(19)

(11)

EP 0 528 843 A1

(12)

(43) Date of publication: 03.03.1993 Bulletin 1993/09 (21) Application number: 91908517.0 (22) Date of filing: 16.04.1991

(51) International Patent Classification (IPC):  E01C 23/ 09( . ) E01F 9/ 06( . ) E01C 23/ 18( . ) E01F 9/ 07( . ) (86) International application number: PCT/GB1991/000595 (87) International publication number: WO 1991/016499 (31.10.1991 Gazette 1991/25)

(84) Designated Contracting States: AT DE DK ES FR GB IT NL SE (30) Priority: 20.04.1990 GB 19900008886 (71) Applicants: SHERWIN, Godfrey, Peter Aylesbury, Bucks HP17 0QQ (GB) SHERWIN, Gillian Aylesbury, Bucks HP17 0QQ (GB)	(72) Inventors: SHERWIN, Godfrey, Peter Aylesbury, Bucks HP17 0QQ (GB) SHERWIN, Gillian Aylesbury, Bucks HP17 0QQ (GB) (74) Representative: Gibson, Stewart Harry  URQUHART-DYKES & LORD, Three Trinity Court, 21-27 Newport Road Cardiff CF2 1AA Cardiff CF2 1AA (GB)