Patent ID: 7625188
Filing Date: 2009-12-01
Classification: A61M,F01L,Y10T

Abstract:
1. A pump, comprising: a housing having a pump chamber with an inlet and an outlet for connection to suction and discharge conduits; a pump element in the pump chamber that strokes between a retracted and an extended position to pump fluid from the chamber; a motor mounted to the housing, the motor rotating a drive shaft; a reversing mechanism coupled between the drive shaft of the motor and the pump element for converting rotary motion of the drive shaft to reciprocal stroking movement of the pump element while the drive shaft continues to rotate in the same direction; the reversing mechanism having a mechanical stroke length controller for varying a stroke length of the pump element in response to changes in fluid pressure in the pump chamber; a cam that rotates relative to the housing an increment of one turn in a first direction while the reversing mechanism is in an extension mode and an increment of one turn in a second direction while the reversing mechanism is in a retraction mode; and a cam follower in engagement with the cam and being axially movable in unison with the pump element along an axis of the pump element, the cam pushing the cam follower and the pump element toward the extended position while the reversing mechanism is in the extension mode.