(19)

(11)

EP 0 453 494 A1

(12)

(43) Date of publication: 30.10.1991 Bulletin 1991/44 (21) Application number: 90902299.0 (22) Date of filing: 11.01.1990

(51) International Patent Classification (IPC):  A01B 51/ 02( . ) (86) International application number: PCT/GB1990/000039 (87) International publication number: WO 1990/007866 (26.07.1990 Gazette 1990/17)

(84) Designated Contracting States: DE DK ES FR GB IT NL SE (30) Priority: 11.01.1989 GB 19890000564 12.01.1989 GB 19890000676 (71) Applicant: DOWLER GANTRY SYSTEMS LIMITED Warwick CV35 OPL (GB)	(72) Inventors: DOWLER, David Warwick CV35 0PL (GB) WATTS, Laurence, George Warwickshire CV3 6FU (GB) WILSON, David, John Peterborough PE6 8HD (GB) (74) Representative: Adkins, Michael  4 Dyer's Buildings Holborn London EC1N 2JT London EC1N 2JT (GB)