Self-centering knurling device

Abstract

The utility model provides a self-centering knurling device which comprises a fixing frame and a clamping assembly, and a machining channel is formed in the fixing frame; the clamping assembly comprises knurling clamps and a driving part, the multiple knurling clamps are arranged around the machining channel at equal intervals, each knurling clamp comprises a clamping support and a knurling head arranged at one end of the clamping support in a sliding mode, the clamping supports are all arranged on the fixing frame, and one end of each knurling head is located in the machining channel; the driving piece is connected to one end of one clamping support and used for driving the knurling head on the clamping support to slide. The knurling device can prevent the workpiece from jumping during knurling, so that the knurling quality is improved.

Description

Technical Field

[0001] The present application relates to the technical field of mechanical processing, and in particular to a self-centering knurling device. Background Art

[0002] The knurling machine is a device used for surface processing of metal or plastic parts. Its main purpose is to form specific textures or patterns on the surface of the workpiece to increase friction, improve aesthetics or facilitate positioning and fixation during subsequent assembly.

[0003] The knurling machine is generally composed of a knurling device, a driving mechanism and a guide system. The knurling device is usually fixed on a lathe, and includes a knurling head and a clamping device. The knurling head is the core component of the knurling device, and is generally composed of one or more carbide tools with specific shapes (such as straight lines, mesh lines, twill lines, etc.). Depending on different processing requirements, the knurling head can be a single tool or a composite structure. The clamping device is used to fix the knurling. The guide system ensures that the knurling head moves accurately along the predetermined path, and usually includes a guide rail and a corresponding positioning device.

[0004] When knurling shaft parts, the workpiece is clamped on a lathe by a knurling device, and the shaft is driven to rotate by a driving mechanism on the lathe, and the knurling device presses out patterns on the circumference of the shaft.

[0005] During the knurling process, it is necessary to avoid the vibration of the shaft to be knurled as much as possible; if the shaft vibrates during the processing, the knurling pattern will be uneven in depth, affecting the appearance and function of the final product. Utility Model Content

[0006] In order to prevent the workpiece from jumping during knurling and improve the quality of knurling, the present application provides a self-centering knurling device.

[0007] The present application provides a self-centering knurling device, which adopts the following technical solution:

[0008] Self-centering knurling device, including:

[0009] A fixed frame, wherein a processing channel is provided on the fixed frame;

[0010] A clamping assembly, the clamping assembly comprising a knurling fixture and a driving member, a plurality of knurling fixtures are arranged at equal intervals around the processing channel, the knurling fixture comprises a clamping support and a knurling head slidably arranged at one end of the clamping support, the clamping supports are all arranged on the fixing frame, and one end of each knurling head is located in the processing channel;

[0011] The driving member is connected to one end of the clamping support and is used to drive the knurling head on the clamping support to slide.

[0012] By adopting the above technical solution, a plurality of knurling fixtures can be equally spaced, enabling uniform clamping force on the workpiece. The driving member drives the movement of the knurling head in one of the knurling fixtures, and adjusts to a reasonable clamping pressure during processing to keep the clamping pressure stable; reduces shaft runout, and ensures the uniformity of the knurled texture and the processing quality.

[0013] Optionally, the clamping support includes a support rod and a mounting cylinder sleeved outside the support rod. The knurling head is arranged at one end of the support rod close to the processing channel, and the end of the mounting cylinder away from the processing channel is closed.

[0014] The closed end of the mounting cylinder is provided with a driving and adjusting member for driving the support rod to move towards the direction close to the processing channel.

[0015] By adopting the above technical solution, the knurling head is slidably connected to the mounting cylinder through the support rod. The driving and adjusting member can be used to drive the sliding of the support rod to adjust the position of the knurling head, so as to adapt to workpieces with different diameters and improve the clamping stability and the accuracy of knurling.

[0016] Optionally, the driving and adjusting member includes a fine-tuning screw. One end of the fine-tuning screw penetrates into the mounting cylinder and is threadedly connected to the mounting cylinder.

[0017] By adopting the above technical solution, by rotating the fine-tuning screw, the support rod can be pushed to slide, so as to accurately adjust the position of the knurling head and realize the stable clamping of workpieces with different diameters.

[0018] Optionally, a force-applying rod section is arranged at one end of the fine-tuning screw away from the knurling head, and a fitting plane is arranged on the circumferential side of the force-applying rod section.

[0019] By adopting the above technical solution, a fitting plane is arranged on the circumferential side of the force-applying rod section, which is convenient for the operator to rotate the fine-tuning screw to achieve rapid adjustment.

[0020] Optionally, a limiting flat key is arranged on the outer side wall of the support rod, and a guiding groove for the limiting flat key to slide is arranged on the inner side wall of the mounting cylinder.

[0021] By adopting the above technical solution, through the cooperation of the limiting flat key and the guiding groove, the circumferential rotation of the support rod in the mounting cylinder is restricted to ensure the stable sliding of the support rod in the mounting cylinder, and further ensure the stable knurling operation of the knurling head.

[0022] Optionally, the clamping support is slidably arranged on the fixed frame, and a locking member for locking the fixed frame is arranged on the fixed frame.

[0023] By adopting the above technical solution, the clamping support is slidably arranged on the fixed frame, and the clamping support is slid in the direction of approaching or departing from the processing channel, so as to greatly adjust the distance between the knurling head and the center of the processing channel, and thus greatly adjust the clamping range of the clamping assembly; after adjusting to a proper position, the clamping support can be locked by using a locking member, so as to further improve the applicability.

[0024] Optionally, a plurality of groups of adjusting hole groups are formed on the fixed frame, and each clamping support is correspondingly provided with the adjusting hole group;

[0025] The processing channel is arranged as a circular channel, the adjusting hole group includes a plurality of adjusting holes arranged at intervals along the diameter of the processing channel, and a plurality of matching holes corresponding to the adjusting holes one by one are formed on the outer side wall of the mounting cylinder;

[0026] The locking member includes a locking bolt, and one end of the locking bolt passes through the adjusting hole and is threadedly connected into the matching hole.

[0027] By adopting the above technical solution, one end of the locking bolt passes through the adjusting hole and is threadedly connected into the matching hole, which is convenient for adjusting the position of the clamping support according to the diameter of the workpiece. By screwing the locking bolt through different adjusting holes into the corresponding matching holes of the clamping support, the clamping support is fixed to a proper position.

[0028] Optionally, the locking member further includes a locking bar and a plug pin fixed to one side of the locking bar, the locking bolt is arranged on the locking bar, and the plug pins are arranged on both sides of the locking bolt;

[0029] A pin hole group for the plug pin to be inserted is formed on the fixed frame, the pin hole group is arranged corresponding to the adjusting holes in the adjusting hole group one by one, and a plug hole for the plug pin to be inserted is formed on the outer side wall of the mounting cylinder.

[0030] By adopting the above technical solution, through the cooperation of the plug pin and the pin hole group, the stability of the clamping support after locking is further enhanced, and the knurling fixture is prevented from shifting during the knurling process.

[0031] Optionally, a limiting edge is arranged at one end of the guiding groove close to the processing channel, and the limiting edge is used for abutting against the limiting flat key.

[0032] By adopting the above technical solution, the limiting edge is used for abutting against the flat key, so as to prevent the supporting rod from sliding excessively and disengaging from the mounting cylinder, and ensure that the knurling head does not deviate from the predetermined position.

[0033] Optionally, the fixing bracket (1) includes a connecting plate (12) and annular fixing plates (11) disposed on both sides of the connecting plate (12). The connecting plate (12) includes a first support plate (121) and a second support plate (122). The first support plate (121) is fixedly connected to the annular fixing plate (11).

[0034] One end of the first support plate (121) is provided with a splicing block (1211), and one end of the second support plate (122) is provided with a splicing groove (1221) for the splicing block (1211) to be snapped into. The splicing block (1211) is rotatably connected in the splicing groove (1221). A sliding guide member (8) is provided at the end of the first support plate (121) away from the second support plate (122), and a fixing member (7) is provided at the end of the second support plate (122) away from the first support plate (121).

[0035] By adopting the above technical solution, during use, the fixing bracket needs to be connected to the lathe. Among them, one end of the first support plate is slidably connected to the lathe through the sliding guide member, and one end of the second support plate is fixed to the lathe through the fixing member. The splicing convex block is rotatably connected in the splicing groove, realizing the movable connection of the first support plate on the lathe. During the processing, under the action of the first support plate, the whole fixing bracket can float in the vertical direction along with the first support plate, buffering and releasing the radial force generated during the knurling process, so as to reduce the damage caused by the knurling process to the lathe and the fixing bracket.

[0036] In summary, the present application includes at least one of the following beneficial effects:

[0037] 1. The present application uses a plurality of knurling jigs arranged at equal intervals to jointly clamp the workpiece, realizing the centering clamping of shaft workpieces with different diameters, reducing the shaft runout, and thus ensuring the uniformity of the knurling texture and the stability of the processing quality;

[0038] 2. Through the setting of the driving member in the present application, the pressure of one knurling jig is adjusted. Taking the other knurling jigs as a reference, the plurality of knurling jigs cooperate with each other, making the clamping pressure stable and effectively reducing the runout of the workpiece during knurling;

[0039] 3. In the present application, by setting the fine adjustment screw, the position of the knurling head can be accurately adjusted to adapt to workpieces with different diameters;

[0040] 4. Through the setting of the fitting plane on the force application rod section of the fine adjustment screw in the present application, it is convenient for the operator to quickly and accurately adjust the position of the knurling head, improving the convenience and efficiency of the operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is the overall structural schematic diagram of the self-centering knurling device in Embodiment 1 of the present application;

[0042] Figure 2 It is a schematic cross-sectional structure diagram of the self-centering knurling device according to Embodiment 1 of the present application;

[0043] Figure 3 It is a schematic exploded structure diagram of the self-centering knurling device according to Embodiment 1 of the present application;

[0044] Figure 4 It is a schematic cross-sectional structure diagram of the knurling fixture according to Embodiment 2 of the present application;

[0045] Figure 5 It is a schematic exploded structure diagram of the self-centering knurling device according to Embodiment 2 of the present application;

[0046] Explanation of reference numerals: 1, fixed frame; 11, annular fixing plate; 12, connecting plate; 121, first support plate; 1211, splicing block; 122, second support plate; 1221, splicing groove; 13, processing channel; 14, adjusting hole; 15, pin hole; 2, knurling fixture; 21, clamping support; 211, mounting cylinder; 2111, mating hole; 2112, insertion hole; 2113, guiding groove; 2114, limiting edge; 212, support rod; 22, knurling head; 3, driving member; 4, fine-tuning screw; 41, force-applying rod section; 411, fitting plane; 5, limiting flat key; 6, locking member; 61, locking bolt; 62, locking bar; 63, insertion pin; 7, fixing member; 8, sliding guiding member; 9, pin shaft. Detailed implementation manners

[0047] The following will Figures 1-5 make a further detailed description of the present application.

[0048] Embodiment 1:

[0049] The self-centering knurling device provided by the embodiment of the present application, as Figure 1 and Figure 2 shown, includes a fixed frame 1 and a clamping assembly. The fixed frame 1 includes two relatively arranged annular fixing plates 11, and a connecting plate 12 fixed between the two annular fixing plates 11. The connecting plate 12 is located at the bottom of the annular fixing plates 11. The two annular fixing plates 11 are specifically arranged in a circular ring shape, and a processing channel 13 is formed between the inner circles of the two annular fixing plates 11.

[0050] As Figure 1 and Figure 2As shown, the connecting plate 12 includes a first support plate 121 and a second support plate 122. The two sides of the first support plate 121 are respectively welded and fixed to two annular fixing plates 11. One end of the first support plate 121 is integrally formed with a plurality of splicing blocks 1211. A plurality of splicing grooves 1221 are formed at one end of the second support plate 122 close to the first support plate 121, and the splicing blocks 1211 and the splicing grooves 1221 are arranged in one-to-one correspondence. The splicing blocks 1211 are snapped into the splicing grooves 1221. A pin shaft 9 is inserted through the side wall of the second support plate 122, and the pin shaft 9 passes through all the splicing blocks 1211 to realize the hinge connection between the first support plate 121 and the second support plate 122. As Figure 1 and Figure 3 shown, a sliding guide 8 is inserted through one end of the first support plate 121 away from the second support plate 122. The sliding guide 8 is specifically set as a guide bolt. During use, one end of the guide bolt is inserted through the first support plate 121 and then threadedly connected to a lathe (not shown in the figure), and the bolt head of the guide bolt is slidably connected to the first support plate 121 to provide guidance for the movement of the first support plate 121. A fixing member 7 is inserted through one end of the second support plate 122 away from the first support plate 121. The fixing member 7 is specifically set as a fixing bolt. During use, the second support plate 122 needs to be fixedly connected to a lathe (not shown in the figure) through the fixing bolt. During the processing, under the action of the first support plate 121, the whole fixing frame 1 can float in the vertical direction along with the first support plate 121 to buffer and release the radial force generated during the knurling process, so as to reduce the damage caused by the knurling process to the lathe and the fixing frame 1.

[0051] The first support plate 121 and the second support plate 122 are cut from a whole piece of plate by wire cutting. The cutting gap ranges from 18 to 22 wires; in this embodiment, the cutting gap is specifically 20 wires.

[0052] In other embodiments, one end of the guide bolt can also be inserted through the first support plate 121 and then threadedly connected to the lathe, so that the bolt head of the guide bolt keeps a certain distance from the first support plate 121 to realize the sliding connection of the first support plate 121 on the lathe.

[0053] As Figure 3 shown, the clamping assembly includes a knurling fixture 2 and a driving member 3. A plurality of knurling fixtures 2 are arranged at equal intervals around the axis of the processing channel 13. Each knurling fixture 2 is composed of a clamping support 21 and a knurling head 22 slidably arranged at one end of the clamping support 21. Each clamping support 21 is located between the two annular fixing plates 11, and each knurling head 22 is located in the processing channel 13. The clamping support 21 includes a support rod 212 and a mounting cylinder 211. One end of the mounting cylinder 211 away from the knurling head 22 is closed. And the mounting cylinder 211 is sleeved outside the support rod 212.

[0054] As Figure 3As shown, the knurled head 22 is fixed to one end of the support rod 212 close to the processing channel 13. By sliding the support rod 212, the distance between the knurled head 22 and the axis of the processing channel 13 can be adjusted to control the clamping range. A driving adjustment member is specially provided on the mounting cylinder 211, which can drive the support rod 212 to move slightly in the direction close to the processing channel 13. The driving adjustment member includes a fine adjustment screw 4. One end of the fine adjustment screw 4 passes through the mounting cylinder 211 along the closed end of the mounting cylinder 211 and is threadedly connected to the mounting cylinder 211. The position of the knurled head 22 can be precisely adjusted by rotating the fine adjustment screw 4, so as to meet the clamping requirements of workpieces with different diameters.

[0055] As Figure 1 shown, for the convenience of operation, a force application rod section 41 is integrally formed at one end of the fine adjustment screw 4 away from the knurled head 22. A fitting plane 411 is machined on the circumferential side of the force application rod section 41. In this embodiment, four fitting planes 411 are machined at equal intervals around the circumference of the fine adjustment screw 4. The operator can rotate the fine adjustment screw 4 using a tool or manually to achieve fast and precise adjustment.

[0056] As Figure 3 shown, a keyway is formed on the outer side wall of the support rod 212, and a limit flat key 5 is installed in the keyway by clearance fit. At the same time, a guide groove 2113 for the limit flat key 5 to slide is formed on the inner side wall of the mounting cylinder 211. The setting of the limit flat key 5 and the guide groove 2113 ensures the stability of the support rod 212 during the sliding process and also limits the rotational freedom of the clamping support 21, thus ensuring the accuracy and adjustability of the position of the knurled head 22.

[0057] In this embodiment, three knurling jigs 2 are specifically provided, and the adjacent two knurling jigs 2 are arranged at an interval of 120°. Only two of the knurling jigs 2 are provided with the fine adjustment screw 4.

[0058] As Figure 1 shown, the driving member 3 is fixedly connected to one end of the clamping support 21 without the fine adjustment screw 4 by bolts. In this embodiment, the driving member 3 is specifically set as a hydraulic cylinder. One end of the telescopic rod of the driving member 3 passes through the mounting cylinder 211 and is fixedly connected to the support rod 212. Starting the driving member 3 can drive the knurled head 22 on the clamping support 21 to slide, thereby realizing fine adjustment of the position of the knurled head 22. Selecting a hydraulic cylinder drive can provide precise positioning and control, and the hydraulic cylinder can generate a greater clamping force than a pneumatic or mechanical system, which helps to prevent the workpiece from moving or deforming during processing. In addition, the hydraulic cylinder can provide smooth and continuous movement, reducing vibration and impact.

[0059] As Figure 1 and Figure 3As shown in the figure, each clamping support 21 is slidably arranged between two annular fixing plates 11, and a locking member 6 is arranged on each annular fixing plate 11. A plurality of groups of adjusting holes 14 are formed in the fixing frame 1, and the groups of adjusting holes 14 are arranged in one-to-one correspondence with the clamping supports 21. The adjusting holes 14 are specifically formed in the annular fixing plates 11. In this embodiment, a group of adjusting holes 14 includes three columns of adjusting holes 14, and each column of adjusting holes 14 includes five adjusting holes 14 arranged at equal intervals in the radial direction of the processing channel 13. A mating hole 2111 corresponding to the adjusting hole 14 is formed on the outer side wall of the mounting cylinder 211. The locking member 6 includes a plurality of locking bolts 61. One end of the locking bolt 61 passes through the adjusting hole 14 and is threadedly connected in the mating hole 2111, so as to firmly lock the clamping support 21 on the fixing frame 1. In this embodiment, one clamping support 21 corresponds to one locking member 6, and one locking member 6 includes a locking bolt 61.

[0060] The implementation principle of this embodiment is as follows: During use, after fixing the first support plate 121 and the second support plate 122 to the lathe through fixing bolts, the workpiece to be processed is inserted into the processing channel 13. By using a plurality of knurling heads 22 arranged at equal intervals to clamp the workpiece to be processed, the centering purpose is achieved. Starting the lathe can drive the workpiece to be processed to rotate for knurling. The shaft runout phenomenon is effectively reduced, thereby ensuring the uniformity of the knurled texture and the processing quality. At the same time, the position of the knurling head 22 is precisely adjusted by using the fine adjustment screw 4; in addition, the clamping range of the clamping assembly is greatly adjusted by the combined action of the locking member 6, the adjusting hole 14 and the mating hole 2111; so that the knurling device can adapt to workpieces of different diameters, further improving its versatility and practicality.

[0061] Embodiment 2:

[0062] As Figure 4 and Figure 5 shown, the difference between this embodiment and Embodiment 1 is that:

[0063] Furthermore, a limiting edge 2114 is integrally formed at one end of the guiding groove 2113 close to the processing channel 13. When the support rod 212 slides in the mounting cylinder 211, the limiting flat key 5 on the support rod 212 can abut against the limiting edge 2114, thereby limiting the maximum sliding distance of the support rod 212 and preventing the support rod 212 from accidentally slipping out of or moving excessively in the mounting cylinder 211.

[0064] As Figure 5As shown in the figure, the locking member 6 includes a locking bar 62 and a plug pin 63 fixed to one side of the locking bar 62. Only one locking bolt 61 is provided in the locking member 6. The screw rod of the screw penetrates through the locking bar 62, and a plug pin 63 is provided on both sides thereof. A set of pin holes into which the plug pin 63 is inserted is formed in the annular fixing plate 11. The set of pin holes includes two pin holes 15 arranged at intervals. In this embodiment, the set of adjustment holes only includes a row of adjustment holes 14, and the row of adjustment holes 14 includes five adjustment holes 14 arranged at equal intervals in the radial direction of the processing channel 13. The set of pin holes and the adjustment holes 14 in the set of adjustment holes are arranged in one-to-one correspondence. At the same time, a plug hole 2112 for inserting the plug pin 63 is also formed in the clamping support 21, and the plug hole 2112 is arranged in one-to-one correspondence with the pin hole 15.

[0065] By moving each clamping support 21, the clamping range of the clamping assembly can be adjusted significantly. After moving the clamping support 21 to a suitable position, after inserting the plug pin 63 in the locking member 6 into the corresponding set of pin holes and then into the plug hole 2112, the locking bolt 61 is passed through the adjustment hole 14 along the locking bar 62 and then threadedly connected to the mating hole 2111. The cooperation between the plug pin 63 and the set of pin holes enhances the stability of the clamping support 21 and the firmness of locking, ensuring that the clamping support 21 does not displace or loosen during the knurling process. Compared with Embodiment 1, while ensuring the locking stability, the locking operation is simplified and the locking efficiency is improved. In this embodiment, locking members are provided on both opposite sides of an installation cylinder 211, and two locking members 6 are connected to one side of the installation cylinder 211 at intervals.

[0066] The above are all the preferred embodiments of this application. The protection scope of this application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.

Claims

1. Self-centering knurling device, characterized in that: include: A fixed frame (1), wherein a processing channel (13) is provided on the fixed frame (1); A clamping assembly, the clamping assembly comprising a knurling fixture (2) and a driving member (3), a plurality of the knurling fixtures (2) being arranged at equal intervals around the processing channel (13), the knurling fixture (2) comprising a clamping support (21) and a knurling head (22) slidably arranged at one end of the clamping support (21), the clamping supports (21) being arranged on the fixing frame (1), and one end of each of the knurling heads being located in the processing channel (13); The driving member (3) is connected to one end of the clamping support (21) and is used to drive the knurled head (22) on the clamping support (21) to slide.

2. The self-centering knurling device according to claim 1, characterized in that: The clamping support (21) comprises a support rod (212) and a mounting tube (211) sleeved outside the support rod (212); the knurled head (22) is arranged at one end of the support rod (212) close to the processing channel (13); and the mounting tube (211) is closed at one end away from the processing channel (13); A driving adjustment member is provided at the closed end of the mounting cylinder (211), and the driving adjustment member is used to drive the support rod (212) to move in a direction close to the processing channel (13).

3. The self-centering knurling device according to claim 2, characterized in that: The drive adjustment member comprises a fine-tuning screw (4), one end of which is inserted into the mounting tube (211) and is threadedly connected to the mounting tube (211).

4. The self-centering knurling device according to claim 3, characterized in that: A force-applying rod section (41) is provided at one end of the fine-tuning screw rod (4) away from the knurled head (22), and a fitting plane (411) is provided on the circumferential side of the force-applying rod section (41).

5. The self-centering knurling device according to claim 2, characterized in that: A limit flat key (5) is provided on the outer side wall of the support rod (212), and a guide groove (2113) for the limit flat key (5) to slide is provided on the inner side wall of the mounting tube (211).

6. The self-centering knurling device according to claim 2, characterized in that: The clamping support (21) is slidably arranged on the fixing frame (1), and the fixing frame (1) is provided with a locking member (6) for locking the fixing frame (1).

7. The self-centering knurling device according to claim 6, characterized in that: The fixing frame (1) is provided with a plurality of adjustment hole groups, and each of the clamping supports (21) is provided with a corresponding adjustment hole group; The processing channel (13) is configured as a circular channel, the adjustment hole group comprises a plurality of adjustment holes (14) arranged at intervals along the diameter of the processing channel (13), and matching holes (2111) corresponding one-to-one to the adjustment holes (14) are provided on the outer side wall of the mounting cylinder (211); The locking member (6) comprises a locking bolt (61), and one end of the locking bolt (61) passes through the adjustment hole (14) and is threadedly connected to the matching hole (2111).

8. The self-centering knurling device according to claim 7, characterized in that: The locking member (6) further comprises a locking strip (62) and a plug pin (63) fixed to one side of the locking strip (62), the locking bolt (61) is passed through the locking strip (62), and the plug pin (63) is provided on both sides of the locking bolt (61); The fixing frame (1) is provided with a pin hole group for the plug pin (63) to be plugged in, the pin hole group is arranged in a one-to-one correspondence with the adjustment holes (14) in the adjustment hole group, and the outer wall of the mounting cylinder (211) is provided with a plug hole (2112) for the plug pin (63) to be plugged in.

9. The self-centering knurling device according to claim 5, characterized in that: A limiting edge (2114) is provided at one end of the guide groove (2113) close to the processing channel (13), and the limiting edge (2114) is used to abut against the limiting flat key (5).

10. The self-centering knurling device according to claim 7, characterized in that: The fixing frame (1) comprises a connecting plate (12) and an annular fixing plate (11) arranged on both sides of the connecting plate (12), the connecting plate (12) comprises a first supporting plate (121) and a second supporting plate (122), and the first supporting plate (121) is fixedly connected to the annular fixing plate (11); A splicing block (1211) is provided at one end of the first support plate (121), a splicing groove (1221) for the splicing block (1211) to be engaged is provided at one end of the second support plate (122), the splicing block (1211) is rotatably connected in the splicing groove (1221), a sliding guide (8) is provided at one end of the first support plate (121) away from the second support plate (122), and a fixing member (7) is provided at one end of the second support plate (122) away from the first support plate (121).

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