(19)

(11)

EP 4 511 558 A1

(12)

(43) Date of publication: 26.02.2025 Bulletin 2025/09 (21) Application number: 23755514.9 (22) Date of filing: 18.07.2023

(51) International Patent Classification (IPC):  E21B 7/02(2006.01) E21B 19/08(2006.01) E21B 19/20(2006.01) E21B 19/14(2006.01) E21D 20/00(2006.01) E21B 19/15(2006.01) (52) Cooperative Patent Classification (CPC): E21B 7/025; E21B 19/146; E21B 19/08; E21D 20/006; E21B 19/20; E21B 19/155 (86) International application number: PCT/US2023/028045 (87) International publication number: WO 2024/020043 (25.01.2024 Gazette 2024/04)

(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 ME MK MT NL NO PL PT RO RS SE SI SK SM TR Designated Extension States: BA Designated Validation States: KH MA MD TN (30) Priority: 19.07.2022 US 202263390386 P 18.08.2022 US 202263398912 P (71) Applicant: J.H Fletcher & Co. Huntington, WV 25722-2187 (US)	(72) Inventor: BURGESS, Robert D. Huntington, West Virginia 25705 (US) (74) Representative: AOMB Polska Sp. z.o.o.  ul. Rondo Ignacego Daszynskiego 1 00-843 Warsaw 00-843 Warsaw (PL)