Patent GB-987999-A (GB)
Title: Improvements in pressure fluid-operated apparatus for the shaping of work-pieces
IPC: B21J9/12
Filed: 1962-01-17
Abstract: 987,999. Forging. MASCHINENFABRIK HASENCLEVER A.G. Jan. 17, 1962 [Jan. 19, 1961; July 28, 1961], No. 1735/62. Heading B3H. [Also in Division B5] In a fluid operated machine which may be operated as a hammer or press, a column of fluid of relatively small cross-section is accelerated to impart to a fluid column of relatively large cross-section a reduced acceleration, the energy of the large liquid column being used to deform a workpiece. The fluid may be oil or any other suitable liquid, or it may be air, and more than two columns may be used. In a first embodiment, a press frame 1 carries a work head 3 in the form of a hollow piston sliding in a cylinder 2. A second hollow piston 7 slides in the piston 3, is guided by a tube 10 attached to a press frame extension 12, and carries a weight 8. A separate hydraulic piston 15 and cylinder 16 attached to the press frame returns the hollow piston 3 to its uppermost position. Operation as a hammer.-Valve 34 is opened, thus allowing fluid to pass from cylinder 16 through conduit 23, flow regulating valve 33, valve 34 and conduit 38 to cylinder 2. Thus the hold-up pressure in cylinder 16 is released and piston 3 commences to fall, and with it the piston 7 and weight 8. As the piston 3 falls, pressure in cylinder 2 will decrease and hence the pressure within piston 3 due to the piston 7 and weight 8 will cause fluid to flow from within piston 3 to cylinder 2 via a valve 4 in the piston 3. Hence, the piston 7 will descend faster than piston 3. When a tool carried on the piston 3 strikes a workpiece, the kinetic energy of piston 7 and weight 8 will be converted into pressure energy which will be transmitted to the workpiece by oil being forced at high pressure through the valve 4 to act on the piston 3. A spring- loaded fluid accumulator 5 may be used to limit the maximum pressure in the cylinder 32. Operation as a press.-Valve 26 is closed and fluid from the pump 17 is supplied through conduit 38 to the cylinder 2, thus driving the piston 3 downward. The piston 7, which was filled with fluid during a return stroke, will have no movement relative to the piston 3. In a second embodiment, Fig. 2, the mass which provides the accelerating force to the smaller of the two liquid columns of the embodiment shown in Fig. 1 is replaced by two horizontally opposed masses 46, 47 to which acceleration is imparted by the application of fluid pressure to pistons 50, 51 in cylinder 52. The fluid filled space between pistons 44, 45 carrying the weights 46, 47 is connected through a conduit 55 and valve 56 to the cylinder 39 which contains the tool carrying piston 40. A piston 41 is fixed in the cylinder 39 and acts as a guide for the piston 40. The piston 40 is raised by applying fluid pressure through the piston 41 to the interior of piston 40. The raising of the piston 40 causes the fluid above it to flow back through the valve 56, thus returning pistons 44, 45 and 48, 49 to their starting positions. To operate the machine as a press, valve 56 is closed and conduit 55 is connected to the pump 17 of Fig. 1. A third embodiment (Fig. 3, not shown), is very similar to that shown in Fig. 1 except that two retraction cylinders are employed and their associated piston-rods apply compressive force to the top of the main piston, which extends upwards from the top of the main cylinder. The conduit connecting the two liquid columns is also modified. The pressure fluid control system, Fig. 1, comprises a motor 24 driving a pressure pump 17 and a leakage pump 18, the latter being connected to various leakage wells indicated by 37. Relief valves 19, 20 which are set to the maximum pressure necessary to support the pistons in their uppermost position, are located respectively in a conduit 21 connecting the return pump 18 to the guide tube 10, and in conduit 23. 25 is a two-way, and 26, 27, 28 are on/off, solenoid-operated valves. An overflow valve 29 is controlled by the weight 8. 30 indicates a combined throttle and check valve and 31 is a combined throttle and pressure setting valve. 32 is a check valve and 33 is an adjustable throttling valve. 34 is an hydraulically operated two-way valve, and two spring-loaded accumulators 35, 36 are provided, the latter having an adjustable threshold pressure.