GB803669A - Improvements in or relating to power operated presses - Google Patents

Abstract

803,669. Trimming. NATIONAL RESEARCH DEVELOPMENT CORPORATION. Sept. 14, 1956 [Sept. 23, 1955], No. 27175/55. Class 83 (4). In a press having a trimming punch and die set, the ram is vibrated during the working stroke. The ram is vibrated by an electric motor and is moved through its working and return strokes by a double-acting piston-andcylinder. The moving part of the press, Figs. 1 and 2, is supported by pillars 6 slidably mounted in the bed 1. A cross-piece 7 connecting the lower ends of the pillars 6 is attached by linkage 9 to a double-acting pneumatic cylinder 16. A dead-weight 34 mounted on a cross-head 8 joining the upper end of the pillars 6 carries an electric motor 30 which, through a belt 27, drives a shaft 24 journalled transversely in the cross-head 8. A slipper 43, Fig. 4, mounted on a central eccentric portion of the shaft 24 serves to reciprocate rapidly the ram 22 through about twenty-thousandths of an inch. A punch secured to the ram 22 co-operates with a die mounted on a bolster 5 which may be adjustable vertically by means of a wedge 76. The upper limit of the stroke is determined by an adjustable stop 87 secured to the bed 1 and engaging the cross-piece 7. The lower limit of the working stroke is determined by engagement of shoulders 73 on the pillars 6 with split collars 74 on the bed 1 and surrounded by grease-retaining sleeves 77. The split collars are replaceable by others of different thicknesses. Dampers 90 are connected by linkage to the cross-piece 7 and the speed of the working stroke is limited by exhausting the lower chamber of the cylinder 16 through a throttle valve. A rod-like ejector 85 may be connected to the cross-piece 7. The cylinder 16 and so the operation of the press is controlled by the lowering of a guard 54 which actuates a micro-switch 64. In a modification the moving part of the press is carried by a single pillar slidably mounted in a part of the press-frame that overhangs the work-table. The Specification refers to a known trimming press in which the ram is vibrated during the working stroke by an eccentric driven by an electric motor, and the main stroke of the ram is effected by a cam driven by an electric motor and bearing upon the centre knuckle joint of a toggle lever system connected between the frame and the ram of the press.