Excavator lower frame welding tool and using method thereof

Abstract

This application discloses a welding fixture for an excavator underframe and its usage method. A connecting rod is rotatably connected to the input ends of the first and second clamping rings. A first limiting seat and a second limiting seat are threaded onto the lead screw. A first push rod is provided on the side edge of the first limiting seat, and the first push rod is connected to the input end of the corresponding limiting plate. A second push rod is provided on the second limiting seat, and the second push rod is connected to the clamping plate. This design allows the underframe to be divided into multiple components placed on a crossbeam. The first clamping ring, second clamping ring, limiting plate, and clamping plate clamp and limit the different positions, thereby fixing them in place. Then, other components are welded onto the fixture. During component installation, the welding position on the back side of the component is not obstructed, allowing for normal welding even after flipping, thus improving welding efficiency and facilitating welding.

Description

Technical Field

[0001] This application relates to the field of underframe welding fixture technology, and in particular to an excavator underframe welding fixture and its usage method. Background Technology

[0002] Excavators are common construction machines widely used in building, road construction, mining, and other engineering fields, primarily for excavation operations. Excavators are widely used, operate in harsh environments, and are subjected to complex forces. An excavator mainly consists of several major parts, including the upper and lower frames, working device, hydraulic system, electrical system, and cab.

[0003] The underframe consists of a base frame, track beams, and a central cylinder. When welding the excavator underframe, the main body of the underframe needs to be fixed to the fixture with bolts. Then, the accessories are placed on the main body and welded by the welding head. During the welding process, the welding position is adjusted by rotating the equipment. When welding the back side, the main body of the underframe is disassembled and rotated. This way of placing the workpiece in the welding fixture restricts the welding process and makes it less flexible and convenient. Summary of the Invention

[0004] One of the objectives of this application is to provide a welding fixture for an excavator underframe and a method for using it.

[0005] To achieve the above objectives, the technical solution adopted in this application is as follows: a welding fixture for an excavator underframe and its usage method, comprising a machine tool, a CNC box, a welding head, a first servo motor, and a second servo motor. The machine tool is provided with a fixed seat, a crossbeam is rotatably connected to the fixed seat, a lead screw is rotatably connected to the side edge of the crossbeam, a movable seat is threaded onto the lead screw, a first clamping ring and a second clamping ring are rotatably connected to each side of the movable seat, a connecting rod is rotatably connected to the input end of the first clamping ring and the second clamping ring, a first limiting seat and a second limiting seat are threaded onto the lead screw, a first push rod is provided on the side edge of the first limiting seat, the first push rod is connected to the input end of the corresponding limiting plate, a second push rod is provided on the second limiting seat, and the second push rod is connected to the clamping plate.

[0006] Preferably, a second gear is provided on the input end of the horizontal head, and a first gear is meshed on the side edge of the second gear. The first gear is located at the output end of the first servo motor, and the first servo motor is detachably connected to a corresponding fixed base. The second servo motor is detachably connected to the second gear.

[0007] Preferably, the output end of the second servo motor is connected to a lead screw, and a side groove is provided on the side edge of the cross platform corresponding to the lead screw. The lead screw is arranged along the length of the side groove and is parallel to the side groove. A side seat is provided on the cross platform, and a corresponding rotating seat is rotatably connected to one end of the side seat.

[0008] Preferably, a connecting rod is fixedly connected to one end of the rotating seat. The connecting rod and the rotating seat are arranged in a T-shape. One end of the connecting rod is rotatably connected to a linkage rod. The linkage rod is arranged in an L-shape. One end of the linkage rod is set on the corresponding first retaining ring and second protection. The linkage rod is rotatably connected to the extension seat.

[0009] Preferably, the extension seat is mounted on a movable seat, the movable seat is located in the side groove of the cross platform, the cross platform has a top groove, a limit rod is provided in the top groove, the limit rod is arranged along the length of the side groove, the limit rod is parallel to the cross platform, a slide block is slidably connected in the top groove, and the limit rod is slidably connected in the slide block.

[0010] Preferably, a limiting plate is provided at one end of the slide block, the limiting plate is parallel to the cross platform, and a first push rod is rotatably connected to the slide block of the limiting plate, the first push rod being inclined.

[0011] Preferably, the clamping plate is located between the two limiting plates, the clamping plate and the limiting plates are parallel to each other, and a second push rod is rotatably connected to the side edge of the clamping plate, the second push rod being inclined.

[0012] Preferably, the output end of the clamp is provided with a rubber pad, the rubber pad is arranged along the length of the clamp, and a guide rod is provided on one end face of the clamp, the guide rod is vertically connected to the clamp.

[0013] Preferably, the guide rod is parallel to the cross platform, one end of the guide rod faces into the side groove of the cross platform, and the guide rod facing into the side groove is slidably connected in the corresponding side groove. The guide rod is located at both ends of the clamping plate.

[0014] A method for using a welding fixture for an excavator underframe includes the following steps:

[0015] S1: The lower frame can be disassembled into different parts such as track beams, underframe, and intermediate cylinder. Then, the parts are placed on the machine tool's crossbeam. After the underframe of the lower frame is placed between the limit plates of the crossbeam, the second servo motor is started to move the limit plates and clamps to the side edge of the underframe of the lower frame, so that the underframe can be fixed and limited. The track beams on both sides and the intermediate cylinder of the upper and lower parts can be welded at the welding position of the underframe.

[0016] S2: When welding the underframe, the track beam can also be selected for placement and fixation. The track beam is placed between the limiting plates, and then the second servo motor is started. The lead screw will rotate. After the limiting plates and clamps move, the track beam is clamped and limited. Then the underframe and the middle cylinder of the upper and lower parts are placed and fixed. During the rotation of the lead screw, the first and second clamps will rotate. The first and second clamps of the two side fixing seats will rotate relative to each other. The track beam can limit the displacement and achieve centering.

[0017] S3: When welding the underframe, the middle cylinder can also be selected for placement. The middle cylinder is placed between the two cross platforms. The second servo motor is started, and the second servo motor drives the lead screw to rotate. When the moving seat moves along the lead screw, it drives the first and second clamping rings to move. During the movement, the positions of the connecting rod and the rotating seat remain unchanged. The connecting rod pulls the linkage rod to rotate. When the linkage rod rotates, the first and second clamping rings will rotate towards the middle cylinder position, and the middle rotating cylinder will be fixed. Then, the underframe and track beam are placed for welding.

[0018] Compared with the prior art, the beneficial effects of this application are as follows:

[0019] This solution involves setting a fixed base on the machine tool, which can then mount a crossbeam. The second gear on the crossbeam meshes with the first gear on the first servo motor, causing the crossbeam to rotate. The lower frame can be rotated by the first servo motor when placed in different positions on the crossbeam. A lead screw is mounted on the crossbeam, located at the output end of the second servo motor. The second servo motor moves the moving seat, the first limit seat, and the second limit seat. When the moving seat moves, it rotates the first and second clamping rings, which then surround the middle cylinder of the lower frame, clamping it against the outer edge of the cylinder. The rotation of the lead screw also moves the first and second limit seats, causing the limit plates and clamping plates to move outwards. The lower frame's base frame or track beam can then be fixed between the limit plates. During welding, any welding position can be welded without restriction, eliminating the need for disassembly and repositioning before welding, thus facilitating welding and improving efficiency.

[0020] This solution involves setting a side seat on the cross platform, with a rotating seat rotatably connected to the side seat. The position of the rotating seat remains unchanged, allowing it to rotate around the side seat. A connecting rod is connected to the rotating seat, with one end of the connecting rod rotatably connected to a linkage rod. The linkage rod is located on a first and second clamping ring, and is rotatably connected to the extension seat of a movable seat. The movable seat then drives the first and second clamping rings to move. During this movement, the connecting rod pulls the linkage rod, causing it to rotate. As the linkage rod rotates, the first and second clamping rings also rotate, allowing them to rotate towards the central cylindrical position of the lower frame, thereby clamping and fixing it in place. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 .

[0022] Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 .

[0023] Figure 3 This is a schematic diagram of the structure of the first retaining ring in this invention.

[0024] Figure 4 This is a schematic diagram of the connection of the rubber pad in this invention.

[0025] Figure 5 This is a schematic diagram of the connection of the limiting rod in this invention.

[0026] Figure 6 This is a magnified schematic diagram of region A in this invention.

[0027] Figure 7 This is a schematic diagram of the enlarged structure of region B in this invention.

[0028] In the diagram: 1. Machine tool; 2. CNC box; 3. Fixed seat; 4. Welding head; 5. Cross table; 6. First servo motor; 7. First gear; 8. Second servo motor; 9. Second gear; 10. First retaining ring; 11. Second retaining ring; 12. Limiting plate; 13. Rotating seat; 14. Side seat; 15. Side groove; 16. Lead screw; 17. Moving seat; 18. Connecting rod; 19. Linkage rod; 20. Extension seat; 21. Rubber pad; 22. Top groove; 23. First limiting seat; 24. First push rod; 25. Slide seat; 26. Second push rod; 27. Guide rod; 28. Clamping plate; 29. ​​Second limiting seat; 30. Limiting rod. Detailed Implementation

[0029] The present application will be further described below with reference to specific embodiments. It should be noted that, without conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0030] In the description of this application, it should be noted that the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., which indicate the orientation and positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and should not be construed as limiting the specific protection scope of this application.

[0031] It should be noted that the terms "first," "second," etc., in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. Example 1

[0032] like Figures 1 to 7 As shown, the present invention discloses a welding fixture for an excavator underframe and its usage method, comprising a machine tool 1, a CNC box 2, a welding head 4, a first servo motor 6, and a second servo motor 8. A fixed base 3 is mounted on the machine tool 1, and a crossbeam 5 is rotatably connected to the fixed base 3. A lead screw 16 is rotatably connected to the side edge of the crossbeam 5, and a movable seat 17 is threaded onto the lead screw 16. A first retaining ring 10 and a second retaining ring 11 are rotatably connected to each side of the movable seat 17. A connecting rod 18 is rotatably connected to the input ends of the first retaining ring 10 and the second retaining ring 11. A first limiting seat 23 and a second limiting seat 29 are threaded onto the lead screw 16, respectively. The first limiting seat 23... A first push rod 24 is provided on the side edge of the frame, and the first push rod 24 is connected to the input end of the corresponding limiting plate 12. A second push rod 26 is provided on the second limiting seat 29, and the second push rod 26 is connected to the clamping plate 28. By setting up the frame, the lower frame can be divided into multiple parts and placed on the cross platform 5. The first clamping ring 10, the second clamping ring 11, the limiting plate 12 and the clamping plate 28 are used to clamp and limit the different positions, thereby fixing the different positions. Then, other different parts are welded on it. When the parts are installed, the welding position on the back side of the parts will not be blocked, so that they can be welded normally after being flipped over, thereby improving welding efficiency and facilitating welding.

[0033] like Figure 2 As shown, a second gear 9 is provided on the input end of the horizontal head, and a first gear 7 is meshed on the side edge of the second gear 9. The first gear 7 is located at the output end of the first servo motor 6. The first servo motor 6 is detachably connected to the corresponding fixed base 3. A second servo motor 8 is detachably connected to the second gear 9. Transmission can be achieved through the meshing of the first gear 7 and the second gear 9.

[0034] As an optional solution, in one embodiment of the present invention, such as Figure 3 As shown, the output end of the second servo motor 8 is connected to a lead screw 16. A side groove 15 is provided on the side edge of the cross platform 5 corresponding to the lead screw 16. The lead screw 16 is arranged along the length of the side groove 15 and is parallel to the side groove 15. A side seat 14 is provided on the cross platform 5. One end of the side seat 14 is rotatably connected to the corresponding rotating seat 13. The movement of the moving seat 17, the first limiting seat 23 and the second limiting seat 29 can be realized through the lead screw 16.

[0035] In implementation, a fixed seat 3 is set on the machine tool 1, and the crossbeam 5 can be installed on the fixed seat 3. The second gear 9 on the crossbeam 5 will mesh with the first gear 7 on the first servo motor 6. The first servo motor 6 can drive the entire crossbeam to rotate. When the lower frame is placed on the crossbeam 5 at different positions, it can be rotated by the first servo motor 6. The crossbeam 5 is equipped with a lead screw 16, which is located at the output end of the second servo motor 8. The second servo motor 8 can drive the moving seat 17, the first limit seat 23, and the second limit seat 29 to move. When the moving seat 17 moves, it... The first clamping ring 10 and the second clamping ring 11 can rotate, and the first clamping ring 10 and the second clamping ring 11 can surround the middle cylinder of the lower frame, thereby clamping it on the outer side edge of the middle cylinder. When the lead screw 16 rotates, the first limit seat 23 and the second limit seat 29 will also move. When they move, the limit plate 12 and the clamping plate 28 will move outward, and the underframe or track beam of the lower frame can be placed between the limit plates 12 for fixation. During welding, the welding position can be welded without restriction, and there is no need to disassemble and adjust the position before welding, which facilitates welding and improves efficiency. Example 2

[0036] like Figure 4 , Figure 5 and Figure 6 As shown, based on Embodiment 1, the present invention provides a technical solution: a connecting rod 18 is fixedly connected to one end of the rotating seat 13, the connecting rod 18 and the rotating seat 13 are arranged in a T-shape, one end of the connecting rod 18 is rotatably connected to the linkage rod 19, the linkage rod 19 is arranged in an L-shape, one end of the linkage rod 19 is set on the corresponding first retaining ring 10 and second protection, the linkage rod 19 is rotatably connected to the extension seat 20, and the connection with the connecting rod 18 can be realized through the linkage rod 19, the connecting rod 18 can drive the linkage rod 19 to rotate; the extension seat 20 is set on the movable seat 17, the movable seat 17 is located in the side groove 15 of the horizontal platform 5, the horizontal A top groove 22 is provided on the platform 5, and a limit rod 30 is provided in the top groove 22. The limit rod 30 is arranged along the length of the side groove 15 and is parallel to the horizontal platform 5. A slide block 25 is slidably connected in the top groove 22, and the limit rod 30 is slidably connected in the slide block 25. The limit rod 30 can limit the limit plate 12 to prevent tilting. A limit plate 12 is provided at one end of the slide block 25. The limit plate 12 is parallel to the horizontal platform 5. A first push rod 24 is rotatably connected to the slide block 25 of the limit plate 12. The first push rod 24 is inclined and can push and pull the slide block 25.

[0037] As an optional solution, in this embodiment, such as Figure 5 , Figure 6 and Figure 7As shown, the clamping plate 28 is located between the two limiting plates 12, and the clamping plate 28 and the limiting plates 12 are parallel to each other. The second push rod 26 is rotatably connected to the side edge of the clamping plate 28. The second push rod 26 is inclined and can pull and push the clamping plate 28 through the second push rod 26. The output end of the clamping plate 28 is provided with a rubber pad 21, which is arranged along the length of the clamping plate 28. A guide rod 27 is provided on one end face of the clamping plate 28. The guide rod 27 is vertically connected to the clamping plate 28 and can limit the clamping plate 28 through the guide rod 27. The guide rod 27 is parallel to the cross platform 5. One end of the guide rod 27 faces into the side groove 15 of the cross platform 5. The guide rod 27 facing into the side groove 15 is slidably connected into the corresponding side groove 15. The guide rod 27 is located at both ends of the clamping plate 28, and the lead screw 16 can be placed through the side groove 15.

[0038] In practice, a side seat 14 is set on the cross platform 5, and a rotating seat 13 is rotatably connected to the side seat 14. The position of the rotating seat 13 will not change, and the rotating seat 13 can rotate around the side seat 14. A connecting rod 18 is connected to the rotating seat 13, and one end of the connecting rod 18 is rotatably connected to the linkage rod 19. The linkage rod 19 is set on the first clamping ring 10 and the second clamping ring 11. The linkage rod 19 is rotatably connected to the extension seat 20 of the moving seat 17. The moving seat 17 will drive the first clamping ring 10 and the second clamping ring 11 to move. When moving, the connecting rod 18 will pull the linkage rod 19, and the linkage rod 19 will rotate. When the linkage rod 19 rotates, the first clamping ring 10 and the second clamping ring 11 will also rotate. The first clamping ring 10 and the second clamping ring 11 can rotate to the middle cylindrical position of the lower frame, thereby clamping and fixing it.

[0039] A method for using a welding fixture for an excavator underframe includes the following steps:

[0040] S1: The lower frame can be disassembled into different parts such as track beams, base frame and intermediate cylinder. Then the parts are placed on the horizontal table 5 of the machine tool 1. After the base frame of the lower frame is placed between the limiting plates 12 of the horizontal table 5, the second servo motor 8 is started to move the limiting plates 12 and the clamping plates 28 to the side edge of the base frame of the lower frame. The base frame can be fixed and limited. The track beams on both sides and the intermediate cylinder of the upper and lower parts can be welded at the welding position of the base frame.

[0041] S2: When welding the underframe, the track beam can also be selected for placement and fixation. The track beam is placed between the limiting plates 12, and then the second servo motor 8 is started. The lead screw 16 will rotate. After the limiting plates 12 and clamping plates 28 move, the track beam is clamped and limited. Then the base frame and the middle cylinder of the upper and lower parts are placed and fixed. During the rotation of the lead screw 16, the first clamping ring 10 and the second clamping ring 11 will rotate. The first clamping ring 10 and the second clamping ring 11 of the two side fixing seats 3 will rotate relative to each other. The track beam can limit the displacement and achieve centering.

[0042] S3: When welding the underframe, the middle cylinder can also be selected for placement. The middle cylinder is placed between the two cross platforms 5. The second servo motor 8 is started, and the second servo motor 8 drives the lead screw 16 to rotate. When the moving seat 17 moves along the lead screw 16, it drives the first clamping ring 10 and the second clamping ring 11 to move. When moving, the positions of the connecting rod 18 and the rotating seat 13 remain unchanged. The connecting rod 18 pulls the linkage rod 19 to rotate. When the linkage rod 19 rotates, the first clamping ring 10 and the second clamping ring 11 will rotate towards the middle cylinder position, and the middle rotating cylinder will be fixed. Then, the underframe and track beam are placed for welding.

[0043] The working principle of this invention is as follows: By setting a fixed seat 3 on the machine tool 1, the crossbeam 5 can be installed on the fixed seat 3. The second gear 9 on the crossbeam 5 will mesh with the first gear 7 on the first servo motor 6. The first servo motor 6 can drive the entire crossbeam to rotate. When the lower frame is placed on the crossbeam 5 at different positions, it can be rotated by the first servo motor 6. The crossbeam 5 is provided with a lead screw 16, which is located at the output end of the second servo motor 8. The second servo motor 8 can drive the moving seat 17, the first limiting seat 23, and the second limiting seat 29 to move. When the moving seat 17 moves, it can drive the first clamping ring 10 and the second clamping ring 11 to rotate. The first clamping ring 10 and the second clamping ring 11 can surround the middle cylinder position of the lower frame, thereby clamping it on the outer wall side edge of the middle cylinder. When the lead screw 16 rotates, the first limiting seat 23 and the second limiting seat 29 will also move. When they move, the limiting plate 12 and the clamping plate 28 will move outward, and the base frame or track beam of the lower frame can be placed in the limiting position. The plates 12 are fixed together, and welding can be performed at any position without restriction. There is no need to disassemble and adjust the position before welding, which facilitates welding and improves efficiency. A side seat 14 is set on the cross platform 5, and a rotating seat 13 is rotatably connected to the side seat 14. The position of the rotating seat 13 does not change, and the rotating seat 13 can rotate around the side seat 14. A connecting rod 18 is connected to the rotating seat 13, and one end of the connecting rod 18 is rotatably connected to the linkage rod 19. The linkage rod 19 is set on the first clamping ring 10 and the second clamping ring 11. The linkage rod 19 is rotatably connected to the extension seat 20 of the moving seat 17. The moving seat 17 will drive the first clamping ring 10 and the second clamping ring 11 to move. When moving, the connecting rod 18 will pull the linkage rod 19, and the linkage rod 19 will rotate. When the linkage rod 19 rotates, the first clamping ring 10 and the second clamping ring 11 will also rotate. The first clamping ring 10 and the second clamping ring 11 can rotate to the middle cylindrical position of the lower frame, thereby clamping and fixing it.

[0044] The basic principles, main features, and advantages of this application have been described above. Those skilled in the art should understand that this application is not limited to the above embodiments. The embodiments and descriptions in the specification are merely the principles of this application. Various changes and modifications can be made to this application without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection claimed by this application is defined by the appended claims and their equivalents.

Claims

1. A welding fixture for an excavator underframe, comprising a machine tool (1), a CNC box (2), a welding head (4), a first servo motor (6), and a second servo motor (8), characterized in that, The machine tool (1) is provided with a fixed seat (3), and a cross platform (5) is rotatably connected to the fixed seat (3). A lead screw (16) is rotatably connected to the two side edges of the cross platform (5). A movable seat (17) is threaded onto the lead screw (16). A first retaining ring (10) is rotatably connected to one side of the movable seat (17), and a second retaining ring (11) is rotatably connected to the other side of the movable seat (17). A connecting rod (18) is rotatably connected to the input end of the first retaining ring (10) and the second retaining ring (11). A first limiting seat (23) and a second limiting seat (29) are threaded onto the lead screw (16). A first push rod (24) is provided on the side edge of the first limiting seat (23). The first push rod (24) is connected to... The corresponding input end of the limiting plate (12), the second limiting seat (29) is provided with a second push rod (26), the second push rod (26) is connected to the clamp plate (28), the input end of the cross platform (5) is provided with a second gear (9), the side edge of the second gear (9) is meshed with a first gear (7), the first gear (7) is provided at the output end of the first servo motor (6), the first servo motor (6) is detachably connected to the corresponding fixed seat (3), the second gear (9) is detachably connected to a second servo motor (8), the output end of the second servo motor (8) is connected with a lead screw (16), the side edge of the cross platform (5) corresponding to the lead screw (16) is provided with a side groove (15), the lead screw ( 16) The lead screw (16) is arranged along the length of the side groove (15) and is parallel to the side groove (15). A side seat (14) is provided on the cross platform (5). One end of the side seat (14) is rotatably connected to a corresponding rotating seat (13). One end of the rotating seat (13) is fixedly connected to a connecting rod (18). The connecting rod (18) and the rotating seat (13) are arranged in a T-shape. One end of the connecting rod (18) is rotatably connected to a linkage rod (19). The linkage rod (19) is arranged in an L-shape. One end of the linkage rod (19) is set on the corresponding first retaining ring (10) and second retaining ring (11). The linkage rod (19) is rotatably connected to an extension seat (20). The extension seat (20) is set on the moving seat. (17) The movable seat (17) is located in the side groove (15) of the horizontal platform (5). The horizontal platform (5) has a top groove (22). A limit rod (30) is provided in the top groove (22). The limit rod (30) is arranged along the length of the side groove (15). The limit rod (30) is parallel to the horizontal platform (5). A slide block (25) is slidably connected in the top groove (22). The limit rod (30) is slidably connected in the slide block (25). A limit plate (12) is provided at one end of the slide block (25). The limit plate (12) is parallel to the horizontal platform (5). A first push rod (24) is rotatably connected to the slide block (25) of the limit plate (12). The first push rod (24) is inclined.The clamping plate (28) is located between the two limiting plates (12), and the clamping plate (28) and the limiting plates (12) are parallel to each other. A second push rod (26) is rotatably connected to the side edge of the clamping plate (28), and the second push rod (26) is inclined.

2. The welding fixture for an excavator underframe as described in claim 1, characterized in that: A rubber pad (21) is provided at the output end of the clamp (28). The rubber pad (21) is arranged along the length of the clamp (28). A guide rod (27) is provided on one end face of the clamp (28). The guide rod (27) is vertically connected to the clamp (28).

3. The welding fixture for an excavator underframe as described in claim 2, characterized in that: The guide rod (27) is parallel to the cross platform (5). One end of the guide rod (27) faces the side groove (15) of the cross platform (5). The guide rod (27) facing the side groove (15) is slidably connected in the corresponding side groove (15). The guide rod (27) is located at both ends of the clamping plate (28).

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