US3628567A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Power control valve
Assignee: TDK Micronas GmbH
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Filing: 1970-06-15
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Granted: 1971-12-21
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Expires: 1990-06-15
Abstract
Abstract A two-stage hydraulic valve system for controlling a doubleacting load the system having a three-position first stage valve for supplying pressure medium to pressure chambers on either end of a piston valve slide in a power control valve having twin lift valves for connecting the pressure source to the double-acting load. The lift valves, which are in the ends of the piston valve cylinder connect the load to the pressure chambers when the valves are opened, either by the movement of the piston valve slide against the lift valve, or by the increased pressure in the pressure chamber when the valve slide is at one end of its stroke and the pump pressure is applied to the pressure chamber at the other end of the valve slide. In the neutral position of the power valve there is free circulation of pressure medium from the source to the reservoir through a pressurizing valve. This circulation is cut off when the valve is actuated and the full pump pressure applied to one of the pressure chambers by means of valving passages and ports in the cylinder and slide.
Inventors
- 👤 Alfred Bender
- 👤 Horst A Hornig
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:41
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/02; F15B13/04; F15B13/0401; F15B13/0402; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/87169; Y10T137/87177; Y10T137/87185; Y10T137/87233; Y10T137/87241
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
203 words
A servo valve comprising; a housing having a closed cylinder therein with axially spaced supply and discharge ports in the cylinder wall, a double-acting piston in the cylinder forming a pair of pressure chambers one between each end of the piston and an end of the cylinder, a pair of normally closed lift valves one in each end of the cylinder, each valve connecting one of the pressure chambers to a load passage, means on each end of the piston for opening one of the valves as the piston approaches the end of the cylinder, a pair of passages in the piston, each passage leading from one pressure chamber to an opening in the piston wall, the passage openings being axially spaced from each other, means for holding the piston in a neutral position intermediate the ends of the cylinder in which the passage openings in the piston are each positioned between a discharge port means which is nearer to the pressure chamber to which the passage is connected and a supply port means which is further from the pressure chamber, each passage opening being spaced the same distance from its supply port means and the same distance from its discharge port means.
Claim 2
Dependent Claim
203 words
A servo valve comprising; a housing having a closed cylinder therein with axially spaced supply and discharge ports in the cylinder wall, a double-acting piston in the cylinder forming a pair of pressure chambers one between each end of the piston and an end of the cylinder, a pair of normally closed lift valves one in each end of the cylinder, each valve connecting one of the pressure chambers to a load passage, means on each end of the piston for opening one of the valves as the piston approaches the end of the cylinder, a pair of passages in the piston, each passage leading from one pressure chamber to an opening in the piston wall, the passage openings being axially spaced from each other, means for holding the piston in a neutral position intermediate the ends of the cylinder in which the passage openings in the piston are each positioned between a discharge port means which is nearer to the pressure chamber to which the passage is connected and a supply port means which is further from the pressure chamber, each passage opening being spaced the same distance from its supply port means and the same distance from its discharge port means.
Claim 3
Dependent Claim
38 words
The valve of claim 1 wherein the mean on each end of the piston for opening the lift valve is an axially extending stud adapted to lift the valve before the piston abuts against the cylinder end wall.
Claim 4
Dependent Claim
39 words
The valve of claim 2 including recirculating means comprising a passage in the pisTon connecting the supply port means to the discharge port means in the neutral position of the valve and a spring-loaded check valve in said passage.
Claim 5
Dependent Claim
18 words
The valve of claim 3 wherein the ports in the cylinder are annular grooves in the cylinder wall.
Claim 6
Dependent Claim
58 words
The valve of claim 3 wherein the means for holding the piston in the neutral position comprise compression springs in each pressure chamber acting between the end of the cylinder and the piston to bias the piston toward the neutral position and abutments in the cylinder for limiting the spring force on the piston in the neutral position.
Claim 7
Dependent Claim
35 words
A valve system comprising a plurality of valves as defined in claim 1 connected in series with the discharge port means of the preceding valve connected to the supply port means of the next valve.
Claim 8
Dependent Claim
39 words
The valve of claim 1 including recirculating means comprising a passage in the piston connecting the supply port means to the discharge port means in the neutral position of the valve and a spring-loaded check valve in said passage.
Claim 9
Dependent Claim
18 words
The valve of claim 1 wherein the ports in the cylinder are annular grooves in the cylinder wall.
Claim 10
Dependent Claim
58 words
The valve of claim 1 wherein the mean for holding the piston in the neutral position comprise compression springs in each pressure chamber acting between the end of the cylinder and the piston to bias the piston toward the neutral position and abutments in the cylinder for limiting the spring force on the piston in the neutral position.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-12-20 | 1975-06-21 | 1975-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-12-20 | 1979-06-21 | 1979-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-12-20 | 1983-06-21 | 1983-12-21 | $7700.00 | Window Closed / Lapsed |