DRILL WITH BREAK-OUT CUTTING HEAD Russian patent published in 2009 - IPC B23B51/02 

FIELD: mechanical engineering and metal working.

SUBSTANCE: proposed drill comprises cutting head arranged on stem front end and comprising cutting and clamping surfaces. Cutting surface has end face and base surfaces and side surface arranged there between. Base surface is arranged across rotational axis. Clamping surface seat opposite end face surface, runs backward from base surface and has locking surface arranged on periphery relative to rotational axis. Cutting head has at least two grooves running along periphery of cutting and clamping surfaces to make identical segments between pair of grooves. Every segment comprises mortise open towards side and base surfaces and dividing base surface into first and second base surfaces. It comprises also wall to transmit torque, passing along mortise section and across base surface, and locking mortise that divides head clamping surface into 1^st and 2^nd locking surfaces. Note here that two grooves pass along stem periphery to make identical jointing parts there between. Every jointing part, on stem front, comprises bearing surface and clamping surface. Stem locking mortise divides stem locking surface into 1^st and 2^nd locking surfaces. Ledges extend from every bearing surface to divide it into 1^st and 2^nd bearing surfaces. Stem wall to transmit torque passes along ledge section and across base surface to face direction of rotation. Note here that pairs of head segments and those of stem jointing parts conjugate, and, for each such pair, 1^st base surface interacts with 1^st stem bearing surface, while head 2^nd base surface interacts with stem 2^nd bearing surface. Head wall to transmit torque interacts with stem wall (82) to transmit torque. Head 1^st locking surface interacts with stem 1^st locking surface, while head 2^nd locking surface interacts with stem 2^nd locking surface.

EFFECT: higher efficiency.

14 cl, 9 dwg