Fixed wing type unmanned aerial vehicle undercarriage

Abstract

The invention relates to the field of unmanned aerial vehicles, in particular to a fixed wing type unmanned aerial vehicle undercarriage. An existing unmanned aerial vehicle landing gear has the defects that the installation process is tedious and inconvenient, the inertia is large during landing, landing is not stable enough, and site limitation is large. A fixed wing type unmanned aerial vehicle undercarriage comprises a frame body and the like. A bottom plate is fixedly connected to the frame body, two fixing shafts are fixedly connected to the bottom plate, and the two fixing shafts are symmetrically arranged. After the unmanned aerial vehicle takes off, four electric push rods can drive landing wheels to be folded, when the unmanned aerial vehicle lands, first buffer springs can buffer inertia force of the unmanned aerial vehicle, the landing gear can be rapidly mounted and dismounted, the unmanned aerial vehicle is more convenient to assemble, the situation that the landing gear is loosened due to the fact that a rotary disc is touched by mistake can be prevented, and after the unmanned aerial vehicle takes off, the unmanned aerial vehicle is more convenient to use. The four landing wheels can be folded, the air resistance during flight of the unmanned aerial vehicle is reduced, and the flight efficiency and performance are improved.

Description

Technical Field

[0001] The present invention relates to the field of unmanned aerial vehicles, and in particular to a fixed-wing unmanned aerial vehicle landing gear. Background Art

[0002] Fixed-wing UAV is a type of unmanned aerial vehicle with fixed wing shape, which consists of fuselage, wings, tail, propulsion system and landing gear. The landing gear of a UAV is an important part of its structure, especially for fixed-wing UAVs, which not only affects the take-off and landing performance of the UAV, but also involves the safety and convenience of ground operations.

[0003] However, the current UAV landing gear is installed with a fixed wheel landing gear through a bolt mechanism to support the weight of the UAV when it is on the ground, and the elastic material is used to help it achieve a safe landing. The installation process is relatively cumbersome and inconvenient. The UAV has a large inertia when landing, and the landing is not stable enough. In addition, the site restrictions are large, and a larger site is required to provide a buffer to slow down the UAV. Summary of the invention

[0004] In view of the shortcomings or deficiencies of the above-mentioned prior art, the present invention provides a fixed-wing UAV landing gear, which can be quickly installed and disassembled, making the UAV assembly more convenient, and can also make the UAV land more smoothly, optimize the take-off and landing distances, and reduce the restrictions of the site on the UAV.

[0005] A fixed-wing UAV landing gear comprises a frame body, a base plate fixedly connected to the frame body, two fixed shafts fixedly connected to the base plate, the two fixed shafts are symmetrically arranged, two pulley frames are rotatably provided on the two fixed shafts, two pulley frames located on the same fixed shaft form a group, a mounting block is slidably connected to the pulley frame, a buffer spring is connected between the pulley frame and the mounting block, the buffer spring is set on the pulley frame, a landing wheel is rotatably connected to the mounting block, a quick loading and unloading assembly is arranged on the frame body, and a wheel frame retracting and extending assembly is arranged on the base plate.

[0006] As a preferred technical solution of the present invention, the quick-loading and disassembly assembly includes an inclined surface block, four inclined surface blocks are slidably connected to the frame body, and connecting pipes are fixedly connected to the four inclined surface blocks. Two connecting pipes close to each other form a group, and two inclined surface blocks respectively connected to two connecting pipes of the same group form a group. A central axis is slidably connected between the two connecting pipes of the same group, and a reset spring is connected between the central axis and the two connecting pipes of the same group. The reset spring is sleeved on the central axis, and two connecting frames are fixedly connected between the two groups of inclined surface blocks. The two connecting frames are symmetrically arranged, and arc guide rods are fixedly connected to the two connecting frames. The frame body The upper part is rotatably connected with a slot plate, and the slot plate is provided with an embedded card slot and two arc grooves. The bottom ends of the two arc guide rods are respectively located in the two arc grooves on the slot plate, and the slot plate is rotatably connected with the bottom plate, and a sliding shaft is slidably sleeved on the slot plate, and an embedded card block is fixedly connected to the top of the sliding shaft, and the embedded card block and the embedded card slot on the slot plate are located in the same vertical direction, and a ring gasket is rotatably connected in the slot plate, and the sliding shaft passes through the ring gasket, and a rotation spring is connected between the ring gasket and the top of the inner wall of the slot plate, and the rotation spring is sleeved on the sliding shaft, and a turntable is fixedly connected to the bottom of the sliding shaft, and a plurality of finger grooves are provided on the turntable, and a drone mounting frame is clamped between the two groups of the inclined surface blocks.

[0007] As a preferred technical solution of the present invention, the wheel frame retracting and extending assembly includes a rotating base one, two pulley frames in the same group are fixedly connected to the rotating base one, four rotating bases two are fixedly connected to the bottom plate, the four rotating bases one are rotatably connected to short connecting rods, the four short connecting rods are rotatably connected to rotating shafts, the four rotating bases two are rotatably connected to long connecting rods, the long connecting rods are rotatably connected to the rotating shaft, the rotating shaft is rotatably connected to an annular sleeve, four electric push rods are fixedly connected to the frame body, and the telescopic rods of the electric push rods are fixedly connected to the annular sleeve.

[0008] As a preferred technical solution of the present invention, it also includes a buffer deceleration assembly, which is arranged on the mounting block, and the buffer deceleration assembly includes a ladder frame, four mounting blocks are fixedly connected to two ladder frames on the top, two ladder frames on the same mounting block are a group, each ladder frame is fixedly connected to a buffer base on the top, four pulley frames are fixedly connected to two buffer bases, two buffer bases in the same vertical direction are a group, two buffer bases in the same group are rotatably connected to two buffer connecting rods, two buffer connecting rods on the same buffer base are a group, two groups of buffer connecting rods on the two buffer bases in the same group are rotatably connected, and shock absorbing tubes and sliding rods are respectively fixedly connected to the two buffer bases in the same group, and the sliding rods and The shock absorber tube is slidably connected, and a buffer spring two is connected between the shock absorber tube and one of the buffer bases, and the buffer spring two is sleeved on the sliding rod, and the bottoms of the four sliding rods are fixedly connected to connecting rods, and the bottoms of the four connecting rods are fixedly connected to two inclined plane blocks, and the two inclined plane blocks located on the same connecting rod are a group, and the two inclined plane blocks in the same group are staggered. The two groups of ladder frames are slidably connected with four inclined slot plates, and the inclined slot plates are provided with guide inclined slots. The two inclined slot plates located on the same ladder frame are a group, and the two inclined plane blocks in the same group are respectively located in the guide inclined slots on the two inclined slot plates in the same group. Two brake pads are fixedly connected between the two groups of inclined slot plates, and the two brake pads are symmetrically arranged, and the two brake pads located on the same mounting block are a group.

[0009] Compared with the prior art, the present invention has the following advantages: first, the staff aligns the two sets of inclined blocks with the two limit slots on the drone mounting frame respectively, and then presses the drone mounting frame to complete the installation of the landing gear. When the drone takes off, the four electric push rods will drive the landing wheels to retract. When the drone lands, the electric push rods will drive the landing wheels to swing downward and reset. When the drone lands, the buffer spring will buffer the inertia force of the drone for a while. When the drone is used, the staff will turn the turntable, remove the landing gear and release the turntable. In this way, the landing gear can be quickly installed and disassembled, making the drone assembly more convenient, and preventing the landing gear from loosening due to accidental touching of the turntable. After the drone takes off, the four landing wheels can be retracted to reduce the air resistance of the drone during flight and improve flight efficiency and performance.

[0010] When the drone lands, the two sets of brake pads will contact two of the landing wheels respectively, thereby slowing down the landing wheels through the friction between the brake pads and the landing wheels. When the drone slows down, the brake pads will disengage from the landing wheels. In this way, the inertial force of the drone during landing can be further buffered, and the landing speed of the drone can be braked to slow down, thereby making the drone land more smoothly, optimizing the take-off and landing distances, and reducing the restrictions of the site on the drone. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Schematic diagram of the three-dimensional structure of the present invention.

[0012] Figure 2 A schematic cross-sectional perspective view of the UAV mounting frame of the present invention.

[0013] Figure 3 A schematic diagram of the three-dimensional structure of the turntable of the present invention.

[0014] Figure 4 The present invention Figure 2 Schematic diagram of the enlarged three-dimensional structure of A in the middle.

[0015] Figure 5 A schematic cross-sectional perspective view of the wheel carrier retracting and extending assembly of the present invention.

[0016] Figure 6 The present invention Figure 4 Schematic diagram of the enlarged three-dimensional structure of B in the figure.

[0017] Figure 7 A schematic diagram of a first partially cutaway stereoscopic structure of a quick-install and release assembly of the present invention.

[0018] Figure 8 A schematic diagram of a partially disassembled three-dimensional structure of a buffer deceleration assembly of the present invention.

[0019] Fig. 9 A schematic diagram of a second partially cutaway stereoscopic structure of the quick-install and release assembly of the present invention.

[0020] The markings in the accompanying drawings are: 1-frame, 2-bottom plate, 3-fixed shaft, 31-pulley frame, 32-mounting block, 33-buffer spring 1, 34-lifting wheel, 41-inclined block, 42-connecting pipe, 43-middle shaft, 44-reset spring, 45-connecting frame, 46-arc guide rod, 47-groove plate, 471-sliding shaft, 472-embedded block, 473-ring washer, 474-rotation spring, 48 -turntable, 5-UAV mounting frame, 61-rotating base 1, 62-rotating base 2, 63-short connecting rod, 64-rotating shaft, 65-long connecting rod, 66-annular sleeve, 67-electric push rod, 71-trapezoidal frame, 72-buffering base, 73-buffering connecting rod, 74-shock absorbing tube, 75-sliding rod, 76-buffering spring 2, 761-connecting rod, 77-inclined block, 78-inclined slot plate, 79-brake pad. DETAILED DESCRIPTION

[0021] The standard parts used in the present invention can all be purchased from the market, and special-shaped parts can be customized according to the description in the specification and drawings. The specific connection methods of each part adopt conventional means such as mature bolts, rivets, welding, and bonding in the prior art, which will not be described in detail here.

[0022] Example 1

[0023] A fixed-wing UAV landing gear, such as Figure 1-Figure 9 As shown, it includes a frame body 1, a base plate 2 is welded on the frame body 1, two fixed shafts 3 are fixedly connected to the base plate 2, the two fixed shafts 3 are symmetrically arranged, and two pulley frames 31 are rotatably provided on the two fixed shafts 3, and the two pulley frames 31 located on the same fixed shaft 3 are a group, and a mounting block 32 is slidably connected to the pulley frame 31, a buffer spring 33 is connected between the pulley frame 31 and the mounting block 32 through a hook, and the buffer spring 33 is sleeved on the pulley frame 31, and a lifting wheel 34 is rotatably connected to the mounting block 32, a quick loading and unloading assembly is provided on the frame body 1, and a wheel frame retracting assembly is provided on the base plate 2.

[0024] The quick-loading and disassembly assembly includes an inclined surface block 41, four inclined surface blocks 41 are slidably connected to the frame body 1, and connecting pipes 42 are welded to the four inclined surface blocks 41. Two connecting pipes 42 close to each other form a group, and two inclined surface blocks 41 respectively connected to two connecting pipes 42 of the same group form a group. A central axis 43 is slidably connected between the two connecting pipes 42 of the same group, and a reset spring 44 is connected between the central axis 43 and the two connecting pipes 42 of the same group through a hook. The reset spring 44 is sleeved on the central axis 43. Two connecting frames 45 are connected between the two groups of inclined surface blocks 41 by bolts. The two connecting frames 45 are symmetrically arranged, and arc guide rods 46 are welded to the two connecting frames 45. A groove plate 47 is rotatably connected to the frame body 1, and a groove plate 47 is provided on the groove plate 47. Embedded card slot and two arc grooves, the bottom ends of the two arc guide rods 46 are respectively located in the two arc grooves on the groove plate 47, the groove plate 47 is rotatably connected to the bottom plate 2, a sliding shaft 471 is slidably sleeved on the groove plate 47, the top of the sliding shaft 471 is connected with an embedded card block 472 by bolts, the embedded card block 472 and the embedded card slot on the groove plate 47 are located in the same vertical direction, a ring gasket 473 is rotatably connected in the groove plate 47, the sliding shaft 471 passes through the ring gasket 473, a rotation spring 474 is connected between the ring gasket 473 and the top of the inner wall of the groove plate 47 by a hook, the rotation spring 474 is sleeved on the sliding shaft 471, the bottom of the sliding shaft 471 is connected with a turntable 48 by bolts, a plurality of finger grooves are opened on the turntable 48, and a drone mounting frame 5 is clamped between the two groups of the inclined surface blocks 41.

[0025] The wheel frame retracting and extending assembly includes a rotating base 61, and the two pulley frames 31 of the same group are welded with a rotating base 61, and four rotating bases 2 62 are welded on the bottom plate 2, and the four rotating bases 61 are rotatably connected with short connecting rods 63, and the four short connecting rods 63 are rotatably connected with a rotating shaft 64, and the four rotating bases 2 62 are rotatably connected with long connecting rods 65, and the long connecting rods 65 are rotatably connected to the rotating shaft 64, and the rotating shaft 64 is rotatably connected with an annular sleeve 66, and four electric push rods 67 are connected to the frame body 1 by bolts, and the telescopic rods of the electric push rods 67 are fixedly connected to the annular sleeve 66.

[0026] First, the staff aligns the two groups of inclined surface blocks 41 with the two limit slots on the drone mounting frame 5 respectively, and then presses the drone mounting frame 5, the drone mounting frame 5 will squeeze the two inclined surface blocks 41 of the same group to move in the direction of approaching each other, the movement of the two groups of inclined surface blocks 41 will jointly drive the two connecting frames 45 and the two arc guide rods 46 to move in the direction of approaching each other, the two arc guide rods 46 will squeeze the groove plate 47, the sliding shaft 471 and the turntable 48 to rotate, the movement of the two inclined surface blocks 41 of the same group will also respectively drive the two connecting pipes 42 of the same group to move in the direction of approaching each other, the reset spring 44 will be compressed, and when the two groups of inclined surface blocks 41 are respectively inserted into the two limit slots on the drone mounting frame 5, the reset spring 4 4 will be reset, and the reset spring 44 will drive the two connecting frames 45 and the two arc-surface guide rods 46 to move and reset in the direction away from each other, and the reset of the two arc-surface guide rods 46 will squeeze the groove plate 47 and the rotating plate 48 to rotate in the opposite direction to reset, and the reset of the two connecting frames 45 will drive the two sets of inclined surface blocks 41 to move and reset in the direction away from each other, thereby completing the installation of the landing gear. When the UAV takes off, the four electric push rods 67 will be started at the same time, and the contraction of the telescopic rods of the electric push rods 67 will drive the annular sleeve 66 to move upward, and the upward movement of the annular sleeve 66 will drive the rotating shaft 64 to move upward, and the upward movement of the rotating shaft 64 will drive the short connecting rod 63 and the long connecting rod 65 to swing, and the upward swing of the short connecting rod 63 will drive the pulley frame 31 to swing upward, and the upward swing of the pulley frame will drive The movable mounting block 32, the buffer spring 33 and the landing wheel 34 all swing upward, thereby retracting the landing wheel 34. When the drone lands, the electric push rod 67 drives the landing wheel 34 to swing downward and reset. When the drone lands, the buffer spring 33 buffers the inertia force of the drone. When the drone is used, the staff presses the turntable 48 to move upward. The upward movement of the turntable 48 will drive the sliding shaft 471 to move upward. The upward movement of the sliding shaft 471 will drive the embedded card block 472 to move upward. The rotating spring 474 will be compressed, and the embedded card block 472 will be stuck in the embedded card slot on the slot plate 47. Then the staff will rotate the turntable 48, and the rotation of the turntable 48 will drive the sliding shaft 471, the embedded card block 472 and the slot plate 47 to rotate The rotation of the groove plate 47 will squeeze the two arc-surface guide rods 46 to move towards each other. The movement of the two arc-surface guide rods 46 will drive the two connecting frames 45, the two groups of inclined surface blocks 41 and the two groups of connecting pipes 42 to move towards each other. The reset spring 44 will be compressed again. Then the staff removes the landing gear and loosens the turntable 48. The reset spring 44 will reset again. The reset of the reset spring 44 will drive the two groups of inclined surface blocks 41 to reset, and the rotating spring 474 will reset. The reset of the rotating spring 474 will drive the turntable 48, the sliding shaft 471 and the embedded block 472 to move downward and reset. The embedded block 472 will be out of contact with the groove plate 47. In this way, the landing gear can be quickly installed and disassembled, making the assembly of the drone more convenient.It can also prevent the landing gear from loosening due to accidental touching of the turntable 48. After the drone takes off, the four landing wheels 34 can be retracted to reduce the air resistance of the drone during flight and improve flight efficiency and performance.

[0027] Example 2

[0028] On the basis of Example 1, Figure 4-Figure 8 As shown, a buffer deceleration assembly is also included, and the buffer deceleration assembly is arranged on the mounting block 32. The buffer deceleration assembly includes a ladder frame 71, and the tops of the four mounting blocks 32 are connected to two of the ladder frames 71 by bolts. The two ladder frames 71 located on the same mounting block 32 form a group, and the top of each ladder frame 71 is connected to a buffer base 72 by bolts. The four pulley frames 31 are connected to two buffer bases 72 by bolts, and the two buffer bases 72 located in the same vertical direction form a group. The two buffer bases 72 of the same group are rotatably connected to two buffer connecting rods 73, and the two buffer connecting rods 73 located on the same buffer base 72 form a group. The two groups of buffer connecting rods 73 on the two buffer bases 72 of the same group are rotatably connected, and the two buffer bases 72 of the same group are respectively welded with shock absorbing tubes 74 and sliding rods 75, and the sliding rods 75 and the shock absorbing tubes 74 are slidable. The two bevel blocks 77 are welded on the bottom of the four sliding rods 75, and the two bevel blocks 77 on the same connecting rod 761 are a group, and the two bevel blocks 77 in the same group are staggered. The two groups of ladder frames 71 are slidably connected with four bevel plates 78, and the bevel plates 78 are provided with guide bevel grooves. The two bevel plates 78 on the same ladder frame 71 are a group, and the two bevel blocks 77 in the same group are respectively located in the guide bevel grooves on the two bevel plates 78 in the same group. Two brake pads 79 are connected between the two groups of bevel plates 78 by bolts. The two brake pads 79 are symmetrically arranged, and the two brake pads 79 on the same mounting block 32 are a group.

[0029] When the drone lands, the four pulley frames 31 will move downward under the action of inertia, and the downward movement of the pulley frames 31 will drive two of the buffer bases 72 to move downward, and the downward movement of the buffer base 72 will drive the slide bar 75 to move downward, and the buffer spring 76 will be compressed, and the downward movement of the slide bar 75 will drive the connecting rod 761 to move downward, and the downward movement of the connecting rod 761 will drive the two inclined plane blocks 77 of the same group to move downward, and the downward movement of the two inclined plane blocks 77 of the same group will squeeze the two inclined slot plates 78 of the same group to move away from each other, and the movement of the two groups of inclined slot plates 78 will drive the two brake pads 79 of the same group to move away from each other, and the two groups of brake pads 79 will contact two of the landing wheels 34 respectively, thereby connecting the brake pads 79 to the landing wheels 34. The friction force between the two groups of inclined slot plates 78 will drive the two brake pads 79 to move toward each other and reset, and the brake pads 79 will be out of contact with the landing wheel 34. In this way, the inertial force of the drone during landing can be further buffered, and the landing speed of the drone can be braked and decelerated, so that the drone can land more smoothly, the take-off and landing distances can be optimized, and the restrictions on the drone by the site can be reduced.

[0030] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A fixed-wing UAV landing gear, characterized in that: The invention comprises a frame body (1), a bottom plate (2) fixedly connected to the frame body (1), two fixed shafts (3) fixedly connected to the bottom plate (2), the two fixed shafts (3) being symmetrically arranged, two pulley frames (31) rotatably arranged on the two fixed shafts (3), the two pulley frames (31) located on the same fixed shaft (3) forming a group, a mounting block (32) slidably connected to the pulley frame (31), a buffer spring (33) connected between the pulley frame (31) and the mounting block (32), the buffer spring (33) being sleeved on the pulley frame (31), a lifting wheel (34) rotatably connected to the mounting block (32), a quick assembly assembly being arranged on the frame body (1), and a wheel frame retracting assembly being arranged on the bottom plate (2).

2. A fixed-wing UAV landing gear as claimed in claim 1, characterized in that: The quick-loading and disassembly assembly comprises an inclined surface block (41), four inclined surface blocks (41) are slidably connected to the frame body (1), and the four inclined surface blocks (41) are fixedly connected to a connecting pipe (42), two connecting pipes (42) close to each other form a group, and two inclined surface blocks (41) respectively connected to two connecting pipes (42) of the same group form a group, a central axis (43) is slidably connected between the two connecting pipes (42) of the same group, and a return spring (44) is connected between the central axis (43) and the two connecting pipes (42) of the same group, and the return spring (44) is sleeved on the central axis (43), two connecting frames (45) are fixedly connected between the two groups of inclined surface blocks (41), the two connecting frames (45) are symmetrically arranged, and the two connecting frames (45) are fixedly connected to an arc guide rod (46), and a groove plate (47) is rotatably connected to the frame body (1). The slot plate (47) is provided with an embedded card slot and two arc-shaped slots. The bottom ends of the two arc-shaped guide rods (46) are respectively located in the two arc-shaped slots on the slot plate (47). The slot plate (47) is rotatably connected to the bottom plate (2). A sliding shaft (471) is slidably sleeved on the slot plate (47). An embedded card block (472) is fixedly connected to the top of the sliding shaft (471). The embedded card block (472) and the embedded card slot on the slot plate (47) are located in the same In the vertical direction, a ring washer (473) is rotatably connected inside the groove plate (47), the sliding shaft (471) passes through the ring washer (473), a rotation spring (474) is connected between the ring washer (473) and the top of the inner wall of the groove plate (47), the rotation spring (474) is sleeved on the sliding shaft (471), a rotating disk (48) is fixedly connected to the bottom of the sliding shaft (471), and a drone mounting frame (5) is clamped between the two groups of inclined surface blocks (41).

3. A fixed-wing UAV landing gear as claimed in claim 2, characterized in that: The rotating disk (48) is provided with a plurality of finger grooves.

4. A fixed-wing UAV landing gear as claimed in claim 2, characterized in that: The drone mounting frame (5) is provided with two limit slots, and the top ends of the two groups of card blocks are respectively located in the two limit slots on the drone mounting frame (5).

5. The fixed-wing UAV landing gear according to claim 1, characterized in that: The wheel frame retracting and extending assembly comprises a rotating base one (61), two pulley frames (31) of the same group are fixedly connected with the rotating base one (61), four rotating bases two (62) are fixedly connected with the bottom plate (2), the four rotating bases one (61) are rotatably connected with short connecting rods (63), the four short connecting rods (63) are rotatably connected with a rotating shaft (64), the four rotating bases two (62) are rotatably connected with long connecting rods (65), the long connecting rods (65) are rotatably connected with the rotating shaft (64), the rotating shaft (64) is rotatably connected with an annular sleeve (66), four electric push rods (67) are fixedly connected with the frame body (1), and the telescopic rods of the electric push rods (67) are fixedly connected with the annular sleeve (66).

6. The fixed-wing UAV landing gear according to claim 1, characterized in that: The invention also comprises a buffer deceleration component, wherein the buffer deceleration component is arranged on the mounting block (32), and the buffer deceleration component comprises a ladder frame (71), two of the ladder frames (71) are fixedly connected to the tops of the four mounting blocks (32), the two ladder frames (71) located on the same mounting block (32) form a group, the top of each ladder frame (71) is fixedly connected to a buffer base (72), the four pulley frames (31) are fixedly connected to the two buffer bases (72), and the four pulley frames (31) are located in the same vertical direction. The two buffer bases (72) form a group, and the two buffer bases (72) of the same group are both rotatably connected to two buffer connecting rods (73). The two buffer connecting rods (73) located on the same buffer base (72) form a group, and the two groups of buffer connecting rods (73) on the two buffer bases (72) of the same group are rotatably connected. The two buffer bases (72) of the same group are respectively fixedly connected to a shock absorbing tube (74) and a sliding rod (75). The sliding rod (75) and the shock absorbing tube (74) are slidably connected. A second buffer spring (76) is connected between the shock absorbing tube (74) and one of the buffer bases (72), and the second buffer spring (76) is sleeved on the slide rod (75), wherein the bottoms of the four slide rods (75) are fixedly connected to a connecting rod (761), and the bottoms of the four connecting rods (761) are fixedly connected to two inclined plane blocks (77), and the two inclined plane blocks (77) located on the same connecting rod (761) form a group, and the two inclined plane blocks (77) in the same group are staggered, wherein the two groups of ladder frames ( Four inclined slot plates (78) are slidably connected on the two ladder frames (71), and the inclined slot plates (78) are provided with guiding inclined slots. Two inclined slot plates (78) located on the same ladder frame (71) form a group. The two inclined surface blocks (77) of the same group are respectively located in the guiding inclined slots on the two inclined slot plates (78) of the same group. Two brake pads (79) are fixedly connected between the two groups of inclined slot plates (78), and the two brake pads (79) are symmetrically arranged. The two brake pads (79) located on the same mounting block (32) form a group.

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