A pulley adjusting structure
By designing a pulley adjustment structure, the adjustment screw drives the pulley bracket to slide, solving the tilting problem of sliding doors and windows caused by uneven ground tracks, and achieving horizontal correction and aesthetics of the doors and windows.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- FOSHAN AOSENMU DOOR & WINDOW TECH CO LTD
- Filing Date
- 2025-06-23
- Publication Date
- 2026-06-19
AI Technical Summary
Existing sliding doors and windows are tilted due to uneven floor tracks, affecting their usability and aesthetics.
The pulley adjustment structure includes a pulley bracket, an adjustment frame, a fixed frame, and an adjustment screw. The adjustment screw drives the pulley bracket to slide relative to the fixed frame, adjusting the position of the pulley to correct the tilt of the door and window and ensure a level state.
This solves the problem of sliding doors and windows tilting due to uneven ground tracks, ensuring the aesthetics and stability of sliding doors and windows.
Smart Images
Figure CN224379630U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of door and window accessories technology, and in particular to a pulley adjustment structure. Background Technology
[0002] Sliding doors and windows are equipped with a pulley assembly at the bottom. This assembly, in conjunction with the floor track structure, guides the sliding process of the doors and windows. However, in reality, due to installation or usage issues, the two ends of the floor track may be uneven, causing the sliding doors and windows to tilt to the lower side, thus affecting their usability and aesthetics. Utility Model Content
[0003] The purpose of this utility model is to provide a pulley adjustment structure to solve one or more technical problems existing in the prior art, and at least provide a beneficial option or create conditions.
[0004] The technical solution adopted to solve the above-mentioned technical problems is as follows: a pulley adjustment structure, comprising: a pulley bracket with an adjustment shaft passing through it, wherein the pulley bracket is equipped with a pulley whose rotation center line is parallel or coincident with the axis of the adjustment shaft; an adjustment frame, located on both sides of the pulley bracket, wherein each side of the adjustment frame has an inclined hole for the two ends of the adjustment shaft to pass through and slide; a fixed frame, located on both sides of the adjustment frame, wherein each side of the fixed frame has a first sliding groove for the two ends of the adjustment shaft to pass through and slide, wherein the fixed frame is slidably disposed relative to the adjustment frame; and an adjustment screw, rotatably connected to the adjustment frame and threadedly connected to the fixed frame; rotating the adjustment screw can drive the adjustment frame to slide relative to the fixed frame, causing the sidewall of the inclined hole to push the adjustment shaft to slide within the first sliding groove, thereby driving the pulley bracket to slide relative to the fixed frame.
[0005] This technical solution has at least the following beneficial effects: When the sliding door and window are fixedly installed on the fixed frame, rotating the adjusting screw can drive the pulley bracket to slide relative to the fixed frame, and the position of the pulley bracket relative to the fixed frame is perpendicular to the adjusting shaft. Since the pulley on the pulley bracket cooperates with the ground rail, it can drive the fixed frame and the sliding door and window to move up and down relative to the ground rail. That is, when the sliding door and window tilts to one side due to uneven ground rail, the fixed frame in the pulley adjustment structure at the bottom of the tilted side of the sliding door and window can be adjusted higher, or the fixed frame in the pulley adjustment structure at the bottom of the sliding door and window on the opposite side of the tilt can be adjusted lower, so that the sliding door and window can return to a horizontal state. This can solve the problem of the sliding door and window tilting during use due to uneven ground rail, and ensure the aesthetics of the sliding door and window during use.
[0006] As a further improvement to the above technical solution, one end of the adjusting frame that is rotatably connected to the adjusting screw extends out of the fixed frame. The fixed frame does not require a cavity for the adjusting frame to slide in, and its shorter length facilitates the assembly and operation of the adjusting screw.
[0007] As a further improvement to the above technical solution, the rotatable connection between the adjusting screw and the adjusting frame is replaced with a threaded connection, and the threaded connection between the adjusting screw and the fixing frame is replaced with a rotatable connection.
[0008] As a further improvement to the above technical solution, the adjusting frame is provided with two mutually overlapping limiting blocks, and a semi-circular groove is opened on one side of the two overlapping limiting blocks. The adjusting screw is provided with limiting rotating rings on both sides respectively located in the two semi-circular grooves. This facilitates the assembly of the adjusting frame and the adjusting screw with relative rotatable connection.
[0009] As a further improvement to the above technical solution, the adjusting frame includes two adjusting plates located on the outer sides of the pulley bracket. Both adjusting plates are slidably disposed relative to the fixed frame. Two inclined holes are located on the two adjusting plates, and a slot is provided at one end of each adjusting plate. Each side of the two limiting blocks is provided with a locking block, and the two locking blocks on the same side of the two limiting blocks are engaged in the slots of the corresponding adjusting plates. This facilitates the assembly and connection of the adjusting frame and the limiting blocks.
[0010] As a further improvement to the above technical solution, the middle section of the adjusting plate is provided with a curved section, so that the distance between the ends of the two adjusting plates with the slots is less than the distance between the ends of the two adjusting plates away from the slots. This saves the operating space reserved for the movement of the limiting block.
[0011] As a further improvement to the above technical solution, the adjusting screw and the limiting rotating ring are integrally formed.
[0012] As a further improvement to the above technical solution, the pulley bracket is equipped with two pulleys, and the adjusting shaft is located between the two pulleys.
[0013] As a further improvement to the above technical solution, the fixing frame has a receiving hole in the middle for accommodating the pulley bracket. Support blocks are provided on both sides of the receiving hole. The top of the pulley bracket has clearance grooves on both sides, allowing the corresponding support blocks to extend into and swing. An arc-shaped protrusion in the center of the clearance groove guides the swing of the pulley bracket. When the pulley is adjusted to its lowest position, the arc-shaped protrusion abuts against the support block, which provides a fulcrum for the swing of the pulley bracket, ensuring that the two pulleys always maintain contact with the ground rail and bear force, thus achieving self-balancing of the pulleys.
[0014] As a further improvement to the above technical solution, a mounting bracket is also included, installed on top of the fixed frame. A pull rod is slidably arranged between the mounting bracket and the fixed frame, and a guide shaft passes through the pull rod. The mounting bracket is provided with a second sliding groove for the top of the guide shaft to slide, and the top of the fixed frame is provided with a guide groove for the bottom of the guide shaft to slide. By pulling the pull rod, under the action of the guide shaft, the first sliding groove, and the guide groove, the fixed frame can be offset relative to the mounting bracket, thereby causing the sliding door / window to be pressed sideways to achieve a sealing effect. Attached Figure Description
[0015] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:
[0016] Figure 1 This is an assembly diagram of the fixing frame, adjusting frame and pulley bracket according to an embodiment of the present utility model;
[0017] Figure 2 This is an exploded view of the fixing frame, adjusting frame, and pulley bracket according to an embodiment of the present utility model;
[0018] Figure 3 This is a schematic diagram of the overall assembly of an embodiment of the present utility model;
[0019] Figure 4 This is an overall exploded view of an embodiment of the present utility model;
[0020] Figure 5 This is a partial cross-sectional schematic diagram of the fixed frame in the climbing state in an embodiment of this utility model;
[0021] Figure 6 This is a partial cross-sectional view of the fixed frame in the lowered state in an embodiment of this utility model;
[0022] Figure 7 This is a half-sectional schematic diagram of the fixed frame in the climbing state in an embodiment of this utility model;
[0023] Figure 8 This is a half-sectional view of the fixed frame in the lowered state in an embodiment of this utility model;
[0024] Figure 9 This is a partial cross-sectional structural diagram of the support block in an embodiment of this utility model;
[0025] Figure 10 This is a schematic diagram showing the position of the support block when the fixed frame is in the climbing state in this embodiment of the utility model;
[0026] Figure 11 This is a schematic diagram of the overall structure of the fixed frame in the climbing state in an embodiment of this utility model;
[0027] Figure 12 This is a schematic diagram of the overall structure of the fixed frame in the lowered state in an embodiment of this utility model.
[0028] 100. Pulley bracket; 110. Adjusting shaft; 120. Pulley; 130. Clearance groove; 131. Arc-shaped protrusion; 200. Adjusting plate; 201. Inclined hole; 202. Slot; 203. Bending section; 204. Limiting groove; 210. Limiting block; 211. Semicircular groove; 212. Locking block; 300. Fixing frame; 310. First slide groove; 320. Receiving hole; 330. Support block; 340. Slide shaft; 341. Sleeve; 350. Guide inclined groove; 400. Adjusting screw; 410. Limiting swivel ring; 500. Mounting bracket; 510. Second slide groove; 600. Pull rod; 610. Guide shaft. Detailed Implementation
[0029] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.
[0030] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0031] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.
[0032] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.
[0033] Reference Figure 1-10 The pulley adjustment structure includes a pulley bracket 100, an adjustment frame, a fixing frame 300, and an adjustment screw 400.
[0034] An adjusting shaft 110 is inserted through the middle of the pulley bracket 100, with both ends of the adjusting shaft 110 extending out from the front and rear sides of the pulley bracket 100, respectively. A pulley 120 is installed on each side of the pulley bracket 100, with the rotation center line of the pulley 120 relative to the pulley bracket 100 parallel to the axis of the adjusting shaft 110.
[0035] A receiving hole 320 is provided in the middle of the fixing frame 300, and the receiving hole 320 penetrates the top and bottom of the fixing frame 300. Sliding grooves are provided on both the front and rear sides of the bottom of the fixing frame 300, with the length direction of the sliding grooves being left and right, and both ends of the sliding grooves penetrating the left and right ends of the fixing frame 300. The front sliding groove is connected to the front side of the receiving hole 320, and the rear sliding groove is connected to the rear side of the receiving hole 320. The adjusting frame includes two adjusting plates 200 and two limiting blocks 210. The two adjusting plates 200 are slidably disposed in the two sliding grooves, and the right ends of the two adjusting plates 200 extend out of the right end of the fixing frame 300 and are connected by the two limiting blocks 210. The pulley bracket 100 is accommodated in the receiving hole 320. This positions the two adjusting plates 200 on the front and rear sides of the pulley bracket 100, while the front and rear sides of the fixing frame 300 are located on opposite sides of the two adjusting plates 200.
[0036] The adjusting plate 200 has an inclined hole 201, which is inclined to the left or right. The receiving hole 320 has a first sliding groove 310 on both the front and rear sides, and both first sliding grooves 310 extend to the front and rear sides of the fixing frame 300. The length direction of the first sliding groove 310 is vertical.
[0037] The front end of the adjusting shaft 110 extends from the front side of the pulley bracket 100 and passes sequentially through the inclined hole 201 and the receiving hole 320 of the adjusting plate 200 located on the front side, respectively, into the first sliding groove 310 located on the front side. The rear end of the adjusting shaft 110 extends from the rear side of the pulley bracket 100 and passes sequentially through the inclined hole 201 and the receiving hole 320 of the adjusting plate 200 located on the rear side, respectively, into the first sliding groove 310 located on the rear side.
[0038] When the two adjusting plates 200 move left and right relative to the fixed frame 300, the side wall of the inclined hole 201 can push the adjusting shaft 110 to slide on the first slide groove 310, thereby enabling the adjusting shaft 110 to drive the pulley bracket 100 to move up and down relative to the fixed frame 300.
[0039] In other embodiments, the number of pulleys 120 mounted on the pulley bracket 100 may be one or more. In other embodiments, the number of adjusting shafts 110 may also be the same as the number of pulleys 120 mounted on the pulley bracket 100, with each pulley 120 mounted on the pulley bracket 100 via an adjusting shaft 110. In this case, the rotation center line of the pulley 120 coincides with the axis of the adjusting shaft 110. Correspondingly, the number of inclined holes 201 on the adjusting plate 200 is the same as the number of adjusting shafts 110 and they are arranged in a one-to-one correspondence. The number of first sliding grooves 310 on the front and rear sides of the fixing frame 300 is also the same as the number of adjusting shafts 110 and they are arranged in a one-to-one correspondence.
[0040] Specifically, a slot 202 is provided at the right end of the adjusting plate 200 extending from the fixing frame 300, and the slot 202 passes through the front and rear sides of the adjusting plate 200. Two limiting blocks 210 fit together in the vertical direction, and a semi-circular groove 211 is provided on the side of the two limiting blocks 210 that are close to each other. A limiting rotating ring 410 is provided in the middle of the adjusting screw 400, and the limiting rotating ring 410 is integrally formed with the adjusting screw 400. When one side of the limiting rotating ring 410 is placed into the semi-circular groove 211 of one limiting block 210, and then the two limiting blocks 210 are fitted together, the other side of the limiting rotating ring 410 can be placed in the semi-circular groove 211 of the other limiting block 210. Thus, the position of the limiting rotating ring 410 is restricted by the two semi-circular grooves 211, and the two semi-circular grooves 211 allow the limiting rotating ring 410 to rotate within them.
[0041] Both front and rear sides of the two limiting blocks 210 are provided with protruding locking blocks 212. The two locking blocks 212 on the same side of the two limiting blocks 210 are engaged in the locking grooves 202 on the same side. The ends of the two adjusting plates 200 with locking grooves 202 jointly clamp the two limiting blocks 210, so that the two adjusting plates 200 and the two limiting blocks 210 are connected and assembled with each other, completing the rotational connection assembly of the two limiting blocks 210 and the adjusting screw 400. Threaded holes are provided at both ends of the fixing frame 300. The threaded holes are adapted to the adjusting screw 400, so that the adjusting screw 400 can be screwed into the threaded holes at the left or right end of the fixing frame 300 as needed, completing the threaded connection assembly of the adjusting screw 400 and the fixing frame 300. The end of the adjusting screw 400 is formed with a hexagonal groove or cross groove structure to facilitate the rotation of the adjusting screw 400. By rotating the adjusting screw 400, the two adjusting plates 200 can be driven to slide synchronously relative to the fixed frame 300. Under the action of the inclined hole 201 and the first sliding groove 310, the pulley bracket 100 can slide up and down relative to the fixed frame 300, thereby realizing the height adjustment of the pulley 120 relative to the fixed frame 300.
[0042] Furthermore, the front-to-back width of the limiting block 210 is designed to be smaller than the distance between the two adjusting plates 200. In this case, the portion of the two adjusting plates 200 extending out of the fixing frame 300 on the right side has a curved section 203, making the distance between the right ends of the two adjusting plates 200 clamping the two limiting blocks 210 smaller than the distance between the two adjusting plates 200 and one end of the limiting block 210. The two adjusting plates 200 are arranged parallel to each other on the left and right sides of the curved section 203. This reduces the space required for the movement of the limiting block 210, or allows for installation in narrower spaces, and also allows the locking block 212 to extend a certain distance out of the locking slot 202, thereby improving the assembly stability of the two adjusting plates 200 and the two limiting blocks 210.
[0043] In addition, a through hole structure communicating with the corresponding semi-circular groove 211 is provided on the opposite side of the two limiting blocks 210. The through hole structure allows the limiting ring 410 to be partially exposed outside the two limiting blocks 210, thereby reducing the height dimension of the two limiting blocks 210 when they are covered. At the same time, it can also reduce the friction of the limiting ring 410 rotating in the two semi-circular grooves 211, so as to improve the smoothness and stability of the rotation of the adjusting screw 400.
[0044] In other embodiments, the right sides of the two adjusting plates 200 may not extend beyond the right end of the fixing frame 300. Instead, a separate accommodating space may be provided within the fixing frame 300 to allow the two limiting blocks 210 connecting the two adjusting plates 200 to move left and right relative to the fixing frame 300. In this case, the adjusting screw 400 is first threadedly connected to one end of the fixing frame 300, and then rotatably connected to the two limiting blocks 210. In this case, the limiting rotating ring 410 can be snapped onto the adjusting screw 400 after the adjusting screw 400 is threadedly connected to the fixing frame 300.
[0045] In other embodiments, the two limiting blocks 210 may not have semicircular grooves 211, but instead are threadedly connected to the adjusting screw 400 as a whole. The threaded connection between the adjusting frame and the adjusting screw 400 is located outside the end of the fixed frame 300, and the adjusting screw 400 is rotatably connected to the fixed frame 300. When the adjusting screw 400 is rotated, the adjusting frame and the fixed frame 300 can also slide relative to each other left and right. Furthermore, in this embodiment, the two limiting blocks 210 and the two adjusting plates 200 can be made as a single unit.
[0046] Furthermore, support blocks 330 are protruding from the top center of both the front and rear sides of the receiving hole 320. Relief grooves 130 are provided on both the front and rear sides of the top of the pulley bracket 100. The bottom surface of the relief groove 130 has an arc-shaped protrusion 131, the center line of which coincides with the axis of the adjusting shaft 110. When the pulley bracket 100 is at its highest position relative to the fixed frame 300, the support block 330 is positioned in the corresponding relief groove 130. When the two pulleys 120 or the fixed frame 300 are subjected to uneven external forces, the pulley bracket 100 can swing within the receiving hole 320 around the axis of the adjusting shaft 110. At this time, the arc-shaped protrusion 131 abuts against and swings at the bottom of the support block 330, allowing the support block 330 to provide a fulcrum for the swing of the pulley bracket 100, thus ensuring that the two pulleys always maintain contact with the ground rail and achieve pulley self-balancing.
[0047] In addition, when the adjusting pulley bracket 100 moves down from the highest position relative to the fixed frame 300, the arc protrusion 131 does not contact the support block 330, but the adjusting shaft 110, under the constraint of the side wall of the first slide groove 310 and the inclined hole 201, can also allow the pulley bracket 100 to tilt around the axis of the adjusting shaft 110 to achieve the self-balancing of the pulley.
[0048] The pulley adjustment structure also includes a mounting bracket 500 and a tie rod 600. The mounting bracket 500 includes a top plate and two side plates connected to the front and rear ends of the top plate and extending downwards. The two side plates are located on the front and rear sides of the fixed frame 300, respectively. Sleeves 341 and sliding shafts 340 are inserted through both ends of the fixed frame 300. The length direction of the sleeves 341 is both in the front-rear direction. Limiting grooves 204 are formed at both ends of the adjusting plate 200. The two ends of the sleeves 341 pass through the two ends of the fixed frame 300 and are sequentially inserted into the corresponding limiting grooves 204 and side plates. The sliding shafts 340 are riveted after passing through the sleeves 341. This assembles and connects the fixed frame 300 and the mounting bracket 500. When the adjusting screw 400 is rotated, causing the adjusting plate 200 to slide relative to the fixed frame 300, the sliding shaft 340 slides left and right relative to the adjusting plate 200 in the limiting groove 204, thereby preventing interference. In addition, due to the limiting effect of the sleeve 341 on the adjusting plate 200, the stability of the sliding of the adjusting plate 200 relative to the fixed frame 300 can be guaranteed.
[0049] The tie rod 600 is located between the top plate of the mounting bracket 500 and the top of the fixing frame 300. Both the tie rod 600 and the mounting bracket 500 have square holes in the middle to allow two pulleys 120 to protrude from the top of the mounting bracket 500.
[0050] The top plate of the mounting bracket 500 has second sliding grooves 510 on both the left and right sides, with the length direction being left and right. The top of the fixing bracket 300 has guide grooves 350 on both the left and right sides, with one end of the guide grooves 350 inclined forward or backward. Guide shafts 610 pass through both ends of the pull rod 600. The top of the guide shaft 610 protrudes from the top surface of the pull rod 600 and is fitted with a first rolling sleeve, which rolls within the corresponding second sliding groove 510. The bottom of the guide shaft 610 protrudes from the bottom surface of the pull rod 600 and is fitted with a second rolling sleeve, which rolls within the corresponding guide groove 350.
[0051] When the pull rod 600 is pulled left and right, the guide shaft 610 moves left and right under the guidance of the second slide groove 510. The guide shaft 610 acts on the side wall of the guide inclined groove 350, which pushes the fixed frame 300 and its pulley bracket 100 to shift back and forth as a whole. This can drive the sliding door and window installed on the mounting bracket 500 to achieve lateral pressure relative to the ground track, thereby improving the sealing performance of the sliding door and window.
[0052] Reference Figure 11-12 For example, when using the pulley adjustment structure, the sliding door / window is mounted on the mounting bracket 500. A corner bracket is installed at one end of the mounting bracket 500. One end of the pull rod 600 is connected to a transmission steel plate in the corner bracket, and the other end of the transmission steel plate is connected to a transmission rod connector. The transmission rod connector is connected to the transmission rod. When the transmission rod is slid by the handle or other operating components, the pull rod 600 can be moved left or right by the transmission steel plate, thus achieving lateral pressure of the sliding door / window relative to the ground track.
[0053] Reference Figure 11 When sliding doors and windows become unstable due to excessive height off the ground, the fixed bracket 300, which is fixedly connected to the sliding door and window, is in a raised position. By rotating the adjusting screw 400, the fixed bracket 300 can be moved downward relative to the pulley bracket 100, adjusting the distance between the sliding door / window and the ground track, thereby solving the problem of instability of the sliding door / window.
[0054] Reference Figure 12 When sliding doors and windows tilt to one side due to uneven ground tracks, the fixed bracket 300 in the bottom pulley adjustment structure of the tilted side of the sliding door and window can be adjusted higher, or the fixed bracket 300 in the bottom pulley adjustment structure of the opposite tilted side of the sliding door and window can be adjusted lower, so that the sliding door and window can return to a level state. This can solve the problem of sliding doors and windows tilting during use due to uneven ground tracks and ensure the aesthetics of the sliding doors and windows during use.
[0055] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.
Claims
1. A pulley adjustment structure, characterized in that, include: A pulley bracket is provided with an adjusting shaft, and the pulley bracket is equipped with a pulley whose rotation center line is parallel to or coincides with the axis of the adjusting shaft; The adjustment frame is located on both sides of the pulley bracket. Inclined holes are provided on both sides of the adjustment frame for the two ends of the adjustment shaft to pass through and slide. The fixing frame is located on both sides of the adjustment frame. Each side of the fixing frame has a first sliding groove for the two ends of the adjustment shaft to pass through and slide. The fixing frame is slidably arranged relative to the adjustment frame. An adjusting screw is rotatably connected to the adjusting frame and is also threadedly connected to the fixed frame. Rotating the adjusting screw can cause the adjusting frame to slide relative to the fixed frame, so that the inclined hole sidewall pushes the adjusting shaft to slide in the first slide groove, thereby causing the pulley bracket to slide relative to the fixed frame.
2. The pulley adjustment structure according to claim 1, characterized in that: One end of the adjusting frame, which is rotatably connected to the adjusting screw, extends out of the fixed frame.
3. The pulley adjustment structure according to claim 2, characterized in that: The rotatable connection between the adjusting screw and the adjusting frame is replaced with a threaded connection, and the threaded connection between the adjusting screw and the fixing frame is replaced with a rotatable connection.
4. The pulley adjustment structure according to claim 1, characterized in that: The adjustment frame is provided with two mutually overlapping limiting blocks. A semi-circular groove is provided on one side of the two limiting blocks that overlap each other. The adjustment screw is provided with limiting rotating rings on both sides that are respectively located in the two semi-circular grooves.
5. The pulley adjustment structure according to claim 4, characterized in that: The adjustment frame includes two adjustment plates located on the outer sides of the pulley bracket. Both adjustment plates are slidably disposed relative to the fixed frame. Two inclined holes are located on the two adjustment plates respectively. A slot is provided at one end of each of the two adjustment plates. A locking block is provided on both sides of each of the two limiting blocks. The two locking blocks on the same side of the two limiting blocks are locked together in the slots of the corresponding adjustment plates.
6. The pulley adjustment structure according to claim 5, characterized in that: The middle section of the adjustment plate is provided with a curved section, so that the distance between the ends of the two adjustment plates with the slots is less than the distance between the ends of the two adjustment plates away from the slots.
7. The pulley adjustment structure according to claim 4, characterized in that: The adjusting screw and the limiting rotating ring are integrally formed.
8. The pulley adjustment structure according to claim 1, characterized in that: The pulley bracket is equipped with two pulleys, and the adjusting shaft is located between the two pulleys.
9. The pulley adjustment structure according to claim 8, characterized in that: The fixed frame has a receiving hole in the middle for the pulley bracket to be accommodated. Support blocks are provided on both sides of the receiving hole. The top of the pulley bracket has clearance grooves on both sides for the corresponding support blocks to extend into and swing. The clearance grooves have arc-shaped protrusions in the middle for guiding the pulley bracket to swing.
10. The pulley adjustment structure according to claim 1, characterized in that: It also includes a mounting bracket installed on the top of the fixed frame, a tie rod slidably disposed between the mounting bracket and the fixed frame, a guide shaft passing through the tie rod, a second sliding groove for the top of the guide shaft to slide in, and a guide groove for the bottom of the guide shaft to slide in at the top of the fixed frame.