A blood drawing auxiliary device for physical examination of the elderly

Abstract

The application provides an old people physical examination blood drawing auxiliary device, which comprises a supporting shell, a fixing frame is arranged at the bottom of the supporting shell, two parallel and longitudinally-through sliding grooves are arranged on the supporting shell, clamping plates are slidably arranged in the two sliding grooves, a movable frame is slidably arranged in the supporting shell, a supporting plate is arranged at one end of the movable frame, a linkage assembly connected with the two clamping plates is arranged on the movable frame, the two clamping plates are driven to slide and open and close along the two sliding grooves through the linkage assembly during the sliding of the movable frame, a first locking assembly connected with the movable frame is arranged in the supporting shell, and the position of the movable frame is locked through the first locking assembly. The device can quickly fix the arm of a patient in multiple directions, effectively avoids the inconvenience of blood drawing caused by the movement of the arm of the patient during blood drawing, and improves the safety during blood drawing.

Description

Technical Field

[0001] This invention specifically relates to an auxiliary device for blood drawing during physical examinations of the elderly. Background Technology

[0002] Regular physical examinations are essential for the elderly, especially those over 60, particularly those with chronic complications such as cardiovascular and cerebrovascular diseases. These individuals should have a check-up every three to four months. Each examination includes a basic physical examination and blood tests. However, elderly patients often experience uncontrollable arm tremors during blood draws, which can hinder the aspiration process.

[0003] For example, Chinese patent number 202222323965.7 provides a medical blood drawing table. This medical blood drawing table has a fixed support and arm placement groove designed on the table surface to fix the arm position. The patient's arm can be tightened by four straps to prevent some emotionally unstable patients from being pricked by the blood drawing needle due to moving around during the blood drawing process.

[0004] However, most existing devices can only fix the arm in one direction, and the fixation is relatively cumbersome and inconvenient to quickly fix the arm of elderly patients in multiple directions. This means that the arm of elderly patients may still move to some extent during the blood draw, which reduces the safety of the blood draw process. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a blood-drawing auxiliary device for elderly physical examinations. This addresses the technical problem mentioned in the background section: traditional blood-drawing auxiliary devices for elderly physical examinations are inconvenient for quickly and effectively fixing the elderly patient's arm in multiple directions, which can lead to some degree of arm movement during the blood-drawing process and reduce safety.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a blood-drawing auxiliary device for elderly physical examinations, comprising:

[0007] A support shell, the bottom of which is provided with a fixing frame, and two parallel and longitudinally penetrating sliding grooves are provided on the support shell;

[0008] There are two clamping plates arranged opposite each other, and they are respectively slidably locked in the two sliding grooves;

[0009] A movable frame is slidably disposed within the support shell along a direction perpendicular to the slide groove, and a support plate is provided at one end of the movable frame;

[0010] A linkage component is mounted on the movable frame and connected to the two clamping plates. During the sliding process, the movable frame drives the two clamping plates to slide and open / close along the two sliding grooves respectively via the linkage component.

[0011] A first locking component is disposed within the support housing and connected to the movable frame to lock the position of the movable frame.

[0012] Furthermore, the linkage component includes:

[0013] The first rack is disposed at one end of the movable frame and is perpendicular to the extension direction of the slide groove;

[0014] A first gear, rotatably disposed within the support housing along its axis, and meshing with the first rack; and

[0015] There are two second racks, which are fixedly connected to the bottom of the two clamps respectively. The two second racks are symmetrical about the axis of the first rack, and both second racks mesh with the first gear.

[0016] Furthermore, a positioning frame is provided at the bottom of the support shell, the extension direction of the positioning frame is perpendicular to the extension direction of the slide groove, and the movable frame is slidably engaged in the positioning frame.

[0017] Furthermore, the first locking component includes:

[0018] A ratchet rack is arranged on the movable frame along the axis of the movable frame;

[0019] A mounting shaft, rotatably disposed within the support housing along its axis, has an eccentrically mounted pawl that engages with a ratchet rack. A torsion spring is provided at the mounting point between the mounting shaft and the support housing.

[0020] A control shaft is mounted on the pawl, and an arc-shaped groove is provided on the side of the support shell. The control shaft passes through the arc-shaped groove and is connected to a first push plate.

[0021] Furthermore, one end of the movable frame is connected to a tension spring, and one end of the tension spring is fixedly connected to the support shell.

[0022] Furthermore, a first protective pad is provided on the support shell, a second protective pad is provided on the inner side of the tray, and a third protective pad is provided on the inner side of the two clamping plates.

[0023] Furthermore, a pressure band is provided at one end of the movable frame near the tray, with both ends of the pressure band extending to the inner bottom surface of the movable frame. The movable frame is also provided with a winding mechanism and a tightening mechanism respectively connected to both ends of the pressure band. During the sliding process, the movable frame automatically winds one end of the pressure band through the winding mechanism, and the other end of the pressure band can be manually tightened through the tightening mechanism.

[0024] Furthermore, the winding mechanism includes:

[0025] The first winding wheel is rotatably disposed at the bottom of the movable frame along its axis and is connected to one end of the pressure belt;

[0026] The first synchronizing pulley is mounted on the first winding pulley;

[0027] A second synchronous pulley, rotatably disposed along its axis at the bottom end of the movable frame away from the support plate, and connected to the first synchronous pulley via a synchronous belt, wherein a second gear is provided on the second synchronous pulley; and

[0028] The third rack is fixedly disposed in the support shell along the axis of the movable frame, and the second gear meshes with the third rack.

[0029] Furthermore, the tightening mechanism includes:

[0030] The second winding wheel is rotatably disposed at the bottom of the movable frame along its axis and is connected to the other end of the pressure belt;

[0031] A control wheel is located at the bottom of the second winding wheel and is exposed outside the movable frame; and

[0032] A second locking component is disposed within the movable frame and connected to the second winding wheel to lock the position of the rotated second winding wheel.

[0033] Furthermore, the second locking component includes:

[0034] A first ratchet disc is disposed at the bottom of the second winding wheel, and a mounting post is also disposed at the bottom of the second winding wheel;

[0035] The second ratchet disc is slidably sleeved on the mounting post along the axis of the mounting post and meshes with the first ratchet disc. The second ratchet disc is provided with a positioning ring and a second press plate, and the second press plate protrudes out of the movable frame.

[0036] The elastic element has one end abutting against the bottom surface of the second ratchet disc and the other end abutting against the control wheel; and

[0037] A guide rod is provided at the bottom of the movable frame, and the positioning ring is slidably sleeved on the guide rod.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. In use, the device is fixed in the blood-drawing area by a fixing frame. The patient places their arm between two clamps and moves their elbow backward, causing the support plate to move. This, in turn, causes the movable frame to slide within the support shell. During the sliding process, the movable frame drives the two clamps to close through a linkage component, clamping the patient's arm. The position of the movable frame is fixed by a first locking component. Thus, the two clamps clamp the patient's arm, preventing it from swinging during blood drawing. The support plate also fixes the patient's elbow, preventing it from moving backward. This allows for quick and multi-directional fixation of the patient's arm, effectively preventing inconvenience caused by arm movement during blood drawing and improving the safety of the blood drawing process.

[0040] 2. In use, as the elbow is moved backward, the movable frame moves, causing the second gear and the third rack to move relative to each other. This drives the second gear and the second synchronous pulley above it to rotate. During rotation, the second synchronous pulley controls the rotation of the first synchronous pulley via a synchronous belt, causing the first winding wheel to wind the tourniquet, facilitating quick location of the patient's arm veins by medical personnel. When the patient's arm is thin, the second winding wheel can be tightened by turning the control wheel. During rotation, the second winding wheel's position is locked by the engagement of the first and second ratchet plates, preventing reverse rotation. After blood draw, pressing down on the second button moves the second ratchet plate downward, disengaging it from the first ratchet plate, thus loosening the tourniquet and allowing the patient to easily remove their arm, improving the device's functionality. Attached Figure Description

[0041] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly described below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0042] Figure 1 This invention provides a three-dimensional structural schematic diagram of a blood-drawing auxiliary device for elderly physical examinations.

[0043] Figure 2 This is a schematic diagram of the bottom structure of a blood-drawing auxiliary device for elderly physical examinations according to the present invention;

[0044] Figure 3 This is a schematic diagram of the movable frame in a blood collection auxiliary device for elderly physical examinations according to the present invention;

[0045] Figure 4 This is a schematic diagram of the internal structure of the support shell in a blood-drawing auxiliary device for elderly physical examinations according to the present invention;

[0046] Figure 5 This is a schematic diagram of the pawl structure in a blood-drawing auxiliary device for elderly physical examinations according to the present invention;

[0047] Figure 6 This is a schematic diagram of the installation structure of the tourniquet in a blood-drawing auxiliary device for elderly physical examinations according to the present invention.

[0048] Figure label:

[0049] 101. Support shell; 102. First protective pad; 103. Slide groove; 104. Fixing frame; 105. First gear; 106. Positioning frame; 107. Third rack; 108. Arc groove;

[0050] 201. Movable frame; 202. Support plate; 203. Second protective pad; 204. Ratchet; 205. First rack; 206. Tension spring; 207. Guide rod;

[0051] 301. Clamping plate; 302. Third protective pad; 303. Second rack;

[0052] 401. Mounting shaft; 402. Control shaft; 403. Pawl; 404. First button; 405. Torsion spring;

[0053] 501. Pressure belt; 502. First winding pulley; 503. First synchronizing pulley; 504. Second gear; 505. Second synchronizing pulley; 506. Synchronizing belt;

[0054] 601. Second winding wheel; 602. Mounting post; 603. First ratchet disc; 604. Control wheel;

[0055] 701. Second ratchet disc; 702. Positioning ring; 703. Second push plate; 704. Elastic element. Detailed Implementation

[0056] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0057] Example:

[0058] like Figure 1 , 2As shown, this invention provides a blood-drawing auxiliary device for elderly patients undergoing physical examinations. It includes a support shell 101, a fixing frame 104 at the bottom of the support shell 101, and two parallel and longitudinally penetrating grooves 103 on the support shell 101. Each groove 103 contains a clamping plate 301, which is slidably engaged with the other two clamping plates. The clamping plates 301 can slide within the two grooves 103, and the movement of the clamping plates 301 is positioned by the grooves 103, thereby tightening the patient's arm.

[0059] like Figure 1 , 2 As shown in Figure 3, in this embodiment, a movable frame 201 is slidably arranged inside the support shell 101 in a direction perpendicular to the slide groove 103. A support plate 202 is provided at one end of the movable frame 201. A linkage assembly connected to two clamping plates 301 is provided on the movable frame 201. During the sliding process, the movable frame 201 drives the two clamping plates 301 to slide open and close along the two slide grooves 103 respectively through the linkage assembly. The linkage assembly includes a first rack 205 at one end of the movable frame 201. The first rack 205 is perpendicular to the extension direction of the slide groove 103. A rotatable first gear 105 is provided inside the support shell 101. The first gear 105 meshes with the first rack 205. A second rack 303 is fixedly provided at the bottom of each of the two clamping plates 301. The two second racks 303 are symmetrical about the axis of the first rack 205, and both second racks 303 mesh with the first gear 105.

[0060] A positioning frame 106 is provided at the bottom of the support shell 101. The extension direction of the positioning frame 106 is perpendicular to the extension direction of the slide groove 103. The movable frame 201 is slidably locked in the positioning frame 106, so that the movable frame 201 can slide within the support shell 101 along the extension direction of the positioning frame 106. The patient can place their elbow on one side of the support plate 202 and move the support plate 202 by moving the elbow backward, thereby causing the movable frame 201 to move. During the movement, the movable frame 201 drives the first gear 105 to rotate through the first rack 205, which in turn drives the two second racks 303 to slide simultaneously through the first gear 105, so that the two clamps 301 close together to clamp the patient's arm.

[0061] like Figure 2 , 3As shown in Figures 4 and 5, in this embodiment, a first locking component connected to the movable frame 201 is provided inside the support shell 101, and the position of the movable frame 201 is locked by the first locking component. The first locking component includes a ratchet rack 204 arranged along the axis of the movable frame 201. A rotatable mounting shaft 401 is provided inside the support shell 101. A pawl 403 is eccentrically provided on the mounting shaft 401. The pawl 403 is engaged with the ratchet rack 204. A torsion spring 405 is provided at the mounting point between the mounting shaft 401 and the support shell 101. A control shaft 402 is provided on the pawl 403. An arc-shaped groove 108 is opened on the side of the support shell 101. The control shaft 402 passes through the arc-shaped groove 108 and is connected to a first push plate 404.

[0062] During the sliding of the movable frame 201, the ratchet 204 can move relative to the pawl 403, and the mounting shaft 401 is rotated and reset by the torsion spring 405, so that the pawl 403 is locked on the ratchet 204, and the position of the movable frame 201 is locked in one direction. This effectively prevents the splint 301 and the support plate 202 from moving in opposite directions. The splint 301 fixes the patient's arm, and the support plate 202 fixes the patient's elbow, so as to quickly and stably fix the patient's arm in multiple directions, effectively avoiding blood collection failure caused by the movement of the patient's arm during the blood collection process.

[0063] Furthermore, a tension spring 206 is connected to one end of the movable frame 201, and one end of the tension spring 206 is fixedly connected to the support shell 101. During the sliding process of the movable frame 201, the tension spring 206 is stretched. After blood drawing is completed, the first press plate 404 can be pressed along the arc groove 108 to drive the pawl 403 to rotate along the mounting shaft 401 and disengage from the ratchet rack 204, thereby releasing the fixation on the movable frame 201. Under the action of the tension spring 206, the movable frame 201 can be controlled to reset. During the reset process of the movable frame 201, the two clamps 301 are opened through the linkage component, which can quickly release the fixation on the patient's arm, further improving the efficiency of blood drawing.

[0064] like Figure 1 As shown, in this embodiment, a first protective pad 102 is provided on the support shell 101, a second protective pad 203 is provided on the inner side of the support plate 202, and a third protective pad 302 is provided on the inner side of the two clamps 301, so as to provide multi-faceted protection for the patient's arm, avoid causing pinching injury to the patient's arm, and improve the comfort when fixing the arm.

[0065] like Figure 3 , 4As shown in Figure 6, in this embodiment, a pressure band 501 is provided at one end of the movable frame 201 near the support plate 202. Both ends of the pressure band 501 extend to the inner bottom surface of the movable frame 201. The movable frame 201 is also provided with a winding mechanism and a tightening mechanism respectively connected to both ends of the pressure band 501. During the sliding process, the movable frame 201 automatically winds one end of the pressure band 501 through the winding mechanism, and can also manually tighten the other end of the pressure band 501 through the tightening mechanism. The winding mechanism includes a first winding wheel 502 rotatably disposed at the bottom of the movable frame 201 along its axis. The first winding wheel 502 is connected to one end of the pressure belt 501. A first synchronous wheel 503 is disposed on the first winding wheel 502. A rotatable second synchronous wheel 505 is disposed at the bottom of the movable frame 201 away from the support plate 202. The second synchronous wheel 505 is connected to the first synchronous wheel 503 through a synchronous belt 506. A second gear 504 is disposed on the second synchronous wheel 505. A third rack 107 is fixedly disposed in the axial direction of the movable frame 201 inside the support shell 101. The second gear 504 meshes with the third rack 107.

[0066] When placing the arm, the patient can pass the arm through the loop formed by the compression band 501 and the movable frame 201. During the movement of the movable frame 201, the movable frame 201 drives the second gear 504 to move. During the movement, the second gear 504 drives the second synchronous pulley 505 to rotate through meshing with the third rack 107. In turn, the second synchronous pulley 505 and the synchronous belt 506 drive the first synchronous pulley 503 and the first winding pulley 502 above it to rotate, so as to wind one end of the compression band 501, thereby facilitating medical staff to quickly find the blood vessel and improve the efficiency of blood drawing.

[0067] like Figure 2 , 3As shown in Figure 6, in this embodiment, the tightening mechanism includes a second winding wheel 601 rotatably disposed at the bottom of the movable frame 201 along its axis. The second winding wheel 601 is connected to the other end of the pressure belt 501. A control wheel 604 is disposed at the bottom of the second winding wheel 601. The control wheel 604 is exposed outside the movable frame 201. A second locking component connected to the second winding wheel 601 is disposed inside the movable frame 201. The position of the rotated second winding wheel 601 is locked by the second locking component. The second locking assembly includes a first ratchet disc 603 disposed at the bottom of the second winding wheel 601. A mounting post 602 is also disposed at the bottom of the second winding wheel 601. A second ratchet disc 701 is slidably sleeved on the mounting post 602. The second ratchet disc 701 meshes with the first ratchet disc 603. A positioning ring 702 and a second press plate 703 are disposed on the second ratchet disc 701. The second press plate 703 protrudes out of the movable frame 201. An elastic element 704 is disposed between the second ratchet disc 701 and the control wheel 604. A guide rod 207 is disposed at the bottom of the movable frame 201. The positioning ring 702 is slidably sleeved on the guide rod 207.

[0068] When the movable frame 201 moves to its limit position, the compression band 501 can no longer contract. When the patient's arm is relatively thin, the control wheel 604 can be turned to rotate the second winding wheel 601 to wind the other end of the compression band 501, thereby manually contracting the compression band 501 to accommodate people with thin arms. When the second winding wheel 601 rotates, the elastic element 704 abuts against the second ratchet disc 701, making it engage with the first ratchet disc 603, thereby locking the second winding wheel 601 in one direction and preventing it from reversing. When it is necessary to release the compression band 501, the second button 703 can be pressed down to drive the second ratchet disc 701 to slide along the guide rod 207 and disengage from the first ratchet disc 603, thereby releasing the fixation of the second winding wheel 601 and making it easier for the patient to remove their arm.

[0069] Specific usage and beneficial effects of the present invention:

[0070] In use, the device is fixed in the blood-drawing area by the fixing frame 104. The patient places their arm between the two clamps 301 and moves their elbow backward, causing the support plate 202 to move. This causes the movable frame 201 to slide within the support shell 101. During the sliding process, the movable frame 201 drives the first gear 105 to rotate through the first rack 205. The first gear 105, in conjunction with the two second racks 303, causes the two clamps 301 to close, clamping the patient's arm. The position of the movable frame 201 is fixed by the engagement of the pawl 403 and the ratchet 204. The clamps 301 clamp the patient's arm, preventing it from swinging during blood drawing. The support plate 202 also fixes the patient's elbow, preventing it from moving backward. This allows for quick and multi-directional fixation of the patient's arm, effectively preventing inconvenience caused by arm movement during blood drawing and improving the safety of the blood drawing process. When it is necessary to remove the arm, press the first button 404 to disengage the pawl 403 from the ratchet rack 204.

[0071] When the device is in use, the second gear 504 and the third rack 107 move relative to each other as the elbow moves backward to move the movable frame 201. This causes the second gear 504 and the second synchronous pulley 505 above it to rotate. During the rotation of the second synchronous pulley 505, the first synchronous pulley 503 is controlled to rotate via the synchronous belt 506, so that the first winding pulley 502 rotates to wind the pressure band 501, making it easier for medical staff to quickly locate the patient's arm veins. Furthermore, when the patient's arm is relatively thin, the control wheel 604 can be turned to rotate the second winding wheel 601 to tighten one end of the pressure band 501. During the rotation of the second winding wheel 601, its position is locked by the cooperation of the first ratchet disc 603 and the second ratchet disc 701 to prevent the second winding wheel 601 from reversing. After the blood draw is completed, pressing down on the second button 703 will cause the second ratchet disc 701 to move downward and disengage from the first ratchet disc 603, which will loosen the pressure band 501 and make it easier for the patient to remove their arm, thus improving the functionality of the device.

[0072] The foregoing has shown and described the basic principles and main features of the present invention and its advantages. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments.

Claims

1. A blood-drawing auxiliary device for elderly physical examinations, characterized in that, Including: Support shell (101), the bottom of the support shell (101) is provided with a fixing frame (104), and two parallel and longitudinally penetrating sliding grooves (103) are opened on the support shell (101). There are two clamping plates (301) arranged opposite each other, and they are respectively slidably locked in the two sliding grooves (103); The movable frame (201) is slidably disposed in the support shell (101) in a direction perpendicular to the slide groove (103), and a support plate (202) is provided at one end of the movable frame (201). A linkage component is mounted on the movable frame (201) and connected to the two clamping plates (301). During the sliding process, the movable frame (201) drives the two clamping plates (301) to slide open and close along the two sliding grooves (103) respectively via the linkage component; and A first locking component is disposed within the support shell (101) and connected to the movable frame (201) to lock the position of the movable frame (201); The first locking component includes: A ratchet rack (204) is arranged on the movable frame (201) along the axis of the movable frame (201); A mounting shaft (401) is rotatably disposed within the support housing (101) along its axis. A pawl (403) is eccentrically disposed on the mounting shaft (401), and the pawl (403) is engaged with the ratchet rack (204). A torsion spring (405) is disposed at the mounting point between the mounting shaft (401) and the support housing (101). A control shaft (402) is disposed on the pawl (403). An arc-shaped groove (108) is provided on the side of the support shell (101). The control shaft (402) passes through the arc-shaped groove (108) and is connected to a first button (404). The movable frame (201) is provided with a pressure band (501) at one end near the tray (202). Both ends of the pressure band (501) extend to the inner bottom surface of the movable frame (201). The movable frame (201) is also provided with a winding mechanism and a tightening mechanism respectively connected to the two ends of the pressure band (501). During the sliding process, the movable frame (201) automatically winds one end of the pressure band (501) through the winding mechanism, and can also manually tighten the other end of the pressure band (501) through the tightening mechanism.

2. The blood-drawing auxiliary device for elderly physical examinations according to claim 1, characterized in that, The linkage components include: The first rack (205) is disposed at one end of the movable frame (201) and is perpendicular to the extending direction of the slide (103); The first gear (105) is rotatably disposed within the support housing (101) along its axis and meshes with the first rack (205); and There are two second racks (303), which are fixedly connected to the bottom of the two clamps (301) respectively. The two second racks (303) are symmetrical about the axis of the first rack (205), and both second racks (303) mesh with the first gear (105).

3. The blood-drawing auxiliary device for elderly physical examinations according to claim 1, characterized in that: The bottom of the support shell (101) is provided with a positioning frame (106), the extension direction of the positioning frame (106) is perpendicular to the extension direction of the slide groove (103), and the movable frame (201) is slidably locked in the positioning frame (106).

4. The blood-drawing auxiliary device for elderly physical examinations according to claim 1, characterized in that: One end of the movable frame (201) is connected to a tension spring (206), and one end of the tension spring (206) is fixedly connected to the support shell (101).

5. The blood-drawing auxiliary device for elderly physical examinations according to claim 1, characterized in that: The support shell (101) is provided with a first protective pad (102), the inner side of the tray (202) is provided with a second protective pad (203), and the inner side of the two clamps (301) is provided with a third protective pad (302).

6. The blood-drawing auxiliary device for elderly physical examinations according to claim 1, characterized in that, The winding mechanism includes: The first winding wheel (502) is rotatably disposed at the bottom of the movable frame (201) along its axis and is connected to one end of the pressure belt (501); The first synchronous pulley (503) is disposed on the first winding pulley (502); The second synchronous pulley (505) is rotatably disposed along its axis at one end of the bottom of the movable frame (201) away from the tray (202), and is connected to the first synchronous pulley (503) via a synchronous belt (506). A second gear (504) is disposed on the second synchronous pulley (505); and The third rack (107) is fixedly disposed in the support shell (101) along the axial direction of the movable frame (201), and the second gear (504) meshes with the third rack (107).

7. The blood-drawing auxiliary device for elderly physical examinations according to claim 6, characterized in that, The tightening mechanism includes: The second winding wheel (601) is rotatably disposed at the bottom of the movable frame (201) along its axis and connected to the other end of the pressure belt (501); A control wheel (604) is disposed at the bottom of the second winding wheel (601) and exposed outside the movable frame (201); and The second locking component is disposed within the movable frame (201) and connected to the second winding wheel (601) to lock the position of the second winding wheel (601) after rotation.

8. The blood-drawing auxiliary device for elderly physical examinations according to claim 7, characterized in that, The second locking component includes: A first ratchet disc (603) is provided at the bottom of the second winding wheel (601), and a mounting post (602) is also provided at the bottom of the second winding wheel (601). The second ratchet disc (701) is slidably sleeved on the mounting post (602) along the axis of the mounting post (602) and meshes with the first ratchet disc (603). The second ratchet disc (701) is provided with a positioning ring (702) and a second press plate (703), and the second press plate (703) protrudes out of the movable frame (201). The elastic element (704) abuts at one end against the bottom surface of the second ratchet disc (701) and at the other end against the control wheel (604); and A guide rod (207) is provided at the bottom of the movable frame (201), and the positioning ring (702) is slidably sleeved on the guide rod (207).

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