Hydraulic hand pump

Abstract

A method and apparatus is provided that includes a hand pump having a handle locking mechanism, a counter bored nut, pivoting links, and unlocking valve assembly. The unloading valve assembly allows a pump operator to pump a larger volume of hydraulic fluid and/or to pump to higher pressures in first stage operation than a conventional pump which employs a direct-acting relief valve. The unloading valve also decreases the effort required to pump the handle during second stage operation. The handle locking mechanism allows the pump handle from moving during transporting and storing of the hand pump. The counter bored nut allows for more reservoir room than conventional hand pumps. The pivoting link allows for greater leverage of the handle during pumping.

1 . An unloading valve assembly for a hand pump, comprising: 
 a back flow check valve that prevents fluid or air from a fluid reservoir from entering a piston chamber;    a first passage in communication with the back flow check valve and a second passage; and    an unloading valve having a ball that interacts with an actuator, wherein the actuator can move the ball in a first direction when pressure is asserted on the actuator.    
   
   
       2 . The hand pump of  claim 1 , wherein the actuator is moved in the first direction by fluid pressure supplied by the pump outlet.  
   
   
       3 . The hand pump of  claim 1 , wherein when the ball is moved in the first direction, fluid from the piston chamber is allowed to return to the fluid reservoir.  
   
   
       4 . The hand pump of  claim 1 , wherein the unloading valve allows fluid from a low pressure piston chamber to return to the fluid reservoir during a stage of pumping.  
   
   
       5 . The hand pump of  claim 1 , wherein the unloading valve can be a pilot operated dump valve.  
   
   
       6 . The hand pump of  claim 1 , wherein the ball can be a valve poppet.  
   
   
       7 . The hand pump of  claim 1 , wherein the unloading valve opens during a stage of pumping.  
   
   
       8 . A method of pumping a hand pump with an unloading valve assembly, comprising: 
 lifting a low pressure piston and a high pressure piston to draw fluid into a low pressure piston chamber and a high pressure piston chamber during a first stage of pumping;    moving fluid from the low and high pressure piston chambers to a pump outlet during a first stage of pumping;    opening the unloading valve assembly at a predetermined pressure during a subsequent stage of pumping; and    returning fluid from the low pressure piston chamber through the unloading valve assembly at the predetermined pressure during the subsequent stage.    
   
   
       9 . The method of pumping of  claim 8 , wherein the unloading assembly comprises: 
 a back flow check valve that prevents fluid or air from a fluid reservoir from entering a piston chamber;    a first passage in communication with the back flow check valve and a second passage; and    an unloading valve having a ball that interacts with an actuator, wherein the actuator can move the ball in a first direction when pressure is asserted on the actuator.    
   
   
       10 . The method of pumping of  claim 8 , wherein the predetermined pressure can be between about 700 p.s.i to about 1200 p.s.i.  
   
   
       11 . The method of pumping of  claim 8 , wherein when the pressure from the pump outlet is at the predetermined pressure, the unloading valve opens.  
   
   
       12 . The method of pumping  claim 8 , wherein the first stage of pumping, the fluid from the low and high pressure chambers are directed to the pump outlet.  
   
   
       13 . A hand pump with unloading system, comprising: 
 a means for preventing back flow that prevents fluid or air from a fluid reservoir from entering a piston chamber;    a first passage means in communication with the means for preventing back flow and a second passage means; and    a means for unloading having a ball valve that interacts with a means for actuating, wherein the means for actuating can move the ball valve in a first direction.    
   
   
       14 . The hand pump system of  claim 13 , wherein the means for actuating is moved in the first direction by fluid pressure supplied by a pump outlet.  
   
   
       15 . The hand pump system of  claim 13 , wherein when the ball valve is moved in the first direction, fluid from the piston chamber is allowed to return to the fluid reservoir.  
   
   
       16 . The hand pump system of  claim 13 , wherein the unloading valve allows fluid from a low pressure piston chamber to return to the fluid reservoir during a stage of pumping.  
   
   
       17 . The hand pump system of  claim 13 , wherein the means for unloading is a pilot operated dump valve.  
   
   
       18 . The hand pump system of  claim 13 , wherein the ball can be a valve poppet.  
   
   
       19 . The hand pump system of  claim 13 , wherein means for unloading operates during a subsequent stage of pumping.  
   
   
       20 . The hand pump system of  claim 13 , wherein during the second stage, the means for unloading can open at about 700 to 1200 p.s.i.