Pumps with floating wrist pins

Abstract

Multi-cylinder in-line and radial pumps having an improved structure for coupling the piston heads to the crankshaft such that the number of parts commonly employed and the size of the resulting pump is greatly reduced when compared to prior art pumps now on the market. Both in-line piston pumps and radial diaphragm pumps are included. The connecting rods comprise plates, each having a bore through the thickness dimension thereof for receiving a cylindrical lobe formed eccentrically on the pump's crankshaft. Formed on one end of each of the connecting rods is a generally cylindrical bore, also extending through the thickness dimension of the connecting rod, the center of this bore being displaced inwardly of the end edge surface of the connecting rod by a distance which is less than the radius of the bore. A cylindrical wrist pin having a flat formed on a peripheral surface thereof is insertable into the bore or recess at the end of the connecting rod and when the pin is rotated so that its flat portion is aligned parallel to the end edge of the connecting rod, it is firmly locked in place but rotatable or floating within the recess. A bore formed perpendicular to the flat on the floating wrist pin is threaded to receive a bolt used to fasten the plunger rod to the floating wrist pin. Other features of the pumps of the present invention include a cylinder head designed to receive sleeve inserts of differing sizes whereby pistons of differing cross-sectional areas can be utilized to vary the capacity of the pump, and grooved shoulders on the connecting rods to cooperate with holding rings around the crankshaft.