QUICK-DETACHABLE THREADED CONNECTION WITH MULTI-THREAD THREAD Russian patent published in 2019 - IPC E21B17/00 E21B17/02 E21B17/42 F16L15/00 

FIELD: soil or rock drilling.

SUBSTANCE: invention relates to drilling operations, namely to threaded connection or lock for connection of tools used in horizontal directed drilling to drill string. Threaded connection for connection of detachable downhole tool assembly to drill string comprises lower end part made for connection to detachable downhole tool assembly, upper end part opposite to lower end part and made for connection with drill string in membrane lock. Upper end part includes: coupling end element with a non-threaded first peripheral surface having a first middle inner diameter and a non-threaded second peripheral surface having a second middle inner diameter greater than said first diameter, threaded cone-shaped section between first and second non-thread peripheral surfaces, wherein threaded cone-shaped section includes thread on it. Lower end part includes a nipple end element with a non-threaded first peripheral surface having a first middle outer diameter, and a non-threaded second peripheral surface having a second middle outer diameter greater than said first diameter, threaded cone-shaped section between first and second non-thread peripheral surfaces, wherein threaded cone-shaped section includes thread on it. Note here that, at least, selected surfaces of non-threaded first and second peripheral surfaces on nipple and coupling end elements are slightly tapered. Thread on threaded cone-shaped sections of nipple and coupling end elements forms a multi-thread thread. At that, nipple end element contains sub, which includes the first connecting structure provided on the first end of the sub, wherein the adapter has a second end forming a second nipple connection structure comprising a conically shaped threaded section with large and small outer diameters, wherein the adapter comprises an intermediate zone between the first connecting structure and the second, nipple, connection structure, and in the intermediate zone there are multiple drive faces. Coupling connecting element has multiple drive faces, which are made with possibility of alignment with drive faces provided in intermediate zone between first and second connection structures of sub. Multi-thread thread shape on the nipple end element provided on the second end of the sub is made for screwing with the mating form of the multi-thread thread provided in the coupling end element, wherein the multi-thread thread shape are adjusted such that when the joint is screwed together and the drive faces on the sub contact with the drive faces in the coupling end element, said faces do not match, so that a drive mismatch is obtained.

EFFECT: high strength and durability of the threaded connection.

6 cl, 11 dwg