Patent ID: 7811072
Filing Date: 2010-10-12
Classification: F01C,F04C

Abstract:
1. A gear pump for use with a hand-operated tool having a rotatable shaft, said gear pump comprising: a housing having a chamber, an inlet for fluid into the chamber and an outlet for fluid from the chamber, wherein the housing comprises a top wall, a bottom wall, and at least one side wall extending around the chamber between the top and bottom walls; and a gear assembly comprising at least one gear mounted for rotation within the chamber between the inlet and outlet, and a drive shaft extending from the gear and externally of the chamber, wherein the drive shaft extends from a central axis of the gear, from each face of the gear, and the gear rotates about this axis, wherein: the housing comprises a bottom bearing extending downwardly from the bottom wall of the housing and a top bearing extending upwardly from the top wall of the housing, such that opposing ends of the drive shaft locate and rotate within said bearings; the top bearing is open-ended and the drive shaft extends sealingly there through; there is a clearance between the top bearing and the tool-engaging end of the drive shaft, so as to accommodate any eccentricity in the rotation of the rotatable shaft of the tool; the top bearing comprises a stepped diameter that provides a shoulder, an annular seal of the housing extends around the drive shaft and is sandwiched between an upper face of the at least one gear and the shoulder of the top bearing; and a tool-engaging end of the drive shaft is engageable with the rotatable shaft of the hand tool such that rotation of the drive shaft by the hand tool causes fluid to move between said inlet and outlet.