Patent US3773028A successfully refreshed from Google Patents.
US3773028A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motorized damper operator and control
Assignee: Cutler Hammer Inc
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Filing: 1971-12-09
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Granted: 1973-11-20
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Expires: 1991-12-09
Abstract
Abstract An electric motor driven operator and control for dampers of the gravity return type, such as used in chimney flues for fireplaces. The operator comprises an electric motor-gear speed reduction unit for driving a crank arm which engages with a pivoted member in an elongated slot in the latter. In each revolution of the output shaft of the driving unit the pivoted member opens the damper in the first half revolution, and then allows it to close in the remaining half revolution. The control comprises a two position selector switch, and limit switch operable in accordance with the motor shaft position to cause the motor to stop when the damper is in full open position, or when in completely closed position. Indicating lights are provided to indicate when the damper is in open position, and when the temperature in the region of the damper operator exceeds a predetermined high limit.
Inventors
- 👤 J Schreibeis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:03
CPC Classifications
F; F23; F23N; F23N3/00; F23N3/08; F23N3/085; F23N2235/00; F23N2235/02; F23N2235/04; F23N2235/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
208 words
The combination with a pivoted, gravity return type damper in a chimney flue and means operable to open said damper and when said damper is open to allow it to close under gravity bias comprising: a. a member mounted for pivoted movement and engagable with said damper, said member having an elongated slot formed therein, b. an electric motor-gear speed reducing unit having an output shaft, c. a crank arm secured to said output shaft and having a portion engaging said member within said slot, and d. control means comprising a selector switch operable to one position when said damper is in closed position to energize said motor and thereby rotate said crank arm and pivot said member in a given direction to open said damper And further comprising switch means operable when said damper reaches full open position to deenergize said motor, said selector switch being operable to another position when said damper is fully open to energize said motor to rotate said crank arm further in the same direction and pivot said member in an opposite direction away from said damper to allow the latter to close under gravity bias, and said switch means also operating when said damper reaches closed position to deenergize said motor.
Claim 2
Dependent Claim
208 words
The combination with a pivoted, gravity return type damper in a chimney flue and means operable to open said damper and when said damper is open to allow it to close under gravity bias comprising: a. a member mounted for pivoted movement and engagable with said damper, said member having an elongated slot formed therein, b. an electric motor-gear speed reducing unit having an output shaft, c. a crank arm secured to said output shaft and having a portion engaging said member within said slot, and d. control means comprising a selector switch operable to one position when said damper is in closed position to energize said motor and thereby rotate said crank arm and pivot said member in a given direction to open said damper And further comprising switch means operable when said damper reaches full open position to deenergize said motor, said selector switch being operable to another position when said damper is fully open to energize said motor to rotate said crank arm further in the same direction and pivot said member in an opposite direction away from said damper to allow the latter to close under gravity bias, and said switch means also operating when said damper reaches closed position to deenergize said motor.
Claim 3
Dependent Claim
27 words
The combination according to claim 1 wherein said control means further includes an indicating lamp which is energized whenever said selector switch is in said one position.
Claim 4
Dependent Claim
59 words
The combination according to claim 2, wherein said control means also includes a second indicating lamp and a thermally responsive switch in circuit therewith for mounting in the chimney flue in proximity to the damper driving unit, said thermally responsive switch closing to energize said second indicating lamp whenever it is subjected to temperatures above a predetermined high limit.
Claim 5
Dependent Claim
64 words
The combination according to claim 1 wherein said switch means comprises a limit switch in circuit with said selector switch, and a cam driven by said output shaft, said cam having a circumferential cam surface such that said limit switch assumes one operating condition during one-half revolution of the output shaft, and another operating condition for the remaining portion of each output shaft revolution.
Claim 6
Dependent Claim
43 words
The combination according to claim 1 wherein said member is L-shaped and the slot is in the leg which is pivoted and wherein the other leg of said member has a roller rotatably mounted adjacent its free end which engages with said damper.
Claim 7
Dependent Claim
67 words
The combination according to claim 4 wherein said motor gear speed reducing unit, said crank arm, said member mounted for pivotal movement, and said switch means when mounted in a chimney flue are provided with a partially enclosing duct having an entrance extending into the fireplace opening to convey relatively cool air up and around such elements whenever said damper is open to afford chimney drawing action.
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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) | 1976-11-19 | 1977-05-21 | 1977-11-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-19 | 1981-05-21 | 1981-11-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-19 | 1985-05-21 | 1985-11-20 | $7700.00 | Window Closed / Lapsed |