A measuring device for engineering design

Abstract

The invention discloses a measuring device for engineering design, which belongs to the technical field of measuring devices and comprises a measuring instrument, wherein a walking component for carrying the measuring instrument is arranged below the bottom of the measuring instrument, and a supporting component for installing the measuring instrument is arranged on the top of the walking component; a protective component for protecting the measuring instrument is arranged above the walking component, and a lifting component for realizing the lifting of the protective component is arranged on the top of the walking component, and the covering protection of the measuring instrument is realized by the rising of the protective component; a buffer component for shock absorbing the measuring instrument is arranged on the protective component, and the penetration of the buffer component through the supporting component is realized by the rising of the protective component; a clamping component for preventing the measuring instrument from shaking is arranged on the supporting component, and the clamping of the clamping component is realized by the rising of the protective component; a limit component for locking the walking component is arranged at the bottom of the walking component, and the locking of the limit component is realized by the descending of the protective component.

Description

Technical Field

[0001] The invention relates to the technical field of measuring devices, in particular to a measuring device used for engineering design. Background Art

[0002] In the field of engineering surveying, measuring instruments are key equipment and are widely used in scenarios such as building construction, bridge construction, and road paving. Engineering surveying often requires frequent movement between multiple measuring points to obtain sufficient data. However, measuring instruments have a precise structure and are particularly afraid of vibration or collision. In order to protect the equipment, the traditional method is to put the measuring instrument into a special packaging box each time it is moved, and then take it out for use after arriving at the target measuring point.

[0003] This repeated packing and unpacking operation is time-consuming and increases the complexity of on-site operations, affecting work efficiency. Secondly, the measuring instrument has a certain weight, and the overall volume of the packaging box is large, so the transportation process is time-consuming and labor-intensive.

[0004] For this purpose, we propose a measuring device for engineering design. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides a measuring device for engineering design, which provides necessary protection and fixing functions in both mobile and use states, ensuring the safety, stability and efficiency of the entire process from transportation to operation of the measuring instrument.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0007] A measuring device for engineering design, comprising a measuring instrument, a walking assembly for carrying the measuring instrument is arranged below the bottom of the measuring instrument, and a supporting assembly for installing the measuring instrument is arranged on the top of the walking assembly;

[0008] A protective component for protecting the measuring instrument is arranged above the walking component, and a lifting component for realizing the lifting of the protective component is arranged on the top of the walking component, so that the measuring instrument is covered and protected by the lifting of the protective component;

[0009] The protection component is provided with a buffer component for reducing the shock of the measuring instrument, and the buffer component penetrates the supporting component by the rising of the protection component;

[0010] The support assembly is provided with a clamping assembly for preventing the measuring instrument from shaking, and the clamping of the clamping assembly is driven by the rise of the protection assembly;

[0011] A limit assembly for locking the traveling assembly is arranged at the bottom of the traveling assembly, and the locking of the limit assembly is achieved by descending the protection assembly.

[0012] As a preferred solution of the measuring device for engineering design described in the present invention, the travel assembly includes a frame, travel wheels and a platform, the platform is horizontally arranged on the top of the frame, and the travel wheels are rotatably arranged on the bottom of the frame.

[0013] As a preferred embodiment of the measuring device for engineering design described in the present invention, the supporting assembly includes a supporting column and a placing table, the supporting column is connected to the top surface of the table plate, the placing table is horizontally arranged on the top of the supporting column, a rotating table is rotatably arranged in the center of the top surface of the placing table, and the measuring instrument is arranged on the top surface of the rotating table.

[0014] As a preferred embodiment of a measuring device for engineering design described in the present invention, the protective component includes a square tube, which is arranged on the top surface of the table and below the measuring instrument. A sleeve hole is provided on the bottom surface of the square tube for the support column to penetrate. When the square tube rises to the top of the support column through the sleeve hole, the square tube covers the measuring instrument. When the square tube descends to the bottom of the support column through the sleeve hole, the square tube exposes the measuring instrument.

[0015] As a preferred solution of a measuring device for engineering design described in the present invention, the protective component also includes a cover plate, which is arranged above the top surface of the measuring instrument, and a fixing frame is connected between the bottom of both sides of the cover plate and the top surface of the table plate, when the square tube rises to the top of the support column through the sleeve hole, the square tube contacts the cover plate and surrounds and covers the measuring instrument, and when the square tube descends to the bottom of the support column through the sleeve hole, the square tube moves away from the cover plate and exposes the measuring instrument, and the front and rear end tops of the cover plate are both arranged on handrails.

[0016] As a preferred solution of a measuring device for engineering design described in the present invention, the lifting assembly includes a connecting sleeve, a screw rod and a sliding rod, the connecting sleeve is connected to the outer walls of both sides of the square tube, the fixing frame is longitudinally provided with a receiving groove facing the outer side surface of the square tube, the connecting sleeve is located inside the receiving groove and is slidably connected up and down, the screw rod is threadedly connected to the connecting sleeve on one side, and the bottom end of the screw rod is rotatably connected to the top surface of the table plate, the top end of the screw rod penetrates the cover plate and is connected to a turning handle, the sliding rod is slidably sleeved on the connecting sleeve on the other side, and the sliding rod is fixedly connected to the top surface of the table plate.

[0017] As a preferred embodiment of the measuring device for engineering design described in the present invention, the buffer assembly includes a support plate, a damper and a shock-absorbing spring, the damper is connected to the inner bottom surface of the square tube, the support plate is horizontally arranged on the top of the damper, the shock-absorbing spring is connected between the bottom of the support plate and the inner bottom surface of the square tube, the top surface of the placement table is provided with a through hole around the rotating table, the through hole is located directly above the support plate, when the square tube rises to the top of the support column through the sleeve hole, the support plate penetrates the through hole, and the top surface of the support plate is higher than the top surface of the rotating table, and the outer edge of the measuring instrument protrudes from the outer edge of the rotating table.

[0018] As a preferred embodiment of the measuring device for engineering design described in the present invention, the clamping assembly includes a clamping plate and a reset spring, square grooves facing the measuring instrument are opened on all four sides of the top surface of the placing table, the lower end of the clamping plate is located inside the square groove and is slidably connected, a guide rod movably penetrating the clamping plate is connected between the inner walls at both ends of the square groove, the reset spring is wound around the outer surface of the guide rod, and the reset spring is connected between the side of the clamping plate facing the measuring instrument and the inner wall at the end of the square groove, the side of the clamping plate facing the measuring instrument is covered with a rubber pad, and the side of the clamping plate away from the measuring instrument is connected with a connecting rod.

[0019] As a preferred solution of a measuring device for engineering design described in the present invention, the connecting rod movably penetrates the square groove and the tail end is located outside the side of the placement table, the tail end of the connecting rod is connected to a push block, the inner side surface of the square tube is a downward slope surface, and when the square tube rises, the inner side surface of the square tube contacts the outer surface of the push block.

[0020] As a preferred embodiment of the measuring device for engineering design described in the present invention, the limit assembly includes a brake pad and an extrusion block, a positioning rod is movably penetrated on the side wall of the frame adjacent to the walking wheel, the brake pad is connected to the end of the positioning rod facing the walking wheel, the end of the positioning rod located inside the frame is connected to the limit block, a supporting spring is connected between the limit block and the inner wall of the frame, the extrusion block is installed inside the frame, and the surface of the extrusion block adjacent to the limit block is an upward slope surface, the top of the extrusion block is connected to a pressure rod, the top of the pressure rod movably penetrates the frame and the platform and is connected to the bottom of the square tube, when the square tube is raised or lowered, the pressure rod is used to lift and lower the extrusion block, and when the extrusion block is lowered, the surface of the extrusion block contacts the surface of the limit block.

[0021] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0022] The protective component covers the measuring instrument by rising, effectively preventing the external environment such as collision, dust, etc. from causing damage to the measuring instrument; the buffer component works with the rising of the protective component, absorbing the vibration during the movement, protecting the measuring instrument, avoiding damage or affecting the subsequent accuracy; the clamping component clamps the measuring instrument when the protective component rises, preventing shaking during the movement and improving transportation stability;

[0023] When the protective component descends, the limit component is driven to lock the travel component to ensure that the device does not move accidentally during measurement; it provides necessary protection and fixing functions in both the moving and use states to ensure the safety, stability and efficiency of the entire process from transportation to operation of the measuring instrument. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a schematic diagram of the structure of a measuring device used in engineering design.

[0025] Figure 2 A schematic diagram of a placement table for a measuring device used in engineering design.

[0026] Figure 3 A schematic diagram of a clamping plate for a measuring device used in engineering design.

[0027] Figure 4 Schematic diagram of a square tube measuring device used in engineering design.

[0028] Figure 5 A schematic diagram of a frame of a measuring device used in engineering design.

[0029] Among them: 1. Table; 2. Frame; 3. Travel wheel; 4. Measuring instrument; 5. Placement table; 6. Square tube; 7. Fixed frame; 8. Cover plate; 9. Handrail; 10. Turn handle; 11. Support column; 12. Rotating table; 13. Clamp; 14. Square groove; 15. Through hole; 16. Return spring; 17. Guide rod; 18. Rubber pad; 19. Connecting rod; 20. Push block; 21. Connecting sleeve; 22. Screw rod; 23. Support spring; 24. Sliding rod; 25. Storage slot; 26. Support plate; 27. Shock-absorbing spring; 28. Damper; 29. ​​Sleeve hole; 30. Pressure rod; 31. Brake pad; 32. Limit block; 33. Extrusion block; 34. Positioning rod. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0031] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0032] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0033] Example

[0034] Please refer to Figures 1 to 5 As shown, the present invention provides a measuring device for engineering design, including a measuring instrument 4, a walking assembly for carrying the measuring instrument 4 is arranged below the bottom of the measuring instrument 4, the walking assembly includes a frame 2, walking wheels 3 and a table 1, the table 1 is horizontally arranged on the top of the frame 2, the walking wheels 3 are rotatably arranged at the bottom of the frame 2, a supporting assembly for installing the measuring instrument 4 is arranged on the top of the walking assembly, the supporting assembly includes a support column 11 and a placement table 5, the support column 11 is connected to the top surface of the table 1, the placement table 5 is horizontally arranged on the top of the support column 11, a rotating table 12 is rotatably arranged at the center of the top surface of the placement table 5, and the measuring instrument 4 is arranged on the top surface of the rotating table 12, the walking assembly realizes convenient transportation of the measuring instrument 4, without repeated packing or additional handling tools, the walking assembly reduces the physical strength required for carrying the measuring instrument 4, and enables the equipment to be easily moved to the target measuring point;

[0035] A protective assembly for protecting the measuring instrument 4 is arranged above the walking assembly, and a lifting assembly for realizing the lifting of the protective assembly is arranged on the top of the walking assembly. The covering protection of the measuring instrument 4 is realized by the lifting of the protective assembly. The lifting assembly includes a connecting sleeve 21, a screw rod 22 and a slide rod 24. The connecting sleeve 21 is connected to the outer walls of both sides of the square tube 6. The fixing frame 7 is longitudinally provided with a receiving groove 25 facing the outer side surface of the square tube 6. The connecting sleeve 21 is located inside the receiving groove 25 and is slidably connected up and down. The screw rod 22 is threadedly connected to the connecting sleeve 21 on one side, and the bottom end of the screw rod 22 is rotatably connected to the top surface of the table 1. The top end of the screw rod 22 penetrates the cover plate 8 and is connected to a turning handle 10. The slide rod 24 is slidably sleeved on the connecting sleeve 21 on the other side, and the slide rod 24 is fixedly connected to the top surface of the table 1. The protective assembly rises during the movement to cover and protect the measuring instrument 4, effectively preventing the external environment such as collision from causing damage to the measuring instrument 4.

[0036] The protection component includes a square tube 6, which is arranged on the top surface of the platform 1 and is located below the measuring instrument 4. The bottom surface of the square tube 6 is provided with a sleeve hole 29 for the support column 11 to penetrate. When the square tube 6 rises to the top of the support column 11 through the sleeve hole 29, the square tube 6 covers the measuring instrument 4. When the square tube 6 descends to the bottom of the support column 11 through the sleeve hole 29, the square tube 6 exposes the measuring instrument 4. The protection component also includes a cover plate 8, which is arranged above the top surface of the measuring instrument 4. A fixing frame 7 is connected between the bottom of both sides of the cover plate 8 and the top surface of the platform 1. When the square tube 6 rises to the top of the support column 11 through the sleeve hole 29, the square tube 6 contacts the cover plate 8 and surrounds and covers the measuring instrument 4. When the square tube 6 descends to the bottom of the support column 11 through the sleeve hole 29, the square tube 6 is away from the cover plate 8 and exposes the measuring instrument 4. The front and rear end tops of the cover plate 8 are both arranged on the handrail 9.

[0037] The protective component is provided with a buffer component for shock absorbing the measuring instrument 4. The buffer component penetrates the supporting component by the rise of the protective component. The buffer component includes a support plate 26, a damper 28 and a shock absorbing spring 27. The damper 28 is connected to the inner bottom surface of the square tube 6. The support plate 26 is horizontally arranged on the top of the damper 28. The shock absorbing spring 27 is connected between the bottom of the support plate 26 and the inner bottom surface of the square tube 6. The top surface of the placing table 5 is penetrated by a through hole 15 around the rotating table 12. The through hole 15 is located at the positive side of the support plate 26. At the top, when the square tube 6 rises to the top of the support column 11 through the sleeve hole 29, the support plate 26 penetrates the through hole 15, and the top surface of the support plate 26 is higher than the top surface of the rotating table 12. The outer edge of the measuring instrument 4 protrudes from the outer edge of the rotating table 12. The buffer component is installed inside the protective component, which is mainly used to absorb vibration and impact, reduce the vibration effect on the measuring instrument 4 during the movement, and ensure the safety of the measuring instrument 4 when moving, especially facing the impact of uneven terrain, to ensure that the internal sensors or optical components of the equipment are not damaged;

[0038] The supporting assembly is provided with a clamping assembly for preventing the measuring instrument 4 from shaking. The clamping assembly is driven by the rise of the protective assembly to achieve clamping. The clamping assembly includes a clamping plate 13 and a reset spring 16. The top surface of the placing table 5 is provided with square grooves 14 facing the measuring instrument 4. The lower end of the clamping plate 13 is located inside the square groove 14 and is slidably connected. A guide rod 17 that movably penetrates the clamping plate 13 is connected between the inner walls at both ends of the square groove 14. The reset spring 16 is wound around the outer surface of the guide rod 17, and the reset spring 16 is connected between the side of the clamping plate 13 facing the measuring instrument 4 and the inner wall at the end of the square groove 14. The side of the plate 13 facing the measuring instrument 4 is covered with a rubber pad 18, and the side of the clamping plate 13 away from the measuring instrument 4 is connected with a connecting rod 19, which movably penetrates the square groove 14 and the tail end is located outside the side of the placing table 5, and the tail end of the connecting rod 19 is connected with a push block 20, and the inner side surface of the square tube 6 is a downward slope surface. When the square tube 6 rises, the inner side surface of the square tube 6 contacts the outer surface of the push block 20. The clamping assembly is used to clamp the measuring instrument 4 to prevent it from shaking or displacement during the movement. It plays a key role in the moving stage and ensures that the measuring instrument 4 is always in a stable state through the clamping method;

[0039] A limit assembly for locking the walking assembly is provided at the bottom of the walking assembly, and the locking of the driving limit assembly is achieved by descending the protection assembly. The limit assembly includes a brake pad 31 and an extrusion block 33. A positioning rod 34 is movably penetrated and provided on the side wall of the frame 2 adjacent to the walking wheel 3. The brake pad 31 is connected to one end of the positioning rod 34 facing the walking wheel 3. One end of the positioning rod 34 located inside the frame 2 is connected to the limit block 32. A support spring 23 is connected between the limit block 32 and the inner wall of the frame 2. The extrusion block 33 is installed inside the frame 2, and the surface of the extrusion block 33 adjacent to the limit block 32 is upward. The top of the extrusion block 33 is connected to the slope surface, and the top of the pressure rod 30 is movably penetrated through the frame 2 and the platform 1 and connected to the bottom of the square tube 6. When the square tube 6 is lifted or lowered, the pressure rod 30 and the extrusion block 33 are lifted or lowered. When the extrusion block 33 is lowered, the surface of the extrusion block 33 contacts the surface of the limit block 32. After reaching the measuring point, the protection component descends to drive the limit component to lock the walking component, ensuring that the equipment is stable and does not move, and realizing rapid switching from the moving state to the measuring state. At the same time, the measurement accuracy is guaranteed. The limit component ensures that the device is firmly positioned after the movement stops, providing basic support for measurement at any time;

[0040] Moving state: the walking component provides the moving ability, the protective component rises to cover the measuring instrument 4, the clamping component clamps the instrument, and the buffer component absorbs the vibration, thus realizing multiple protections for the measuring instrument 4;

[0041] Measuring status: After reaching the measuring point, the protection component descends to drive the limit component to lock the travel component to ensure that the equipment is stable and does not shake during measurement;

[0042] The various components work together to achieve rapid switching of the measuring instrument 4 from the moving state to the measuring state, while ensuring safety during transportation and stability during the measuring process.

[0043] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A measuring device for engineering design, comprising a measuring instrument (4), characterized in that: A walking assembly for carrying the measuring instrument (4) is arranged below the bottom of the measuring instrument (4), and a supporting assembly for installing the measuring instrument (4) is arranged on the top of the walking assembly; A protective component for protecting the measuring instrument (4) is arranged above the walking component, and a lifting component for lifting the protective component is arranged on the top of the walking component, so that the measuring instrument (4) is covered and protected by the lifting of the protective component; The protective component is provided with a buffer component for reducing the shock of the measuring instrument (4), and the buffer component penetrates the supporting component by the rising of the protective component; The supporting component is provided with a clamping component for preventing the measuring instrument (4) from shaking, and the clamping of the clamping component is driven by the rising of the protective component; A limit assembly for locking the traveling assembly is arranged at the bottom of the traveling assembly, and the locking of the limit assembly is achieved by descending the protection assembly.

2. A measuring device for engineering design according to claim 1, characterized in that: The traveling assembly comprises a frame (2), traveling wheels (3) and a platform (1); the platform (1) is horizontally arranged on the top of the frame (2), and the traveling wheels (3) are rotatably arranged on the bottom of the frame (2).

3. A measuring device for engineering design according to claim 2, characterized in that: The supporting assembly comprises a supporting column (11) and a placing table (5), wherein the supporting column (11) is connected to the top surface of the table plate (1), the placing table (5) is horizontally arranged on the top of the supporting column (11), a rotating table (12) is rotatably arranged in the center of the top surface of the placing table (5), and the measuring instrument (4) is arranged on the top surface of the rotating table (12).

4. A measuring device for engineering design according to claim 3, characterized in that: The protective component comprises a square tube (6), the square tube (6) being arranged on the top surface of the platform (1) and located below the measuring instrument (4), the bottom surface of the square tube (6) being provided with a sleeve hole (29) for the support column (11) to penetrate, when the square tube (6) rises to the top of the support column (11) through the sleeve hole (29), the square tube (6) covers the measuring instrument (4), and when the square tube (6) descends to the bottom of the support column (11) through the sleeve hole (29), the square tube (6) exposes the measuring instrument (4).

5. A measuring device for engineering design according to claim 4, characterized in that: The protective assembly also includes a cover plate (8), which is arranged above the top surface of the measuring instrument (4). A fixing frame (7) is connected between the bottom of both sides of the cover plate (8) and the top surface of the platform (1). When the square tube (6) rises to the top of the support column (11) through the sleeve hole (29), the square tube (6) contacts the cover plate (8) and surrounds and covers the measuring instrument (4). When the square tube (6) descends to the bottom of the support column (11) through the sleeve hole (29), the square tube (6) moves away from the cover plate (8) and exposes the measuring instrument (4). The tops of the front and rear ends of the cover plate (8) are both arranged on the handrails (9).

6. A measuring device for engineering design according to claim 5, characterized in that: The lifting assembly comprises a connecting sleeve (21), a screw rod (22) and a sliding rod (24); the connecting sleeve (21) is connected to the outer walls of both sides of the square tube (6); the fixing frame (7) is longitudinally provided with a receiving groove (25) facing the outer side surface of the square tube (6); the connecting sleeve (21) is located inside the receiving groove (25) and is slidably connected up and down; the screw rod (22) is threadedly connected to the connecting sleeve (21) on one side, and the bottom end of the screw rod (22) is rotatably connected to the top surface of the table (1); the top end of the screw rod (22) penetrates the cover plate (8) and is connected to a turning handle (10); the sliding rod (24) is slidably sleeved on the connecting sleeve (21) on the other side, and the sliding rod (24) is fixedly connected to the top surface of the table (1).

7. A measuring device for engineering design according to claim 4, characterized in that: The buffer assembly comprises a support plate (26), a damper (28) and a shock absorbing spring (27); the damper (28) is connected to the inner bottom surface of the square tube (6); the support plate (26) is horizontally arranged on the top of the damper (28); the shock absorbing spring (27) is connected between the bottom of the support plate (26) and the inner bottom surface of the square tube (6); a through hole (15) is provided on the top surface of the placing platform (5) around the rotating platform (12); the through hole (15) is located directly above the support plate (26); when the square tube (6) rises to the top of the supporting column (11) through the sleeve hole (29), the support plate (26) penetrates the through hole (15), and the top surface of the support plate (26) is higher than the top surface of the rotating platform (12); and the outer edge of the measuring instrument (4) protrudes from the outer edge of the rotating platform (12).

8. A measuring device for engineering design according to claim 4, characterized in that: The clamping assembly includes a clamping plate (13) and a reset spring (16). The top surface of the placing table (5) is provided with square grooves (14) facing the measuring instrument (4) on all sides. The lower end of the clamping plate (13) is located inside the square groove (14) and is slidably connected. A guide rod (17) that movably penetrates the clamping plate (13) is connected between the inner walls at both ends of the square groove (14). The reset spring (16) is wound around the outer surface of the guide rod (17), and the reset spring (16) is connected between a side of the clamping plate (13) facing the measuring instrument (4) and the inner wall at the end of the square groove (14). The side of the clamping plate (13) facing the measuring instrument (4) is covered with a rubber pad (18), and the side of the clamping plate (13) away from the measuring instrument (4) is connected with a connecting rod (19).

9. A measuring device for engineering design according to claim 8, characterized in that: The connecting rod (19) movably penetrates the square groove (14) and the tail end is located outside the side of the placing platform (5). The tail end of the connecting rod (19) is connected to a push block (20). The inner side surface of the square tube (6) is a downward slope surface. When the square tube (6) rises, the inner side surface of the square tube (6) contacts the outer surface of the push block (20).

10. A measuring device for engineering design according to claim 4, characterized in that: The limiting assembly comprises a brake pad (31) and an extrusion block (33); a positioning rod (34) is movably penetrated and provided on the side wall of the frame (2) adjacent to the running wheel (3); the brake pad (31) is connected to one end of the positioning rod (34) facing the running wheel (3); one end of the positioning rod (34) located inside the frame (2) is connected to the limiting block (32); a support spring (23) is connected between the limiting block (32) and the inner wall of the frame (2); the extrusion block (33) is installed on the frame (2), and the surface of the extrusion block (33) adjacent to the limit block (32) is an upwardly inclined surface, the top of the extrusion block (33) is connected with a pressure rod (30), the top end of the pressure rod (30) movably penetrates the frame (2) and the platform (1) and is connected to the bottom of the square tube (6), when the square tube (6) is raised or lowered, the pressure rod (30) and the extrusion block (33) are raised or lowered, and when the extrusion block (33) is lowered, the surface of the extrusion block (33) contacts the surface of the limit block (32).

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