(19)

(11)

EP 0 493 430 A1

(12)

(43) Date of publication: 08.07.1992 Bulletin 1992/28 (21) Application number: 90913724.0 (22) Date of filing: 06.09.1990

(51) International Patent Classification (IPC):  B21B 13/ 06( . ) B21B 31/ 20( . ) B21B 31/ 18( . ) (86) International application number: PCT/GB1990/001376 (87) International publication number: WO 1991/004106 (04.04.1991 Gazette 1991/08)

(84) Designated Contracting States: BE DE FR GB IT NL (30) Priority: 12.09.1989 GB 19890020641 (71) Applicant: DAVY McKEE (SHEFFIELD) LIMITED Sheffield S9 4EX Yorkshire (GB)	(72) Inventors: GRONBECH, Robert, William Sheffield Yorkshire S9 4EX (GB) Lister, Michael Sheffield Yorkshire S13 8LF (GB) (74) Representative: Kirk, Geoffrey Thomas, et al  BATCHELLOR, KIRK & CO. 2 Pear Tree Court Farringdon Road London EC1R 0DS London EC1R 0DS (GB)