CA1105160A - Elevator system door tampering protection circuits - Google Patents

Abstract

ELEVATOR SYSTEM DOOR TAMPERING
PROTECTION CIRCUITS

ABSTRACT OF THE DISCLOSURE: An automatic elevator system having car movement controls, door controls, a door operating mechanism for automatically opening and closing at least the car door and first switch contacts operable when the car and hoistway doors are closed to permit the car to move from a floor in combination with further switch contacts which are operable in accordance with the positions of the doors and which prevent the car from moving from a floor when the first switch contacts are operated before the further switch con-tacts to prevent movement of the car from a floor when the first switch contacts have been operated or shunted by un-authorized persons or by a short circuit.

Description

This invention relates to circuits Eor preventing elevatox car movement from a floor in the event that normal operation of conventional door swit:ches and/or interlock switches used therewith has been modified by interference therewith or shorting thereof.
Automatic elevator car syst:ems, i.e., systems in which the car door automatically opens when the car reaches a 100r and close before the car leaves a floor, are well-known in the ar~. In such systems, the hoistway door may be automatically opened and closed or may be manually opened and closed. In such systems, there usually is a switch or switches operable when the hoistway door is closed and a switch or switches operable when the car door or gate is closed which permits the car hoisting apparatus to move the car to another floor when all switches have heen operated.
Also, such systems usually include locking circuits which pre-vent opening of the doors unless the car is substantially level with the floor at which the doors control entrance to and egress from the car and include a safety edge on one or more of the doors to recycle the doors and prevent starting of a car from a floor when closing of a door is obstructed.
Such known systems operate satisfactorily when there is no deliberate interference therewith. However~
juveniles, persons intending to commit robbery and others, find it exciting or convenient to interfere with the normal operation for mischievous or criminal reasons and learn how to disable a car, to prevent normal door operation or to leave open a hoistway door after the car has left the floor where the door is located.
For example, when the hoistway door is open, the switch or switches operab~e thereby are accessible to the knowledgeable. Although s~lch opening of the door will, by reason of the co~ventional circuits, stop the associated car, the hoistway door switch, which is on the hoistway wall, may be disabled or ~-passed intentionally, such as by a shunt, to permit the car to continue to opel-ate or may be accidentally by-passed, such as by shorting thereof.
Similarly, the car door or gate switch or switches are accessible from the car doorway or the hoistway doorway, and if the switch or switches are disabled or by-passed, the car will move even if the door or doors of the car are not closed, creating a passenger hazard and permitting the car to be stopped and started by manipulation of the car door switch or switches.
Conventional elevator systems also may have eit:her an automatic sliding or a manually operable, swinging hoist-way door.
Many of such known systems are in use, and the main object of the invention is to permit the addition to such systems of relatively simple apparatus which will make it ex-tremely difficult to tamper with normal operation of an ele-vator car without causing the car to remain at the floor where the tampering occurs and, preferably, causing the sounding of an alarm. However, the principles of the invention are also applicable to newly 1nstalled elevator systems.
It has heretoore been proposed for elevator systems ha~ing swinging hoistway doors that duplicate hoistway or floor door switches be added at the ~loors of a building which are inaccessible from the car or hoistway doorway and which are .
protected to prevent movement of a car~when the normal floor door switches are tampered with or are accidentalIy by-passed.

~ However, such duplicate switches must be installed in the , ~

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. - . , . . . . -- . .. . ~' hoistway with separate wiring and protect against only by-passing of the floor door operated switches. Also, such duplicate, or back-up, swltches are operated at the same time as the normal switches and lf similar switches are used in elevator systems having power operated, sliding, hoistway doors, the car would be stopped at a floor with the doors closed thereby preventing passeng~er egress without further action by a passenger or supervisory personnel. In the pre-ferred embodiment o the invention for the latter elevator system, the doors are prevented from closing and are re-opened if partly closed when the normal floor door switches or the normal car door switches are by-passed or tampered with.
In the preferred embodiment of the in~ention for use when both the hoistway and car doors are of Lhe sliding type, two switches are provided at the top of the elevator car where they are inaccessible except by gaining access to the top of the car, and such access to the top of the car can be gained substantially only by authorized personnel or those with the special knowledge of such personnel. Such switches are operable by a cam or cams driven by the car door opera-ting mechanism on the top of the car and control relays which interrupt the circuits for the car hoisting apparatus, which ; cause the doors to open and which, preferably, cause an alarm to sound whenever the hoistway door or the car door is not almost ully clo~;ed when the switches normally operated by such doors to inclicate that the car should start have been operated or by-passed beore the doox reaches ~he almost ully closed position t:hereof. In such almost fully closed positions, such normally operated switches are inaccessible from the Eloor or Erom inside the car. Preferably, also, the hoistway ~;
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door or doors and the car doors are provided with mechanical interengaging devices so that, when a car is at a floor, the hoistway door at the floor cannot ~e opened without opening the car door and the ca.r door cannot be closed without closing the hoistway door at the -Eloor.
In the preferred embodiment of the invention for use when the hois~way door is a swinging door and the car door or doors are of the sliding type, three switches, one actuated by the hoistway door and located at an inaccessible position, such as above the door frame and enclosed, and the other two at an inaccessible position on top of the car and operable by a cam or cams driven by the car door operating mechanism, are used to control relays which interrupt circuits for the car hoisting apparatus, which cause -the car doors to remain open or re-open and which, preferably, cause an alarm to sound whenever the switch normally operable by the hoistway door is operated or by-passed before the hoistway door reaches its almost fully closed position, whenever the switch nor~ally operable by the car door is operated or by-passed be~or~ the car door is substantially fully closed, and whenever the door interlock switches are operated or by-passed before the car door is substantially fully closed~ .
One advantage of the invention is that protec'cion against tampering with the normal operation of the elevE~or system is provided~with relatively simple changes in a con-ventional automatic elevator system.
Another ad~antage of the embodiment of the in-vention is: that in elevator systems in which both the hoist-way and car doors are of the sliding type, it is unnecessary to add equipment on the hoistway wall and.the doors re-open if the hoistway door or car door switches are tampered with.

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According to a broad aspect of the present invention, there is provided in an automatic elevator system having an elevator car with a car : door, means mounting said car in a hoistway extellding between a plurality of floors in a building, a floor door at each of said floors for providing access to said car, control means including hoisting apparatus for moving said car from one of said floors to another and stopping said car at a floor, door operating means for automatically opening and closing at least said car door when the car is at a floor and switch means operable in accordance with the positions of said car door and each said floor door for controlling said control means and permitting said control means to move said car f.rom said floor to another when said car door and each said floor door is closed, the combination therewith of further switch means operable in accordance with the position of at least one of said car door and said floor door and normally operable prior to the operation of at least part of said first-mentioned switch means, and means connecting said further switch means in circuit with said control means for preventing movement of said car when said part of said first-mentioned switch means is operated prior to operation of said further switch means.

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Other objects and advantages of the invention will be apparent to those skilled in the art from the -following description of the presently preferred embodiments khereof, which description should be considered in conjunction with the accompanying drawings in which:
Fig. 1 is a schematic diagram of -the preferred embodiment of the invention or use in connection with elevator systems having both an automatically driven car door and an automatically driven hoistway or floor door;
Fig. 2 is a diagrammatic, fragmentary, top view of a one-part, sliding hoistway door and a one-part, sliding car door;
Fig. 3 is a diagrammatic, fragmentary, top view of a two-part sliding hoistway door and a two-part sliding car door;
Fig. 4 is a schematic diagram of the preferred embodiment of the invention for use in connection with an elevator system having an automatically driven car ~0 door and a manually operable swinging hoistway door;
and Pig. 5 is a diagrammatic, fragmentary, top view o~ a swinging hoistway door in conjunction with the switch operated thereby and shown in Fig. 3.

Conventional Sliding Door System and Modification As mentioned hereinbefore, the invention relates to modification oi well-known types of automatic elevator car ~-systems. Such systems and components thereof are, for ex-3~0 ample, lllustratedl in United States Patents Nos: 1,680,771;

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1,876,438; 1,929,391, 2,019,456; 2,185,7~8 and 2,432,293 and in various technical publications including service manuals published by various elevator manufacturers.

In general terms, such systems include the following:
(1) At least one elevator car mounted for vertical movement in a hoistway extending between a plurality of floors in a building, said car having a sliding door, either one, two or more parts.

(2) A hoistway door at each of the floors to provide access to the car, the door usually being of one or more sliding parts or being a one~part, pivotally mounted, swlnglng door.
(3~ Control means including hoisting apparatus for moving the car from one of the 100rs to another, stopping the car at a floor, causing opening and closing at least of the car door a~ a floor at which the car is stopped, such control means being respon~bl-~ to manually operable push buttons in the car and at each floor, to various switches on the car and at the floors, ~tc.
t4) Motor driven door operating means at the top of the car for opening and closing the car door when the floor door is a swinging door and both the car door and the floor door when both doors are sliding doors.
(S) A plurality of switches on the car and at the floors which are connected to the control means and which, ~::
: when all the doors are closed and:locked, permit opera-: tion of the circuits in the control means which:cause : the car to move.:Usua1ly included in such plurality of switches are a switoh at each:floor controlled in ac-cordance with l:he posltion of the car~door and operated :
' ' ~ '........ , . , ~
'. ' : ' ': ' -by the locking mechanisms which hold the doors closed until the locking mechanisms are automatically released when the car is at a Eloor.
(6) Safety devices for preventing closing o the doors when a passenger is entering or leaving a car~ one example of such a device being a so-called "safet~ edge" which usually contains a switch oper-able by an obstruction in the car doorway to cause the doors to re-open or at least stop further closing movement.

Fig. 1 illustrates schematically such a conven-tional automatic elevator system with the rectangle 1, and the dashed line rectangles 2, 3 and ~ represent, re-spectively, the door controls, car movement controls and door operating mechanism usually associated with such an elevator system. For the purposes of illustrating the first embodiment of the invention, it will be assumed that the system 1 has a sliding car door 6 and a sliding hoist-way or floor door 8 as illustrated in Fig. 2. However, it ~ ;
will be understood that the system may have a sliding cardoor 5 (Fig. 3) having two parts 6a and 6b and each hoist-way or floor door 7 may have two parts 8a and 8b as illu-strated in Fig. 2. Xt will also be assumed that there is a motor driven door operating mechanism at the top of he elevator car 9 whi.ch opens and closes both the car and the . . ~..~ . . .
hoistway doors 6 and 8 under control of the door controls 2, and the door controls 2 include a safety edge switch with cont~acts SE which, when at least momentarily closed, normally cause the car and hoistway doors 6 and 8 to re-open and after reaching full open positions, again movetoward their closed positions.

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In the elevator system assumed Eor purposes of il-lustration, it will also be assumed that the elevator car travels between three floors, although there may b e a greater or lesser numher of floors and that there also are switches at each floor providing at least a pair of con-tacts DLl, DL2 and DL3 which are closed when the locking mechanism for the doors, operable in conjunction with the door operating mechanism 4, locks the doors so as to pre-vent manual opening thereof. Thus, there are contacts DLl at one floor, contacts DL2 at the second floor and contacts DL3 at the third floor which are open at a floor where the car is located when the doors are not closed and locked, but such contacts are closed when the doors are closed andlocked.
In addition, there is a switch having a pair of contacts GS
which are closed when the car door 6, also known as a "gate", approaches its ully cIosed position. The contacts DLl, DL2 and DL3 and GS are normally connected in series so that when .
they are all cIosed, circuits on the car controls 3 are com-pleted and the car 9 moves from a floor.
Such contacts GS normally are opened and closed by the car door but may be opened and closed by any means which corresponds in position with the position o the car door. In accordance with the invention, one or more cams 10 and 11 are added to the door operating mechanism 4 so that the~proj~c~ions 12 and 13 thereof correspond in posi-tion to the position~of the car door 5 and, respectively, operate the contacts 14 and 15 and the contacts 16 and 17 .
~; of a pair of micro-switches 18 and 19. The cam 10 operates the contacts 14 and I5, i.eO, closes the contacts 14 and opens the contacts 15 just before the door locking contacts .
:- _ 9 .
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at the floor where the car is located, e.g. contactsDLl, DL2, or DL3, are closed. The cam 11 operates the contacts 16 and 17, i.e., closes the contacts 16 and opens the contacts 17 just before the contacts GS are closed.
The relay DLP is connected in series with the con-tacts 15, the contacts DLl, DL2 ancl DL3, the contacts 16 and the contacts GS. Therefore, when all oE the con~
tacts are closed, the relay DLP is energized causing closing of its contacts DLP2 and DLP3 and opening of its contacts DLPl.
A relay GSP is connected in series with the contacts 17 and the contacts GS. Accordingly, when the contacts 17 and GS are closed, the relay GSP is ener~ized, which causes the closing of its contacts GSP2 and GSP3 and opening of its contacts GSPl.
The usual operation of the contacts DLl, DL2, DL3 and GS and the settings of the cams 10 and 11 in the preferred embodiments of the invention are such as ~o provide the fol-lowing sequence:
Contacts Operation DLl, DL2 ~ DL3 Open except when hoistway door ully closed and locked, which occurs when car door within 3/8 in. oE fully closed GS Open except when car door wi-thin 2 ins. of fully closed 14 Open except when car door wi-thin 3/4 in. of fully closed Reverse of 14 16 Open except when car door wi-thin 2 1/2 ins. of fully closed : :.

17 Reverse of 16 -~
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The examples of oper~tions given hereinafter il~
lustrate the operations with respect to one floor, but it is to be understood that the operations are the same at each ~loor at which the elevator car stops.

Normal Operal:ion Let it be assumed that the elevator system is operating normally, i.e., the contacts DLl, DL2 and DL3 and GS have not been interconnected either by manual opera-tion thereof or otherwise, and that the car and the hoist-way doors are open, the car 9 being stopped at the floor having contacts DLl. Contacts DL2 and DL3, at the second and third floors, will be closed because the hoistway doors at such latter floors are closed and locked. The car ~ovement controls 3 then complete circuits causing the door operating mechanism to move the doors 6 and 8 toward their closed positions, and as the car door 6 reaches a position within approximately 2 l/2 ins. of its fully closed position, the contacts 16 close interconnecting the GS and DL7 contacts and the contacts 17 open thereby opening the energizing circuit for the relay GSP.
As the car door 6 reaches ~he position within approxi-~ately 2 ins. of its ~ully closed positionJ the contacts GS
close. As th~ car door 6 then reaches a position within approximately 3/4 in. from its ~ully closed position, the con-tacts 14 close ancl the contacts 15 open, the opening of the contacts 15 interrupting the energizing circuit for the re-lay DLP. Thereafter, when the hoistway 8 becomes fully closed and the car door 6 is within 3/8 in. o~ its fully closed position, t:he contacts DLl close completing the circuit ~or the starting of the car 9 by way of contacts GS, 16, DLl, D~2, DL3, 14, GSPl and DLPl.

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Car Door Contacts Interconnected Let it next be assumed that the car 9 is ~topped at the first floor with the car and hoistway doors open. Let it also be assumed that the car door contacts GS have~ either been manually operated or by-passecl, e.g., by a shunt or short, and the car hoistway doors commence to close. When the car door 6 and the hoistway door 8 have reached posi-tions approximately 2 1/2 ins. from their fully closed posi-tions, it is physically impossible to gain access to the gate or car door switch which includes the contacts GS.
However, if the contacts GS are closed or by-passed prior to the time that the doors 6 and 8 have reached such posi-tion, hence, prior to the time that the contacts 16 close and the contacts 17 open, the relay GSP will be energized through the contacts GS, or the by-pass thereof, and the contacts 17. Energizing of the relay GSP will open its contacts GSPl, thereby interrupting the car starting circuits of the controls~`3, and will close its contacts GSP2 which are in parallel with the safety edge contacts SE, the closing of the contacts GSP2 causing the doors to re-open and remain open until the contacts GS are opened or the by-pass thereof is removed. In the preferred embodiment o~
the invention, the relay GSP has contacts GSP3 which are con-nected to a well-known type of alarm system 22, e.g., a bell or buzzer with an energizing source, and when the contacts GSP3 are closed, by reason of the energization of ~he relay GSPi the alarm will sound.
The contacts GSPl are desirable to make certain ;
that the car starting circuits are open when there is tamper-30 ing with the switah which controLs the contacts GS, but it -will be noted that if the contacts DLl have not been tampered ~ , ;

with, the car 9 will not start because movement of the car door 6 toward closing will have been reversed before the contacts DLl close normally. Also, such movement oP the car door 6 will have been reversed prior to the closing of the contacts 16 which are in the car starting circuits. For these reasons~ the contacts GSPl may be omitted if the added safety thereof is not desired.

Door Locking Contacts Inter_onnected _ Again let it be assumed that the car 9 is stopped at the first floor with the car and hoistway doors open. ~hen the car door 6 is in the process of closing and reaches a point approximately 3/4 in~ from its fulIy closed position, it is impossible to physically gain a~cess to the door interlock which controls the contacts DLl. If, however, the contacts DLl are closed or by-passed before the car door reaches a position 3/4 in. from its fully closed posi-tion, the contacts GS, which close when the car door is within 2 ins. of its fully closed position, will complete a circuit through contacts GS, 16, DLl, DL2, DL3 and 15 for energization of the relay DLP, it being noted that the contacts 15 do not open until after the contacts GS close.
When the relay DLP is energized the contacts DLPl open, thereby interrupting the car starting circuits of the con-trols 3, and the contacts DLP2 close, the contacts ~LP2 be-ing in paralIel with the safety edge switch contacts SE and causing the doors to reverse and move to their open positions.
Preferably, the relay DLP has a pair of contacts DLP3 connect-ed to the~alarm system 22 and causing the alarm system to operate when the~contacts DLP3 are closed.

As the do~r 6 re-opens, after closing of the con-tacts DLP2, it will continue to move to its fully open : :; ~ : : : .
~ - 13 -position but the contacts GS are opened as the door moves towards its fully open position. Such opening of the con-tacts GS de-energizes the relay DLP which will permit the doors 6 and 8 to again move toward their closed positions after they reach their fully open positions, but if th~
contacts DLl are still closed or by-passed, the relay DLP
will re-energize as before ~nd the doors 6 and 8 will again re-open and then try to close. However, the elevator car 9 will not leave the floor because when the contacts GS are closed, the contacts DLPl are open and do not close until the contacts GS open. Furthermore, although the contacts DLPl make certain that the car 9 does not start, ~hey may be omitted if desired because door movement is reversed before the contacts 14 close and closing of the contacts 14 is required to complete the car starting circuits.
Accordingly, in the preferred embodiment of the inven-tion for an elevator system ha~ing a sliding hoistway door and a sliding car door, movement of a car from a floor is prevented if either the door interlock switch contacts at the rloor, e.g., DLl, DL2 or DL3 or the car door switch con-tacts GS are closed or shunted before the doors reach posi-tions which prevent physical access to such switches from the car or the doorways. If the contacts GS are so closed or shunted, the doors open and remain open. If the door inter-lock switch at the floor are closed or shunted, the doors open . . .
to their fully open positions r again commence to close, reverse their direction of movement, etc. In addition, if the door interlock switch or the contacts GS are closed or shunted, an alarm sounds. However, it will be apparent to~those skilled in the art that if it is desired to omit protection against closing or shunting of the door interlock switch contacts or . , .

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the contacts GS or the sounding of an alarm, the circuits, switches and contacts associated with such features may be omitted. Similarly, other types of door operation may be initiated by the controls of the invention, or if desired, the doors may be permitted to close without permitting de-parture of the car by omitting the DLP2 and GSP2 contacts.
As a Eurther aid in preventing closing of the car door 6 without simultaneous closing of the hoistway 8, the car door 6 may be provided with a projection 30 and the hoistway door 8 may be provided with a projection 31 engage-able with the projection 30, as shown in Fig. 2, so that the car door 6 cannot be closed unless the hoistway door 8 also closes. Thus, assuming that both doors close in the direction to the right as viewed in ~ig. 2, car door 6 cannot be closed unless the door 8 also closes, because of the projections 30 and 31. With such projections 30 and 31, the car 9 cannot start from the floor unless the door 8 is closed and the : door 8 cannot be held Qpen to pe`rmit access to switches and other apparatus on the car 9 when the door 6 closes.
Similarly, as shown in Fig. 3, the car doors parts 6a and 6b and the hois~way door parts 8a and 8b may be pro-vided with interengageable projections 30a, 31a, 32 and 33 which prevent closing of the door 5 without closing o~ the ; door 7. With:such interengageable projections 30-33 the car 9 will not start from a ~loor unless the door 7 is closed.

Conventional Swinging Hoistway Door System and Modification _ Fig. 4 i]Llustrates a conventional automatic elevator system similar to the system shown in Fig. 1, except for the : 30 modifications the~reof required to permit employment thereo~
in an elevator installation in which the hoistway door is a swinging door and is manually operated rather than operated :: j . , . ... . : . - . : -by the car door operating mQch.an;sm o:E the car 9. The car movement controls of the system shown in Fig. 4 differ from the car movement controls in the system shown i.n Fig. 1 mainly in the addition of the contacts HDl, HD2 and HD3, con-trolled by the hoistway doors, contacts HDl being at floor 1, contacts ~ID2 being at floor 2 and contacts HD3 being at floor 3.
In normal operation of the system shown in Fig. 4 without the modifications of the invention, the contacts HDl-HD3, GS and DLl-DL3 are connected in series so that it is necessary that all of such contacts be closed before the car 9 can move from a floor. Thus, if the hoistway door, the car door and the door interlocks function in their intended manner, the elevator car 9 is permitted to move from a floor.
In the preferred embodiments of the invention, such a conventional elevator system is modified to add the cams 10 and 11 operable by the car door operating mechanism 4 and a pair of micro-switches 18 and 19 operable, respectively, hy the cams 10 and 11. The normal interconnection between the contacts DL3 with the conventional car movement controls are interrupted and the contacts DL3 are connected in series with the contacts 14. The contacts 15 and 17, respectively, control energization of the relays DLP and GSP respectively having the contacts DLPl and DLP2, and the contacts &SPl and GSP2 : The modification of the conventional elavator system ~ also includes the addition at each floor of a switch 23 :: having contacts 24, operakle by a cam 27 secured to the .
swinging hoistway door 28 (Fig. 4) so as to rotate as the hoi~tway door 28 opens and closes. The switch 23 preferably ~: : is mounted in the hoistway above the hoistway door, it being ~' .:: .. . ., ,: ' ' .,, : : ' . "

understook that there i9 one such swi-tch 23 Eor each such hoistwa~ cloor 28, and preferahly, the switch 23 and the cam ~7 are enclosed in a -tamper~proof housing illustrated by the dotted ractangle 29. The contacts of each switch 23 are connected in parallel with each other, and all contacts are open when all hoistway doors are closed~
Each of the contacts 24 control -the eneryization of a relay DCP having contacts DCPl, DCP2 and DCP3. The contacts DCPl and DLPl are connected in series with a relay DO which has contacts DOl and DO2 connected, respectively, to the car door opening circuit and to the car door closing circuit of the door controls 2.
In the preferred embodiment of the invention, the contacts DCP2, DLP2 are connected to an alarm system 22 so that when any one of such contacts is closed, khe alarm system 22 operates.
The usual operation of the contacts DLl-DL3, GS and HDI-HD3 and the settings of the cams 10, 11 and 27 in the preferred embodiment of the invention are such ko provide the following sequence:

Contacts ~
HDl - ~ID3 Open except when hoistway door su~stantially closed GS Open except when car door within 2 in. of fully closed DLl - DL3 Open except when car door within 1/2 in. of fully closed; indicake locking of hoistway door 14 Open except when car door within 1 in. of fully closed Reverse of 14 ; 16 Open except when car door within 2 1/2 ins. of fully closed.

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Contacts o-E-~erat-: _ 17 Reverse o~ :L6.

24 Closed except when hoi.st~
way door within 3/4 in.
of fully closed.

Normal Operation Let it be assumed that the ele~ator system is operat-ing normally, i.e., the contacts DLl-DL3, GS and HDl-HD3 have not been interconnected either by manual operation or other-wise, that the car and hoistway doors are open and that thecar 9 is stopped at the first floor. ~s the passenger enters the car and hoistway door 28 is closed, the con~acts 24 open and then the contacts HDl close. The priox opening of the contacts 24 prevents energization of the relay DCP, but when the contacts HDl close, ~he relay DO energizes opening the car door opening circuit a~ its contacts DOl and readying the car door closing cixcuit at its contacts D02. Thereafter, by the pressing of a car button or the existence of a floor call, the car movement controls 3 cause the door controls to ~0 commence closing of the car door 6. Prior to the closing of the doors contacts G~ the cam ll operates the switch l9 closing the contacts 16 and opening the contacts 17, the opening of the contacts 17 interrupting the energization circuit for the relay GSP. As the car door 6 continues to .
close, the cam 10 operates the switch 18 closing the contacts 14 and opening the contacts 15, the opening of the contacts .
15 intexrupting the energizing circuit for the relay DLP.

Thereafter,~ the co~tacts DLl close completing the circuit in the car movement controls 3, which causes the car 9 to start from the floor.

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Hoistway Door Contacts Interconnected Again let it be assumed the the car 9 is stopped at the first floor with the car ancl hoistway doors open. When the hoistway door 28 reaches a point approximately 3/4 in.
from its fully closed position, it is not possible to gain access to the contacts HDl. If, however, the contacts HDl are interconnected or closed before the hoistway door reaches a position approximately 3/4 in. from its fully closed posi-tion, the contacts 24 which are closed, complete an obviousenergizing circuit for the relay DCP which closes its contacts DCP2 and DCP3 and opens its contacts DCPl. The contacts DCP2 operate the alarm system 22 and the contacts DCP3 complete a holding circuit for the relay DCP. The contacts DCPl, being open, interrupt the energizing circuit for the relay DO, which keeps the car door open circuit in the door controls 2 ener-gized by-way of the contacts DOl. Therefore, the car 9 is prevented from leaving ~he floor, and the car 9 can be placed back into operation only by opening the hoistway door 28 and opening and removing the malfunction of the contacts HDl.

Car Door Contacts Interconnected Let it be assumed that the car 9 is stopped at the first floor with ~he car and hoistway doors open and that prior to the time that the car door 6 reaches a posi-tlon, such as within 2 ins. of its fully closed position, the car door contacts GS have been closed or interconnectedO
When the hoistway door 28 is closed, the contacts 24 pre-vent energizatlon of the relay DCP permitting energization of the relay DO and readying of the car door closing cir-cuit.

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If the car door switch contacts GS have been closed or interconnected before the cam 11 operates the switch 19 and closes the contacts 16 and opens the contacts 17, the relay GSP will be energized causing opening of its contacts GSPl and closing of its contacts GSP2. The opening of the contacts GSPl de-energizes the relay DO completing the car door opening circuit at its contacts DO2~ Accordingly, the car door 6 will open and remain open as long as ~he contacts GS are closed or interconnected. The contacts GSP2 will activate the alarm system 22, and as long as the relay DO
remains de-energized and the car door is open, the car will be prevented from starting from the floor.

Hoistway Door In-terlock Contacts Interconnected Let it be assumed that the car 9 is stopped at the first floor with the car and hoistway doors open, and that prior to the time that the car door 6 reaches a position within approximately 2 ins. of its fully closed position, the contacts DLl have been closed or interconnected~ In the initial stages of door closings, the closing of va-rious switches will be as described in connection with the normal operation of the system, but when the door is approx- -imately 2 ins. from its fully closed position, the car door contacts GS will completej by way of the contacts 16 which have been closed previously by the cam 11, the closed con-tacts DLl~DL3 and the still closed contacts 15, a circuit for the energization of the relay DLP. Energization of the relay DLP will de-energize the relay DO by way of the con-tacts DLPl, which will cause the car door 6 to open as des-cribed hereinbefore. The contacts DLP2 of the relay DLP
will cause the ala:rm 22 to soundO
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- : , As the car door 6 opens, the contacts GS will open which will cause the relay DLP to de-energize and, therefore, if the door locking contacts DLl-DL3 remain closed or inter-connected, the car door 6 may again start to close after it reaches its fully open position, clepending upon the nature of the door controls in the elevat:or system. As long as the contacts DLl~DL3 remain closed or interconnected, the car door 6 will continue to open and then move towards its closed position, but the elevator car 9 will not be permitted to move from the floor.
Accordingly, in the preferred embodiment of the invention for an elevator system having a swinging hoistway door and a sliding car door, movement of a car from a floor is prevented if either the hoistway door contacts HDl, the car door contacts GS or the hoistway door interlock contacts DLl are closed or shunted before the doors reach positions which prevent physical access to such switches from the car or the doorways. If the hoistway door contacts HDl or khe or the car door contacts GS are so closed or shunted, the car door 6 opens and remains open. If the door inter-lock contacts DLl are so closed or shunted, the car door 6 opens to its fully open position, again commences to close, reverses its direction of movement, etc. In each case, the alarm system 22 sounds. However, it will be apparent to those skilled in the art that if it is desired to omit any one of the protecti~e features, such ~eature may be omitted by omitting the switches andl contacts associated with the omit~ed feature.
Similarly, other types of door operation may be initiated by the controls of the invention.
Al~hough preferred embodiments of the present in-vention have been illustrated and described, it will be ' .

s~

apparent to those s]cilled in the art that various modifica~
tions may be made wlthout departing from the pr.inciples of the invention.

WHAT IS CLAIMED IS:

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Claims (9)

1. In an automatic elevator system having an eleva-tor car with a car door, means mounting said car in a hoist-way extending between a plurality of floors in a building, a floor door at each of said floors for providing access to said car, control means including hoisting apparatus for moving said car from one of said floors to another and stopping said car at a floor, door operating means for automatically open-ing and closing at least said car door when the car is at a floor and switch means operable in accordance with the posi-tions of said car door and each said floor door for controlling said control means and permitting said control means to move said car from said floor to another when said car door and each said floor door is closed, the combination therewith of further switch means operable in accordance with the position of at least one of said car door and said floor door and normally operable prior to the operation of at least part of said first-mentioned switch means, and means connecting said further switch means in circuit with said control means for preventing movement of said car when said part of said first-mentioned switch means is operated prior to operation of said further switch means.

2. A system as set forth in claim 1, wherein said part of said first-mentioned switch means comprises a switch operable when said floor door is at least substantially closed.

3. A system as set forth in claim 1, wherein said part of said first-mentioned switch means comprises a switch operable when said car door is substantially closed.

4. A system as set forth in claim 17 wherein said system comprises locking means for automatically locking at least one of said car door and said floor door during movement of said car and for automatically unlocking at least said one of said car door and said floor door when said car is stopped at a floor, wherein said first mentioned switch means comprises locking switches operable by said locking means and wherein said part of said first-mentioned switch means comprises said locking switches.

5. A system as set forth in claim 1, wherein said floor door and said car door are mounted for sliding movement, said door operating means automatically opens and closes both said car door and the floor door at the floor at which the car is stopped and said first-mentioned switch means comprises first contacts which close when said car door is substantially closed and second contacts which close when both said car door and said last-mentioned floor door are closed, said first con-tacts being said part of said first-mentioned switch means and said second contacts being another part of said first-mentioned switch means, and wherein said further switch means comprises first switch means operable prior to normal operation of said first contacts as said car door closes, second switch means operable prior to normal operation of said second con-tacts as said car door closes, relay means controlled by said first switch means and said second switch means and including relay contacts, and means connecting contacts of said relay contacts in circuit with said control means.

6. A system as set forth in claim 5, further com-prising alarm means and means connecting contacts of said re-lay means to said alarm means for operating said alarm means when one of said first and second contacts is operated prior to operation respectively of said first and second switches.

7. A system as set forth in claim 1, wherein said car door is mounted for sliding movement and said floor door is mounted for swinging movement, said door operating means automatically opens and closes said car door at the floor at which the car is stopped and said first-mentioned switch means comprises first contacts which close when said car door is substantially closed, second contacts which close to indicate locking of said floor door and third contacts which close when said floor door is substantially closed, said first con-tacts being said part of said first-mentioned switch means, said second contacts being another part of said first-mentioned switch means and said third contacts being a further part or said first-mentioned switch means, and wherein said further switch means comprises first switch means operable prior to normal operation of said first contacts as said car door closes, second switch means operable prior to normal operation of said second contacts, third switch means operable prior to normal operation of said third contacts, relay means controlled by said first switch means, said second switch means and said third switch means and including relay contacts, and means connecting contacts of said relay contacts in circuit with said control means.

8. A system as set forth in claim 7, further com-prising alarm means and means connecting contacts of said relay means to said alarm means for operating said alarm means when one of said first, second and third contacts is operated prior to operation respectively of said first, second and third switches.

9. A system as set forth in claim 1, wherein said control means comprises door opening means for causing said door operating means to open at least said car door and said further switch means is connected in circuit with said door opening means for energizing the last-mentioned means.