GB1172821A - Improvements relating to Presses for Performing Blanking Drawing and Pressing on Strip Material. - Google Patents

Abstract

1,172,821. Punching; stamping. METAL CLOSURES GROUP Ltd. 2 Dec., 1966 [14 Sept., 1965], No. 39265/65. Headings B3Q and B3W. A method of punching blanks from a strip of sheet material comprises moving the strip lengthwise of itself and between successive movements of the strip, moving a punch and die assembly stepwise across the strip along a line which is inclined to the lengthwise dimension of the strip, and performing a punching operation between successive steps of the movement of the assembly across the strip. An apparatus for feeding a continuous strip of material to a punching press and for cutting up the resulting webbing includes a punch press 1 in which are mounted a punch assembly 6 and 7 and a die assembly 8. The punch assembly comprises a double-acting hydraulic ram 19 having a reduced end 20 to which is secured a plate 22 and a punch bolster 23. The punch 25 is retained by a holder 24 and passes through a stripper 26. The ram cylinder 12 is closed at its lower end by a slipper block 11 which slides on bars 10 attached to the side frames 2 of the press. The upper end of the cylinder engages guide bars 28, 28A. The die assembly comprises a die 16 and a bolster 14 which slides on guide rails 13. The punch and die assemblies are slidably connected by guide rods 9, Fig. 2 (not shown). The punch and die assemblies are moved stepwise along their guide rails by a pinion 47 which engages a rack on the underside of the bolster. The pinion is secured to a shaft (48), Fig. 5 (not shown), which is driven in opposite directions by rotary hydraulic actuators (49R and 49L) connected to opposite ends of the shaft by free-wheel clutches (50R and 50L). The strip 17 passes through tunnels 18, 18A through the press side frames. The length of the tunnel is at an angle of 65 degrees to the strip feed direction. The punching head is traversed across the strip by rotation of the pinion after each punching operation. After punching the hole at the edge of the strip the head remains stationary and the strip is moved forward to bring it to a position to punch the first hole of the next row. The punching head is then traversed stepwise in the opposite direction. The webbing remaining after the strip has been punched is cut after each forward movement of the strip by a reciprocating shear blade 35 co-operating with a stationary blade 34 and operated by a fluid cylinder 43. The strip feed mechanism comprises a pair of rolls (44), Fig. 5 (not shown), driven by a rotary hydraulic actuator (141) through a one-way clutch (147). The amount of feed is adjustable by a device (146). The valves controlling the punch ram, the punching head traverse, the feed rolls and the webbing shear are controlled by a cam-shaft (100) driven by a variable speed motor (101) so that the cycle of operations is continuously repeated. The operation of the punching head traversing mechanism is initiated by the return of the punch to its fully retracted position.