GB383556A - Improvement in duplex hydraulic broaching machine - Google Patents

Abstract

383,556. Broaching. LAPOINTE MACHINE TOOL CO., 34, Tower Street. Hudson, Massachusetts, U.S.A. May 11, 1932, No. 13563. Convention date, May 19, 1931. [Class 83 (iii).] A hydraulically operated broaching machine has two broaching members, the return stroke of one member being made at a high speed during the first part of the working stroke of the other members; means comprising a dual capacity pump are provided for operating the machine at different speeds. The pump P, Fig. 1, has small and large output sections 92, 93, connected by pipes 95, 102 to the casing of a manually operable valve V<1>, shown in Fig. 5 in its neutral position for byepassing the output of both pump sections. The valve may be moved into either of three other positions so that the output of either or both pump sections may be delivered at will to a passage 115 leading to the casing of a reversing valve V, Fig. 14, which controls the distribution of liquid to the ends of the cylinders 42, 52, the position of the valve being determined by cam members 24, 25, Fig. 2, on the broaching heads A, B. The broaching heads are connected by hollow rods 43, 53 to pistons 41, 51, working over fixed pipes 44, 54 ported at 48, 58, and connected by a passage 60, to which the cylinders are connected under the control of check valves 63, 64. When the valve V is in the position shown in Fig. 14, pressure liquid causes the piston 41 to start its working stroke, the displaced liquid passing to the pipe 54 to effect the rapid return stroke of the piston 51 ; when said return is completed, liquid passes from the pipe 54 through the port 58. A tank T for the reception and delivery of liquid as required is connected in the circuit under the control of pressure-operated valves 72, 73.