Patent ID: 7246533

Claim:
A mechanism for converting rotary motion into reciprocating motion comprising: a housing; a counterweight; a reciprocating shaft assembly adapted for reciprocal movement along a longitudinal axis; a drive assembly operatively connected to the shaft assembly for driving the shaft assembly in a reciprocal motion, and the drive assembly operatively connected to the counterweight for driving the counterweight in a reciprocal motion; and a crank gear comprising; a first crank gear surface; a second crank gear surface substantially parallel to the first crank gear surface; a first crank shaft extending eccentrically from the first crank gear surface, the first crank shaft operatively connected to the reciprocating shaft assembly; and a second crank shaft extending eccentrically from the second crank gear surface, the second crank shaft operatively connected to the counterweight; wherein the counterweight comprises a slide which rides in a slot formed on an inside surface of the housing; the counterweight slide comprising: a first tab extending from the periphery of the counterweight, and a second tab extending from the periphery of the counterweight in a direction opposite the first tab with respect to an axis of reciprocating motion, wherein a thickness of at least a portion of the counterweight is greater than a width of the slot in a direction perpendicular to the reciprocal motion of the counterweight.