US3545572A

US3545572A - Elevator door control

Info

Publication number: US3545572A
Application number: US805287A
Authority: US
Inventors: Alan M Hallene; Henry J Holuba; John J Drexler
Original assignee: Montgomery Elevator Co
Current assignee: Montgomery Elevator Co
Priority date: 1967-08-18
Filing date: 1969-03-07
Publication date: 1970-12-08
Anticipated expiration: 1987-12-08

Description

I United States Patent [111 3,545,572

[72] Inventors Alan M. Hallene; [56] References Cited Henry J. Holuba; John J. Drexler, Moline, n- STATES PATENTS minds 2 900 521 8/1959 Eames 250/221 PP 805,287 3242341 1966 w d ITTI I Filed March 1969 3/ oo ward 250/22l Di i i f S N 661,655, Primary Examiner-Harvey C. Hornsby p t Attorney-Hofgren, Wegner, Allen, Stellman & Mc Cord Aug. 18, 1967, now 3,450,232 [45] Patented Dec. 8, 1970 [73] Assignee Montgomery Elevator Company ABSTRACT. An elevator control continuously moves a car a corporation of Dehware door thrlotilgh an opening and dclosing opleratiog, wlthoutbpausmg at a u open position, an moves t e car oor at su stantially different speeds to control the total door open time. The breaking of a photobeam across the doorway modifies the [54] ELEVATORSDOOR COIFTROL speed and direction of movement of the door. When the door 10 Claims 1 Drawmg photobeam circuit becomes inoperative, the speed of opera- [52] US. Cl 187/52, tion of the car door is modified until the condition is 250/215, 250/22] remedied. Should a door lock fail to unlatch, opening [51] Int. Cl B66h 13/02 direction power is discontinued and closing direction power is [50] Field of Search 187/28, 29. applied to the car door motor to reestablish electrical interlock contacts in the hoistway.

PAIENIEI] IIEC 8 I970 SIIEEI 2 [IF 9 CONVENTIONAL ELEVATOR STARTING. RUNNING 8| LEVELING CONTROLS 4s 4 I 7 DECELERATING CIRCUIT [:TARTING CIRCUIT CALL REGISTERING CIRCUIT ELEVATOR DOOR CONTROL DOOR OPEN TIME 8: SPEED CONTROL DISABLED PEC OVERRIDE MECHANICAL FAILURE OVERRIDE PHOTOELECTRIC CIRCUIT (PEC) \PATENIED DEC 8|97U 3.645572 SHEET I BF 9 FIG. 5 SHUNT FIELD W i O-| R-4 MoToR c 4 EEX-l RI RMATURE CLOS II R. SDR- 3 2 0-2 G RID DELAYED TDCL CLOSE DROP-OUT V LIMIT RELAY DCL c DE-l CLOSE l\/ m V SLOWDOWN EEX-2 04 soR OPEN SLOWDOWN 05 DE-2 o H OPEN jg LIMIT DOL LIGHT 501mg? 1 35 i::I I

'II" LIGHT BEAM pg ACROSS DOOR EIE E QE ES 3 y ENTRANCE WHEN PHOTOELECTRIC EI RQQE IE .l PHOTggELL {fig} AMPLIFIER E5 V NPUT T POWER I I L EARLY OPEN SLOWDOWN OX PATENTEU DEC 8197!] SHEET 5 [IF 9 FIGSA m W c m E IMTW H I. Lam

D E I l I I I l I I I I I I I I I I l I I I I I I I I I I i I I I I I I I I I I I I I I I I I I I I I I I I I CONT CONT CONT NT CONT CONT PATENTED 05c 8 I976 SHEET 7 0F 9 FIG6A PATENTEDBEB 8!.970 3545572 SHEET 8 BF 9 FIGTA ELEVATOR noon coN'rnoi.

RELATED APPLICATION This application is a division of our copending Pat. application Ser. No. 661,655, filed Aug. 18, 1967, now U.S. Pat. No. 3,450,232, entitled Elevator Door Control.

BACKGROUND OF THE lNVENTION This invention relates to an elevator control, and more particularly to a control for an automatic elevator car door.

Prior elevator door controls have met with limited success when operating under certain adverse conditions, such as heavy traffic demands in an underelavatored installation, or inoperative control circuits whichcause door operation to be partially or totally disabled until repairs can be undertaken.

For example, typical automatic elevator controls shorten the door open time of a fully open door when a photobeam is broken, to expedite car departure after load transfer. Such an installation does not take into account the basic problem involved in an underelevatoredinstallation, namely, an oversupply of passengers transferring at too slow a speed for the amount of traffic to be handled. The control fails to solve the problem because it merely operates the car door in conformity with the traffic flow which has already occurred, rather than attempting to provide some measure of control over the traffic flow itself.

Another adverse condition which at least partly disables an elevator control occurs when a photoelectric door circuit becomes inoperative, as by a light bulb becoming burned out. Prior elevator controls have continued to operate the door, as by cutting out all safety devices after the expiration of a long failure time period; but each door operation thereafter, until the circuit is repaired, is subject to the same disability, and passengers must wait for the expiration of the long failure time or the like at each floor before the elevator door will close. Such a control is intended only as a safety override, when smoke or the like blocks a photobeam, and is unsatisfactory to compensate adequately for circuit failures, some of which may not be of sufficient importance to warrant immediate repair.

A different type of disability occurs when a mechanical interlock for a hoistway door fails to unlatch at a floor. As opening direction power is applied through the car door to the hoistway door, electrical interlock contacts (generally in the hoistway) may become disengaged, even though the mechanical interlock has failed to open. in prior installations, such an occurrence renders the elevator system completely inoperative, since the elevator car is incapable of opening its door, and is unable to travel through the hoistway to other floors.

SUMMARY OF THE lNVENTlON The elevator door control disclosed herein overcomes disadvantages of previous controls by providing a measure of control over the traffic flow, both during normal operating conditions, and during abnormal conditions caused by mechanical, electrical or other failures. To expedite passenger movement, the door is continuously moved through an opening and closing operation, without pausing at its fully open position. It has been found that such operation urges passengers to transfer more rapidly. The total door open time is controlled by operating the door at a very slow or creep speed for a major portion of the time the elevator passageway is open to load transfer. Preferably, the creep speed operation occurs during the final opening movement of the door, since passengers are less hesitant to pass through the passageway while the door is opening away from them.

A load-sensing device, asa photoelectric circuit, modifies the door operation upon load transfer. According to one embodiment, when the car is not stopping for a hall call, and a passenger breaks a photobeam, the door immediately reverses its direction of movement and closes at creep speed until a short time after the beam is restored, when full closing speed occurs. Alternately, in another embodiment, when the car does not stop for a hall call and a passenger breaks the photobeam, the door does not immediately reverse direction on a photobeam break, but rather continues to open at a fast speed. bypassing the door open creep speed. In some circumstances, such as when the car stops for a hall call, a greater amount of time should be provided for load transfer. in such a case, the door operates at creep speed during the final opening movement, regardless of whether or not the beam is broken while the door opens. it has been found that the above described operation materially increases the speed rapidity with which passengers transfer between a landing and an elevator car. Many passengers tend to transfer rapidly while an elevator door is moving, as contrasted with relatively slower passenger movement when an elevator door remains at rest in a fully opened position.

Should the photoelectric circuit become disabled, as when the light bulb becomes burned out or dirt obstructs the photobeam, the door operation is modified to allow the doors to close within a reasonably short time interval. As the eleva tor car moves through the hoistway, a testing circuit determines whether the blocked photobeam at the previous landing was caused by normal passenger transfer, or by an abnormal condition, such as a circuit failure. If the blocked photobeam was caused by a circuit failure, the door operation is modified by opening the door fully at the conventional, or fast speed, and thereafter immediately closing the door at an intermediate speed.

Should a mechanical door interlock fail to unlatch when an elevator car is to open its door, the door-opening motor may produce a slight movement of the car door sufficient to open the electrical interlock contacts in the hoistway. The elevator system operation is maintained by discontinuing opening direction power and applying closing direction power to the door, causing the electrical interlock contacts to close. The elevator car will now continue service in a normal manner.

One object of this invention is the provision of an improved control for an elevator door.

Another object of this invention is the provision of an elevator door control which modifies the opening and closing operation of the door to overcome adverse operating conditions.

One feature of this invention is the provision of an elevator door control which continuously moves a door through an opening and closing operation. The speed of movement, preferably while the door is opening, controls the door open time.

Another feature of this invention is the provision of an elevator door control which modifies the door operation if a passenger enters or leaves during opening movement of a door by either stopping the door and immediately starting to close the door, or by causing the door to open fully at fast speed, bypassing the slower speed operation during the final opening movementof the door.

Yet another feature of this invention is the provision of an elevator door control which tests the operation of a load transfer detection circuit. If a failure has occurred, the control modifies the door operation to provide service without the functioning of a load detection circuit.

Still another feature of this invention is the provision of an elevator door control which recognizes when a mechanical door interlock fails to unlatch, and modifies the door operation, allowing the elevator system to continue to service the other floors.

Further features and advantages of the invention will be apparent from the following description and from the drawings.

BRIEF DESCRlPTION OF THE DRAWINGS FIG. 1 is a perspective view of an elevator car suitable for use with the door control of this invention;

FIG. 2 is a fragmentary plan view, taken along line 2-2 of HO. 1',

FIG. 3 is a block-diagram of the electrical control circuit for the elevator car door;

FIG. 4 is a series of diagrams of elevator door speed versus elapsed time, for opening movement of the door (solid lines) and for closing movement of the door (dashed lines), under different operating conditions, in which:

FIG. 4A shows door operation when the photobeam is not broken,

FIG. 4B shows door operation when the photobeam is broken during the fast speed opening of the door,

FIG. 4C shows door operation when the photobeam is broken during slow speed opening of the door,

FIG. 4D shows door operation when the photobeam is broken during fast speed closing of the door, and

FIG. 4E shows door operation when no photobeam is present (inoperative photoelectric circuit);

FIGS.57 are continuous across the line circuit diagrams for an elevator door control circuit embodying the invention; and

FIGS. A7A are key diagrams of the components in FIGS. 5-7, respectively.

DESCRIPTION OF THE PREFERRED EMBODIMENT General Operation In FIGS. 1 and 2, an elevator system is illustrated which is suitable for use with applicants invention. An elevator car is guided by hoistway rails 21 extending vertically along the sides of a hoistway for a single one or a bank of elevator cars. Car 20 is supported by a cable 22 connected to drive equipment (not illustrated).

The elevator car is positioned at a floor or landing 25, where load transfer occurs through a passageway or doorway between the landing and the elevator car. A car door 26 is moved through an opening and closing operation to expose and block the passageway to load transfer. While only a single door is illustrated, the invention is equally applicable to cars having double doors, each door being formed from one or more sections.

The passageway is also blocked to load transfer by a hoistway door 28 located at each landing 25. Car door 26 carries interconnecting apparatus 30 which latches with the hoistway door adjacent thereto to open the hoistway door as the car door is driven open. A hook 31, mounted on each hoistway door, mechanically engages a corresponding latch 32 located in the hoistway, to prevent the hoistway doors from opening unless the elevator car is adjacent that landing. When the elevator car door is to open, a conventional unlatch mechanism (not illustrated) becomes actuated to disconnect hook 31 from latch 32. Each latch 32 includes electrical interlock contacts which close when hook 31 connects with the latch. The contacts are connected in an elevator control circuit to prevent the car from running through the hoistway unless all the hoistway doors are closed.

A sensing device, mounted on car 20, determines when a passenger or other load is present in the passageway. Such a sensing device may comprise a light source 35 which projects a photobeam 36 across the passageway to a photoelectric cell 37. Photo beam 36 is positioned to be broken when a load is moved into the doorway.

The circuit illustrated in block form in FIG. 3 controls the operation of the elevator system of FIGS. 1 and 2. A suitable elevator control 40 initiates the starting, running and leveling operations of the elevator car. Control 40 includes a circuit 42 which registers hall calls from stations, 43, FIG. 1, and car calls from station 44, FIG. 2. A starting circuit 26 is responsive to one or more registered calls to cause the car to move through the hoistway in the proper direction. As the elevator car approaches a landing for which a call in the proper direction is registered, a decelerating circuit 48 slows the movement of the car, while a leveling circuit 50 levels the car to the landing.

The door is now opened and closed by elevator door control 60. A variable speed door motor 61 is initially under control of a door open time and speed control circuit 63. A photoelectric circuit (PEC) 64, which includes light source 35 and photoelectric cell 37 of FIG. 2, is responsive to the breaking of photobeam 36 to modify the movement of the door. Should PEC 64 become inoperative, as by light source 35 becoming burned out, or by smoke obscuring the photobeam, PEC override circuit 66 effectively disconnects PEC 64 and controls the operation of door motor 61 in a modified manner. When normal PEC operation is restored, override circuit 66 is automatically disconnected from further control over the operation of the door.

Door control 60 also actuates the previously described mechanical hoistway door unlatch mechanism (not illustrated) when the car door is to open. Should the hook 31 fail to unlatch, a mechanical failure override circuit 68 overrides the operation of door open time and speed control circuit 63 and modifies the normal opening operation of the door.

In the discussion of the circuit, the following letter designations will be used:

Relay: Door Motor Closing Power.

DCL Door Close Limit. DE Door Operator Pilot. DO Door Open Signal. DOL Door Open Limit. DOX Door Fully Open Signal. DS Car Call Button Operation. DT Door Reverse Signal. EE Photoelectric Beam Signal. EEX Slow Door Closing Signal. EEY Photoelectric Failure Sensing. EEZ Photoelectric Failure Memory and Medium Door Close Speed. HO Hall Call. LRA Leveling Zone Indication. O Door Motor Opening Power. OX Door Open Slow. RA Motion Indication. S Starting Signal. SAF Stop Switch Indication. SDR Door Motor Slowdown. TD Latch Timing Interval. TDA Door Timing Expires. TDAT Door Release Timing TDCL Delayed Door Close Limit Signal. UDC Car and Hall Call Pick-up Signal. Switch: SW12. and SWlb- Mode Transfer (ganged switches).

Relay contacts are identified by the letter designation of the relay followed by the number designation of the contact, as shown in the key, FIGS. 5A-7A.

Disabled Photoelectric Circuit Override The operation of disabled PEC override circuit 66 will be explained with reference to the door speed versus time diagram in FIG. 4E. The door operation is modified when a PEC failure occurs, such as a burned out light source lamp 35, or dirt or smoke throughout the hatchway being responsible for the degradation of the photoelectric beam 36. If the photoelectric circuit 64 first became inoperative while the door was moving across the passageway, the door would, at that landing, move to its fully closed position in the same manner as though the photobeam became blocked by load transfer.

As the elevator car travels through the hoistway, a testing circuit is responsive if the photoelectric cell has no output at this time, to record a failure of PEC unit 64, since nothing should be blocking the photobeam while the car travels through the hoistway. The recorded failure modifies the next operation of the door control, causing the door to open fully at its conventional, i.e., fast speed, whereupon reaching the full open position, the door immediately begins to close at an intermediate closing speed, between the fast closing speed and the creep closing speed. Such modified door operation, which occurs whether the car is stopped for a car or hall call, provides continuity of elevator service by providing optimum fixed door operation when the door control circuit cannot recognize load transfer.

All devices effecting door reopening, that is, the door open button, car call buttons, door safety edge contact, stop switch, and hall call button corresponding to the direction of travel of the car at the floor where it is standing, operate in a normal manner as when the photoelectric circuit is operative. Upon correction of the failure in the photoelectric circuit, .normal door operation is automatically restored.

The operation of disabled PEC override circuit 66 may be briefly summarized as follows. When photobeam 36 is broken, relay EE, FIG. 5, becomes energized. Contact EE-2, FIG. 6, closes to pick up relay EEX. As the elevator car begins to move through the hoistway, relays EEY and EEZ, FIG. 7, are picked up providing the beam remains broken at this time. Relay EEZ becomes selfiholding as the elevator car initiates its slowdown for the next stopping floor, setting up a memory function indicating a failure of the photoelectric circuit.

The elevator car opens its door fully at conventional speed. When the door reaches its fully open position, relay DOL drops out, opening contact DOL-2 which causes relay EEY to drop out.

The door now begins to close, as when the photobeam is blocked, except that relay contact EEZ-l, now open, disconnects resistor R-4 from the armature. As a result, the door closes at a medium speed, between the slow closing speed (when resistor R4 is inserted across the armature) and fast closing speed.

The brake is released as the elevator again travels through the hoistway, dropping out relay EEZ. Relay EEY now reevaluates the PEC failure. If the photoelectric circuit is still inoperative, relay EEY again becomes energized to initiate another modified elevator door operation, by setting up a memory function in relay EEZ. However, if the failure condition has been rectified, as by replacing a burned out light source, or because the elevator car has travelled past smoke which has obscured the photobeam, relay EEY is not picked up, and thus normal operating conditions are reestablished.

DETAILED DESCRIPTION Referring to FIGS. 57, a source of DC voltage (not illustrated) is connected across power lines and The supply for the elevator apparatus other than the DC door motor 61 could, however, be supplied from an AC voltage source, if desired.

The door operating mechanism utilizes a shunt wound DC motor 61, FIG. 5, the field of which is directly connected across the and power lines. The armature of motor 61 receives bidirectional power for opening and closing the mechanically interconnected hoistway and car doors, at different speeds, through various 0 and C relay contacts, and resistors R-l, R-2, R-3, R-4 and R-S. The door operating mechanism shown in FIGS. 1 and 2 provides for the cam operation of limit switches CLOSE LIMIT, OPEN LIMIT, CLOSE SLOWDOWN, OPEN SLOWDOWN and EARLY OPEN SLOWDOWN, in accordance with the position of the door.

The circuits in control 40 operate to close momentarily the CAR AND HALL CALL PICKUP contact, FIG. 6, to energize relay UDC whenever the car is conditioned to stop at a floor for a car or hall call. These same circuits operate to close momentarily the CAR AND HALL CALL PICKUP contact to energize relay UDC whenever an appropriate car or hall call button is pressed to cause the closing doors to reopen. Call registering circuit 42 operates to energize hall call relay HC when a hall call at the floor to which the elevator car is stopping has been registered, whether or not a car call has also been registered.

Starting circuit 46 operates to energize relay S, FIG. 7, when the car is conditioned to close its doors in anticipation of providing further service. Relay S remains picked up thereafter (unless the doors are caused to reopen) until the elevator initiates its slowdown after running to the next floor to be served, or, in the event that the car is to remain at rest at a floor, until the doors have fully closed and no direction preference remains assigned to the elevator.

The sequence of operation is as follows for a car call. As the. car is running through the hoistway, the CAR AND HALL PICKUP contact, FIG. 6, momentarily closes shortly before the car begins to slowdown for the car call. HALL CALL relay HC is deenergized at this time. When the CAR AND HALL CALL PICKUP contact closes, UDC momentarily picks up. UDC-l closes to pick up DO through TDA-l and DOL-l. DO seals in through TDA-l, DOL-l and DO-2.

A contact on the elevator brake closes to energize relay RA when the brake is released (car in motion), and opens when the brake is set (car stopped). Leveling unit switches on the car closes to energize relay LRA when the elevator is within the door opening zone of a floor where it is stopping or stopped.

As the car levels with the floor at which it has been conditioned to stop, it enters a door operating zone in which the car leveling unit switches, FIG. 6, close to pick up LRA. LRA-2 closes to pick up DE thru DO-3. DE-2 closes to pick up 0, FIG. 5, through OPEN LIMIT switch, which opens only when the door is fully open. O-] and 0-2 close, O-3 opens, and opening direction power is applied to the door motor through R-1, O-2, SDR-2, armature, and O-1-. The mechanically latched hoistway and car doors begin to open at normal speed.

As soon as the doors have moved away from the fully closed position, CLOSE LIMIT switch, which opens only when the door is fully closed, closes to pick up DCL and TDCL. As the doors reach a position 6 inches from full open, the EARLY OPEN SLOWDOWN switch, which closes only while the doors are within 6 inches of their fully open position, closes to pick up OX through DT-3 and 0-7. OX-l closes to connect the series combination of R-4 and R-S across the armature, causing the doors to slowdown.

As the doors approach the full open position, the OPEN SLOWDOWN switch, which closes as the opening doors near the fully open position, and remains actuated until the door subsequently closes beyond this slowdown point, closes to pick up SDR through O-5. SDR-l closes to parallel resistor R- 2 across the armature, and SDR-2 opens to insert resistor R-3 in series with the armature to reduce the applied armature voltage so that the doors further slowdown. When the doorsreach the fully open position, OPEN LIMIT opens to dropout O and DOL. O-l and O-2 open to remove opening power from the armature. O-3 closes to place a dynamic braking short circuit across the armature through C-4, and the doors stop at their fully open position.

As the doors reach the full open position, DOL-l opens to dropout D0, in turn opening DO-3 to dropout DE. DE-l closes to pick up C through CLOSE LIMIT. C-1 and C-2 close, 04 opens, and closing direction power is applied to the door motor through R-l, C-l, armature, SDR-2 and C-2. C-3 closes to parallel resistor R-Z across the armature. The doors start to close at normal closing speed. As soon as the doors have moved away from the fully open position, OPEN LIMIT closes to pick up DOL. When the doors have moved 6 inches away from the fully open position, the EARLY OPEN SLOW- DOWN switch opens without effect. As the doors approach the full closed position, the CLOSE SLOWDOWN switch, which closes as the closing door nears the fully closed position, and remains closed until subsequently opened beyond this slowdown point, closes to pick up SDR through CLOSE LIMIT and O-4. SDR-2 opens to insert resistor R-3 in series with the annature, reducing the applied armature voltage so that the doors slowdown.

When the doors reach the full closed position, CLOSE LIMIT opens to dropout C and DCL and to remove power from TDCL (which is delayed in dropping out). C-1 and C-2 open to remove closing power from the armature, C-3 opens to disconnect resistor R-2 from across the armature, and C-4 closes to place the dynamic braking short circuit across the armature through O-3. The doors stop at their fully closed position and the hoistway interlock contact 32, FIG. 2, is established as the hoistway door becomes mechanically locked by hook 31. Shortly thereafter TDCL drops out.

The photoelectric light source 35, located on one side of the doorway, FIG. 5, is powered across the and power lines. The light beam 36 emitted therefrom is directed across the doorway and impinges on photocell 37, mounted on the side of the doorway opposite the light source, so that a load entering or leaving the elevator car causes the light beam to be broken. The photocell 37 is connected to a photoelectric amplifier which derives its operating power from the and power lines. The photoelectric amplifier contains an output relay EE which becomes energized only when the photocell is dark.

The circuit is connected to operate in either the A or B mode according to the corresponding A or B position of a two section mode switch SW1. The mode switch consists of a first section SWla, FIG. 6, ganged to a second section SWlb, FIG. 7, to cause both sections to be simultaneously positioned at either the A or B position labeled in the drawings.

If the doors open to within 6 inches of being fully open without the beam being broken and the circuit is operating in the A mode, the doors will begin to close at normal speed instantly upon the pressing of any car call button 44. Pressing a car call button picks up relay DS through the third contact on the button, FIG. 6. DS-l opens to dropout DT. DT-2 closes to pick up TDA and energize TDAT, FIG. 7, through the A position of switch SWlb, DCL-5, and I-IC-Z. TDA seals in, and power is sustained on TDAT, through TDA-3 and TDAT-1. TDAT is energized, but is delayed in picking up. TDA-l opens to dropout DE and signal the door operator to close the doors according to the previously described sequence of operation. If the circuit was operating in the B mode, TDAT would not have been energized, due to an open circuit at SWlb.

If the doors open fully in the A mode without the beam being broken, or open fully due to operation in the B mode, or due to a hall call, the doors will instantly begin to close at normal speed upon reaching the fully open position. Upon the earliest interruption of the light beam, the doors will begin and continue to close at slow speed as long as the beam remains broken.

The interruption of the light beam after the doors have fully opened will cause relay EE, FIG. 5, to pick up and remain picked up as long as the beam is interrupted. OPEN LIMIT will have opened to dropout DOL, opening DOL-l to dropout DO. DO-I opens to dropout DT. DO-3 opens to dropout DE which signals the door operator to close the doors according to the following sequence of operation.

C-1 and C-2 close and C-4 opens. 03 closes to connect resistor R-2 across the armature. EEX-1 closes to connect resistor R-4 across the armature through O-3, -6, and EEZ-l. EEX-2 closes to pick up SDR through CLOSE LIMIT and O- 4. SDR-2 opens to insert resistor R-3 in series with the armature. Closing direction power is applied to the door motor through R-l, C-l, armature, R-3 and C-2. Resistors R-2 and R-4 are now connected across the armature and resistor R-3 is connected in series with the armature so that a greater voltage drop appears across R-l, with a corresponding lower voltage across the armature than when the doors were to close at normal speed. The doors begin to close at slow speed. If the beam is not reestablished during the door closing sequence, the doors will continue to their fully closed position at the slow speed.

If the beam is reestablished while the doors are closing at slow speed, the doors will continue to close at slow speed for a short time interval, about 2 seconds, after the beam is reestablished, after which time they will resume normal closing speed.

Reestablishment of the beam while the doors are closing at slow speed will cause relay EE to drop out. EE-2 opens to remove power from delayed dropout relay EEX, FIG. 6. After a short time interval, EEX drops out. EEX-2 opens to dropout SDR, FIG. 5 (provided the CLOSE SLOWDOWN position has not already been reached). SDR-1 opens without producing any effect, because closed C-3 is in parallel with it. SDR-2 closes to short circuit resistor R-3, previously connected in series with the armature. EEX-I opens to disconnect resistor R- 4 from across the armature. A higher voltage is now developed across the armature and the doors resume their normal closing speed. Operation thereafter is the same as was previously described for a normal door closing cycle.

Should the beam be broken again, before the doors have fully closed, the doors will instantly reduce their closing speed to the slow speed upon the interruption of the beam. The subsequent interruption causes EE to pick up, closing EE-2 to pick up EEX. EEX-2 closes to pick up SDR. EEX-1 closes to connect R4 in parallel with the armature through EEZ-l, O- 3, and O-6. SDR-2 opens to insert R-3 in series with the armature. The applied armature voltage is reduced, and the doors attain slow closing speed as previously described.

The leading door edge is provided with a SAFETY EDGE contact which closes when the leading door edge strikes an obstruction. An OPEN button is provided in the car station for the purpose of reopening and holding open the doors.

The doors are reopened fully while closing at any speed if any one or more of the following devices is operated while the doors are closing: (1) the OPEN button is pressed, (2) the CAR CALL button corresponding to the floor at which the elevator has stopped is pressed, (3) the HALL CALL button corresponding to the set direction of travel for the car, is pressed at the fioor where the elevator has stopped, or (4) the SAFETY EDGE contact is actuated.

Pressing an appropriate CAR or HALL CALL button causes the CAR AND HALL CALL PICKUP contact to close momentarily, in turn causing relay UDC to close momentarily. The momentary closure of UDC-2 picks up relay DOX, FIG. 7, through DOL-2, RA-4 and DCL-3. The momentary closure of the SAFETY EDGE contact, or the OPEN button, picks up relay DOX through RA-4 and DCL-3. DOX seals in through DCL-3, RA-4, DOX-2 and DOL-2. DOX-1 closes to pick up DO through RA-l and/or LRA-l. DO-3 closes to pick up DE through LRA-2. Since the picking up of relay DE signals the door operator to open the doors, the doors open fully because DOX cannot dropout until the OPEN LIMIT opens to drop DOL to open DOL-2 to drop DOX to open DOX-1 to drop D0 to open DO-3 to dropout relay DE.

Upon reaching the fully open position, the doors immediately start to close if no device is being operated which is responsible to keep the doors open. The OPEN LIMIT switch opens to dropout O and DOL, the door open circuit. The doors stop opening when 0 drops out. DOL-2 opens to dropout DOX, FIG. 6. DOX-l and DOL-1 open to dropout DO. DO-3 opens to dropout DE. DE-l closes to pick up C, the door close circuit, which causes the doors to immediately start closing, as previously described.

The doors will remain fully open indefinitely as long as the OPEN button is pressed, the SAFETY EDGE contact is actuated, or the STOP switch is operated to its STOP position. Continuous pressure on the OPEN button or SAFETY EDGE contact causes relay DOX to pick up and remain picked up through RA-4 and DCL-3. DOX-l closes to pick up DO through RA-l and/or LRA-l. DO-3 closes to pick up DE through LRA-2. Operation of the STOP switch to its STOP position drops out SAF. SAF-Z closes to pick up DE through RA-2, DCL-l, and/or LRA-3. As long as relay DE remains picked up, the door remains fully open.

A momentary operation of STOP switch, FIG. 6, while the doors are closing will cause the doors to reverse and reopen only as long as the STOP switch is deactuated. The doors need not open fully should the STOP switch be returned to its actuated position before the doors have reached the fully open position. When the STOP switch is again actuated, the doors will reverse again and start closing.

A momentary operation of the STOP switch any time while the doors are opening as the car levels into a floor does not prevent a momentary interruption of the beam from causing the doors to start immediately closing as soon as the beam is reestablished. A momentary operation of the STOP switch when the doors have been fully closed for a short time (sufficient for delayed dropout relay TCDL to drop out after deenergization) with the car at rest at a landing will not cause the doors to open to their fully open position if the beam is broken before the doors fully open, for although DT is picked up by delayed TDCL-l, the breaking of the beam opens EE-l which drops out DT, causing DT-2 to close which picks up TDA which opens TDA-l to dropout D which opens DO-3 to let DE dropout.

The sequence of operation when the car is answering a hall call will now be given. Hall call relay HC, FIG. 7, is energized at this time, closing contact I'IC-I in the OX relay energizing circuit in FIG. 5, and opening contact PIC-2 in'the TDA and TDAT energizing circuit in FIG. 7.

With contact I-IC-2 now open, relay TDA can be energized only through the closing of the normally open latch timer contact TD, which is functional only in the event of a mechanical interlock failure. Since relay TDA cannot now pick up when the photobeam is broken during the door opening cycle, contact TDA-l, FIG. 6, cannot open to dropout relay DO. Relay DO remains picked up until the doors become fully open and contact DOLnl opens. Thus, the doors must always fully open.

With contact I-IC-l now closed, relay OX always becomes energized during the door opening movement while the doors are positioned between the EARLY OPEN SLOWDOWN and OPEN LIMIT switches, by the circuit through EARLY OPEN SLOWDOWN, OX relay coil, 0-5 and I-IC-I to Contact OX-l closes to connect resistors R-4 and R-S across the door motor armature so that the doors always open at creep speed during the last 6 inches of opening movement.

The control operation is modified when an abnormal condition, such as a burned-out lamp, smoke, or dirt, prevents the photocell 37 from receiving the light beam. It will be assumed that the elevator is stopped at a landing. First, relay EE, FIG. 5, drops out, the same as when an obstruction is in the path of the beam. Contact EE-Z closes to pick up relay EEX, FIG. 6. Contact EE-3 closes with no immediate effect. The doors close at the slow closing speed and, if further demands for service are registered by either a hall or call call, the elevator car will travel to another floor. As the elevator brake is energized and the car starts moving through the hoistway, the brake contact closes to pick up relay RA. RA-3 closes to pick up EEY through EE-3 and DCL-2. EEY seals in through EEY-l and DOL-2. EEY-2 closes to pick up DOX through TDA-2 and DOL-2. EEY-3 closes to pick up EEZ. As the elevator initiates its slowdown for the next stopping floor, relay S drops out. 8-1 closes to seal in EEZ through EEZ-2 and EE-4.

As the car levels into the next stopping floor, the doors open at normal opening speed as the car enters the door operating zone, slowing down during the last 6 inches if the car is answering a hall call as previously described. While the doors are opening, the car is completing its leveling operation and the brake contact has not yet opened to cause relay RA to drop out. Relay LRA, however, is picked up because the car leveling units, set for the door operating zone, have closed their contacts.

The doors now open to their fully open position as follows. Relay DO, FIG. 6, is sealed in through TDA-l, DOL-l and DO-2, while also being energized through LRA-l and DOX-l.

both through DT-2, PIC-2 and SWlb. TDA seals in and power is sustained on TDAT through TDA-3 and TDAT-1. TDA-2 opens but has no effect since DCL-3 is now closed. DOX remains picked up through DCL-3, EEY-2 and DOL-2. DO remains picked up through LRA-I and DOX-I. DE remains picked up through LRA-Z and DO-3. Until either the OPEN LIMIT opens or contact DE-2 opens, relay 0 remains picked up and applies opening direction power to the door motor 61. Since DE-2 remains closed, the doors must open to their fully open position.

Upon becoming fully open, OPEN LIMIT opens to dropout O and DOL. The doors stop under dynamic braking at their fully open position and immediately thereafter reclose at the medium closing speed, with no pause at the fully open position.

More particularly, when DOL drops out, FIG. 5, DOL-2 opens to cause EEY and DOX to drop out. EEX is still picked up through EE-2 because the photocell 37 is dark. EEZ is sealed in through EEZ-2, EE-4 and RA-5. DOX-l opens to dropout DO. DO-3 opens to dropout DE. DE-l closed to pick up C through CLOSE LIMIT. EEX-2 closes to pick up SDR. EEX-l closes, but since EEZ-l is open, resistor R-4 is disconnected from across the armature. SDR-2 opens to insert R-3 in series with the armature. SDR-l and C-3 close to connect R2 in parallel with the armature. C-4 opens to remove the dynamic braking short circuit through 0-3 from across the armature. C-1 and C-2 close to apply closing direction power'to the door motor through R-l, C-l, armature, R-3 and C-2.

Because resistor R4, FIG. 5, is not now connected across the armature, a smaller current is drawn through R-l than when the doors closed at slow speed. The corresponding voltage drop across R-l is less and the voltage across the armature is more than that available for the slow door closing speed. The voltage across the armature is not as great as for normal closing speed because resistor R-3 is now connected in series with the armature, whereas at normal closing speed R-3 is shorted by contact SDR-2. Therefore, the doors close at a medium closing speed between slow closing speed and normal closing speed.

When the failure which darkened the photocell is corrected, relay EE drops out, opening EE-4 to dropout EEZ, FIG. 7. If the car has stopped at a floor, relay EEY will have dropped out when the doors became fully open, due to the opening of contact DOL-2. Since EEZ cannot pick up again, until EEY-3 closes, which cannot occur until relay EEY again picks up y when the car is travelling through the hoistway with the doors fully closed and with the beam broken, contact EEZ-l remains closed to connect resistor R-4 across the armature any time thereafter the beam is interrupted. Therefore, normal operation is automatically restored whenever the failure is corrected while the car is stopped at a landing.

Should the PEC failure be corrected while the car is travelling through the hoistway, as could happen if smoke was responsible for the failure, the restored beam will cause relay EE to drop out. EEY, FIG. 7, will have been picked up through RA-3, EE-3, and DCL-2, and sealed in through EEY- l and DOL-2, before the fault was corrected. EEY-3 will be closed to keep EEZ picked up. Although contacts EE-3 and EE-4 open when the beam is restored, EEY and EEZ remain picked up. When the car next stops at a floor, normal operation is restored at the instant when the doors become fully open, because the OPEN LIMIT opens to dropout DOL, which causes DOL-2 to open which causes EEY to drop out, which opens contact EEY-3 to cause relay EEZ to drop out. When relay EEZ drops out, contact EEZ-l closes to connect resistor R4 across the armature through 0-6, EEX-l and 0-3 whenever the beam is subsequently interrupted, thus restoring normal operation.

The control operation is also modified when a door interlock mechanical failure prevents the hoistway door from being unlatched. As previously described, relay DO, FIG. 6, is picked up through UDC-I and sealed in through TDA-1, DOL-I and DO-2, when the elevator is conditioned to stop at the next floor for which a call is registered. As the car levels into the door operating zone, the CAR LEVELING UNIT switches, FIG. 6, close to pick up LRA. LRA-2 closes to pick up DE through DO-3. DE-2 closes to pick up and cause opening power to be applied to the door motor.

Should the mechanical door interlock fail to unlatch the hoistway door, opening direction power will be applied to the doors, but they will not be able to overcome the mechanically locked condition. Under such a circumstance, override circuit 68 removes the opening power and applies closing power so that the door may fully reclose to reestablish the electrical interlock contacts 32, allowing the elevator car to continue to service other floors.

More particularly, as the car stops, the BRAKE contact opens to dropout RA, FIG. 6. RA-6 closes to apply initiating power to latch timer TD through DCL-4 and DO-S. Upon the expiration of the latch timer interval, timer contact TD-l, FIG. 7, closes to pick up TDA and energize slow pick up relay TDAT. TDA seals in and TDAT remains energized through TDA-3 and TDAT-1.

Assuming that other conditions are normal (the beam is operative and devices are not operated which could effect the picking up of relay DOX), contact TDA-l opens to dropout DO, FIG. 6. DO-3 opens to dropout DE. DIE-2 opens to dropout O and remove opening direction power from the door motor. DE-l closes to pick up C, applying closing direction power to the door motor until the CLOSE LIMIT opens, which drops out C to remove closing power. This operation allows the door interlock contacts 32 to be reestablished, and the elevator may now proceed to travel to its next call.

Under conditions where relay DOX, FIG. 7, also would have been picked up when the doors could not open due to a mechanical failure to unlatch the hoistway doors, the same effect is produced by the following sequence of operations. Contact TDA-l opens, but relay DO remains picked up through the parallel combination of RA-l and LRA-l in series with DOX-1. TDA-2 opens to dropout DOX because DCL-3 is open. DOX-l opens to dropout DO. At this point, the sequence of operations is exactly the same as previously described above.

It will be apparent that the control is usable with a bank of elevator cars or with a single car. Similarly, changes can be made in other portions of the elevator control without affecting the functioning of the door control.

While an illustrative embodiment of the invention is shown in the drawings and will be described in detail herein, the invention is susceptible of embodiment in many different forms and it should be understood that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiment illustrated.

We claim:

1. In an elevator system including an elevator car with a doorway for passenger transfer, sensing means having a source of energy for projecting an energy field across said doorway,

and means responsive to a change in condition of said energy field for generating a passenger transfer signal, control apparatus comprising: means responsive to a condition which indicates no passenger is present in said doorway for generating both said checking signal and said transfer signal for generating an error signal to indicate that said sensing means is inoperative.

2. The control apparatus of claim 1 for an elevator system in which an elevator car is movable through a hoistway to serve a plurality of landings, said car having a door for opening and closing said doorway to passenger transfer, door motive means operative during one portion of an elevator cycle for opening 160 a checking signal; and means responsive to the presence of and closing said door across said passageway, car motive means operative during the remaining portion of said elevator cycle for starting, stopping and moving said car through said hoistway to serve said plurality of landings, said car motive means including contact means actuated during said remain- .ing portion of said elevator cycle, said no passenger condition responsive means including said contact means in series with a potential source for generating said checking signal when said contact means is actuated, whereby said condition which in- :dicates no passenger is present corresponds to said elevator car being in its starting, stopping and moving cycle.

3. The control apparatus of claim 2 wherein said error signal generating means includes an electrical path for energizing a self-holding memory, said memory generating said error signal ,when in an energized state, said electrical path including in series a first pair of contacts actuated by said transfer signal, and a second pair of contacts forming a portion of said contact means.

4. The control apparatus of claim 3 wherein said error signal generating means includes reevaluation means for dropping out said self-holding memory after each completion of an opening and closing movement of said car door, whereby said self-holding memory is again energized only if the pairs of contacts in said electrical path are actuated.

5. The control apparatus of claim 1 for an elevator system in which said elevator car has a movable door for opening and closing said doorway to passenger transfer, including door motive means for moving said door through an opening and closing cycle across said doorway, and means connected to said door motive means and responsive to said error signal for modifying the movement of said door during said cycle.

6. The control apparatus of claim 5 wherein said door motive means is responsive to the transfer signal from said sensing means for moving said door during the CIOSll'lg operation at a slow speed, and said door movement modifying means is responsive to said error signal to override said slow speed and cause said door to close at a speed greater than said slow speed.

7. The control apparatus of claim 6 wherein said door motive means moves said door through a closing operation at a fast speed substantially greater than said slow speed when no transfer signal from said sensing means is present, and said door movement modifying means overrides said door motive means to close said door at a speed intermediate between said slow speed and said fast speed when said error signal is present.

8. The control apparatus of claim 6 wherein said door motive means initially opens said door at a fast speed sufficient to expose the passageway to passenger transfer and thereafter intermediately opens said door at a speed materially slower than said fast speed, and said door movement modifying means is responsive to said error signal for overriding said materially slower speed and causing said door to open intermediately at said fast speed.

9. The control apparatus of claim 1 for an elevator system in which said elevator is movable through a hoistway to serve a plurality of landings, including reevaluation means for causing said error signal generating means to generate a new error signal each time the elevator car moves to a new landing.

10. The control apparatus of claim 9 for an elevator system in which said elevator car has a movable door for opening and closing said doorway to load transfer, including door motive means for moving said door through a first opening and closing cycle across said doorway when said sensing means is operative and through a second different opening and closing cycle across said passageway when said error signal is present, and said reevaluation means is effective when the sensing closing cycle.