Patent ID: 7637018

Claim:
A power tool, comprising: a housing; a rotary motor disposed in said housing; a jackshaft coupled to said rotary motor; a spindle mounted in said housing for carrying a working member; a first wobble plate assembly mounted on or coupled to said jackshaft for driving said spindle to reciprocate at least approximately linearly in a linear path along a predetermined axis; a counterweight mounted in said housing for performing a reciprocating motion relative to said housing, said counterweight being pivotable relative to said housing about a pivot axis, to perform said reciprocating motion as a rotative reciprocating motion, said pivot axis disposed in a plane perpendicular to said predetermined axis and fixed relative to said housing; and a second wobble plate assembly mounted on or coupled to said jackshaft for driving said counterweight, said second wobble plate assembly having a second wobble arm, and said counterweight being pivotally mounted on a first transverse pin and on a second transverse pin, permitting said second wobble arm to drive said counterweight to pivotally rotate relative to said housing about said pivot axis.