A processing tool capable of reducing embryo deformation

Abstract

The present application relates to a kind of processing tooling that can reduce embryo deformation, including a pair of side webs installed at the spindle box of lathe and the rectangular bridge plate of support at the end side of side web, vertical clamping part is equipped at the left side of bridge plate upper wall, end clamping part is equipped at the right side of bridge plate upper wall, vertical clamping part and end clamping part are used to clamp fork arm workpiece, vertical clamping part is used to positively clamp fork arm workpiece.The beneficial effects of the present application are: the processing tooling that can reduce embryo deformation, the end clamping part and fork arm workpiece are multi-point contact clamping, point contact clamping is used between end clamping part and fork arm workpiece, the area of contact is small, so as to reduce the stress area of reference when positioning connection, reduce the problem that product is caused by lateral stress when being pressed and leads to warping, even if the embryo reference of fork arm workpiece exists certain deformation, but using point-to-point stress mode, the influence caused by deformation is greatly compensated.

Description

Technical Field

[0001] This invention relates to the field of machining tooling technology, specifically to a machining tooling that can reduce the deformation of blanks. Background Technology

[0002] Fork arms are key load-bearing components in fields such as construction machinery and automobile chassis. Their machining accuracy directly affects the structural strength and operational safety of the entire machine. Their shape and structure dictate that the tooling needs to have multiple surface positioning functions in order to properly position the fork arm components. This machining tooling is used for positioning fork arms.

[0003] The conventional tooling positioning method uses several blank reference planes to position the bottom plane of the product. However, due to the deformation of the blank, the reference planes are not flat. When the pressure plates of some of the reference planes are pressed, due to the lateral force and the deformation of the blank, the blank surfaces of the remaining reference planes will lift up. This causes the product structure, which is far from the reference, to deviate significantly from its original position. The farther the distance, the greater the positional fluctuation, which poses a great hidden risk to subsequent processing. Summary of the Invention

[0004] The purpose of this invention is to provide a machining fixture that can reduce blank deformation, in order to solve the problem mentioned in the background art that the existing ordinary tooling positioning method uses several blank reference planes to position the bottom plane of the product. However, due to the deformation of the blank, the reference planes are not flat. When the pressure plates of some of the reference planes are pressed, due to the lateral force and the deformation of the blank, the blank surfaces of the remaining reference planes will lift up, causing the product structure far from the reference to deviate significantly from the original position. The farther the distance, the greater the positional fluctuation, which poses a great hidden risk to subsequent processing.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a machining fixture that can reduce blank deformation, comprising a pair of side connecting plates installed at the spindle box of a lathe and a rectangular bridge plate supported at the end of the side connecting plates. A vertical clamping part is provided on the left side of the upper wall of the bridge plate, and an end clamping part is provided on the right side of the upper wall of the bridge plate. Both the vertical clamping part and the end clamping part are used to clamp the fork arm workpiece. The vertical clamping part is used to clamp the fork arm workpiece in the forward direction, and the end clamping part is used to clamp the fork arm workpiece in the reverse direction. The end clamping part and the fork arm workpiece are clamped by multi-point contact.

[0006] Preferably, the side connecting plate is L-shaped and a supporting bridge plate is mounted at the bottom L-shaped opening. The bridge plate and the side connecting plate are fastened together by bolts, and a pair of through holes are provided on the right end wall of the bridge plate.

[0007] Preferably, a rectangular positioning plate is fixed to the left side of the upper wall of the bridge plate by a screw assembly, the vertical clamping part is located on the positioning plate, the screw assembly is a limiting screw, and four limiting screws are provided.

[0008] Preferably, the vertical clamping part includes a plug-in screw vertically threaded to the center end wall of the positioning plate, a C-shaped pressure plate sleeved on the outside of the plug-in screw, and a fixing nut threaded to the top end of the plug-in screw for pressing the pressure plate.

[0009] Preferably, the plug screw has flat end walls on both sides of the middle section, and the center of the clamping plate has an elliptical opening through the right wall, with the elliptical opening being roughly circular near the center.

[0010] Preferably, a rectangular lateral positioning base is fixed to the right side of the upper wall of the bridge plate near the through-hole. A connecting port is horizontally penetrating the top of the lateral positioning base. A lateral top block is movably arranged inside the connecting port. A concave-shaped notch is penetrating the right wall of the lateral top block. A rod head that is wider on the left and narrower on the right is rotatably connected at the concave notch.

[0011] Preferably, the front end of the connection port is rectangular and the rear end is threaded. The front end of the connection port is used to arrange the lateral top block and the rear end is used to thread the handle to be fixed to the rod head. The handwheel is fixed to the end wall of the handle away from the rod head. The rod nut is threaded to the outside of the handle. There are three lateral positioning bases, three lateral top blocks, three rod heads, three handwheels, three handles, and three rod nuts.

[0012] Preferably, the end clamping part includes three rectangular positioning pads fixed to the right side of the bridge plate near the through opening, which are used in conjunction with the lateral positioning base; a pressing screw threaded to the center end wall of the positioning pad; a stop rod threaded to the front side of the positioning pad near the pressing screw; a matching seat fixed to the positioning pad near the rear side of the pressing screw; a pressure plate connected to the top of the pressing screw via a screw seat; a spring arranged between the pressure plate and the positioning pad and sleeved on the outside of the pressing screw; and a positioning head fixed to the bottom end of the pressure plate and the top end wall of the matching seat.

[0013] Preferably, the positioning head is used to make point contact with the fork arm workpiece, and an elliptical notch is passed through the center of the pressure plate end wall for movably connecting the pressure screw. A bottom channel is opened on the bottom wall of the pressure plate for embedding the top head of the movably connecting stop rod. At the same time, three fixed seats that are adapted to the lateral positioning base and the positioning pad are fixedly connected to the right side of the bridge plate near the through opening. The fixed seats are rectangular, and a fixed head for abutting against the side wall of the fork arm workpiece is fixedly connected to the top side wall of the fixed seat.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: The end clamping part and the fork arm workpiece are clamped at multiple points. The end clamping part and the fork arm workpiece are clamped at points, with a small contact area, which reduces the force area of ​​the reference during positioning and connection, and reduces the problem of product tilting due to lateral force during clamping. Even if the blank reference of the fork arm workpiece has a certain deformation, the point-to-point force method can greatly compensate for the impact of deformation. The vertical clamping part and the end clamping part are used to clamp and position the fork arm workpiece in the forward and reverse directions, which facilitates processing of the fork arm workpiece in different positions, thereby achieving the purpose of dual-station processing of fork arm workpieces and higher processing efficiency. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a machining tooling that can reduce blank deformation according to the present invention; Figure 2 This is a three-dimensional structural diagram of the bridge plate and positioning plate of a machining fixture that can reduce blank deformation according to the present invention. Figure 3 This is a front view schematic diagram of the side connecting plate structure of a machining tooling that can reduce blank deformation according to the present invention. Figure 4 This is a three-dimensional structural diagram of the bottom of the side connecting plate of a machining fixture that can reduce blank deformation according to the present invention. Figure 5 This is a three-dimensional structural diagram of the side connecting plate and positioning pad of a machining fixture that can reduce blank deformation according to the present invention. Figure 6 This is a schematic diagram of the bridge plate structure of a machining tooling that can reduce blank deformation according to the present invention. Figure 7 This is a three-dimensional structural diagram of the handle and lateral positioning base of a machining fixture that can reduce blank deformation according to the present invention. Figure 8 This is a three-dimensional structural diagram of the pressure plate and fixing nut of a machining fixture that can reduce blank deformation according to the present invention. Figure 9 This is a three-dimensional structural diagram of the insertion screw and pressure plate of a machining fixture that can reduce blank deformation according to the present invention. Figure 10 This is a three-dimensional structural diagram of a positioning plate and a connecting screw for a machining fixture that can reduce blank deformation according to the present invention.

[0016] In the diagram: 1. Side connecting plate; 2. Bridge plate; 3. Through-hole; 4. Positioning plate; 5. Fork arm workpiece; 6. Insert screw; 7. Limiting screw; 8. Pressure plate; 9. Fixing nut; 10. Lateral positioning base; 11. Lateral top block; 12. Recessed slot; 13. Rod head; 14. Handwheel; 15. Hand lever; 16. Rod nut; 17. Positioning pad; 18. Pressing screw; 19. Stopping top rod; 20. Spring; 21. Pressure plate; 22. Plate notch; 23. Plate bottom track; 24. Matching seat; 25. Positioning head; 26. Fixing seat; 27. Fixing head. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0018] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention 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 therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] Please see Figure 1-10This invention provides a technical solution: a machining fixture that can reduce blank deformation, including a pair of side connecting plates 1 installed at the spindle box of a lathe and a rectangular bridge plate 2 supported at the end of the side connecting plates 1. A vertical clamping part is provided on the left side of the upper wall of the bridge plate 2, and an end clamping part is provided on the right side of the upper wall of the bridge plate 2. Both the vertical clamping part and the end clamping part are used to clamp the fork arm workpiece 5. The vertical clamping part is used to clamp the fork arm workpiece 5 in a forward direction, and the end clamping part is used to clamp the fork arm workpiece 5 in a reverse direction. The end clamping part and the fork arm workpiece 5 are clamped at multiple points. The point contact clamping method reduces the contact area, thereby decreasing the force-bearing area of ​​the reference during positioning and connection. This reduces the problem of product tilting due to lateral force during clamping. Even if the blank reference of the fork arm workpiece 5 has some deformation, the point-to-point force method can greatly compensate for the impact of deformation. At the same time, the vertical clamping part and the end clamping part are used to clamp and position the fork arm workpiece 5 in both directions, which facilitates processing of the fork arm workpiece 5 in different positions. This achieves the purpose of dual-station processing of the fork arm workpiece 5, resulting in higher processing efficiency. The side connecting plate 1 is L-shaped and a support bridge plate 2 is mounted at the bottom L-shaped opening. The bridge plate 2 and the side connecting plate 1 are fastened together by bolts. A pair of through holes 3 are through the right end wall of the bridge plate 2. The end side protrusion of the fork arm workpiece 5 can be accommodated in the through holes 3 when the fork arm workpiece 5 is placed in the opposite direction for clamping, which facilitates its placement. A rectangular positioning plate 4 is fixed to the left side of the upper wall of bridge plate 2 by a screw assembly. The vertical clamping part is located on the positioning plate 4. The screw assembly is a limiting screw 7, and four limiting screws 7 are provided to facilitate the disassembly and assembly of the positioning plate 4. The vertical clamping part includes an insertion screw 6 vertically threaded at the center end wall of the positioning plate 4, a C-shaped pressure plate 8 sleeved on the outside of the insertion screw 6, and a fixing nut 9 threaded at the top end of the insertion screw 6 for pressing the pressure plate 8. The two side walls of the middle part of the insertion screw 6 are both formed with straight end walls. Meanwhile, the center of the pressing plate 8 has an elliptical opening through the right wall. The elliptical opening is roughly circular near the center. The plug screw 6 is used to fit the fork arm workpiece 5 with the opening through the center after processing. The opening in the center of the fork arm workpiece 5 is fitted onto the plug screw 6. Then, the pressing plate 8 is fitted onto the plug screw 6 using the elliptical opening. At the same time, the threaded connection and fixing nut 9 are used to press the two fitted pressing plates 8 together, thereby pressing and positioning the fork arm workpiece 5 placed in the forward position, so that it can be stably processed after positioning. A rectangular lateral positioning base 10 is fixed to the right side of the upper wall of bridge plate 2 near the through-hole 3. A horizontal connection port extends through the top of the lateral positioning base 10, and a lateral top block 11 is movably arranged within the connection port. A recessed slot 12, shaped like a concave character, extends through the right wall of the lateral top block 11. A rod head 13, wider on the left and narrower on the right, is rotatably connected to the recessed slot 12. The front end of the connection port is rectangular, and the rear end is threaded. The front end of the connection port is used to accommodate the lateral top block 11, and the rear end is used for threaded connection to a handle 15, which is fixed to the rod head 13. A handwheel 14 is fixed to the end wall of the handle 15 away from the rod head 13. A rod nut 16 is threadedly connected to the outside of the handle 15. The base 10, the side top block 11, the rod head 13, the handwheel 14, the handle 15, and the rod nut 16 are all provided in threes. When the handwheel 14 rotates, it drives the rod head 13 and the handle 15 to rotate. The handle 15 is threaded into the threaded opening at the rear end of the connection port for threaded displacement. The side top block 11 is sleeved on the rod head 13 through the concave slot 12 to facilitate the rotation of the rod head 13. When the rod head 13 moves to the side, the side top block 11 moves to the side accordingly. The front end of the connection port cooperates with the side top block 11 to facilitate the stable lateral movement of the side top block 11. After the side top block 11 moves to the side, it pushes against the side wall of the fork arm workpiece 5 to limit the lateral movement of the fork arm workpiece 5.

[0021] The end clamping part includes three rectangular positioning pads 17 fixed to the right side of the upper wall of the bridge plate 2 near the through opening 3, which are used in conjunction with the lateral positioning base 10; a pressing screw 18 threaded to the center end wall of the positioning pad 17; a stop rod 19 threaded to the front side of the positioning pad 17 near the pressing screw 18; a matching seat 24 fixed to the rear side of the positioning pad 17 near the pressing screw 18; a pressure plate 21 connected to the top of the pressing screw 18 via a screw seat; a spring 20 arranged between the pressure plate 21 and the positioning pad 17 and sleeved on the outside of the pressing screw 18; and a positioning head 25 fixed to the bottom end of the pressure plate 21 and the top end wall of the matching seat 24. The stop rod 19 and the pressing screw 18 can both be threadedly driven with the positioning pad 17 to adjust the height of the stop rod 19 and the pressing screw 18. The top end of the stop rod 19 is threaded with a screw seat. The top end of the stop rod 19 is embedded in the bottom channel 23 of the pressure plate 21. The screw seat contacts and supports the bottom wall of the pressure plate 21, which facilitates the support of the pressure plate 21. At the same time, the pressure screw 18 directly passes into the notch 22 of the pressure plate 21 and is movably connected to the pressure plate 21 through the notch 22. A screw seat is threaded at the top end of the pressure screw 18. The screw seat is pressed against the upper wall of the pressure plate 21, pressing the pressure plate 21 downward. At the same time, the spring 20 is sleeved on the outside of the pressure screw 18. The top of the spring abuts against the pressure plate 21 and the bottom of the spring abuts against the positioning pad 17. This gives the pressure plate 21 a certain elasticity and buffer when it moves downward as the pressure screw 18 or the screw seat threaded at the end of the pressure screw 18 is tightened. This serves the purpose of simply protecting the fork arm workpiece 5. The positioning head 25 is used for point contact with the fork arm workpiece 5. Simultaneously, an elliptical notch 22 for movable connection of the pressing screw 18 is passed through the center of the end wall of the pressure plate 21. A bottom channel 23 is opened on the bottom wall of the pressure plate 21 for embedding the top end of the movable connection stop rod 19. Meanwhile, three fixed seats 26, compatible with the lateral positioning base 10 and positioning pad 17, are fixedly connected to the right side of the upper wall of the bridge plate 2 near the through opening 3. The fixed seats 26 are rectangular, and a fixed head 27 for abutting against the side wall of the fork arm workpiece 5 is fixedly connected to the top side wall of the fixed seat 26. The positioning head 25 is a cylindrical fixed head 27 with a top surface area only one-twentieth that of the top area of ​​the fixed seat 24. The fixed head 27 contacts and clamps the fork arm workpiece 5, respectively pressing and limiting the upper and lower end faces of the fork arm workpiece 5. The contact between the fork arm workpiece 5 and the fixed head 27 is point contact, compared to… Compared to ordinary clamping components, such as the mounting base 24, clamping head, and clamping plate, the reduced area decreases the force-bearing area of ​​the reference, reducing the problem of the fork arm workpiece 5 tilting due to lateral force during clamping. Conventional tooling fixtures have a large contact area with the fork arm workpiece 5, but due to the deformation of the fork arm workpiece 5, the reference surface is uneven. When clamping at several positioning points, due to lateral force plus the deformation of the fork arm workpiece 5, the blank surface of the fork arm workpiece 5 at other positioning points will tilt up. Due to the uncontrolled deformation of the blank of the fork arm workpiece 5, the structural part of the fork arm workpiece 5 that is far away from the reference causes a significant deviation from the original position. The farther the distance, the greater the positional fluctuation, which poses a great hidden risk to subsequent processing. Point-contact clamping reduces the force-bearing area of ​​the reference and can greatly compensate for the impact caused by deformation.

[0022] In summary, this machining fixture, which can reduce blank deformation, should be used as follows: The side connecting plate 1 is connected to the spindle box of the lathe. The bridge plate 2 inside the side connecting plate 1 is connected and fixed by bolts, which makes it convenient for the lathe to drive the bridge plate 2 synchronously to cooperate with the tools on the lathe for processing. The end wall of the bridge plate 2 is fixed to the positioning plate 4 by a threaded connection limiting screw 7. The plug-in screw 6 arranged at the positioning plate 4 is used to fit the fork arm workpiece 5 arranged in the forward direction. The pressure plate 8 covers the upper wall of the fork arm workpiece 5 arranged in the forward direction. The fixing nut 9 is tightened to press and limit the fork arm workpiece 5 arranged in the forward direction, which facilitates the processing of the structure of the fork arm workpiece 5 in the forward direction. The through-hole 3 of the bridge plate 2 is used to arrange the reverse-positioned fork arm workpiece 5, so that the protruding part of the reverse-positioned fork arm workpiece 5 can be accommodated in the through-hole 3, which facilitates the reverse-positioning of the fork arm workpiece 5. When arranged in reverse, the bottom wall of the fork arm workpiece 5 is supported by the positioning heads 25 of the three mounting seats 24 respectively, and the top wall is pressed and limited by the positioning head 25 at the bottom wall of the pressure plate 21, with point contact limit to prevent the fork arm workpiece 5 from tilting. When arranged in reverse, the side wall of the fork arm workpiece 5 is pressed and limited by three fixed heads 27 and three lateral top blocks 11, so that the fork arm workpiece 5 is stably limited and convenient for subsequent processing. When the handwheel 14 rotates, the lever 15 and the lateral positioning base 10 undergo threaded transmission. After lateral movement, the end of the lateral top block 11 is pressed against the side wall of the fork arm workpiece 5. The position of the lateral top block 11 is adjusted to better contact and press against the fork arm workpiece 5. The fixing head 27 at the fixing seat 26 is fixed in position and is used to cooperate with the lateral top block 11 to press against the fork arm workpiece 5. The lever nut 16 is tightened to reinforce and limit the position of the lever 15 after adjustment. When the pressure screw 18 or the screw seat rotates and moves downward, it drives the pressure plate 21 to move downward, causing the positioning head 25 at the end wall of the pressure plate 21 to move downward and press against the upper wall of the fork arm workpiece 5, which facilitates the stable positioning of the fork arm workpiece 5. The fixed position setting of the matching seat 24 is used to cooperate with the pressure plate 21 to press the fork arm workpiece 5. The setting of the spring 20 makes the pressure plate 21 have buffering properties when moving downward, making it more gentle.

[0023] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A machining fixture for reducing blank deformation, comprising a pair of side connecting plates (1) mounted on the headstock of a lathe and a rectangular bridge plate (2) supported at the end of the side connecting plates (1), characterized in that: The bridge plate (2) has a vertical clamping part on the left side of the upper wall and an end clamping part on the right side of the upper wall. Both the vertical clamping part and the end clamping part are used to clamp the fork arm workpiece (5). The vertical clamping part is used to clamp the fork arm workpiece (5) in the forward direction, and the end clamping part is used to clamp the fork arm workpiece (5) in the reverse direction. The end clamping part and the fork arm workpiece (5) are clamped by multiple points of contact.

2. The machining fixture for reducing blank deformation according to claim 1, characterized in that: The side connecting plate (1) is L-shaped and a supporting bridge plate (2) is mounted at the bottom L-shaped opening. The bridge plate (2) and the side connecting plate (1) are fastened together by bolts. A pair of through holes (3) are passed through the right end wall of the bridge plate (2).

3. The machining fixture for reducing blank deformation according to claim 2, characterized in that: A rectangular positioning plate (4) is fixed to the left side of the upper wall of the bridge plate (2) by a screw assembly. The vertical clamping part is located on the positioning plate (4). The screw assembly is a limiting screw (7), and there are four limiting screws (7).

4. The machining fixture for reducing blank deformation according to claim 3, characterized in that: The vertical clamping part includes a plug-in screw (6) vertically threaded at the center end wall of the positioning plate (4), a C-shaped pressure plate (8) sleeved on the outside of the plug-in screw (6), and a fixing nut (9) threaded at the top end of the plug-in screw (6) for pressing the pressure plate (8).

5. The machining fixture for reducing blank deformation according to claim 4, characterized in that: The plug screw (6) has flat end walls on both sides of the middle section, and the pressing plate (8) has an elliptical opening through the right wall at the center. The elliptical opening is roughly circular near the center.

6. The machining fixture for reducing blank deformation according to claim 5, characterized in that: A rectangular lateral positioning base (10) is fixed to the right side of the upper wall of the bridge plate (2) near the through opening (3). A connection port is horizontally penetrating the top of the lateral positioning base (10). A lateral top block (11) is movably arranged inside the connection port. A concave slot (12) in the shape of a concave character is penetrating the right wall of the lateral top block (11). A rod head (13) that is wider on the left and narrower on the right is rotatably connected at the concave slot (12).

7. The machining fixture for reducing blank deformation according to claim 6, characterized in that: The front end of the connection port is rectangular and the rear end is threaded. The front end of the connection port is used to arrange the lateral top block (11) and the rear end is used to thread the hand rod (15) to be fixed to the rod head (13). The hand wheel (14) is fixed to the end wall of the hand rod (15) away from the rod head (13). The rod nut (16) is threaded to the outside of the hand rod (15). There are three lateral positioning bases (10), lateral top blocks (11), rod head (13), hand wheel (14), hand rod (15), and rod nut (16).

8. The machining fixture for reducing blank deformation according to claim 7, characterized in that: The end clamping part includes three rectangular positioning pads (17) fixed to the right side of the upper wall of the bridge plate (2) near the through opening (3) and used in conjunction with the lateral positioning base (10); a pressing screw (18) threaded to the center end wall of the positioning pad (17); a stop rod (19) threaded to the front side of the positioning pad (17) near the pressing screw (18); a matching seat (24) fixed to the rear side of the positioning pad (17) near the pressing screw (18); a pressure plate (21) connected to the top of the pressing screw (18) via a screw seat; a spring (20) arranged between the pressure plate (21) and the positioning pad (17) and sleeved on the outside of the pressing screw (18); and a positioning head (25) fixed to the bottom end of the pressure plate (21) and the top end wall of the matching seat (24).

9. A machining fixture for reducing blank deformation according to claim 8, characterized in that: The positioning head (25) is used to make point contact with the fork arm workpiece (5). At the same time, an elliptical notch (22) for movably connecting the pressure screw (18) is passed through the center of the end wall of the pressure plate (21). A bottom channel (23) is opened on the bottom wall of the pressure plate (21) for embedding the top head of the movable connecting stop rod (19). At the same time, three fixed seats (26) that are compatible with the lateral positioning base (10) and the positioning pad (17) are fixedly connected to the right side of the upper wall of the bridge plate (2) near the through opening (3). The fixed seats (26) are rectangular. A fixed head (27) for abutting against the side wall of the fork arm workpiece (5) is fixedly connected to the top side wall of the fixed seat (26).

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