Supporting device for steel pipe fitting machining

Abstract

The utility model relates to the field of machining auxiliary equipment, and discloses a steel pipe fitting machining supporting device which comprises a plurality of supporting seats distributed in the axial direction of a steel pipe fitting, inner arc grooves are concavely formed in the tops of the supporting seats, limiting assemblies are arranged in the inner arc grooves, and first cavities are formed in the supporting seats; the limiting assembly comprises two rotating rods which are parallel to the axial direction of the inner arc groove and are rotationally arranged on the supporting seat, arc-shaped supporting blocks arranged on the rotating rods in a sleeving mode and a driving part for driving the two rotating rods to rotate relatively, the two rotating rods are distributed on the two axial sides of the inner arc groove at equal intervals, and the inner arc surfaces of the arc-shaped supporting blocks on the two sides are oppositely arranged; through holes communicated with the first cavity are formed in the supporting seat and correspond to the arc-shaped supporting blocks, top supporting blocks are arranged at the positions, located on the two axial sides of the inner arc groove, of the top of the supporting seat in a lifting mode, the tops of the top supporting blocks are obliquely arranged in cooperation with the inclined face of the delta wing, and a lifting assembly for driving the top supporting blocks to synchronously ascend and descend is further arranged in the supporting seat. The effect of improving the stability of the supporting device is achieved.

Description

Technical Field

[0001] This application relates to the field of auxiliary equipment for machining, and in particular to a support device for machining steel pipe fittings. Background Technology

[0002] In modern industrial systems, steel pipe fittings, as indispensable basic components, are deeply integrated into key fields such as construction, automotive, and aerospace. In the construction industry, they form the stable framework of skyscrapers, bearing enormous vertical and horizontal loads, and are core to ensuring structural safety. In automotive manufacturing, steel pipe fittings are widely used in critical components such as chassis and drive shafts, directly affecting vehicle handling performance and driving safety. The aerospace industry sets near-stringent standards for the precision and quality of steel pipe fittings; their performance directly impacts aircraft power transmission, structural strength, and even flight safety. With the accelerated advancement of industrial automation, various industries are placing unprecedented demands on the processing precision and production efficiency of steel pipe fittings.

[0003] Reference Figure 1 A steel pipe fitting includes a pipe body 01, two triangular wings 02, and several pads 03. The triangular wings 02 are symmetrically distributed on both sides of the pipe body 01 radially, with their length direction parallel to the axial direction of the pipe body 01. The corner edges face the pipe body 01 and are firmly connected to the side wall of the pipe body 01 by welding. The several pads 03 are evenly arranged along the axial direction of the pipe body 01 and welded to the side wall of the pipe body 01. Their length direction is consistent with the distribution direction of the two triangular wings 02, playing a key role in stabilizing the steel pipe fitting during transportation.

[0004] In the processing of this steel pipe fitting, grinding and polishing the triangular wing bevel is a crucial step. However, the simple pad support method commonly used in the industry has significant drawbacks. Because one side of the pipe lacks a planar support structure formed by a pad, when this side is placed on a pad for grinding the triangular wing bevel, the steel pipe fitting is prone to displacement, shaking, or even rolling under processing forces. This not only leads to deviations in dimensional, shape, and positional accuracy of the processed steel pipe fitting, directly affecting product quality, but also may cause impact damage to processing equipment due to the unstable movement of the steel pipe fitting, even leading to serious safety accidents, greatly restricting the improvement of steel pipe fitting processing quality and efficiency. Utility Model Content

[0005] To improve the stability of the support device, this application provides a support device for processing steel pipe fittings.

[0006] The supporting device for processing steel pipe fittings provided in this application adopts the following technical solution:

[0007] A support device for processing steel pipe fittings includes several support seats distributed along the axial direction of the steel pipe fittings. The top of each support seat is recessed with an inner arc groove for inserting a pipe body. A limiting component is provided in the inner arc groove to adapt to the curvature of the outer surface of the pipe body. A first cavity is provided in the support seat to accommodate the limiting component. The limiting component includes two rotating rods rotatably mounted on the support seat parallel to the inner arc groove, an arc-shaped support block sleeved on the rotating rods, and a driving component for driving the two rotating rods to rotate relative to each other. The two rotating rods are equidistantly distributed on both sides of the axial direction of the inner arc groove, and the inner arc surfaces of the arc-shaped support blocks on both sides are arranged opposite to each other. A through hole communicating with the first cavity is provided on the support seat for each arc-shaped support block. Top support blocks are raised and lowered on both sides of the inner arc groove at the top of the support seat. The top of the top support block is inclined to match the inclined surface of the delta wing to support the delta wing. A lifting component is also provided in the support seat to drive multiple top support blocks to rise and fall synchronously.

[0008] By adopting the above technical solution, before grinding the triangular wing of the steel pipe fitting, the pipe body is first inserted into the inner arc groove at the top of several support seats. Then, the driving component in the limiting assembly drives two rotating rods to rotate relative to each other, causing the arc-shaped support blocks sleeved on the rotating rods to move inward and tightly fit against the outer surface of the pipe body, thereby effectively fixing the steel pipe fitting. Based on this, the lifting assembly drives the top support blocks located on both sides of the inner arc groove to rise synchronously. The inclined tops of the top support blocks can precisely support the inclined surface of the triangular wing of the steel pipe fitting, further providing stable support. This solution not only effectively fixes the steel pipe fitting, reducing the possibility of displacement or shaking during processing, but also ensures stable support for the inclined surface of the triangular wing, thereby significantly improving processing accuracy and stability, effectively reducing the risk of equipment damage or safety accidents caused by unstable steel pipe fittings, and greatly improving the quality and efficiency of steel pipe fitting processing.

[0009] Optionally, the driving component includes a gear sleeved on the rotating rod and a brake motor that drives the rotating rod to rotate. The gear is located in the first cavity and the two gears are rotatably meshed. The brake motor is mounted on a support base, and its output shaft is coaxially connected to one of the rotating rods.

[0010] By adopting the above technical solution, the brake motor drives the rotating rod to rotate, which in turn drives the gears to rotate. Due to the meshing transmission between the two gears, the relative rotation of the two rotating rods is achieved. This design allows the arc-shaped support block to adapt to steel pipes of various diameters, improving the stability of clamping and limiting the outer surface of the pipe body, effectively reducing the risk of displacement or rolling of the steel pipe during processing, and significantly improving the stability of the support device. In addition, the precise control capability of the brake motor further enhances the reliability of the adjustment process, ensuring the quality and efficiency of steel pipe processing.

[0011] Optionally, the support base has a second cavity. The lifting assembly includes a support plate that slides and lifts within the second cavity, a vertical rod connecting each top support block to the support plate, and a hydraulic cylinder that drives the support plate to lift. The top of the support base has a receiving groove corresponding to each top support block. The top support block is located in the receiving groove and is lifted and lowered in conjunction with the receiving groove. The vertical rod slides through the support base. The hydraulic cylinder is located below the support plate. The cylinder body of the hydraulic cylinder is disposed on the inner bottom wall of the second cavity. The top end of the piston rod of the hydraulic cylinder is connected to the bottom wall of the support plate.

[0012] By adopting the above technical solution, the hydraulic cylinder pushes the support plate to rise and slide within the second cavity. The support plate, through the vertical rod, drives the top support blocks to rise and fall synchronously within the receiving groove. This allows multiple top support blocks to adjust their height simultaneously, thereby achieving precise support for the delta wing, effectively reducing the risk of displacement, shaking, or rolling of the delta wing during grinding, and significantly improving the stability and processing accuracy of the support device.

[0013] Optionally, an L-shaped connecting plate is connected to two outer side walls of the support base parallel to the axial direction of the inner arc groove. An upward-opening insertion space is formed between the connecting plate and the outer side wall of the support base. A correction rod is inserted into the insertion space on the same side of several support bases. The correction rod is vertically inserted into the insertion space.

[0014] By adopting the above technical solution, multiple support seats can achieve precise synchronous positioning with the help of the correction rod, effectively reducing the risk of overall tilting of the steel pipe fitting caused by the positional deviation of a single support seat. This design significantly enhances the stability of the support device and greatly improves the alignment accuracy when the steel pipe fitting is inserted into the inner arc groove. During subsequent grinding of the triangular wing, the precision of the operation can be improved, thereby effectively improving product quality and reducing processing errors.

[0015] Optionally, the correction rod is provided with scale markings along its length.

[0016] By adopting the above technical solution, the setting of scale markings provides an intuitive length reference when adjusting the position of the correction rod, which makes it easier for operators to accurately control the relative position between each support, thereby improving the installation accuracy and consistency of the entire support device.

[0017] Optionally, rubber pads are provided on the surface of the inner arc groove and the inner arc surface of the arc-shaped support block.

[0018] By adopting the above technical solution, the rubber pad increases the friction between the inner arc groove surface and the inner arc surface of the arc-shaped support block and the pipe body, effectively reducing the risk of slippage or rolling of the steel pipe fittings during processing, thereby improving the stability of the support device. At the same time, the rubber pad also has a certain buffering effect, absorbing vibrations generated during processing to a certain extent and reducing the possibility of damage to the steel pipe fittings and support device.

[0019] Optionally, the bottom of the support base is provided with several omnidirectional positioning wheels.

[0020] By adopting the above technical solution, the universal positioning wheels arranged at the bottom of the support base can flexibly adjust the overall position of the support device, improving the ease of movement of the equipment.

[0021] Optionally, a support plate is detachably mounted on the support base near the top of the inner arc groove. A guide strip is mounted on the side wall of the support base facing the support plate. The guide strip is parallel to the axial direction of the inner arc groove. A guide groove is formed on the side wall of the support plate corresponding to the guide strip. The end of the guide groove extends to the side wall of the support plate. The guide strip and the guide groove are slidably engaged. A handle for easy pulling is provided on the side wall of the support plate adjacent to the guide strip.

[0022] By adopting the above technical solution, when grinding the other side of the triangular wing of the steel pipe fitting is required, the steel pipe fitting is first suspended and flipped using an external lifting device, so that the pad side faces downwards. Before the steel pipe fitting is lowered, the operator can easily slide the support plate along the guide strip using the handle until the support plate completely covers the inner arc groove. The support plate provides a flat and stable support surface for the pad on the steel pipe fitting, and together with the top support block to support and restrict the triangular wing, it can further improve the convenience and stability of the triangular wing grinding process, thereby improving the overall processing quality and efficiency.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. Before grinding the triangular wing of the steel pipe fitting, the pipe body is first inserted into the inner arc groove at the top of several support seats. Then, the driving component in the limiting assembly drives two rotating rods to rotate relative to each other, causing the arc-shaped support blocks sleeved on the rotating rods to move inward and tightly fit against the outer surface of the pipe body, thus effectively fixing the steel pipe fitting. Based on this, the lifting assembly drives the top support blocks located on both sides of the inner arc groove to rise synchronously. The inclined tops of the top support blocks can precisely support the inclined surface of the triangular wing of the steel pipe fitting, further providing stable support. This solution not only effectively fixes the steel pipe fitting, reducing the possibility of displacement or shaking during processing, but also ensures stable support for the inclined surface of the triangular wing, thereby significantly improving processing accuracy and stability, effectively reducing the risk of equipment damage or safety accidents caused by unstable steel pipe fittings, and greatly improving the quality and efficiency of steel pipe fitting processing.

[0025] 2. The brake motor drives the rotating rod to rotate, which in turn drives the gears to rotate. Due to the meshing transmission between the two gears, the two rotating rods rotate relative to each other. This design allows the arc-shaped support block to adapt to steel pipes of various diameters, improving the stability of clamping and limiting the outer surface of the pipe body, effectively reducing the risk of displacement or rolling of the steel pipe during processing, and significantly improving the stability of the support device. Furthermore, the precise control capability of the brake motor further enhances the reliability of the adjustment process, ensuring the quality and efficiency of steel pipe processing.

[0026] 3. The hydraulic cylinder pushes the support plate to rise and slide within the second cavity. The support plate, via the vertical rod, drives the top support blocks to rise and fall synchronously within the receiving groove. This allows multiple top support blocks to adjust their height simultaneously, thereby achieving precise support for the delta wing, effectively reducing the risk of displacement, shaking, or rolling of the delta wing during grinding, and significantly improving the stability and processing accuracy of the support device. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the composition structure of steel pipe fittings in the prior art.

[0028] Figure 2 This is a schematic diagram of the overall structure of Embodiment 1 of this application.

[0029] Figure 3 This is a schematic diagram illustrating the structure of a single support base in Embodiment 1 of this application.

[0030] Figure 4 This is a cross-sectional view illustrating the internal structure of a single support in Embodiment 1 of this application.

[0031] Figure 5 This is a schematic diagram illustrating the connection relationship between the rotating rod, gear, and brake motor in Embodiment 1 of this application.

[0032] Figure 6This is a schematic diagram of the overall structure of Embodiment 2 of this application.

[0033] Figure 7 This is a schematic diagram illustrating the connection relationship between the guide strip and the support plate inside a single support base in Embodiment 2 of this application.

[0034] Explanation of reference numerals in the attached figures:

[0035] 01. Tube body; 02. Triangular wing; 03. Pad; 1. Support base; 11. Inner arc groove; 12. Connecting plate; 13. First cavity; 14. Through hole; 15. Receiving groove; 16. Second cavity; 17. Guide bar; 2. Universal positioning wheel; 3. Controller; 4. Limiting assembly; 41. Rotating rod; 42. Arc-shaped support block; 421. Rubber pad; 43. Drive component; 431. Gear; 432. Brake motor; 5. Top support block; 6. Lifting assembly; 61. Support plate; 62. Vertical rod; 63. Hydraulic cylinder; 7. Correction rod; 71. Scale marking; 8. Support plate; 81. Guide groove; 9. Handle. Detailed Implementation

[0036] The following is in conjunction with the appendix Figures 2-7 This application will be described in further detail.

[0037] This application discloses a support device for processing steel pipe fittings.

[0038] Example 1

[0039] Reference Figure 2 , Figure 3 and Figure 4 A support device for processing steel pipe fittings includes several support seats 1. In this embodiment, three support seats 1 are distributed along the axial direction of the steel pipe fitting. Each support seat 1 has a universal positioning wheel 2 installed at the four corners of its bottom, and a controller 3 is also installed on the side wall of the support seat 1. The top of the support seat 1 is recessed with an inner arc groove 11 for inserting the pipe body 01, and a limiting component 4 is provided in the inner arc groove 11 to match the curvature of the outer surface of the pipe body 01. Top support blocks 5 are raised and lowered on both sides of the inner arc groove 11 at the top of the support seat 1. The top of the top support block 5 is inclined to match the inclined surface of the triangular wing 02 to support the triangular wing 02, and a lifting component 6 is provided in the support seat 1 to drive multiple top support blocks 5 to rise and fall synchronously.

[0040] Reference Figure 2 , Figure 3 and Figure 4Before grinding the triangular wing 02 of the steel pipe fitting, the pipe body 01 of the steel pipe fitting is first inserted into the inner arc groove 11 at the top of several support seats 1, and then the steel pipe fitting is effectively fixed by the limiting component 4. On this basis, the lifting component 6 drives the top support blocks 5 located on both sides of the inner arc groove 11 to rise synchronously. The inclined top of the top support block 5 can accurately support the inclined surface of the triangular wing 02 of the steel pipe fitting, further providing stable support. Then the grinding operation of the inclined surface of the triangular wing 02 of the steel pipe fitting can begin.

[0041] Reference Figure 2 Each support 1 has a connecting plate 12 fixedly installed on the outer side wall of both sides parallel to the axial direction of the steel pipe. The connecting plate 12 is L-shaped and forms an upward-opening insertion space with the outer side wall of the support 1. A correction rod 7 is inserted into the insertion space on the same side of the three support 1. The correction rod 7 has scale markings 71 electroplated on it along its own length direction and is vertically inserted into the insertion space.

[0042] Reference Figure 3 , Figure 4 and Figure 5 The support base 1 has a first cavity 13 for accommodating the limiting component 4. The limiting component 4 includes two rotating rods 41, an arc-shaped support block 42, and a driving component 43. The two rotating rods 41 are rotatably mounted on the support base 1 parallel to the axial direction of the inner arc groove 11 and are equidistantly distributed on both sides of the inner arc groove 11. The arc-shaped support block 42 is fixedly sleeved on the rotating rods 41, and the inner arc surfaces of the two arc-shaped support blocks 42 face each other. The support base 1 has a through hole 14 corresponding to each arc-shaped support block 42, which communicates with the first cavity 13 for the arc-shaped support block 42 to pass through. Rubber pads 421 are fixedly mounted on the surface of the inner arc groove 11 and the inner arc surface of the arc-shaped support block 42.

[0043] Reference Figure 3 , Figure 4 and Figure 5 The drive unit 43 includes a gear 431 and a brake motor 432. The gear 431 is located in the first cavity 13, and one gear is provided for each rotating rod 41. The gear 431 is fixedly sleeved on the end of the rotating rod 41, and the two gears 431 are rotatably meshed. The brake motor 432 is fixedly installed on the outer wall of the support base 1, and its output shaft is coaxially fixedly connected to one of the rotating rods 41.

[0044] Reference Figure 4The top of the support base 1 has a receiving groove 15 corresponding to each top support block 5. The top support block 5 is located in the receiving groove 15 and is vertically engaged with the receiving groove 15. The lifting assembly 6 includes a support plate 61, a vertical rod 62, and a hydraulic cylinder 63. A second cavity 16 is provided inside the support base 1. The support plate 61 is slidably and vertically assembled in the second cavity 16. Two vertical rods 62 are provided for each top support block 5. The two vertical rods 62 are distributed along the length direction of the top support rod and slide through the support base 1, and are fixedly connected to the top support block 5 and the support plate 61. The hydraulic cylinder 63 is located below the support plate 61. Its cylinder body is fixedly set on the inner bottom wall of the second cavity 16, and its piston rod top is fixed on the bottom wall of the support plate 61. The brake motor 432 and the hydraulic cylinder 63 are both electrically connected to the controller 3.

[0045] The implementation principle of the support device for processing steel pipe fittings according to an embodiment of this application is as follows: Before grinding the triangular wing 02 of the steel pipe fitting, the pipe body 01 of the steel pipe fitting is first inserted into the inner arc groove 11 at the top of several support seats 1. By inputting the parameters of the steel pipe fitting pre-set in the controller 3, the brake motor 432 is started to drive the rotating rod 41 to rotate, which in turn drives the gear 431 to rotate. Due to the meshing transmission between the two gears 431, the relative rotation of the two rotating rods 41 is realized, causing the arc-shaped support block 42 sleeved on the rotating rod 41 to move inward and closely fit the outer surface of the pipe body 01, thereby achieving effective fixation of the steel pipe fitting. On this basis, the hydraulic cylinder 63 pushes the support plate 61 to rise and slide in the second cavity 16. The support plate 61 drives the top support block 5 to rise synchronously in the receiving groove 15 through the vertical rod 62. The inclined top of the top support block 5 can accurately support the inclined surface of the triangular wing 02 of the steel pipe fitting, further providing stable support. Then, the grinding operation of the inclined surface of the triangular wing 02 of the steel pipe fitting can begin. It can not only effectively fix steel pipes and reduce the possibility of displacement or shaking during processing, but also ensure that the inclined plane of the delta wing 02 is stably supported, thereby significantly improving processing accuracy and stability.

[0046] Example 2

[0047] Reference Figure 6 and Figure 7 The difference between this embodiment and embodiment 1 is that a support plate 8 is detachably provided on the top of each support base 1 near the inner arc groove 11.

[0048] Reference Figure 6 and Figure 7 A guide strip 17 is fixedly installed on the side wall of the support base 1 facing the support plate 8. The guide strip 17 is arranged parallel to the axial direction of the inner arc groove 11. A guide groove 81 is opened on the side wall of the support plate 8 corresponding to the guide strip 17. The end of the guide groove 81 extends to the side wall of the support plate 8. The support plate 8 slides with the guide strip 17 through the guide groove 81. A handle 9 is fixedly installed on the side wall of the support plate 8 adjacent to the guide strip 17.

[0049] The implementation principle of Example 2 is as follows: When it is necessary to grind the other side of the triangular wing 02 of the steel pipe fitting, the steel pipe fitting is first suspended and flipped using an external lifting device, so that the pad 03 faces downwards. Before the steel pipe fitting is lowered, the operator can easily slide the support plate 8 along the guide strip 17 using the handle 9 until the support plate 8 completely covers the inner arc groove 11. The support plate 8 provides a flat and stable support surface for the pad 03 on the steel pipe fitting, and together with the top support block 5 supporting and restricting the triangular wing 02, the grinding operation on the inclined surface of the triangular wing 02 of the steel pipe fitting can begin. This can further improve the convenience and stability of the grinding process of the triangular wing 02, thereby improving the overall processing quality and efficiency.

[0050] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A support device for steel pipe work processing, characterized by The utility model provides a kind of steel pipe support, including several support seats (1) distributed along the axis of steel pipe, the top of the support seat (1) is recessed with inner arc groove (11), for inserting pipe body (01), limit component (4) is arranged in the inner arc groove (11), for with the arc of the outer surface of pipe body (01) adaptation, first cavity (13) for accommodating limit component (4) is opened in the support seat (1), the limit component (4) includes two rotation shafts (41) being arranged on the support seat (1) in the axial direction parallel to the inner arc groove (11), arc support block (42) being arranged on rotation shaft (41) and drive member (43) for driving two rotation shafts (41) relative rotation, two rotation shafts (41) are equidistantly distributed in the axial direction of the inner arc groove (11), and the inner arc surface of two arc support blocks (42) is oppositely arranged, the support seat (1) is opened with the through hole (14) being communicated with the first cavity (13) on the top of each arc support block (42), the top of the support seat (1) is arranged with top support block (5) in the axial direction of the inner arc groove (11) on both sides, the top of the top support block (5) is arranged with the inclined surface of the triangular wing (02) in the inclined manner, for supporting the triangular wing (02), the support seat (1) is further provided with lifting assembly (6) for driving multiple top support blocks (5) to synchronously lift.

2. The support device for steel pipe work according to claim 1, characterized by The drive member (43) includes gear (431) being arranged on rotation shaft (41) and band brake motor (432) for driving rotation shaft (41) to rotate, the gear (431) is located in the first cavity (13), and the two gears (431) are rotatably engaged, the band brake motor (432) is arranged on the support seat (1), and the output shaft thereof is coaxially connected with one of the rotation shafts (41).

3. The support device for steel pipe processing according to claim 1, characterized in that The support seat (1) is opened with the second cavity (16), the lifting assembly (6) includes lifting plate (61) sliding in the second cavity (16), vertical rod (62) connecting each top support block (5) with the lifting plate (61) and hydraulic cylinder (63) for driving the lifting plate (61) to lift, the top of the support seat (1) is opened with accommodating groove (15) corresponding to each top support block (5), the top support block (5) is located in the accommodating groove (15) and is lifted in cooperation with the accommodating groove (15), the vertical rod (62) is slidably arranged through the support seat (1), the hydraulic cylinder (63) is located below the lifting plate (61), the cylinder body of the hydraulic cylinder (63) is arranged on the inner bottom wall of the second cavity (16), and the piston rod top end of the hydraulic cylinder (63) is connected to the bottom wall of the lifting plate (61).

4. The support apparatus for steel pipe work according to claim 1, characterized by The support seat (1) is connected with L-shaped connecting plate (12) on the two outer side walls in the axial direction parallel to the inner arc groove (11), the connecting plate (12) and the outer side wall of the support seat (1) form an insertion space with the opening upward, the insertion space on the same side of the plurality of support seats (1) is inserted with the deviation correction rod (7) in common, and the deviation correction rod (7) and the insertion space are vertically inserted in cooperation.

5. A support device for machining a steel pipe according to claim 4, characterized in that The deviation correction rod (7) is provided with scale mark (71) along the length direction of itself.

6. The support apparatus for steel pipe work according to claim 1, wherein The inner arc groove (11) and the inner arc surface of the arc-shaped supporting block (42) are provided with rubber pads (421).

7. The support apparatus for steel pipe work according to claim 1, wherein The bottom of the supporting seat (1) is provided with a plurality of universal positioning wheels (2).

8. The support apparatus for steel pipe work according to claim 1, wherein The top of the supporting seat (1) near the inner arc groove (11) is detachably provided with a supporting plate (8). The side wall of the supporting seat (1) facing the supporting plate (8) is provided with a guide strip (17). The guide strip (17) is parallel to the axial direction of the inner arc groove (11). The side wall of the supporting plate (8) is provided with a guide groove (81) corresponding to the guide strip (17). The end of the guide groove (81) extends to the side wall of the supporting plate (8). The guide strip (17) and the guide groove (81) are in sliding fit. The side wall of the supporting plate (8) adjacent to the guide strip (17) is provided with a handle (9) facilitating pulling.

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