GB1128285A - A punching machine - Google Patents

Abstract

1,128,285. Punching. OSTERWALDER A.G. 21 Feb., 1967 [8 March, 1966], No. 8193/67. Heading B3W. A punching machine comprises a pair of relatively movable tool support members adapted to close on one another to effect a punching operation therebetween with one said member moving the other member through a limited distance to a punching position, wherein each member has an associated control element adapted to operate on respective machine control circuit elements when the respective member attains a predetermined position during movement of the members towards the punching position, the sequence of operation of the control circuit elements governing further operation of the machine. The punch 9 is mounted in a plate 3, supported in turn by a sleeve 4 which rests on a cushion of oil 6. The position of the punch is adjusted by spacing rings 7a. The die plate 2a is secured to a bearer plate 2 which has a recess 23 in its upper surface to receive the flanged end 21 of a tubular member 12 which is fixed in the yoke 11 of the press. The flange 21 is retained in the recess by a cover-plate 24, and four springs 25 balance the weight of the bearer plate 2, which can move vertically through the distance 26. A piston 15 attached to a tubular piston-rod 14 is slidable in a cylinder formed by an enlargement of the bore 13, the upper end of which is closed by a cap 17. A quantity of pressurized oil 18 fills the space above the piston. A rod 19 passes through the rod 14 and at its lower end is connected to a bolt 20, the lower end of which projects from the undersurface of the flange 21. At the upper end of the rod 19 is a member 34 which actuates a switch 35. There is a clearance 27 between the piston-rod 14 and the bolt 20. A second switch 33 is actuated by a bolt 31 which passes through a bracket 30 secured to the plate 3. Operation.-With the plate 3 in its lowest position the switch 33 is closed by the screw 31, and opens as the plate moves upwards. The screw 31 is adjusted so that the switch 33 opens when the gap between the punching tools is equal to the thickness of the workpiece. The switch 35 is normally open and closes as the rod 19 is lifted by the plate 2, after the clearance 27 has been taken up. If there is an obstruction between the tools, then the switch 35 will close before the switch 33 opens, and with both switches closed, the machine control circuit is short-circuited and the machine stops.