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

FIELD: mining.

SUBSTANCE: drill bit comprises hollow body with connection thread and vanes reinforced with rock-crushing elements and flushing system including pressure and dual flushing channels. Some of said channels, the offtake channels, are equipped with nozzle and communicated with the body chamber while other channels are connected with central chamber on the body outer surface. Said offtake channels are equipped with sleeves of rectangular flow section. Note here that every said sleeve is furnished with bimetal plate. Said plate is rigidly connected with sleeve case to shut off flushing channel flow section at the body temperature increase.

EFFECT: higher efficiency of drill bit operation owing to improved flushing.

2 cl, 2 dwg