GB794339A - Improvements relating to impact extrusion presses - Google Patents

Abstract

794,339. Extruding. INNSWORTH METALS, Ltd., and DOWTY, G. H. July 5, 1955 [April 5, 1954], No. 9934/54. Class 83 (4). An impact extrusion press comprises a frame 11 having a fixed die support 16 and a movable ram carrier 17, a resilient telescopic device 22, 23 interposed between the press frame and the carrier 17, and power-operated mechanism 27 arranged to compress the resilient telescopic device and build-up stored energy therein which stored energy is released during extension of the resilient telescopic device to effect the extrusion operation. The resilient telescopic device is preferably a liquid spring comprising a cylinder 23 mounted on a transverse pin 24 in the press frame, and a plunger 22 connected to the extrusion ram carrier 17. The liquid spring is compressed by a pair of hydraulic jacks 27 disposed one on each side of the press and whose piston-rods 28 are each connected through a lost-motion connection 31, 34 to a bell-crank lever 33 pivoted at 32 to the press frame. The other arms of the bell-crank levers are connected at 35 to toggle links 36 connected to trunnions 37 extending from the carrier 17. When the jacks are operated, the toggle linkage 33, 36 is moved into in-line position, thus compressing the liquid spring, and after passing over the dead-centre position the liquid spring extends rapidly to effect the impact extrusion operation. The lost-motion connection 31, 34 permits the liquid spring to extend without affecting the hydraulic jacks, but the latter are then energzied to take-up the lost-motion and again compress the liquid spring whereby each stroke of the hydraulic jacks produces a compression of the liquid spring. The extrusion tools, Fig. 3, comprise a housing 44 secured to the die support 16 and adapted to receive a metal billet 54 and an extrusion ram 52 and mandrel 51 which are connected through an attachment plate 53 to the carrier 17. The extrusion die is provided on a spigot member 47 having an interrupted thread for rapid engagement in an interrupted threaded bore in the housing 44. The billet 54 is cold impact extruded between the mandrel 51 and the die to form a tube. The liquid spring 22, 23 is adjustable for controlling its rate of extension and hence the impact force. The press frame is built up of side-plates and base-plates.