Hydrostatic pump assembly having symmetrical endcap

Abstract

A hydrostatic pump assembly having a casing which encloses a pumping mechanism, and including a housing, and an endcap attached to the housing. The endcap has at least one lateral exterior surface, and a first system fluid passage having a pair of system ports located in the endcap lateral exterior surface, and a second system fluid passage having a pair of system ports located in the endcap lateral exterior surface, each of the first and second system fluid passages being in fluid communication with the pumping mechanism. In one embodiment, the pair of system ports of the first system fluid passage are located opposite each other in the endcap lateral exterior surface. The pair of system ports of the second system fluid passage may also be located opposite each other in the endcap lateral exterior surface.

What is claimed is:  
     
         1 . An endcap for a hydrostatic pump, comprising: 
 an endcap housing; and    a pair of system passages formed in said endcap housing, each said system passage fluidly connected to the hydrostatic pump, each said system passage fluidly connected to a pair of system ports formed in an exterior of said endcap housing.    
     
     
         2 . The endcap of  claim 1 , further comprising: 
 a bypass passage fluidly connecting said pair of system passages, said bypass passage having a first end and a second end, each of said first and said second ends forming a valve seat.    
     
     
         3 . The endcap of  claim 2 , further comprising: 
 a pair of bypass valve holes formed in said exterior of said endcap housing, each of said pair of bypass valve holes providing access to one of said valve seats.    
     
     
         4 . The endcap of  claim 3 , wherein said pair of bypass valve holes are formed in a pair of opposing bypass passage sides of said endcap housing, and each said pair of system ports are formed in opposing system passage sides of said endcap housing.  
     
     
         5 . The endcap of  claim 3 , wherein each said bypass valve hole is aligned with one of said valve seats.  
     
     
         6 . The endcap of  claim 3 , further comprising: 
 a bypass valve seated on one of said valve seats, whereby said pair of system passages are no longer fluidly connected, said bypass valve positioned in one of said bypass valve holes and secured to said endcap housing.    
     
     
         7 . An endcap for a hydrostatic pump, comprising: 
 an endcap housing; and    system passage means for providing a pair of fluid accesses to the hydrostatic pump from a pair of system passage sides of said endcap housing.    
     
     
         8 . The endcap of  claim 1 , further comprising: 
 a bypass passage fluidly connecting said pair of fluid accesses, said bypass passage having a first end and a second end, each of said first and said second ends forming a valve seat.    
     
     
         9 . The endcap of  claim 8 , further comprising: 
 a pair of bypass valve holes formed in a pair of opposing bypass passage sides of said endcap housing, each of said pair of bypass valve holes providing access to one of said valve seats.    
     
     
         10 . The endcap of  claim 8 , wherein said bypass passage sides comprise opposing sides of said endcap housing and said system passage sides comprise opposing sides of said endcap housing.  
     
     
         11 . The endcap of  claim 9 , wherein each said bypass valve hole is aligned with one of said valve seats.  
     
     
         12 . The endcap of  claim 8 , further comprising: 
 a bypass valve seated on one of said valve seats, whereby said pair of system passages are no longer fluidly connected, said bypass valve positioned in one of said bypass valve holes and secured to said endcap housing.    
     
     
         13 . An endcap for a hydrostatic pump, comprising: 
 an endcap housing;    a pair of system passages formed in said endcap housing, each said system passage fluidly connected to the hydrostatic pump; and    a bypass passage fluidly connecting said pair of system passages, said bypass passage having a first end and a second end, each of said first and said second ends forming a valve seat.    
     
     
         14 . The endcap of  claim 13 , further comprising: 
 a pair of bypass valve holes formed in a pair of opposing bypass passage sides of said endcap housing, each of said pair of bypass valve holes providing access to one of said valve seats.    
     
     
         15 . The endcap of  claim 14 , wherein each said bypass valve hole is aligned with one of said valve seats.  
     
     
         16 . The endcap of  claim 14 , further comprising: 
 a bypass valve seated on one of said valve seats, whereby said pair of system passages are no longer fluidly connected, said bypass valve positioned in one of said bypass valve holes and secured to said endcap housing.    
     
     
         17 . A hydrostatic pump assembly comprising: 
 a casing;    a pumping mechanism, said casing enclosing said pumping mechanism, said casing comprising: 
 a housing; and  
 an endcap attached to said housing, said endcap having at least one lateral exterior surface, and a first system fluid passage having a pair of system ports located opposite each other in said endcap lateral exterior surface, and a second system fluid passage having a pair of system ports located opposite each other in said endcap lateral exterior surface, said first and second system fluid passages in fluid communication with said pumping mechanism.  
   
     
     
         18 . The hydrostatic pump assembly of  claim 17 , wherein said endcap lateral exterior surface is formed by four connected lateral sides, opposing said system ports of each said pair of system ports being located in opposite ones of said four lateral sides.  
     
     
         19 . The hydrostatic pump assembly of  claim 17 , wherein one said system port of each said pair of system ports is selectively plugged.  
     
     
         20 . The hydrostatic pump assembly of  claim 17 , wherein said endcap has a bypass passage extending between said first and said second system fluid passages, said bypass passage in communication with a pair of bypass valve holes located opposite each other in said endcap lateral exterior surface, said hydrostatic pump assembly further comprising: 
 a bypass valve located in one of said pair of bypass valve holes, said bypass valve interchangeable between said pair of bypass holes; and    a removable plug located in the other of said pair of bypass valve holes, said bypass passage being selectively opened and closed by said bypass valve, whereby said first and said second system fluid passages may be placed in and out of direct fluid communication with each other through said bypass passage.    
     
     
         21 . The hydrostatic pump assembly of  claim 17 , wherein said pump assembly is provided with a pair of selectively closeable case drains located opposite each other in said housing,