(19)

(11)

EP 0 031 333 A1

(12)

(43) Date of publication: 08.07.1981 Bulletin 1981/27 (21) Application number: 80901134.0 (22) Date of filing: 03.07.1980

(51) International Patent Classification (IPC):  E04H 4/ 06( . ) (86) International application number: PCT/GB1980/000114 (87) International publication number: WO 1981/000129 (22.01.1981 Gazette 1981/02)

(84) Designated Contracting States: AT CH DE FR GB LI LU NL SE (30) Priority: 03.07.1979 GB 19790023135 (71) Applicant: C.J. KIRK (ENGINEERING) LIMITED Berkshire RG11 6DP (GB)	(72) Inventor: KIRK, Colin John Crowthorne Berkshire RG11 6DP (GB) (74) Representative: Sheader, Brian N.  Eric Potter & Clarkson St. Mary's Court St. Mary's Gate Nottingham NG1 1LE Nottingham NG1 1LE (GB)