A button sewing machine

Abstract

The application relates to the technical field of a button sewing machine, and discloses a button sewing machine which comprises a shell, a driving mechanism arranged on the shell, a mounting block arranged on the driving mechanism, a rotating structure arranged on the shell, two rotating strips arranged on the rotating structure, the rotating strips being arranged on the two sides of the mounting block, a fixing tool arranged on the rotating strips, a fixing assembly arranged on the rotating strips and used for limiting the movement of the fixing tool, a locking structure arranged on the mounting block and used for locking the fixing tool, and an unlocking structure arranged on the rotating strips and used for driving the locking structure to be unlocked. The button sewing machine is used for realizing the replacement of the fixing tool through the rotating structure, the unlocking structure and the fixing assembly, moving the fixing tool from another rotating strip to the mounting block, thereby realizing the replacement of the fixing tool, and enabling one button sewing machine to meet the replacement of buttons of different models.

Description

Technical Field

[0001] This application relates to the technical field of button attaching machines, and in particular to a button attaching machine. Background Technology

[0002] A button sewing machine is a specialized automatic sewing machine mainly used for sewing buttons with regular shapes. Button sewing machines can sew buttons or labels onto fabrics and are widely used in button processing for clothing, advertising banners, headwear, belts, bracelets, bags, etc.

[0003] In related technologies, a button attaching machine includes a housing, a drive mechanism on the housing, an mounting block on the drive mechanism, a fixing fixture on the mounting block for fixing buttons, and a sewing structure on the housing for sewing buttons onto fabric.

[0004] Since some garments may involve multiple different types of buttons, and different types of buttons require different fixing fixtures to fix them, multiple button attaching machines are needed, resulting in a large space occupation for the button attaching machines and a high cost for multiple button attaching machines. Summary of the Invention

[0005] In order to improve the difficulty of attaching buttons of different models by button attaching machines, this application provides a button attaching machine.

[0006] This application provides a button-attaching machine, which adopts the following technical solution: A button-attaching machine includes a housing, a drive mechanism on the housing, a mounting block on the drive mechanism, a rotating structure on the housing, two rotating bars on the rotating structure located on opposite sides of the mounting block, a fixing fixture on the rotating bar, a fixing component on the rotating bar for restricting the movement of the fixing fixture, a locking structure on the mounting block for locking the fixing fixture, and an unlocking structure on the rotating bar for driving the locking structure to unlock.

[0007] By adopting the above technical solution, the rotating structure drives the rotating bar to rotate, allowing the rotating bar to move to the mounting block. At this time, the unlocking structure releases the locking of the fixing fixture, and the fixing component allows the rotating bar to drive the fixing fixture to move. Then, the rotating structure drives another rotating bar to move, allowing the other rotating bar to move to the mounting block. At this time, the locking structure locks the fixing fixture, allowing the fixing fixture to move from the other rotating bar to the mounting block, thereby realizing the replacement of the fixing fixture. Since different fixing fixtures can be adapted to different buttons, the workers do not need to manually replace them, and there is no need to set up two button attaching machines, allowing one button attaching machine to meet the replacement of different types of buttons.

[0008] Optionally, the fixing component includes a fixing magnet for attracting and fixing the fixture.

[0009] By adopting the above technical solution, the fixture is fixed by using a fixed magnet to attract it, so that the fixture can be detached from the mounting block along with the rotating bar, reducing the possibility of the fixture detaching from the rotating bar, so that the rotating bar can stably drive the fixture to move during the rotation.

[0010] Optionally, the locking structure includes a locking plate and a locking elastic element. The locking elastic element is disposed on the housing, and the locking plate is disposed on the locking elastic element. The locking elastic element drives the locking plate to abut against the side of the fixing fixture away from the mounting block.

[0011] By adopting the above technical solution, a locking elastic element is set on the housing, which drives the locking plate to move, so that the locking plate can abut against the side of the fixing fixture away from the mounting block, so that the mounting block and the locking plate can clamp the fixing fixture, allowing the fixing fixture to be stably located on the mounting block, and allowing the fixing fixture to be detached from the rotating bar; and the locking plate can restrict the movement of the fixing fixture on the mounting block, so as to facilitate the installation of the button by the fixing fixture.

[0012] Optionally, the mounting block is provided with a limiting elastic element, and the limiting elastic element is provided with a limiting block. The limiting elastic element drives the limiting block to be located between the locking plate and the mounting block. The height of the limiting block is greater than the height of the fixing fixture. The limiting block has a limiting inclined surface, which is located on the rotation path of the fixing fixture. When the fixing fixture is inserted between the locking plate and the mounting block, the fixing fixture drives the limiting block to move through the limiting inclined surface, and the limiting block disengages from the locking plate and the mounting block.

[0013] By adopting the above technical solution, when the rotating bar drives the fixed fixture to rotate, the limiting inclined surface is located on the rotation path of the fixed fixture, allowing the fixed fixture to push the limiting block to move. In addition, the height of the limiting block is greater than the height of the fixed fixture, and the limiting block is located between the locking plate and the mounting block, so that the locking plate can fall smoothly after the limiting block moves, realizing the locking plate abutting against the fixed fixture. This ensures that the contact area between the locking plate and the fixed fixture is the same, allowing the locking plate to fix the fixed fixture more stably. Compared to the fixed fixture pushing the locking plate towards the locking elastic element during the movement, where the locking plate always clamps the fixed fixture, making it difficult for the fixed fixture to move to the appropriate position, in this application, since the fixed fixture pushes the limiting block, the locking plate abuts against the limiting block instead of the fixed fixture. This allows the fixed fixture to move smoothly to the appropriate position before pushing the limiting block away from between the locking plate and the mounting block, meaning the locking plate can clamp the fixed fixture.

[0014] Optionally, the unlocking structure includes an unlocking bar disposed on a rotating bar. Locking inclined surfaces are formed on the surfaces of opposite sides of the locking plate. The distance between the two locking inclined surfaces gradually increases along the direction from the mounting block to the locking plate. The moving path of the locking inclined surface intersects the rotating path of the unlocking bar. When the unlocking bar abuts against the locking inclined surface, the locking plate moves away from the mounting block. The fixing component is used to lock the fixing fixture.

[0015] By adopting the above technical solution, the rotating structure drives the rotating bar to continue rotating. Since the moving path of the locking inclined surface and the rotating path of the unlocking bar intersect, the unlocking bar can drive the locking plate to move through the locking inclined surface, allowing the locking plate to move smoothly in the direction of the locking elastic element. That is, the locking plate does not abut against the fixed fixture. At this time, the fixing component can lock the fixed fixture. As the rotating bar resets, the fixed fixture can move from the mounting block to the rotating bar, realizing the disassembly of the fixed fixture in the mounting block.

[0016] Optionally, the housing is provided with a baffle; when the fixed fixture is located on the rotating bar, the baffle is located on the rotation path of the fixed fixture, and the baffle drives the fixed fixture to reset.

[0017] By adopting the above technical solution, when the rotating structure drives the rotating bar to rotate, since the baffle is located on the rotation path of the fixed fixture, the baffle can smoothly drive the fixed fixture to rotate, so that the baffle can drive the fixed fixture to reset, so that the fixed fixture can be installed on the mounting block next time.

[0018] Optionally, the rotating bar has a receiving groove, the receiving groove has a receiving spring, the receiving spring has a receiving block, the receiving spring drives the receiving block to protrude out of the receiving groove, and when the receiving block protrudes out of the receiving groove, the receiving block is located on the side of the fixed fixture close to another rotating bar.

[0019] By adopting the above technical solution, the receiving block is protruding from the receiving groove by the receiving spring. The receiving block is located on the side of the fixed fixture close to another rotating bar, so that the receiving block can restrict the fixed fixture from detaching from one end of the rotating bar, allowing the rotating bar to stably drive the fixed fixture to rotate. When the fixed fixture is fixed on the mounting block, the fixed fixture can push the receiving block to move into the receiving groove. At this time, the receiving block does not restrict the movement of the fixed fixture, so that the fixed fixture can detach from the rotating bar.

[0020] Optionally, the fixing fixture is provided with a positioning block, which abuts against the rotating bar; when both ends of the fixing fixture abut against the mounting block and the rotating bar respectively, the positioning block is located between the mounting block and the rotating bar.

[0021] By adopting the above technical solution, the positioning block is located between the mounting block and the rotating bar, which can fix the installation position of the fixed fixture. This reduces the problem of the fixed fixture being difficult to position accurately due to the small range of movement on the rotating bar caused by its rotation. At the same time, when the positioning block abuts against the rotating bar, the staff can know that the fixed fixture is installed in place, without the need for subsequent staff to check the fixed fixture again.

[0022] In summary, this application includes at least one of the following beneficial technical effects: 1. The rotating structure drives the rotating bar to rotate, moving it to the mounting block. At this point, the unlocking structure releases the locking of the fixture, and the fixing component allows the rotating bar to move the fixture. Then, the rotating structure drives another rotating bar to move to the mounting block, where the locking structure locks the fixture, allowing it to move from the other rotating bar to the mounting block. This enables the replacement of the fixture. Since different fixtures can accommodate different buttons, manual replacement is not required, and two button-attaching machines are no longer needed. One button-attaching machine can handle the replacement of different button models.

[0023] 2. When the rotating bar drives the fixed fixture to rotate, the limiting inclined surface is located on the rotation path of the fixed fixture, allowing the fixed fixture to push the limiting block to move. Furthermore, the height of the limiting block is greater than the height of the fixed fixture, and the limiting block is located between the locking plate and the mounting block. This allows the locking plate to fall smoothly after the limiting block moves, achieving contact between the locking plate and the fixed fixture. This ensures that the contact area between the locking plate and the fixed fixture is the same, allowing the locking plate to more stably fix the fixed fixture. In contrast, when the fixed fixture pushes the locking plate towards the locking elastic element during movement, the locking plate always clamps the fixed fixture, making it difficult for the fixed fixture to move to the appropriate position. In this application, because the fixed fixture pushes the limiting block, the locking plate abuts against the limiting block instead of the fixed fixture. This allows the fixed fixture to move smoothly to the appropriate position before pushing the limiting block away from between the locking plate and the mounting block, meaning the locking plate can clamp the fixed fixture. Attached Figure Description

[0024] Figure 1 This is a structural schematic diagram of an embodiment of this application; Figure 2 This is a schematic diagram highlighting the drive mechanism in the embodiments of this application; Figure 3 This is a schematic diagram highlighting the rotating bar in an embodiment of this application; Figure 4 This is an exploded view of the fixed tooling in the embodiments of this application; Figure 5This is a schematic diagram of the structure of the limiting block highlighted in the embodiment of this application.

[0025] Reference numerals: 1. Housing; 11. Drive mechanism; 12. Mounting block; 13. Baffle; 2. Rotating structure; 21. Rotating motor; 22. Rotating gear; 23. Rotating bar; 24. Fixture; 241. Positioning block; 25. Fixing component; 251. Receiving groove; 26. Receiving groove; 261. Receiving spring; 262. Receiving block; 3. Locking structure; 31. Support frame; 32. Locking plate; 33. Locking elastic element; 34. Support plate; 341. Limiting elastic element; 342. Limiting block; 343. Limiting inclined surface; 4. Unlocking structure; 41. Unlocking bar; 42. Locking groove; 43. Locking inclined surface. Detailed Implementation

[0026] The following is in conjunction with the appendix Figures 1-5 This application will be described in further detail.

[0027] This embodiment discloses a button-attaching machine. (Refer to...) Figure 1 and Figure 2 A button-attaching machine includes a housing 1, a drive mechanism 11 on the housing 1, and an mounting block 12 fixedly connected to the drive mechanism 11. The drive mechanism 11 is used to drive the mounting block 12 to move in the vertical direction.

[0028] Reference Figure 2 The housing 1 is provided with a rotating structure 2, which includes a rotating motor 21 and multiple rotating gears 22. The rotating motor 21 is fixedly connected to the housing 1, and the rotating gears 22 are rotatably connected to the housing 1. The drive shaft of the rotating motor 21 is meshed with the rotating gears 22, that is, the rotating motor 21 can drive the multiple rotating gears 22 to rotate.

[0029] Reference Figure 2 and Figure 3 Two rotating bars 23 are rotatably connected to the housing 1. The two rotating bars 23 are respectively fixedly connected to different rotating gears 22, and the two rotating bars 23 are located on opposite sides of the mounting block 12. When the rotating motor 21 is started, the rotating motor 21 can drive the two rotating bars 23 to rotate in the same direction through the rotating gears 22.

[0030] Reference Figure 3 and Figure 4 The rotating bar 23 is equipped with a fixing fixture 24 for fixing the button. The rotating bar 23 is also equipped with a fixing component 25 for fixing the fixing fixture 24. The fixing component 25 includes a fixing magnet that extends along the rotation direction of the rotating bar 23 and is used to attract the fixing fixture 24. A receiving groove 251 is formed on the surface of the rotating bar 23, and the fixing magnet is fixedly connected within the receiving groove 251.

[0031] Reference Figure 4 A positioning block 241 is fixedly connected to the surface of the fixed fixture 24, and the positioning block 241 abuts against the side of the rotating bar 23. The positioning block 241 can be located between the mounting block 12 and the rotating bar 23, and the opposite sides of the positioning block 241 can abut against the mounting block 12 and the rotating bar 23 respectively, so as to realize the positioning of the fixed fixture 24 at the mounting block 12 and the rotating bar 23.

[0032] Reference Figure 4 A receiving groove 26 is formed on the surface of the rotating bar 23. A receiving spring 261 is fixedly connected to the bottom wall of the receiving groove 26. A receiving block 262 is fixedly connected to the other end of the receiving spring 261. The end face of the receiving block 262 away from the receiving spring 261 is an arc surface. The receiving spring 261 drives the receiving block 262 to protrude out of the receiving groove 26. At this time, the receiving block 262 is located on the movement path of the fixed fixture 24 moving away from the rotating bar 23 in the direction of the other rotating bar 23. When the rotating bar 23 rotates, the receiving block 262 is used to prevent the fixed fixture 24 from disengaging from the rotating bar 23.

[0033] Reference Figure 4 The mounting block 12 is equipped with a locking structure 3, which is used to fix the fixing fixture 24 to the mounting block 12. The locking structure 3 includes a locking plate 32 and a locking elastic element 33. A support frame 31 is fixedly connected to the mounting block 12, and the support frame 31 is located on the side of the mounting block 12 away from the ground. The locking elastic element 33 includes a locking spring, one end of which is fixedly connected to the support frame 31, and the other end of which is fixedly connected to the locking plate 32. The locking spring drives the locking plate 32 to move toward the mounting block 12, that is, when the locking plate 32 abuts against the mounting block 12, the locking spring is in a compressed state.

[0034] Reference Figure 5 Two support plates 34 are fixedly connected to the surface of the mounting block 12. Limiting elastic elements 341, including limiting springs, are fixedly connected to the support plates 34. One end of the limiting spring is fixedly connected to the support plate 34, and the other end is fixedly connected to a limiting block 342. The limiting spring drives the limiting block 342 to move away from the support plate 34, positioning the limiting block 342 between the locking plate 32 and the mounting block 12. When the limiting block 342 disengages from between the locking plate 32 and the mounting block 12, the limiting spring is compressed. The height of the limiting block 342 is greater than the height of the fixing fixture 24, facilitating the insertion of the fixing fixture 24 between the locking plate 32 and the mounting block 12.

[0035] Reference Figure 5A limiting slope 343 is formed on the surface of the limiting block 342 away from the limiting spring. The limiting slope 343 is located on the insertion path of the fixing fixture 24. The distance between the limiting slope 343 and the support plate 34 gradually increases along the insertion direction of the fixing fixture 24 on the same side. When the fixing fixture 24 abuts against the mounting block 12, the fixing fixture 24 drives the limiting block 342 to move towards the limiting spring through the limiting slope 343, allowing the limiting block 342 to disengage from the locking plate 32 and the mounting block 12.

[0036] Reference Figure 4 and Figure 5 When the fixed fixture 24 moves onto the mounting block 12 and does not abut against the limiting block 342, the limiting block 342 abuts against the locking plate 32. At this time, the locking plate 32 does not abut against the fixed fixture 24 until the fixed fixture 24 pushes the limiting block 342 to move, allowing the limiting block 342 to disengage from the mounting block 12 and the locking plate 32. At this time, the locking spring drives the locking plate 32 to abut against the fixed fixture 24, thereby locking the fixed fixture 24. Then, the rotating structure 2 drives the rotating bar 23 to reset, and the fixed fixture 24 presses against the receiving block 262, thereby separating the fixed fixture 24 and the rotating bar 23.

[0037] Reference Figure 4 and Figure 5 The unlocking structure 4 includes two unlocking bars 41, which are respectively disposed on different rotating bars 23. Locking grooves 42 are formed on the surfaces of opposite sides of the locking plate 32, and locking ramps 43 are formed on the locking grooves 42. The distance between the locking ramps 43 and the mounting block 12 gradually decreases along the direction from one rotating bar 23 to the other. The movement path of the locking ramps 43 intersects with the rotation path of the unlocking bars 41. When the unlocking bars 41 abut against the locking ramps 43, the unlocking bars 41 drive the locking plate 32 to move away from the mounting block 12 via the locking ramps 43, releasing the locking plate 32 from locking the fixing fixture 24. At this time, the rotating bar 23 is in its second rotation state. When the locking plate 32 abuts against the fixing fixture 24, and the fixing fixture 24 abuts against the rotating bar 23, the rotating bar 23 is in its first rotation state.

[0038] Reference Figure 4 and Figure 5The rotating structure 2 drives the rotating bar 23 to rotate, causing the fixed fixture 24 to abut against the rotating bar 23 and the mounting block 12 respectively. At this time, the locking plate 32 locks the fixed fixture 24, realizing the installation of the fixed fixture 24 in the mounting block 12. If it is necessary to unlock the fixed fixture 24, the rotating structure 2 drives the rotating bar 23 to continue rotating, causing the unlocking bar 41 to move the locking plate 32 away from the mounting block 12 through the locking inclined surface 43, realizing the unlocking of the fixed fixture 24. At this time, the fixed magnet attracts the fixed fixture 24, and then the rotating structure 2 drives the rotating bar 23 to reset. The fixed magnet can drive the fixed fixture 24 to move, allowing the fixed fixture 24 to detach from the mounting block 12, realizing the removal of the fixed fixture 24 from the mounting block 12.

[0039] Reference Figure 1 , Figure 4 and Figure 5 Two baffles 13 are fixedly connected to the housing 1, and the baffles 13 are located on the rotation path of the fixed fixture 24. When the rotating structure 2 drives the rotating bar 23 to rotate, the baffles 13 abut against the fixed fixture 24, allowing the fixed fixture 24 to move along the rotating bar 23. The fixed fixture 24 moves towards the other rotating bar 23, realizing the reset of the fixed fixture 24, so that the fixed fixture 24 can be installed on the mounting block 12 next time.

[0040] The implementation principle of a button-attaching machine according to an embodiment of this application is as follows: If the fixed fixture 24 is installed, the operator first drives the rotating structure 2, which in turn drives the rotating bar 23 to rotate. The fixed fixture 24 moves onto the mounting block 12 and the rotating bar 23. The fixed fixture 24 pushes the limiting block 342, allowing the limiting block 342 to disengage from the locking plate 32 and the mounting block 12. This causes the locking spring to drive the locking plate 32 to abut against the fixed fixture 24, thus locking the fixed fixture 24 and the mounting block 12. After that, the rotating structure 2 drives the rotating bar 23 to reset.

[0041] If the fixed fixture 24 is replaced, the operator drives the rotating structure 2, which drives the rotating bar 23 (which does not have the fixed fixture 24) to rotate. The rotating bar 23 rotates from the first rotation state to the second rotation state, that is, the unlocking bar 41 abuts against the locking slope 43, and the locking plate 32 does not abut against the fixed fixture 24. At this time, the fixing magnet attracts the fixed fixture 24, so that the fixed fixture 24 and the rotating bar 23 are fixed to each other. As the rotating structure 2 drives the rotating bar 23 to reset, the rotating bar 23 moves on the mounting block 12. At this time, the limit spring drives the limit block 342 to insert between the locking plate 32 and the mounting block 12. Then the unlocking bar 41 can disengage from the locking slope 43, and the locking plate 32 can smoothly abut against the limit block 342 away from the surface of the mounting block 12. The rotating structure 2 drives the rotating bar 23 to move, so that the other rotating bar 23 can achieve the installation of the fixed fixture 24. As the fixed fixture 24 is replaced, the rotating structure 2 drives the other rotating bar 23 to rotate. When the other rotating bar 23 rotates to the second rotation state, the rotating bar 23 rotates in a direction away from the other rotating bar 23. At this time, the baffle 13 abuts against the fixed fixture 24, realizing the reset of the fixed fixture 24 on the rotating bar 23, so that the rotating bar 23 can install the fixed fixture 24 next time.

[0042] Unless otherwise defined, the technical or scientific terms used in this application shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," "third," and similar terms used in this application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising" or "including" and similar terms mean that the elements or objects preceding "comprising" or "including" encompass the elements or objects listed following "comprising" or "including" and their equivalents, and do not exclude other elements or objects. "Above," "below," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0043] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the design concept of this application should be included within the protection scope of this application.

Claims

1. A button-attaching machine, comprising a housing (1), wherein a drive mechanism (11) is provided on the housing (1), and a mounting block (12) is provided on the drive mechanism (11), characterized in that: The housing (1) is provided with a rotating structure (2), the rotating structure (2) is provided with two rotating bars (23), the rotating bars (23) are respectively located on both sides of the mounting block (12), the rotating bars (23) are provided with a fixing fixture (24), the rotating bars (23) are provided with a fixing component (25) for restricting the movement of the fixing fixture (24), the mounting block (12) is provided with a locking structure (3) for locking the fixing fixture (24), the rotating bars (23) are provided with an unlocking structure (4), the unlocking structure (4) is used to drive the locking structure (3) to unlock; The locking structure (3) includes a locking plate (32) and a locking elastic element (33). The locking elastic element (33) is disposed on the housing (1), and the locking plate (32) is disposed on the locking elastic element (33). The locking elastic element (33) drives the locking plate (32) to abut against the side of the fixing fixture (24) away from the mounting block (12). The mounting block (12) is provided with a limiting elastic element (341), and the limiting elastic element (341) is provided with a limiting block (342). The limiting elastic element (341) drives the limiting block (342) to be located between the locking plate (32) and the mounting block (12). The height of the limiting block (342) is greater than the height of the fixing fixture (24). The limiting block (342) is provided with a limiting inclined surface (343), and the limiting inclined surface (343) is located on the rotation path of the fixing fixture (24). When the fixing fixture (24) is inserted between the locking plate (32) and the mounting block (12), the fixing fixture (24) drives the limiting block (342) to move through the limiting inclined surface (343), and the limiting block (342) disengages from the locking plate (32) and the mounting block (12). The unlocking structure (4) includes an unlocking bar (41) which is disposed on the rotating bar (23). The locking plate (32) has locking inclined surfaces (43) on both sides. The distance between the two locking inclined surfaces (43) gradually increases along the direction from the mounting block (12) to the locking plate (32). The moving path of the locking inclined surface (43) intersects the rotating path of the unlocking bar (41). When the unlocking bar (41) abuts against the locking inclined surface (43), the locking plate (32) moves away from the mounting block (12). The fixing component (25) is used to lock the fixing fixture (24).

2. The button-attaching machine according to claim 1, characterized in that: The fixing component (25) includes a fixing magnet for attracting and fixing the fixture (24).

3. A button-attaching machine according to claim 1, characterized in that: The housing (1) is provided with a baffle (13); when the fixed fixture (24) is located on the rotating bar (23), the baffle (13) is located on the rotation path of the fixed fixture (24), and the baffle (13) drives the fixed fixture (24) to reset.

4. A button-attaching machine according to claim 3, characterized in that: The rotating bar (23) is provided with a receiving groove (26), and a receiving spring (261) is provided in the receiving groove (26). A receiving block (262) is provided on the receiving spring (261). The receiving spring (261) drives the receiving block (262) to protrude out of the receiving groove (26). When the receiving block (262) protrudes out of the receiving groove (26), the receiving block (262) is located on the side of the fixed fixture (24) close to the other rotating bar (23).

5. A button-attaching machine according to claim 1, characterized in that: The fixed fixture (24) is provided with a positioning block (241), which abuts against the rotating bar (23). When the two ends of the fixed fixture (24) abut against the mounting block (12) and the rotating bar (23) respectively, the positioning block (241) is located between the mounting block (12) and the rotating bar (23).

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