DRILLING BIT Russian patent published in 2014 - IPC E21B10/60 

FIELD: mining.

SUBSTANCE: drilling bit comprises a body with working elements and washing units placed between them, comprising a hollow nozzle with a stop collar for fixation of the nozzle relative to the body. Each nozzle is made in the form of several telescopically arranged bushings, the lower of which is installed as capable of axial displacement, and is equipped with a tension spring, one end of which is connected to the body, and the other one - with the movable bushing, the lower part of which is equipped with brushes, arranged at the side of bit rotation, at the same time the channel of the nozzle is made with an alternating cross section, besides, the minimum cross section is in the lower bushing.

EFFECT: improved cleaning of a bottomface from sludge, increased efficiency of bit operation.

3 cl, 2 dwg