A multi-stage lifter

Abstract

The utility model discloses a multistage lifter, one end of first threaded pipe is fixed with support component, first nut is located in first threaded pipe and is passed through thread cooperation with first threaded pipe, transmission component is fixed with first nut, at least one portion of second threaded pipe is located in first threaded pipe, one end of second threaded pipe is fixed with transmission component, the other end of second threaded pipe is fixed with first lifting component, second nut is located in second threaded pipe and is passed through thread cooperation with second threaded pipe, second nut is sleeved on transmission component, and second nut and transmission component are along axial sliding fit, and second nut and transmission component are fixed in circumferential, and hollow shaft is fixed with second nut after passing through first lifting component, first lifting component is sleeved on first threaded pipe, and first lifting component is clearance fit with first threaded pipe, the utility model discloses can realize long distance movement in limited space fast.

Description

Technical Field

[0001] This utility model relates to the field of lifting device technology, specifically to a multi-stage lifting device. Background Technology

[0002] Traditional screw-driven jacks use a worm gear pair that drives a single-stage screw and nut pair. The drive source rotates the worm, which is then slowed down by the worm gear pair. The inner ring of the worm gear has a trapezoidal thread, which meshes with a trapezoidal screw. Without rotating with the worm gear, the trapezoidal screw moves linearly upwards or downwards. This converts rotational motion into linear motion.

[0003] The aforementioned screw-driven elevator has only one stage of screw drive. When the worm gear rotates once, the distance the screw moves is one lead. The distance that the actuator at the screw head can move (effective stroke) is limited by the total length of the screw, which in turn is limited by the size of the installation space.

[0004] In most operating environments, long-distance movement is required within limited installation space. Using traditional lifts either sacrifices the possible movement distance or increases the installation space required. Sacrificing the movement distance significantly reduces the equipment's performance parameters, making it unable to meet market demands. Increasing the installation space makes the equipment bulky and wasteful of resources. Utility Model Content

[0005] This invention provides a multi-stage lifting device, which can quickly achieve long-distance movement within a limited space.

[0006] A multi-stage lifting device includes a support assembly, a first threaded tube, a first nut, and a transmission assembly. One end of the first threaded tube is fixed to the support assembly. The first nut is located inside the first threaded tube and is threadedly engaged with the first threaded tube. The transmission assembly is fixed to the first nut. The device also includes a second threaded tube, a second nut, a hollow shaft, a first lifting assembly that restricts the rotation of the second threaded tube, and a first guide sleeve.

[0007] At least a portion of the second threaded tube is located inside the first threaded tube, one end of the second threaded tube is fixed to the transmission assembly, and the other end of the second threaded tube is fixed to the first lifting assembly;

[0008] The second nut is located inside the second threaded tube and is threadedly engaged with the second threaded tube. The second nut is fitted on the transmission assembly. The second nut and the transmission assembly slide in the axial direction. The second nut and the transmission assembly are fixed in the circumferential direction. The hollow shaft passes through the first lifting assembly and is fixed with the second nut.

[0009] The first lifting component is fitted onto the first threaded tube, and the first lifting component and the first threaded tube are in clearance fit.

[0010] At least a portion of the first guide sleeve is located between the first threaded tube and the second threaded tube. The first guide sleeve is fixed to the first threaded tube, and the first guide sleeve is fixed to the first lifting assembly in the circumferential direction and slides along the axial direction.

[0011] The advantages of this utility model are as follows: In this utility model, a multi-stage lead screw mechanism is nested, and the multi-stage nested lead screw is driven by a driver to convert the rotational motion into linear lifting motion. Compared with conventional lifting devices of the same size, the thread lift angle and lead of the multi-stage lifting device of this utility model can be made larger. In addition, this multi-stage nested lead screw achieves speed multiplication and space optimization, thereby quickly realizing long-distance movement in a limited space. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view of a multi-stage elevator.

[0013] Figure 2 This is a 3D view of the intermediate component.

[0014] Figure 3 This is a 3D view of the second guide tube.

[0015] Figure 4 This is a three-dimensional view of a hollow shaft.

[0016] Figure 5 This is a three-dimensional view of the second lifting inner tube.

[0017] Figure 6 This is a cross-sectional view showing the connection between the multi-stage elevator and the first type of drive.

[0018] Figure 7 This is a three-dimensional view of the second connecting sleeve.

[0019] Figure 8 This is a three-dimensional view of the second lifting outer tube.

[0020] Figure 9 This is a cross-sectional view showing the connection between the multi-stage elevator and the second type of drive.

[0021] Figure 10 This is a cross-sectional view showing the connection between the multi-stage elevator and the third type of drive.

[0022] Figure 11 This is a diagram showing the height-adjustable desk in its lowest position.

[0023] Figure 12 This is a diagram showing the height-adjustable desk after it has been raised to a certain position.

[0024] Labels in the attached diagram:

[0025] Support assembly 1, first threaded tube 2, first nut 3, transmission assembly 4, bearing assembly 4a, transmission shaft 4b, clamping component 4c, head 4d, rod 4e, support sleeve 4f, second threaded tube 5, second nut 6, second nut body 6a, second positioning protrusion 6b, first sleeve 6c, second sleeve 6d, positioning step 6e, first annular groove 6f, second annular groove 6g, hollow shaft 7, assembly groove 7a, first guide sleeve 7b, first lifting tube 8, wear-resistant component 8a, first connecting sleeve 9. Second connecting sleeve 10, inner sleeve 10a, outer sleeve 10b, connecting plate 10c, first spring buckle 10d, second spring buckle 10e, gap space 10f, second lifting inner tube 11, first mounting hole 11a, second lifting outer tube 12, second mounting hole 12a, second guide sleeve 13, outer tube 14, third guide sleeve 15, wear-resistant plate 16, driver 17, motor 17a, worm gear transmission mechanism 17b, box 17c, planetary gear reducer 17d, connecting seat 17e, desktop A, bracket B. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] like Figures 1 to 8 The multi-stage lifter in this embodiment includes a support assembly 1, a first threaded tube 2, a first nut 3, a transmission assembly 4, a second threaded tube 5, a second nut 6, a hollow shaft 7, a first lifting assembly that restricts the rotation of the second threaded tube 5, and a first guide sleeve 7b. The details of each part and their relationships are described below. This invention can be applied to lifting equipment (such as lifting tables, lifting platforms, lifting chairs, etc.) to form single-column (single-column) or multi-column (multi-column) lifting equipment with two or more multi-stage lifters.

[0029] The first threaded tube 2 is an internally threaded tube. One end of the first threaded tube 2 is fixed to the support component 1. The support component 1 is provided with a boss. One end of the first threaded tube 2 is fitted onto the boss. The first threaded tube 2 is preferably fixed to the support component 1 by welding. When in use, the first threaded tube 2 cannot move along the axial direction of the support component 1, nor can it rotate along the circumferential direction of the support component 1.

[0030] The first nut 3 is located inside the first threaded tube 2 and is threadedly engaged with the first threaded tube 2. The cross-section of the inner hole on the first nut 3 is polygonal. When a circumferential force is applied to the first nut 3 to rotate it, the first nut 3 can move axially along the first threaded tube 2.

[0031] The transmission assembly 4 is fixed to the first nut 3, and the second nut 6 is sleeved on the transmission assembly 4. The second nut 6 and the transmission assembly 4 slide in the axial direction. The second nut 6 and the transmission assembly 4 are fixed in the circumferential direction. The transmission assembly 4 includes a transmission unit and a bearing assembly 4a. The bearing assembly 4a is fixed to one end of the second threaded tube 5. The bearing assembly 4a consists of a bearing housing and a bearing. The bearing is located inside the bearing housing, and the outer ring of the bearing is fixed to the bearing housing. The first nut 3 is axially limited by the bearing assembly 4a.

[0032] The transmission unit passes through the bearing assembly 4a and the first nut 3. The transmission unit includes a transmission shaft 4b, an intermediate component, and a clamping component 4c. One end of the transmission shaft 4b passes through the second nut 6, which slides axially with the transmission shaft 4b and is fixed circumferentially with the transmission shaft 4b.

[0033] The intermediate component includes a head 4d and a rod 4e. The other end of the drive shaft 4b is fixed to the head 4d. One end of the head 4d is provided with an internal hexagonal hole, and a radial hole is also provided on the circumference of the head 4d. The drive shaft 4b is a hexagonal prism drive shaft. The end of the drive shaft 4b is provided with a radial through hole. The end of the drive shaft 4b is inserted into the internal hexagonal hole on the head 4d. A locking component is used to engage with the radial hole on the head 4d and the radial through hole on the drive shaft 4b to lock the drive shaft 4b and the head 4d into one piece.

[0034] The other end of the head 4d is fixed to one end of the rod 4e. The head 4d and the rod 4e are integrally formed, for example, by casting. The other end of the rod 4e passes through the bearing assembly 4a and the first nut 3 and is connected to the clamping component 4c. The bearing assembly 4a and the first nut 3 are clamped between the head 4d and the clamping component 4c.

[0035] The rod 4e is preferably composed of a polygonal segment and a threaded segment. The polygonal segment on the rod 4e mates with the inner hole on the first nut 3. The clamping component 4c can be a nut, a retaining ring, or a locking pin. In this embodiment, the clamping component 4c is preferably a nut. The threaded segment on the rod 4e is threadedly connected to the clamping component 4c.

[0036] The transmission unit also includes a support sleeve 4f, which is fixed to the transmission shaft 4b and is located inside the hollow shaft 7 and slides with it. Thus, one end of the transmission unit is supported by the first nut 3, and the other end is supported by the support sleeve 4f.

[0037] The second threaded tube 5 is an internally threaded tube. A portion of the second threaded tube 5 is located inside the first threaded tube 2. One end of the second threaded tube 5 is fixed to the transmission assembly 4, and the other end of the second threaded tube 5 is fixed to the first lifting assembly. One end of the second threaded tube 5 is fixed to the bearing seat in the bearing assembly 4a, and the bearing assembly 4a provides support for one end of the second threaded tube 5.

[0038] The second nut 6 is located inside the second threaded tube 5 and is threadedly engaged with the second threaded tube 5. The second nut 6 includes a second nut body 6a and a second guide tube. The second nut body 6a is fixed to the second guide tube. The transmission component 4 passes through the second guide tube. The second guide tube and the transmission component 4 are slidably engaged along the axial direction. The second guide tube and the transmission component 4 are fixed in the circumferential direction. This relationship allows the second guide tube and the transmission component 4 to transmit torque and also to generate relative movement between them along the axial direction.

[0039] In the transmission assembly 4, the drive shaft 4b is a hexagonal prism, and the axial through-tube on the second guide tube is an internal hexagonal hole. Therefore, the hexagonal drive shaft 4b passes through the internal hexagonal hole on the second guide tube, allowing the second guide tube and the transmission assembly 4 to slide along the axial direction and be fixed in the circumferential direction. The second guide tube and the transmission assembly 4 can also use a spline fit to achieve both torque transmission and relative axial movement between the two.

[0040] The second guide tube includes a first sleeve 6c, a second sleeve 6d, and a retaining ring (not shown in the figure). The first sleeve 6c and the second sleeve 6d are fixed together. A positioning step 6e is provided on the circumferential surface of the second sleeve 6d. A first annular groove 6f is provided on the first sleeve 6c. The first sleeve 6c is prismatic in shape. The inner hole of the second nut body 6a is a polygonal hole (e.g., an internal hexagonal hole). The first sleeve 6c passes through the second nut body 6a. One end of the second nut body 6a is axially limited by the positioning step 6e. The retaining ring cooperates with the first annular groove 6f to axially limit the other end of the second nut body 6a.

[0041] The hollow shaft 7 is fixed to the torque output end of the driver 17. After passing through the first lifting assembly, the hollow shaft 7 is fixed to the second nut 6. The circumferential surface of the second guide tube is provided with a second positioning protrusion 6b for circumferential fixation with the hollow shaft 7. The second positioning protrusion 6b is provided on the second sleeve 6d. The hollow shaft 7 is provided with an assembly groove 7a. The second sleeve 6d is also provided with a second annular groove 6g. The inner wall of the hollow shaft 7 is provided with an annular protrusion. After the hollow shaft 7 is fitted onto the second sleeve 6d, the second positioning protrusion 6b and the assembly groove 7a combine to fix the hollow shaft 7 and the second sleeve 6d in the axial direction. The annular protrusion and the second annular groove 6g combine to fix the hollow shaft 7 and the second sleeve 6d in the circumferential direction.

[0042] The outer circumferential surface of the hollow shaft 7 is rolled along the circumferential direction to form an annular groove on the outer circumferential surface of the hollow shaft 7, and the annular protrusion is formed on the inner circumferential surface of the hollow shaft 7. The annular protrusion enters the second annular groove 6g, thereby fixing the hollow shaft 7 and the second sleeve 6d in the axial direction.

[0043] It also includes a first lifting tube 8, which cooperates with a first lifting assembly to fix the first lifting tube 8 and the first lifting assembly in the circumferential direction, and the first lifting tube 8 and the first lifting assembly slide in the axial direction, with at least a portion of the first threaded tube 2 located inside the first lifting tube 8.

[0044] The first lifting assembly is fitted onto the first threaded tube 2, with a clearance fit between the first lifting assembly and the first threaded tube 2. The first lifting assembly includes a first connecting sleeve 9 and a second lifting inner tube 11. The first connecting sleeve 9 is fixed to the other end of the second threaded tube 5, and one end of the second lifting inner tube 11 is fixed to the first connecting sleeve 9. The second lifting inner tube 11 is in clearance fit with the first threaded tube 2. Because the first lifting assembly is restricted from rotating in the circumferential direction, and the second threaded tube 5 is fixedly connected to the first lifting assembly, the second threaded tube 5 cannot rotate either.

[0045] The first lifting assembly also includes a second connecting sleeve 10 and a second lifting outer tube 12. The other end of the second lifting inner tube 11 is fixed to the second connecting sleeve 10. The second lifting outer tube 12 surrounds the second lifting inner tube 11 and is fixed to the second connecting sleeve 10.

[0046] In this embodiment, the second connecting sleeve 10 includes an inner sleeve 10a, an outer sleeve 10b, and a connecting plate 10c. The inner sleeve 10a is located inside the outer sleeve 10b, and the connecting plate 10c is located between the inner sleeve 10a and the outer sleeve 10b. One end of the connecting plate 10c is fixed to the inner sleeve 10a, and the other end of the connecting plate 10c is fixed to the outer sleeve 10b. The second lifting inner tube 11 is inserted into the inner sleeve 10a and fixed to the inner sleeve 10a. The outer sleeve 10b is inserted into the second lifting outer tube 12 and fixed to the second lifting outer tube 12. Thus, a space 10f is formed between the second lifting inner tube 11 and the second lifting outer tube 12. The first lifting tube 8 is inserted into the space 10f. When the multi-stage lifting device is performing lifting operations, it can be seen from the outside that both the first lifting tube 8 and the second lifting outer tube 12 will move up and down, thus visually demonstrating the layered effect of multi-stage lifting.

[0047] In this embodiment, the inner sleeve 10a has a first spring buckle 10d on its side wall, and the second lifting inner tube 11 has a first mounting hole 11a. The first spring buckle 10d engages with the first mounting hole 11a, thereby fixing the inner sleeve 10a to the second lifting inner tube 11. The outer sleeve 10b has a second spring buckle 10e on its side wall, and the second lifting outer tube 12 has a second mounting hole 12a. The second spring buckle 10e engages with the second mounting hole 12a, thereby fixing the outer sleeve 10b to the second lifting outer tube 12.

[0048] In this embodiment, the first lifting assembly further includes a second guide sleeve 13, which is fixed to the second lifting outer tube 12. The first lifting tube 8 passes through the second guide sleeve 13 and is clearance-fitted with it. A wear-resistant component 8a is fixed on the outer circumferential surface of the first lifting tube 8. The wear-resistant component 8a is slidably fitted with the second lifting outer tube 12. The second guide sleeve 13 and the wear-resistant component 8a can be made of self-lubricating and wear-resistant materials, such as polytetrafluoroethylene or POM. The second guide sleeve 13 and the wear-resistant component 8a both separate the first lifting tube 8 and the second lifting outer tube 12, and guide the first lifting tube 8 when it rises or falls.

[0049] A portion of the first guide sleeve 7b is located between the first threaded tube 2 and the second threaded tube 5. The first guide sleeve 7b is fixed to the other end of the first threaded tube 2. The first guide sleeve 7b can be made of a self-lubricating and wear-resistant material, such as polytetrafluoroethylene (PTFE) or POM. The other portion of the first guide sleeve 7b is located outside the first threaded tube 2. The other portion of the first guide sleeve 7b is fixed circumferentially to the first lifting assembly and slides axially. The other portion of the first guide sleeve 7b is fixed circumferentially to the second lifting inner tube 11 in the first lifting assembly, for example, through a spline fit, or the other portion of the first guide sleeve 7b is prismatic, and the inner hole of the second lifting inner tube 11 is a polygonal hole. The first guide sleeve 7b separates the first threaded tube 2 and the second threaded tube 5, and also guides the second threaded tube 5 when it is raised or lowered.

[0050] This embodiment also includes a buffer pad 7c, which is sleeved on the hollow shaft 7 and fixed to the hollow shaft 7. The buffer pad 7c rises and falls with the hollow shaft 7. The buffer pad 7c is located at the end of the hollow shaft 7. When the first connecting sleeve 9 rises to the highest position and collides with the buffer pad 7c, the buffer pad 7c buffers the first connecting sleeve 9.

[0051] This embodiment also includes an outer tube 14 and a third guide sleeve 15. The outer tube 14 surrounds the first lifting assembly, with one end fixed to the support assembly 1. The third guide sleeve 15 is fixed to the other end of the outer tube 14. The first lifting assembly passes through the third guide sleeve 15 and is in clearance fit with it. A wear-resistant plate 16 is fixed on the first lifting assembly, and the wear-resistant plate 16 slides against the inner wall of the outer tube 14. The third guide sleeve 15 and the wear-resistant plate 16 both separate the outer tube 14 and the second lifting outer tube 12, preventing the second lifting outer tube 12 from rotating due to the restriction imposed by the third guide sleeve 15 and the outer tube 14, and also provide guidance when the second lifting outer tube 12 rises or falls. The third guide sleeve 15 and the wear-resistant plate 16 can be made of self-lubricating and wear-resistant materials, such as polytetrafluoroethylene (PTFE) or POM.

[0052] This embodiment also includes a driver 17, whose torque output end is fixed to the hollow shaft 7, and the driver 17 is connected to the first rising tube 8. The driver 17 in this embodiment consists of a motor 17a, a worm gear transmission mechanism 17b, and a housing 17c. The motor 17a and the worm gear transmission mechanism 17b are located within the housing 17c, which is fixed to the first rising tube 8 and located outside the first rising tube 8. The output end of the motor 17a is fixed to the input end of the worm gear transmission mechanism 17b, and the output end of the worm gear transmission mechanism 17b is fixed to the hollow shaft 7. The worm gear transmission mechanism 17b is used to reduce the output speed of the motor 17a and increase the torque.

[0053] Example 2

[0054] like Figure 9 As shown, this embodiment differs from Embodiment 1 in that the driver 17 consists of a motor 17a, a planetary gear reducer 17d, and a connecting seat 17e. Both the motor 17a and the planetary gear reducer 17d are located inside the first rising tube 8, while the connecting seat 17e is located inside or outside the first rising tube 8. The connecting seat 17e is fixed to the first rising tube 8, and the motor 17a is fixed to the connecting seat 17e. The torque output end of the motor 17a is fixed to the torque input end of the planetary gear reducer 17d, and the torque output end of the planetary gear reducer 17d is fixed to the hollow shaft 7. The planetary gear reducer 17d is used to reduce the output speed of the motor 17a and increase the torque.

[0055] Example 3

[0056] like Figure 10 As shown, this embodiment differs from Embodiment 1 in that it further includes a gearbox, which comprises a housing 18, a driving gear 19, a first driven gear 20, and a second driven gear 21. The driving gear 19, the first driven gear 20, and the second driven gear 21 are all installed inside the housing 18. The driving gear 19 is connected to the torque output shaft of the motor (the motor is in...). Figure 10 (Not shown in the image) The motor is located outside the housing 18. The first driven gear 20 and the second driven gear 21 are respectively meshed with the driving gear 19. The first driven gear 20 is connected to the hollow shaft 7. If the lifting device of this embodiment is used for a double-column lifting device, the second driven gear 21 is connected to a transmission shaft, and the transmission shaft is then connected to the second driven gear 21 in another multi-stage lifting device. In this way, power can be output to two multi-stage lifting devices through one motor, so that the two multi-stage lifting devices can lift and lower synchronously.

[0057] like Figure 11As shown, the height-adjustable desk of this utility model includes a desktop A and a support B, with the desktop A fixed to the support B. It also includes a multi-stage lifter as described in any of the above embodiments, which is fixedly connected to the support B. For example, when the multi-stage lifter of Embodiment 1 is used and fixed to the support, the housing 17c of the multi-stage lifter is fixed to the support B. When the multi-stage lifter of Embodiment 2 is used and fixed to the support, the first lifting tube 8 or connecting seat 17e of the multi-stage lifter is fixed to the support B.

[0058] Combination Figures 11 to 12 The working process of the height-adjustable desk is explained as follows:

[0059] When the driver 17 rotates forward, the torque output by the driver 17 is transmitted to the hollow shaft 7, causing the hollow shaft 7 to rotate. The hollow shaft 7 drives the second guide tube in the second nut 6 to rotate. The second guide tube transmits the torque to the second nut body 6a and the drive shaft 4b respectively, thereby causing the second nut body 6a and the drive shaft 4b to rotate. Since the second threaded tube 5 is restricted in the circumferential direction and cannot rotate, when the second nut body 6a rotates, through the threaded engagement between the second nut body 6a and the second threaded tube 5, the second nut body 6a moves upward relative to the second threaded tube 5, thereby driving the hollow shaft 7 to move upward. The hollow shaft 7 drives the driver 17 to rise. Since the first lifting tube 8 is fixed to the driver 17, the first lifting tube 8 rises with the driver 17. The desktop A and the bracket B also rise. The first stage (first lifting tube 8) of the multi-stage lift can be seen rising from the outside of the lifting table.

[0060] When the drive shaft 4b rotates, it transmits torque to the first nut 3 through the intermediate component. Since the first threaded tube 2 is restricted in the circumferential direction and cannot rotate, the threaded engagement between the first nut 3 and the first threaded tube 2 causes the first nut 3 to rise relative to the first threaded tube 2. The transmission assembly 4 rises along with the first nut 3. Because the transmission assembly 4 is fixed to the second threaded tube 5, and the second threaded tube 5 is fixed to the first connecting sleeve 9, and the first connecting sleeve 9 is fixed to the second connecting sleeve 10 via the second lifting inner tube 11, and the second connecting sleeve 10 is fixed to the second lifting outer tube 12, when the second threaded tube 5 rises along with the transmission assembly 4, the first connecting sleeve 9, the second lifting inner tube 11, the second connecting sleeve 10, and the second lifting outer tube 12 all rise. The second stage (second lifting outer tube 12) of the multi-stage lifter can be seen rising from outside the lifting table. During the rising process of the second threaded tube 5, the threaded engagement between the second threaded tube 5 and the second nut body 6a drives the second nut body 6a to rise, thereby accelerating the rising speed of the hollow shaft 7.

[0061] When the height-adjustable table descends, the control drive 17 can be reversed. Its working process is the opposite of the rising process, which will not be described in detail here.

[0062] In this invention, the formula for calculating the lifting speed is:

[0063] In the above formula, n is the input speed, p is the pitch of the threaded pipe, and i is the reduction ratio.

[0064] In the structure of this utility model, due to the increased pitch of the nested screw mechanism, according to the above formula, under the same rotational speed n and reduction ratio i, the increased pitch p of the threaded tube leads to an increased lifting speed V. Therefore, this utility model can improve the lifting speed.

Claims

1. A multi-stage lifting device, comprising a support assembly (1), a first threaded tube (2), a first nut (3), and a transmission assembly (4), wherein one end of the first threaded tube (2) is fixed to the support assembly (1), the first nut (3) is located inside the first threaded tube (2) and is threadedly engaged with the first threaded tube (2), and the transmission assembly (4) is fixed to the first nut (3), characterized in that, It also includes a second threaded tube (5), a second nut (6), a hollow shaft (7), a first lifting assembly that restricts the rotation of the second threaded tube (5), and a first guide sleeve (7b); At least a portion of the second threaded tube (5) is located inside the first threaded tube (2), one end of the second threaded tube (5) is fixed to the transmission assembly (4), and the other end of the second threaded tube (5) is fixed to the first lifting assembly; The second nut (6) is located inside the second threaded tube (5) and is threadedly engaged with the second threaded tube (5). The second nut (6) is sleeved on the transmission assembly (4). The second nut (6) and the transmission assembly (4) are axially slidingly engaged. The second nut (6) and the transmission assembly (4) are fixed in the circumferential direction. The hollow shaft (7) passes through the first lifting assembly and is fixed with the second nut (6). The first lifting assembly is fitted onto the first threaded tube (2), and the first lifting assembly and the first threaded tube (2) are in clearance fit. At least a portion of the first guide sleeve (7b) is located between the first threaded tube (2) and the second threaded tube (5). The first guide sleeve (7b) is fixed to the first threaded tube (2). The first guide sleeve (7b) is fixed to the first lifting assembly in the circumferential direction and slides in the axial direction.

2. The multi-stage lifting device according to claim 1, characterized in that, The transmission assembly (4) includes a transmission unit and a bearing assembly (4a). The bearing assembly (4a) is fixed to one end of the second threaded tube (5), and the transmission unit passes through the bearing assembly (4a) and the first nut (3).

3. A multi-stage lifting device according to claim 2, characterized in that, The transmission unit includes a transmission shaft (4b), an intermediate component, and a clamping component (4c). One end of the transmission shaft (4b) passes through a second nut (6). The intermediate component includes a head (4d) and a rod (4e). The other end of the transmission shaft (4b) is fixed to the head (4d). The head (4d) is fixed to one end of the rod (4e). The other end of the rod (4e) passes through a bearing assembly (4a) and a first nut (3) and is connected to the clamping component (4c). The bearing assembly (4a) and the first nut (3) are clamped between the head (4d) and the clamping component (4c).

4. A multi-stage lifting device according to claim 3, characterized in that, The transmission unit also includes a support sleeve (4f), which is fixed to the transmission shaft (4b). The support sleeve (4f) is located inside the hollow shaft (7) and slides with the hollow shaft (7).

5. A multi-stage lifting device according to claim 1, characterized in that, The second nut (6) includes a second nut body (6a) and a second guide tube. The second nut body (6a) is fixed to the second guide tube. The transmission assembly (4) passes through the second guide tube. The second guide tube and the transmission assembly (4) slide in the axial direction. The second guide tube and the transmission assembly (4) are fixed in the circumferential direction. The circumferential surface of the second guide tube is provided with a second positioning protrusion (6b) for circumferential fixing with the hollow shaft (7).

6. A multi-stage lifting device according to claim 5, characterized in that, The second guide tube includes a first sleeve (6c), a second sleeve (6d), and a retaining ring. The first sleeve (6c) and the second sleeve (6d) are fixed together. The second sleeve (6d) has a positioning step (6e) on its circumference. The first sleeve (6c) has a first annular groove (6f). The first sleeve (6c) is prismatic in shape. The inner hole of the second nut body (6a) is a polygonal hole. The first sleeve (6c) passes through the second nut body (6a). One end of the second nut body (6a) is limited by the positioning step (6e). The retaining ring cooperates with the first annular groove (6f) to axially limit the other end of the second nut body (6a).

7. A multi-stage lifting device according to claim 1, characterized in that, The first lifting assembly includes a first connecting sleeve (9) and a second lifting inner tube (11). The first connecting sleeve (9) is fixed to the other end of the second threaded tube (5), and one end of the second lifting inner tube (11) is fixed to the first connecting sleeve (9). The second lifting inner tube (11) and the first threaded tube (2) are in clearance fit.

8. A multi-stage lifting device according to claim 7, characterized in that, The first lifting assembly also includes a second connecting sleeve (10) and a second lifting outer tube (12). The other end of the second lifting inner tube (11) is fixed to the second connecting sleeve (10). The second lifting outer tube (12) surrounds the second lifting inner tube (11) and is fixed to the second connecting sleeve (10).

9. A multi-stage lifting device according to claim 8, characterized in that, The second connecting sleeve (10) includes an inner sleeve (10a), an outer sleeve (10b), and a connecting plate (10c). The inner sleeve (10a) is located inside the outer sleeve (10b), and the connecting plate (10c) is located between the inner sleeve (10a) and the outer sleeve (10b). One end of the connecting plate (10c) is fixed to the inner sleeve (10a), and the other end of the connecting plate (10c) is fixed to the outer sleeve (10b). The second lifting inner tube (11) is inserted into the inner sleeve (10a) and fixed to the inner sleeve (10a). The outer sleeve (10b) is inserted into the second lifting outer tube (12) and fixed to the second lifting outer tube (12).

10. A multi-stage lifting device according to claim 9, characterized in that, The inner sleeve (10a) has a first spring buckle (10d) on its side wall, and the second lifting inner tube (11) has a first mounting hole (11a). The first spring buckle (10d) is engaged with the first mounting hole (11a). The outer sleeve (10b) has a second spring buckle (10e) on its side wall, and the second lifting outer tube (12) has a second mounting hole (12a). The second spring buckle (10e) is engaged with the second mounting hole (12a).

Images