GB597115A - Improvements in presses for the extrusion of lead and lead alloys - Google Patents

Abstract

597,115. Extruding. BRITISH INSULATED CALLENDER'S CABLES, Ltd., and SPENCER, J. A. Aug. 10, 1945, No. 20533. [Class 83 (iv)] In a press for the extrusion of lead and lead alloys, comprising a ram working through one end of a container to extrude through a die at the other end, the molten metal enters the container from a vessel at a higher level through a port in the container wall, the opening and closing of the port being effected by a power actuated valve which keeps the port closed during the extrusion stroke. The container 1 is mounted on a die box supported on a fixed base and the ram 3 is operated hydraulically. Molten metal from a vessel 43 passes by way of a heated pipe 26 to a metal block 20 bolted to the wall of the container. The passage of the metal from the pipe 26 into the container is controlled by a rod 17 passing through a bore in the block 20 and through a port 14 in the container and operated by a hydraulic cylinder 37. The inner portion 16 of the port 14 is of smaller diameter and the two portions are connected by a taper portion 15 against which the conical end 18 of the rod 17 is adapted to seat to close the port. In this closed position, the end of the rod is flush with the inner surface of the container so that only a thin wall of solid metal can obstruct the inner end of the port when the rod is withdrawn to admit a new charge. Bolted to the block 20, but separated from it by an insulating layer, is a water-cooled casing 27 formed with longitudinally spaced annular grooves 30 adapted to fill with solidified metal which acts as a seal or gland. The block 20 is kept heated by a burner 34. The lowermost position of the ram is indicated by the line 48. In order to increase the rate of cooling of a new charge prior to the next extrusion stroke, the ram is formed with a central tapering opening so as to leave an upstanding column 50 of solid metal on its upward stroke and the port 14 is offset from the radial position so that the entering metal is given a circulatory motion around the column. To speed up the operation still further, the stroke of the ram may be shortened and its lower end provided with grooves adapted to fill with solidified metal to form a packing.