ROLLER BIT Russian patent published in 1999 - IPC

FIELD: drilling equipment. SUBSTANCE: roller bit has holder with lugs which are provided with protruding cantilever journals, and rolling cutter which is made in the form of hollow body with teeth protruding above its surface. Rolling cutter is adapted for rotation on journals. Teeth and body of rolling cutter have through-passages. Installed in these through-passages with possibility of reciprocating motion are pistons or strikers which rest against journal. Journal itself is provided with cams which can withdraw strikers inwards in passages when teeth are embedded in work face. Application of aforesaid embodiment of roller bit enhances operating performance due to increased speed of drilling and larger length of drilled bore-hole per single roller bit. EFFECT: higher efficiency. 2 dwg