(19)

(11)

EP 0 541 555 A1

(12)

(43) Date of publication: 19.05.1993 Bulletin 1993/20 (21) Application number: 91909044.0 (22) Date of filing: 09.05.1991

(51) International Patent Classification (IPC):  G08B 13/ 196( . ) (86) International application number: PCT/GB1991/000738 (87) International publication number: WO 1991/017532 (14.11.1991 Gazette 1991/26)

(84) Designated Contracting States: GB (30) Priority: 09.05.1990 GB 19900010348 (71) Applicant: DIXEY, Terence Gray Leeds LS8 3DP (GB)	(72) Inventor: WESTON, Dennis Leeds LS7 4HN (GB) (74) Representative: Harrison, Michael Robert  Dibb Lupton Broomhead 117 The Headrow Leeds LS1 5JX West Yorkshire Leeds LS1 5JX West Yorkshire (GB)