GB1242259A - Improvements in or relating to compacting machines - Google Patents

Abstract

1,242,259. Moulding powders. BIRMING- HAM SMALL ARMS CO. Ltd. 2 Jan., 1970 [13 Dec., 1968], No. 59300/68. Heading B5A. A machine for the production of compacts of metal or other powder having two or more sections of different thickness in the line of pressure includes an upper punch 7 fixed to a ram of the machine, an axially movable die 1 defining the outer periphery of the compact, a fixed lower punch 3 and a vertically movable punch 2 disposed within the die, the punch 2 being movable from an upper pre-compacting position to a lower final position, and being supported by a piston 8 within a stationary cylinder 9 and slidable about the punch 3. An axially adjustable core rod 4 is provided. The piston 8 is held in its uppermost position by pressure fluid in the chamber 11 and the face 12 of the cylinder defines the lowermost position of the piston forced down during compaction. The movement of the piston 8 and punch 2 may be assisted by fluid pressure applied to the upper face of a shoulder 13 by means of a piston 18 in a cylinder 17 and forced down by a plunger 21 connected to the ram 20. A resilient buffer 22 is located between the parts 21 and 23. The area of piston 18 is less than that of the shoulder 13 and initially the piston 8 moves slower than the ram 20; as the powder is compressed between the punches 2 and 7 both move at the same speed and the buffer 22 expands. Alternatively, the fluid pressure on the piston 8 is applied from a separate source controlled by a valve operated by the ram movement. In a further embodiment initial movement of the punch 2 causes the piston 8 to move downwardly exposing a shoulder thereof to high pressure fluid; alternatively high pressure fluid may be applied to the said shoulder without the initial downward movement by the punch.