US3574886A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Position control hydraulic snubber
Assignee: NI West Inc
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Filing: 1969-07-10
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Granted: 1971-04-13
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Expires: 1989-07-10
Abstract
Abstract A hydraulic snubber for such use as a door closer in which a main piston connected to an actuator arm slides in a main chamber containing a bypass which, once passed, allows hydraulic liquid to be trapped ahead of the main piston and then actuate a control piston which is reciprocated in a control chamber. From the control chamber there are paths through which hydraulic fluid can flow to a reservoir. One path is an unrestricted passage and the other path is a restricted passage. During part of the movement cycle of the control piston, the hydraulic fluid flows freely through the unrestricted passage until a valve element carried by a separate resiliently mounted shutoff piston closes the unrestricted passage. At this point hydraulic fluid is forced through the restricted passage to the reservoir and retards movement of the control piston, which continues to move relative to the shutoff piston because of the resilient connection between them. Movement of the control piston finally stops when it bottoms against the stationary end of the control chamber. Upon the return cycle, hydraulic fluid first flows freely from the reservoir through the check valve passage to the control chamber while the shutoff valve remains closed and later, when the shutoff valve is opened, the hydraulic liquid also flows freely from the reservoir through the corresponding passage and shutoff valve seat into the control chamber.
Inventors
- 👤 George B Solovieff
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 14:56
CPC Classifications
E; E05; E05F; E05F3/00; E05F3/04; E05F3/10; E05F3/102; E05F3/12
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
255 words
A position-control hydraulic snubber comprising a housing having a main chamber and a control chamber therein, a main piston slidably mounted in said main chamber, a control piston slidably mounted adjacent one end of said control chamber and in hydraulic communication with said main chamber and a closure structure closing the other end of said control chamber, an actuator operably connected to said main piston for moving said main piston within said main chamber, a bypass passage around said main piston having a port intermediate opposite ends of said main chamber adapted to be closed by movement of said main piston to a corresponding intermediate position, a reservoir in said housing for hydraulic fluid and passage means interconnecting said reservoir with said control chamber, a shutoff stem reciprocatably mounted in said closure structure, said shutoff stem having an axial bore therethrough in communication with said control chamber, and an outwardly facing shutoff valve seat for said axial bore, said passage means comprising an unrestricted passage between said reservoir and said axial bore and a restricted passage between said reservoir and said control chamber, a shutoff piston reciprocatably mounted in said control piston and having a normally open outwardly facing shutoff valve element adapted to seat on said shutoff valve seat, and yieldable means acting between said shut-off piston and said control piston enabling movement of said control piston against fluid resistance created by said restricted passage after closure of said unrestricted passage by the seating of said shutoff valve element on said shutoff valve seat.
Claim 2
Dependent Claim
255 words
A position-control hydraulic snubber comprising a housing having a main chamber and a control chamber therein, a main piston slidably mounted in said main chamber, a control piston slidably mounted adjacent one end of said control chamber and in hydraulic communication with said main chamber and a closure structure closing the other end of said control chamber, an actuator operably connected to said main piston for moving said main piston within said main chamber, a bypass passage around said main piston having a port intermediate opposite ends of said main chamber adapted to be closed by movement of said main piston to a corresponding intermediate position, a reservoir in said housing for hydraulic fluid and passage means interconnecting said reservoir with said control chamber, a shutoff stem reciprocatably mounted in said closure structure, said shutoff stem having an axial bore therethrough in communication with said control chamber, and an outwardly facing shutoff valve seat for said axial bore, said passage means comprising an unrestricted passage between said reservoir and said axial bore and a restricted passage between said reservoir and said control chamber, a shutoff piston reciprocatably mounted in said control piston and having a normally open outwardly facing shutoff valve element adapted to seat on said shutoff valve seat, and yieldable means acting between said shut-off piston and said control piston enabling movement of said control piston against fluid resistance created by said restricted passage after closure of said unrestricted passage by the seating of said shutoff valve element on said shutoff valve seat.
Claim 3
Dependent Claim
52 words
A position control hydraulic snubber as in claim 1 wherein there is an adjusting means acting between said shutoff stem and said closure structure adapted to change the location of said shutoff valve seat whereby to vary the point where said actuator commences to be subject to control by said restricted passage.
Claim 4
Dependent Claim
23 words
A position-control hydraulic snubber as in claim 2 wherein there is access means in the housing from the exterior to said shutoff stem.
Claim 5
Dependent Claim
21 words
A position control hydraulic snubber as in claim 1 wherein there is an adjustable flow regulating valve in said restricted passage.
Claim 6
Dependent Claim
25 words
A position control hydraulic snubber as in claim 4 wherein there is access means in the housing from the exterior to said flow regulating valve.
Claim 7
Dependent Claim
19 words
A position control hydraulic snubber as in claim 1 wherein said chambers and said pistons are in axial alignment.
Claim 8
Dependent Claim
39 words
A position control hydraulic snubber as in claim 1 wherein there is a check valve passage means between said reservoir and said control chamber including a check valve acting to allow flow from said reservoir to said control chamber.
Claim 9
Dependent Claim
34 words
A position control hydraulic snubber as in claim 1 wherein there is spring means acting between said housing and respectively said control piston and said main piston for returning said pistons to initial position.
Claim 10
Dependent Claim
39 words
A position control hydraulic snubber as in claim 1 wherein said control piston has a position bottomed on said closure structure at a forward end of its stroke whereby to stop motion of said main piston and said actuator.
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) | 1974-04-12 | 1974-10-12 | 1975-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-12 | 1978-10-12 | 1979-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-12 | 1982-10-12 | 1983-04-13 | $7700.00 | Window Closed / Lapsed |