GB739291A - Improvements in gripping devices for sheet metal stretching machines - Google Patents

Abstract

739,291. Stretching; work-holders. BIGWOOD & SON, Ltd., J. May 3, 1954 [May 18, 1953], No. 13796/53. Classes 83 (3) and 83 (4). A sheet-metal stretching-machine, of the type having two gripping heads each comprising a pair of jaws 17 having opposed inwardly-converging surfaces 18 upon which are slidably mounted gripping-blocks 21 carrying the gripping members which engage the surfaces of the sheet 12, is characterized in that both the upper and lower gripping members each comprises a number of separate gripping- pieces 31 in end-to-end relationship across the width of the jaws, each gripping-piece 31 being rigidly secured to its own individual gripping- block 21 by one or more separate securing members 35 which engage the gripping-piece to hold it at positions spaced away from the operative surface 32 of the gripping-piece so that such surface is unbroken by holes. Each member 35 comprises a wedging-strip in a channel in the outer surface of a block 21 mating with an inclined face 34 along one edge of the gripping-piece 31 and secured to the block 21 by screws 36. The blocks 21 slide on rollers 22 over the converging surfaces 18 of the jaws and are guided and supported, at least for the upper jaw, by flanges 28 thereon sliding in channels 30 in the jaws. The jaws are opened and closed by a bar 37, which extends the width of the jaws, linked by adjustable spring-urged rods 38 to the blocks 21 and actuated by a piston 47 in a hydraulic or pneumatic cylinder. Specification 614,186 is referred to.