Piston assembly for hydraulic pump

Abstract

A method of assembling a piston and shoe of a hydraulic pump. The method includes: inserting a shaft of the piston through an aperture of the shoe such that it extends through to the other side until a piston head of the piston is seated in the shoe. A piston and shoe assembly for a hydraulic pump. The assembly includes: a piston comprising a piston shaft and a piston head; and a shoe comprising an aperture, wherein the piston shaft is sized such that it can pass through the shoe aperture and the piston head is sized such that it cannot pass through the shoe aperture.

1 . A method of assembling a piston having a shaft and of a hydraulic pump, the method comprising:
 inserting a shaft of the piston through an aperture of the shoe such that it extends through the shoe until a piston head of the piston is seated in the shoe.   
     
     
         2 . The method according to  claim 1 , comprising
 inserting a plug into the shoe such that the piston head is held between the shoe and the plug.   
     
     
         3 . The method according to  claim 1 , comprising
 installing a piston sleeve onto the shaft of the piston.   
     
     
         4 . The method according to  claim 3 , comprising
 installing a fixing into the piston and piston sleeve to secure the piston and piston sleeve together.   
     
     
         5 . The method according to  claim 4 , wherein the piston sleeve is a first piston sleeve and the method comprises:
 removing the fixing from the piston and first piston sleeve;   removing the first piston sleeve from the shaft of the piston; and   installing a second piston sleeve onto the shaft of the piston.   
     
     
         6 . The method according to  claim 5 , wherein the second piston sleeve is of a greater cross section than the first piston sleeve, or wherein the second piston sleeve is of a smaller cross section than the first piston sleeve. 
     
     
         7 . A method of disassembling a piston and shoe of a hydraulic pump, the method comprising:
 passing a shaft of the piston through an aperture of the shoe to thereby decouple a piston head of the piston from the shoe.   
     
     
         8 . A piston and shoe assembly for a hydraulic pump, the assembly comprising:
 a piston comprising a piston shaft and a piston head; and   a shoe comprising an aperture,   wherein the piston shaft is sized such that it can pass through the shoe aperture and the piston head is sized such that it cannot pass through the shoe aperture.   
     
     
         9 . The piston and shoe assembly according to  claim 8 , comprising a plug at least partially located within the shoe and arranged to hold the piston head in the shoe. 
     
     
         10 . The piston and shoe assembly according to any of  claim 8 , comprising:
 a piston sleeve along the piston shaft.   
     
     
         11 . The piston and shoe assembly of  claim 10 , comprising a fixing arranged to secure the piston sleeve to the piston shaft. 
     
     
         12 . The piston and shoe assembly according to  claim 9 , wherein the piston comprises a piston inner passageway and the plug comprises a plug inner passageway, the piston inner passageway and plug inner passageway arranged in fluid communication. 
     
     
         13 . The piston and shoe assembly according to  claim 12 , wherein the plug inner passageway comprises an enlarged opening for receiving fluid communication from the piston inner passageway. 
     
     
         14 . The piston and shoe assembly according to  claim 8 ,
 wherein the piston head comprises a spherical portion, the piston shaft has a circular cross-section and the shoe aperture is of circular cross-section, and   wherein the diameter of the spherical portion of the piston head is greater than the diameter of the piston shaft and the shoe aperture has a diameter that is greater than the diameter of the piston shaft and smaller than the diameter of the piston head.   
     
     
         15 . A hydraulic pump comprising:
 the piston and shoe assembly according to  claim 8 .