Patent ID: 7234298
Filing Date: 2007-06-26
Classification: E02F,F15B

Abstract:
1. A hydraulic system comprising: at least one hydraulic cylinder including a first port and a second port; a first fluid passage connecting said first and second ports; a first hydraulic pump, which is a bi-directional pump, disposed within said first fluid passage, said first fluid passage including a first portion between said first pump and said first port and a second portion between said first pump and said second port; a second fluid passage connected with said first fluid passage; a second hydraulic pump in parallel with said first pump and disposed within said second fluid passage; an accumulator fluidly connected with said second fluid passage; a fluid supply separate from said accumulator and configured to supply a fluid to each of the first and second portions of said first fluid passage; and a valve configured to selectively connect said fluid supply with one of the first and second portions of said first fluid passage based at least in part on a pressure difference between said first and second portions, said valve having a first position at which said fluid supply connects with the first portion but not the second portion of said first fluid passage, and a second position at which said fluid supply connects with the second portion but not the first portion of said first fluid passage.