(19)

(11)

EP 0 224 488 A1

(12)

(43) Date of publication: 10.06.1987 Bulletin 1987/24 (21) Application number: 85904337.0 (22) Date of filing: 19.08.1985

(51) International Patent Classification (IPC):  H03K 7/ 08( . ) (86) International application number: PCT/US1985/001572 (87) International publication number: WO 1986/007509 (18.12.1986 Gazette 1986/27)

(84) Designated Contracting States: BE DE FR GB (30) Priority: 05.06.1985 US 19850741509 (71) Applicant: CATERPILLAR INC. Peoria Illinois 61629-6490 (US)	(72) Inventor: HOFFMAN, John, P. Peoria, IL 61606 (US) (74) Representative: Brunner, Michael John, et al  GILL JENNINGS & EVERY Broadgate House 7 Eldon Street London EC2M 7LH London EC2M 7LH (GB)