| 摘要 |
1,167,433. Stamping. ETS CL. JACQUEMARD. 10 April, 1967 [14 April, 1966], No. 16262/67. Heading B3Q. A press for cold forming sheet components A under hydraulic pressure comprises a die 26, 27, 28 at the upper end of a set of toggle links 5, a ram 9 mounted on the upper end of a second set of toggle links 11, and a cam 20 displaceable to compensate for changes in workpiece volume, the links 5, 11 being straight by the end of the stroke of the ram 9 when a further ram 2, controlled by the energy-source previously used to operate the links, effects high-pressure calibration of the workpiece. The links 5, 11 and the cam 20 are operated hydraulically, by cylinders 8, 17, 21. The die includes a lower section 28 attached to the ram 9, a divided upper section 26 suspended from a cylinder 18 and a bevel-ring 27 for closing the section 26. A table 4 for operating the ring 27 is carried by the links 5 and may also raise the plunger 9, by its top flange. At each side of the ram 9, on its support 10, is an abutment 23 for operating pistons in cylinders 22. A nut 16 in a fixed table 3 adjusts the links 11 and thus the stroke of the ram 9. Operation.-After filling the workpiece with a liquid, e.g. water, cylinder 8 is operated for raising table 4, to close the die-section 26, and for raising the ram by its top flange. When the top links 5 are in a straight, locking condition, pressure in cylinder 8 increases, and a valve directs oil to the cylinders 17, which filled as the ram was raised by the top links 5. The cylinders 17 now develop the forming pressure on the ram, and at this stage the abutments 23 engage the pistons in cylinders 22 for supplying the cylinder 21 and displacing the cam 20. A piston 19 operated by the cam, controls the volume of water in the workpiece during the forming operation. Abutment between the die sections 26, 28 terminates the ram-stroke when the links 11 are straight. The oil in cylinders 17 now communicates with a cylinder 24 to increase the fluid pressure in the blank, by means of a plunger 25. In a modification, cylinder 21 is operated by a pump which is regulated by a pickup controlled by the ram 9 over the final part of its stroke. |
