Patent US3788428A successfully refreshed from Google Patents.
US3788428A
Expired / Lapsed
US
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Elevator safety control circuit for preventing elevator door from opening at floor with fire
Assignee: UNIVERSAL TECHNOLOGY CORP A CORP OF DE
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Filing: 1972-12-22
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Granted: 1974-01-29
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Expires: 1992-12-22
Abstract
Abstract A sensor mounted on an elevator car senses the heat developed in the adjacent hallway as the car moves between the floors of a building. The heat sensor is connected to a relay circuit to operate a relay which prevents the car door from opening at any floor whenever excessive heat is sensed as a result of a fire in the hallway. That relay may also be employed to operate, when it is actuated in response to the detection of excessive heat, a fireman''s return circuit to recall the elevator car to the lobby floor, and to provide an indication at the lobby floor of the existence and location of the fire.
Inventors
- 👤 D Fried
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 23:04
CPC Classifications
B; B66; B66B; B66B5/00; B66B5/02; B66B5/021; B66B5/024
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
181 words
In an elevator system for use in a multi-level building including at least one elevator car vertically movable in a shaftway between the levels, said car having a door, and means for opening said door when said car comes to rest at the levels, temperature sensing means mounted on said car door, means for producing an electrical signal that varies in accordance with the temperature sensed by said sensing means, and control means including means coupled to said sensing means for disabling said car door opening means when the temperature sensed by said sensing means exceeds a predetermined value, said control meanS further comprising threshold means for producing a first signal when said electric signal is below a reference level, and a second signal when said electric signal is greater than said reference level, and switch means coupled to said door opening means, said switch means being placed into a first condition in response to said first signal to enable said door opening means and into a second condition in response to said second signal to disable said door opening means.
Claim 2
Dependent Claim
181 words
In an elevator system for use in a multi-level building including at least one elevator car vertically movable in a shaftway between the levels, said car having a door, and means for opening said door when said car comes to rest at the levels, temperature sensing means mounted on said car door, means for producing an electrical signal that varies in accordance with the temperature sensed by said sensing means, and control means including means coupled to said sensing means for disabling said car door opening means when the temperature sensed by said sensing means exceeds a predetermined value, said control meanS further comprising threshold means for producing a first signal when said electric signal is below a reference level, and a second signal when said electric signal is greater than said reference level, and switch means coupled to said door opening means, said switch means being placed into a first condition in response to said first signal to enable said door opening means and into a second condition in response to said second signal to disable said door opening means.
Claim 3
Dependent Claim
59 words
The system of claim 1, in which said sensing means comprises first and second sensors respectively mounted on the upper and lower walls of the car walls, and means interposed between said sensors and said threshold means for coupling the output of one of said sensors to said threshold means depending on the direction of travel of said car.
Claim 4
Dependent Claim
28 words
The system of claim 2, further comprising means for periodically establishing said reference level each time said car is moved away from rest at one of said landings.
Claim 5
Dependent Claim
61 words
The system of claim 3, in which said reference signal establishing means comprises signal storing means having an output coupled to said threshold means, and means interposed between said sensing means and said signal storing means and responsive to the acceleration of the car away from a landing to temporarily couple the output of said sensing means to said storing means.
Claim 6
Dependent Claim
69 words
The system of claim 4, in which said switch means comprises a first relay energized only when said threshold means produces one of said first and second signals, and a second relay energized in response to the change of state of energization of said first relay, the contacts of said second relay being normally closed and connected in series with a voltage source and said car door opening means.
Claim 7
Dependent Claim
29 words
The system of claim 5, further including a fireman''s return circuit, said improvement further comprising means for enabling the fireman''s return circuit upon the operation of said disabling means.
Claim 8
Dependent Claim
71 words
The system of claim 6, including a plurality of elevator cars each comprising temperature sensing means, door opening means, and means for disabling said door opening means upon the detection at the corresponding one of said sensing means of a temperature exceeding a predetermined value, said fireman''s return enabling means being operated in response to the detection of a temperature exceeding said predetermined value at at least two of said cars.
Claim 9
Dependent Claim
26 words
The system of claim 6, further comprising means coupled to said disabling means for indicating at which level a temperature exceeding said predetermined value is detected.
Claim 10
Dependent Claim
44 words
The system of claim 2, in which said sensing means comprises an optical pyrometer mounted one one of the upper and lower walls of said elevator car and having a sensing axis extending substantially normal to the direction of movement of said elevator car.
Claim 11
Dependent Claim
28 words
The system of claim 1, further comprising means for periodically establishing said reference level each time said car is moved away from rest at one of said landings.
Claim 12
Dependent Claim
69 words
The system of claim 1, in which said switch means comprises a first relay energized only when said threshold means produces one of said first and second signals, and a second relay energized in response to the change of state of energization of said first relay, the contacts of said second relay being normally closed and connected in series with a voltage source and said car door opening means.
Claim 13
Dependent Claim
29 words
The system of claim 1, further including a fireman''s return circuit, said improvement further comprising means for enabling the fireman''s return circuit upon the operation of said disabling means.
Claim 14
Dependent Claim
71 words
The system of claim 12, including a plurality of elevator cars each comprising temperature sensing means, door opening means, and means for disabling said door opening means upon the detection at the corresponding one of said sensing means of a temperature exceeding a predetermined value, said fireman''s return enabling means being operated in response to the detection of a temperature exceeding said predetermined value at at least two of said cars.
Claim 15
Dependent Claim
26 words
The system of claim 1, further comprising means coupled to said disabling means for indicating at which level a temperature exceeding said predetermined value is detected.
Claim 16
Dependent Claim
44 words
The system of claim 1, in which said sensing means comprises an optical pyrometer mounted on one of the upper and lower walls of said elevator car and having a sensing axis extending substantially normal to the direction of movement of said elevator car.
References Cited (Backward Citations)
US3726364A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-28 | 1977-07-30 | 1978-01-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-28 | 1981-07-30 | 1982-01-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-28 | 1985-07-30 | 1986-01-29 | $7700.00 | Window Closed / Lapsed |