A main frame support structure of a balance pull hook device

Abstract

The utility model discloses a main frame support structure of balance pull hook device. It includes: crossbeam, stand, set up in the both sides of crossbeam, the top of stand is provided with the crossbeam connecting groove that matches with crossbeam, the top of stand is installed on crossbeam through crossbeam connecting groove and is connected with its left and right slide, locking device no.

Description

Technical Field

[0001] This utility model relates to the field of medical device technology, and in particular to a main frame support structure for a balance hook device. Background Technology

[0002] The minimally invasive resection technique for mediastinal tumors via the xiphoid approach is becoming increasingly mature. However, due to the narrow space in the anterior and posterior mediastinum behind the sternum, the operating space is small, and the surgery is quite difficult. It is necessary to elevate the sternum to expand the mediastinal space, expose the mediastinum, increase the operating space, reduce the difficulty of the surgery, and increase the safety of the surgery.

[0003] Chinese Patent Grant Announcement No.: CN 221830680 U, authorized announcement date 2024.10.15, discloses a sternal retractor device for mediastinal exposure, including a main frame support, the main frame support is "door" shaped, including two vertical rods and one horizontal rod, the two ends of the horizontal rod are respectively connected to the upper ends of the two vertical rods, the bottom of the vertical rods are connected to bed edge fixators, the horizontal rod is slidably connected to a second fixator, the second fixator is connected to a horizontally arranged cantilever beam, the cantilever beam is slidably connected to two third fixators, the third fixators are connected to a liftable slide rod, the bottom of the slide rod is connected to a hook assembly, the vertical rods and the horizontal rod are connected by a quick-release lock, the quick-release lock includes a first clamp and a second clamp, the first clamp and the second clamp are annular parts with an opening, the two sides of the opening are respectively provided with clamping arms, the clamping arms of the first clamp are provided with through holes, the clamping arms of the second clamp are provided with threaded holes, the quick-release rod passes through the through hole of the first clamp and is threaded into the threaded hole of the second clamp, the vertical rod is set in the second clamp, and the horizontal rod is set in the first clamp. The shortcomings of the aforementioned patent are as follows: Since the first and second clamps share a single quick-release lever for tension adjustment, both clamps can only be simultaneously loosened or tightened by the lever. When the user needs to adjust the height of the crossbar, they must rotate the quick-release lever to loosen the second clamp, thus adjusting the crossbar height vertically. However, while rotating the lever, the first clamp, which fixes the distance between the two vertical bars, is also loosened. This makes it easy for the user to accidentally touch the vertical bars during the adjustment of the crossbar height, causing a change in the distance between the two vertical bars. Similarly, when adjusting the distance between the two vertical bars, the user may accidentally touch the crossbar, causing a change in the crossbar height. In other words, this device struggles to maintain a constant distance between the two vertical bars when adjusting the crossbar height alone, and it also struggles to maintain a constant crossbar height when adjusting the distance between the two vertical bars alone, making adjustment difficult.

[0004] In summary, there is a need for a main frame support structure for a balance hook device that allows for convenient individual adjustment of the height of the horizontal bar or the distance between the two vertical bars. Utility Model Content

[0005] This invention aims to overcome the shortcomings of existing balance hook devices, which are difficult to maintain a constant distance between the two vertical bars when adjusting the height of the horizontal bar alone, and difficult to maintain a constant height of the horizontal bar when adjusting the distance between the two vertical bars alone, resulting in significant adjustment difficulties. This invention provides a main frame support structure for a balance hook device that allows for convenient individual adjustment of the height of the horizontal bar or the distance between the two vertical bars.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A main frame support structure for a balance hook device includes: beam; The columns are provided on both sides of the crossbeam. The top of the column is provided with a crossbeam connecting groove that matches the crossbeam. The top of the column is installed on the crossbeam through the crossbeam connecting groove and is slidably connected to it to the left and right. Locking device one is installed at the connection between the column and the beam; A clamp is provided at the bottom of the column, and the clamp is provided with a column connection hole that matches the column. The bottom of the column is placed in the column connection hole and is slidably connected to it. A locking device II corresponding to the column is installed at the column connection hole.

[0007] The clamp is equipped with clamping blocks to hold the edge of the operating table. When adjusting the distance between the two uprights, the second locking device can be used to fix the uprights and clamp relative to each other, preventing the uprights from sliding up and down and ensuring the height of the crossbeam remains constant. Then, the uprights can slide left and right on the crossbeam through their connecting slots, allowing for individual adjustment of the distance between the two uprights. After adjustment, the first locking device can be used to fix the crossbeam and uprights relative to each other again. Similarly, when adjusting the height of the crossbeam, the first locking device can be used to fix the crossbeam and uprights relative to each other, preventing the uprights from sliding left and right on the crossbeam and ensuring the distance between the two uprights remains constant. Then, the uprights can slide up and down within the upright connecting holes on the clamp, allowing for individual adjustment of the crossbeam height or the distance between the two uprights. The structure is simple, easy to adjust, and easy to operate, facilitating individual adjustment of the crossbeam height or the distance between the two uprights.

[0008] Preferably, the crossbeam connecting groove includes a connecting groove opening, a connecting groove bottom surface, a connecting groove sidewall one, and a connecting groove sidewall two. A screw hole is provided on the connecting groove sidewall one. The locking device one includes a tightening screw threadedly connected to the screw hole one. One end of the tightening screw one is placed inside the crossbeam connecting groove and a pressure plate is fixed thereon. The other end of the tightening screw one is placed outside the crossbeam connecting groove and a knob is fixed thereon. During fixing, the user can tighten the tightening screw one to press it against the crossbeam, thus achieving relative fixation between the crossbeam and the column. The structure is simple and the operation is convenient. The knob design allows the user to apply force to tighten the tightening screw one by holding the knob, improving operational convenience. The pressure plate design increases the contact area between the tightening screw one and the crossbeam, reducing local pressure and protecting the surface of the crossbeam from damage.

[0009] Preferably, a limiting stop is fixed on the second sidewall of the connecting groove, facing the first sidewall of the connecting groove. The limiting stop is located at the opening of the connecting groove. The distance between the side of the limiting stop facing the bottom of the connecting groove and the bottom of the connecting groove is adapted to the longitudinal section height of the crossbeam. The sum of the distance between the side of the limiting stop near the first sidewall of the connecting groove and the first sidewall of the connecting groove, and the longitudinal section width of the crossbeam, is adapted to the distance between the first sidewall of the connecting groove and the second sidewall of the connecting groove. This blocking design of the limiting stop at the opening of the connecting groove allows the crossbeam to be inserted into the crossbeam connecting groove either from the opening or from the side of the crossbeam connecting groove, improving assembly convenience. After the crossbeam is installed into the crossbeam connecting groove on the column, the crossbeam is pressed against the second side wall of the connecting groove by tightening the screw. Combined with the blocking effect of the limiting edge at the top of the second side wall of the connecting groove, the fixing effect of the crossbeam in the crossbeam connecting groove is greatly improved, and the possibility of the crossbeam coming loose from the crossbeam connecting groove during the operation is avoided.

[0010] Preferably, the crossbeam includes a first beam segment, a beam segment connector, and a second beam segment. The beam segment connector is positioned between the first and second beam segments. Both ends of the beam segment connector are provided with beam segment connecting pins, which are hinged to the connector. One end of the connecting pin is inserted and fixed to the end of the first beam segment, and the other end is inserted and fixed to the end of the second beam segment. A rotation limiting rib is also fixed to the beam segment connector, positioned on the side of the connecting pin. This relative rotation design between the first and second beam segments facilitates the storage and organization of the crossbeam, saving storage space. The rotation limiting rib restricts the rotation angle of the connecting pin on the connector, allowing it to rotate only 90° relative to the connector. This limitation ensures good stability of the crossbeam during operation.

[0011] Preferably, the column includes a top connecting block, an upper support rod, a middle connecting block, and a lower support rod. The crossbeam connecting groove is disposed on the top connecting block, the top connecting block is disposed on the top of the upper support rod and is inserted and fixed thereto, the middle connecting block is disposed on the top of the lower support rod and is inserted and fixed thereto, the top of the lower support rod is mounted on the bottom of the upper support rod through the middle connecting block and is detachably connected to it, and the bottom of the lower support rod is placed in the column connecting hole and is slidably connected to it vertically. The segmented design of the top connecting block, upper support rod, middle connecting block, and lower support rod facilitates the storage and organization of the column, saving storage space.

[0012] Preferably, the bottom of the middle connecting block and the top of the lower support rod are inserted and fixed. The bottom of the upper support rod is provided with a connecting block slot that matches the top of the middle connecting block. The side wall of the connecting block slot is provided with an axial movable channel and a horizontal movable channel. One end of the axial movable channel is located at the opening of the connecting block slot. The other end of the axial movable channel is connected to one end of the horizontal movable channel. The other end of the horizontal movable channel is provided with a limit pin groove. The limit pin groove and the axial movable channel are respectively located on opposite side walls of the horizontal movable channel. A limit pin is fixed on the side wall of the middle connecting block. The limit pin is placed on the top of the middle connecting block. The limit pin is slidably connected with the axial movable channel and the horizontal movable channel. The limit pin is engaged with the limit pin groove. When installing the upper and lower support rods, first insert and fix the bottom of the middle connecting block to the top of the lower support rod. Then, align the top of the middle connecting block with the connecting block slot at the bottom of the upper support rod and insert it. During the insertion process, rotate the upper support rod to allow the limiting pin on the middle connecting block to slide into the limiting pin slot through the axial and horizontal movable channels in sequence. This completes the installation and fixation between the upper and lower support rods. The structure is simple, the operation is convenient, the fixing effect is good, and it is easy to install and disassemble.

[0013] Preferably, the upright also includes a bottom connecting column. The bottom of the lower support rod has a connecting column slot, and the top of the bottom connecting column has a step that matches the connecting column slot. The lower support rod is inserted into the bottom connecting column through the connection of the connecting column slot and the step. The bottom connecting column is placed in the connecting hole of the upright and slides vertically with it. During installation, the clamps can be fixed to the bed edges on both sides first. Then, the bottom connecting column is inserted into the connecting hole of the upright and adjusted to the required height. Next, the upright and the crossbeam are assembled and fixed according to the distance between the bottom connecting columns on both sides, so that the distance between the two uprights matches the distance between the bottom connecting columns on both sides. Finally, the gantry structure composed of the upright and the crossbeam is inserted into the bottom connecting column through the connection of the connecting column slot and the step, greatly improving the convenience of installation.

[0014] The advantages of this utility model are: simple structure, convenient adjustment, low operation difficulty, and easy to adjust the height of the crossbeam or the distance between the two columns individually; improved assembly convenience; improved fixing effect of the crossbeam in the crossbeam connecting groove; easy to store and organize the crossbeam and columns, saving storage space; simple structure, convenient operation, good fixing effect, and easy to install and disassemble. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 yes Figure 1 The front view showing the connection between the beam and the column; Figure 3 yes Figure 2 Sectional view at point AA; Figure 4 yes Figure 3 Enlarged view of point B in the middle; Figure 5 This is a schematic diagram of the structure connecting the upper support rod, the middle connecting block, and the lower support rod; Figure 6 This is a structural diagram of another possible design for the crossbeam.

[0016] In the diagram: 1. Crossbeam, 2. Column, 3. Crossbeam connecting groove, 4. Clamp, 5. Column connecting hole, 6. Screw hole one, 7. Tightening screw one, 8. Pressure plate, 9. Knob, 10. Limiting stop, 11. Beam segment one, 12. Beam segment connecting seat, 13. Beam segment two, 14. Beam segment connecting pin, 15. Rotation limiting rib, 16. Top connecting block, 17. Upper support rod, 18. Middle connecting block, 19. Lower support rod, 20. Connecting block slot, 21. Axial movement channel, 22. Horizontal movement channel, 23. Limiting pin slot, 24. Limiting pin, 25. Bottom connecting column, 56. Screw hole two, 57. Tightening screw two. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1 In the embodiments described above, a main frame support structure for a balance hook device includes: Crossbeam 1; The column 2 is set on both sides of the crossbeam 1. The top of the column 2 is provided with a crossbeam connecting groove 3 that matches the crossbeam 1. The top of the column 2 is installed on the crossbeam 1 through the crossbeam connecting groove 3 and is slidably connected to it on the left and right. Locking device 1 is installed at the connection between column 2 and beam 1; A clamp 4 is located at the bottom of the column 2. The clamp 4 has a column connection hole 5 that matches the column 2. The bottom of the column 2 is placed inside the column connection hole 5 and slidably connected to it. A locking device 2 corresponding to the column 2 is installed at the column connection hole 5. A screw hole 2 56 is provided on the side wall of the column connection hole 5. The locking device 2 includes a tightening screw 2 57 threadedly connected to the screw hole 2 56. A movable handle 1 is also installed at the tail end of the tightening screw 2 57. The user can tighten the screw hole 2 56 to press it against the bottom of the lower support rod 19, thus achieving relative fixation between the column 2 and the clamp 4.

[0019] More specifically, beam 1 can be a square bar.

[0020] like Figure 2 , Figure 3 and Figure 4 As shown, the crossbeam connecting groove 3 includes a connecting groove opening, a connecting groove bottom surface, a connecting groove side wall one, and a connecting groove side wall two. A screw hole 6 is provided on the connecting groove side wall one. The locking device one includes a tightening screw 7 that is threadedly connected to the screw hole 6. One end of the tightening screw 7 is placed inside the crossbeam connecting groove 3 and a pressure plate 8 is fixed thereon. The other end of the tightening screw 7 is placed outside the crossbeam connecting groove 3 and a knob 9 is fixed thereon.

[0021] A limiting stop 10 facing the first side wall of the connecting groove is fixed on the second side wall of the connecting groove. The limiting stop 10 is located at the opening of the connecting groove. The distance between the side of the limiting stop 10 facing the bottom of the connecting groove and the bottom of the connecting groove is adapted to the longitudinal section height of the crossbeam 1. The sum of the distance between the side of the limiting stop 10 close to the first side wall of the connecting groove and the longitudinal section width of the crossbeam 1 is adapted to the distance between the first side wall of the connecting groove and the second side wall of the connecting groove.

[0022] like Figure 6 As shown, the crossbeam 1 includes beam segment 11, beam segment connecting seat 12, and beam segment 2 13. Beam segment connecting seat 12 is positioned between beam segment 11 and beam segment 2 13. Both ends of beam segment connecting seat 12 are provided with beam segment connecting pins 14, which are hinged to each other. One end of beam segment connecting pin 14 is inserted and fixed to the end of beam segment 11, and the other end of beam segment connecting pin 14 is inserted and fixed to the end of beam segment 2 13. A rotation limiting rib 15 is also fixed to the beam segment connecting seat 12, positioned on the side of the beam segment connecting pin 14. The ends of beam segment 11 and beam segment 2 13 are provided with insertion slots that match the beam segment connecting pins 14. The insertion points of beam segment 11 and beam segment 2 13 with the two beam segment connecting pins 14 can be permanently fixed by welding, or a detachable insertion fixation can be maintained. The relative rotation design of beam segment 11 and beam segment 2 13 facilitates the storage and organization of crossbeam 1, saving storage space.

[0023] like Figure 5 As shown, the column 2 includes a top connecting block 16, an upper support rod 17, a middle connecting block 18, and a lower support rod 19. A crossbeam connecting groove 3 is disposed on the top connecting block 16. The top connecting block 16 is located on top of the upper support rod 17 and is inserted and fixed thereto. The middle connecting block 18 is located on top of the lower support rod 19 and is inserted and fixed thereto. The top of the lower support rod 19 is installed at the bottom of the upper support rod 17 via the middle connecting block 18 and is detachably connected to it. The bottom of the lower support rod 19 is placed in the column connecting hole 5 and is slidably connected to it. The top of the upper support rod 19 has a matching socket that matches the bottom of the top connecting block 16. The socket between the top connecting block 16 and the upper support rod 19 can be permanently fixed by welding or can remain detachably fixed. The top of the lower support rod 19 has a matching socket that matches the bottom of the middle connecting block 18. The socket between the middle connecting block 18 and the lower support rod 19 can be permanently fixed by welding or can remain detachably fixed. The segmented design of the top connecting block 16, upper support rod 17, middle connecting block 18 and lower support rod 19 makes it easy to store and organize the column 2, saving storage space.

[0024] The bottom of the middle connecting block 18 and the top of the lower support rod 19 are inserted and fixed. The bottom of the upper support rod 17 is provided with a connecting block slot 20 that matches the top of the middle connecting block 18. The side wall of the connecting block slot 20 is provided with an axial movable channel 21 and a horizontal movable channel 22. One end of the axial movable channel 21 is located at the opening of the connecting block slot 20. The other end of the axial movable channel 21 is connected to one end of the horizontal movable channel 22. The other end of the horizontal movable channel 22 is provided with a limit pin groove 23. The limit pin groove 23 and the axial movable channel 21 are respectively located on the opposite side walls of the horizontal movable channel 22. A limit pin 24 is fixed on the side wall of the middle connecting block 18. The limit pin 24 is placed on the top of the middle connecting block 18. The limit pin 24 is slidably connected with the axial movable channel 21 and the horizontal movable channel 22. The limit pin 24 is engaged with the limit pin groove 23. When installing the upper support rod 17 and the lower support rod 19, first insert and fix the bottom of the middle connecting block 18 to the top of the lower support rod 19. Then, align the top of the middle connecting block 18 with the connecting block slot 20 at the bottom of the upper support rod 17 and insert it. During the insertion process, rotate the upper support rod 17 to make the limiting pin 24 on the middle connecting block 18 slide into the limiting pin slot 23 in sequence through the axial movable channel 21 and the horizontal movable channel 22.

[0025] like Figure 1 and Figure 3 As shown, the column 2 also includes a bottom connecting column 25. The bottom of the lower support rod 19 is provided with a connecting column slot, and the top of the bottom connecting column 25 is provided with a step that matches the connecting column slot. The lower support rod 19 is inserted into the bottom connecting column 25 through the cooperation of the connecting column slot and the step. The bottom connecting column 25 is placed in the column connecting hole 5 and is slidably connected to it.

[0026] During installation, first fix the clamp 4 to the bed edges on both sides, then insert the bottom connecting post 25 into the column connecting hole 5 and adjust it to the required height. Then, use the locking device 2 to fix the bottom connecting post 25. After that, assemble and fix the column 2 and the crossbeam 1 according to the distance between the bottom connecting posts 25 on both sides, so that the distance between the two columns 2 matches the distance between the bottom connecting posts 25 on both sides. When assembling the crossbeam 1 and the column 2, it can be inserted into the crossbeam connecting groove 3 from the opening of the connecting groove, or it can be inserted into the crossbeam connecting groove 3 from the side. After the crossbeam 1 is installed into the crossbeam connecting groove 3 on the column 2, adjust the distance between the two columns 2 according to the distance between the bottom connecting posts 25 on both sides, and press the crossbeam 1 onto the side wall of the connecting groove 2 by tightening the screw 7. Then, combine the limiting stop 10 at the top of the side wall of the connecting groove 2 to limit and block the crossbeam 1, thereby fixing the crossbeam 1 in the crossbeam connecting groove 3. Finally, by using the joint of the column slot and the step, the gantry structure composed of column 2 and beam 1 is inserted into the bottom column 25.

[0027] When adjusting the distance between the two columns 2, the locking device 2 can be used to fix the columns 2 and the clamp 4 relatively to prevent the columns 2 from sliding up and down, so that the height of the crossbeam 1 can always remain constant. Then, the columns 2 can slide left and right on the crossbeam 1 through the crossbeam connecting groove 3 on them, so as to achieve individual adjustment of the distance between the two columns 2. After the adjustment is completed, the locking device 1 can be used to fix the crossbeam 1 and the columns 2 relatively again. When adjusting the height of the crossbeam 1, the locking device 1 can be used to fix the crossbeam 1 and the columns 2 relatively to prevent the columns 2 from sliding left and right on the crossbeam 1, so that the distance between the two columns 2 can always remain constant. Then, the columns 2 can slide up and down in the column connecting hole 5 on the clamp 4, so as to achieve individual adjustment of the height of the crossbeam 1. After the adjustment is completed, the locking device 2 can be used to fix the columns 2 and the clamp 4 relatively again.

Claims

1. A main frame support structure for a balance hook device, characterized in that, include: Crossbeam (1); The column (2) is set on both sides of the crossbeam (1). The top of the column (2) is provided with a crossbeam connecting groove (3) that matches the crossbeam (1). The top of the column (2) is installed on the crossbeam (1) through the crossbeam connecting groove (3) and is slidably connected to it to the left and right. Locking device one is installed at the connection between the column (2) and the crossbeam (1); A clamp (4) is provided at the bottom of the column (2). The clamp (4) is provided with a column connection hole (5) that matches the column (2). The bottom of the column (2) is placed in the column connection hole (5) and is slidably connected to it. A locking device II corresponding to the column (2) is installed at the column connection hole (5).

2. The main frame support structure of the balance hook device according to claim 1, characterized in that, The crossbeam connecting groove (3) includes a connecting groove opening, a connecting groove bottom surface, a connecting groove side wall one and a connecting groove side wall two. A screw hole one (6) is provided on the connecting groove side wall one. The locking device one includes a tightening screw one (7) that is threadedly connected to the screw hole one (6). One end of the tightening screw one (7) is placed inside the crossbeam connecting groove (3) and a pressure plate (8) is fixed thereon. The other end of the tightening screw one (7) is placed outside the crossbeam connecting groove (3) and a knob (9) is fixed thereon.

3. The main frame support structure of the balance hook device according to claim 2, characterized in that, A limiting stop (10) facing the first sidewall of the connecting groove is fixed on the second sidewall of the connecting groove. The limiting stop (10) is located at the opening of the connecting groove. The distance between the side of the limiting stop (10) facing the bottom surface of the connecting groove and the bottom surface of the connecting groove is adapted to the longitudinal section height of the crossbeam (1). The sum of the distance between the side of the limiting stop (10) close to the first sidewall of the connecting groove and the longitudinal section width of the crossbeam (1) is adapted to the distance between the first sidewall of the connecting groove and the second sidewall of the connecting groove.

4. The main frame support structure of the balance hook device according to claim 1, characterized in that, The crossbeam (1) includes a beam segment one (11), a beam segment connecting seat (12), and a beam segment two (13). The beam segment connecting seat (12) is placed between the beam segment one (11) and the beam segment two (13). Both ends of the beam segment connecting seat (12) are provided with beam segment connecting pins (14). The beam segment connecting pins (14) and the beam segment connecting seat (12) are hinged together. The end of one beam segment connecting pin (14) is inserted and fixed to the end of the beam segment one (11), and the end of the other beam segment connecting pin (14) is inserted and fixed to the end of the beam segment two (13). The beam segment connecting seat (12) is also fixed with a rotation limiting rib (15), which is placed on the side of the beam segment connecting pin (14).

5. The main frame support structure of the balance hook device according to claim 1, characterized in that, The column (2) includes a top connecting block (16), an upper support rod (17), a middle connecting block (18), and a lower support rod (19). The crossbeam connecting groove (3) is set on the top connecting block (16). The top connecting block (16) is set on the top of the upper support rod (17) and is inserted and fixed thereto. The middle connecting block (18) is set on the top of the lower support rod (19) and is inserted and fixed thereto. The top of the lower support rod (19) is installed on the bottom of the upper support rod (17) through the middle connecting block (18) and is detachably connected thereto. The bottom of the lower support rod (19) is placed in the column connecting hole (5) and is slidably connected thereto.

6. The main frame support structure of the balance hook device according to claim 5, characterized in that, The bottom of the middle connecting block (18) and the top of the lower support rod (19) are inserted and fixed. The bottom of the upper support rod (17) is provided with a connecting block slot (20) that matches the top of the middle connecting block (18). An axial movable channel (21) and a horizontal movable channel (22) are provided on the side wall of the connecting block slot (20). One end of the axial movable channel (21) is located at the opening of the connecting block slot (20), and the other end of the axial movable channel (21) is connected to one end of the horizontal movable channel (22). A limit pin groove (23) is provided at the other end of the horizontal movable channel (22). The limit pin groove (23) and the axial movable channel (21) are respectively located on the opposite side walls of the horizontal movable channel (22). A limit pin (24) is fixed on the side wall of the middle connecting block (18). The limit pin (24) is placed on the top of the middle connecting block (18). The limit pin (24) is slidably connected to the axial movable channel (21) and the horizontal movable channel (22). The limit pin (24) is engaged with the limit pin groove (23).

7. The main frame support structure of the balance hook device according to claim 5, characterized in that, The column (2) also includes a bottom connecting column (25). The bottom of the lower support rod (19) is provided with a connecting column slot. The top of the bottom connecting column (25) is provided with a step that matches the connecting column slot. The lower support rod (19) is inserted into the bottom connecting column (25) through the cooperation of the connecting column slot and the step. The bottom connecting column (25) is placed in the column connecting hole (5) and is slidably connected to it.

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