Oiler pump

Abstract

An oiler pump comprises a housing defining a cylinder and a chamber, a manually displaceable piston received in the cylinder, a spring in the chamber between the housing and the piston, a first one-way check valve on a first end of the piston, a second one-way check valve on the housing, and a fluid displacement member substantially completely filling the chamber when the piston is in a retracted position and to substantially completely open the chamber when the piston is in the first position. The fluid displacement member is formed by an outer skirt member and an inner guide member formed integrally with the piston member. The fluid displacement member increases the priming height and efficiency of the pump by reducing the volume area in the chamber in the fully compressed state which might accumulate gas to zero.

1 . A fluid pump comprising:
 a housing defining a cylinder and a chamber in fluid communication with the cylinder;   a manually displaceable piston received in the cylinder, the piston having a distal end, a proximal end, and a fluid payout conduit extending between the distal end and the proximal end, the piston being slidable within the cylinder between first and second positions relative to the housing;   a spring received in the chamber between the housing and the proximal end of the piston, the spring biasing said piston toward said first position;   a first one-way check valve on the distal end of the piston in fluid communication with said fluid payout conduit;   a second one-way check valve on the housing and in fluid communication with said chamber; and,   a fluid displacement member adapted to substantially completely fill said chamber when the piston is in said second position and to substantially completely open (empty/vacate) said chamber when the piston is in said first position.   
   
   
       2 . The fluid pump according to  claim 1  wherein said fluid displacement member includes an annular member surrounding said spring. 
   
   
       3 . The fluid pump according to  claim 2  wherein said annular member is movable with said piston. 
   
   
       4 . The fluid pump according to  claim 3  wherein said annular member is formed integrally with said piston. 
   
   
       5 . The fluid pump according to  claim 1  wherein:
 said spring is a coil spring defining an inner cylindrical hollow area; and,   said fluid displacement member includes a cylindrical member disposed within said inner cylindrical hollow area.   
   
   
       6 . The fluid pump according to  claim 5  wherein said cylindrical member is movable with said piston. 
   
   
       7 . The fluid pump according to  claim 6  wherein said cylindrical member is formed integrally with said piston. 
   
   
       8 . The fluid pump according to  claim 1  wherein:
 said spring is a coil spring defining an inner cylindrical hollow area; and,   said fluid displacement member includes an annular member surrounding said spring and a cylindrical member disposed within said inner cylindrical hollow area.   
   
   
       9 . The fluid pump according to  claim 8  wherein:
 said annular member and said cylindrical member forming said fluid displacement member are movable with said piston.   
   
   
       10 . The fluid pump according to  claim 9  wherein said annular member and said cylindrical member forming said displacement member are formed integrally with said piston. 
   
   
       11 . The fluid pump according to  claim 1  wherein:
 said piston is formed of a plastic materials and carries an o-ring gasket sealing member adapted to engage an inner surface of said cylinder.   
   
   
       12 . The fluid pump according to  claim 1  wherein:
 said first one-way check valve includes a compliant check valve ball having a durometer within a range of about 60 D to 70 D; and,   said second one-way check valve includes a compliant check valve ball having a durometer within a range of about 60 D to 70 D.   
   
   
       13 . The fluid pump according to  claim 12  wherein said first and second compliant check valve balls are formed of the same rubber material having said durometer within a range of about 60 D to 70 D. 
   
   
       14 . The pump according to  claim 1  wherein said second one-way check valve includes:
 a compliant check valve ball; and,   a fitting having a passageway extending therethrough defining a longitudinal axis and having a ball seat adapted to engage said compliant check valve ball and a lead-in portion adjacent the ball seat for selectively guiding the check ball relative to the ball seat during use of said pump.   
   
   
       15 . The pump according to  claim 14  wherein said lead-in portion includes a tapered surface defining an angle of incidence with said longitudinal axis of about 30 degrees. 
   
   
       16 . The pump according to  claim 14  wherein said lead-in portion is integral with said fitting. 
   
   
       17 . The pump according to  claim 16  wherein said lead-in portion includes a tapered surface defining an angle of incidence with said longitudinal axis of about 30 degrees.