Vehicle body welding fixture control system and method

Abstract

The invention is suitable for the technical field of clamps, and provides a vehicle body welding clamp control system and method. A fixing frame is installed at the upper end of the bottom plate, and a fixing shaft is installed on the side face of the fixing frame. According to the vehicle body welding clamp control system and method, the first supporting plate and the second supporting plate are arranged to be matched to conduct rotary welding on the sheet metal part, the trouble that the sheet metal part needs to be repeatedly fixed to be welded is avoided, meanwhile, the second supporting plate can conduct rotary positioning, and therefore the sheet metal part needing to be obliquely welded can be conveniently fixed, and the welding efficiency is improved. And by arranging the pressing plate, when the clamping plate makes contact with the sheet metal part, along with continuous pushing of the electric air cylinder, the clamping plate can slide downwards at the moment, so that the pressing plate is pulled downwards, the pressing plate tightly presses the upper end of the sheet metal part, bi-directional fixing of the sheet metal part can be achieved through the arrangement, and therefore the sheet metal part is more stable and not prone to deviation in the welding process.

Description

Technical Field

[0001] The invention belongs to the technical field of fixtures, and in particular relates to a control system and method for a vehicle body welding fixture. Background Art

[0002] The fixture is an auxiliary condition for production in the manufacturing industry. The main purpose of the fixture is to quickly and accurately position the workpiece and properly support and maintain it, so that all workpieces produced on the same fixture are fixed within a specific range to ensure the precision and interchangeability of the product. In the process of automobile welding, the plate needs to be placed on the fixture to clamp the weldment for welding. Some clamps are electronically controlled and some are mechanically clamped. With the rapid development of automobile assembly automation technology, the existing technology usually uses pneumatic control of cylinders for clamping.

[0003] At present, the welding fixtures used for automotive sheet metal parts are too simple in function, usually only having a clamping function, while sheet metal parts need to be welded on multiple sides. Therefore, after welding one side, the sheet metal parts need to be removed and turned over, and then the sheet metal parts need to be clamped and welded again. Repeated fixation can easily cause cracks in the new welds and reduce the welding efficiency of the sheet metal parts. On the other hand, some sheet metal parts need to be welded at an angle, but the existing fixtures are not convenient for fixing the sheet metal parts at an angle, which brings more inconvenience to the welding work. Summary of the invention

[0004] The present invention provides a vehicle body welding fixture control system, aiming to solve the problem that sheet metal parts need to be clamped repeatedly for welding and it is inconvenient to clamp sheet metal parts that need to be tilted for welding.

[0005] The present invention is implemented in this way. A car body welding fixture control system includes a base plate; a fixing frame is installed on the upper end of the base plate, a fixing shaft is installed on the side of the fixing frame, a sleeve is rotatably sleeved on the outside of the fixing shaft, a first support plate is installed on the side of the sleeve, a support frame is installed on the upper end of the base plate, a connecting shaft is rotatably installed on the top of the support frame, a second support plate is installed on the side of the connecting shaft, one end of the connecting shaft extends to the other side of the support frame and is connected to a fixing disk, a worm gear is sleeved on the outside of the fixing disk, a bracket is installed on the side of the support frame, and the bracket A first motor is installed at the upper end, and a worm is connected to the output shaft of the first motor. The worm is rotatably installed on the side of the support frame and meshes with the worm wheel. A controller is installed at the bottom of the support frame, and an electric cylinder is installed at the bottom center of the second support plate. A connecting block is installed at the output shaft port of the electric cylinder. Slide grooves are symmetrically provided on the surface of the second support plate, and a slider is slidably embedded in the slide groove, a splint is vertically inserted in the slider, and a connecting rod is hinged at the bottom of the splint, and the other end of the connecting rod is hingedly connected to the connecting block, and the second support plate has the same structure as the first support plate.

[0006] Preferably, the clamping plate is slidably connected to the sliding block, a connecting plate is installed on the upper end of the clamping plate, a pressing plate is installed on the top of the connecting plate, and the pressing plate is located on the top of the clamping plate.

[0007] Preferably, a slot is provided on the top of the splint, and the connecting plate is slidably inserted in the slot of the splint. A groove is provided on the top of the splint, and a pull rod is slidably inserted in the groove. The inner end of the pull rod is connected to a card block, and a spring is sleeved on the outside of the pull rod. The outer wall of the connecting plate is provided with a card slot matched with the card block, and the card block and the connecting plate are slidably inserted.

[0008] Preferably, the side wall of the connecting plate is provided with five groups of slots, and the five groups of slots are evenly spaced from top to bottom.

[0009] Preferably, a slide groove is provided on the surface of the base plate, and a screw rod is rotatably installed in the slide groove. A second motor is installed at the left end of the base plate, and the output shaft of the second motor is connected to the screw rod. A screw sleeve is sleeved on the outside of the screw rod, and the bottom of the support frame is installed on the top of the screw sleeve.

[0010] Preferably, an electronic level is installed at the left end of the fixed plate, the electronic level is electrically connected to the controller, and the controller is electrically connected to the on / off switch of the first motor.

[0011] Preferably, two groups of limit blocks are symmetrically installed at the bottom of the clamping plate, and the width of the limit blocks is smaller than the width of the sliding groove on the surface of the second supporting plate.

[0012] Preferably, a positioning groove is provided on the top of the sleeve, and a latch is installed on the top of the fixing frame.

[0013] Also disclosed is a control method for the above-mentioned vehicle body welding fixture, comprising the following steps:

[0014] S1: When the device is used, the sheet metal to be welded is first placed on the surface of the first pallet and the second pallet, and then the electric cylinder is started through the controller. The electric cylinder pushes the connecting block downward. At this time, the two sets of connecting rods pull the clamping plate inward to clamp the sheet metal. When the two sheet metals are clamped and fixed, subsequent welding can be carried out. When the two sheet metals need to be welded at an angle, the first motor can be started at this time. The first motor drives the connecting shaft to rotate through the cooperation between the worm and the worm gear, and then drives the second pallet to rotate, and can be positioned at any angle, so that the welding of the sheet metal is more convenient. The first pallet is also movably installed. When the two sheet metals are welded and connected to one piece, the first pallet can be driven to rotate, so as to facilitate the welding of the surrounding surfaces of the two sheet metals. When the clamping plate contacts the sheet metal, as the electric cylinder continues to push, the clamping plate will slide downward, thereby pulling down the pressing plate, so that the pressing plate presses the upper end of the sheet metal. This setting can achieve two-way fixation of the sheet metal, so that it is more stable during welding and not easy to deviate.

[0015] S2: By opening five slots on the side wall of the connecting plate, the pressure plate can be adjusted to five different heights for fixing. The bottom of the support frame is installed on the top of the screw sleeve, and the support frame is installed on the upper end of the screw sleeve. The second motor can be started, and the second motor drives the screw to rotate, and the screw sleeve slides horizontally under the action of the screw thread, thereby driving the second pallet to move horizontally. Through this setting, the distance between the second pallet and the first pallet can be adjusted, so as to facilitate the clamping of sheet metal parts of different sizes. After the sheet metal parts are welded, in order to ensure the normal welding of subsequent sheet metal parts, the second pallet needs to be adjusted to a horizontal state. Here, the electronic level can be used to turn off the first motor through the controller when the second pallet is in a horizontal state, thereby ensuring that the second pallet is reset to a horizontal state each time.

[0016] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0017] 1. The device can perform rotational welding on sheet metal parts by setting the first support plate and the second support plate in cooperation, avoiding the trouble of repeatedly fixing the sheet metal parts for welding. At the same time, the second support plate can be rotated and positioned, so as to facilitate the fixation of sheet metal parts that need to be tilted for welding, thereby improving the practicality of the device. By setting a pressure plate, when the clamping plate contacts the sheet metal part, as the electric cylinder continues to push, the clamping plate will slide downward, thereby pulling the pressure plate down and pressing the upper end of the sheet metal part. Through this setting, the sheet metal part can be fixed in both directions, making it more stable during welding and not easy to deviate.

[0018] 2. The connecting plate is fixed by setting a spring and a card block. The pull rod can be pulled out of the card block from the card slot of the connecting plate. At this time, the connecting plate and the pressure plate can be pulled upward and removed as a whole. Due to the various shapes of sheet metal parts, it is necessary to frequently replace the pressure plates corresponding to the sheet metal parts. This installation method can make the disassembly and replacement of the pressure plate more convenient. By opening five card slots on the side wall of the connecting plate, the pressure plate can be adjusted to five different heights accordingly, which can facilitate the fixing of thinner or thicker sheet metal parts. By setting screws and screw sleeves, the distance between the second support plate and the first support plate can be adjusted, which is convenient for clamping sheet metal parts of different sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a three-dimensional structural schematic diagram of the present invention;

[0020] Figure 2 It is a front cross-sectional structural schematic diagram of the present invention;

[0021] Figure 3 is a schematic diagram of a side cross-sectional structure of a second support plate of the present invention;

[0022] Figure 4 is a cross-sectional schematic diagram of a slider connection structure of the present invention;

[0023] Figure 5 The present invention Figure 3 A schematic diagram of the structure enlargement in the middle;

[0024] In the figure: 1, base plate; 2, fixing frame; 3, fixing shaft; 4, sleeve; 5, first support plate; 6, supporting frame; 7, connecting shaft; 8, second support plate; 9, fixing plate; 10, worm gear; 11, bracket; 12, first motor; 13, worm; 14, controller; 15, electric cylinder; 16, connecting block; 17, slider; 18, clamping plate; 19, connecting plate; 20, pressing plate; 21, pull rod; 22, clamping block; 23, spring; 24, screw; 25, second motor; 26, screw sleeve; 27, electronic level; 28, limit block; 29, connecting rod. DETAILED DESCRIPTION

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of this application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0026] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0027] The embodiment of the present invention provides a vehicle body welding fixture control system, such as Figure 1-5 As shown, it includes a bottom plate 1, a fixing frame 2 is installed on the upper end of the bottom plate 1, a fixing shaft 3 is installed on the side of the fixing frame 2, a sleeve 4 is rotatably sleeved on the outside of the fixing shaft 3, a first support plate 5 is installed on the side of the sleeve 4, a support frame 6 is installed on the upper end of the bottom plate 1, a connecting shaft 7 is rotatably installed on the top of the support frame 6, a second support plate 8 is installed on the side of the connecting shaft 7, one end of the connecting shaft 7 extends to the other side of the support frame 6 and is connected to a fixing disk 9, a worm gear 10 is sleeved on the outside of the fixing disk 9, and a first support plate 5 is installed on the side of the support frame 6. A bracket 11 is installed, a first motor 12 is installed on the upper end of the bracket 11, a worm 13 is connected to the output shaft of the first motor 12, the worm 13 is rotatably installed on the side of the support frame 6 and meshes with the worm wheel 10, a controller 14 is installed at the bottom of the bracket 11, an electric cylinder 15 is installed at the bottom center of the second support plate 8, a connecting block 16 is installed at the output shaft port of the electric cylinder 15, a slide groove is symmetrically opened on the surface of the second support plate 8, and a slider 17 is slidably embedded in the slide groove, and a vertically inserted slider 17 is inserted in the slider 17. There is a clamping plate 18, and a connecting rod 29 is hinged at the bottom of the clamping plate 18. The other end of the connecting rod 29 is hingedly connected to the connecting block 16. The second support plate 8 has the same structure as the first support plate 5. When the device is used, the sheet metal to be welded is first placed on the surface of the first support plate 5 and the second support plate 8, and then the electric cylinder 15 is started by the controller 14. The electric cylinder 15 pushes the connecting block 16 downward. At this time, the two groups of connecting rods 29 pull the clamping plate 18 inward, thereby clamping the sheet metal. When the two sheet metal clamps are fastened After being fixed, subsequent welding can be carried out. When two sheet metal parts need to be welded at an angle, the first motor 12 can be started. The first motor 12 drives the connecting shaft 7 to rotate through the cooperation between the worm 13 and the worm wheel 10, and then drives the second support plate 8 to rotate, and can be positioned at any angle, so that the welding of sheet metal parts is more convenient. The first support plate 5 is also movably installed. When the two sheet metal parts are welded and connected to one piece, the first support plate 5 can be driven to rotate, so as to facilitate the welding of the surrounding surfaces of the two sheet metal parts.

[0028] The clamping plate 18 is slidably connected to the slider 17, and a connecting plate 19 is installed on the upper end of the clamping plate 18. A pressure plate 20 is installed on the top of the connecting plate 19. The pressure plate 20 is located on the top of the clamping plate 18. By providing the pressure plate 20, when the clamping plate 18 contacts the sheet metal, as the electric cylinder 15 continues to push, the clamping plate 18 will slide downward, thereby pulling the pressure plate 20 down, so that the pressure plate 20 presses the upper end of the sheet metal. Through this setting, the sheet metal can be fixed in both directions, making it more stable during welding and not easy to shift.

[0029] A slot is provided at the top of the splint 18, and the connecting plate 19 is slidably inserted in the slot of the splint 18. A groove is provided at the top of the splint 18, and a pull rod 21 is slidably inserted in the groove. The inner end of the pull rod 21 is connected to a block 22, and a spring 23 is sleeved on the outside of the pull rod 21. The outer wall of the connecting plate 19 is provided with a slot adapted to the block 22, and the block 22 and the connecting plate 19 are slidably inserted. The pressing plate 20 is installed at the upper end of the splint 18 through the connecting plate 19, and the connecting plate 19 is fixed with the block 22 by the spring 23. The pull rod 21 can be pulled to pull the block 22 out of the slot of the connecting plate 19. At this time, the connecting plate 19 and the pressing plate 20 can be pulled out and removed upward as a whole. Due to the various shapes of sheet metal parts, it is necessary to frequently replace the pressing plate 20 corresponding to the sheet metal parts. This installation method can make the disassembly and replacement of the pressing plate 20 more convenient.

[0030] There are five groups of slots on the side wall of the connecting plate 19, and the five groups of slots are evenly spaced from top to bottom. By opening five slots on the side wall of the connecting plate 19, the pressing plate 20 can be adjusted to five different heights accordingly, so as to facilitate the fixing of thinner or thicker sheet metal parts.

[0031] A slide groove is provided on the surface of the base plate 1, and a screw rod 24 is rotatably installed in the slide groove. A second motor 25 is installed at the left end of the base plate 1. The output shaft of the second motor 25 is connected to the screw rod 24. A screw sleeve 26 is sleeved on the outside of the screw rod 24. The bottom of the support frame 6 is installed on the top of the screw sleeve 26. The support frame 6 is installed on the upper end of the screw sleeve 26. The second motor 25 can be started, and the second motor 25 drives the screw rod 24 to rotate, and the screw sleeve 26 slides horizontally under the action of the thread of the screw rod 24, thereby driving the second support plate 8 to move horizontally. Through this setting, the spacing between the second support plate 8 and the first support plate 5 can be adjusted, so as to facilitate the clamping of sheet metal parts of different sizes.

[0032] An electronic level 27 is installed at the left end of the fixed plate 9, and the electronic level 27 is electrically connected to the controller 14, and the controller 14 is electrically connected to the on / off switch of the first motor 12. By providing the electronic level 27, after the sheet metal welding is completed, in order to ensure the normal welding of subsequent sheet metal parts, the second pallet 8 needs to be adjusted to a horizontal state. Here, the electronic level 27 can be used to turn off the first motor 12 through the controller 14 when the second pallet 8 is in a horizontal state, thereby ensuring that the second pallet 8 is reset to a horizontal state each time.

[0033] Two sets of limit blocks 28 are symmetrically installed at the bottom of the splint 18. The width of the limit blocks 28 is smaller than the width of the slide groove on the surface of the second support plate 8. By setting the limit blocks 28, the limit blocks 28 can limit the splint 18 to prevent the splint 18 from sliding upward from the lower end of the slider 17.

[0034] A positioning groove is provided at the top of the sleeve 4, and a latch is installed at the top of the fixing frame 2. By installing the latch at the top of the sleeve 4, the first support plate 5 can be positioned and fixed, and can also rotate synchronously with the second support plate 8 through the sheet metal part.

[0035] Also disclosed is a control method for the above-mentioned vehicle body welding fixture, comprising the following steps:

[0036] S1: When the device is used, the sheet metal parts to be welded are first placed on the surfaces of the first support plate 5 and the second support plate 8, and then the electric cylinder 15 is started through the controller 14, and the electric cylinder 15 pushes the connecting block 16 downward. At this time, the two sets of connecting rods 29 pull the clamping plate 18 inward, thereby clamping the sheet metal parts. When the two sheet metal parts are clamped and fixed, subsequent welding can be carried out. When the two sheet metal parts need to be welded at an angle, the first motor 12 can be started at this time. The first motor 12 drives the connecting shaft 7 to rotate through the cooperation between the worm 13 and the worm wheel 10, thereby driving the second support plate 8 It can rotate and be positioned at any angle, thereby making the welding of sheet metal parts more convenient. The first support plate 5 is also movably installed. When two sheet metal parts are welded and connected together, the first support plate 5 can be driven to rotate, thereby facilitating the welding of the surrounding surfaces of the two sheet metal parts. When the clamping plate 18 contacts the sheet metal part, as the electric cylinder 15 continues to push, the clamping plate 18 will slide downward, thereby pulling down the pressing plate 20, so that the pressing plate 20 presses the upper end of the sheet metal part. Through this setting, the sheet metal part can be fixed in both directions, making it more stable during welding and not easy to shift.

[0037] S2: By opening five slots on the side wall of the connecting plate 19, the pressure plate 20 can be adjusted to five different heights for fixing. The bottom of the support frame 6 is installed on the top of the screw sleeve 26, and the support frame 6 is installed on the upper end of the screw sleeve 26. The second motor 25 can be started, and the second motor 25 drives the screw 24 to rotate, and the screw sleeve 26 slides horizontally under the action of the thread of the screw 24, thereby driving the second support plate 8 to move horizontally. Through this setting, the distance between the second support plate 8 and the first support plate 5 can be adjusted, so as to facilitate the clamping of sheet metal parts of different sizes. After the sheet metal parts are welded, in order to ensure the normal welding of subsequent sheet metal parts, the second support plate 8 needs to be adjusted to a horizontal state. Here, the electronic level 27 can be used to turn off the first motor 12 through the controller 14 when the second support plate 8 is in a horizontal state, thereby ensuring that the second support plate 8 is reset to a horizontal state each time.

[0038] It should be noted that, for the above-mentioned embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described order of actions, because according to the present invention, some steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0039] In the several embodiments provided in the present application, it should be understood that the disclosed devices can be implemented in other ways. For example, the device embodiments described above are merely schematic, such as the division of the above-mentioned units. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection between devices or units can be in the form of telecommunication or other forms.

[0040] The units described above as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. The above embodiments are only used to illustrate the technical scheme of the present invention, rather than to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in this field can still combine, add, delete or make other adjustments to the features in the embodiments of the present invention according to the situation without conflict, without making creative work, so as to obtain different other technical solutions that are essentially not separated from the concept of the present invention, and these technical solutions also belong to the scope of protection of the present invention.

Claims

1. A car body welding fixture control system, characterized in that: The invention comprises a base plate (1): a fixing frame (2) is installed on the upper end of the base plate (1), a fixing shaft (3) is installed on the side of the fixing frame (2), a sleeve (4) is rotatably sleeved on the outside of the fixing shaft (3), a first support plate (5) is installed on the side of the sleeve (4), a support frame (6) is installed on the upper end of the base plate (1), a connecting shaft (7) is rotatably installed on the top of the supporting frame (6), a second support plate (8) is installed on the side of the connecting shaft (7), one end of the connecting shaft (7) extends to the other side of the supporting frame (6) and is connected to a fixing plate (9), a worm gear (10) is sleeved on the outside of the fixing plate (9), a bracket (11) is installed on the side of the supporting frame (6), a first motor (12) is installed on the upper end of the bracket (11), and a second motor (12) is installed on the upper end of the bracket (11). The output shaft of a motor (12) is connected to a worm (13), and the worm (13) is rotatably mounted on the side of a support frame (6) and meshed with a worm wheel (10). A controller (14) is mounted at the bottom of the support frame (11). An electric cylinder (15) is mounted at the bottom center of the second support plate (8), and a connecting block (16) is mounted at the output shaft port of the electric cylinder (15). The surface of the second support plate (8) is symmetrically provided with sliding grooves, and a slider (17) is slidably embedded in the sliding groove. A clamping plate (18) is vertically inserted in the slider (17). A connecting rod (29) is hinged at the bottom of the clamping plate (18), and the other end of the connecting rod (29) is hingedly connected to the connecting block (16). The second support plate (8) has the same structure as the first support plate (5).

2. A vehicle body welding fixture control system as claimed in claim 1, characterized in that: The clamping plate (18) is slidably connected to the slider (17); a connecting plate (19) is installed at the upper end of the clamping plate (18); a pressing plate (20) is installed on the top of the connecting plate (19); and the pressing plate (20) is located on the top of the clamping plate (18).

3. A vehicle body welding fixture control system as claimed in claim 2, characterized in that: A slot is provided on the top of the splint (18), and the connecting plate (19) is slidably inserted in the slot of the splint (18). A groove is provided on the top of the splint (18), and a pull rod (21) is slidably inserted in the groove. The inner end of the pull rod (21) is connected to a clamping block (22), and the outside of the pull rod (21) is sleeved with a spring (23). The outer wall of the connecting plate (19) is provided with a clamping groove that matches the clamping block (22), and the clamping block (22) and the connecting plate (19) are slidably inserted.

4. A vehicle body welding fixture control system as claimed in claim 3, characterized in that: The side wall of the connecting plate (19) is provided with five groups of slots, and the five groups of slots are evenly spaced from top to bottom.

5. A vehicle body welding fixture control system as claimed in claim 1, characterized in that: A slide groove is provided on the surface of the base plate (1), and a screw rod (24) is rotatably installed in the slide groove. A second motor (25) is installed at the left end of the base plate (1), and the output shaft of the second motor (25) is connected to the screw rod (24). A screw sleeve (26) is sleeved on the outside of the screw rod (24), and the bottom of the support frame (6) is installed on the top of the screw sleeve (26).

6. A vehicle body welding fixture control system as claimed in claim 1, characterized in that: An electronic level (27) is installed at the left end of the fixed plate (9), and the electronic level (27) is electrically connected to the controller (14), and the controller (14) is electrically connected to the on / off switch of the first motor (12).

7. A vehicle body welding fixture control system as claimed in claim 1, characterized in that: Two groups of limit blocks (28) are symmetrically mounted on the bottom of the clamping plate (18), and the width of the limit blocks (28) is smaller than the width of the sliding groove on the surface of the second support plate (8).

8. A vehicle body welding fixture control system as claimed in claim 1, characterized in that: A positioning groove is provided on the top of the sleeve (4), and a latch is installed on the top of the fixing frame (2).

9. A control method for a vehicle body welding fixture according to any one of claims 1 to 8, characterized in that: The steps include: S1：。 S2：。

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