(19)

(11)

EP 0 394 270 A1

(12)

(43) Date of publication: 31.10.1990 Bulletin 1990/44 (21) Application number: 88907149.0 (22) Date of filing: 18.07.1988

(51) International Patent Classification (IPC):  G09B 23/ 28( . ) (86) International application number: PCT/AU1988/000259 (87) International publication number: WO 1989/000416 (26.01.1989 Gazette 1989/03)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 17.07.1987 AU 19870003181 19.08.1987 AU 19870003831 (71) Applicants: BLAIR, Alan, James North Mackay, QLD 4740 (AU) BLAIR, Raewyn, Edith North Mackay, QLD 4740 (AU) SWANSON, John Lewis Mackay, QLD 4740 (AU) HARDY, Caterina, Vladimira Mackay, QLD 4740 (AU)	(72) Inventors: BLAIR Alan James North Mackay, QLD 4740 (AU) BLAIR Raewyn Edith North Mackay, QLD 4740 (AU) SWANSON John Lewis Mackay, QLD 4740 (AU) HARDY Caterina, Vladimira Mackay, QLD 4740 (AU) (74) Representative: Patentanwälte Wenzel & Kalkoff  Postfach 73 04 66, Grubesallee 26 D-22124 Hamburg D-22124 Hamburg (DE)