(19)

(11)

EP 0 629 283 A1

(12)

(43) Date of publication: 21.12.1994 Bulletin 1994/51 (21) Application number: 93905506.0 (22) Date of filing: 04.03.1993

(51) International Patent Classification (IPC):  G01C 9/ 06( . ) G01C 9/ 34( . ) (86) International application number: PCT/GB1993/000448 (87) International publication number: WO 1993/018370 (16.09.1993 Gazette 1993/22)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB IE IT LI LU NL PT SE (30) Priority: 07.03.1992 GB 19920005027 (71) Applicant: TURNER INTELLECTUAL PROPERTY LIMITED Burton-on-trent, Staffs DE14 1SD (GB)	(72) Inventors: HEPWORTH, Paul Steabben Guildford, Surrey GU1 3TP (GB) BROOKS, Brian Edward Burton-on-Trent, Staffordshire DE13 0LD (GB) (74) Representative: Mosey, Stephen George  MARKS & CLERK Alpha Tower Suffolk Street Queensway Birmingham B1 1TT Birmingham B1 1TT (GB)