Patent ID: 8307910

Claim:
A drive apparatus for a reciprocating tool, comprising; a housing; a rotatable drive shaft assembly located in said housing; an elongated spindle located in said housing for reciprocating motion, said spindle having a front end portion for attaching a cutting blade thereto and a rear portion; a front bushing in said housing for supporting the front end portion of said spindle, said bushing permitting reciprocating and limited angular motion of said spindle therein; and a wobble drive mechanism comprising a wobble drive shaft connected to said drive shaft assembly, an elongated arm having a lengthwise axis extending upwardly from said wobble drive shaft and including an upper interface for reciprocating said spindle generally in its lengthwise direction during alternating cutting and return strokes; wherein said upper interface connects said arm to said spindle in a manner that prevents translational movement of said spindle relative to said arm in the direction of the arm lengthwise axis and therefore causes a cutting blade attached to said front end portion to travel through an arc-like path that is traversed in said cutting and return strokes: wherein said upper interface is configured for limited rotational movement, with respect to said arm, about the lengthwise axis of the arm but is prevented from axial movement along the lengthwise axis, with respect to said arm.