Patent ID: 8714065
Filing Date: 2014-05-06
Classification: B21D,B26D,Y10T

Abstract:
1. A punch tool, including a blade part having a rectangular cross section to form a slit and a slot along a longitudinal direction of the blade part onto a sheet-like workpiece by nibbling process, the punch tool comprising: a cylindrical punch guide having, on its lower side, a stripper part which presses a periphery of the part to be processed in the workpiece, the stripper part having an insertion hole provided therein; a punch body including a main body, the punch body being movably provided in the vertical directions in a punch guide and has, on a lower side of the punch body, the blade part that is configured for insertion into the insertion hole; a punch head provided at an upper end of the punch body; a body cap provided between the punch head and an upper end of the main body of the punch body, wherein the upper end of the main body of the punch body is screw-fitted to a screw-fitting part inside of the body cap; a stripper spring which is provided on a lower side of the punch head and which is configured to bias the punch body; a first rotation control module configured to control rotation of the punch body with respect to the punch guide, the first rotation control module including: a first key groove configured to vertically extend in the punch guide; and a first key provided in the main body of the punch body located on a left side of the main body with respect to the longitudinal direction of the blade part, the first key movably fitted in the vertical direction to the first key groove; and a second rotation control module configured to control rotation of the punch body with respect to the punch guide, the second rotation control module including: a second key groove configured to vertically extend in the punch guide; and a second key provided in the main body of the punch body located on a right side of the main body with respect to the longitudinal direction of the blade part, the second key being movably fitted in the vertical direction to the second key groove; wherein the first key extends in the radial direction of the punch body; and wherein the first and second rotation control modules are configured to be symmetrical with respect to the longitudinal direction of the blade part of the punch body and respectively located on the left and right sides of the main body with respect to the longitudinal direction of the blade part of the punch body, such that when the punch body is displaced in the circumferential direction around the vicinity of the first rotation control module during the nibbling process, the second rotation control module suppresses the displacement, and when the punch body is displaced in the circumferential direction around the vicinity of the second rotation control module during the nibbling process, the first rotation control module suppresses rattling between the punch body and the punch guide due to the displacement by the nibbling process, thereby eliminating steps in a punched surface of the sheet like workpiece.