Patent US3722547A successfully refreshed from Google Patents.
US3722547A
Expired / Lapsed
US
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Pilot valve
Assignee: Jos Schneider Optische Werke GmbH
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Filing: 1971-10-18
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Granted: 1973-03-27
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Expires: 1991-10-18
Abstract
Abstract The working piston of a pilot valve has an extremity formed with an axial bore which receives a pilot piston with two or three heads defining one or two peripheral recesses included in a throttled path for the controlled admission of high-pressure fluid to a peripheral shoulder on that extremity. An oblique passage, forming part of that fluid path, extends in the region of the peripheral shoulder within the body of the working piston. The selected position of the working piston is maintained by countervailing fluid pressure acting upon a land of this piston, the effective area of that land being half that of the peripheral shoulder which in a state of balance is subjected to half the countervailing fluid pressure.
Inventors
- 👤 L Kirstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:16
CPC Classifications
F; F15; F15B; F15B13/00; F15B13/02; F15B13/04; F15B13/0401; F15B13/0402; Y; Y10; Y10T; Y10T137/00; Y10T137/8593; Y10T137/86493; Y10T137/86574; Y10T137/86582; Y10T137/86606
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
185 words
A pilot valve comprising: a cylindrical housing provided with a channel system for the flow of a working fluid to a load; a main piston axially movable in said housing for selectively blocking and unblocking the flow of said working fluid, said main piston having an extremity provided with an axial bore and with an external peripheral shoulder in the region of said bore; sealing means in said housing bearing upon a reduced portion of said extremity and defining a fluid chamber with said shoulder; a pilot piston axially slidable in said bore, said pilot piston being provided with a plurality of heads defining at least one peripheral recess included in a throttled path extending between a high-pressure port and a low-pressure port with a branch terminating at said fluid chamber for exerting upon said shoulder a fractional fluid pressure controlled by the relative position of said pistons, said path including an oblique passage in said extremity communicating with said recess and terminating at opposite sides of a transverse plane through said shoulder; and biasing means tending to immobilize said main piston in said housing.
Claim 2
Dependent Claim
185 words
A pilot valve comprising: a cylindrical housing provided with a channel system for the flow of a working fluid to a load; a main piston axially movable in said housing for selectively blocking and unblocking the flow of said working fluid, said main piston having an extremity provided with an axial bore and with an external peripheral shoulder in the region of said bore; sealing means in said housing bearing upon a reduced portion of said extremity and defining a fluid chamber with said shoulder; a pilot piston axially slidable in said bore, said pilot piston being provided with a plurality of heads defining at least one peripheral recess included in a throttled path extending between a high-pressure port and a low-pressure port with a branch terminating at said fluid chamber for exerting upon said shoulder a fractional fluid pressure controlled by the relative position of said pistons, said path including an oblique passage in said extremity communicating with said recess and terminating at opposite sides of a transverse plane through said shoulder; and biasing means tending to immobilize said main piston in said housing.
Claim 3
Dependent Claim
40 words
A pilot valve as defined in claim 1 wherein said biasing means comprises a land on said piston facing in a direction opposite that of said shoulder, said land being subjected to a countervailing fluid pressure from said high-pressure port.
Claim 4
Dependent Claim
37 words
A pilot valve as defined in claim 2 wherein the effective area of said land is half that of said shoulder, said fractional fluid pressure being half said countervailing fluid pressure in a state of fluidic balance.
Claim 5
Dependent Claim
83 words
A pilot valve as defined in claim 3 wherein said pilot piston has three axially spaced heads defining between them a first recess and a second recess, said first recess being open toward said passage and communicating therethrough with said high-pressure port, said second recess communicating with said low-pressure port, said branch being a radial bore in said extremity confronting the middle one of said heads and defining two narrow clearances on opposite sides thereof in a normal relative position of said pistons.
Claim 6
Dependent Claim
36 words
A pilot valve as defined in claim 4 wherein said first recess is surrounded by said reduced portion of said extremity, said passage terminating at an enlarged portion separated by said shoulder from said reduced portion.
Claim 7
Dependent Claim
52 words
A pilot valve as defined in claim 3 wherein said pilot piston has two axially spaced heads bounding said recess, said branch being constituted by said passage, said recess normally communicating with said ports via two radial bores in said extremity partly obstructed by said heads with formation of two narrow clearances.
Claim 8
Dependent Claim
28 words
A pilot valve as defined in claim 6 wherein said radial bores terminate at an enlarged portion of said extremity separated by said shoulder from said reduced portion.
Claim 9
Dependent Claim
28 words
A pilot valve as defined in claim 1 wherein said pilot piston has a throughgoing channel for equalizing the pressure in said axial bore at opposite ends thereof.
Claim 10
Dependent Claim
32 words
A pilot valve as defined in claim 1, further comprising a guide sleeve in said housing surrounding said main piston, said sleeve being provided with apertures forming part of said channel system.
Claim 11
Dependent Claim
29 words
A pilot valve as defined in claim 9, further comprising adjustable abutment means for said sleeve and resilient means axially urging said sleeve into contact with said abutment means.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |