Patent ID: 6357231
Filing Date: 2002-03-19
Classification: E02F,F16H

Abstract:
A hydraulic circuit for driving motors for propelling a machine across the ground comprising first, second and third pumps providing fluid under pressure along first, second and third output lines, respectively, the first and second pumps being connected to drive separate vehicle propulsion motors, the third pump providing a flow of fluid to control valves for work elements on the machine, and through a normally open valve to drain, a pair of check valves connected to and preventing from the first output line of said first pump to the third pump and from the second output line of the second pump to the third pump, a coupling line from the normally open valve connected between the check valves, the normally open valve being moveable to block fluid flow from the third pump to drain and force fluid under pressure into the coupling line, said check valves opening to permit flow of fluid from the third pump through the check valves when the normally open valve moves to block fluid flow from the third pump to drain.