(19)

(11)

EP 0 121 537 A1

(12)

(43) Date of publication: 17.10.1984 Bulletin 1984/42 (21) Application number: 83903151.0 (22) Date of filing: 05.10.1983

(51) International Patent Classification (IPC):  G11B 20/ 24( . ) (86) International application number: PCT/AU1983/000141 (87) International publication number: WO 1984/001656 (26.04.1984 Gazette 1984/11)

(84) Designated Contracting States: BE CH DE FR GB LI NL SE (30) Priority: 07.10.1982 AU 19820006232 (71) Applicant: THE COMMONWEALTH OF AUSTRALIA Canberra, Australian Capital Territory 2600 (AU)	(72) Inventor: HAMILTON, Neil, Robert Werribee, VIC 3030 (AU)