(19)

(11)

EP 0 239 578 A1

(12)

(43) Date of publication: 07.10.1987 Bulletin 1987/41 (21) Application number: 86904278.0 (22) Date of filing: 08.07.1986

(51) International Patent Classification (IPC):  G10H 1/ 34( . ) (86) International application number: PCT/GB1986/000393 (87) International publication number: WO 1987/000330 (15.01.1987 Gazette 1987/01)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 09.07.1985 GB 19850017306 03.12.1985 GB 19850029718 (71) Applicant: STEPP LIMITED London NW1 8YL (GB)	(72) Inventors: RYAN, Paul Over, Cambridge (GB) MASSEY, David Huntingdon Cambridgeshire (GB) (74) Representative: Cross, Rupert Edward Blount, et al  BOULT, WADE & TENNANT 27 Furnival Street London EC4A 1PQ London EC4A 1PQ (GB)