Control system with tri-pressure selector network
AssigneeCase Corporation
InventorDonnell L. Dunn
Life of this patent
Estimating the term…
Abstract
The invention is an improvement in a control system having first, second and third sources of fluid at differing pressures. The improvement comprises a tripath pressure selector network connected to the first and second sources. A pressure-sensing device connects the network and the third source when the third source is at a predetermined minimum pressure. The invention has particular utility in mobile construction machinery having, e.g., steering, implement and brake hydraulic circuits, at differing pressures. In one embodiment, the third source is a brake hydraulic circuit. The improvement helps assure that adequate pilot pressure is available for a "downstream" pilot control valve.
Claims4
In a control system having first, second and third sources of fluid at differing pressures, the improvement comprising:
- a tri-path pressure selector network connected to the first and second sources;
- and wherein:
- the third source includes first and second accumulators;
- and,
- a pressure-sensing device connects the network and the third source only when the second accumulator is at a pressure in excess of about 600 p.s.i.
In a control system having first, second and third sources of fluid at differing pressures, the improvement wherein:
- a tri-path pressure selector network is connected to the first and second sources;
- the third source includes first and second accumulators;
- and,
- a pressure-sensing device connects the network and the second accumulator when the second accumulator is at a predetermined pressure.
In a control system having first, second and third sources of fluid at differing pressures, the improvement comprising:
- a tri-path pressure selector network connected to the first and second sources;
- the third source and the pressure selector network are connected by a pressure line;
- a check valve is in the pressure line for preventing fluid from the first and second sources from flowing to the third source;
- a pressure-sensing sequence valve has a pilot signal line connected to the pressure line;
- the sequence valve connects the third source to the network when the third source is at a predetermined minimum pressure;
- the check valve is interposed between the pressure-sensing device and the third source;
- and,
- the pilot signal line is connected between the sequence valve and the check valve.
In a control system having first, second and third sources of fluid at differing pressures, the improvement comprising:
- a tri-path pressure selector network connected to the first and second sources;
- the third source and the pressure selector network are connected by a pressure line;
- a check valve is in the pressure line for preventing fluid from the first and second sources from flowing to the third source;
- a pressure-sensing sequence valve has a pilot signal line connected to the pressure line;
- the sequence valve connects the third source to the network when the third source is at a predetermined minimum pressure;
- the check valve is interposed between the pressure-sensing device and the third source;
- and,
- the pilot signal line is connected between the check valve and the third source.
Dependencies are inferred from the claim text.