Semi-automatic feeding and positioning workbench for forming machine

Abstract

The utility model relates to the technical field of forming machines, and provides a semi-automatic feeding and positioning workbench for a forming machine, which comprises a bracket, a guide rail arranged on the bracket and a passive feeding trolley connected to the guide rail in a sliding manner, a plurality of supporting rollers are arranged in the length direction of the support at intervals, first positioning rollers are arranged on the portions, located on the two sides of the sectional material, of the upper surface of the driven feeding trolley, and a first adjusting assembly used for adjusting the distance between the first positioning rollers and the sectional material is arranged on the driven trolley. The driven feeding trolley is provided with a clamp used for abutting against the sectional material, the support is provided with a guide structure, and the guide structure is used for driving the clamp to rotate in the direction away from the sectional material so as to relieve abutting against the sectional material. The bending device has the beneficial effect that the possibility of displacement of the sectional material in the height direction in the feeding process is reduced, so that the bending effect of the sectional material is improved.

Description

Technical Field

[0001] The present application relates to the technical field of molding machines, and particularly relates to a semi-automatic feeding and positioning workbench for a molding machine. Background Art

[0002] For profiles that need to be bent, they are first fed through corresponding equipment. The feeding methods in the prior art are usually unwinding feeding or roller-way feeding. For some relatively thick plates, roller-way feeding is usually selected. When feeding some long plates, horizontal displacement may occur during feeding, resulting in a decrease in the subsequent bending effect. Therefore, first positioning rollers are usually provided on the opposite side walls of the profile for positioning. However, when the conveyed plate is long, vertical displacement may occur during feeding, affecting the subsequent bending effect. Therefore, further improvement is needed. Summary of the Utility Model

[0003] In order to reduce the possibility of vertical displacement of the profile during the feeding process and improve the bending effect of the profile, the present application provides a semi-automatic feeding and positioning workbench for a molding machine.

[0004] A semi-automatic feeding and positioning workbench for a molding machine provided by the present application adopts the following technical solutions:

[0005] A semi-automatic feeding and positioning workbench for a molding machine includes a bracket, a guide rail provided on the bracket, and a passive feeding trolley slidably connected to the guide rail. A support roller for supporting the profile is rotatably connected to the upper surface of the bracket. A plurality of the support rollers are arranged at intervals along the length direction of the bracket. First positioning rollers are provided on the upper surface of the passive feeding trolley on both sides of the profile. A first adjusting assembly for adjusting the distance between the first positioning roller and the profile is provided on the passive trolley. A clamp for pressing against the profile is provided on the passive feeding trolley. A guiding structure is provided on the bracket, and the guiding structure is used to drive the clamp to rotate away from the profile to release the pressing on the profile.

[0006] By adopting the above technical solution, a first positioning roller and a first adjusting component are provided to position the profile, and it is also convenient to adjust the position between the two first positioning rollers according to the width of the profile through the first adjusting component to limit the displacement of the profile in the horizontal direction. Among them, after the profile is pressed against the passive feeding trolley by the clamp, when the subsequent forming machine drives the profile to move forward, since the passive feeding trolley is slidably connected to the guide rail and slides along the length direction of the bracket, the passive feeding trolley is driven to move towards the direction close to the forming machine, which can reduce the possibility of the profile having displacement in the height direction during the feeding process and improve the bending effect of the profile. As the feeding increases, the clamping capacity is limited. Therefore, when the passive feeding trolley is driven to the guiding structure, the clamp is driven to rotate away from the profile to release the pressing on the profile, so that the remaining profile can be bent. Then the staff pushes the passive feeding trolley to one end of the bracket away from the forming machine, and then presses the next profile with the clamp, repeating the cycle.

[0007] Preferably, the passive feeding trolley includes a sliding seat slidably connected to the guide rail and a bottom plate arranged on the sliding seat. The lower surface of the bottom plate is provided with a mounting plate for the first adjusting component. The first adjusting component includes a first lead screw rotatably passing through the mounting plate, a first sliding plate slidably connected to the bottom plate, and a first handwheel fixedly connected to the first lead screw. The first lead screw is threadedly passed through the first sliding plate. The lower end of the first positioning roller protrudes with a fixing rod connected to the first sliding plate. The upper surface of the bottom plate is provided with a first through groove through which the fixing rod passes along its width direction.

[0008] By adopting the above technical solution, by rotating the first handwheel, the rotation of the first lead screw is driven, so as to drive the first positioning roller fixed to the sliding plate through the fixing rod to move towards the direction close to the profile to limit the profile in the horizontal direction.

[0009] Preferably, a plurality of the first positioning rollers are arranged at intervals along the length direction of the passive feeding trolley. The length direction of the first sliding plate is parallel to the length direction of the passive feeding trolley. The fixing rods on a plurality of the first positioning rollers on one side are fixedly connected to the same first sliding plate.

[0010] By adopting the above technical solution, by arranging a plurality of first positioning rollers, the positioning effect of the profile in the horizontal direction is improved, and the possibility of deviation is further reduced. In this regard, when connecting a plurality of fixing rods to the same first sliding plate, when the first lead screw is rotated, a plurality of first positioning rollers can be driven to be adjusted along with the sliding of the first sliding plate, so as to reduce the time spent on adjusting the plurality of first positioning rollers.

[0011] Preferably, the length direction of the mounting plate is parallel to the length direction of the bottom plate. Two first lead screws are arranged at intervals along the length direction of one side of the mounting plate. The first adjusting assembly further includes two chain wheels respectively coaxially sleeved on the two first lead screws and a chain wound around the two chain wheels.

[0012] By adopting the above technical solution, by arranging two first lead screws along the length direction of the mounting plate on one side, the sliding stability of the lengthened first sliding plate during sliding can be improved.

[0013] Preferably, the fixture includes a first fixing plate fixedly connected to the upper surface of the passive feeding trolley, a second fixing plate vertically connected to the first fixing plate, a handle hinged to the lower end of the second fixing plate, a mounting rod hinged to the upper end of the second fixing plate, and a pressing head arranged at the end of the mounting rod far from the second fixing plate. The length direction of the handle is parallel to the height direction of the second fixing plate. The mounting rod is hinged with a hinged rod hinged to the handle. The hinge points between the handle and the mounting rod are arranged diagonally. The guiding structure is used to drive the handle to rotate along the hinge point hinged to the second fixing plate.

[0014] By adopting the above technical solution, as the guiding structure drives the handle to rotate along the hinge point hinged to the second fixing plate, the hinged rod, the mounting rod and the pressing head are driven to rotate away from the profile, so as to release the clamping and fixing of the profile.

[0015] Preferably, the guiding structure includes a support rod fixedly connected to the bracket, a cross plate fixedly connected to the support rod extending above the profile, a third fixing plate vertically fixed to the side wall of the cross plate close to the passive feeding trolley, and a guiding seat arranged on the side wall of the third fixing plate close to the support rod. A guiding surface is formed on the surface of the guiding seat far from the third guiding plate. The upper end of the handle abuts against the guiding surface. The distance between the guiding surface and the third fixing plate gradually increases in the direction close to the cross plate.

[0016] By adopting the above technical solution, after the upper end of the handle abuts against the guiding surface, when the fixture is still clamping the profile, at this time, the passive feeding trolley advances along with the profile. During the advancing process, as the handle abuts against the guiding surface, the handle is driven to rotate away from the profile, so as to release the clamping and fixing of the profile by the fixture.

[0017] Preferably, the guiding structure further includes a guiding rod fixedly penetrating through the third fixing plate and a spring coaxially sleeved on the guiding rod. One end of the guiding rod away from the third fixing plate slidably penetrates through the guiding seat. A third through groove is formed through the upper end surface of the guiding seat along its height direction, and the guiding rod is inserted into the third through groove. Two ends of the spring are respectively fixedly connected to the third fixing plate and the guiding seat.

[0018] By adopting the above technical solution, when the guiding surfaces on the handle and the guiding seat are in contact, as the passive feeding trolley moves and rotates, by providing the guiding rod and the spring, the acting force of the handle on the guiding seat can be relieved to a certain extent, and the clamping head can be moved away from the profile relatively slowly.

[0019] Preferably, a second positioning roller is provided at one end of the bracket away from the passive feeding trolley. Two second positioning rollers are provided and are respectively arranged on both sides of the profile. A second adjusting component for adjusting the positions of the two second positioning rollers in the width direction of the bracket is provided on the bracket.

[0020] By adopting the above technical solution, by providing the second positioning rollers, when the clamping of the profile by the fixture is released, the end of the profile in the horizontal direction can be further limited during the subsequent feeding into the molding machine. The second adjusting component is used to adjust the positions of the second positioning rollers in the width direction to adapt to profiles of different widths.

[0021] In summary, the utility model has the following beneficial effects:

[0022] By providing the first positioning rollers and the first adjusting component, the profile can be positioned, and it is also convenient to adjust the positions between the two first positioning rollers according to the width of the profile to limit the displacement of the profile in the horizontal direction. Among them, after the profile is pressed tightly against the passive feeding trolley by the fixture, as the subsequent molding machine drives the profile forward, since the passive feeding trolley is slidably connected to the guide rail and slides along the length direction of the bracket, the passive feeding trolley can be driven to move towards the molding machine, which can reduce the possibility of the profile having displacement in the height direction during the feeding process and improve the bending effect of the profile. As the feeding increases, the clamping capacity is limited. Therefore, when the passive feeding trolley is driven to the guiding structure, the fixture is driven to rotate away from the profile to release the pressing on the profile, so that the remaining profile can be bent. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is the overall structural schematic diagram of the embodiment of the present application;

[0024] Figure 2 is the structural schematic diagram of the latter half of the bracket in the embodiment of the present application;

[0025] Figure 3 It is a schematic structural diagram of the passive feeding trolley in the embodiment of the present application;

[0026] Figure 4 It is a schematic structural diagram of the first adjustment assembly in the embodiment of the present application;

[0027] Figure 5 It is Figure 3 a partial enlarged schematic diagram of part A in;

[0028] Figure 6 It is Figure 2 a partial enlarged schematic diagram of part B in;

[0029] Figure 7 It is Figure 2 a partial enlarged schematic diagram of part C in.

[0030] Description of reference numerals: 1, profile; 2, bracket; 21, support roller; 22, first mounting bracket; 23, second mounting bracket; 3, guide rail; 4, passive feeding trolley; 41, sliding seat; 42, bottom plate; 421, mounting plate; 422, first through groove; 5, first positioning roller; 6, first adjustment assembly; 61, first lead screw; 62, first sliding plate; 63, first hand wheel; 64, sprocket; 65, chain; 7, fixture; 71, first fixing plate; 72, second fixing plate; 73, handle; 74, mounting rod; 741, second through groove; 75, pressing head; 751, mounting screw; 752, nut; 8, guiding structure; 81, support rod; 82, cross plate; 83, third fixing plate; 84, guiding seat; 841, guiding surface; 842, limiting block; 843, third through groove; 85, guiding rod; 86, spring; 9, second positioning roller; 10, second adjustment assembly; 101, second lead screw; 102, second sliding plate; 103, second hand wheel. Detailed implementation manners

[0031] The following will further describe the present application in detail with reference to the attached Figure 1-7 drawings.

[0032] The embodiment of the present application discloses a semi-automatic feeding and positioning workbench for a molding machine.

[0033] Embodiment:

[0034] A semi-automatic feeding and positioning workbench for a molding machine, referring to Figure 1 , Figure 2 , includes a bracket 2, a guide rail 3 arranged on the bracket 2, and a passive feeding trolley 4 slidably connected to the guide rail 3. In this embodiment, the length direction of the guide rail 3 is parallel to the length direction of the bracket 2, and the length of the guide rail 3 is shorter than the length of the bracket 2.

[0035] Among them, a support roller 21 for supporting the profile 1 is rotatably connected to the upper surface of the support 2. A plurality of support rollers 21 are arranged at intervals along the length direction of the support 2. For the installation between the support roller 21 and the support 2, specifically, a first mounting frame 22 is fixedly connected to the upper surface of the support 2. A plurality of first mounting frames 22 are arranged at intervals along the length direction of the support 2, corresponding to the number of support rollers 21. The opposite ends of the support roller 21 are respectively rotatably connected to the two ends of the first mounting frame 22. The first mounting frame 22 is arranged on the upper surface of the support 2 away from the guide rail 3.

[0036] Refer to Figure 2 、 Figure 3 ., among which, the passive feeding trolley 4 includes a sliding seat 41 slidably connected to the guide rail 3 and a bottom plate 42 fixedly connected to the sliding seat 41. First positioning rollers 5 are arranged on the upper surface of the bottom plate 42 on both sides of the profile 1. In this embodiment, a plurality of first positioning rollers 5 are arranged at intervals along the length direction of the bottom plate 42. A first adjusting assembly 6 for adjusting the distance between the first positioning roller 5 and the profile 1 is arranged on the passive feeding trolley 4.

[0037] Refer to Figure 3 、 Figure 4 ., specifically, a mounting plate 421 for the first adjusting assembly 6 is fixedly connected to the lower surface of the bottom plate 42. In this embodiment, the length direction of the mounting plate 421 is parallel to the length direction of the bottom plate 42. There are two mounting plates 421 and the first adjusting assembly 6, and they are respectively arranged on both sides of the bottom plate 42. Among them, the first adjusting assembly 6 specifically includes a first lead screw 61, a first sliding plate 62, a first handwheel 63, a sprocket 64 and a chain 65. Among them, the first lead screw 61 is threadedly penetrated through the first sliding plate 62, the first lead screw 61 is rotatably penetrated through the mounting plate 421. Two first lead screws 61 are arranged at intervals along the length direction of the mounting plate 421. The length direction of the first sliding plate 62 is parallel to the length direction of the mounting plate 421. The first sliding plate 62 slides along the width direction of the bottom plate 42. The first handwheel 63 is coaxially and fixedly connected to the first lead screw 61. In this embodiment, there are two sprockets 64 and they are respectively fixedly sleeved on the two first lead screws 61. The chain 65 is wound around the two sprockets 64. In this embodiment, the first lead screw 61 is a one-way threaded lead screw.

[0038] Among them, a fixing rod rotatably connected to the first sliding plate 62 is fixedly connected to the lower end of the first positioning roller 5. A first through groove 422 through which the fixing rod passes is formed through the upper surface of the bottom plate 42 along its width direction. The fixing rods on a plurality of first positioning rollers 5 on one side are fixedly connected to the same first sliding plate 62.

[0039] Return to Figure 2 、 Figure 3, wherein, a fixture 7 for pressing against the profile 1 is provided on the passive feeding trolley 4. There are two fixtures 7, which are respectively arranged on both sides of the profile 1. A guiding structure 8 is provided on the bracket 2. There are two guiding structures 8, which are symmetrically arranged along the length direction of the bracket 2. The guiding structure 8 is used to drive the fixture 7 to rotate away from the profile 1 to release the pressing against the profile 1.

[0040] Refer to Figure 3 、 Figure 5 , specifically, the fixture 7 includes a first fixing plate 71 fixedly connected to the upper surface of the passive feeding trolley 4, a second fixing plate 72 vertically connected to the first fixing plate 71, a handle 73 hinged to the lower end of the second fixing plate 72, a mounting rod 74 hinged to the upper end of the second fixing plate 72, and a pressing head 75 arranged at one end of the mounting rod 74 away from the second fixing plate 72. In this embodiment, the length direction of the handle 73 is parallel to the height direction of the second fixing plate 72, the length direction of the mounting rod 74 is parallel to the width direction of the bottom plate 42, and the mounting rod 74 is hinged with a hinge rod hinged to the handle 73. The hinge points between the handle 73 and the mounting rod 74 are arranged diagonally.

[0041] In this embodiment, the pressing head 75 is fixedly connected with a mounting screw 751. A second through groove 741 is formed in the upper surface of the mounting rod 74 along its height direction. The length direction of the second through groove 741 is parallel to the length direction of the mounting rod 74. The mounting screw 751 is inserted into the second through groove 741, and two nuts 752 respectively abutting against the upper and lower surfaces of the mounting rod 74 are threadedly connected to the mounting screw 751, so as to adjust the position of the pressing head in the height direction according to requirements.

[0042] Refer to Figure 6 , wherein, the guiding structure 8 is used to drive the handle 73 to rotate along the hinge point hinged to the second fixing plate 72. Specifically, the guiding structure 8 includes a support rod 81, a cross plate 82, a third fixing plate 83, a guiding seat 84, a guiding rod 85 and a spring 86. The length direction of the support rod 81 is parallel to the height direction of the bracket 2. The support rod 81 is fixedly connected to the side wall of the bracket 2. The length direction of the cross plate 82 is parallel to the width direction of the bracket 2. The cross plate 82 is fixedly connected to the upper end of the support rod 81 and extends above the profile 1. The length direction of the third fixing plate 83 is parallel to the length direction of the bracket 2. The third fixing plate 83 is fixedly connected to the side wall of the cross plate 82 close to the passive feeding trolley 4.

[0043] In this embodiment, the length direction of the guide seat 84 is parallel to the length direction of the fixed plate. A guide surface 841 is provided on the surface of the guide seat 84 away from the third guide plate. The upper end of the handle 73 abuts against the guide surface 841. The distance between the guide surface 841 and the third fixed plate 83 gradually increases in the direction close to the cross plate 82. Further, a limiting block 842 is fixedly connected to the end of the guide surface 841 away from the cross plate 82. It should be noted that the limiting block 842 can be an elastic cushion block.

[0044] Among them, two guide rods 85 are arranged along the length direction of the third fixed plate 83. One end of the guide rod 85 is fixedly inserted through the third fixed plate 83, and the other end of the guide rod 85 is slidably inserted through the guide seat 84. A third through groove 843 is formed through the upper end surface of the guide seat 84 along its height direction. The guide rod 85 is inserted into the third through groove 843. A spring 86 is coaxially sleeved on the guide rod 85, and both ends of the spring 86 are fixedly connected to the third fixed plate 83 and the guide seat 84 respectively.

[0045] Referring to Figure 7 , a second positioning roller 9 is provided at one end of the bracket 2 away from the passive feeding trolley 4. Two second positioning rollers 9 are provided and are respectively arranged on both sides of the profile 1. A second adjusting assembly 10 for adjusting the positions of the two second positioning rollers 9 in the width direction of the bracket 2 is provided on the bracket 2. A second mounting frame 23 for mounting the second adjusting assembly 10 is fixedly connected to the upper end surface of the bracket 2. The second adjusting assembly 10 specifically includes a second lead screw 101 rotatably passing through both ends of the second mounting frame 23, a second sliding plate 102 slidably connected to the second mounting frame 23, and a second hand wheel 103 coaxially and fixedly connected to the second lead screw 101. The second lead screw 101 is arranged in the same way as the first lead screw 61.

[0046] The implementation principle of a semi-automatic feeding and positioning workbench for a molding machine in an embodiment of the present application is as follows: By providing the first positioning roller 5 and the first adjusting assembly 6, the profile 1 is positioned, and it is also convenient to adjust the position between the two first positioning rollers 5 according to the width of the profile 1 through the first adjusting assembly 6 to limit the displacement of the profile 1 in the horizontal direction. Among them, after the profile 1 is pressed against the passive feeding trolley 4 by the clamp 7, when the subsequent molding machine drives the profile 1 to move forward, since the passive feeding trolley 4 is slidably connected to the guide rail 3 and slides along the length direction of the bracket 2, the passive feeding trolley 4 is driven to move towards the molding machine, which can reduce the possibility of the profile 1 having a displacement in the height direction during the feeding process and improve the bending effect of the profile 1. As the feeding increases, the clamping ability is limited. Therefore, when the passive feeding trolley 4 is driven to the guiding structure 8, the clamp 7 is driven to rotate away from the profile 1 to release the pressing on the profile 1, so that the remaining profile 1 can be bent.

[0047] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereby. Therefore, all equivalent changes made according to the structure, shape, and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A semi-automatic feeding and positioning workbench for a molding machine, characterized in that: It includes a bracket (2), a guide rail (3) arranged on the bracket (2), and a passive feeding trolley (4) slidably connected to the guide rail (3). A support roller (21) for supporting the profile (1) is rotatably connected to the upper surface of the bracket (2). A plurality of the support rollers (21) are arranged at intervals along the length direction of the bracket (2). First positioning rollers (5) are arranged on the upper surface of the passive feeding trolley (4) on both sides of the profile (1). A first adjusting component (6) for adjusting the distance between the first positioning roller (5) and the profile (1) is arranged on the passive feeding trolley. A clamp (7) for pressing against the profile (1) is arranged on the passive feeding trolley (4). A guiding structure (8) is arranged on the bracket (2), and the guiding structure (8) is used to drive the clamp (7) to rotate away from the profile (1) to release the pressing on the profile (1).

2. The semi-automatic feeding and positioning workbench for a molding machine according to claim 1, characterized in that: The passive feeding trolley (4) includes a sliding seat (41) slidably connected to the guide rail (3) and a bottom plate (42) arranged on the sliding seat (41). An installation plate (421) for the first adjusting component (6) is arranged on the lower surface of the bottom plate (42). The first adjusting component (6) includes a first lead screw (61) rotatably passing through the installation plate (421), a first sliding plate (62) slidably connected to the bottom plate (42), and a first handwheel (63) fixedly connected to the first lead screw (61). The first lead screw (61) is threadedly passed through the first sliding plate (62). A fixing rod connected to the first sliding plate (62) protrudes from the lower end of the first positioning roller (5). A first through slot (422) through which the fixing rod passes is formed in the upper surface of the bottom plate (42) along its width direction.

3. The semi-automatic feeding and positioning workbench for a molding machine according to claim 2, characterized in that: A plurality of the first positioning rollers (5) are arranged at intervals along the length direction of the passive feeding trolley (4). The length direction of the first sliding plate (62) is parallel to the length direction of the passive feeding trolley (4). The fixing rods on a plurality of the first positioning rollers (5) on one side are fixedly connected to the same first sliding plate (62).

4. The semi-automatic feeding and positioning workbench for a molding machine according to claim 3, characterized in that: The length direction of the installation plate (421) is parallel to the length direction of the bottom plate (42). Two first lead screws (61) are arranged at intervals along the length direction of one side of the installation plate (421). The first adjusting component (6) further includes two chain wheels (64) respectively coaxially sleeved on the two first lead screws (61) and a chain (65) wound around the two chain wheels (64).

5. A semi-automatic feeding and positioning workbench for a molding machine according to claim 1, characterized in that: The fixture (7) includes a first fixed plate (71) fixedly connected to the upper surface of the passive feeding trolley (4), a second fixed plate (72) vertically connected to the first fixed plate (71), a handle (73) hinged to the lower end of the second fixed plate (72), a mounting rod (74) hinged to the upper end of the second fixed plate (72), and a pressing head (75) provided at one end of the mounting rod (74) away from the second fixed plate (72). The length direction of the handle (73) is parallel to the height direction of the second fixed plate (72). An articulated rod hinged to the handle (73) is hinged to the mounting rod (74). The hinge points between the handle (73) and the mounting rod (74) are arranged diagonally. The guiding structure (8) is used to drive the handle (73) to rotate along the hinge point hinged to the second fixed plate (72).

6. The semi-automatic feeding and positioning workbench for a molding machine according to claim 5, wherein: The guiding structure (8) includes a support rod (81) fixedly connected to the bracket (2), a cross plate (82) fixedly connected to the support rod (81) extending above the profile (1), a third fixed plate (83) vertically fixed to the side wall of the cross plate (82) close to the side wall of the passive feeding trolley (4), and a guiding seat (84) provided on one side wall of the third fixed plate (83) close to the support rod (81). A guiding surface (841) is provided on the surface of the guiding seat (84) away from the third guiding plate. The upper end of the handle (73) abuts against the guiding surface (841). The distance between the guiding surface (841) and the third fixed plate (83) gradually increases in the direction close to the cross plate (82).

7. A semi-automatic feeding and positioning workbench for a molding machine according to claim 6, characterized in that: The guiding structure (8) further includes a guiding rod (85) fixedly penetrating through the third fixed plate (83) and a spring (86) coaxially sleeved on the guiding rod (85). One end of the guiding rod (85) away from the third fixed plate (83) slidably penetrates through the guiding seat (84). A third through slot (843) is provided through the upper end surface of the guiding seat (84) along its own height direction. The guiding rod (85) is inserted into the third through slot (843). The two ends of the spring (86) are respectively fixedly connected to the third fixed plate (83) and the guiding seat (84).

8. A semi-automatic feeding and positioning workbench for a molding machine according to claim 1, characterized in that: A second positioning roller (9) is provided at one end of the bracket (2) away from the passive feeding trolley (4). There are two second positioning rollers (9) which are respectively arranged on both sides of the profile (1). A second adjusting assembly (10) for adjusting the positions of the two second positioning rollers (9) in the width direction of the bracket (2) is provided on the bracket (2).

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