PERCUSSION DRILL WITH DEVICE FOR SPONTANEOUS IMPACT PREVENTION Russian patent published in 2005 - IPC

FIELD: drilling tools with electric drives, particularly for drilling with combined rotary and percussive action.

SUBSTANCE: percussion drill comprises boring bit, case, piston member arranged behind boring bit to perform reciprocal movement, rotary drive, intermediate shaft, which performs rotational movement when drive imparts rotation to the shaft and rotary mechanism to transmit rotation from drive to boding bit. Device also has transforming mechanism, which transforms intermediate shaft rotation into reciprocal movement of the piston member. Percussion mechanism includes pane brought into engagement with piston member to transmit strokes from percussion drill to boring bit. Percussion drill has shifting member for selective preventing of rotation transmission from drive to transforming mechanism. Shifting member is actuated from outer case side to select one of at least two operation modes, namely rotor drilling mode in which only rotation is transmitted from drive to boring bit and rotary-percussion drilling mode in which rotation from drive is transmitted along with percussion drill strokes. Blocking mechanism is connected with switching member so that blocking mechanism may restrict piston from reciprocal movement only in rotary drilling mode.

EFFECT: provision of drilling in rotary and rotary-percussive regimes, prevention of spontaneous impacts.

19 cl, 29 dwg