PERCUSSIVE-ROTARY MECHANISM OF HAND-CARRIED ELECTRIC TOOL Russian patent published in 2000 - IPC

FIELD: portable power tools. SUBSTANCE: primarily relates to portable electric power tools intended for percussive drilling in stone and concrete. Percussive-rotary mechanism has body, axially movable power-driven spindle, anvil and striker which are spring-biased relative to each other. Striker is provided with end-face cams. Anvil is rigidly pressed into body of mechanism coaxially to spindle. Striker is installed on spindle and secured by means of pin which is fastened in aligned through-holes of striker and spindle. Striker is provided with cone-shaped tail-piece which is treated by high-frequency current to hardness of 46-52 HRC. Cams of anvil and striker have total angle consisting of 70-74 deg angle created by curvilinear oncoming surface and plane of circumference radius and 43-50 deg angle created by plane of circumference radius and downcoming surface of cam. Aforesaid embodiment of percussive- rotary mechanism allows for increasing energy of blow together with reduction of contact stresses on surface of cams. In addition, units of mechanism structure are simplified. EFFECT: higher efficiency. 8 dwg