Patent attributes
A power tool includes a housing, a rotary motor disposed in the housing, a jack shaft coupled to the motor and a spindle mounted in the housing for carrying a tool. A first wobble plate assembly is coupled to the jack shaft for driving the spindle to reciprocate at least approximately linearly in a linear path along a predetermined axis. A counterweight is mounted in the housing for performing a rotative reciprocating motion and pivoting relative to the housing about a pivot axis. The pivot axis is disposed in a plane perpendicular to the predetermined axis and fixed relative to the housing. A second wobble plate assembly is coupled to the jack shaft for driving the counterweight. The use of the counterweight results in no friction or restriction with a large stroke and large area, so that stability is improved, fitting of the counterweight is simple and cost is reduced.
