A punching die element for use in the punching of rectangular holes in punching cards, and a punching die made from such elements

摘要

927,784. Punching dies. V. F. SORENSEN. March 8, 1962 [March 13, 1961], No. 8974/62. Class 31 (2). [Also in Group XXII] A punching die element for punching rectangular holes in cards comprises a plurality of first steel bars of rectangular cross-section placed side by side to form a grid, a plurality of parallel grooves extending transversely across at least one face of said bars, and a second steel bar pressed into each of said grooves, the adjoining faces of the bars being surface ground in a common grinding operation. Steel bars 1 are assembled with spacers 2 and clamped by bolts 3, or are assembled in a jig. Grooves 4 are machined to a predetermined depth across the bars and further bars 5 are press fitted into the grooves. The upper surface of the assembly is then finished by grinding to form a cutting plate. A punch guide plate is made by assembling two elements so that the faces in which the holes 6 occur are remote from one another. In a modification, where the distance between the holes is considerable, two thin bars are used to define the ends of each hole, instead of a single thick bar. The guide plate may consist of first bars 1 with second bars 5 fitted into both faces.