PUNCHING DEVICE OF PLATE MATERIAL HAVING CLEAT

PURPOSE:To reduce a deformation in the vertical longitudinal direction of a sectional shape and a section of a feed cleat in case of punching a plate material by providing a projection in the vicinity of a punching hole of a die, holding a hole punched before by this projection, and executing the punching. CONSTITUTION:When a punch plate 11 ascends, the first punching hole of a plate material 10 is fitted to a projection 16b of a die 16. When the punch plate 11 descends, a stripper 14 hits against the plate material 10, and subsequently, a punch 12 goes into the plate material 10. In this case, a lateral pressure (f) following the punching is generated, and a feed cleat of the plate material tries to escape and hits against the projection 16b of the die 16. However, since a gradient of the projection 16b and a gradient of the side face of the feed cleat hitting part are the same, there is no gap between the projection 16b and the side face of the feed cleat, and the feed cleat cannot escape. When the plate material 10 is punched and the punch 12 goes into the die 16, the descent of the punch 12 is stopped. This device displays an effect for improving the accuracy of an electronic accelerating material, etc. of a lead frame of an IC and a cathode ray tube of a video apparatus.