Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
214 words
In a hydraulic steering system (10) having a pilot operated steering valve (24), a hand metering unit (31) in fluid communication with opposite ends of the steering valve (24), a followup servo cylinder (19), a pair of lines (51,52) connecting opposite ends of the servo cylinder (19) to opposite ends of the steering valve (24), the improvement comprising: a pair of pilot operated valves (53,54) individually positioned within the pair of lines (51,52) each being movable between a closed position at which fluid flow therethrough is blocked and an open position at which fluid can communicate between the servo cylinder (19) and the opposite ends of the steering valve (24), each of the pilot operated valves (53,54) being moved to the open position in response to fluid pressure in the pair of lines (51,52) reaching a preselected level and to the closed position in response to the fluid pressure in the lines (51,52) between the pilot operated valves (53,54) and the opposite ends of the servo cylinder being (19) less than the preselected level, and means (71) for establishing fluid pressure in the pair of lines (51,52) above the preselected level, said means (71) being connected to the lines (51,52) at a location between the pilot operated valves (53,54) and the servo cylinder (19).
Claim 2
Dependent Claim
214 words
In a hydraulic steering system (10) having a pilot operated steering valve (24), a hand metering unit (31) in fluid communication with opposite ends of the steering valve (24), a followup servo cylinder (19), a pair of lines (51,52) connecting opposite ends of the servo cylinder (19) to opposite ends of the steering valve (24), the improvement comprising: a pair of pilot operated valves (53,54) individually positioned within the pair of lines (51,52) each being movable between a closed position at which fluid flow therethrough is blocked and an open position at which fluid can communicate between the servo cylinder (19) and the opposite ends of the steering valve (24), each of the pilot operated valves (53,54) being moved to the open position in response to fluid pressure in the pair of lines (51,52) reaching a preselected level and to the closed position in response to the fluid pressure in the lines (51,52) between the pilot operated valves (53,54) and the opposite ends of the servo cylinder being (19) less than the preselected level, and means (71) for establishing fluid pressure in the pair of lines (51,52) above the preselected level, said means (71) being connected to the lines (51,52) at a location between the pilot operated valves (53,54) and the servo cylinder (19).
Claim 3
Dependent Claim
19 words
The hydraulic steering system (10) of claim 1 wherein the pilot operated valves (53,54) are pilot operated check valves.
Claim 4
Dependent Claim
36 words
The hydraulic steering system (10) of claim 2 including a pair of cross over valves (68,69) interconnecting the pair of lines (51,52) at a location between the pilot operated valves (53,54) and the servo cylinder (19).
Claim 5
Dependent Claim
52 words
The hydraulic steering system (10) of claim 3 including a pump (22) connected to the steering valve (24), and wherein said means (71) for establishing the preselected pressure level includes a pressure reducing valve (73) in fluid communication with the pump (22) and being connected to the first and second lines (51,52).