(19)

(11)

EP 0 888 510 A1

(12)

(43) Date of publication: 07.01.1999 Bulletin 1999/01 (21) Application number: 97917695.0 (22) Date of filing: 28.03.1997

(51) International Patent Classification (IPC):  G05D 16/ 06( . ) (86) International application number: PCT/US1997/005119 (87) International publication number: WO 1997/037162 (09.10.1997 Gazette 1997/43)

(84) Designated Contracting States: AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 29.03.1996 US 19960014290P (71) Applicant: S.H. Leggitt Company San Marcos, TX 78666 (US)	(72) Inventors: TURNEY, Christopher, G. San Marcos, TX 78666 (US) HEALD, Paul, W. San Marcos, TX 78666 (US) (74) Representative: Lupton, Frederick, et al  Kilburn & Strode, 20 Red Lion Street London WC1R 4PJ London WC1R 4PJ (GB)