GB660257A - Improvements in and relating to the extrusion of materials such as metals - Google Patents

Abstract

660,257. Extruding. GENDERS, R., and ROWLES, R. V. Jan. 16, 1949 [Jan. 14, 1948; June 29, 1948], Nos. 1109/48 and 17459/48. Class 83 (iv). An extrusion press comprises a container, a die, one hydraulic ram for forcing the billet through the die, a second hydraulic ram for moving the container and control means for the rams so that during the extrusion operation the container may be stationary, moving with the speed of the extrusion ram or moving at a lower speed. The ram 1 operating through a cross-head 5 under the action of a hydraulic cylinder 2 carries a thrust-rod 7 for applying pressure to the billet 9 within a container 8. The extrusion die 11 is mounted at the end of a tubular holder 12 carried by a housing 14. The container is supported by two piston-rods 16, 17 extending at each end into cylinders 18, 19 and 20, 21, respectively, which may be connected to exhaust or to a supply of pressure fluid in order to control the position and movement of the container. An ordinary extrusion occurs if the ram is operated to force the billet through the die while the container is stationary. By allowing the container to move at the speed of the rain, thus avoiding friction between the billet and container, lower extrusion pressures may be used, but the finish of the product is said to be not as good. Preferably the container moves with the ram at the beginning and end of the operation but is stationary for the greater part of the operation. Or, if desired, the container may move during the whole period but at a speed lower than that of the ram. In a modified form of apparatus the container is supported by piston-rods extending from the housing 14 only and at the end where the pressure-rod 7 enters, is abutted by a ram concentric with the main extrusion ram but controlled independently therefrom.