CPC Subgroup
E21B 17/05 Swivel joints
Full Title
Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Casings; Tubings > Couplings; joints > between rod and bit or between rod and rod > Swivel joints
E21B 17/05 Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Casings; Tubings > Couplings; joints > between rod and bit or between rod and rod > Swivel joints