GB1399597A - Drawing die assemblies - Google Patents

Abstract

1399597 Drawing; stamping P M ROSS 14 June 1972 [24 June 1971] 29648/71 Headings B3P and B3Q A metal drawing die assembly, e.g. for drawing metal tubes and containers using a mandrel, comprises a frusto-conical or right cylindrical die 12 axially immovably retained within a surrounding holder 13 and means for applying adjustable forces to the outer surface of the die 12 to elastically compress or expand the die 12 so as to vary the size of the die opening 11. In one embodiment, Fig. 1, the die 12 which is secured by a locking ring 14 in a collar 13, is stressed so as to alter the size of its opening 11 by feeding oil under pressure into an annular space 16 surrounding the die 12. A larger annular space 16 may be formed by using a flared ring (21) (Fig. 3, not shown) positioned between the die 12 and collar 13. In another embodiment, Fig. 6A, the die 12F is surrounded by rollers 30 and a split ring 13F whose ends may be urged towards each other to compress the die 12F by a piston-rod 34 of an hydraulic ram 35. Alternatively, the die is stressed by segments (23), (Fig. 4B, not shown), each forced into engagement with the die by an hydraulic ram (22) mounted in a collar (13D). In a further embodiment (Fig. 2, not shown), the outer surface of the die (12B) and the bore of the collar (13B) are frusto-conical. In another embodiment (Fig. 5, not shown), the die (12E) is tightly fitted on a collar (13E) which can be cooled or heated by circulating fluid through a jacket (24).