US3726364A

US3726364A - Elevator heat controlled safety circuit

Info

Publication number: US3726364A
Application number: US00117561A
Authority: US
Inventors: Y Citrin; T Imperatore
Original assignee: THERMOCYCLE Inc
Current assignee: THERMOCYCLE Inc
Priority date: 1971-02-22
Filing date: 1971-02-22
Publication date: 1973-04-10
Anticipated expiration: 1990-04-10

Abstract

A safety circuit for preventing the operation of the hall call and car call circuitry in an automatic elevator control system whenever the temperature sensed at a hall call button at any landing exceeds a predetermined value. A temperature controlled switch is positioned in the hall call button enclosure and operates when the predetermined temperature level is sensed to effectively disable the hall and car call relay circuitry for any landing at which an excessive temperature is sensed so as to prevent an elevator car from stopping at that landing.

Description

United States Patent [191 Citrin et al.

I54] ELEVATOR HEAT CONTROLLED SAFETY CIRCUIT [75] Inventors: Yale Citrin, Scarsdale; Thomas Imperatore, Long Island, both of NY.

[73] Assignee: Thermocycle, Inc., Brooklyn, NY.

[22] Filed: Feb. 22, 1971 [21] Appl. No.: 117,561

Z? SENSOR 5 SWITCHi 24V FFN Z0 74" LANDING TERMINA L LANDING BUTTON BOX 4 [4 1. Apr. 10, 1973 3,236,332 2/1966 Burgy et al. ..l87/29 3,482,146 12/1969 McMorrow et a1 ..318/473 X Primary Examiner--Bernard A. Gilheany Assistant Examiner-W. E. Duncanson, Jr. Att0rneySandoe, Hopgood and Calimafde ABSTRACT A safety circuit for preventing the operation of the hall call and car call circuitry in an automatic elevator control system whenever the temperature sensed at a hall call button at any landing exceeds a predetermined value. A temperature controlled switch is positioned in the hall call button enclosure and operates when the predetermined temperature level is sensed to effectively disable the hall and car call relay circuitry for any landing at which an excessive temperature is sensed so as to prevent an elevator car from stopping at that landing.

4 Claims, 2 Drawing Figures 70 UP HALL SELECTOR CONTACT ro muse SUPPLY T0 DOWN MALL SELECTOR CONTACT FF! 1% were? sewson sowrcu ELEVATOR HEAT CONTROLLED. SAFETY CIRCUIT The present invention relates generally to elevators, and more specifically to a temperature-sensitive safety circuit for use in an automatic elevator control system.

The majority of office buildings and residential apartment houses are provided with automatic elevator control systems in which the elevator cars are moved between floors on landings in the building in response to car and hall calls made by actual and prospective passengers.

A hall call is commonly made at a floor or landing by the operation of a button at a panel located at each landing near the elevator door. Conventionally, two buttons are provided at each floor intermediate the upper and lower floors; one for operation when the passenger desires to be conveyed to a higher floor, and the other to be operated when the passenger wishes to be taken to a lower floor.

A car call is made by the operation of a selected floor button on a floor select button panel located within each elevator car. Normally each car select panel contains one button for each floor in the building, although in many installations in which the elevator cars only service floors at different zones, the select panel in each car contains only buttons for'those floors in the zone serviced by that car.

A recent, widely utilized development in automatic elevator control systems is the use of glow discharge tubes or Touch Buttons for operation by the passenger in the making of hall and/or car calls. In the operation of these switches or buttons, the capacitance of the passengers fingerv when placed on the button causes the tube to discharge and to produce a glow which provides a characteristic visual indication of the operation of that button. The discharge of the tube also I completes and energizes a relay circuit to operate an associated group of relays to register the call and discharge an elevator car to the desired floor, all in a manner that is well known in the art and thus requires no further description herein.

It has, however, been discovered that touch button switches are also sensitive to temperature; that is, for reasons that are not yet completely understood, the touch button tube may also discharge in response to the presence of .heat even if it is not operated -by a passenger. THis has created a significant potential for tragedy such as that resulting from the outbreak of a fire at a floor which in turn actuates the hall call button at that floor.

The resulting undesired operation of the hall call discharge switch in turn will cause an elevator car to be discharged from a floor at which there is no fire to the floor affected by the fire. Once the car arrives at the latter floor, the car will thereafter be prevented from leaving there since the hall call switch remains in the actuated condition even after the car arrives, unlike a normal response to a hall call in which the hall call registration is cancelled upon the arrival of the car at the floor. As a result, passengers in the elevator car may become trapped at the floor and may succomb to the effects of the tire, particularly if the elevator car door buckles as a result of the heat so that it cannot thereafter'be operated. Moreover, passengers attempting to flee from the fire by the use of the elevator are prevented from doing so since the elevator car cannot be removed from the floor as long as the hall call touch button at the floor remains actuated as described above.

Another potential tragedy in the event of a tire at any floor may result when a car call is made to that floor by a passenger in the car who is unaware of the existence of the tire. That car call would ordinarily cause the elevator car to be conveyed to the floor from which it could not thereafter be moved for reasons noted previously with similar potentially tragic results.

It is an object of the invention to provide an elevator safety system for preventing an elevator car from responding to a hall call or car call to a floor at which the temperature exceed a redetermined value as a result of a tire at that floor.

It is a further object of the invention to provide in an automatic elevator system a temperature-responsive safety system which requires a relatively minor modification to the elevator system by the addition of relatively inexpensive and compact, yet reliable components.

It is a general object of the invention to provide a modification to an otherwise conventional automatic elevator control system in which the likelihood of tragedy as a result of a tire in the building is significantly reduced.

It is another object of the invention to provide an automatic elevator control system of the type described in which normal operation is automatically resumed when the cause of excessive temperature, such as a fire at a landing, is removed.

Broadly considered, the present invention provides, in an otherwise conventional automatic elevator control system, a temperature sensing device, which, when the ambient temperature reaches a predetermined value, operates a switch. The operation of that switch in turn is effective to prevent the actuation of the hall call relay circuitry associated with the floor at which the excessive temperature is sensed, even if the ambient temperature causes the actuation of the hall call switch at that floor, as may occur. In addition, the operation of the temperatureresponsive switch prevents the registration of car calls unwittingly made to the affected floor which would in the absence of the circuit of the invention cause the car to stop at that floor.

The safety system of the invention thus prevents an elevator car from being called to and then trapped at a floor at which a fire has broken out, and, in addition, permits the elevator car to be employed to safely remove people from that floor even if the increased temperature caused by the fire causes a subsequent undesired actuation of the hall call switch. Upon the resumption of normal temperature at the landing switch box, such as when the fire is extinguished, the temperature sensor is returned to its normal condition and normal operation of the elevator in responding to both hall and car calls is resumed.

To the accomplishment of the above and to such further objects as may hereinafter appear, the present invention relates to an elevator heat controlled safety circuit, substantially as defined in the appended claims and as described in the following specification taken together with the accompanying drawing in which:

FIG 1 is a schematic diagram of an intermediate and terminal landing hall call button circuit as modified in otherwise conventional elevator automatic control system which in the event of a fire at a floor or landing in thebuilding servicedby the system, disables the hall and car call circuits for that landing, to thereby prevent the occurrence of a tragedy resulting from an elevator car containing passengers being transported to and then trapped in the elevator car at that landing. As herein described, the circuit of the invention is employed in combination with glow-discharge tube or touch button switches in which conduction and thus the registration of hall and car callsare made in response to the increased capacitance established between the tube electrodes as a result of the placement of a finger in proximity to the tube. It has been found that this type of call registration switch is likely to be actuated by excessive ambient temperature even when not pressed by an individual passenger.

The safety circuit of the invention thus has particular utility in an elevator automatic control system utilizing glow discharge tube switches, but it will be appreciated that the invention also has utility in automatic elevator control systems employing other types of switches for making hall and/or car calls.

As shown in FIG. 1, a hall call panel or box such as 10 is located at each intermediate landing or floor N in the building so that a would-be passenger may operate either an UP button or a DOWN button dependingon the passengers intended direction of travel from the landing in the building to which the car may be directed in response to a car call. Thus, as shown in FIG. 2, panel 24 contains

discharge tubes

26, 28, 30 and 32 for making hall calls to the first, second, third and fourth floors respectively, it being understood that additional touch buttons or discharge tubes are provided in the panel for each additional floor in the building serviced by the elevator car in which the particular panel is housed.

As in the hall call discharge tube circuit of FIG. 1, the anode of each discharge tube is connected to a suitable power supply through a resistor R3, and the grid of each tube is coupled to the cathode of the tube through a capacitor C2 at a junction point 34, the latter also being coupled to a supply voltage through a resistor R4. The grid of each discharge tube is also coupled to a second voltage supply line through a resistor R5 such that the resulting bias voltage on the grid is sufficient to keep the tube in the non-conducting state.

The cathode of each tube is respectively coupled through the normally closed contacts of the floor fire relays, here shown as contacts FFIC, FF2C, FF3C and FF4C respectively operating in response to the FF relays for the first'through the fourth floor in the building to the remotely-located car call selector panel (not shown) at which car calls are registered in response to the making ofa car call.

In normal hall call operation a would-be passenger operates either the UP or DOWN button at the floor at which he is located to cause an elevator car to be discharged to that floor. The operation of the button introduces an additional capacitance between the anode landing. Those buttons are here shown in the form of

glow discharge tubes

12 and 14 which are actuated respectively in a manner to be described below for an UP or a DOWN hallcall.

Ata terminal landing such as the-lobby or an office building, a hall button terminal 10a contains only a sin-. gle switch, here also shown as a touch button or glow discharge tube 16. The plate of each glow tube is connected to a remotely located power supply through a resistor R1, and the shield of each tube is connected to the power supply through a resistor R2. The control grid of each hall call glow discharge tube is connected to a source of a biasing voltage through a resistor R3 to normally maintain the tubes in a non-conducting state; that is, a state in which conduction between the anode and cathode of the tubes is prevented. The cathode of each tube is connected to the grid of that tube by a capacitorCl.

In accordance with the present invention, a temperature-sensitive sensor and switch l8 is placed in each hall panel 10, and is connected in series with a power supply at 20 and the coil 22 of a floor. fire (FF) relay. In

or cathode of the tube and ground causing that tube to tire or discharge in a known manner. The resulting firing of the tube causes current to flow to the associated hall call relay to in turn register the thus made hall call and cause a car to be discharged in response to the hall call. The firing of the tube also causes the tube to glow so as to provide a visual indication to the passenger that his hallcall is being processed.

A, car call is made in substantially the same manner by pressing the proper floor button located in the car selector panel, to thereby cause the associated tube in that panel to discharge and glow and to cause an associated relay to be energized for registering the car call, thereby causing that car to be conveyed to the selected floor.

In accord with the safety circuit of the present invention, whenever the ambient temperature at the hall call box 10 at one or more floors exceeds a predetermined temperature, e.g., F, the sensor 18 located in the hall call box at that floor is actuated causing the sensor controlled switch to close, thereby energizing the FF relay associated with that floor. For example, when the affected floor; that is a floor at which a fire has caused the actuation of a sensor 18. Stated differently, the energization of the floor fire relay for the affected floor and the resulting opening of the associated hall call and car call contacts prevent the registration of both hall and car-calls to that floor even though the excessive heat at the hall call box at the floor may cause the hall call discharge tubes to conduct. Moreover, if an elevator car is already at the affected floor, it will be permitted to be moved therefrom by a car call made from the car even if the hall call button remains energized as a result of the excessive heat.

The safety circuit of the invention thus effectively and reliably isolates the affected floor from elevator service. As a result, elevator car passengers not knowing of the fire are prevented from unwittingly being taken to the affected floor where they might become trapped. In addition, the elevator car is reliably prevented from being dispatched to the affected floor in response to a fire-actuated hall call, and also permits a car already at the floor to leave the affected floor.

The components required to modify the otherwise conventional elevator system to produce the temperature-sensitive safety circuit are relatively few in number and are inexpensive, but yet reliable as required in a safety system. When the hall temperature returns to a normal level, such as when the hall fire is extinguished, the sensor-switch located in the hall call button box automatically returns to its normal open condition, causing the FF relay to be de-energized and its contacts to return to their normally'closed condition. At this time, normal, operation of the elevator system resumes and both car and hall calls can be made to the previously affected floor.

A temperature sensor switch which may be, used to advantage in the safety circuit of the invention is one can also beused with hall and car call switches other than the touch tubes herein specifically disclosed.

It is also considered within the scope of the invention to couple the temperature-sensor switch 18 to alarm circuitry located at a convenient area in the building to provide a quick indication of the fire in addition to disabling the elevator control circuit as described hereinabove.

Thus, while the invention has been herein described with respect to a single embodiment, it will be understood that modifications may be made therein without departing from the spirit and scope of the invention.

We claim:

1. In an automatic elevator control system including a first plurality of switching means located respectively at each landing of a multi-landing building for making hall calls, a second plurality of switching means located in the interior of an elevator car for making car calls, and registration and control means coupled to said first and second plurality of switching means for respectively conveying the car to a landing at which a hall call is made or in response to a car call; the improvement which comprises: fire sensing means located at selected landings, a third and fourth plurality of switch means in respective operative circuit relation with said first and second switching means and effective when actuated to respectively disconnect selected ones of said first and second plurality of switching means from said registration and control means, and a plurality of fifth switching means respectively coupled to said firesensing means and actuated thereby when said fire sensing means detects the presence of a fire at one of said landings said fifth switching means being effective when thus actuated to actuate corresponding ones of said third and fourth pluralities of switching means and thereby disconnect corresponding ones of said first and second pluralities of switching means from said control means as long as said fire is sensed at said one of said landings.

2. The improvement of claim 1, further comprising a plurality of relays respectively coupled to each of said fifth plurality of switching means and energized in response to the actuation of corresponding ones of said fifth plurality of switching means, said fourth plurality of switching means including a plurality of contacts respectively actuated in response to the energization of corresponding ones of said relays.

3. The improvement of claim 2, in which said first plurality of switching means each include glow discharge tubes located in enclosures respectively mounted at each landing, said fire sensing means including temperature sensing means, said temperature sensing means and said fifth switching means each being respectively mounted within said enclosures in proximity to said glow tubes.

4. In an automatic elevator control system including at least one elevator car for service at a plurality of landings in a building, a first plurality of switch means, each including a glow discharge tube respectively located at each of said landings for making hall calls for elevator service to a corresponding one of said landings, a second plurality of switch means located in said car for making car calls to selected ones of said landings, means coupled to said first and second plurality of switch means for registering the operation of one of said first and second plurality of switch means for controlling the movement of said car to one of said landings in response to a car call of a hall call made for one of said landings, and a plurality of fire sensitive switching means including temperature-sensitive means respectively located at each of said landings in respective proximity to said glow discharge tubes and actuated upon the sensing thereby of a fire at said landing, registering effective when thus actuated to unconditionally disable said regiserting means, to thereby prevent car service to the one of said landings at which a fire is sensed.

l t t

Claims

1. In an automatic elevator control system including a first plurality of switching means located respectively at each landing of a multi-landing building for making hall calls, a second plurality of switching means located in the interior of an elevator car for making car calls, and registration and control means coupled to said first and second plurality of switching means for respectively conveying the car to a landing at which a hall call is made or in response to a car call; the improvement which comprises: fire sensing means located at selected landings, a third and fourth plurality of switch means in respective operative circuit relation with said first and second switching means and effective when actuated to respectively disconnect selected ones of said first and second plurality of switching means from said registration and control means, and a plurality of fifth switching means respectively coupled to said firesensing means and actuated thereby when said fire sensing means detects the presence of a fire at one of said landings said fifth switching means being effective when thus actuated to actuate corresponding ones of said third and fourth pluralities of switching means and thereby disconnect corresponding ones of said first and second pluralities of switching means from said control means as long as said fire is sensed at said one of said landings. 2. The improvement of claim 1, further comprising a plurality of relays respectively coupled to each of said fifth plurality of switching means and energized in response to the actuation of corresponding ones of said fifth plurality of switching means, said fourth plurality of switching means including a plurality of contacts respectively actuated in response to the energization of corresponding ones of said relays.