SUBMERSIBLE IMPACT BIT ASSEMBLY Russian patent published in 2018 - IPC E21B4/14 E21B10/36 E21B1/00 

FIELD: drilling of soil or rock.

SUBSTANCE: group of inventions relates to the field of impact drilling by submersible hammers. Submersible impact bit assembly includes a drill bit having a front cutting end and a rear support end, an inner channel extending along the longitudinal axis of the assembly from the support end to the cutting end, bottom check valve installed partially in the channel and extending axially from the support end, the reciprocal support regions respectively formed on the radially inwardly facing surface of the channel and on the radially outwardly facing surface of the bottom check valve, the respective support areas being shaped to support one another and to axially lock the bottom check valve on the drill bit. Support areas include a plurality of radially projecting tabs spaced in a circumferential direction about an axis, and a plurality of radially extending protrusions spaced in a circumferential direction about the axis. Separation distance along the periphery between the projections is at least equal to or greater than the length along the periphery of the tabs, to ensure the passage of the tabs along the axis between the projections without significant radial deformation of the bottom check valve. Rear axial end of each foot is beveled radially to provide a support contact surface, and the front axially end of each protrusion is beveled radially to obtain a support contact surface. Radial length of the tabs and protuberances is such that when the legs are positioned axially behind the protrusions, the contact surfaces of the tabs and protrusions are mated together with the radial overlap in the channel and provide frictional landing areas that are axially locked and prevent independent rotation of the bottom check valve in the drill bit.

EFFECT: provided resistance to mechanical and thermal stresses when used, minimized propensity to shear, fracture or separation of the bottom check valve from the drill liner shank during use, increased service life of the check valve.

14 cl, 10 dwg