(19)

(11)

EP 0 629 259 A1

(12)

(43) Date of publication: 21.12.1994 Bulletin 1994/51 (21) Application number: 93906918.0 (22) Date of filing: 09.02.1993

(51) International Patent Classification (IPC):  E21B 7/ 20( . ) E21B 33/ 10( . ) E21B 17/ 14( . ) E21B 33/ 12( . ) (86) International application number: PCT/SE1993/000089 (87) International publication number: WO 1993/018274 (16.09.1993 Gazette 1993/22)

(84) Designated Contracting States: AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE (30) Priority: 09.03.1992 SE 19920000730 (71) Applicants: ALEXANDERSSON, Hans S-513 00 Fristad (SE) NELSON, Anders S-420 17 Södra Sandby (DE)	(72) Inventors: ALEXANDERSSON, Hans S-513 00 Fristad (SE) NELSON, Anders S-420 17 Södra Sandby (DE) (74) Representative: Ferkinghoff, Claes-Göran, et al  AWAPATENT AB, Södra Hamngatan 37-41, P.O. Box 11394 S-404 28 Göteborg S-404 28 Göteborg (SE)