Horizontal knee joint rehabilitation training device
Through a horizontal knee rehabilitation training device that independently adjusts the calf and thigh, the problem of excessive movement in the existing device is solved, and the refined training needs for patients with severe injuries or early recovery are achieved, and the rehabilitation needs at different stages are met.
Patent Information
- Application Number
- CN202422192813.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-06
- Publication Date
- 2025-09-02
- Estimated Expiration
- 2034-09-06
AI Technical Summary
The existing horizontal knee rehabilitation training device. During knee rehabilitation training, synchronous movement of the thigh and calf may lead to excessive movement amplitude, which cannot meet the training needs of patients with severe injuries or early recovery, and lacks fine adjustment capabilities.
A horizontal knee rehabilitation training device is designed, and the calf and thigh are fixed by independent first support rods and second support rods, allowing the calf to lift and lower independently, while the thigh is maintained stable, and the angle is adjusted through the limit structure to control the movement amplitude.
It effectively avoids excessive leg movement, meets the training needs of patients with severe injuries or early recovery, and provides fine training intensity and method adjustment ability.
Smart Images
Figure CN223287360U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of medical equipment, and in particular relates to a horizontal knee joint rehabilitation training device. Background Art
[0002] With the development of medical technology and the improvement of people's health awareness, rehabilitation equipment plays an increasingly important role in assisting patients to recover their functions. Especially for patients after knee surgery, effective rehabilitation training can help them recover joint function faster and reduce the occurrence of complications. Most of the knee rehabilitation training devices on the market are vertical designs, requiring patients to stand when using them. This makes it difficult for some patients who have just undergone surgery or are in the early stages of injury to use them. As an improved device, the horizontal knee rehabilitation training device can perform knee rehabilitation training while the patient is lying flat, thereby reducing the patient's physical burden during training.
[0003] While horizontal knee rehabilitation training devices offer some improvements over vertical designs, they still have some shortcomings in practical application. Specifically, existing horizontal devices often synchronize the thigh and calf movements during knee rehabilitation training. This can result in excessive range of motion and fail to meet the training needs of patients with severe injuries or those in the early stages of rehabilitation. Furthermore, existing devices often lack fine-tuning capabilities, making it difficult for patients to adjust the intensity and method of training based on their recovery progress. Utility Model Content
[0004] The purpose of the utility model is to address the above-mentioned problems in the prior art and to provide a horizontal knee joint rehabilitation training device that can independently adjust the positions of the thigh and calf and has a simple structure.
[0005] The purpose of the utility model can be achieved through the following technical solutions, a horizontal knee joint rehabilitation training device, comprising:
[0006] scaffolding;
[0007] a first adjustment assembly, the first adjustment assembly comprising a first support rod escalably mounted on the base frame, the first support rod being provided with a first fixing structure for fixing the calf;
[0008] The second adjustment component includes a second support rod arranged on the base frame, and the second support rod is provided with a second fixing structure for fixing the thigh, wherein there is a gap between the second support rod and the first support rod, when the first support rod is raised and lowered relative to the base frame, the first fixing structure moves synchronously toward or away from the base frame, and the second fixing structure remains stationary relative to the base frame.
[0009] In the above-mentioned horizontal knee joint rehabilitation training device, the first support rod and the second support rod are on the same straight line near the end of the base frame, wherein the first support rod is arranged vertically, the second support rod is arranged inclined, and an angle is formed between the first support rod and the second support rod.
[0010] In the above-mentioned horizontal knee joint rehabilitation training device, the second support rod is rotatably connected to the base frame, and the base frame is provided with a limiting structure that forms a snap fit with the second support rod and can limit the movement of the second support rod, and the limiting structure has multiple snap positions. When the second support rod moves between the multiple snap positions, the size of the angle can be adjusted.
[0011] In the above-mentioned horizontal knee joint rehabilitation training device, the limiting structure includes a support member and a limiting member. The support member extends along the rotation direction of the second support rod, and is provided with a plurality of limiting holes corresponding to the clamping positions along the length direction, and a connecting hole is provided on the second support rod. When the limiting member is sequentially inserted into the limiting hole and the connecting hole, the limiting structure can limit the movement of the second support rod, and the limiting member can adjust the size of the angle by being inserted into different limiting holes.
[0012] In the above-mentioned horizontal knee joint rehabilitation training device, the support member includes a first limiting surface and a second limiting surface arranged relatively to each other, and there is a gap between the first limiting surface and the second limiting surface for the second support rod to pass through, and the gap is adapted to the width of the second support rod, and the first limiting surface and the second limiting surface can limit the movement of the second support rod toward the arrangement direction of the first limiting surface and the second limiting surface.
[0013] In the above-mentioned horizontal knee joint rehabilitation training device, the plurality of limiting holes are respectively arranged on the first limiting surface and the second limiting surface, and are arranged in their respective length directions. The limiting holes on the first limiting surface correspond one to one with the limiting holes on the second limiting surface and are coaxial, and there are two groups of connecting holes, which are respectively located on both sides of the second support rod and are coaxially arranged.
[0014] In the above-mentioned lying knee joint rehabilitation training device, the first fixing structure includes a first placing plate and a first strap, the first placing plate is rotatably arranged on the first support rod, and the first strap is detachably arranged on the first placing plate, for fixing the calf on the first placing plate. When the calf is on the first placing plate and the first support rod is raised and lowered, the first placing plate can rotate relative to the first support rod under the action of the gravity of the calf.
[0015] In the above-mentioned horizontal knee joint rehabilitation training device, the first placement plate includes a first supporting part and a first rotating part, the first supporting part is provided with a first groove extending along the length direction of the first placement plate, the first rotating part is rotatably connected with the first support rod through a first rotating shaft, and the first support rod is provided with a first movable groove for the first rotating part to rotate.
[0016] In the above-mentioned lying knee joint rehabilitation training device, the second fixing structure includes a second placement plate and a second strap, the second placement plate is rotatably arranged on the second support rod, and the second strap is detachably arranged on the second placement plate for fixing the thigh on the second placement plate.
[0017] In the above-mentioned horizontal knee joint rehabilitation training device, the second placement plate includes a second supporting part and a second rotating part, the second supporting part is provided with a second groove extending along the length direction of the second placement plate, the second rotating part is rotatably connected with the second support rod through a second rotating shaft, the second rotating shaft is provided with a locking nut, and the second support rod is provided with a second movable groove for rotation of the second rotating part.
[0018] Compared with the prior art, the present invention offers the following advantages: by providing independent first and second support rods, with the first fixing structure for securing the calf and the second fixing structure for securing the thigh located on the first and second support rods, respectively, the calf can be raised and lowered as needed while the thigh remains stable. This effectively prevents excessive leg movement while providing knee rehabilitation training, thus meeting the training needs of patients with severe injuries or those in the early stages of rehabilitation. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is a structural schematic diagram of a horizontal knee joint rehabilitation training device according to an embodiment of the present utility model.
[0020] Figure 2 This is an exploded view of a horizontal knee joint rehabilitation training device according to an embodiment of the present utility model.
[0021] Figure 3 for Figure 1 Schematic diagram of the structure from another perspective.
[0022] In all the drawings, the same reference numerals denote the same technical features, specifically: 100, base frame; 110, base; 120, vertical rod; 121, adjustment hole; 130, horizontal rod; 131, connecting sleeve; 132, fixing hole; 200, first adjustment assembly; 210, first support rod; 211, first movable groove; 220, first fixing structure; 221, first placement plate; 222, first strap; 223, first lifting portion; 224, first rotating portion; 225, first groove; 226, first rotating shaft; 3 00. Second adjustment component; 310. Second support rod; 311. Connecting hole; 312. Second movable groove; 320. Second fixing structure; 321. Second placement plate; 322. Second strap; 323. Second lifting part; 324. Second rotating part; 325. Second groove; 326. Second rotating shaft; 400. Limiting structure; 410. Support member; 411. First limiting surface; 412. Second limiting surface; 420. Limiting member; 430. Limiting hole; 500. Display screen; 600. Casters; 700. Handle. DETAILED DESCRIPTION
[0023] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention, but the present invention is not limited to these embodiments.
[0024] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.
[0025] like Figures 1 to 3 As shown, a recumbent knee joint rehabilitation training device includes a base frame 100, a first adjustment component 200, a second adjustment component 300, a limiting structure 400, a display screen 500, casters 600 and a handle 700.
[0026] like Figures 1 to 3 As shown, a recumbent knee joint rehabilitation training device comprises:
[0027] Base frame 100;
[0028] The first adjustment assembly 200 includes a first support rod 210 movably mounted on the base frame 100 , and a first fixing structure 220 for fixing the calf is provided on the first support rod 210 ;
[0029] The second adjustment assembly 300 includes a second support rod 310 disposed on the base frame 100. The second support rod 310 is provided with a second fixing structure 320 for fixing the thigh. A gap is provided between the second support rod 310 and the first support rod 210. When the first support rod 210 is raised or lowered relative to the base frame 100, the first fixing structure 220 simultaneously moves toward or away from the base frame 100, while the second fixing structure 320 remains stationary relative to the base frame 100. By providing independent first and second support rods 210 and 310, and by having the first fixing structure 220 for fixing the calf and the second fixing structure 320 for fixing the thigh respectively disposed on the first and second support rods 210 and 310, the calf portion can be raised or lowered as needed, while the thigh portion remains stable. While achieving knee joint rehabilitation training, it effectively avoids excessive leg movement, thereby meeting the training needs of patients with severe injuries or those in the early stages of rehabilitation.
[0030] Specifically, if Figures 1 to 3 As shown, in this embodiment, the base frame 100 includes a base 110, a vertical rod 120 vertically arranged on the base 110, and a horizontal rod 130 arranged horizontally and movably connected to the vertical rod 120. The base 110 is provided with a plurality of rotatable casters 600. Preferably, there are four casters 600, respectively provided at the four corners of the base 110, so that the operator can smoothly move the device to the work site as needed, effectively improving the flexibility of the device.
[0031] In this embodiment, the base 110 is provided with a U-shaped groove, which passes through the base 110 and extends along the length of the base 110, and is shorter than the length of the base 110. This design reduces the weight of the device while ensuring the supporting force of the device, thereby improving the convenience of the device.
[0032] In this embodiment, the vertical rod 120 extends vertically in a direction away from the base 110, and a display screen 500 is provided at the extended end. The display screen 500 has a built-in control system for realizing intelligent control of the device.
[0033] Preferably, in this embodiment, a handle 700 is further provided at one end of the vertical rod 120 away from the base 110. The handle 700 is U-shaped and has two groups arranged opposite to each other, so that the operator can easily apply push or pull force to the device, further improving the convenience of moving the device.
[0034] In this embodiment, the vertical rod 120 is provided with a plurality of adjustment holes 121 along the length direction, and the cross rod 130 is provided with a connecting sleeve 131 near one end of the vertical rod 120. The connecting sleeve 131 is movably mounted on the vertical rod 120. When the connecting sleeve 131 moves between the plurality of adjustment holes 121, the height of the cross rod 130 can be adjusted, thereby meeting the requirements of adjusting the height of the first adjustment component 200 and the second adjustment component 300.
[0035] In this embodiment, the connecting sleeve 131 is U-shaped and forms a three-sided fitting connection with the vertical rod 120, and a fixing hole 132 is provided on the connecting sleeve 131. When the connecting sleeve 131 moves to a coaxial position between the fixing hole 132 and the adjustment hole 121, a fastener (not shown in the figure) is sequentially inserted into the fixing hole 132 and the adjustment hole 121 to achieve a stable connection between the cross bar 130 and the vertical rod 120, thereby effectively ensuring the stability of the cross bar 130 after adjustment, and thereby ensuring the stability of the device during operation.
[0036] In order to achieve knee joint rehabilitation training for patients, in this embodiment, a first adjustment component 200 is provided for driving the calf to swing up and down, and a second adjustment component 300 is provided for fixing the thigh. Through the cooperation of the first adjustment component 200 and the second adjustment component 300, the knee joint can be rehabilitated under the movement of the calf, and by making the first adjustment component 200 and the second adjustment component 300 independent of each other, the synchronous movement of the thigh when the calf is raised and lowered is effectively avoided.
[0037] In this embodiment, the first adjustment component 200 includes a first support rod 210 that can be raised and lowered on the cross bar 130. The first support rod 210 is provided with a first fixing structure 220 for fixing the calf at one end away from the cross bar 130. While supporting the calf, the patient's calf can swing up and down through the lifting and lowering movement of the first support rod 210.
[0038] In this embodiment, the second adjustment component 300 includes a second support rod 310 arranged on the cross bar 130, and the second support rod 310 is provided with a second fixing structure 320 for fixing the thigh at one end away from the cross bar 130. There is a gap between the second support rod 310 and the first support rod 210, which effectively ensures the independence between the first support rod 210 and the second support rod 310, so that when the patient's calf swings up and down, the thigh is fixed on the second support rod 310, effectively controlling the overall movement range of the leg, avoiding secondary injury to the patient due to excessive movement range, thereby meeting the training needs of patients who are seriously injured or in the early stages of recovery.
[0039] In this embodiment, the first and second support rods 210 and 310 are aligned at their ends near the base frame 100. The first support rod 210 is vertically arranged, while the second support rod 310 is tilted, with an angle formed between the first and second support rods 210 and 310. This design allows the thigh to be tilted and the calf to be horizontal. This not only ensures ample room for the first support rod 210 to move, allowing the calf to swing up and down, but also helps simulate the natural knee flexion of the human body, improving patient comfort.
[0040] To accommodate the different stages of knee rehabilitation training, in this embodiment, the second support rod 310 is rotatably connected to the crossbar 130. A retaining structure 400 is provided on the crossbar 130, which engages with the second support rod 310 and limits its movement. The retaining structure 400 has multiple engaging positions, allowing the angle between the positions to be adjusted. Adjusting this angle allows the range of motion of the first support rod 210 to be adjusted, thereby varying the range of motion of the lower leg to accommodate the different stages of rehabilitation training.
[0041] In this embodiment, the limiting structure 400 includes a support member 410 and a limiting member 420. The support member 410 is disposed at the end of the horizontal rod 130 away from the vertical rod 120, extending along the rotation direction of the second support rod 310, and is provided with a plurality of limiting holes 430 corresponding to the engaging positions along the length direction. The second support rod 310 is provided with a connecting hole 311. When the limiting member 420 is sequentially engaged with the limiting holes 430 and the connecting hole 311, the limiting structure 400 can restrict the movement of the second support rod 310. The limiting member 420 can adjust the size of the included angle by engaging with different limiting holes 430. The cooperation of the limiting holes 430, the connecting hole 311, and the limiting member 420 realizes a stable and simple adjustment mechanism, allowing the operator to quickly adjust and fix the desired angle as needed.
[0042] In this embodiment, the support member 410 includes a first limiting surface 411 and a second limiting surface 412 arranged opposite to each other. The first limiting surface 411 and the second limiting surface 412 are arc-shaped, with a gap therebetween for the second support rod 310 to pass through. The gap is adapted to the width of the second support rod 310, and the first limiting surface 411 and the second limiting surface 412 are capable of limiting the movement of the second support rod 310 in the direction of the arrangement of the first limiting surface 411 and the second limiting surface 412. This not only effectively prevents the second support rod 310 from shifting left or right during the angle adjustment process, but also ensures that the contact area between the limiting structure 400 and the second support rod 310 is expanded, thereby ensuring the stability of the second support rod 310 when it is fixed.
[0043] In this embodiment, the plurality of limiting holes 430 are respectively provided on the first limiting surface 411 and the second limiting surface 412 and arranged along their respective lengths. The limiting holes 430 on the first limiting surface 411 correspond one-to-one with the limiting holes 430 on the second limiting surface 412 and are coaxial. Furthermore, the connecting holes 311 are provided in two groups, one on each side of the second support rod 310 and arranged coaxially. This design allows the limiting member 420 to penetrate the second support rod 310 and engage with each of the two groups of limiting holes 430, ensuring uniform force on both sides of the support member 410, thereby ensuring the stability of the second support rod 310 and the service life of the entire device.
[0044] In this embodiment, the first support rod 210 includes a fixed rod and a lifting rod. The fixed rod is L-shaped and is provided with a driving structure (not shown in the figure). The lifting rod is movably mounted in the fixed rod and connected to the driving structure. Driven by the driving structure, it performs lifting and lowering movements along the length direction of the fixed rod.
[0045] Preferably, in this embodiment, the driving structure is a driving motor or a driving cylinder or a hydraulic cylinder.
[0046] In this embodiment, the first fixing structure 220 includes a first placement plate 221 and a first strap 222. The first placement plate 221 is rotatably mounted on the lifting rod of the first support rod 210, and the first strap 222 is detachably mounted on the first placement plate 221 to secure the calf to the first placement plate 221. When the calf is on the first placement plate 221 and the first support rod 210 is raised or lowered, the first placement plate 221 can rotate relative to the first support rod 210 under the action of the calf's gravity. The rotatable design of the first placement plate 221 ensures that the calf remains in contact with the first placement plate 221 during the upward and downward swinging process, effectively preventing injury to the calf during movement. The design of the first strap 222 ensures the stability of the fixation between the calf and the first placement plate 221, while also facilitating donning and doffing for the patient.
[0047] In this embodiment, the first placement plate 221 includes a first supporting portion 223 and a first rotating portion 224. The first supporting portion 223 is provided with a first groove 225 extending along the length of the first placement plate 221. The first rotating portion 224 is rotatably connected to the first support rod 210 via a first rotating shaft 226. The first support rod 210 is provided with a first movable groove 211 for the rotation of the first rotating portion 224. The design of the first groove 225 allows the calf to be partially covered therein, which not only improves the comfort of the calf during placement but also ensures a tight fit between the two.
[0048] In this embodiment, the second support rod 310 is a hollow structure, one end of which is rotatably connected to the cross bar 130 through a rotating shaft, and the other end passes through the support member 410 and is rotatably connected to the second fixed structure 320 to achieve support and fixation of the thigh.
[0049] In this embodiment, the second fixing structure 320 includes a second placement plate 321 and a second strap 322. The second placement plate 321 is rotatably mounted on the end of the second support rod 310 away from the crossbar 130. The second strap 322 is detachably mounted on the second placement plate 321 and is used to secure the thigh to the second placement plate 321. The rotatable design of the second placement plate 321 allows the operator to adjust the angle of the thigh as needed, effectively improving the precise control and adjustment of the device during training. The design of the second strap 322 ensures the stability of the fixation between the thigh and the second placement plate 321, while also making it easier for the patient to put on and take off the device.
[0050] In this embodiment, the second placement plate 321 includes a second supporting portion 323 and a second rotating portion 324. The second supporting portion 323 is provided with a second groove 325 extending along the length of the second placement plate 321. The second rotating portion 324 is rotatably connected to the second support rod 310 via a second rotating shaft 326. The second support rod 310 is provided with a second movable groove 312 for the rotation of the second rotating portion 324. The design of the second groove 325 allows the thigh to be partially enclosed therein, which not only improves the comfort of the thigh during placement but also ensures a tight fit between the thigh and the support rod.
[0051] It is worth noting that, in order to ensure the stability of the second placement plate 321 after the angle is adjusted, in this embodiment, a locking nut (not shown in the figure) is further provided on the second rotating shaft 326.
[0052] It should be noted that, in the present utility model, descriptions such as "first", "second", "one", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly defined. The terms "connected", "fixed", etc. should be understood in a broad sense. For example, "fixed" can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to the specific circumstances.
[0053] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in this field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this utility model.
[0054] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Persons skilled in the art may make various modifications, additions, or substitutions to the described specific embodiments without departing from the spirit of the present invention or exceeding the scope defined by the appended claims.
Claims
1. A recumbent knee joint rehabilitation training device, characterized in that: include: scaffolding; a first adjustment assembly, the first adjustment assembly comprising a first support rod escalably mounted on the base frame, the first support rod being provided with a first fixing structure for fixing the calf; The second adjustment component includes a second support rod arranged on the base frame, and the second support rod is provided with a second fixing structure for fixing the thigh, wherein there is a gap between the second support rod and the first support rod, when the first support rod is raised and lowered relative to the base frame, the first fixing structure moves synchronously toward or away from the base frame, and the second fixing structure remains stationary relative to the base frame.
2. A recumbent knee joint rehabilitation training device according to claim 1, characterized in that: The first support rod and the second support rod are located on the same straight line at their ends close to the base frame, wherein the first support rod is arranged vertically, the second support rod is arranged obliquely, and an angle is formed between the first support rod and the second support rod.
3. A recumbent knee joint rehabilitation training device according to claim 2, characterized in that: The second support rod is rotatably connected to the base frame, and the base frame is provided with a limiting structure that forms a snap fit with the second support rod and can limit the movement of the second support rod, and the limiting structure has multiple snap positions. When the second support rod moves between the multiple snap positions, the size of the angle can be adjusted.
4. A recumbent knee joint rehabilitation training device according to claim 3, characterized in that: The limiting structure includes a support member and a limiting member. The support member extends along the rotation direction of the second support rod and is provided with a plurality of limiting holes corresponding to the clamping positions along the length direction, and a connecting hole is provided on the second support rod. When the limiting member is sequentially inserted into the limiting hole and the connecting hole, the limiting structure can limit the movement of the second support rod, and the limiting member can adjust the size of the angle by being inserted into different limiting holes.
5. A recumbent knee joint rehabilitation training device according to claim 4, characterized in that: The support member includes a first limiting surface and a second limiting surface arranged relatively to each other, and there is a gap between the first limiting surface and the second limiting surface for the second support rod to pass through, the gap is adapted to the width of the second support rod, and the first limiting surface and the second limiting surface can limit the movement of the second support rod toward the arrangement direction of the first limiting surface and the second limiting surface.
6. A recumbent knee joint rehabilitation training device according to claim 5, characterized in that: The plurality of limiting holes are respectively arranged on the first limiting surface and the second limiting surface, and are arranged along their respective length directions. The limiting holes on the first limiting surface correspond one to one with the limiting holes on the second limiting surface and are coaxial, and there are two groups of connecting holes, which are respectively located on both sides of the second support rod and are coaxially arranged.
7. The recumbent knee joint rehabilitation training device according to claim 1, characterized in that: The first fixing structure includes a first placing plate and a first strap. The first placing plate is rotatably arranged on the first support rod. The first strap is detachably arranged on the first placing plate and is used to fix the calf on the first placing plate. When the calf is on the first placing plate and the first support rod is raised and lowered, the first placing plate can rotate relative to the first support rod under the action of the gravity of the calf.
8. The recumbent knee joint rehabilitation training device according to claim 7, characterized in that: The first placement plate includes a first supporting portion and a first rotating portion. The first supporting portion is provided with a first groove extending along the length direction of the first placement plate. The first rotating portion is rotatably connected to the first support rod through a first rotating shaft, and the first support rod is provided with a first movable groove for the first rotating portion to rotate.
9. The recumbent knee joint rehabilitation training device according to claim 1, characterized in that: The second fixing structure includes a second placement plate and a second strap. The second placement plate is rotatably arranged on the second support rod. The second strap is detachably arranged on the second placement plate and is used to fix the thigh on the second placement plate.
10. The recumbent knee joint rehabilitation training device according to claim 9, characterized in that: The second placement plate includes a second supporting portion and a second rotating portion. The second supporting portion is provided with a second groove extending along the length direction of the second placement plate. The second rotating portion is rotatably connected to the second support rod through a second rotating shaft. A locking nut is provided on the second rotating shaft, and a second movable groove for rotation of the second rotating portion is provided on the second support rod.