(19)

(11)

EP 1 268 971 A1

(12)

(43) Date of publication: 02.01.2003 Bulletin 2003/01 (21) Application number: 01917998.5 (22) Date of filing: 29.03.2001

(51) International Patent Classification (IPC)7: E21B 10/26 (86) International application number: PCT/NL0100/258 (87) International publication number: WO 0107/5261 (11.10.2001 Gazette 2001/41)

(84) Designated Contracting States: AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR Designated Extension States: AL LT LV MK RO SI (30) Priority: 31.03.2000 NL 1014813 (71) Applicant: Gebr. van Leeuwen Harmelen B.V. 3481 MC Harmelen (NL)	(72) Inventors: VAN LEEUWEN, Anton, Dirk NL-3481 LM Harmelen (NL) VAN LEEUWEN, Jan NL-3444 BE Woerden (NL) VAN DOORN, Gerrit NL-4184 CM Opijnen (NL) (74) Representative: Riemens, Roelof Harm et al Exter Polak & Charlouis B.V.,P.O. Box 3241 2280 GE Rijswijk 2280 GE Rijswijk (NL)