JAR WITH CURRENT LEAD FOR ELECTRIC DRILL Russian patent published in 2019 - IPC E21B31/113 

FIELD: soil or rock drilling.

SUBSTANCE: invention relates to drilling of wells with electric drills and serves for elimination of clamping of borehole drilling tool. Proposed device comprises hollow shaft fitted in oil-filled case with end seals. Internal hole in the shaft is intended for circulation of drilling fluid. Housing is divided into three working chambers: splined chamber with current feed mechanism, hammer and anvil chamber with hydraulic cylinder and chamber with friction trigger (latch). Spline part transmits torque from drill string to rock cutting tool and provides unobstructed axial movement of shaft relative to housing. Current feed mechanism is required for high-voltage transmission to electric motor through jar moving parts made in the form of fixed slats and movable wedge-shaped knife arranged in splined part of jar. In order to insulate electric contacts, inner cavity of chamber is filled with dielectric transformer oil. Impact section is intended for application of powerful impacts of striker on surface of anvil. Hydraulic cylinder serves to create time delay when pulling the drill string. Latch is a mechanical retainer blocking the shaft from axial displacements in the housing until the force of tension or compression of the drill string exceeds its unlocking value.

EFFECT: reliable mechanism of current feed to electric motor during operation of jar up or down.

7 cl, 4 dwg