US3872949A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overspeed prevention system for elevator cars
Assignee: Doosan Bobcat North America Inc
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Filing: 1970-06-15
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Granted: 1975-03-25
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Expires: 1990-06-15
Abstract
Abstract An overspeed prevention system for elevator cars is disclosed which is especially adapted for elevators of the type used in material handling systems. Speed responsive means in the form of an electrical generator is provided on the elevator car and produces an output voltage of one polarity exceeding a predetermined magnitude in response to overspeed in the upward direction and produces an output voltage of the opposite polarity and exceeding a predetermined magnitude in response to overspeed in the downward direction. A first polarity responsive switching means is effective to de-energize the elevator motor in a regulated manner in response to upward overspeed. A second polarity responsive switching means responds to the downward overspeed voltage and initiates the application of brake means to stop the elevator car. The brake means includes a pair of brakes which utilize an actuator including one or more pair of brakes which utilize an actuator including one or more pyrotechnic charges which are provided with electrical detonators. The switching means are effective to connect the generator to the detonator circuit for the pyrotechnic charges and, to ensure firing thereof, pulsing means are interposed to provide repetitive firing impulses across the detonator circuit.
Inventors
- 👤 James H Snyder
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:48
CPC Classifications
B; B66; B66B; B66B5/00; B66B5/02; B66B5/16; B66B5/18; B66B5/20; B66B5/04; B66B5/06
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
84 words
An overspeed brake control system for an elevator comprising: an electrical generator adapted to be operatively connected With an elevator car to generate a voltage corresponding to the speed of the car, brake means for said car including a pyrotechnic actuator therefor with an electrical detonator, and voltage responsive switching means connected with the generator and adapted to connect said generator with said electrical detonator when the voltage of the generator reaches a predetermined value upon the occurrence of excessive speed of said car.
Claim 2
Dependent Claim
84 words
An overspeed brake control system for an elevator comprising: an electrical generator adapted to be operatively connected With an elevator car to generate a voltage corresponding to the speed of the car, brake means for said car including a pyrotechnic actuator therefor with an electrical detonator, and voltage responsive switching means connected with the generator and adapted to connect said generator with said electrical detonator when the voltage of the generator reaches a predetermined value upon the occurrence of excessive speed of said car.
Claim 3
Dependent Claim
49 words
The invention as defined in claim 1 wherein said generator is a direct current generator and said voltage responsive switching means is connected thereto through a unidirectionally conductive device so that said switching means is responsive only to the generator voltage corresponding to downward motion of the elevator car.
Claim 4
Dependent Claim
32 words
The invention as defined in claim 2 wherein said voltage responsive switching means comprises a voltage sensitive relay including an energizing coil and switching contacts connected in parallel therewith to said detonator.
Claim 5
Dependent Claim
102 words
The invention as defined in claim 3 including a transformer having a primary winding connectable across said generator through said switching contacts and a secondary winding connected across said electrical detonator, the transformer primary being connected across the generator when said switching contacts are closed to produce a first voltage impulse across said detonator, the core of said transformer being driven into magnetic saturation by the generator current thereby producing a voltage across said relay below said predetermined value whereby the switching contacts open and interrupt the primary current in said transformer and thereby produce a second voltage impulse across the detonator.
Claim 6
Dependent Claim
35 words
The invention as defined in claim 1 including a pulse producing means connected between said generator and said detonator whereby repeated pulses are applied to the detonator while the speed of the car is excessive.
Claim 7
Dependent Claim
46 words
The invention as defined in claim 5 wherein the pulse producing means includes said switching means and reactive impedance adapted to impose a time varying load on said generator so that the voltage thereof varies above and below said predetermined value when the speed is excessive.
Claim 8
Dependent Claim
56 words
The invention as defined in claim 5 wherein said pyrotechnic actuator includes plural pyrotechnic charges each having an electrical detonator, all of said detonators being connected in parallel to said pulse producing means whereby the detonators are subjected to repeated voltage pulses to insure that each pyrotechnic charge is fired in response to an overspeed condition.
Claim 9
Dependent Claim
51 words
The invention as defined in claim 7 wherein said brake means is provided with electrical switching means operatively connected with said actuator and electrically connected with the drive means for said elevator car and being adaptd to interrupt said drive means when said brake means is actuated by the pyrotechnic actuator.
Claim 10
Dependent Claim
44 words
The invention as defined in claim 1 wherein said brake means comprises a brake shoe and operating member connected with said actuator and engageable with said brake shoe for displacing the same to cause energization of said brake means to stop said elevator car.
Claim 11
Dependent Claim
147 words
An overspeed prevention system for an elevator comprising: an elevator car movable relative to a frame by a drive motor and comprising a direct current electrical generator operatively connected between the car and the frame and adapted to generate a voltage corresponding to the speed of the elevator car, brake means for said car including an electrically energized actuator therefor, a first unidirectionally conductive voltage responsive switching means connected with the generator and responsive to a predetermined voltage of one polarity for connecting said generator across said electrical energizing means to cause said brake means to be actuated when said elevator car is moving downwardly at an excess speed and second unidirectionally conductive voltage responsive switching means connected with said generator and responsive to a predetermIned voltage of the other polarity for de-energizing said drive motor when said elevator car is moving upwardly at an excessive speed.
Claim 12
Dependent Claim
147 words
An overspeed prevention system for an elevator comprising: an elevator car movable relative to a frame by a drive motor and comprising a direct current electrical generator operatively connected between the car and the frame and adapted to generate a voltage corresponding to the speed of the elevator car, brake means for said car including an electrically energized actuator therefor, a first unidirectionally conductive voltage responsive switching means connected with the generator and responsive to a predetermined voltage of one polarity for connecting said generator across said electrical energizing means to cause said brake means to be actuated when said elevator car is moving downwardly at an excess speed and second unidirectionally conductive voltage responsive switching means connected with said generator and responsive to a predetermIned voltage of the other polarity for de-energizing said drive motor when said elevator car is moving upwardly at an excessive speed.
Claim 13
Dependent Claim
18 words
The invention as defined in claim 10 wherein said actuator includes a pyrotechnic charge with an electrical detonator.
Claim 14
Dependent Claim
158 words
An overspeed prevention system for an elevator car movable relative to a frame by a driving motor and comprising a direct current generator operatively connected between the elevator car and the frame and adapted to generate a voltage corresponding to the speed of the car, brake means for said car including at least one brake shoe, a pyrotechnic actuator therefor with an electrical detonator, switching means for de-energizing said driving motor, first unidirectionally conductive voltage responsive means connected with said generator and adapted to connect said generator across said electrical detonator when the voltage of the generator reaches a predetermined value and is of a polarity corresponding to downward motion of said car, and second unidirectionally conductive voltage responsive means connected with said generator and adapted to actuate said switching means for de-energizing said driving motor when the voltage of said generator reaches a predetermined value and is of a polarity corresponding to upward motion of said car.
Claim 15
Dependent Claim
158 words
An overspeed prevention system for an elevator car movable relative to a frame by a driving motor and comprising a direct current generator operatively connected between the elevator car and the frame and adapted to generate a voltage corresponding to the speed of the car, brake means for said car including at least one brake shoe, a pyrotechnic actuator therefor with an electrical detonator, switching means for de-energizing said driving motor, first unidirectionally conductive voltage responsive means connected with said generator and adapted to connect said generator across said electrical detonator when the voltage of the generator reaches a predetermined value and is of a polarity corresponding to downward motion of said car, and second unidirectionally conductive voltage responsive means connected with said generator and adapted to actuate said switching means for de-energizing said driving motor when the voltage of said generator reaches a predetermined value and is of a polarity corresponding to upward motion of said car.
Claim 16
Dependent Claim
90 words
An overspeed brake control system for an elevator comprising: an elevator car movable relative to a frame, brake means for said car including a pyrotechnic actuator therefor with an electrical detonator, a source of voltage on said car, control means responsive to the speed of said elevator car for connecting the voltage source to the electrical detonator, said brake means comprising at least one brake shoe, and an operating member connected with the actuator and engageable with the brake shoe for displacing it into engagement with the brake reaction member.
Claim 17
Dependent Claim
90 words
An overspeed brake control system for an elevator comprising: an elevator car movable relative to a frame, brake means for said car including a pyrotechnic actuator therefor with an electrical detonator, a source of voltage on said car, control means responsive to the speed of said elevator car for connecting the voltage source to the electrical detonator, said brake means comprising at least one brake shoe, and an operating member connected with the actuator and engageable with the brake shoe for displacing it into engagement with the brake reaction member.
Claim 18
Dependent Claim
25 words
The invention as defined in claim 13 wherein said voltage source is a direct current generator operatively connected between the elevator car and the frame.
Claim 19
Dependent Claim
41 words
The invention as defined in claim 14 wherein said control means is a voltage responsive switching means connected with the generator and adapted to connect the generator to the electrical detonator when the voltage of the generator reaches a predetermined value.
Claim 20
Dependent Claim
19 words
The invention as defined in claim 15 including a pulse producing means connected between the generator and the detonator.
Claim 21
Dependent Claim
66 words
The invention as defined in claim 16 wherein said brake means includes first and second brakes, each including an actuator with plural pyrotechnic charges, each of said charges having an electrical detonator, said detonators being connected in parallel to said pulse producing means whereby the detonators are subjected to repeated voltage pulses to insure that each pyrotechnic charge is fired in response to an overspeed condition.
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) | 1978-03-24 | 1978-09-23 | 1979-03-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-03-24 | 1982-09-23 | 1983-03-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-03-24 | 1986-09-23 | 1987-03-25 | $7700.00 | Window Closed / Lapsed |