Patent ID: 6484823
Filing Date: 2002-11-26
Classification: E21B,F16K

Abstract:
A rock-crushing rotary drill bit comprising:a bit body forming at least one leg; and a rotatable roller rotatably mounted on the at least one leg by bearings, the roller including rock crushing elements; the bit body further including: an external thread adapted for connecting the bit body to a drill tube, a main channel for conducting flushing medium, a first flushing channel passing through the at least one leg and communicating with the main channel for conducting flushing fluid therefrom to flush the bearings, a second flushing channel communicating with the main channel and including a discharge recess for discharging flushing medium from the bit body, the discharge recess defining a linear center axis, a nozzle disposed at a downstream end of the discharge recess for directing flushing medium in a direction to flush-away cuttings, and a valve element disposed at an upstream end of the discharge recess and including a guide structure for guiding the valve element in linear movement along the center axis, the valve element being spring-biased to a closed state for closing the discharge passage, and being yieldable in response to fluid medium pressure acting thereagainst, for opening the discharge recess.