Abstract: A pumping system for producing uniform discharge and suction rates includes a pump connected to a supply of hydraulic fluid to deliver hydraulic control fluid at a selectable flow rate to a proportioning valve. The proportioning valve divides the flow of hydraulic fluid into two resulting flows, each of which is utilized via a four-way valve to drive a piston within a hydraulic cylinder. The positions of the pistons within the cylinders are detected and used to control the proportioning valve such that each piston is imparted with a velocity that varies in a sinusoidal manner in response to the hydraulic fluid delivered to it by the porportioning valve. Sensing of the piston positions and control of the proportioning valve may be accomplished mechanically by a system of cams driven by the pistons, or electronically by a microprocessor receiving signals from transducers coupled to the pistons.

Abstract: A rotary cutting tool for forming fluted rotors and the like comprising a cylindrical body having a plurality of metallic carbide cutting blades which are detachably mounted on the circumference of the body. The blades are arranged along a helical line with respect to the axis of rotation of the cutter body. The blades may be circumferentially spaced apart equidistant, one blade from each adjacent blade, to form only one turn of the helix and whereby each blade may be easily ground to a precise cutting edge contour while mounted on the cutter body. The cutting edge contour of each blade may be such that each blade cuts portions along the entire profile of the form produced on the workpiece.

Abstract: A rotary cutting tool for forming fluted rotors and the like comprising a cylindrical body having a plurality of metallic carbide cutting blades which are detachably mounted on the circumference of the body. The blades are arranged along a helical line with respect to the axis of rotation of the cutter body. The blades may be circumferentially spaced apart equidistant, one blade from each adjacent blade, to form only one turn of the helix and whereby each blade may be easily ground to a precise cutting edge contour while mounted on the cutter body. The cutting edge contour of each blade may be such that each blade cuts portions along the entire profile of the form produced on the workpiece.