| 摘要 |
993,100. Extruding plastic material. BAROGENICS Inc. Nov. 8, 1963 [Nov. 9, 1962], No. 44186/63. Heading B5A. [Also in Division B3] A workpiece 45 is deformed by fluid pressure acting directly or indirectly on the workpiece by first pressurizing the fluid to a primary pressure and then applying a transient secondary pressure produced by a shock wave to initiate the deformation. In an hydrostatic extrusion apparatus as described in Specification 942,642, a billet 45 surrounded by hydraulic fluid 46 is enclosed in a chamber 12 closed by a ram 35 carrying one or more extrusion dies 70, 71. The ram is moved upwardly to apply primary pressure to fluid 46, by a piston 25 in cylinder 17 supplied with hydraulic fluid through port 31. Secondary pressure to initiate extrusion is applied by a shock wave produced by a high-voltage discharge across electrodes 90, 91 connected to capacitors 102, transformer 103 and rectifier 104. The electrodes may alternatively be provided below piston 25 in cylinder 17. In another embodiment, Fig. 4, the billet 130 is extruded directly through die 126 by ram 135 connected to hydraulic piston 136. Primary fluid pressure is produced in chamber 137 by an hydraulic pump acting through conduit 140. The secondary pressure is produced by an explosive charge 145 detonated by a battery 151. Alternatively a thin wire may be exploded by a high-current pulse. U.S.A. Specification 3,063,594 also is referred to. |
