(19)

(11)

EP 4 051 872 A1

(12)

(43) Date of publication: 07.09.2022 Bulletin 2022/36 (21) Application number: 20821437.9 (22) Date of filing: 24.09.2020

(51) International Patent Classification (IPC):  E21D 20/00(2006.01) (52) Cooperative Patent Classification (CPC): E21D 20/003 (86) International application number: PCT/SE2020/050901 (87) International publication number: WO 2021/061043 (01.04.2021 Gazette 2021/13)

(84) Designated Contracting States: AL 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 RS SE SI SK SM TR Designated Extension States: BA ME Designated Validation States: KH MA MD TN (30) Priority: 24.09.2019 SE 1951078 (71) Applicant: Drillpipe AB 141 32 Huddinge (SE)	(72) Inventor: STÅLNACKE, Gunnar 195 93 Märsta (SE) (74) Representative: Zacco Sweden AB  P.O. Box 5581 Löjtnantsgatan 21 114 85 Stockholm 114 85 Stockholm (SE)