This invention relates to portable powered abrading tools, such as power sanders, of a type having an abrading shoe mounted for straight line reciprocating movement relative to a carrying body.
U.S. Pat. Nos. 3,932,963 and 4,052,824, and pending U.S. patent application Ser. No. 869,373 filed Jan. 13, 1978 by Mr. Alma A. Hutchins on "Straight Line Abrading Tool With Balancing Counterweight", are directed to a type of straight line reciprocating abrading tool in which a handle body containing a motor carries at its underside a shoe plate which is guided for reciprocating movement relative to the body and is driven for such movement by the motor. A sanding pad or other abrading unit can be secured to the reciprocating shoe for movement therewith. The motor is desirably a piston and cylinder mechanism acting to rotatably oscillate spaced gears carried at the underside of the handle body, with the gears engaging racks projecting upwardly from the shoe plate to reciprocate the shoe in response to rotary oscillation of the gears. Application Ser. No. 869,373 shows a counterweight unit in such an arrangement, located between the underside of the handle body and the upper surface of the reciprocating shoe. The shoe is retained and guided by tracks or other guide means projecting downwardly from the body and engaging the underside of the shoe plate to retain it against downward movement away from the body. The shoe plate is retained at its upper side by engagement with bearing elements carried at the bottom of the handle body.