US3875612A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Door control device
Assignee: Kidde Inc
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Filing: 1972-10-05
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Granted: 1975-04-08
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Expires: 1992-10-05
Abstract
Abstract Disclosed is a control mechanism having a spring that urges a piston in a closing direction. In response to movement of the piston in the opening direction, a check valve allows flow of hydraulic fluid from a reservoir volume into a hold volume where it is retained to prevent return movement of the piston in the closing direction under the influence of the spring bias. A door coupled to the piston can be urged into any open position and is retained there by the fluid in the hold volume. Disposed within another passage between the reservoir and hold volumes is a control valve that is biased in a closed position by a valve biasing leaf spring. A control surface on a stem of the valve is subjected to the fluid pressure in the hold volume and exerts a force in opposition to the control valve bias. In response to exertion on the piston of a force complementing the closure force provided by the spring bias, increased fluid pressure in the hold volume overcomes the control valve bias allowing the valve to open and permitting hydraulic fluid flow from the hold volume into the reservoir volume. Consequently, a door connected to the closure device can be manually moved from any retained position in a closing direction. A second control mechanism responds to a predetermined condition by reducing the valve control valve bias also resulting in fluid flow between the hold and reservoir volumes and enabling the coil spring to force the piston and associated door in a closing direction.
Inventors
- 👤 Edward J Poitras
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 01:47
CPC Classifications
E; E05; E05F; E05F3/00; E05F3/04; E05F3/10; E05F3/102; A; A62; A62C; A62C2/00; A62C2/06; A62C2/12; E05F3/22; E05F3/223; E05Y; E05Y2900/00; E05Y2900/10; E05Y2900/13; E05Y2900/132
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
288 words
An hydraulic door closer comprising a housing defining a chamber for hydraulic fluid; a piston mounted within said housing and dividing said chamber into reservoir and hold volumes, said piston adapted for reciprocating movement through said chamber in opening and closing directions; connecting means for coupling movement of said piston with a door; piston bias means exerting a closure force tending to move said piston in said closing direction; check valve means which opens to allow flow of the hydraulic fluid from said reservoir volume to said hold volume in response to movement of said piston in said opening direction and closes in the absence of movement in said opening direction to trap hydraulic fluid in said hold volume; a control valve disposed within a fluid flow passage extending between said reservoir and hold volume; valve bias means biasing said control valve in a closed position to prevent fluid flow through said passage and thereby prevent closing movement of the door; first control means for overcoming said valve bias means to open said control valve to effect closing movement of the door in response to exertion on said piston of an auxiliary force aiding said closure force; second control means actuatable to reduce said valve bias means and open said control valve to effect closing movement of the door in response to a predetermined condition; and trip means for automatically reducing said valve bias independently of actuation of said second control means to maintain said control valve in an open condition with said piston located in a predetermined range of positions within said chamber so as to prevent retention of the door in a range of open positions corresponding to said predetermined range of positions of said piston.
Claim 2
Dependent Claim
288 words
An hydraulic door closer comprising a housing defining a chamber for hydraulic fluid; a piston mounted within said housing and dividing said chamber into reservoir and hold volumes, said piston adapted for reciprocating movement through said chamber in opening and closing directions; connecting means for coupling movement of said piston with a door; piston bias means exerting a closure force tending to move said piston in said closing direction; check valve means which opens to allow flow of the hydraulic fluid from said reservoir volume to said hold volume in response to movement of said piston in said opening direction and closes in the absence of movement in said opening direction to trap hydraulic fluid in said hold volume; a control valve disposed within a fluid flow passage extending between said reservoir and hold volume; valve bias means biasing said control valve in a closed position to prevent fluid flow through said passage and thereby prevent closing movement of the door; first control means for overcoming said valve bias means to open said control valve to effect closing movement of the door in response to exertion on said piston of an auxiliary force aiding said closure force; second control means actuatable to reduce said valve bias means and open said control valve to effect closing movement of the door in response to a predetermined condition; and trip means for automatically reducing said valve bias independently of actuation of said second control means to maintain said control valve in an open condition with said piston located in a predetermined range of positions within said chamber so as to prevent retention of the door in a range of open positions corresponding to said predetermined range of positions of said piston.
Claim 3
Dependent Claim
31 words
An hydraulic door closer according to claim 1 wherein said predetermined range of positions of said piston correspond only to positions of the door within a few degrees of fully closed.
Claim 4
Dependent Claim
41 words
An hydraulic door closer according to claim 1 wherein said first control means comprises relief means for overcoming said valve bias in response to a greater fluid pressure in said hold volume than that normally provided by said piston bias means.
Claim 5
Dependent Claim
50 words
An hydraulic door closer according to claim 3 wherein said relief means comprises a surface exposed to the fluid pressure in said hold volume and coupled for movement with said control valve, said surface being disposed to provide a fluid pressure induced force in opposition to said valve bias means.
Claim 6
Dependent Claim
21 words
An hydraulic door closer according to claim 4 including fluid flow restriction means between said hold volume and said control valve.
Claim 7
Dependent Claim
29 words
An hydraulic door closer according to claim 5 wherein said restriction means comprises adjustable restriction means for adjusting the fluid conductance between said hold volume and said control valve.
Claim 8
Dependent Claim
41 words
An hydraulic door closer according to claim 1 wherein said second control means comprises actuator means coupled to said valve bias means and adapted to reduce the biasing force applied thereby to said control valve in response to said predetermined condition.
Claim 9
Dependent Claim
29 words
An hydraulic door closer according to claim 7 wherein said actuator means comprises an electrical solenoid having a coil and an armature and said predetermined condition is deenergization thereof.
Claim 10
Dependent Claim
39 words
An hydraulic door closer according to claim 8 wherein said control valve comprises a valve seat defined by said passage, a valve stem movable in said passage and including a head portion disposed to seat against said valve seat.
Claim 11
Dependent Claim
53 words
An hydraulic door closer according to claim 9 wherein said valve bias means comprises a leaf spring having one end fixed to said housing, an opposite end engaged on one side by said armature, and an intermediate portion with a side opposite said one side exerting said biasing force on said control valve.
Claim 12
Dependent Claim
25 words
An hydraulic door closer according to claim 10 including adjustment means for adjusting the biasing force applied to said control valve by said leaf spring.
Claim 13
Dependent Claim
28 words
An hydraulic door closer according to claim 11 wherein said adjustment means comprises a screw threaded through said intermediate portion and having an end engaging said valve stem.
Claim 14
Dependent Claim
44 words
An hydraulic door closer according to claim 12 wherein said trip means comprises trip actuator means for automatically reducing the biasing force applied by said valve bias means in response to location of said piston in said predetermined range of positions within said chamber.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |