(19)

(11)

EP 2 350 431 A1

(12)

(43) Date of publication: 03.08.2011 Bulletin 2011/31 (21) Application number: 09758568.1 (22) Date of filing: 29.05.2009

(51) International Patent Classification (IPC):  E21B 19/16(2006.01) B25B 13/50(2006.01) (86) International application number: PCT/NO2009/000199 (87) International publication number: WO 2009/148321 (10.12.2009 Gazette 2009/50)

(84) Designated Contracting States: AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR (30) Priority: 05.06.2008 NO 20082637 (71) Applicant: Norwegian Hard Rock Drilling AS 4441 Tonstad (NO)	(72) Inventors: HAUGHOM, Per, Olav N-4440 Tonstad (NO) HAUGHOM, Sigurd, Kjell N-4440 Tonstad (NO) (74) Representative: Håmsø Patentbyrå ANS  Postboks 171 4302 Sandnes 4302 Sandnes (NO)