GB911508A - Improvements in or relating to hydraulic ram equipment for draw-benches and the like - Google Patents

Abstract

911,508. Drawing. NATIONAL RESEARCH DEVELOPMENT CORPORATION. March 20, 1961 [March 18, 1960], No. 9587/60. Class 83 (4). In an hydraulically-operated drawbench there are two fixed rams with tail rods which are anchored at one end to the stationary frame of the bench and a twin cylinder assembly that is movable lengthwise with respect to the rams and their tail rods and which includes a crosshead for one or more draw rods at its end near the tail rod anchorage, the rams themselves being guided on the frame beyond the other end of the cylinder assembly. The machine comprises an anchor member 4 for the tail rods 13, connected by girders 5 to a guide member 1 for the rams 11. Also mounted on the girders 5 is a draw-plate 2 for dies 3. Between each ram and tail rod is mounted a floating piston 17 (see Specification 911,507). The twin-cylinder assembly comprises two cylinders 12 connected at one end by a crosshead 9, which carries gripping jaws 8, and in which are stuffing-boxes 10, and at the other end by a member 19 in which there are stuffing-boxes 18. When pressure fluid is admitted to the space between the pistons 17 and the crosshead 9 the cylinder assembly moves to the right in Fig. 1 and draws the work through the dies 3. A guide 7 for use in wire drawing is provided in the member 1, and for tube drawing the guide is replaced by a plug rod. In a modification, Fig. 6, the rams 22. and tail rods 27 are connected by pistons 23 which are a close fit in the cylinders 24 and each ram 22 comprises two coaxial tubes 25 and 26. For the working stroke pressure fluid is supplied to the inner tubes 26 by a connection 50 and passes through a passage 49 to the spaces to the right of the pistons 23, and for the return stroke fluid is supplied to connections 47 and passes by passages 48 to the spaces to the left of the pistons 23.