US2589292A - Elevator - Google Patents

Description

D. SANTINI ELEVATOR 4 Sheets-Sheet l Filed Sept. 2, 1949 INVENTOR Danilo Santini. BY

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INVENTOR Danilo Sonrini.

4 Sheets-Sheet 2 D. SANTINI ELEVATOR March 18, 1952 AFiled sept. 2, 1949 V Fig.2A.

WITNESSES: 5.4222/ BY @f2/M2M@ ATTORNEY March 18, 1952 Filed Sept. 2. 1949 /Ll ARU D. sANTlNl ELEVATOR IDU 4 Sheets-Sheet 5 ACCI AL5 CCI BL5 CCCI CLS {DCCI DL5 DRES GER sAh Ll B3 SAQ AST 1 2 INVENTOR Danilo sommi. BYS

ATTORNEY D. SANTINI 2,589,292

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ATTO RN EY Patented Mar. 18, 1952 ELEVATOR Danilo Santini, Tenafly, N. J., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application September 2, 1949, Serial No. 113,845

v27 claims. (c1. 187-29) This invention relates to multi-car elevator systems, and it has particular relation to dispatchers for dispatching elevator cars at suitable intervals from a dispatching floor. f

Elevator dispatchers may be of the rotational or non-rotational type. A rotational dispatcher for a bank of elevator cars dispatches elevator cars from a dispatching floor in a predetermined invariable order. The order of arrival of cars at the dispatching floor has no eiect on the order in which the cars are dispatched inithe rotational dispatching system. A non-rotational dispatcher dispatches elevator cars from the dispatching floor substantially in the order of arrival of the cars at the dispatching floor. Although aspects of the invention may be employed in a rotational dispatcher, the invention is particularly suitable for the non-rotational dispatcher and will be discussed with respect to a non-rotational dispatcher.

The demand for elevator service is subject to substantial variation throughout the day. If the dispatching interval of an elevator dispatcher is selected for a predetermined service demand, any variation in the service demand may result in a bunching of the elevator cars at the dispatching or other floors and may result in poor service to intending passengers. I

In accordance with the invention, an elevator dispatcher has a dispatching interval which is selected for a predetermined service demand. For example, the interval may be selected to provide suitable service under conditions of a heavy demand for service from intending passengers. However, the dispatch of elevator cars from the dispatching oor is expedited under certain conditions.

Let it be assumed that the dispatching interval is selected for a heavy service demand and that it represents a comparatively long time value. As long as the heavy service demand continues, a car arrives at the dispatching floor as each preceding car at the dispatching floor is dispatched. Substantially only one car is present at the dispatching floor under these conditions.

If the demand for elevator service decreases, cars will tend to accumulate at the dispatching floor. However, in response to the accumulation of a predetermined number of cars at the dispatching floor, the dispatching interval for the next car to be dispatched is decreased from the aforesaid long value to a medium value of time. Following the dispatch of a car upon the expiration of a medium dispatching interval, succeeding cars again are dispatched in accordance with long dispatching intervals until the predetermined number of cars again accumulates at the dispatching floor.

In the event that a number of cars greater than the predetermined number accumulates at the dispatching floor, the dispatching system automatically decreases the dispatching interval of the next car to be dispatched to a short value of time. The secondV car to be dispatched is dispatched after the expiration of themedium interval of time measured from the departure of the first car. The third and succeeding cars thereafter are dispatched in accordance with the long dispatching intervals.

The variable sequence of dispatching provided by the invention prevents excessive accumulation of cars at the dispatching oor and minimizes the possibility of the bunching of cars at any point -in the system.

Preferably the next car to be dispatched from a dispatching floor is selected as promptly as possible after the arrival of the car at the dispatching iioor. This enables the car attendant to open his doors and load his car while awaiting the expiration of his dispatching interval. A suitable signal may be given to each attendant for the purpose of notifying him that his car has been selected as the next car to be dispatched from the dispatching floor. At the same time a suitable signal such as a floor lantern may be actuated at the dispatching floor for the purpose of notifying intending passengers that the car adjacent the floor lantern will be the next car to leave the dispatching iioor. Assuming that a car has been selected as the next car to leave the dispatching floor and that the dispatching interval for the car has expired, the car may be started in any suitable manner. For example a lamp may be illuminated in the car to indicate to the car attendant that he should start the car.

In some elevator installations the service demand in the two directions of travel of elevator cars may diler. For example the service demand for travel in the down direction may be substantially heavier than that for the up direction. In accordance with a further aspect of the invention, the dispatching intervals at either or both of the dispatching floors (usually the upper terminal floor and the lower terminal or street iloor) may be adjusted independently or simultaneously in accordance with the dif ference in the service demand for the two directions of travel. 'I'hus if the predominant demand is in the down direction, the cars may be dispatched with a shorter dispatching interval from the upper dispatching oor than that employed for the lower dispatching floor. If the predominant demand is in the up direction, the cars may be dispatched with shorter dispatching intervals from the lower dispatching floor.

Thus far the invention has been discussed with reference to a dispatching interval based -on the positioning of the cars adjacent the dispatching floor. The invention further contemplates the adjustment of the dispatching interval in accordance with the positioning of the cars with respect to localized service demand areas other than the dispatching floors. For example the noors served by the elevator cars may be divided into zones or localized service areas. A service or call demand in excess of a predetermined value from intending passengers in any zone with no car in position to answer the service demand within a reasonable time expedites the dispatch of a car from the dispatching floor for the purpose of answering with reasonable promptness the service demand.

If desired, the system may be so arranged that the accumulation of a predetermined number of cars, such as three carsV at a, dispatching door, immediately dispatches one of the cars from the dispatching floor. should a service demand from any zone occur when no car is in position to answer the service. demand within a reasonable period of time, a car is immediately dispatched.. from. the dispatching floor when only two cars accumulate at; such floor in order to aid in answering the service-demand.

A still heavier service demand such as a service demand above a predetermined valuey from two zones with no car in position to answer the service demand Within a reasonable time may further expedite the dispatch of a car from the dispatching' floor. Under these circumstances a car may be dispatched immediately from the dispatching floor, even if it is the only car at the i Y patching floor.

The above discussion has been primarily with reference tol service demand from the iioors served. by the elevator cars. The invention further contemplates expediting the dispatch of a car in response to a service demand aboveaprede'termined value from the passengers within the car. Thus if the. car attendant operates more than a predetermined number of car call buttons for the purpose of registering the floors to which his passengers desire to be carried while he is awaiting a start signal at one of the dispatching floors, his start signal may be expedited.

Itis, therefore, an object of the invention to provide an improved elevator dispatching system which is responsive to` service demand.

I t isl also an objectv of the invention to provide an elevator dispatching system wherein a plu-- rality of successive dispatching intervals may be varied' as a function of elevator cars accumulating at the dispatchingfloor.

It is an additional object of the invention to provide an elevator dispatching system wherein a carto be dispatched is selected promptly, and the dispatch of the car thereafter occurs after the expiration of a dispatching interval which is a function of the accumulation of elevator cars adjacent the dispatching door.

It is a further object of the invention to provide an elevator dispatching system wherein the dispatching interval varies as a function of the difference in service demand for the two directions of travel of the elevator cars.

Itis another object of the invention to provide an elevator dispatching system wherein the dispatching interval is varied as a function of the localized service demand and the position of the elevator cars with respect to the localized service demand,

It is a still further object of the invention to provide an elevator system including an elevator dispatcher having a dispatching interval which varies as a function of service demand from passengers within the elevator cars.

IOther objects of the invention will be apparent from the following description, taken in conjunction with the accompanying drawings, in which:

Figure l is a view in front elevation with parts broken away of an elevator system.

Fig. 2 is a schematic view in straight line form of an elevator dispatcher embodying the invention.

Fig. 2A is a schematic view of the relays employed in the system of Fig. 2. If Figs. 2 andv 2A are placed in horizontal alignment, it will be found that the windings and contacts of the Various relays are in horizontal alignment.

Fig. 3 is a schematic view of an adjustable resistor which is responsive to the difference in service demand for the two directions of travel of elevator cars.

Fig. 4 is a schematic view in straight line form showing additional circuits which may be employed in the elevator dispatching system.

Fig. 4A is a schematic view of the relays illustrated in Fig. 4. The windings and contacts of the relays of Figs.v 4 and 4A may be brought.

into horizontal alignment in the manner dis-V cussed with reference to Figs. 2 and 2A, and

Fig. 5 is a schematic view of a typical floor call circuit.

The invention iS applicable to banks of elevator cars containing various numbers of elevator cars. For theY purpose of discussion, a system will be described with reference to a bank containing four elevator cars, but it is to be understood that it may be employed with banks having diiferent numbers of elevator cars. The cars will be designated by the letters A,VL B, C and D, and components specific. to the respective cars will be designated by the letter, A, B, C or D, followed loyV other suitable designating characters.

Relays are employed which may have make" or break contacts. Make contacts of a relay interrupt a circuit as long as the relay is deenergized. Energization of the relay closes to make contacts. The break contacts of a relay are closed to complete an electrical circuit as long as the relay is deenergized. Energization of the relay opens its break contactsto interrupt a` circuit. The various contacts of a relay are each identified by the reference character applied to the relay followed by a reference character specific to each set of contacts.

The relays specific to the car A are as follows:

AU-Upper terminal relay AL-Lower terminal relay AN-Next relay AS-Auxiliary start relay ACC- Car call expediter The following relays are common to all cars:

Is, 2s, as, K, IDU and IDL- Interval relays 2E and 3E-Expediter relays T, UT and LT-Auxiliary expediter relays US and LS-Start relays R0, RI, R2 and RS-Service demand relays PI, P2 and P3-Car position relays 2DR to IGKDR-Floor down-call registering relays IUR to SUR-Floor up-call registering relays FIGURE 1 In Fig. 1 car A is secured to a counterweight I through one or more iexible ropes or cables 3. The rope or ropes pass over a sheave 5 which is mounted on the shaft I of an electric motor 9. Brake mechanism I I is provided for stopping the elevator car and for holding it in any desired position.

The motor 9 may be energized in any conventional manner for the purpose of moving the elevator car A in either of its two direc'tionsof travel between its terminal oors. It will be assumed that the elevator car is controlled by a car switch I3 which is closed to initiate movement of a car. After the car has started in movement, the car stops automatically at oors for which push buttons in the car, or push buttons for the various iloors, have been :actuated It will be understood that the push-button station I5 for the car has one push button" for each of the oors served by the elevator car. The elevator attendant actuates one of the push buttons for each of the iloors at which the ele- Vator car is to stop for the purpose of discharglng passengers. Two floor push-button stations IIl and I9 are illustrated. The station I'I lis located at the second floor and contains an up push button 2U and a down push button 2D. Similarly the station I9 is positioned at the third floor and has a down push button 3D and an up push button 3U. In accordance with common practice, each of the iloor push-button stations is common to the entire bank of elevator cars.

Inasmuch as the mechanism for controlling the starting and stopping of the elevator carlis well known in the art, a detailed description of such apparatus is believed to be unnecessary. Such apparatus may include a selector 2i which is responsive to the position of the car. For example the selector includes a stationary panel 23 of insulating material which carries several rows of contact segments. Two rows Aa and Ab are illustrated in Fig. l. One of the contact seg ments in each of these rows is provided for each riage 25 has a separate brush 3l or 33 for engaging successively the contact segments of leach of the rows of segments.

In addition the selector may have additional contact segments for other control purposes. For example the panel 23 has a contact segment Ac which is engaged by a brush 35 on the movable carriage when the elevator Acar is at or adjacent to its upper terminal position'.Y The panel 23 has an additional contact segment Ad which is engaged by a brush 31 when the elevator car is at or adjacent to its lower terminal floor. In Fig. 1 the carriage 25 is located below the lower terminal floorY at aA position which may correspond to the basement of a building served by the elevatorcar. l

6 ,FIGURE 2 When a number of elevator cars are associated in a bank it is desirable that they be dispatched from one or more dispatching floors according to suitable schedules. In most installations of banks of elevator cars, the dispatching iioors usually are the upper terminal iloor and the first oor of the building served by the bank. It may be assumedthat if the building has a basement, a special operation is necessary to move the elevator car below the rst floor or dispatching iioor to the basement. For the purpose of the present discussion it will be assumed that the elevator cars operate between the rst floor which comprises the lower terminal or dispatching floor and the highest floor which serves as the upper terminal or dispatching floor.

It will be understood that similar dispatching equipment may be provided for each of the dispatching oors. With reference to Fig. 2, it will suffice to describe in detail the dispatching equipment associated with the upper dispatching oor.

As cars reach the dispatching floor, it is desirable that the next car to be dispatched from the floor `be selected as promptly as possible. This enables the car attendant to ll his car as he waits for the expirationof his dispatching interval. The selection of the next car to be dispatched is erectedby selecting mechanism which is operated in part by a constant speed motor 39. This motor is releasably coupled to a cam 4I by means of an electromagnetic clutch RC. When the winding of the clutch RC is deenergized, the motor 39 is disconnected from the cam 4I. When the winding is energized, the motor is connected to the cam 4I and rotates the cam for the purpose of selecting the next car to be dispatched from the dispatching oor.

Energization of the electromagnetic clutch RC is Vcontrolled. in part by upper terminal relays AU, BU, CU and DU. For example when the elevator car A is at or adjacent its upper termi-` nal, the brush 35 engages the contact segment Ac to connect the winding of the upper terminal relay AU across the buses LI and L2 which represent a source of direct current. When the upperterminal relay AU is energized, it closes its make contacts AUI and AU2. In closing, the contacts AU2 prepare the winding of the next relay AN for subsequent energization.

Closure of the make contacts AUI completes an energizing circuit for the electromagnetic clutch RC as follows:

LI, AUI, RC, ANI, BNI, CNI, DNI, L2

If some car of the bank has already been designated as the next car to leave the dispatching floor, one of the sets of the break contacts ANI, BNI, CNI or DNI will be open to prevent energization of the electromagnetic clutch RC. It will be assumed, however, that no car has been so designated and that the electromagnetic clutch RC is energized upon arrival of the car A at the upper dispatching cor.

As the cam 4I rotates, it closes successively the switches AY, BY, CY and DY. This continues until'the cam closes the switch of a car located at or adjacent the dispatching iloor. Thus when the cam closes the switch AY, a circuit is completed for the next relay AN:

Ll, AUZ, AN, ASG, AY, L2

Had any of the other switches BY, CY or DY been closed, the associated next relays BN, CN,

DN would have remainedA deenergized for the reason that the cars YB, C and D are assumed to be away from the upper dispatching oor, and the contacts BU2, CU2 and DU2 are open.

When the next relay AN is energized, it opens its break contacts ANI and closes its make contacts ANZ and ANS. The opening of the break contacts ANI deenergizes the winding of the electromagnetic clutch RC, andA the earn 4| consequently stops rotating.Y The selecting mechi anism` cannot be operated again until the break contacts ANI have Vbeen reclosed. v

"In closing, the contacts ANZ prepare the relay AS for subsequent energizatin.

Closure of the make contacts AN3 completes the selection of the car A as the next car to be dispatched. The closure may be employed in variousr` ways for completing the selection. In the. specific embodiment herein illustrated,

closureV of the contacts .AN2 illuminates a next signal lamp ANL through the circuit:

LI, ANS, AS`2, AHL, ANL, L2

The next signal lamp ANL is located on the car A and informs the attendant that his car has been selected as the next car to leave the dispatching floor. Consequently the car attendant can proceed to load his car. It should be noted that this selection is effected rapidly.

"Closure of the next relay can be employed forv other functions. For example such 'closure mai7 be employed for illuminating hall lanterns at the dispatching floor to indicate to intending pas-` the system herein discussed the dispatching system may be said to start a car by notifying the car attendant that he should leave the dispatching floor. To this end the motor 39 is releasably coupled to a timer cam i3 through an electromagnetic clutch SC. The winding of this clutch is Venergized through the circuit:

LI,AISi,v SC, ASI, BSI, CSI. DSI, L2

Wheng the winding is energized, the cam 133 is actuated away from a starting position to operate a cam-operated switch S. When the electro# magnetic clutch is deenergized, a spring i5 re turnsthe cam 43 to its 'starting position. The construction of the motor 39 and the electromagnetic clutches may be similar to that illustrat'ed in the Eames Patent 2.121.587. i

Each of the contacts ASI, BSI, CSI and DSI opens when its associated car is ordered to start from the dispatching door. Until contacts ASI,

BS, CSS and DSE are all closed, the electromagp netic clutch cannot be energized and a succeeding timing interval cannot'be initiated.

When the timing cam I3 reaches the switch S, the switch contacts close to energize the interval relay iS through the circuit:

Li, IS, S, ASI, BSI, CSI, DSI, L2

'.ilie interval relay iS opens its break contacts IS! and IS, and closes its make contacts IS2 and ISS. The contacts ISZ establish a holding circuit around the switch S. The contacts ISI in opening deenergize the winding of the electroff magnetic clutch SC, and the spring 45 promptly restores the timing cam to Aits starting position. The contacts IS3 control in part the energization of the expediter relays 2E and 3E. The contacts ISA in opening deenergize the interval relay 2S. Thisv relay has a time delay in dropout which isldetermined in any suitable manner as by a resistor 41 which is connected across the winding of the relay 2S. The resistance value of the resistor A'I may be adjustable to permit adjustinent of the dropout time of the interval relay V2S. l

It will be understood that the interval relay 2S normally is energized. When the contacts I`S4 open and interval relay 2S times out, it opens its make contacts 2SI and closes its break contacts 282. Closure of the break contacts 2S2 has no effect on `the operation of the system as long as the expediter relay 2E remains deenergi'zed and contacts 2EI remain open.

Opening of the contacts 2SI deenergizes the normally-energized interval relay 3S; The relay 3S also has a time delay in dropout. The time delay may be obtained in any suitable manner as by means of a resistor 49 which is connected across the winding of the time interval relay 3S.

Upon the expiration of the time delay of the relay 3S, it drops out to close its break contacts SSI. This completes' the following circuit for the start relay US:

LI, SSI, US, L2

LI, AUZ, AS, AN2, USI, L2

to energize the auxiliary start relay AS.

When the start relay AS is energized, it opens its break contacts ASI, AS2y and AS4, and closes its make contacts AS3 and A55. 'The opening of the contacts ASI interrupts the energizing cir'- cuit for the` relay IS and prevents further energization of the relay IS or of the electromagnetic clutch SC until the car A has departed from the dispatching noor.

Opening oi the contacts AS2 extinguishes the next lamp ANL in the car A (and the hall lantern AHL). Closure of the contacts ASS starts the car A in any suitable manner. In the embodiment of Fig. 2, closure of the contacts AS3 illuminates the start lamp ASL which is located in the car A. This notifies .the car attendant that he should start away from the dispatching floor.

Opening of the contacts ASA deenergizes the' next relay AN. Contacts AN I reclose to `permit selection of another next car. Contacts ANZ open, but a holding circuit around these contacts maintained by the contacts ASE. Contacts ANS open to prevent 'premature reenergization the hall lantern and next signal. Y

As the car A leaves the dispatchingioor, :the contact 35 is moved out of engagementwith the contact segment Ac.

Consequently, the upper terminal relay AU is deenergized. Contacts AUI open to maintain the winding of the electromagnetic clutch RC deenergized until another car is at or adjacent the upper dispatching floor. Contacts AU2 open to deenergize the auxiliary start relay AS. Contacts AU3 open to decrease the possible energization of the expediter relays 2E and 3E.

'Ihe auxiliary start relay AS on being deenergized closes its contacts ASI to permit subsequent energization of the electromagnetic clutch SC. Contacts AS2 close to prepare the next signal lamp ANL for subsequent energization, and contacts AS3 open to extinguish the starting lamp ASL. Also contacts AS4 close to prepare the relay AN for subsequent energization and contacts AS5 open. If a dispatching interval expires before a car reaches the dispatching floor, the start relay US remains energized. As soon as a car reaches the dispatching floor, the car is promptly selected for dispatching and one of the next relay contacts AN2, BN2, CN2 or DN2 closes to energize the appropriate auxiliary start relay. Consequently, the rst car to reach the dispatching floor is promptly dispatched.

In the preferred embodiment of the invention, the dispatching interval which is the sum of the intervals determined by the switch S, and the interval relays 2S and 3S is set for a heavy service demand. As long as the service demand continues, a car reaches the dispatching iloor as another car leaves the dispatching floor to pro- ,vide eflicient system operation.

Should the service demand momentarily decrease, cars may tend to accumulate at the dispatching floor. Efficient operation under these conditions is assured by the expediter relays 2E and 3E.

The current supplied to the expediter relays 2E and 3E is dependent on thenumber of cars at or adjacent the dispatching iloor. For example, if the car A is adjacent the dispatching door, its brush 35 engages the contact segment Ac to energize the upper terminal relay AU. If the relay IS is energized at the same time, a circuit is established for the expediter relays as follows:

LI. AU3, AR, 5I, IS3, 2E and 3E in parallel, L2 A manually operable switch 5I may be included in this circuit to render the circuit ineffective or effective as desired.

The expediter relays 2E and 3E are designed to require a certain minimum current before they can pick up. The expediter relays may be of similar construction, but the relay 3E has in series therewith a resistor ER which restricts the current through the relay 3E to a value lower than that, traversing the relay 2E. The resistor AR further restricts the current supplied to both of the expediter relays.

The parameters of the circuit are so selected that the relays 2E and 3E pick up when different numbers of elevator cars are adjacent the dispatching iloor. As a specific example, the relay 3E may pick up when at least three elevator cars are adjacent the dispatching floor, whereas the relay 2E picks up when only two elevator cars are adjacent the dispatching floor. It will be understood, however, that the numbe-r of elevator cars to which the relays 2Ev and 3E respond may be selected in accordance with the requirements-of each elevator` installation.

The expediter relays 2E and 3E control the effectiveness of the relays 2S and 3S in delaying 10 energization of the start relay US. For example, ifthe expediter relay 2E is energized by the presence of two cars adjacent the dispatching door, the contacts 2EI close. Consequently as soon as the interval relay 2S drops out, the following energizing circuit is established for the start relay:

LI, zsz, zal, Us, L2

LI, SEI, Us, L2

Therefore a car is dispatched from the dispatch#- ing vfloor before the interval relays 2S and 3S drop out.

If the start relay US must await the timing out of the switch S and the interval relays 2S and 3S, a long dispatching interval results. If the start relay US is energized after the switch S and the interval relay 2S have timed out, a medium dispatching interval results. Finally if the start relay US is energized after the switch S alone times out, a short dispatching interval results.

The eect cf the expediter relays then is to decrease the accumulation or bunching of cars at the dispatching iioor. Inasmuch as the expediter relays never dispatch two cars simultaneously, there is no tendency for the cars to bunch after leaving the dispatching floor. In this way optimum service is rendered intending passengers of the elevator system under all conditions of service demand. f

Fig. 2 also shows lower terminal relays AL, BL, CL and DL which are associated with the lower terminal in the same manner by which the relays AU, BU, CU and DU are associated with the upper terminal. If desired a dispatching system may be provided for the lower terminal or lower dispatching floor which is similar` `to that described for the upper dispatching floor.

- Operation of Fig, 2-No car at upper terminal Consequently, the cam 43 is rotating for the purpose of closing the switch S. i

After the expiration of a predetermined interval the cam 43 closes the switch S to complete the following energizing circuit for the relay IS:

The relay IS consequentiy opens its break contacts ISI and I S4, and closes its make contacts s2 and Iss.

On closing, the contacts I S2 establish a hold-l ing circuit for the relay IS around the switch S. The opening of the contacts ISI deenergizes the winding of the eiectromagnetic clutch SC. The contacts ISS in closing prepare thelexpediter relays 2E l and 3E for subsequent energization. Opening of the contacts IS4 interrupts the energizing circuit for the interval relay 2S and this relay begins to time out. It will be recalled that the relays 2S and 3S have a delayed dropout.

At this point it is assumed that the car A reaches the upper terminal or dispatching iloor. As a result of the engagement of the contact segment Ac` by the brush 35 of the selector, the upper terminal relay AU is energized. This relay closes its rmake contacts AUI, AU2 and AU3. The contacts AU3 in closing complete the following energizing circuit for the expediter relays:

LI, AU3, AR, 5I, ISS, relays 2E and 3E in parallel, L2 l l In addition, the circuit for the expediter relay 3E includes the resistor ER. It will be recalled that the energization of the expediter relays through only one of` the sets of contacts AU3 to e DU3 is insuiicient for these relays to pick up.

In closing, the contacts AUI establish the iollowing energizing circuit for the winding of the electromagnetic clutch RC:

LI, AUI, RC, ANI, BNI, CNI, DNI, L2

Consequently the cam 4I starts to rotate and successively closes the switches associated therewith until the switch AY is closed. Closure 01' the switch AY establishes the following energizlng circuit for the next relay AN:

LI, AUZ, AN, ASA, AY, L2

As a result of its energization, the next relay AN opens its break contacts ANI and closes its Vmake contacts ANZ and AN3. Opening of the contacts ANI interrupts the energizing circuit for the winding of the electromagnetic clutch RC andv the cam 4I consequently discontinues its rotation. Closure of the contacts AN2 prepares the auxiliary start relay AS for subsequent energization. Finally closure of the contacts AN3 establishes the following energizing circuit for the next lamp and hall lantern of the car A:

Ll AN3, A82, AHL, ANL, L2

Consequently the attendant of the elevator car A is notied promptly that his car will be the next car to leave the upper dispatching floor, and he begins loading his car.

Upon the expiration of its dropout interval, the relay 2S drops out to open its make contacts ZSI and to close its break contacts 2S2. Opening of the contacts 2SI interrupts the energizing circuit for the interval relay 3S, and this relay begins to time out. The delay in dropout of the intein/al relay 3S is determined by the resistor 49.. Closure of the contacts 2S2 partially completes an energizing circuit for the start relay US. This energizing circuit is ineffective; however, unless the contacts 2EI of the expediter the following energizing circuit for the auxiliary start relay AS:

Ll, AUz, As,`.n\i2, Usl, L2

The `auxiliary start relay AS opens its break contacts ASI, ASZ and AS4 and closes its make contacts AS3 and ASS.

In opening, the contacts ASI deenergize the relay IS. This relay recloses its break contacts ISI? and IS4, and opens its make contacts IS2 and' ISS. Closure of the contacts ISI prepares the winding of the electromagnetic relay SC` for subsequent energization, but such energization cannot occur until reclosure of the contacts ASI. In opening, the contacts IS2 terminate the holding circuit around the switch S. Opening of the contacts IS3 prevents energization of the expediter relays 2E and 3E. Finally closure of the contacts I S4 re-establishes the energizing circuit for the interval relay 2S.

The interval relay 2S upon energization thereof closes its contacts 2S I to re-energize the interval relay 3S and opens its break contacts 2S2 to prevent energization therethrough of the start relay US. Upon energizationrthe interval relay 3S opens its lbreak contacts BSI to prevent energization therethrough of the start relay US.

Referring again to the auxiliary start relay AS, it should .be noted that upon energization this relay opens its break contacts ASZ forv the purpose of extinguishing the hall lantern AHL and the next lamp ANL. Also contacts AS3 complete an energizing circuit for the start lamp ASL which notices the car attendant that ne should start from the dispatching iloor. Contacts ASA open to deenergize the next relay AN and contacts AS5 establish a holding circuit around the contacts ANZ.

Since the next relay AN is deenergized, it closes the. contacts ANI topermit selection of another next car as promptly as possible. Also it opens the contacts ANZ, but these are by-passed by the holding contacts ASE. Opening of the'contacts AN3 has on immediate efect on the system.

When the car A leaves the upper dispatching oor, the brush 35 of the selector leaves the associated contact segment Ac to deenergize the upper terminal relay AU. The relay AU thereupon opens its make contacts AUI, AUZ and AU3. The opening of the contacts AUI requires arrival of at least one other car at the upper dispatching oor before the winding of the electromagnetic clutch RC can again be energized. Opening of the contacts AUZ deenergizes the relay AS. Opening of the contacts AU3 terminates any energization of the eXpediter relays 2E and 3E on behalf of the car A.

Upon deenergizatiom the relay AS closes its contacts ASI to permit another car to be started. Contacts AS2 and AS4 close, but have no immediate eiect on system operation. Also the contacts AS3 open to extinguish the start lamp ASL, and the contacts AS5 open.

Consequently, if a car arrives at the upper dispatching floor when no other elevator car is present at such door, the arriving car cannot be dispatched until at least a predetermined interval, which will be called a long interval, has expired, measured from the dispatch of the preceding elevator car from the upper dispatching floor. The predetermined interval is the sum of the intervals required for closure of the switch S and dropout of the relays 2S and 3S.

Car A at upper dispatching floor when subsequent car arrives 13 mediately after the interval relay 2S drops out.

The condition of the system immediately prior to the arrival of car B at the upper dispatching floor may be ascertained by reference to the preceding discussion. When car B arrives, the relays IS, AU and AN are energized. The windings of the electromagnetic clutches are deenergized and the switch S is open. The interval relay 2S has just dropped out to interrupt the energization of the interval relay 3S and the interval relay 3S now starts to time out. The expediter relays 2E and 3E are partially energized through the resistor AR, but the magnitude of the energization is insufhcient for either of the expediter relays to pick up.

Upon arrival of the car B at the upper dispatching loor, the brush B35 of its selector engages the associated contact segment Bc to complete an energizing circuit for the upper terminal relay BU. The relay BU closes its make contacts BUI, BU2 and BU3. Closure of the contacts BUI has no immediate effect on the operation or the system for the reason that the contacts ANI of the next relay AN are open. Closure of the contacts BU2 has no immediate effect on the operation of the system for the reason that the switch BY and contacts BN2 are open.

Closure of the contacts BU3 increases the energization of vthe expediter relays 2E and 3E.

These relays now are energized through the resistors AR and BR. in parallel. Such energization is insuicient to pick up the expediter relay 3E but sufces to pick up the relay 2E. Consequently the expediter relay 42E picks up to close its make contacts 2EI.

Inasmuch as the contacts 2S2 are closed as a result of the previous dropout of the interval relay 2S, the closure of the contacts 2EI completes a circuitfor the start relay US. The start relay closes its make contacts USI to complete the following energizing circuit for the start relay AS:

LI, AU2, AS, ANZ, USI, L2

Energization of the start relay AS starts the car A in the manner previously described.

It should be noted that the car A is started before the interval relay 3S drops out. Consequently the car A may be said to have been dispatched upon the expiration of a medium interval measured from the dispatch of the immediately preceding car from the upper dispatching oor.

When the car A leaves the dispatching oor, the associated brush 35 leaves contact segment Ac to deenergize the upper terminal relay AU. The contacts AUI open but have no immediate effect upon the operation of the system. The contacts AU2 open to deenergize the start relay AS. The contacts AUS reopen to prevent energization of the' expediter relays through the resistor AR.

It will be lrecalled that the next relay AN is 14 The next relay BN opens its contacts BNI to deenergize the winding of the electromagnetic clutch RCv and prevent further rotation of the cam 4i. The contacts BN2 close to prepare the auxiliary' start relay BS for subsequent energizaf tion. The contacts BN3 close to energize the next lamp BNL and the associated hall lantern. This noties the car attendant that car B is the next car to be dispatched from the upper dispatching floor and the car attendant starts to load his car.

The opening of the contacts ANZ and AN3 o: the next relay AN as a result of the energization of the auxiliary start relay AS has no immediate eiect on the operation of the system.

When the car A received its start signal, it will be recalled that the auxiliary start relay AS was energized to open its contacts ASI thereby deenergizing the relay IS. The relay IS closed its break contacts ISI to prepare the winding of the electromagnetic clutch SC for subsequent energization. Also the contacts IS2 opened the holding circuit around the switch Sl The contacts !S3 opened to deenergize the expediter relays ZE and 3E. The contacts IS4 closed to energize the interval relay 2S, and this in turn closed its make cont-acts 2SI to reenergize the interval relay 3S. The interval relays 2S and 3S when reenergized open their break contacts 2S2 and 3SI.

`Deenergization of the expediter relay 2E resulted in reopening of the contacts 2EI.

Upon departure of the car A from the upper ldispatching floor and the consequent deenergization of the auxiliary start relay AS, the contacts ASI close to establish the following energizing circuit for the winding of the electromagnetic clutch SC:

The relay IS opens its break contacts ISI to deenergize the winding of the electromagnetic 'clutch SC and closes its front contacts |S2 to establish a holding circuit around the switch S. The spring 45 resets the cam 43 following the deenergization of the clutch winding.

The contacts ISS close to energize the expediter relays 2E and 3E through the resistor BR. Howl ever, such energization is insuicient to cause deenergized in response to energization of the..

relay AS. Upon deenergization the next relay AN closes its contacts ANI to complete an energizing circuit for the winding of the electromagnetic relay RC as follows:

LI, BUI, RC, ANI, BNI, CNI, DNI, L2

The electromagnetic clutch consequently con- 'f7- LI, BU2, BN, BS4, BY, L2

either of .the expediter relays to pick up. The opening of the contacts IS4 interrupts the energization of the interval relay 2S and the interval relay starts to time out.

Upon expiration of the dropout time of the relay 2S, the contacts 2SI open to interrupt the energization of the interval relay 3S and this relay promptly starts to time out. In addition the contacts 2S2 close, but have no immediate effect on the operation of the system for the reason that the contacts 2EI are open.

Upon expiration of the dropout time of the relay 3S, contacts 3SI close to energize the start relay US. The start relay closes its contacts USI to complete the following circuit for the start relay BS:

LI, BU2, BS, BNZ, USI, L2

The auxiliary start relay BS opens its vbreak contacts BSI to deenergze the relay IS. Con- 'lamp BSI.

15 start 'lamp BSL. This notifies the car attendant that he should start car B away from the upper dispatching floor. Contacts BSSl open to deenergize the next relay BN. The contacts BSS are closed to establish a holding circuit across the contacts BNZ and USI.

The deenergization of the relay IS results in .reclosure f the contacts ISI and opening of the contacts IS2. These contact changes have no immediate efect upon the operation of the system. Contacts ISS open to deenergizethe expediter relay 2E and 3E; Contacts !S close to reenergize the interval relay 2S. The interval relay 2S closes its contacts ESI to reenergize the interval relay 3S and open its contacts 2S2. The

opening of the contacts 2S2 has no immediate eiiect on the operation of the system.

Energization oi the interval relay 3S opens contacts SSI to prevent further energization of the start relay US therethrough.

The next relay BN closes its contacts-BNI to Iprepare the circuit of the winding of the electra magnetic clutch RC for subsequent energization. Contacts BNZ open but have no immediate effect on the operation of the system. Contacts BNS open but have no immediate effect on the operation of the system.

As the car B leaves the upper dispatching floor, its brush B35 leaves the associated contact segment Bc. upper terminal relay BU results in deenergization of the auxiliary start relay BS.`

The auxiliary start relay BS upon deenergization closes its contacts BSI to complete an energizing circuit for the winding of the electromagnetic clutch SC. This starts the measurement of a new dispatching interval for the next elevator car to arrive after the dispatch of the elevator car B. The contacts BSZ close but have no irnmediate effect on the operation of this system. The contacts BSS open to extinguish the start The closure of the contacts BSc and the opening of the contacts BS5 have no immediate efect on the operation of the system.

From a consideration of this phase of the op- ,l

eration of a system in Fig. 2 it is clear that if an elevator car, such as the car A, is present at the dispatching floor at the time a. second elevator car, such as the car B, arrives, the dispatch of the car A is expedited. The car A leaves the .Y

dispatch oor upon the expiration of an interval which may be termed a medium interval. However, the long dispatching interval still must expire following the dispatch of the car A before the car B is dispatched from the dispatching floor.

It should be noted that the medium interval need not be a definite or fixed interval. The magnitude of the medium interval depends to some extent on the particular instant during the interval at which the second car B arrives at the dispatching fioor. The medium interval may have avalue between the time required for dropout of the relay 2S and the time required for dropout of the interval relay 3S as determined by the arrival of the car B. Consequently, if the car B arrives prior to the expiration of the dispatching interval for the car A, the dispatch of the car A is expedited.

Three cars arrive at dispatching floor simultaneously Next it is assumed that three cars A, B and C arrive substantially simultaneously at the` up- The resulting deenergization of the :'i;

16 per dispatching floor. At the time of arrival of the cars, the winding ofA the electromagnetic clutch SC is energized, and the cam 43 is rotating to close the switch S. The interval relays 2S and 3S are energized.

When the cars arrive at the upper dispatching floor the contact segments Ac, Bc, Cc are engaged respectively by their brushes to energize the upper terminal relays AU, BU and CU. These relays close their make contacts AUI, BUI and CUI, AU2, BU2 and CU2, and AU3, BU3 and CU3. Closure of the contacts AUI, BUI and CUI completes an energizing circuit for the winding of the electromagnetic clutch RC. Consequently the motor 39 rotates the cam 4I until one of theassociated switches for the cars A, Band C is closed. It will be assumed that the first of the switches to be closed is the switch AY. Closure of the switch AY completes the followingvcircuit for the next relay AN z Ll, Av2, AN, Asa, AY, L2

The next relay AN opens its contacts ANI to deenergize the winding of the electromagnetic clutchl RC. This permits only one of the cars to be selectedy as the next car.

The next relay AN also closes its contacts ANZ, but this has no immediate effect on the operation of the system. Closure of the contacts AN3 completes an energizing circuit for the next lamp, ANL and the associated hall lantern. This notifies the car attendant that the car A has been selected as the next car to leave the dispatching floor and he starts to load his car.

The closures of the contacts AU3, BU3 and CU3 Vhave no immediate effect on the operation of the system.

When the cam 43 closes the switch S, an energizing circuit is established for the relay IS through the circuit:

LI, LS, S, ASI, BSI, CSI, DSI, L2

Thevrelay IS opens its break contacts ISI and IS4, and closes its make contacts ISZ and IS3. 'Ihe contacts ISZ establish a holding circuit around the switch S and the opening of the contacts ISI prevents further energization of the Winding of the electromagnetic clutch SC. The spring 5 resets the cam 43 to its starting position.

The relay IS closes its contacts IS3 to energize the expediter relays 2E and 3E` through the resistors AR, BR; and CR in parallel. These resistors supply suiiicient current to pick up both of the expediter relays 2E and 3E. The expediter relay 3E closes its contacts SEI to complete an energizing circuit for the start re.- la-y US. The startrelay closes its contacts USI to complete the following circuit for the auxiliary start relay AS:

LI, AUZ, AS, ANZ, USI, L2

The auxiliary start relay AS opens its contacts ASI to deenergize the relays IS and AN. The contacts AS2 open to extinguish the next lamp ANL and the hall lantern for the elevator car A. In addition, the relay AS opens its contacts AS4 to deenergize the next relay AN. Contacts AS5 close to establish a. holding circuit around the` contacts ANZ and USI.

The contacts AS3 close to illuminate the start lamp ASL for the car A. Consequently the car attendant for the car A closes his car doors and starts his elevator car away from the dispatching floor. It should be noted that the minimum interval required under these conditions to dispatch the car A is that required for the cam 43 to close the switch S.

The deenergization of the relay IS closes contacts ISI to prepare the winding of the electromagnetic clutch SC for subsequent energization. The holding contacts IS2 are opened and the contacts IS3 are opened to interrupt the energization of the expediter relays 2E and 3E. The contacts IS4 close to reenergize the interval relay 2S. This reenergization takes place before the interval relay 2S has had an opportunity to drop out.

Because of its deenergization, the next relay AN closes its contacts ANI to complete an energizing circuit for the Winding of the electromagnetic clutch RC. (It will be recalled that the contacts BUI and CUI still are closed.) Consequently, the cam 4I is rotated by the motor 39 until either ofthe switches BY or CY is closed. It will be assumed that the switch BY is closed by operation of the cam 4I. Closure of the switch BY completes a circuit for the next relay BN as follows:

Ll, BU2, BN, Bst, BY, L2

The next relay BN opens its break contacts BNI to deenergize the winding of the electromagnetic clutch RC. This stops rotation of the cam 4I. The next relay closes its make contacts BN2, but this has no immediate effect on the operation of the system. Contacts BN3 close to energize the next lamp BNL and the associated hall lantern. This indicates to the car attendant that the car B has been selected as the next car to be dispatched from the dispatching noor. The car attendant consequently starts to load his car.

When the car A leaves the dispatching floor, the brush 35 of its selector leaves the associated contact segment Ac to deenergize the upper terminal relay AU. The resulting opening of the contacts AUI has no immediate eiect on the operation of the system. The contacts AUZ open to deenergize auxiliary start relay AS. The contacts AU3 open, but such opening has no immediate eiect on the operation of the system.

The departure of car A accompanied by the closure of contacts ASI has resulted in the energization of the winding of the electromagnetic clutch SC to effect rotation of the cam 43. Consequently the dispatcher interval for the car B is measured, from the departure of the car A, from the dispatching floor.

The cam 43 rotates until it closes the switch S to energize the relay IS. The relay IS closes its contacts IS2 to establish a holding circuit around the switch S and opens its contacts ISI to deenergize the winding of the electromagnetic clutch SC. Contacts IS4 open to interrupt the energization of the interval relay 2S, `and this relay starts to time out.

Contacts IS3 close to connect the expediter relays 2E and 3E for energization through the resistors BR and CR. in parallel. (It will be recalled that the contacts BU3 and CU3 remain closed.) The resistors BR and CR supply sufcient current to pick up the relay 2E but do not supply sufficient current to pick up the relay 3E. The relay 2E closes its make contacts 2EVI, but this has no immediate effect on the operation of the system for the reason that the contacts 2S2 are still open.

Upon expiration of the time required for the interval relay 2S to drop out, the contacts 2SI open to interrupt the energization of the in- 18 terval relay 3S and this relay starts to time out. At the same time the contacts 2S2 close to complete through the contacts 2EI an energizing circuit for the start relay US. The start relay closes its contacts USI to complete an energizing circuit for the auxiliary start relay BS as follows:

LI, BU2, BS, BN2, USI, L2

The start relay BS opens its contacts BSI to interrupt the energization of the relay IS. The contacts BSZ open to interrupt the energization of the next lamp BNL and the hal1 lantern for the car B. The contacts BSS close to illuminate the start lamp BSL. The car attendant now is informed that he is to start from the dispatching iioor. Contacts BS4 open to deenergize the next relay BN. Contacts BSS close to establish a holding circuit around the contacts BN2 and USI.

It should be noted that the dispatching interval for the car B is equal to the sum of the intervals required for operation of the relays IS and 2S. Because of the operation of the expediter relay 2E, the dropout time of the interval relay 3S is not included in the dispatching interval for the car B. Consequently the car B may be said to have a medium dispatching interval under the assumed conditions.

The relay IS opens its contacts IS2 and closes its contacts ISI. The contacts IS3 open to interrupt the energization of the expediter relays 2E and 3E. The contacts IS4 close to energize the interval relay 2S. The interval relay 2S closes its make contacts ZSI to energize the interval relay 3S. Also the contacts 2S2 are opened to prevent subsequent energization therethrough of the start relay US.

The next relay BN upon deenergization closes its break contacts BNI to complete the following energizing circuit for the winding of the electromagnetic clutch RC:

LI, CUI, RC, ANI, BNI, CNI, DNI, L2

(The contacts CUI remain closed as long as the car C is at or adjacent the upper dispatching floor.)

The cam 4I now rotates until it closes the switch CY. This completes the following circuit for the next relay CN:

Ll, CU2, CN, est, CY, Lz

The next relay CN opens its contacts to interrupt the energizing circuit for the winding of the electromagnetic clutch RC. The contacts CN2 close but have no immediate effect on the operation of this system. The contacts CN3 close to illuminate the next lamp CNL and the hall lantern of the car C. The car attendant for the elevator car C now is notied that his car will be the next to leave the dispatching oor and he starts to load his car.

When the car B leaves the dispatching iloor, the brush B35 separates from the contact segment Bc to deenergize the upper terminal relay BU. The upper terminal relay opens its contacts BUI, but this has no immediate eiect on the operation of the system. Contacts BUZ open to deenergize the start relay BS. Contacts BU3 open, but such opening has no immediate effect on the operation of the system.

The deenergization of the auxiliary start relay closes the break contacts BSI. This completes the following circuit for the winding of the electromagnetic clutch SC:

LI, ISI, SC, ASI,BSI, CSI, DSI, L2

As a result, the cam 43 rotates to .initiate the measurement of a dispatching interval and ultimately closes the switch S to energize the relay IS. The relay IS closes its contacts IS2 to establish a holding circuit around the switch S. In addition the contacts ISI open to deenergize the Winding of the electromagnetic clutch SC. The spring 45 returns the cam 53 to its starting position. The contacts ISS close to complete an energizing circuit for the expediter relays 2E and 3E through the resistor CR. However, the amount of current suppliedA to the expediter relays is insufficient to cause pickup of either oi the expediter relays,

The contacts ISQ open to interrupt the energization of the interval relay 2S. The interval relay consequently starts to time out.

Upon the expiration of the time required for the interval relay 2S to drop out, the contacts 2SI open to interrupt the energization or' the interval relay 3S. The interval relay 3S consequently starts to time out. In addition the contacts 2S2 close, but have no immediate eiect on the operation of the system for the reason that the contacts ZEI are open.

Following expiration of time required ior the interval relay 3S to drop out, the contacts SSI close to complete an energizing circuit for the start relay US. This relayl US clases its contacts USI to complete the following energizing circuit for the auxiliary start relay CS:

LI, CU2, CS, CN2, USI, L2

The auxiliary start relay opens its contacts CS! to deenergize the relay IS. The contacts CS2 open to interrupt the energization of the next lamp CNL and the hall lantern for the car C. The contacts CS3 close to illuminate the start lamp CSL. This noties the car attendant for the car C that he should start his car away from the dispatching floor. Opening of the contacts CSI! deenergizes the next relay CN, and closing of the contacts CSB establishes a holding circuit around the contacts CN2 and USI.

The next relay CN closes its contacts CNI to prepare the winding oi the electromagnetic clutch RC for subsequent energization. Opening of the contacts CN2 and CNS has no immediate eiect on the system.

It should be observed that thev dispatching interval required for the car C is the sum of the intervals introduced by the relays IS, 2S and 3S. Consequently, when three cars simultaneously are at the dispatching floor, the iirst of the cars to leave the dispatching floor is dispatched after the expiration of a short interval. The second car to leave the dispatching floor is dispatched after the expiration of a medium dispatching interval. The third car to leave the dispatching iioor leaves the dispatching iioor after the expiration of a long dispatching interval.

Because of the staggering in the dispatch of the cars, negligible bunching of the cars can occur either at hte dispatching ioor or at iioors displaced from the dispatching floor. At the same time optimum service is provided for intending passengers.

The last reference to the relay IS relatedY to its deenergization as a result of opening of the contacts CSI. The contacts ISE open to interr11-pt the holding circuit around the switch S. The contacts ISI close to prepare the winding of the electromagnetic clutch SC for subsequent energization. The contacts IS3 open to deenergize the expediter relays 2E and 3E. The con- 20 tacts ISA close to energize the interval relay 2S'. The interval relay 2S closes its contacts 2SI to energize the interval relay 3S. Also contacts 2S2 open but have no immediate eiect on the operation of the system. The interval relay 3S opens its contacts 3SI.

When the car C leaves the dispatching floor it moves the brush C35 away from the associated contact segment Cc of the car selector. The resulting deenergization of the upper terminal relay CU opens the contacts CUI. Such opening has no immediate eiect on the operation of the system. Contacts CU2 open to deenergize the auxiliary start relay CS. Contacts CU3 open but have no immediate effect on the operation of the system.

Upon departure of the elevator car C and the resulting closure of the contacts CSI of the auxiliary start relay, an energizing circuit is completed for the winding of the electromagnetic clutch SC. The cam i3 thereupon'rotates to initiate the measurement of a dispatching interval for the next car to arrive at the dispatching terminal. The relay CS also closes its contacts CS2 and CSLI, but such closures have no immediate eiiect on the system. Contacts CS3 open to extinguish the start lamp CS2. Opening of the contacts CS5 has no immediate. effect on the system.

FIGURE 3 The dispatching terminals for the upper and lower dispatching iloors may be independently adjustable. For example in some elevator installation the service calls may be predominantly in one direction, as in the down direction. Under these conditions the cars may be dispatched with shorter dispatching intervals from the upper dispatching loor than from the lower dispatching floor. A circuit suitable for such independent adjustment is illustrated in Fig. 3.

Each oor is provided with an up switch and a down switch which may be manually operated by intending passengers. Preferably these switches take the form of contacts on the conventional floor call registering relays employed in elevator systems. g

In Fig. 3, a differentially-operated resistor 55 is adjusted through contacts of the up and down floor call registering relays. For example, each of the up-call registering relays has make contacts IURI to 5URI connected through a separate resistor 51 to one terminal of a winding 59 of the differentially-operated resistor. In an analogous manner each of the down-call registering relays has make contacts ZDRI to SDRI connected through a separate resistor 6I to one terminal of the remaining winding 63. of the differentially-operated resistor. The remaining terminals of the windings 59 and 63 are connected through a conductor 65 to the bus LI. Each ofthe call registering relays completes a circuit for its associated resistor 51 or 6I between the buses LI and L2.

The windings 59 and 63 operate diierentially on magnetic cores which rotate a tap 61 about an axis. The tap is biased towards a predetermined position by means of suitable springs 69..

The position of the tap 6'!r with respect to its associated resistors 'II is determined by the difference between the service demands in the. up and down directions. The adjustable resistor of Fig. 3 may be employed in place of the resistor 41 or 49 of Fig. 2, if desired, to vary the dispatching interval for one of the dispatching iioors as a function of the difference in service demand for the two directions of travel of the elevator car.

FIGURE 4 Fig. 4 shows a number of refinements which may be added to the system of Fig. 2. When the additions of Fig. 4 are employed, the switch 5I of Fig. 2 preferably is opened to remove the eX- pediter relays from service.

In Fig. 4 an instant dispatch relay IDU is provided for additionally controlling the dispatch of elevator cars from the upper dispatching floor. Referring to Fig. 2, it will be observed that the instant dispatch relay IDU has contacts IDUI which are independently effective for energizing the start relay US.

The instant dispatch relay IDU may be of the inverse time-delay type. Such relays are well known in the art and have a time delay which varies as an inverse function of the magnitude of the current energizing the relay. The relay then may be energized with current having a magnitude dependent on the number of elevator cars at or adjacent the associated dispatching oor in a manner hereinafter set forth. However, it will be assumed that the instant dispatch relay IDU is of the instantaneously-operating type and that discrimination between the numbers of cars adjacent the dispatching floor is obtained by means of a resistor I2 which may be connected in parallel with the relay IDU through contacts KI and UTI of expediter relays K and UT.

It will be recalled that the upper terminalv relays AU, BU, CU and DU are energized respectively in response to the presence of the associated elevator cars at or adjacent the upper terminal floor. These relays have make contacts AU4, BU4, CU4 and DU4 which are effective for connecting in parallel resistors ARU, BRU, CRU and DRU through which the instant dispatch relay IDU may be energized. The parameters may be such that with the resistor 12 connected in parallel with the instant dispatch relay IDU, three of the resistors ARU, BRU, CRU and DRU must be connected in parallel for the purpose of supplying suiiicient current to pick up the relay IDU. Under these conditions the presence of three or more elevator cars adjacent the upper dispatching oor supplies suflicient current to pick up the relay IDU and thereby to start instantaneously an elevator car from the associated dispatching oor. It will be observed that the instant dispatch relay is energized through break contacts USZ of the start relay US. Consequently, if the start relay has already operated to provide a start signal, the contacts U82 are open and the instant dispatch relay IDU is ineffective.

The parameters further may be so selected that if the resistor 'I2 is not connected in parallel with the instant dispatch relay IDU, current supplied through a pair of the resistors ARU, BRU, CRU and DRU suffices to pick up the relay IDU. Under these conditions the presence of two cars adjacent the associated dispatching floor suffices to pick up the instant dispatch relay for the purpose of starting instantaneously one of the cars from the dispatching floor.

Provision also is made for instantaneously starting an elevator car when only one car is present adjacent the dispatching floor. Such dispatching is effected by means of contacts of position relays PI, P2 and P3, and of service demand relays R0, RI, RZ'and R3. Various combinations of these contacts are effective for, bypassing the resistors ARU, BRU, CRU and DRU. When any of these combinations is present, sufcient current is passed to pick up the relay IDU promptly, regardless of the number of elevator cars adjacent the upper dispatching floor. The position and service demand relays will be discussed in greater detail below.

The connection of the resistor 'I2 in parallel with the relay IDU is controlled in part by the expediter relay K. This expediter relay K is connected for energization through various combinations of the contacts of the position and service demand relays. The expediter relay K interrupts the connection of the resistor I2 across the relay IDU when a predetermined service demand exists on the system with no elevator car in position to supply reasonably prompt service to the service demand.

Under some conditions it may be desirable to modify the dispatching from the upper terminal in accordance with the dispatching from the lower terminal floor. To this end, an auxiliary expedter relay UT is provided for controlling additionally the connection of the resistor I2 across the instant dispatch relay IDU. The relay UT is controlled by contacts IDL2 of an instant dispatch relay for the lower dispatching iioor, The relay UT for the upper terminal is energized through the contacts IDL2 and contacts LT2 of an auxiliary relay LT for the lower dispatching oor. If the service demand for an elevator car at the lower dispatching floor results in an operation of the instant dispatch relay IDL for the lower dispatching floor, the contacts IDL2 and LT2 are closed to energize the relay UT for the upper dispatching iioor. The last-named relay opens contacts UTI which control the connection of the resistor I2 in parallel with the instant dispatch relay IDU. Also a holding circuit is established for the relay UT through make contacts UT2 thereof and break contacts U83 of the start relay.

In order to determine the need for expedited dispatching, the service demand is ascertained for various zones of the building served by the elevator cars. Although the system is applicable to buildings having various numbers of floors, it will be assumed in Fig. 4 that the building served by the elevator cars has 17 ocrs. These floors are divided into zones represented by the service demand relays R0, RI, R2 and R3. The service demand R0 is associated with oors 14, 15 and 16. The service demand relay RI is associated with oors 10, 11, 12 and 13. The service demand relay R2 is associated with cors 6, 7, 8 and 9. The service demand relay R3 is associated with fioors 2, 3, 4 and 5. The number of floors in each zone and the number of zones may be selected in accordance with the requirements of each elevator installation.

Each of the oors has a switch or a call registering relay provided with contacts which may be operated by an intending passenger for controlling the energization of the associated service demand relay switch. For example, the 16th floor has contacts IIDR2 which when closed connect a resistor IGZ in series with the associated service demand relay R0. Similarly, contacts I5DR2 and I4DR2 control the connections of resistors I5Z and I4Z to the service demand relay R0.

Each service demand relay may be designed to pick up when any predetermined service demand is reached for the associated zone. For example, it will be assumed that each of the service demand-.relays picks up when energized by current flowing through rat leasttwo of the resistors associated, therewith. It will be understood that eachof the down oor call registering relays closes its contacts in response to actuation of a floor button for the associated floor. The contacts remain closed until the floor call is answered.

The position of the elevator cars may be ascertained in any suitable manner. For example, the selector for the car A is provided with a row of contact segment Af which are engaged successively by brushes 8l and 82 as the car moves from floor to floor. The contact segments in Fig. 4 are labeled AJSV to AfIS. By inspection of Fig. 4, it will be noted that the position relay PI is energized when any of the segments AM, Afl5 or Afl' engages one of the brushes 8l or 82. A circuit for the position relay is completed through contacts AXI of a direction switch which are closed when the car is conditioned for movement in a down direction. Such direction switches may be manually operated but preferably are automatically operated in a manner well known to the art; In an analogous manner the position relay P2 is energized when any of the associated contact segments Afl to Afi is engaged by one of the brushes 8l or 82. The position relay P3 is energized when any of the contact segments Af to AIS is engaged by one of the brushes 8| or 82, and the car is set for down travel. The brushes may be arranged to contact each segment before contact is broken with the immediately proceding segment.

It will be understoodthat a row of segments similar to the segments Af to Afl is provided foreach of the elevator car selectors. The arrows in Fig. 4 are to be connected to corresponding segments for the remaining elevator cars B, C

and D. Each of the cars also would have brushes similar to the brushes 8| and 82 for engaging the associated contact segments. Consequently, when the position relay Pl is picked up it indicates that at least one of the elevator cars A, B, C or D is positioned in the zone including oors 14, and 16, and is set for travel in the down direction. The position relay P2 conveys similar information for cars positioned in the next lower zone. Similarly the position relayy P3 when picked up indicates that a car set for dow-n travel is positioned in the associated zone.

It will be noted that the service demand relays R8 to R2 are connectedl to their associated resistors through appropriate contacts on the position and service demand relays. Thus the service demand relay R0 cannot be energized if one or more cars set for down travel is positioned in the associated zone. This is true for the reason that the service demand relay R0 must be energized through the break contacts Pl-S of the position relay PI. Consequently, if the contacts PI-3 are open signifying the presence of a car set for down travel in the associated zone, the service demand relay R0 cannot be energized.

Similarly, if elevatorV cars are set for down travel in the zones of position relays Pl and P2 (contacts PI-ll and 132-4 are open), the service demand relay RI can not be energized. If elevator cars positioned in the zone represented by floors 6 to 9 and in either of the higher zones (contacts P3-5 and either PI-5 or 1PZ-5 are open), the service demand relay R2 cannot be energized.

If a down-traveling car is in the-zone of the position relay P2, the service demand relay RI can stil1 be energized through either of two cir- 24:l cuits. If no car is in thezone of position relay PI, and if a service demand exists for the lower zone represented by the service demand relay R2, the service demand relay VR-I can be energized through the contacts R2-1 and Pl-4. If no cars are in the zones represented by the position relays PI and P3, and if a servicey demand existsv for the lower zone represented by relay R3the.

relay RI can be energized through the contacts R3-5, P3-ll and PI-li.

If no cars set for down travel are positioned in the zones represented by the relays PI and P2 and. if a servicedemand exists in the zone represented by the service demand relay R3, the service demand R2 can be energized throughthe contacts R3--6, PI-5 and P2--5;

Preliminary operation Figure 4- It is believed desirable at. this. stage to discuss briefly a typical operation ofthe portion of the system of Fig. 4 thusfar. specically described. The purpose of the position and service demand relays is to expedite the dispatch of a car fromV the-upper terminal theevent that a service demand exists in azone with no car positioned to answer the service demand` with reasonable promptness. (A similarsystem may be employed for dispatching from thelower dispatching floor if sodesired. For present purposes, it will be assumed that the service demandof buildingis predominantly ina downY direction.)

The system further contemplates additionally expediting the dispatching of elevator cars inthe event that service demands exists in two zones with no car in position to, provide reasonably. promptservice therefor.

Referring rstto the relay K, it will be observed that an energizingk circuit for the relay is completed through the` break contacts RI-4, RZ- and R3-3 ofthe service demandrelays. Consequently, the relay K normally is in ener.- gized or picked-up condition. As long as the relay K remains energized andthe cars remain properly distributed, the cars will arrive at the upper dispatching floor andV will be dispatched at intervals. substantially equal to the sum of the intervals required forclosure of the switch S and the dropout of the relays 2S and 3S of Fig. 2. Shouldthree or more elevator carsV accumulate at or adjacent the upper dispatching floor, suffi'- cient current is supplied through three sets of the contacts AUll to DU4 to the instant dispatch relay IDU todispatch one of the cars. immediately from the terminal.,

Should a service demand on the system occur.

the picking up vof the relay R3' to open the con-v tacts R3--3, the relay K drops out to expedite the dispatch of carsfrom the upper terminal. However, if under the same circumstances a car is positioned above the zone of the service demand` relay R3, the relay K' does not drop out. For example, if a oar conditioned for down travel were positioned in the zone of the'position relay P3, contacts P3--3 would be closed to establish a shuntl around the contacts R3-3. Consequently, the relay K would not drop out.

25 As a further example, 1f a car were positioned in the zone represented by the position relay P2 and were conditioned for down travel, contacts P2-3 would be closed to maintain the energization of the relay K through the circuit LI, K, RI-4, P2-3, R2-4, L2

If a car were in the zone represented by the position relay Pl and conditioned for down travel, the relay K would be maintained energized through the circuit In an analogous manner, it will be found that if any of the service demand relays R0, RI or R2 is picked up with no down traveling car positioned in a zone above the picked-up service demand relay, the relay K will drop out to expedite the dispatching of an elevator car from the upper dispatching floor.

As a further example, it will be assumed that a service demand results in the pickup of the relay R2 (contacts R2-3, R2--4, R2-5, R2-6 are open). If no cars are conditioned for down travel in the zones represented by the position relays PI or P2 (contacts Pl--2 and P2-3 are open), the relay K drops out. If a car is positioned in the zone represented by the position relay Pl and is conditioned for down travel, the contacts PI-2 are closed, and the relay K is maintained in picked-up condition through the circuit Ll, K, Pl-2, Rl-5, R3-5, L2

If service demands exist in two or more of the zones at the same time with no car in position to answer the service demands with reasonable promptness, the instant dispatch relay IDU is energized. If a single car is present at the upper terminal, the car is dispatched instantly by such energization of the relay IDU. If no car is present at the upper terminal, the rst car to reach the upper terminal is instantly dispatched. The energization of the relay IDU under these conditions is effected by connecting the relay directly across the buses LI L2 through suitable contacts of the position and service demand relays.

For example, let it be assumed that no car is positioned in any of the zones represented by the position relays PI, P2 and P3. cumstances, the break contacts Pl-l, P2-I and P3-I are closed. If service demands exist in the zone represented by the service demand relay R3 and the zone represented by either of the service demand relays R or RI, the make contacts R3-l and RU-I or Ri-I are closed. Thus a circuit is completed for energizing and picking up the relay IDU as follows:

Ll, Pl-i, Pz-l, 12a-l, Ra-l, Ri-l or Rc-l, Usz, IDU, L2

Under these cir- Again a car is dispatched as promptly as possible from the upper terminal.

If no car is present in the zone represented by the position relay Pl and service demands exist in the zones represented by the service demand relays RI and R0 (make contacts Rl-3 and Ril-3 are closed), a circuit is established for the instant dispatch relay IDU as follows:

L l, P-, R|--3, Ril-3, US2, IDU, L2

As a iinal example, if no car is positioned in either of the zones represented by the position relays P2 and P3 (break contacts P2-2 and P3-2 are closed) and service demands exist in the zones represented by the position relays R2 and R3 (make contacts R3-2 and `ft2-2 are closed), the following energizing circuit is established for the instant dispatch relay IDU:

It will be understood that when these circuits are established the full voltage across the buses Ll and L2 is applied across the relay IDU.

When the relay IDU is energized, its contacts IDUI (Fig. 2) close to energize the start relay US. The start relay dispatches a car as set forth in the discussion of Fig. 2.

If similar service demands exist for up floor calls, a dispatcher may be provided for the lower dispatching floor which is similar to that described for the upper dispatching oor. For the purpose of discussion, however, it will be assumed that the service demands are present only-for calls in the down direction. Under these conditions when the dispatch of a car from the upper terminal is expedited, the dispatch of a car from the lower dispatching floor similarly may be expedited.

The dispatcher for the lower dispatching oor includes a start relay LS and relay contacts 3SL| which correspond respectively to the start relay US and contacts 3S| associated with the dispatcher for the upper dispatching floor. It will be understood that when a car leaves the lower dispatching floor a timer similar to that including the switch S and the relays 2S and 3S of Fig. 2 measures a dispatching interval and nally closes the contacts SSL! to energize the start relay LS. The relay LS operates in a manner similar to that of the relay US for the upper dispatching floor to start the next car from the lower dispatching oor. Contacts SELI, 2SL2 and 2ELI of Fig. 4 correspond to the contacts SEI, 2S2 and 2E! of Fig. 2.

In order to expedite the dispatch of elevator cars from the lower dispatching floor, the instant dispatch relay IDL is provided and this relay corresponds to the relay IDU provided for the upper dispatching floor. The relay IDL may be energized through resistors ARL, BRL, CRL and DRL which correspond to the resistors ARTT to BRU provided for the dispatcher associated with the upper dispatching floor. Connections of the resistors ARL to DRL to the instant dispatch relay IDL are controlled by -contacts AL4 to DIA of the lower terminal relays AL to DL.

A resistor 13 is provided which may be connected in parallel with the winding of the relay IDL through relay contacts 'II and LTI. The resistor 13 corresponds to the resistor 12. When it is connected in parallel with the winding of the relay IDL, the resistor 13 may require the presence of three or more cars at or adjacent the lower dispatching floor before sufl27 cient current is Vvsupplied to pick up the relay IDL. If ether of the contacts TI or LTI are open, the parameters may be such that the presence 'of two .cars at or adjacent the lower dispatching `floor suihces to pick up the relaylDL.

When the dispatch 'of an elevator car from the upper dispatching oor is expedited, it may be desirable Lto expedite similarly the dispatch of an elevator .car from the lower` dispatching loor. 'Such `expedition may be effected by the relay 'I' which iis .controlled Aby contacts K2 and IDU2. When the relay K drops out to expedite the dispatch of a car from the -upper dispatching floor,

it opens its make contacts KI and closes its break contacts K2. The upper dispatching oor relay .IDU picks up when two cars are at or adjacent the upper dispatching floor and closes its makes Vcontact IDUZ. This completes an energizing circuit for the relay T. The relay T establishes `a holding circuit through .its make contacts T2 vandbreak contacts LS3 of the start relayLS for the lower dispatching hoor. The relay T also opens its break contacts TI to interrupt .the parallel connection of the resistor I3 across the relay IDL. The relay IDL now can pick up when only .two cars are at or adjacent the lower dispatching hoor. When a car .thereafter is dispatched from the lower terminal, the contacts L53 of the lower terminalk start relay open to reset the relay T.

uIt may be desirable to expedite the dispatch of .anelevator car when a predetermined service .demand Ais registered by the car buttons Awithin the elevator car. For example, let it .be .assumed that lthe elevator car A has been selected as the next car to leave the lower dispatching Aiioor (contacts ANLII of a next relay for the dispatcher for the lower dispatching Yfloor are closed. .Such a next relay corresponds to the next relay .AN Vfor the upper dispatching oor.) -Let it Vbe assumed further Athat the car A is vsetfor .up travel (contact AWI of an up .preference switch are closed. The Vcontacts may be manually closed but ordinarily are automatically operated ina manner well understood in the -art -when the car A is conditioned for upward travel.)

The -car A is provided with car call buttons which Vmay be actuated to stop the .elevator car at Aany of the floors served thereby. For each car'button actuated, one of the sets of contacts 2CRI to ICRI is closed. The contacts may be manually operated from within the ,car A. The operation of such car buttons is well understood .in the art.

Each of the sets of contacts ZCRI to ICRI `controls the connection of an associated resistor yZYto I6Y in circuit with a service demand relay ACC. When a predetermined number of the resistors lare connected in parallel, by opv-er-ation -of their associated contacts ZCRI to IVECRI, the relay ACC is energized suiciently to fpick up. For example, the service demand relay ACC may be designed to pick up in response to the connection therethrough of five `or more of the resistors ZY to IBY, When it lpicks up the relay ACC closes its contacts ACCI. If the Ycar is at the lower dispatching oor, the

make -contacts ALS of the lower terminal reflajy are .closed and a circuit is completed for the relay LT. This relay when lenergized opens sits break contacts LTI to vinterrupt the connecftion of the resistor 13 across the relay IDL.

Consequently, the relay IDL picks up in response to the presence of only two cars adjacent the wlower dispatching floor. It will be understood that each of the remaining elevator cars is provided with a relay BCC, CCC or DCC which is energized in response to operation of a predetermined number of the associated car buttons in a manner analogous to the operation of the relay ACC iorthe car A. Each of the relays has make contacts which control in part the energization of the relay LT. Contacts ALS to DL5 are associated with the contacts ACCI to `DCC I, respectively, in the manner clearly showninEig. .4.

When one Yof .the relays YACC toDCC operates .to ,expedite the dispatch of an elevator car from the .lower dispatchingioor, it may be rdesirable .to `expedite simultaneously the dispatch of an .elevator car from the upper dispatching floor. This vis efiected by a relay UT which has break .contacts `UTI positioned to interrupt .the connection of the resistor 'I2 across the relay IDU. Such interruption of the connection of the resistor 'I2 expedites the dispatch Yof a car from the upper .dispatchingloorin .a manner which will be apparent from .the preceding discussion.

When the relay LT is picked up to expedite the dispatch or" an elevator .car from the `lower dispatching oor, make contacts .LTE are .closed -to prepare the relay UT for energization. When the instant dispatch relay YIDL for the lower dispatching iioor picks up, make contacts IDL2 close to complete an energizing circuit for the relay UT. A holding circuit for the relay UT is established through the make contacts UT2 and break contacts USS of the start relay for theupper dispatching iioor. When the relay US thereafter operates to dispatch a car from the upper terminal floor, `the-contacts USS open to deenergize the relay UT.

.Ii desired, relays similar to the relays ACC to DCC and LT may be provided for expediting the dispatch elevator cars from the upper dispatching floor in response to the car call service demand. However, in most elevator installations,

such relays are not required for the upper dispatching iioor.

Operation of Figure 4 It is believed advisable at this stage to review brieiiy a typical operation of the system including' components shown in Fig. 4.

Let it be assumed that the car A arrives at the upper dispatching floor. This car is selected as the next car to leave the dispatching oor by energization of rthe next relay `AN in the manner discussed with reference to Fig. 2. Also the dispatcher for the upper dispatching iioor measures a dispatching interval for the car A by operation of the interval relays IS, 2S and 3S, in a manner which will be clear from the discussion of the operation of Fig. 2. It will be assumed that the switch 5I of Eig, 2 is open. It will also be understood that the car A on arriving at the upper dispatching floor establishes an energizing circuit for its upper terminal relay AU.

Referring to Fig. 4, it will be'noted that contacts AU4 close on arrival of the elevator car adjacent the upper dispatching hoor, but the resulting energizationof the instant dispatch relay IDU is insufficient to pick up the relay Let is be assumed next that a down oor .call is registered at the 10th floor. As a result o1 such registration, the down floor call registering relay for the 10th floor picks up and closes its make contacts I BDR2. However, the resulting ener- 29 gization of the service demand relay RI is insuflicient to pick up this relay.

It will be assumed next that the car B arrives at the upper dispatching floor. Such arrival results in energization of the upper terminal relay BU. This relay closes its contacts EUA, out the resulting energization of the instant dispatch relay IDU still is insucient to pick up the relay. (It will be understood that the contacts KI and UTI are closed to connect the resistor 'l2 across the relay IDU.)

At this stage a down oor call is registered at the 11th floor. The resulting closure of the make contacts I IDRZ connects the resistors IIZ and IOZ in parallel for the purpose of energizing the service demand relay RI. It is assumed that no car is in the zone represented by the position relay P2 and suiiicient current now is supplied to the service demand relay Rl to pick up this relay. The relay Rl closes its make contacts R|-|, RI-2, RI-3 and opens its break contacts RI-4, Rland RI-E.

Closure of the contacts RI-l, Rl-2 and RI-3 has no immediate eiect on the operation of the system for the reason that contacts R3-l, RZ-I and RQ-3, respectively, are open.

However, the contacts RI-4 in opening deenergize the relay K and this relay drops out to open its make contacts KI and close its break contacts K2. The opening of the contacts Kl interrupts the connection of the resistor 'l2 across the relay IDU and this relay now is energized suiiiciently by the presence of two cars at or adjacent to the upper terminal to pick up. The relay IDU in picking up closes its make contacts IDUI and IDU2. The contacts IDUI (Fig. 2) complete an energizing circuit for the start relay US and this relay operates to start the car A in the manner discussed with reference to Fig. 2.

The closures of the contacts IDU 2 and K2 complete a circuit for the relay rI'. The relay T in turn completes a holding circuit through the contacts T2 and L53. In addition, the energization of the relay T opens contacts Tl to interrupt the connection of the resistor '!3 across the relay IDL. I'he relay IDL now can be energized by the presence of two elevator cars at or adjacent to the lower dispatching floor. Consequently in expediting the dispatch of a car from the upper dispatching door, provision is made simultaner ously for expediting the dispatching of an elevator car from the lower dispatching floor.

When the car A leaves the upper dispatching floor, contacts AU4 of the upper terminal relay AU reopen. Th energization of the relay IDU is no longer suflicient to maintain the relay picked up even though the contacts USZ reclose, and this relay consequently now has open contacts IDUI and IDU2. However, the relay K remains dropped out until the car A has answered the down call from the 11th floor. When this call is answered, the contacts IIDRZ open and the energization of the relay Rl no longer is sufficient to maintain the relay picked up. Consequently, contacts RI-ll reclose to energize the relay K. This relay recloses its contacts Kl to reconnect the resistor 5| across the relay IDU. Contacts K2 open but have no immediate effect on the operation of the system. Since the contacts TI are open, arrival or presence of two cars at or adjacent the lower 'terminal floor results in energization of the relay IDL and dispatch of a car from the lower terminal iioor. The sequence for dispatching the car following energization of the relay IDL will be understood from the explanation of the dispatch of a car from the upper terminal floor in response to energization of the corresponding relay IDU. When the start relay LS is energized to dispatch 'the car from the lower terminal floor, the contacts L83 open to deenergize or reset the relay T.

It will be assumed next that the cars A and B are at the upper terminal licor when down iioor calls are registered at the 10th and 11th iioors, and that the car C is in the zone represented by the position relay Pl and is conditioned or travel in the down direction. Under such circumstances, the relay Pl would be picked up and the make contacts P l-2 would be closed. Because of the closure or" the contacts Pl-Z, energization of the relay K is maintained despite the opening of the contacts RI-4. The alternate energizing circuit for the relay K may be traced as follows:

LI, K, Pl-Z, R2-5, R3-5, L-2

Consequently, the resistor 'I2 would remain connected across the relay IDU and the car A would be dispatched upon the expiration of its regular dispatching interval. In the meantime the car C in travelling downwardly would pick up the floor calls on the 11th and 10th iioors to deenergize the service demand relay Rl.

In the preceding discussion, reference was made to the door call registering relays. Although such relays are well known in the art, it is believed desirable to show a typical circuit therefor. Referring to Fig. 5, a oor push button GD is assumed to be located at the 6th floor. When actuated, this push button completes a circuit for a floor call registering relay BDR. The registering relay establishes a holding circuit around the push button 5D through contacts SDRB.

It will be understood that the selector for each of the elevator cars has a row of contact segments (Ag for the car A) which are engaged successively lov a brush (84 for the car A) as the associated elevator car moves past the oors served thereby. The contact segment for each of the floors is energized throughout the contacts of the associated floor call registering relay. Thus the contact segment BAU is connected to the bus L! through the contacts 6DR3. The bus also is connected through the contacts 6DR3 to similar contact segments for the other elevator cars of the bank by means of a connection 83.

Each of the elevator cars has a stopping relay connected between the associated brush 84 and the bus L2 through contacts of a down preference switch. Thus the car A has a stopping relay AST which is connected between the brush 84 and the ous L2 'through contacts AX2 of a down preference switch. The contacts AXZ are closed when the car is conditioned for down travel. They may be closed manually, but ordinarily they are closed automatically in a manner well understood. in the art. When the brush 84 during down travel of the car A reaches the contact segment GAg which is connected to the bus Ll, the relay AST is energized to stop the elevator car at the 6th oor. The mechanism for so stopping the elevator car is well understood in the art.

Each of the selectors for the elevator cars is provided with a row of contact segments for cancelling the iioor calls. For example, the car A has a row of contact segments Ah which are engaged successively by a brush 86 as the car moves pa-st the doors served thereby. Each of the contact segments is connected through an associated cancellation coil and make contacts of the iioor call registering relay to the bus LI. Thus the contact segment SAh is connected through the cancellation ccil GER and the contacts SDRB to the bus LI. The cancellation coil ER is Wound oppositely to the winding of the relay i-DR. Consequently when the cancellation coil is energized, it neutralizes the force exerted by the winding of the relay DR on the contacts BDRS and the contacts consequently reopen. The coil GER is connected to cancellation contact segments associated With the other elevator cars through a connection 85.

The brush 86 is connected to the bus L2 through contacts AXS of the down preference switch. As the car A answers the oor call at the 6th fioor, the brush 85 engages the contact segments Ah to energize the cancellation coil GER. This cancels the iloor call for the 6th floor.

Although the invention has been described with reference to certain speciiic embodiments thereof, numerous modifications falling within the spirit and scope of the invention are possible.

I claim as my invention:

1` An elevator dispatching system for a plurality of elevator cars serving a plurality of floors, comprising a non-rotational dispatcher for dispatching the elevator cars from one of the iioors, said dispatcher comprising a selecting device for selecting successively each car to be dispatched from the dispatching floor, a timer for 'determining a first timing interval for starting successive cars from the dispatching floor, and secondary timing mechanism responsive to the presence of a predetermined irst number of cars at the dispatching floor for changing the timing interval for starting two successive cars to two intervals which differ from each other.

2. An elevator dispatching system for a plurality of elevator cars serving a plurality of oors, comprising a dispatcher for dispatching the elevator cars from one of the floors, said dispatcher comprising a selecting device for selecting successively each car to be dispatched from the dispatching floor, a timer for determining a rst timing interval for starting successive cars from the dispatching iioor, and secondary timing mechanism responsive to the presence of a predetermined first number of cars at the dispatching oor for changing the timing interval to a second value, said secondary timing means comprising an adjuster responsive to the presence of a second predetermined number of cars at the dispatching oor for changing the timing interval to a third value.

3. An elevator dispatching system for a plurality of elevator cars serving a plurality of oors, comprising a non-rotational dispatcher for dispatching the elevator cars from one of the floors, said dispatcher comprising a selecting device for selecting successively each car to be dispatched from the dispatching floor, a timer for determining a nrst timing interval for starting successive cars from the dispatching floor, and secondary timing mechanism responsive to the presence of a predetermined rst number of cars at the dispatching iioor for changing the timing interval, a next device for each of the elevator cars, actuation means responsive to the selecting device for actuating the next device for the car selected to leave the dispatching floor, a start device for each of the cars and operating means eiiective onlyafter actuation of the next device and after expiration of the timing interval for each of the elevator cars for operating the start device of the car having an actuated next device.

4. An elevatorl dispatching system for a plurality of elevator cars serving a plurality of floors, comprising a dispatcher for dispatching the elevator cars from one of the floors, said dispatcher comprising a rst timer and a second timer for delaying dispatch of a car, selective means Yeffective only after successive operations of the iirst and second timers for dispatching the next car to be dispatched from the dispatching oor, and an expediter responsive to the presence of a predetermined number of cars adjacent the dispatching iloor for rendering the second timer ineffective for delaying dispatch of a car to be dispatched from the Vdispatching iioor.

5. A system as claimed in claim 4 wherein the expediter is responsive to a second predetermined number of cars adjacent the dispatching floor for rendering both of the timers ineffective for delaying dispatch of the next car to be dispatched.

6. An elevator dispatching system for a Vplurality of elevator cars serving a plurality of floors, comprising a non-rotational dispatcher for dispatching the elevator cars from one of the floors, said dispatcher comprising a non-rotational selecting device effective for selecting following their arrival at the dispatching iioor cars to be dispatched from the dispatching iioor, timing means eiective for establishing a dispatching interval between successive cars to be dispatched from the dispatching floor, said dispatching interval comprising the sum of a plurality of time increments, and an expediter responsive to the number of cars adjacent the dispatching floor for decreasing the number of said increments in a dispatching interval.

7. A system as claimed in claim 6 wherein each of the time increments is established by a separate timing relay, and the expediter operates in response to the number of cars adjacent Athe dispatching floor to render ineffective certain of the timing relays.

8. A system as defined in claim 6 in'combination with a signal for each of the cars, connections between the selecting device and the signals effective upon selection of a car to be dispatched for promptly operating the signal for the selected car to indicate that the selected car will be the next car to leave the dispatching floor, and means responsive to expiration of the dispatching interval for the selected car to dispatch the selected car from the dispatching oor.

9. A system as dened in claim 6 wherein said time intervals may be employed for defining a short dispatching interval, a medium dispatching interval and a long dispatching interval, said dispatcher When a single car is present at the .dispatching floor being effective for dispatching said car upon expiration of said long dispatching interval, said expediter being effective in response to the presence of a plurality of cars at thevdispatching floor for establishing the medium interval for the first car to be dispatched, and for establishing the long vdispatching interval for the second car to be dispatched, and said expediter being effective in response to a number of cars, larger than the plurality, at the dispatching floor for establishing the short interval for a rst car to be dispatched from the dispatching Boor, for establishing the medium interval for a second car to be dispatched from the dispatching floor and for establishing the long interval for a third car to be dispatched from the dispatching hoor.

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