Note: Descriptions are shown in the official language in which they were submitted.
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
~;
~4-
: : ~
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.
.
, . . . : . :
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.
~5a- :
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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;
. . .
--6
- ., ,: .
- - : : . . ~ . . : - .
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.
- 8 -
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~5~
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
.
:~: : : :
, . -
.
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 -~
.
~: :
-- 1 0 -- .,
.
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33\f~
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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:
D
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
~ ,
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;
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
- 14 -
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S ?;~
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
15 -
:: 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
~'
-- 1 6
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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.
17 -
~p~
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
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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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