Abstract: A motor driven by air or other fluid, or a pump for pumping air or another fluid, including a rotor having a porous metal body formed of compacted and sintered metal particles and containing polytetrafluoroethylene embedded within the pores of the body. The metal particles are preferably primarily of iron, with a smaller amount of copper at least partially dissolved in the iron. The metal body carries vanes which are received slidably within slots in the body and are movable radially relative thereto and are preferably formed of resinous plastic material.

Abstract: A vacuum cleaner having a rotor which is mounted to turn at the inside of a filter bag of the device, and which acts when turned to contact the bag and displace accumulated dust from its outer surface. The rotor may be actuable from the outside of the cleaner when a cover of the cleaner is in closed active condition. The rotor desirably includes one or more resiliently flexible arms which are deflectable to a reduced diameter condition by the bag when the bag is constricted inwardly against and about the rotor by the flow of suction air when the device is in use.

Abstract: A portable abrading tool with a rotary backing unit for carrying a disc of abrading material, with abraded particles being drawn through a passage or passages in the backing unit into a shroud carried at a rear side of that unit, and with the backing unit carrying a circular rib at its rear side projecting rearwardly within a peripheral edge portion of the shroud in axially overlapping relation to define a shoulder blocking centrifugally induced radially outward movement of abraded particles toward the edge portion of the shroud.

Abstract: A portable abrading tool having a shoe mounted for straight line reciprocating movement relative to a body, and driven by a reciprocating piston in the body through two spaced gear units, with a counterweight being driven by those gear units to reciprocate essentially with the piston and oppositely from the shoe, and with the counterweight desirably having two enlarged end portions and an intermediate reduced width portion carrying oppositely facing toothed racks engaging the two gear units respectively. The counterweight is desirably confined vertically between the body of the tool and the reciprocating shoe, and is slidably located within recesses in the under surface of the body.