Rotary and impact operated pneumatic drill - has electromechanical or mechanical coupling to disconnect crank drive for reciprocating mechanism

摘要

The pneumatic hammer with a rotary and reciprocating mechanism as in the main patent, has a gearwheel system for the rotary drive, connected to an eccentric crank mechanism which drives a piston in line with the tool bit. This acts against an impact member for the reciprocating drive. In the region of the crank is a coupling to disconnect the crank drive. This has a sliding block which can be moved along the drive shaft by means of an operating arm extending through the casing. This has driving teeth which are disengaged from corresponding teeth on the plate carrying the eccentric crank drive member. A magnetic coupling can alternatively be used, operated by a changeover switch.