In the process of shearing plates using ordinary shearing machines, the company's material handling personnel have always relied on manual feeding and measurement positioning, which is very inefficient and sometimes results in incorrect part dimensions due to inaccurate measurements. After years of observation and research, the author invented an automatic positioning and feeding device that solves the above problems, reduces the labor intensity of operators, and improves the efficiency of shearing narrow plates.
1. Composition and Principle of Automatic Feeding and Positioning Device
The device is shown in Figure 1. The application process is as follows: ① Rotate the lead screw to adjust the positioning plate to the left of the upper blade holder, ensuring it equals the length of the cut piece (L). ② Place the sheet metal onto the roller on the support, so that it rests against the positioning plate. ③ Start the shearing machine, allowing the upper blade holder to descend and begin shearing.
Figure 1 Automatic feeding device for shearing machine
1. Positioning plate 2. Locking nut 3. Lead screw 4. Pull plate 5. Upper tool holder
6. Crank arm; 7. Lower tool holder; 8, 11, 18 , 31. Pin; 9. Sheet metal.
10, 20. Chain; 12. Guide rail; 13. Rack and pinion.
14, 15, 16, 19, 23 , 24. Gears; 17, 22. Sprockets
21. Roller 25. Bearing 26. Pawl 27. Spring 28. Pin 29. Bracket 30. Swing arm
Principle: When the upper blade holder drives the scissors downward to start cutting the plate, the crank arm fastened to the upper blade holder also moves downward synchronously, and pushes the left end of the swing arm downward through the pin 31. At this time, the right end of the swing arm will swing upward, and the pin 11 will move the rack upward along the vertical groove of the guide rail. The gear 14 meshing with it will rotate clockwise. The inner cavity of the gear 15 that meshes with it is a ratchet structure. At this time, although the gear 14 rotates, the gear 15 does not rotate. When the upper blade holder moves upward after shearing the sheet, the left end of the swing arm also moves upward along with the crank arm. At this time, the right end of the swing arm swings downward, and pin 11 moves the rack downward along the vertical groove of the guide rail. The gear 14 meshing with it rotates counterclockwise. Gear 15 rotates counterclockwise synchronously under the action of the pawl of gear 14, and drives gear 23 meshing with it to rotate clockwise. Gear 24, which is coaxial with it, also rotates clockwise and drives gear 16 to rotate counterclockwise. At this time, the sprocket mounted on the roller will rotate synchronously and drive the roller to rotate counterclockwise. Other rollers will rotate counterclockwise under the drive of the chain, causing the sheet placed on them to be fed to the left. When the left end of the sheet hits the positioning plate, the sheet will stop moving. At this time, the roller will continue to rotate counterclockwise as the upper blade holder continues to move upward, and sliding friction will occur between it and the sheet until the upper blade holder stops moving upward. When the upper blade holder moves the shear downward again, the above actions will be repeated.
The focus is on the swing arm shown in Figure 2. Both ends must have elongated slots to allow for the free up-and-down movement of pins 31 and 11 within the slots during swinging. The right end of the swing arm must be an integer multiple of the left end to extend the rack's stroke, increase the rotation speed of gear 14, and thus increase the feed size of the sheet metal. The bracket and swing arm have multiple sets of coaxial holes, allowing adjustment of the mounting pin 8 position according to the size of the sheet metal being sheared.
Figure 2 Swing Arm
The pull plate and lead screw are both two pieces, welded together at the rear of the shearing machine. The positioning plate is a single piece, with holes that are simultaneously installed on both lead screws. The positioning plate must have a certain degree of elasticity to facilitate proper positioning and repositioning during the shearing process.
2. Application Precautions
During use, the moving parts must be lubricated frequently; however, it is not suitable for feeding large plates. To ensure that the plate hits the positioning plate before shearing, the adjustment of pin 8 must be carefully considered. The roller must rotate more than half a turn when the plate hits the positioning plate. During the shearing process, pay attention to the condition of the plate to prevent uneven feeding caused by different friction on both sides due to warping. This would result in the plate not hitting the positioning plate completely on both sides, causing the sheared part to be tilted.
3. Conclusion
The automatic feeding and positioning device of this shearing machine solves the problems of manual feeding and piece-by-piece measurement and correction in ordinary shearing machines, which not only improves work efficiency but also ensures shearing quality, making it highly worthy of promotion.
