US 12,241,313 B2
Connection for percussion drilling
John Hammargren, Ockelbo (SE); and Andreas Norman, Sandviken (SE)
Assigned to Sandvik Mining and Construction Tools AB, Sandviken (SE)
Appl. No. 16/978,823
Filed by SANDVIK MINING AND CONSTRUCTION TOOLS AB, Sandviken (SE)
PCT Filed Feb. 22, 2019, PCT No. PCT/EP2019/054455
§ 371(c)(1), (2) Date Sep. 8, 2020,
PCT Pub. No. WO2019/170437, PCT Pub. Date Sep. 12, 2019.
Claims priority of application No. 18160853 (EP), filed on Mar. 9, 2018.
Prior Publication US 2020/0408048 A1, Dec. 31, 2020
Int. Cl. E21B 17/042 (2006.01); E21B 1/00 (2006.01); F16L 15/06 (2006.01)
CPC E21B 17/0426 (2013.01) [F16L 15/06 (2013.01); E21B 1/00 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A connection for percussion drilling comprising:
a male coupling including a body and a male screw thread formed on an outer surface of the body; and
a female coupling including a body and a female screw thread formed in an inner surface of the body, wherein each of the male and female screw threads has a thread-form including a crest, a root, a contact flank and a non-contact flank, each thread-form having a contact flank angle and a non-contact flank angle inclined relative to a respective baseline located at a respective minor diameter or major diameter thereof, each non-contact flank angle being greater than the respective contact flank angle, wherein the crest of each thread-form is inclined from the respective contact flank to the respective non-contact flank such that an apex of the respective thread-form defining the respective minor diameter and major diameter thereof is located adjacent to the respective non-contact flank, wherein each root has a first arc, and each contact flank is connected to the respective root by a respective second arc, and wherein a first radius of each first arc is greater than a second radius of the respective second arc only on the contact flank, wherein the non-contact flank has an additional single arc having just one radius, the additional single arc being tangent with the non-contact flank.