Abstract: A diaphragm pump for pumping a fluid, such as paint, includes a diaphragm separating a first chamber for accommodating and dispensing the paint from a second chamber for accommodating a drive fluid, and a piston that reciprocates to drive the drive fluid within the second chamber in order to flex the diaphragm to provide the pumping action within the first chamber. The diaphragm pump also includes a backing ring mounted adjacent the diaphragm that is configured to distribute the drive fluid across the diaphragm to cause a flexible region of the diaphragm to flex toward the first chamber from the outer perimeter inward toward a central pumping surface in a rolling manner. This diaphragm movement results in substantially all of the paint adjacent the diaphragm within the first chamber to move out of the first chamber when the diaphragm reaches its travel limit, and thus improves the efficiency of the diaphragm pump.

Abstract: A detent apparatus and method for rotatably retaining a paint spray tip and turret in a holder to permit rotation of the turret to selectively position the tip to a spraying position and a cleaning position and to selectively permit extraction and insertion of the turret with respect to the holder by actuation of the detent apparatus which is preferably made up of a protrusion and mating recess and shoulder, with a spring portion permitting relative movement of the elements of the detent apparatus to permit withdrawal and insertion of the turret with respect to the holder.

Abstract: A pressure relief assembly for use with a paint pump having a chamber with a pressure relief port located immediately adjacent an inlet port of the pump. The pressure relief assembly includes a mounting member, inlet washer, rupture pad and outlet washer. The mounting member is threaded on its exterior surface and includes an inlet end, an outlet end, and a relief passage extending between the inlet and outlet ends. A rupture recess in the inlet end is sized to receive the inlet washer, rupture pad and outlet washer, with the rupture pad positioned between the washers. The inner diameter surface of the outlet washer is convex. The pressure relief assembly is screwed into the pump with the inlet end adjacent to the pressure relief port. The rupture pad forms a seal between the pump chamber and atmosphere that ruptures to vent the chamber when the pressure within the chamber exceeds a predetermined rupture pressure.

Abstract: A user-replaceable pumping chamber for a consumer piston pump has a reciprocating piston seal secured to the end of a piston by a threaded fastener. The chamber further has a smooth-bored cylindrical sleeve surrounding the seal to form a cylindrical wall for the chamber. The seal is retained to the piston by a threaded shoulder screw and washer acting against an O-ring in an end face of the seal. The housing has an aperture providing access to the cylindrical sleeve to permit levering a worn sleeve out of the housing.

Abstract: A reciprocating cutter incorporating at least one saw blade and being optionally provided with a cooperating guard. The guard provides a protective cover for the blade or blades of the cutter and, through a spring-loaded biasing thereof, cooperates with the cutter to both stabilize the blade or blades and the workpiece and provide a degree of control for the movement of the cutter through the workpiece. The cutter, which may utilize a single reciprocating blade with which a spring-biased guard cooperates, in most instances will comprise a pair of alternately reciprocating blades, the teeth of which are selectively set to define a single clean kerf in the workpiece. The blade or blades can comprise the sole cutting device in a hand-held motor-driven implement, or alternatively can constitute an attachment, either permanent or removable, for a hand-held motor-driven hedge trimmer incorporating reciprocating trimmer blades to which the saw blades will be operably joined for simultaneous reciprocation therewith.