper connection end (7) moves towards the upper connection end (7) until it engages with the upper connection end (7); S04: The lifting mechanism (9) continues to drive the scissor mechanism (4) to contract, the horizontal support rod (41) presses the hydraulic buffer (5), the hydraulic buffer (5) gradually contracts, and the lower edge of the dust cover (53) gradually approaches the warning scale; S05: Before the lower edge of the dust cover (53) exceeds the warning scale, turn off the descending function module of the lifting mechanism (9) to stop the contraction of the scissor mechanism (4), and the hydraulic buffer (5) supports the scissor mechanism (4); S06: After the descending function module of the lifting mechanism (9) is turned off, the controller controls the lifting mechanism (9) to start the ascending function module, and the supporting force output by the ascending function module can maintain the static state of the scissor mechanism (4) together with the hydraulic buffer (5).

2. A control method for a scissor lift with a hydraulic buffer for maintenance according to claim 1, It is characterized in that The dust cover (53) is fixed on the piston rod (52), and the dust cover (53) can follow the piston rod (52) to generate movement relative to the hydraulic cylinder (51).

3. A control method for a scissor lift with a maintenance hydraulic buffer according to claim 2, It is characterized in that When the dust cover (53) moves, a visible distance change occurs between its lower edge and the warning scale, and when the lower edge of the dust cover (53) reaches the warning scale, the hydraulic buffer (5) reaches a maximum load.

4. A control method for a scissor lift with a maintenance hydraulic buffer according to claim 3, It is characterized in that The lifting mechanism (9) supports the scissor-type mechanism (4) and has a lifting function module and a lowering function module capable of pushing the scissor-type mechanism (4) to extend or retract; the switch is arranged on the hydraulic buffer (5), and the switch can be triggered when the lower edge of the dust cover (53) reaches the warning scale; the controller can receive a signal from the switch and can control the lifting mechanism (9) to stop the descending action.

5. A control method for a scissor lift with a maintenance hydraulic buffer according to claim 1, It is characterized in that In step S05, when the lower edge of the dust cover (53) reaches the warning scale, the dust cover (53) triggers the switch, and after receiving the signal from the switch, the controller controls the lifting mechanism (9) to close the descending function module.

6. A method for controlling a scissor lift with a hydraulic buffer for maintenance, It is characterized in that The scissor-type lifting device comprises a hydraulic buffer (5) and a scissor-type mechanism (4), wherein the hydraulic buffer (5) comprises a hydraulic cylinder (51) and a piston rod (52), wherein the hydraulic cylinder (51) has a lower connecting end (6), and the piston rod (52) has an upper connecting end (7), and the hydraulic buffer (5) is able to support the scissor-type mechanism (4) after being engaged with the scissor-type mechanism (4) via the upper connecting end (7) and the lower connecting end (6); The hydraulic buffer (5) further comprises a dust cover (53) sleeved on one end of the hydraulic cylinder (51); A warning scale is provided on the outer wall of the hydraulic cylinder (51); The lifting device also includes a lifting mechanism (9), a controller and a switch; The left and right sides of the scissor mechanism (4) are both provided with transverse support rods (41) arranged in the up-down direction, and the hydraulic buffer (5) connects and supports two transverse support rods (41) located in the same side and adjacent to each other in the up-down direction; The scissor mechanism (4) further comprises two front and rear groups of scissor frames (42), the transverse support rod (41) being mounted between the two groups of scissor frames (42); the lower connecting end (6) being capable of rotating relative to the transverse support rod (41) to which it is connected, a storage box with an upward opening being provided on a side wall of one scissor frame (42) facing the other scissor frame (42), and the hydraulic buffer (5) being capable of rotating through the lower connecting end until it falls into the storage box; When the lifting device is used to repair the lifting mechanism (9), the method specifically comprises the following steps: S01: the scissor mechanism (4) is pulled upward to extend the scissor mechanism (4) until the distance between two adjacent horizontal support rods (41) in the vertical direction exceeds the total length of the hydraulic buffer (5) in the initial state; S02: taking the hydraulic buffer (5) out of the storage position and propping it upwards, so that the upper connecting end (7) of the hydraulic buffer (5) is aligned with the horizontal support rod (41) of the scissor mechanism (4); S03: Keep pulling the scissor mechanism (4), and gradually lower the scissor mechanism (4) using the pulling force, so that the scissor mechanism (4) contracts, and the cross support rod (41) located above the hydraulic buffer (5) and closest to the upper connecting end (7) moves toward the upper connecting end (7) until it engages with the upper connecting end (7); S04: As the scissor mechanism (4) continues to contract, the hydraulic buffer (5) gradually supports the cross support rod (41); S05: removing the lifting force so that the scissor mechanism (4) is completely supported by the hydraulic buffer (5).

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