Workpiece positioning structure of numerical control bending machine

Abstract

The utility model discloses a workpiece positioning structure of a numerical control bending machine, which belongs to the field of positioning structures and comprises a lower workbench, an upper workbench is arranged above the lower workbench, the top surface of the lower workbench is fixedly connected with a lower die, an arranged positioning mechanism is matched with an upper numerical control bending machine for use, and a workpiece to be bent is placed on the top surface of a supporting dragging table. A workpiece penetrates through the space between the lower die and the upper die, a rotating button is rotated to drive a two-way screw rod to rotate through a third rotating rod, and symmetrical L-shaped adjusting rods move relatively along the two-way screw rod through first screw holes in the side walls till positioning pressing rods are arranged on the two sides of the upper portion of the workpiece according to the width of the workpiece; and then a screw knob is rotated to drive a second connecting block to move downwards through the screw knob, and the second connecting block drives a positioning pressing rod to move downwards through a second sliding block, so that the positioning pressing rod is pressed on the two sides of the top surface of the workpiece, and the purpose of rapidly positioning and fixing the workpiece according to the sizes and thicknesses of different workpieces is achieved.

Description

Technical Field

[0001] This utility model relates to the field of positioning structures, and in particular to a workpiece positioning structure for a CNC bending machine. Background Technology

[0002] CNC bending machines use equipped molds (general or special molds) to bend cold metal sheets into workpieces of various geometric cross-sectional shapes. They are sheet metal forming machines designed for cold-rolled sheet metal processing and are widely used in sheet metal bending processes in industries such as automobiles, aircraft manufacturing, light industry, shipbuilding, containers, elevators, and railway vehicles.

[0003] In existing CNC bending machines, the operator places the workpiece between the lower and upper bending dies during operation. The operator must hold the workpiece against the positioning rod and hold the end of the workpiece while the upper bending die moves downward to bend it. During this downward movement, the operator's hand must continuously support the workpiece and work with the bending machine to lift it upward. Due to the lack of workpiece positioning measures and the operator's hand's instability during prolonged operation, manual positioning can lead to positional deviations, affecting bending accuracy. While some machines use positioning fixtures to fix the workpiece during bending, these fixtures only allow for the positioning of workpieces of the same size. For workpieces of different sizes, different fixtures must be used, making the operation cumbersome, reducing the practicality of the fixtures, and lowering work efficiency. Utility Model Content

[0004] The main purpose of this utility model is to provide a workpiece positioning structure for a CNC bending machine, which can effectively solve the problems in the background art.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A workpiece positioning structure for a CNC bending machine includes a lower worktable and an upper worktable above it. A lower die is fixedly connected to the top surface of the lower worktable. The upper worktable is fixedly connected to the output ends of two symmetrical hydraulic cylinders on both sides, and an upper die is fixedly connected to the bottom surface of the upper worktable. A positioning mechanism is provided at the front end of the lower worktable, and the positioning mechanism includes a support slide, a cylinder, a double-acting screw, an L-shaped adjusting rod, a positioning pressure rod, and a screw knob. The support slide is connected to the concave top of the front end of the lower worktable via a first rotating rod on the outer wall of the first connecting block on both rear sides. The cylinder is movably connected to the concave block at the front end of the lower worktable and the bottom of the support platform via the second rotating rods at both ends of the T-shaped connector at the bottom of the cylinder body and the top of the output end. The bidirectional screw is movably connected to the symmetrical fixed blocks at the front end of the support platform via the third rotating rods at both ends. The two L-shaped adjusting rods are movably connected to the bidirectional screw via the first screw hole on the side wall. The positioning pressure rod is movably connected to the rear wall of the L-shaped adjusting rod via the second slider at the front end. The screw knob is movably connected to the second connecting block at the front end of the second slider via the rotating block at the top end.

[0007] As a preferred embodiment of this utility model, a concave strip is fixedly installed on the top front end of the lower worktable, and a first rotating hole is opened on both sides of the inner wall of the concave groove of the concave strip. A set of left-right symmetrical first connecting blocks are fixedly installed on the rear wall of the support platform, and a first rotating rod is fixedly installed on the outer wall of the first connecting block and movably installed in the first rotating hole. A set of left-right symmetrical concave blocks are fixedly installed on the front wall of the lower worktable below the concave strip and on the front end of the bottom of the support platform, and a second rotating hole is opened on both sides of the inner wall of the concave groove of the concave block. A T-shaped connector is fixedly installed on the bottom end of the cylinder body and the top end of the output end of the cylinder, and a second rotating rod is fixedly installed on both ends of the transverse part of the T-shaped connector and movably installed in the second rotating hole.

[0008] As a preferred technical solution of this utility model, a set of left-right symmetrical fixing blocks are fixedly installed on the front wall of the support platform, and a third rotating hole is opened on the side wall of the fixing block. A sliding groove is also opened on the front wall of the support platform between the fixing blocks.

[0009] As a preferred embodiment of this utility model, a third rotating rod is fixedly installed at each of the left and right ends of the bidirectional screw, and the third rotating rod is movably installed in the third rotating hole. A rotary knob is fixedly installed at the outer end of the third rotating rod. A set of L-shaped adjusting rods is provided symmetrically on the left and right sides. A first screw hole is opened at the lower side wall of the vertical part of the L-shaped adjusting rod and is threadedly connected to the bidirectional screw through the first screw hole. A first slider is also fixedly installed at the lower rear end wall of the vertical part of the L-shaped adjusting rod, and the first slider is movably installed in the slide groove.

[0010] As a preferred technical solution of this utility model, a vertical sliding opening is provided on the front wall of the vertical part of the L-shaped adjusting rod, and a second screw hole is provided on the top surface of the horizontal part of the L-shaped adjusting rod. The screw knob is threadedly connected to the second screw hole, and a rotating block is fixedly installed on the top of the screw knob.

[0011] As a preferred technical solution of this utility model, a second slider is fixedly installed on the front wall of the positioning pressure rod, and the second slider is movably installed in the vertical sliding opening. A second connecting block is fixedly installed at the front end of the second slider, and a groove is fixedly installed on the bottom surface of the second connecting block. The rotating block is movably installed in the groove.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] In this invention, the positioning mechanism, in conjunction with a CNC bending machine, places the workpiece to be bent on the top surface of the support table, allowing the workpiece to pass between the lower and upper dies. Rotating the knob drives the bidirectional screw to rotate via the third rotating rod, causing the symmetrical L-shaped adjusting rods to move relative to each other through the first screw holes on the side walls along the bidirectional screw until the positioning pressure rods are positioned on both sides above the workpiece according to its width. Then, rotating the screw knob moves the second connecting block downwards, and the second connecting block, through the second slider, moves the positioning pressure rods downwards, pressing them firmly against both sides of the workpiece's top surface. This achieves rapid bending of the workpiece according to its size and thickness. The purpose of positioning and fixing is to allow the cylinder to tilt upwards during the bending process, as it is in a movable installation state. This tilting action allows the support platform to support and lift the workpiece as it changes position after bending, ensuring effective bending. The positioning mechanism replaces manual workpiece positioning and lifting, effectively preventing workpiece displacement during prolonged operation. It is simple and convenient to operate, reduces worker workload, and improves the mechanism's practicality. It not only ensures accurate workpiece bending but also increases work efficiency. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0015] Figure 2 This is a schematic diagram of the overall structure of the positioning mechanism of this utility model;

[0016] Figure 3 For the present utility model Figure 2 A magnified diagram showing the partial structure at point A;

[0017] Figure 4This is a schematic diagram of the overall structure of the support platform of this utility model;

[0018] Figure 5 For the present utility model Figure 3 A magnified diagram showing the structural breakdown at point B.

[0019] In the diagram: 1. Lower worktable; 2. Lower mold; 3. Hydraulic cylinder; 4. Upper worktable; 5. Upper mold; 6. Positioning mechanism; 7. Concave strip; 8. First rotating hole; 9. Concave block; 10. Second rotating hole; 11. Support platform; 12. First connecting block; 13. First rotating rod; 14. Cylinder; 15. T-shaped connector; 16. Second rotating rod; 17. Fixing block; 18. Third rotating hole; 19. Slide groove; 20. Bidirectional screw; 21. Third rotating rod; 22. Rotary knob; 23. L-shaped adjusting rod; 24. First screw hole; 25. First slider; 26. Vertical slide opening; 27. Second screw hole; 28. Positioning pressure rod; 29. ​​Second slider; 30. Second connecting block; 31. Protrusion; 32. Screw knob; 33. Rotating block. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] like Figure 1 - Figure 5As shown, a workpiece positioning structure for a CNC bending machine includes a lower worktable 1, with an upper worktable 4 above it. A lower die 2 is fixedly connected to the top surface of the lower worktable 1. The upper worktable 4 is fixedly connected to the output ends of two symmetrical hydraulic cylinders 3 on both sides, and an upper die 5 is fixedly connected to the bottom surface of the upper worktable 4. A positioning mechanism 6 is provided at the front end of the lower worktable 1. The positioning mechanism 6 includes a support slide 11, a cylinder 14, a bidirectional screw 20, an L-shaped adjusting rod 23, a positioning pressure rod 28, and a screw knob 32. The support slide 11 is movably connected to the concave strip 7 at the top front end of the lower worktable 1 via a first rotating rod 13 on the outer wall of the first connecting blocks 12 on both sides of the rear end. The cylinder 14 is movably connected between the front end of the lower worktable 1 and the concave block 9 on the bottom surface of the support platform 11 via the second rotating rods 16 at both ends of the T-shaped connector 15 at the bottom of the cylinder body and the top of the output end. The bidirectional screw 20 is movably connected between the symmetrical fixed blocks 17 at the front end of the support platform 11 via the third rotating rods 21 at both ends. The two L-shaped adjusting rods 23 are movably connected to the bidirectional screw 20 via the first screw hole 24 on the side wall. The positioning pressure rod 28 is movably connected to the rear wall of the L-shaped adjusting rod 23 via the second slider 29 at the front end. The screw knob 32 is movably connected to the second connecting block 30 at the front end of the second slider 29 via the rotating block 33 at the top end.

[0022] like Figure 2 and Figure 3 As shown, a concave strip 7 is fixedly installed on the top front end of the lower worktable 1, and a first rotating hole 8 is opened on both sides of the inner wall of the concave groove of the concave strip 7. A set of left-right symmetrical first connecting blocks 12 are fixedly installed on the rear wall of the support platform 11, and a first rotating rod 13 is fixedly installed on the outer wall of the first connecting block 12 and movably installed in the first rotating hole 8. A set of left-right symmetrical concave blocks 9 are fixedly installed on the front wall of the lower worktable 1, below the concave strip 7, and on the front end of the bottom of the support platform 11, and a second rotating hole 10 is opened on both sides of the inner wall of the concave groove of the concave block 9. A T-shaped connector 15 is fixedly installed on the bottom end of the cylinder body and the top end of the output end of the cylinder 14, and a second rotating rod 10 is fixedly installed on both ends of the horizontal part of the T-shaped connector 15. 6. The second rotating rods 16 at both ends of the horizontal part of the T-shaped connector 15 at the bottom of the cylinder body and the top of the output end of the cylinder 14 are respectively movably installed in the second rotating holes 10 on both sides of the concave inner wall of the concave block 9 on the bottom surface of the lower worktable 1 and the support tray 11. Therefore, when the cylinder 14 drives the output end, it will tilt and push the support tray 11 upward. The first rotating rods 13 on the outer side of the first connecting block 12 on both sides of the rear end wall of the support tray 11 will rotate in the first rotating holes 8 on both sides of the concave inner wall of the concave strip 7. This allows the support tray 11 to tilt according to the degree of end warping of the workpiece during bending, and to support and lift the workpiece under the premise of positioning it, so as to ensure the effective bending of the workpiece.

[0023] like Figure 3 and Figure 4 As shown, a set of left-right symmetrical fixing blocks 17 are also fixedly installed on the front wall of the support platform 11, and a third rotating hole 18 is provided on the side wall of the fixing block 17. The third rotating hole 18 is used to cooperate with the third rotating rod 21 to realize the rotation operation. A sliding groove 19 is also provided on the front wall of the support platform 11 and between the fixing blocks 17. The sliding groove 19 is used to cooperate with the first slider 25 to realize the sliding operation.

[0024] like Figure 2 and Figure 5 As shown, a third rotating rod 21 is fixedly installed at both ends of the bidirectional screw 20, and the third rotating rod 21 is movably installed in the third rotating hole 18. A rotary knob 22 is fixedly installed at the outer end of the third rotating rod 21. A set of L-shaped adjusting rods 23 are provided symmetrically on the left and right sides, and a first screw hole 24 is opened on the lower side wall of the vertical part of the L-shaped adjusting rod 23, and it is threadedly connected to the bidirectional screw 20 through the first screw hole 24. A first slider 25 is also fixedly installed on the lower rear end wall of the vertical part of the L-shaped adjusting rod 23. The movable part is installed in the slide groove 19. Rotating the rotary knob 22 can drive the third rotating rod 21 to rotate in the third rotating hole 18, so that the third rotating rod 21 drives the bidirectional screw 20 to rotate. This allows the symmetrical L-shaped adjusting rods 23 to move in opposite directions along the bidirectional screw 20 through the first screw hole 24 opened below the side wall of the vertical part, and the first slider 25 slides in the slide groove 19. In this way, the position of the positioning pressure rod 28 can be adjusted according to the size and width of the workpiece until the positioning pressure rod 28 is positioned on the left and right sides above the workpiece.

[0025] like Figure 2 and Figure 5 As shown, a vertical sliding opening 26 is provided on the front wall of the vertical part of the L-shaped adjusting rod 23, and a second screw hole 27 is provided on the top surface of the horizontal part of the L-shaped adjusting rod 23. The screw knob 32 is threadedly connected to the second screw hole 27, and a rotating block 33 is fixedly installed on the top of the screw knob 32. Rotating the screw knob 32 in the second screw hole 27 can cause the screw knob 32 to rotate downward and move. The screw knob 32 can drive the rotating block 33 to rotate synchronously and move downward. The vertical sliding opening 26 is used to cooperate with the second slider 29 to realize the sliding operation.

[0026] like Figure 2 and Figure 5As shown, a second slider 29 is fixedly installed on the front wall of the positioning pressure rod 28, and the second slider 29 is movably installed in the vertical sliding opening 26. A second connecting block 30 is fixedly installed at the front end of the second slider 29, and a protrusion 31 is fixedly installed on the bottom surface of the second connecting block 30. A rotating block 33 is movably installed in the protrusion 31. Because the rotating block 33 is restricted to being installed in the protrusion 31, when the rotating block 33 moves downward, it will synchronously drive the second connecting block 30 to move downward. The second connecting block 30 will drive the second slider 29 to slide in the vertical sliding opening 26. The second slider 29 will drive the positioning pressure rod 28 to move downward until the positioning pressure rod 28 is pressed against both sides of the top surface of the workpiece. In this way, the workpiece can be pressed and fixed on the top surface of the support table 11 according to the thickness of the workpiece, so as to prevent the workpiece from shifting when bending the workpiece.

[0027] The specific operating principle of the positioning mechanism 6 in conjunction with the CNC bending machine is as follows:

[0028] Place the workpiece to be bent on the top surface of the support table 11, allowing it to pass between the lower die 2 and the upper die 5 and abut against the positioning rod. Rotate the knob 22 located on the front side of the support table 11. Rotating the knob 22 will cause the third rotating rod 21 to rotate within the third rotating hole 18 on the side wall of the fixed block 17. The third rotating rod 21 will then cause the bidirectional screw 20 to rotate, causing the left and right symmetrical L-shaped adjusting rods 23 to move relative to each other through the first screw hole 24 below the vertical side wall along the bidirectional screw 20. After continuously rotating the knob 22 to move the L-shaped adjusting rods 23 relative to each other, position the positioning pressure rod 28 on the rear end wall of the vertical part of the L-shaped adjusting rod 23 on the left and right sides above the workpiece. Then rotate the knob 22 located on the front side of the support table 11. The screw knob 32 on the bottom surface of the horizontal part of the L-shaped adjusting rod 23 rotates in the second screw hole 27 on the bottom surface of the horizontal part of the L-shaped adjusting rod 23. It drives the rotating block 33 installed at the top to rotate in the groove 31 on the bottom surface of the second connecting block 30. After the screw knob 32 is continuously rotated, the screw knob 32 will drive the second connecting block 30 to move downward through the rotating block 33 at the top. The second connecting block 30 will drive the second slider 29 to slide in the vertical sliding mouth 26 on the front wall of the vertical part of the L-shaped adjusting rod 23. The second slider 29 drives the positioning pressure rod 28 to move downward continuously until the positioning pressure rod 28 is pressed against both sides of the top surface of the workpiece. In this way, the workpiece can be positioned and fixed on the top surface of the support table 11.

[0029] It should be further explained that the positioning rod 28 can also be moved downwards to contact the top surface of the support table 11 but not pressed against it. Then, the L-shaped adjusting rod 23 can be moved relative to the positioning rod 28, so that the L-shaped adjusting rod 23 drives the positioning rod 28 to move relative to each other synchronously. In this way, the workpiece can be positioned, centered and clamped between the positioning rods 28. After the positioning rod 28 is moved upwards, the symmetrical positioning rods 28 can be moved relative to each other and moved to the two sides above the workpiece. Finally, the positioning rod 28 can be moved downwards to position and press the workpiece firmly and fix it on the top surface of the support table 11.

[0030] After the workpiece is positioned, pressed, and fixed, the hydraulic cylinder 3 is activated to drive the upper worktable 4 to move downwards. Once the upper die 5 on the bottom surface of the upper worktable 4 contacts the top surface of the workpiece, it will press the workpiece downwards. In conjunction with the lower die 2 installed on the top surface of the upper and lower worktables 1, the workpiece can be bent into a specified shape. During the bending process, the workpiece is positioned, pressed, and fixed on the bottom surface of the support tray 11, so there will be no displacement of the workpiece. At the same time, because the second rotating rods 16 at both ends of the horizontal part of the T-shaped connector 15 at the bottom of the cylinder body of the cylinder 14 and the top of the output end are respectively movably installed in the second rotating holes 10 opened on both sides of the concave inner wall of the concave block 9 on the bottom surface of the lower worktable 1, when the cylinder 14 drives the output end, it will tilt and push the support tray 11 upwards. The first rotating rods 13 on the outer side of the first connecting block 12 on both sides of the rear end wall of the support tray 11 will be in the concave strip 7 The workpiece rotates through the first rotating holes 8 on both sides of the inner wall of the recess, allowing the support platform 11 to tilt according to the degree of end-to-end tilting during bending. This provides support and lift for the workpiece while maintaining its position, ensuring effective bending. After bending, the cylinder 14 is activated again to reset the support platform 11, releasing the positioning and clamping mechanism. The bent workpiece can then be removed from the top surface of the support platform 11. Thus, the positioning mechanism 6 achieves rapid positioning and fixing of workpieces according to their size and thickness, replacing manual workpiece positioning and lifting. During extended operation, it effectively prevents workpiece displacement during bending. The operation is simple and convenient, reducing labor intensity and improving the mechanism's practicality. It not only ensures the accuracy of workpiece bending but also increases work efficiency.

[0031] It should be noted that, in this document, terms such as "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0032] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A workpiece positioning structure of numerical control bending machine, comprising a lower worktable (1), and an upper worktable (4) is arranged above the lower worktable (1), a lower die (2) is fixedly connected to the top surface of the lower worktable (1), the output end of two symmetric oil cylinders (3) is fixedly connected with the upper worktable (4), and an upper die (5) is fixedly connected to the bottom surface of the upper worktable (4), characterized in that: The front end of the lower workbench (1) is provided with a positioning mechanism (6), and the positioning mechanism (6) comprises a supporting drag table (11), a gas cylinder (14), a bidirectional screw rod (20), an L-shaped adjusting rod (23), a positioning pressing rod (28) and a screw knob (32), the supporting drag table (11) is movably connected with the concave strip (7) at the top of the front end of the lower workbench (1) through the first rotating rod (13) on the outer side wall of the first connecting block (12) at the both sides of the rear end, and the gas cylinder (14) is movably connected between the front end of the lower workbench (1) and the concave block (9) on the bottom surface of the supporting drag table (11) through the second rotating rod (16) at both ends of the T-shaped connecting head (15) at the bottom end and the top end of the output end of the cylinder body, the bidirectional screw rod (20) is movably connected between the fixed blocks (17) symmetrically arranged at the front end of the supporting drag table (11) through the third rotating rod (21) at both ends, and the two L-shaped adjusting rods (23) are movably connected with the bidirectional screw rod (20) through the first screw holes (24) in the side walls, respectively, the positioning pressing rod (28) is movably connected to the rear wall of the L-shaped adjusting rod (23) through the second sliding block (29) at the front end, and the screw knob (32) is movably connected with the second connecting block (30) at the front end of the second sliding block (29) through the rotating block (33) at the top end.

2. A workpiece positioning structure for a CNC press brake as set forth in claim 1, characterized in that: The front end of the lower workbench (1) is provided with a positioning mechanism (6), and the positioning mechanism (6) comprises a supporting drag table (11), a gas cylinder (14), a bidirectional screw rod (20), an L-shaped adjusting rod (23), a positioning pressing rod (28) and a screw knob (32), the supporting drag table (11) is movably connected with the concave strip (7) at the top of the front end of the lower workbench (1) through the first rotating rod (13) on the outer side wall of the first connecting block (12) at the both sides of the rear end, and the gas cylinder (14) is movably connected between the front end of the lower workbench (1) and the concave block (9) on the bottom surface of the supporting drag table (11) through the second rotating rod (16) at both ends of the T-shaped connecting head (15) at the bottom end and the top end of the output end of the cylinder body, the bidirectional screw rod (20) is movably connected between the fixed blocks (17) symmetrically arranged at the front end of the supporting drag table (11) through the third rotating rod (21) at both ends, and the two L-shaped adjusting rods (23) are movably connected with the bidirectional screw rod (20) through the first screw holes (24) in the side walls, respectively, the positioning pressing rod (28) is movably connected to the rear wall of the L-shaped adjusting rod (23) through the second sliding block (29) at the front end, and the screw knob (32) is movably connected with the second connecting block (30) at the front end of the second sliding block (29) through the rotating block (33) at the top end.

3. A workpiece positioning structure for a CNC press brake as set forth in claim 2, wherein: The front end wall of the supporting drag table (11) is also provided with a group of left-right symmetrical fixed blocks (17), and the side wall of the fixed block (17) is provided with a third rotating hole (18), and the front end wall of the supporting drag table (11) and between the fixed blocks (17) is also provided with a sliding groove (19).

4. A workpiece positioning structure for a CNC press brake as set forth in claim 3, characterized in that: The left and right ends of the bidirectional screw rod (20) are respectively fixedly provided with third rotating rods (21), and the third rotating rods (21) are movably arranged in the third rotating holes (18), the outer ends of the third rotating rods (21) are fixedly provided with rotating knobs (22), the L-shaped adjusting rods (23) are symmetrically arranged in pairs, the vertical part side walls of the L-shaped adjusting rods (23) are provided with first screw holes (24) below, and the L-shaped adjusting rods (23) are screwed with the bidirectional screw rod (20) through the first screw holes (24), the vertical part rear end walls of the L-shaped adjusting rods (23) are further fixedly provided with first sliding blocks (25), and the first sliding blocks (25) are movably arranged in the sliding grooves (19).

5. A workpiece positioning structure for a CNC press brake as set forth in claim 4, characterized in that: The vertical part front end walls of the L-shaped adjusting rods (23) are further provided with vertical sliding openings (26), the horizontal part top surfaces of the L-shaped adjusting rods (23) are provided with second screw holes (27), the screw rod knobs (32) are screwed with the second screw holes (27), and the top ends of the screw rod knobs (32) are fixedly provided with rotating blocks (33).

6. A workpiece positioning structure for a CNC press brake as set forth in claim 5, characterized in that: The front end walls of the positioning pressing rods (28) are fixedly provided with second sliding blocks (29), the second sliding blocks (29) are movably arranged in the vertical sliding openings (26), the front ends of the second sliding blocks (29) are fixedly provided with second connecting blocks (30), the bottom surfaces of the second connecting blocks (30) are fixedly provided with convex grooves (31), and the rotating blocks (33) are movably arranged in the convex grooves (31).

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