Patent 6877235 was granted and assigned to Hitachi on April, 2005 by the United States Patent and Trademark Office.
A counterweight is provided to cancel axial vibration of a plunger of a saber saw. Swing rollers, rotatably supported at both ends of a roller shaft provided at a rear end of the plunger, are interposed between a pair of opposing tracks formed in an axially elongated groove formed on the counterweight.