Patent GB-1089344-A (GB)
Title: Improvements in or relating to high energy rate forming machines
IPC: B21C23/18
Filed: 1964-11-16
Abstract: 1,089,344. Metal working presses. J. K. MUREK. Nov. 16, 1964 [Dec. 30, 1963], No. 46495/64. Heading B3H. A high-velocity forming machine comprises a ram 96 driven by a pressure chamber 98, a bolster 22 driven by a pressure chamber 60, means for securing and rapidly releasing the ram and bolster for movement towards each other to form a workpiece 122. Between the head 90 and base 12 of the machine are four guide rods 14 passing through the bolster 22 and also guiding a carriage (20, Fig. 1) which forms a guide for a rectangular extension 100 of the ram, carries latches 160 for locking the ram in its raised position (Fig. 2), and has a pair of cylindrical extensions 130 forming cylinders 134. Extending from the bolster is a ram 56 in the chamber 60 which is preferably formed in a lower ram adjustable in a cylinder 26 for positioning the bolster. Hydraulic fluid is fed to cylinders 26, 134 and gas, e.g. air, to cylinders 98, 60. Tubes 38 passing through the bolster, supply the fluid to cylinders 134 under the control of electrically-operated valves 32. Operation.-With the parts in the cocked position (Fig. 2) hydraulic pressure is admitted above the pistons 150 in locking cylinders 148 mounted on the carriage. This turns locking levers 140 about pivots 138, releasing the latches 160 and freeing the ram 96. The levers 140 operate switches 166 for actuating the valves 32 to reduce the pressure in the cylinders 134 and another valve for relieving the pressure above pistons 150. The ram and bolster are now free to form the work. It is stated that because upward movements of the bolster along tubes 38 increase the volume of cylinders 134, sub-atmospheric pressures are developed in these cylinders. This effect and that of hydraulic fluid in the cylinder 50, is said to increase the kinetic energy of the bolster. At the end of the forming stroke (Fig. 4) the force generated by the bolster cylinder 60 overcomes that of the ram cylinder 98 and returns the ram to its raised position where it is locked by the latches 160, preferably assisted by a small pressure beneath the latching pistons 150. Switches 170 operated by the levers 140 now re-set the valves 32 for pressurizing cylinders 134 and lowering the platen to its cocked position ready for another working stroke. An hydraulic ejector (70, Fig. 2) is housed within the platen. It is stated that the machine would operate without switches 166, or if they failed or the valves failed to relieve the pressure in the cylinders 134, because after the latches 160 have been released the carriage 20 rises with the bolster 22, increasing the volume of cylinders 134 and lowering their pressure to subatmospheric level. If this mode of operation is intended, a limit switch 172 is operated by the bolster in its lower cocked position to close the valves 32 and retain the liquid in cylinders 134. Alternative operation.-If the cylinder 60 is not pressurized, the bolster will remain stationary, except for shock-absorbing movements if gas is introduced with the hydraulic fluid in cylinder 50. Successive sections of'long members may be formed in this manner. In a modification without guide rods (Figs. 8 and 9) the carriage (186) and bolster (190) are guided in adjustable jibs (210, 204) within an outer frame (176).