Patent ID: 7686601

Claim:
A telescoping gear pump, comprising: a hollow seal housing having a cavity formed therein, at least one inlet port for fluid into said cavity and at least one outlet port fluid out of said cavity; a first gear disposed in said cavity and having a plurality of teeth; a second gear disposed in cavity and having a plurality of teeth meshing with said teeth of said first gear; a shaft rotatably mounted to said housing, said second gear being attached to said shaft for co-rotation and said first gear being axially moveable along said shaft relative to said second gear for varying a displacement of said cavity; a tubular rotary first seal rotatably disposed in said cavity and having a plurality of teeth engaging said teeth of said first gear; and a tubular rotary second seal disposed in said cavity and having a plurality of teeth engaging said teeth of said second gear whereby when pressured liquid is supplied to said at least one inlet port, the pressured fluid rotates said first and second gears causing said shaft to rotate for operation as a motor, and when said shaft is rotated, said second gear rotates said first gear for operation as a pump causing fluid to flow from said at least one inlet port to said at least one outlet port and wherein said first gear and said second seal are free to move along an axis of said shaft in said cavity in response to internal pressure in said housing, wherein the tubular rotary first seal and the tubular rotary second seal have cooperating steps to accommodate a predetermined radial distortion without fluid leakage, the cooperating step of the tubular rotary first seal engaging the first gear and the cooperating step of the tubular rotary second seal engaging the second gear, the telescoping gear pump thereby maintaining a seal of the first and second gear in a pressure loaded condition.