Patent ID: 6832900
Filing Date: 2004-12-21
Classification: F04B,Y10T

Abstract:
A piston and drive shaft assembly for a pump, comprising:a first piston assembly eccentrically mounted to the drive shaft and including a first piston having a head and connecting rod and including a first mass member coupled to the first piston; and a second piston assembly eccentrically mounted to the drive shaft in opposition to the first piston assembly and including a second piston having a head and a connecting rod and including a second mass member coupled to the second piston; wherein a mass of the first piston is less than a mass of the second piston and wherein a mass of the first mass member is greater than a mass of the second mass member such that the first piston assembly has essentially the same mass as the second piston assembly and the moments acting on the drive shaft from the first and second piston assemblies are essentially in equilibrium.