(19)

(11)

EP 0 250 489 A1

(12)

(43) Date of publication: 07.01.1988 Bulletin 1988/01 (21) Application number: 87900031.0 (22) Date of filing: 24.12.1986

(51) International Patent Classification (IPC):  E01F 9/ 011( . ) E01F 9/ 017( . ) (86) International application number: PCT/AU1986/000395 (87) International publication number: WO 1987/003921 (02.07.1987 Gazette 1987/14)

(84) Designated Contracting States: AT BE CH DE FR GB IT LI LU NL SE (30) Priority: 24.12.1985 AU 19850004025 (71) Applicant: BUILTRITE PRODUCTIONS PTY. LIMITED Greenacre, NSW 2190 (AU)	(72) Inventor: NG, Eric North Strathfield, NSW 2137 (AU)