US 2200074 A
Description (OCR text may contain errors)
y 1940. E. M. BOUTON 2.200.074
ELEVATOR DOOR OPERATING SYSTEM Filed June 22, 1939 3 Sheerts-Sheet 1 0 mm Wm WM w /W WITNESSES M [5M W y 7, 1940. I E. M. BOUTON 2.200.074
' ELEVATOR DOOR OPERATING SYSTEM Filed June 22, 1959 5 Sheets-Sheet 2 ll I l I II I I: z i n I II I I II I i 168 67 I Jmu/af/an.
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1 BY 6 W ToRiEY Patented May 1, 1940 UNITED STATES PATENT OFFICE inghonse Electric Elevator Company, Jersey City, N. 1., a corporation of Illinois Application June 2:, 1939,8erial 110.280,!
9 Claims- (Cl. 187-57) My invention relates to elevator systems, and more particularly to the door locking devices for interlocking the hatchway doors thereof with the control system for the cars.
g In many elevator installations in which the hoisting motor is operated by means of a motor generator set, it is usual to provide push buttons in each car for shutting down the motor generator set associated with the car. 7 when the doors 10 are operated by toggle lever arms, they are locked shut when closed, not only by the straight-line action of the toggle levers, but also by an interlocking door lock. In many of these installations the hatchway door locking latches are released 16 by electro-magnetic devices into locking position when the car makes a stop at a floor. I
Usually a service key is provided for moving the toggle levers out of the straight-arm position and an emergency key is provided for unlocking the ,0 locking latches on the hatchway doors. Heretofore in such installations, it has been impossible, with the car at the parking floor, to shut down the motor generator set from within the car, leave the car and close the doors,-without making it as necessary to use the emergency key to unlock the doors, unless a button is installed in the corridor at the parking floor to start the motor generator set and thus cause the locking latch to be released from its locking position. The installation of 80 such a starting button involves expense in running an alternating current riser from that floor to the penthouse and other difllculties.
Hence, it is an object of my invention to provide an elevator door operating system for an eleaii vator having a motor generator set, in which the car may be parked at a parking floor, the motor generator set shut down by operating a button in the car and then the hatchway doors closed, without causing the lock thereon to be locked in 40 such manner as to require both a service key and an emergency key to be used to regain admittance to the car.
Another object is to provide an elevator door operating system in which it will not be necessary 45 to install a motor generator set starting button in any corridor leading to the car.
A further object is to provide a simple and inexpensive but accurate auxiliary means for pre-- venting the locking of the interlock on the hatch- 60 way doors at a parking floor when'the car is stopped at that floor, the motor generator set shut down, and the hatchway door closed.
A still further object is to facilitate the rapidopening of doors to start up a car: and insure ss the opening of the door safety circuit, by opening the doors before th M. a. set is started, through means located within the car, operable by an attendant.
For a better understanding of the invention. reference may be had to the accompanying draw- 5 ings, in which:
Figure 1 is a diagrammatic representation of anelevator system withwhich my invention may be used.
Fig. 2-is a view in front elevation of a corridor door for the car shown in Fig. 1 with a door operating mechanism and an interlock therefor. I
Fig. 3 is a view in side elevation of the interior construction of the door interlock embodied in Fig. 2 with the locking latch in looking position.
Fig. 4 is a bottom plan view of the interlock shown in Fig. 3.
Fig. 5 is a view in side elevation of the interlock corresponding to Fig. 3 but with one of the switches eliminated for the sake of simplicity and with the locking latch held in its open position by an auxiliary device in accordance with my invention;
Fig. 6 is a view taken along the line VI-VI of Fig. 5.
Fig. 7' is a diagram in the straight-line style of the control system for operating the doors of the elevator system shown in Fig. 1, and
Fig. 7A is a key representation of the relays embodied in Fig. 7. 80
The relays in Fig. 7A areillustrated with their coils and contact members disposed in horizontal alignment with their positions in the straight-line circuits of Fig. I, so that their locations therein may be readily determined.
FThe following relays are used in the circuits of OR=door opening relay.
CR=door closing relay.
lN=lock-releasing coil at first floor. 2N=lock-releasing coil at second floor. 3N=lock-releasing coil at third floor.
T=inductor relay coil on car. K=interlocking relay. M=car running relay. 5
S=motor-generator starting relay. L=auxiliary latch coil.
Referring more particularly to Fig. 1' of the drawings, I have illustrated an elevator system as comprising a car Iii suitably suspended by a cable ii passing over a hoisting drum I! to a suitable counterweight I}. The hoisting drum is directly coupled to a hoisting motor It by a shaft ii. A variable voltage system of control, such as a Ward-Leonard system, is provided for operating 86 the hoisting-motor l4 wherein the motor is operated by a suitable generator I! mounted upon a shaft l8 driven by a motor It. The motor it also drives an exciter for supplying energy to trated as a three-phase alternating current motor which may be connected to any suitable source of power by means of the supply conductors I, II and III A motor generator starting relay 8 is provided for starting and stopping the motor gen erator set. A "start" button 8 2 and a stop button 82A are mounted in the car for controlling the relay 8 so that the attendant may start or shut down the motor generator set from within the car.
The car is provided with a door or gate 23 and each fioor landing is provided with a hatchway door 24. A motor 0 having an armature CA and a field winding CF is mounted on top of the car for operating the car gate.
As illustrated in Fig. 2, the hatchway door 24 for the first floor comprises a pair of horizontally sliding door panels 25 and 28 suspended from an overhead track rail 28 by a plurality of hangers 29 so that they may be readily moved to the right along the track rail in opening the door. A pair of toggle levers 30 and 3| are pivotally mounted on the door panels for use in opening and closing them. A hand grip I2 is disposed on the side'of the armll to permit the arms to be operated manually when desired. The right-hand end of the arm 3| is pivotally attached to one end of an operating arm 33, the other end of which is pivotally attached to a frame I4 mounted on the side wall of the hatchway.
The door may be operated by a power device a represented by a motor IH, having its lower end pivotally attached to a bracket 31 on the lower end of the bracket 34. The motor is disposed to actuate a shaft or arm 39 attached to a bell lever 40 which, in turn. is secured by a link 4| to the operating arm 33. When the motor is operated in one direction the shaft 38 will move upwardly thereby operating the bell 'crank lever 40, the link 4| and the arm 33 to effect an opening of the door panels 25 and 28. When the motor is reversed, the shaft 39 is pulled downwardly to cause the arm 32 to efi'ect the closing of the door panels.
Although a motor is provided for each corridor door and the car gate. it is to be understood that the motors and their operating levers specifically are so designed that the doors and the gate may be moved by hand at any time, if unlocked.
Each hatchway door is operated by a similar motor, those for the second and third floor being indicated in Fig. 7 by the armatures 2-HA and 3-HA respectively.
The hatchway door motors and the car door motor are preferably of series wound direct current type. Their armatures and field windings are connected in series, with the armatures in parallel with each other and' with the field windings in parallel with each other. Each hatchway landing is provided with a switch disposed to be operated by an inductor relay T on the car when it stops at that landing, for connecting the field winding and the armature winding of the door motor at that landing to the door operating circuit.
The floor switch responsive to the inductor re- "!5 lay for the first flooris des g ed as IT. that for the second fioor as 2T and that for the third door as ST. The inductor relay is connected to be controlled by some means associated with the stopping of the car, such as a speed governor G. While the car is operating, the governor prevents energization of the inductor relay. When the car comes to a stop at a floor, the governor closes its contact members to energize the inductor relay for operating the inductor switch at that floor to prepare the door operating motor thereat'for operation.
The circuit for the car motor and the hatchway motors in Fig. 'I does not illustrate the resistors and various detailed refinements usually included in such circuits but further information regarding such details may be secured from the Ellis and McCormick Patent No. 1,934,590, issued November 7, .1933, if desired.
A door opening relay OR and a door closing relay CR are provided for controlling the operation of the gate and door operating circuit. These relays may be energized by a car switch (not shown) disposed in the car or they may be controlled by electrical connections to the car control system which will cause the car door and the hatchway door to open when the car makes a stop at a floor, and to automatically close when the car prepares to leave the floor.
' An interlocking lock for.ach hatchway door.
is provided in order that they may be interlocked with the car control system to prevent the doors from being opened while the car is not making a stop thereat and also in order to prevent the car from being operated while any door remains unlocked.
The interlocking lock for the hatchway door at the first floor is indicated by the numeral and is mounted on the bracket 34 by means of a plu-.
rality of bolts 46 (Fig. 3).
The lock comprises a cast metal frame or casing 50, having an upper slot ii and a lower slot 52 in which locking bar 4'! slides up and down when the motor IH opens and closes the door. A plate 53 is secured to the frame II in front of the slots to maintain the bar 41 in its vertical position therein. A pair of side plates 54 and 54a are also provided to cover the working parts. The upper end, of the bar 41 is pivotally connected to the end 48 of the door operating link 4| so that operation of the door to open position will pull the bar upwardly and closing the door will move the bar downwardly. The inner face of the portion of the locking bar within the easing is provided with a pair of locking notches I! and 58 disposed to receive a locking latch 57 while the car is not making a stop at that floor. The latch is formed with a hub III which is pivotally mounted in the casing on a cross pin 59. The hub 58 of the locking member is also provided with a weighted arm 60 which biases the latch 51 to its locking position.
An electromagnetic coil IN is mounted directly above the weighted arm 60 by means of a bolt 62 screwed into a cross-section 63 of the lock frame. When the coil is energized, it will attract the arm 60 and thereby move the latch 51 out of its locking position in the notch BI or 56'. When the coil is deenergized.-the force of gravity will cause the arm to move the latch into its locking position when the door is closed.. 'Ihe coil IN is electrically connected by conductors 64 attached to a terminal board I mounted in the upper portion of the casing 50 and leading through a conduit opening 66 in the top of theframe to the control circuits for the car. The ll coil IN is connected for operation by the inductor relay T on the car. When the car stops at a floor, the relay T is energized to close the circuit for energizing the coil IN.
In addition to locking the door when it is closed and placing the car in condition for operation, the locking latch also controls a pair of contact members IN! to keep the car from being operated until the door is locked. When the latch is in locking position, these contact members are closed to energize an interlocking relay K of the car control system to permit operation of the car. While the locking latch is in its unlocked position. these contact members remain open to prevent operation of the car. One of the contact members is mounted on the outer end of an insulating block 81, the inner end of which is securely fastened to a projecting arm 58 molded on the hub of the locking latch. The other contact member is mounted on an insulating block 69 secured to a bracket mounted in the lower part of the frame 50. The contact members may be connected in the circuit of the relay K through suitable conductors H and 12 running out of the casing 58 through a conduit I3.
The locks for the second and third floor doors are provided with operating coils 2N and 3N, locking latches 51-2 and 513 and contact members 2Nl and 3Nl, respectively, for locking, unlocking and interlocking them with the control circuit of the car. The circuit for the lock operating coils IN, IN, and 3N includes contact members U and D of the up direction and the down direction switches (not shown) which prevent energization of the coils to release the locks while the car is in operation.
In elevator systems it is customary to select one floor as the parking floor at which the car may be stationed when resting or out of operation. Usually the first floor is selected as the parking floor and the door at that floor is provided with a service key means to unlock its toggle levers and an emergency key means to unlock its interlocking lock.
In the system illustrated, the first floor is selected as the predetermined parking floor. When the door panels are closed, the straight-line position of the toggle levers 30 and 3| will lock the door against an opening movement by anyone in the corridor. In order to break' the straight arm locking action of the toggle levers, a keyhole 43 is provided in the panel 28 just above the pivotaljoint between the two levers so that a service key 43a may be inserted from the corridor 'side to break the toggle joint and thus permit the door to be opened from the corridor.
The emergency key means comprises an emergency releasing arm for raising the locking latch 51 out of its locking position when any condition requires the latch to be forcibly released. One end of the releasing arm is fixed on a pin 16 rotatably disposed in the side wall of the casing 58 and its other end is disposed under the arm 50 of the latch, so that anticlockwise rotation of the pin will cause the arm 15 to raise the arm 88 on the latch and thereby lift the latch out of its locking position. The means for rotating the pin comprises an arm 11 having its one end securely fixed to the outer end of the pin and its other end attached to a cable 18 extending upwardly along the side of the casing to an emergency box IS on the hatchway wall.
' The outer face of the emergency box may be provided with a glass cover (not shown) facing into the corridor so that the glass may be broken at any time to permit the use of an emergency key (not shown) for operating the cable to pull upwardly on the operating lever 11 and thereby cause the pin 18 to raise the emergency lever 15 to move the locking latch out of its locking position. A tension spring 88 having its one end attached to the outer end of the lever 11 and its other end to a screw 81 in the casing is provided for biasing the emergency lever away from the locking latch so that it will not engage the latch except the emergency key is used. Inasmuch as such emergency releasing devices are old and well known in the art, further description thereof will be omitted.
. A car running relay M is provided for conditioning the car control system for operation and to indicate that the motor generator set is operating. A condition-to-run button It and an emergency stop button E for controlling this relay are mounted in the car to be operated by the car attendant. A pair of field protective relay contact members Fl? and a pair of counterweight overspeed contact members PC are connected in the circuit of the relay M to prevent its operation under unsafe conditions.
If the operator shuts down the motor generator set, leaves the car and closes the doors. the toggle arms will move into their straightline position and lock the door sov that the door cannot be opened without the use of the servicekey to break the toggle joint. The shutting down of the motor generator set causes the energizing coil in the interlocking lock to be deenergized, thus permit ting the locking latch 51 to fall into its locking position. With the car at the floor and with the locking latch in looking position and the toggle arms in locking position, the door cannot be opened unless the motor generator set is started or unless the glass on the emergency box is broken and the emergency lock operated to release the locking latch in addition to using the service key to break the toggle joint of the toggle arms.
Heretofore, in order to avoid the necessity of using both the emergency key and the service key to gain entrance to the car, it has been customary to install a motor generator starting button in the corridor at the parking floor so that the door interlock will be released and the attendant may regain admittance to the car by using only the service key. The installation of a motor generator starting button in the corridor at the parking floor entails the expense and difficulty of running alternating current risers from the parking floor to the penthouse.
In order to avoid this expense and difllculty, I have provided a novel system including an auxiliary latch 83 (Fig. 5) operated by an auxiliary coil L for preventing the locking latch 51 from moving into its locking position when the car is parked at the parking floor, the motor generator set shut down and the door closed.
The auxiliary latch 83 is pivotally mounted by a pin 81 on a bracket 84 secured to the casing plate 53 in position to engage an auxiliary arm 85 molded on the hub of the latch 51 and extending through a slot 86 in the plate 53 when the latch 51 is in its open position. The left hand arm of the auxiliary latch extends horizontally to constitute an armature 88 for the auxiliary coil L. When the auxiliary coil is energized, it attracts the armature 88 and consequently pulls the auxiliary latch 83 away from the latch 51. When the auxiliary coil is deenergized, it releases the armature 88 and the weight of the armature biases the latch 83 to swing in above the arm 85 to prevent the latch 51 from closing. The
- erator set is running.
An assumed operation of the system is as follows. It will be assumed that the motor generator startihg relay 8, the interlocking relay K, the carrimning relay M, and the auxiliary latch coil L are energized, that the first fioor has been selected as the parking floor and that the car is moving down to the first floor, with the car gate and all the hatchway doors closed and locked.
' Assuming that the attendant on the car stops the car at the first or parking'fioor, then this action causes the governor G to close its contact members GI to energize the inductorecoil relay T on the car. Inasmuch as the car is at the first floor, the coil T operates the plate PI to close its contact members ITI, ITZ, and IT3 for the purpose of operating the door interlock for the first floor and for preparing the hatchway door motor at that floor and the car gate motor for operation. The closing of the contact members IT3 energizes the lock releasing coil IN of the door interlock by the circuit L+l, IN, ITS, U, D, L -I. The energized coil IN attracts the armature 60 and which moves the latch 51 out of its locking notch 55 in the lock. shaft The opening movement of the latch 51 unlocks the door and opens the contact members IN I, thereby deenergizing the interlocking relay, K which opens its contact members KI in the control circuit of the car to prevent operation of the car while the door is unlocked.
It will be assumed now that the car attendant or the car control system operates the coil 0Q to close its contact members 0Q I for energizing the door and gate opening relay OR by the circuit L+I, MI, 0R, OQI, CRI, 0L, L-I. The energized relay 0R causes the hatchway door at the first floor and the car gate to open, by openingits contact members ORI and closing 0R2, 0R3, CR4 and CR5. The closing of the contact members OR and CR5 energizes the motor C for opening the car gate by the circuit L+ I, 0R4, CF, 0R5, 13, CA, L-I. This motor now operates to move the car gate 23 to its open position.
The closing of the contact members OR! and CR8 energizes the door opening motor IH by the circuit L+l, 0R2, ITI, IHF, 0R3, Ti, IHA,-
IT2, LI and the energized motor moves the door to its open positio As the door reaches its open position, it opens the limit switch 0L in the circuit of the door relay OR, thereby deenergizing that relay and causing it to open its contact members to stop the door motor In and the car gate motor C.
The car is now standing at the parking floor with its gate open and the hatchway door at that fioor open and anyone may enter or leave'the car. However, it will be assumed that no one enters the car and that the car attendant desires ,to leave the car parked at that floor i'or a while.
Therefore, he presses the button 82A in the car to shut down the motor generator set and then leaves the car.
The pressing of the button 82A deenergizesthe relay S which opens its contact members -SI-S5 inclusive.
The opening of the contact members S5 deenergizes the car running relay M instantly which in turn opens its contact members M58, thus deenergizing the auxiliary latch coil L. The deenergized coll L releases the armature and the weight of the'armature causes the latch 88 to swing into position above the arm 88 on the locking latch 51 while it is still in its open position to prevent it from moving to its closed position, g
The opening of the contact members SI, 58 and s4 opens the circuit for the driving motor 1| causing it to shut down and thereby stopvthe operation or the generator I! and the exciter 28.
Inasmuch as the supply conductors L+ and L- are provided with energy fromthe exciter 20, the energization of the lock coil IN on the interlock at the parking fioor will fail gradually by reason of the gradual fall of the exciter voltage as the motor generator set slows down to rest. This slow decay in voltage causes the coil IN to hold latch 5'! upuntil after the auxiliary coil L drops the auxiliary latch 83 into position to prevent the latch 51 from moving into its locking position in the notch 58 or the notch II.
Hence it is seen that the predetermined time delay in the deenergization of the coil IN after the deenergization oi. the coil L gives the auxiliary latch 83 time to fall in above the arm ll before that arm is released by the coil IN'and thereby prevents the latch 51 from falling into its locking position if the door is closed while the motor generator set is shut down with the car at the parking fioor.
As the car attendant leaves the car, he closes the hatchway door by hand. The movement 0! the door to its closed position causes-the toggle levers 30 and 3| to fall into their straight-line position and this position of the toggle levers will prevent the hatchway door from being reopened until the motor IH is energized or the service key is inserted through the service keyhole I to unlock the toggle levers.
If it were not for the auxiliary latch 88, the closing 01' the hatchway door 24 would also cause the latch 51 to fall into the. locking notch II or 56 and thereby lock the door with the door lock in addition to the locking action of the toggle levers. However, as described above, the auxiliary latch 83 is now disposed above the latch 51 and prevents that latch from locking the door when it reaches its closed position.
It will be assumed now that the car attendant returns. In order to gain admittance to the car he does not need to unlock the door lock (because the latch 51 is not in locking position). All he needs to do to unlock the door is to use his service key to move the toggle levers from their locking position. It will be assumed that he does this and opens the door by hand, enters the car, and presses the MG-starting button 82 in the car to start the motor generator set into operation. The closed position of .the button 82 energizes the MG starting relay S which closes its contact members S5 to prepare the car running relay circuit for operation. The starting of the MGset causes the exciter to supply energy to the conductors L+I and LI and this-energizes the inductor relay T and the interlock relay K. The relay T operates the plate PI to close its contact members IT3 to energize the lock releasing coil IN.
It will be assumed now that the attendant presses the button R in the car to energize the car running relay M in order to condition the car control system for operation. Therelay M, energized by the circuit L+I, R, E, FP, Fc, SI, M, L- I. closes its contact members MI, M2. M8 I0 the unlocking coil IN to hold the latch 51 in its unlocking position.
It will be assumed now that the car attendant operates the car control system (not shown) to cause the car to leave the parking floor and in so doing causes the coil CQ to be energized to close its contact members CQI, thus energizing the door closing relay CR by the circuit L+l, M2, CR, CQI, ORI, CL, L-i. The energized relay CR opens its contact members CRI and closes CR2 to CR5, inclusive. The closing of the contact members CR4 and CR8 energizes the car gate motor C to close the car gate and the closing 01 the contact members CR2 and CR3 energizes the door motor iH to close the hatchway door. As the door moves to its fully closed position and the up direction switch (not shown) is operated by the car control system for moving the car upwardly, the contact members U open, thereby deenergizing the locking coil IN which causes the latch 51 to drop into its locking position in the notch 55 as the door reaches its fully closed position. The movement or the latch 51 into the notch 55 closes its interlocking contact members INI, thereby energizing the relay K through the circuit L+l, K, .lNi, ZNI, 3N1, L- l. The energized relay K closes its contact members Ki, thereby enabling the car to be operated away from the floor inasmuch as the hatchway door is closed and locked by the interlock 48.
It will be apparent from the foregoing description that I have provided a door operating system in which the car attendant may park the car at a predetermined floor and then shut down the motor generator set, leave the car and close the door and later on be able to return and reenter the car with the use of only the service key and without being required to open the emergency look. It will also be apparent that the emergency lock'will cause the door at the parking floor to be locked and interlocked with the car nmning system at all times when the car is away from that floor and that the auxiliary latch will prevent the interlock from looking the door only when the car is at that floor and the motor generator is shut down.
Although I have illustrated and described only one specific embodiment of my invention, it is to be understood that changes therein and modiiications thereof may be made without departing from the spirit and scope of the invention.
I claim as my invention:
1. An elevator door operating system tor a car operable by a motor generator set to serve a hatchway door, said system comprising a control device for starting and for shutting down the motor generator set. a lock for the door, and
means responsive to operation of the control device to shut down the motor generator set while the car is at said floor for preventing the look from looking the door when it is closed while the car is at the corresponding floor and the motor generator set is shut down.
75 2. An. elevator door operating system tor a car at the parking floor operable by a motor generator set to serve a hatchway doo said system comprising a locking latch for locking the. door when the car is not a stop thereat, an auxiliary latch for preventing locking operation of the locking latch, control means for conditioning the car for operation, and means responsive to operation of the control means to condition the car for operation for keeping the auxiliary latch out of its preventing position.
3. .An elevator door operating system for a car operable by a motor generator set for serving a hatchway door, said system comprising a control device for starting and for shutting down the motor generator set, a device for preparing the car for operation, a locking latch for the door, said latch being biased toward door locking position, an electromagnet for the locking latch,
means responsive to operation of the motor generator set and to the stopping of the car at the corresponding floor for energizing the electromagnet to move the latch to its unlocking position, an auxiliary latch biased toward engagement with the locking latch to prevent it from moving from its unlockedposition to its locking position, an auxiliary electromagnet for the auxiliary latch, means responsive to operation of the motor generator set and to operation of the car preparing device for energizing the auxiliary electromagnet to move the auxiliary latch out of its preventing position so that the door may be locked while the car is away from the floor.
4. An elevator door operating system for a car "operable by a motor generator set for serving a plurality of floors provided with hatchway doors, a lock at one of said said lock having a locking latch biased to its door locking position, an auxiliary latch pivotally mounted on the lock in position to normally swing into position to prevent the locking latch from moving from its open position to its locking position, an electromagnet for operating the auxiliary latch to move it out of its lock-preventing position, means for causing the electromagnet to be energized to attract the auxiliary latch while the motor generator set is running and means responsive to shutting down the motor generator set for deenergizing the electromagnet when the motor generator set is shut down to release the auxiliary latch into position to prevent the looking latch from moving into locking position while the motor generator set is shut down.
5. An elevator door operating system for a car operable by a motor generator set for serving a hatchway door, said system comprising a control device for starting and shutting down the motor generator set, a locking latch for locking the door, an electromagnet for the locking latch, means responsive to stopping the car at the corresponding floor for energizing the electromagnet to open the locking latch, an auxiliary latch biased to prevent the locking latch moving from its open doors for locking that door,
position to its closed position, an auxiliary elctrofrom the operation of the motor generator set, a-
locking latch for locking the door, an unlocking electromagnet, means responsive to stopping the car at the corresponding floor for connecting the unlocking electromagnet to the circuit to cause it to be energized to open the locking latch, an auxiliary latch 'for preventing the locking latch moving from its open position to its closed posiw tion, an auxiliary electromagnet, a relay for con- A necting the auxiliary electromagnet to the circuit for operating it to keep the auxiliary latch out of its lock-preventing position while the motor generator set is in operation, and means responsive to operation of the control device to shut down the motor generator set when the car is at the floor for operating the relay to disconnect the auxiliary relay magnet from said circuit and for disconnecting the motor generator set from its source of energy, the auxiliary electromagnet being deenergized before the deenergization. of the locking latch electromagnet whereby the auxiliary latch is moved into its lock preventing position before the locking latch is released by the locking latch electromagnet thus preventing the locking of the door when the car is at the floor and the motor generator set is shut down.
7. An elevator door locking system for a car operable to serve a door at a floor landing, said system comprising a locking latch, an electromagnet for moving the locking latch out of looking position, an auxiliary latch for preventing the locking latch from moving to its locking position, an auxiliary electromagnet for operating the auxiliary latch, means for connecting the electromagnets to sources of energy to cause them to attract the latches, and means for deenergizing first the auxiliary electromagnet and next the locking latch electromagnet when the car is at the floor to cause the latches to operate in a predetermined order.
8. An elevator door lock comprising a casing. a locking latch pivotally supported by the casing in position to normally assumeits locking position, an electromagnet mounted above thelatclr for moving it out of its locking position, a bracket mounted on the face of the casing above the locking latch, an auxiliary latch mounted on the bracket above the locking latch to normally prevent it from moving from its open position to its locking position, and an auxiliary electromagnet mounted on the bracket for operating the auxiliary latch".
9. An elevator door lock comprising a locking latch biased toward locking position, an electromagnet for moving the locking latch out of its locking position, an auxiliary latch biased toward engagement with the locking latch to prevent it from moving from its unlocked position to its locking position, and an auxiliary electromagnet for moving the auxiliary latch away from the locking latch.
EDGAR M. BOUTON. v