US3315765A

US3315765A - Program computer for elevator system

Info

Publication number: US3315765A
Application number: US787985A
Authority: US
Inventors: John R Dinning
Original assignee: Toledo Scale Corp
Current assignee: Toledo Scale Corp; Schindler Elevator Corp
Priority date: 1959-01-20
Filing date: 1959-01-20
Publication date: 1967-04-25
Anticipated expiration: 1984-04-25

Description

April 25, 1967 J. R. DINNING 3,315,765

PROGRAM COMPUTER FOR ELEVATOR SYSTEM oo @p-aor 7 INVENTOR. JOHN R. DINNING ATTORNEY April 25, 1967 J. R. DINNING 3,315,765

PROGRAM COMPUTER FOR ELEVATOR SYSTEM INVENTOR. JOHN R. DINNING BY ,9 RNEYS ATT April 25, 1967 J. R. DINNING 3,315,765

PROGRAM COMPUTER FOR ELEVATOR SYSTEM Filed Jan. 20, 1959 5 Sheets-Sheet 5 JOHN R. DINNING ATTORNEYS United States Patent 3,315,765 PROGRAM COMPUTER FOR ELEVATOR SYSTEM John R. Dinning, Los Angeles, Calif., assignor to Toledo This invention relates to automatic elevator systems and in particular to trafiic sensing or measuring equipment that is effective to alter the program of operation of the elevator system in accordance with the trafiic demands as such demands occur.

It is customary to provide groups of automatic elevators with supervisory control equipment to correlate the operation of the several cars and thus improve the service rendered by the system of elevators. The supervisory control, for example, is ordinarily arranged to control the dispatching of the elevator cars from the terminal landings of the system, to control the starting of idle cars, and vary the general program of operation in accordance with the demand for service and the number of cars in operation.

In the ordinary automatic elevator installation a supervisory control is arranged to afford several types or programs of operation designed to meet different trafiic patterns. These different patterns of operation may either be set up by a clock mechanism in anticipation of the particular traffic demands or a supervisor or starter may observe the traflic and select the programs accordingly.

The principal object of this invention is to provide traffic sensing means for automatically selecting an appropriate program of operation and putting such program into operation.

-' Another object of the invention is to provide traffic sensing mechanism that is responsive to the number of down hall calls registered, the loading of the cars during their upward and downward travel, and the number of stops made by each car in the course of operation and that correlates these factors to select an appropriate pro- 1 gram of operation.

A still further object of the invention is to provide trailic measuring means arranged to provide a quantitative measurement of the traflic demand.

A still further object of the invention is to provide tratfic measuring equipment in the form of a bridge circuit in which the resistance of one arm of the bridge is varied according to the trafiic being sensed, and the resistance of a second arm of the bridge is varied to balance the bridge and indicate the trafiic level. The bridge is thus, in effect, a self-balancing arrangement such that the bridge detector need not be sensitive to levels of excitation but need only be sensitive to the direction of the unbalance and initiate corresponding corrections until the unbalance is removed.

More specific objects and advantages are apparent from the following description of a preferred form of the invention.

According to the invention a traflic counting relay system is energized to either add or subtract trafiic indicating units according to the traflic level then indicated by the relay system and the actual trafiic demand of the elevator system. The measured traffic levels, as indicated by the bridge circuit, are employed to select corresponding appropriate modes of operation of the elevator system.

A preferred form of the invention is illustrated in the accompanying drawings.

In the drawings:

FIG. I is a schematic illustration of a plurality of elevator cars arranged to serve a plurality of floors.

FIG. II is a fragmentary schematic diagram of a hall call registering circuit.

FIG. III is a schematic diagram of bridge circuits arranged to be responsive to demands for service.

FIG. IV is a schematic diagram of part of the operating mechanism for the trafiic demand counting mechanism and means for including stops made by each of the cars as part of the traflic count.

FIG. V is a schematic diagram of the relay counting system for counting and indicating the traffic demand as sensed by the bridge circuits shown in FIG. III.

FIG. V1 is a schematic diagram of a plurality of timing circuits arranged to be responsive to the traific measuring equipment for selecting appropriate operating patterns of the elevator system in accordance with such trafiic measurements.

These specific figures and the accompanying description are intended merely to illustrate the invention and not to impose limitations on its scope.

In an elevator system constructed according to the invention a plurality of cars 10a, 10b, 10c and 10d are suspended by cables 11 that run over sheaves or .pulleys 12 mounted on armature shafts 13 of hoisting motors 14. The cables 11 after passing over the pulleys 12 are connected to counterweights 15 that balance the dead weight of the cars 10 and a portion of the full passenger load therein. Each drive motor 14 is connected through leads 16 to a direct current generator 17 which in turn is driven by an alternating current motor 18. The motor 18 is normally energized directly from a three-phase power line whenever the car is to be placed in readiness for operation.

A floor selector machine 19, one for each car, is driven preferably through drive and synchronizing means connected to the armature shaft 13 and is arranged to switch control circuits in accordance with the travel of its car 10 up and down its path of travel. The floor selector machines may, alternatively, be driven 'by tapes or cables connected directly to the cars. Each floor selector machine 19 is connected through an electrical control cable 20 to a supervisory control panel 21 that may be energized through supply leads 22. The supervisory control panel 21 is also connected through signal cable 23 to a series of push buttons 24 for down calls and 25 for up calls, the push buttons being located at the various floors served by the elevator system.

The control circuits for operating the elevator system include a large number of relays and associated circuits a few of which are illustrated in the accompanying drawings. The contacts of relays are given the same reference numeral as the operating coils or the relays as a whole and are identified by line numbers in the accompanying drawings. Thus, in the code strip to the right of each figure, in line with each of the relay coils and after its reference character, is an indication of the number and location of contacts operated by such coil. The contacts are listed according to the lines in which they are located and those that are normally closed are identified by underscoring the line number.

The relay coils and/ or contacts operated by such coils are listed for ready reference. These are:

B-Brake relay CC--No car call relay DL-Down memory relay DO-Door limit relay HB--Hall button relay HCR-High call reverse relay IS-In service relay 82D, 83D, etc-Down hall call relays SlU, S2U, etc-Up hall call relays ULUp memory relay W-l, W-2, W-3Load weighing relays lF-First or lobby floor relay 3 430No hall call relay 471One car in service 473--Three cars in service 474-Four cars in service 531Up add detector relay 531R-Up add detector reset coil 531XUp add auxiliary relay 532--Down add detector 532RDown add detector reset coil 532XDown add auxiliary 533Up subtract detector 533RUp subtract detector reset coil 533XUp subtract auxiliary relay 534--Down subtract detector 534RDown subtract detector reset coil 534X--Down subtract auxiliary relay 535A -535G -Up traffic counting relays 536A -536G Down traffic counting relays 560-Light trafiic relay 581Up peak timer 582--Down peak timer 583--Up peak cancel timer 584-Down peak cancel timer These relays are conventional except for the

detector relays

531, 532, 533 and 534 which have a plurality of coils connected in series, as illustrated in lines 309 to 311 or 323 to 327, to secure the best sensitivity and having reset coils appearing at

lines

502 and 505. These detector relays preferably have magnetic contacts or magnetic latch characteristics to insure reliable operation of the contacts under weak current and thus require reset coils to separate the contacts as soon as a circuit responds to their closure. The up and down trafiic counting relays 535A through G and 536A through G are composite relays having a ratchet section for alternately operating certain of the contacts and having other contacts operated directly by the pawl mechanism of the relay so that they operate each time the operating coil is energized. The contacts that operate each time the coil is energized are indicated by a prime following the reference numeral, while those that are operated on alternate releases of the energizing power are indicated without any special reference.

Referring to FIG. II, a hall call may be registered by pressing the

hall call button

24 or 25 at a landing and thereby closing the circuits to the associated relays. Thus, for example, if an intending passenger at the top floor presses the top floor button 24 he closes contacts S12D in line 202 so that current may flow from an energized control circuit supply line CS through a coil HB of a hall button relay, the contacts of push button 24, lead 26. and an operating coil 812D of the twelfth floor down hall call relay, to the return lead 00. The down hall call relay S12D is thereupon energized and closes its contacts S12D, line 203, to complete a by-pass circuit around the push button 24 and thus maintain the operating coil of the relay energized. A circuit is also completed at this time through lead 27 to the appropriate contacts of the floor selector machines so that a car may answer such call. When the call is answered a circuit is completed through a neutralizing coil of the hall call relay 812D and lead 28 to deenergize the relay. Similar circuits are provided for each of the other floors. For intermediate floors, two such relays are provided, one for up calls and one for down calls.

FIGURE III A bridge circuit for measuring the trafiic demand in the down direction is illustrated in lines 301 to 312 inclusive. This bridge circuit includes a first or balancing arm comprised of parallel resistors R1 to R7 that are introduced into the circuit according to the number of traffic counting relays 536A through G that are in their on 1 Composite relays having armature actuated contacts and ratchet operated contacts.

condition. A second arm of the bridge comprises resistors RX, one for each down hall call relay, that are introduced into the bridge circuit as long as the corresponding down hall call relays are energized. The bridge also comprises ratio arm resistors R8 and R9 shown in

lines

301 and 312. Preferably the resistors R8 and R9 are equal to each other and each is approximately onefifth of one of the resistors RX or R1 through R7. The unbalance in the bridge circuit is detected by a pair of

polarized relays

532 and 534. These relays are connected across the diagonal of the bridge through normally closed contacts 536A through 5366 which, as explained later, momentarily open the detector circuit as a change in the count in the counting relays is made following each detection of an unbalance. The down add detector relay 532 is polarized to be responsive to current flowing from the second arm of the bridge, the hall call resistors RX, through the coil of the relay, the normally closed chain of contacts 536A through G and resistor R8. The down subtract detector relays 534 are polarized to respond to current flowing in the opposite direction. 7

The parallel combination of the hall call resistors RX is shunted by ressitors RY representing load in the down traveling cars as long as the circuits in lines 313 to 319 inclusive are completed. These circuits for the first car are illustrated in lines 313 to 316 and similar circuits for the other cars are indicated in

lines

317, 318 and 319. The resistors RY, each equal in value to a resistor RX, are arranged to be inserted in shunt with the resistors RX whenever the car is in service as indicated by closure of contacts ISa, the car is loaded to a certain degree as in:- dicated by closure of contacts W-l for a 20% load, WZ for a 40% load and W-3 for a 60% load, the car is not at the first or terminal floor as indicated by closure of contacts lFa in line 313, and is conditioned for down travel as indicated by closure of down memory contacts DLa shown in line 313.

In the operation of this circuit, assuming that it is orig inally balanced, the addition or registration of a hall call by adding a resistor RX into the second arm of the bridge results in current flow upwardly through the down add detector relays 532. This relay thereupon closes its contacts and, by means of the circuits shown in FIGS. IV and V, results in the operation of a counting relay which momentarily opens the detector arm of the bridge circuit by opening one of the counting relay contacts and adds another one of the resistors R1 through R7 into the first arm of the bridge. If the addition of the resistors R1 through R7 results in a balancing of the bridge no further action takes place. However, if it is not suflicient to balance the bridge, current again flows through the detector relay 532 to initiate another step. in the counting chain thus adding another resistor to the first arm of the bridge. Likewise, if one or two or more of the hall calls are an swered so that the corresponding resistors RX are cut out of the bridge arm, current flows downwardly through the detector arm of the bridge, through the coils of the down subtract relay 534 thus initiating a subtract action to return one of the counting relays to its off condition thereby removing one of the resistors R1 through R7 from the bridge circuit. This action may be repeated if necessary to secure a balance in the bridge.

The circiuts indicated in lines 317 to 319 correspond, for cars B, C and D, to the circiuts shown in

lines

313 and 316 for car A and act on the down trafiic bridge in the same manner.

An up trafiic measuring bridge is illustrated in lines 320, to 328 and includes some of the circuits shown in lines 313 to 319. This bridge includes a first or balancing arm that includes resistors R13 to R19 that are connected in parallel with each other into the bridge arm according to the number of up trafiic counting relays 535A through G that may then be actuated. The ratio arms for this bridge are provided by resistors R12, line 320, and R20, line 328. A second or measuring arm of the bridge comprises resistors RY and RZ for the various cars that are arranged to be added in to the second or measuring arm as long as the car is conditioned for service as indicated by closure of its in service contacts ISa, is loaded as indicated by closure of contact W-1 for a 20% load, W2 for a 40% load or W-3 for a 60% load, is not at the first floor, and is conditioned for upward travel as indicated by closure of up memory contacts UL, line 315. Additionally, the registration of a car call adds resistor RZ in parallel with resistors RY as a measure of the traflic being served by car A. Similar circuits for cars B, C and D are indicated in lines 317 to 319. These resistors make up the principal portion of the second or measuring arm of the up traflic bridge. In addition resistor R11 and under certain conditions R are included in shunt with these as long as there is an up call registered at the lobby floor as indicated by closure of contacts SIU in line 320. The resistor R10 is shunted around resistor R11 as long as the one car in service relay contacts 471 are closed to indicate a heavier trafiic demand and thus accelerate the starting of additional cars. Up add detector relay 531 and up subtract detector relay 533 are similar in construction to the down add and down subtract

relays

532 and 534 and are sensitive polarized relays equipped with magnetic contacts or magnetic latches to provide reliable contact operation. These relays have reset coils 531R and 533R shown in line 502 for resetting detector relays as an additional counting relay is added or subtracted from the counting relay chain.

FIGURE IV When the up add detector relay 531 operates in response to an increased up traffic demand it closes its contacts 531, line 408, to complete a circuit from the energized control circuit lead CS through an operating coil 531X of an up add auxiliary relay 531X. Similarly, when the down a-dd detector relay 532 operates in response to an increase in down traific demand it closes its contacts 532 in line 421 to energize a down add auxiliary relay 532X. Furthermore, as long as a car is conditioned for upward travel and is not responding to a high call reverse stop it briefly energizes the up add auxiliary relay 531X for each stop unless the system is operating on its down peak program to open contacts 582 in line 409. Thus, the car A circuit is completed at lines 410 and 409 through in service relay contacts IS, door control contacts D0 which are normally closed, first floor relay contacts 1F which are closed and open when the door is fully closed as long as the car is not at the first floor, and normally open brake contacts B that close as long as the car is in motion, normally closed high call reverse contacts HCR, line 409, up memory relay contacts UL and normally close-d down peak relay contacts 582. This circuit is closed momentarily or during the period from the time the doors start to open as the car approaches a landing and the time that the brake relay is released as the car stops at the landing.

This circuit is duplicated in

lines

413, 416 and 419 for each of the cars so that all of their up stops are added into the up trafiic counting relay chain. Similar counting of down stops is provided by circuits including the down memory relay contacts DL, normally closed light trafiic relay contacts 560 and normally closed up peak program timing relay contacts 581 in line 420 to add a count into the down trafiic counting relay chain each time a stop is made. This circuit is only effective during light trafiic conditions since the light traific relay 560, shown at line 524 of FIG, V, is energized to open its contacts at the third level of down traffic demand.

An up subtract relay 533X and a down subtract relay 534X shown in

lines

404 and 403 respectively are normally energized through normally closed

contacts

533 and 534 of the up and down subtract

detector relays

533 and 534. These relays are also energized through

contacts

531X and 532X of the up and down add

relays

531X and 532X to prevent a subtraction in the chain of counting relays while an addition is in progress.

The actual drop-out of the relays 533X and 534K is delayed after the deenergization of their control circuits by means of condensers C1, C2 that are connected to the operating coils through resistor R22 or R24 to provide, for the up subtraction, a delay of four to five seconds, and, for the down subtraction, a delay of two to three seconds; Additionally the up subtract relay 533X is provided with an additional time delay circuit comprising resistor R25 and condenser C3 that is connected into this circuit as long as only one car is in operation as indicated by closure of one car relay contacts 471, line 407.

FIGURE V A chain of counting relays 536A through 5366 are illustrated in lines 509 to 523 of FIG. V. A similar chain of counting relays 535A through 535G, not shown, are employed for counting the up traffic demands. Since the chains are similar only the one for the down traffic is illustrated. Each of the seven relays 536A through 5366 is of a composite construction that includes a ratchet controlled set of contacts that operate from off to on or from on to oif as the operating current in the coil of the relay is cut off and thus alternately assume their contact opening or contact closing positions. In addition, each of these relays includes sets of contacts operated directly by the pawl actuating mechanism each time the coil is energized. Thus, for example, the first down trafiic counting relay 536A has a first set of normally open contacts, line 301, that alternately open and close with successive deenergization of the operating coil. Contacts 536A of the relay 536A shown in line 302 are operated by the pawl actuating mechanism so as to break the detector arm of the bridge circuit each time the operating coil 536A is energized. Likewise, contacts 536A in line 504 are closed each time the operating coil is energized. The remaining contacts, shown in

lines

509, 510, 601 and 625, are ratchet operated. With this understanding of the operation of the counting relays 536 the operation of the chain of relays may be traced on the diagram in FIG. V.

Assuming that initially all of the counting relays are in their off position the first operation of the down add counting relay 532X acts to close its contacts in line 508 so that current may fiow from the energized supply lead CS through the now closed contacts 532X, through add lead 30, normally closed contacts 53A in line 509 to the operating coil 536A. As long as this current flows the contacts 536A in line 302 are opened and those in line 504 are closed. Closure of the contacts 536A in line 504 energizes reset

coils

532R and 534R of the down add and down subtract detector relays to return these relays to their normal condition. Returning the down add detector relay 532 to its normal position opens its contacts in line 421 to deenergize the down add auxiliary relay 532X thereby breaking the circuit in line 508 to the 536A operating coil. This coil thereupon releases and the pawl advances the ratchet mechanism to the next position thereby closing contacts 536A,

line

301, and 536A, in line 510, and also opening the contacts 536A in line 509. Closure of these contacts in line 301 introduces the resistor R1 into the balancing arm of the down trafiic sensing bridge while closure of contacts 536A, in line 510 in the series at the left side of the diagram, prepares a circuit for the operating coil of the second counting relay 536B at the same time that it prepares a subtracting circuit 31 through the normally open contacts 536A shown near the center of the diagram. Opening of the normally closed contacts 536A in line 509 opens the add operating circuit to the counting relay 536A.

With the contacts 532X, line 508, open and the normally closed contacts 536A, line 509, also open current flows through resistors R36, R37 and coil 536A to energize a low current indicator lamp 32 to indicate that a first unit or first level of down traffic is in effect. If the insertion of resistor R1 in the down trafiic measuring bridge circuit is insufficient to balance the bridge the down add detector relay 532 again closes its contacts to energize the down add auxiliary relay 532X which com pletes a circuit from the lead CS through the now closed contacts 536A in lead 30, and normally closed contacts 536B, line 511, to the operating coil of the second counting relay 5368. This relay immediately cocks its ratchet mechanism and at the same time opens its contacts 53613 in line 303 to open the detector circuit of the bridge at the same time that it closes its contacts 53513 in line 505 to energize the reset coils 532R and 534R of the detector relays. As the detector relay 532 is reset it deenergizes the auxiliary relay to open its contacts 532X, line 508, and thus deenergize the now energized coil 536B. Its ratchet then closes its normally open contacts 5353,

lines

302 and 512, at the same time that it opens its normally closed contacts in line 511 to break the circuit to its coil 536B and, at the same time, in line 512 break the subtract circuit ,34, leading up the center of the diagram, to the coil 536A of the first counting relay 536A. This adding operation of additional relays 536 is repeated until the bridge shown in the top of FIG. III is balanced. This may result in the operation of several or all of the counting relays 536A through 5366.

As the calls are answered the down hall call relays are deenergized and thus remove resistors RX from the measuring arm of the bridge. Also as loaded cars arrive at the first floor resistors RY are disconnected from the measuring arm of the bridge. If an equivalent number of new down hall calls are not registered the bridge is then unbalanced in the opposite direction from the first unbalance. The bridge is rebalanced by a subtraction operation in the chain of counting relays to remove an equivalent number of resistors from the balancing arm of the bridge. This substracting operation begins with energization of the polarized down subtract detector relay 534, line 310, which, when actuated, opens its contacts 534 in line 403 to break the circuit to the down subtract auxiliary relay 534X. When this relay drops out following a time delay of two to three seconds provided by condenser Cl it closes its normally closed contacts 534X in line 522 to complete a subtracting circuit from the energized line CS through a lead in line 522 including the now closed contacts 534X and thence up through a subtracting lead 31 in the center of the diagram including the normally closed

contacts

536G, 536F, etc, of any non-operated or off counting relays and thence through the normally open but now closed contacts 536 to the right of lead 31 of the highest order counting relay that is on the on condition. Thus, assuming that four levels of down traffic have open registered to balance the bridge circuit resulting in operation of relays 536A through 536D to the on conditions the subtracting pulse is fed through the normally

closed contact

536G, 536F and 536E, in

lines

522, 520 and 518 and thence through the normally open contacts 536D to the operating coil 536D. This provides a second energization of the operating coil of this relay so that it cocks its ratchet mechanism and at the same time opens its contacts 536D in the detector diagonal of the bridge circuit at the same time that it closes its contacts similar to those in line 565 to energize the reset coils 532, 534. The reset coil 534 immediately resets the down detector subtract relay 534 so that it again energizes its auxiliary relay 534X to open the substract circuit at line 522.

As the counting relay 536D is deenergized by the opening of the contacts 534X in line 522 its pawl and ratchet moves its contacts to the positions shown thereby taking the resistor R4 out of the balancing arm of the bridge as well as preparing the subtracting circuit to the next lower .trafiic level counting relay 536C. This action may be repeated with the counting relays 536C, 536B and 536A to again bring the bridge into a balanced condition.

Since the operating coils of the counting relays 536A through 535G are heavy duty coils on account of the ratchet mechanism,

rectifiers

33 and 34 are connected from the add lead 30 and the subtract lead 31, energized through

contacts

532X and 534X, to the grounded lead 60 to absorb the inductive voltage surge as these contacts open to deenergize the operating coils of the relays.

A light traflic relay 560 shown in line 524 is arranged to be energized when the counting relay chain reaches a third level as indicated by closure of contacts 5360, line 524. This relay then seals itself in through counting chain contacts 536B of a second level relay and its own contacts 560 so that the relay remains energized until the counting chain returns to the condition with only one counting relay in its on position. The dropout of the low trafiic relay 560 is delayed by a timing condenser C6 connected in parallel with its operating coil. A resistor R45 is inserted in series with the condenser to limit the peak charging current and thus protect the contacts 536C from the initial surge of current flowing to the condenser when the contacts make.

The two chains of counting relays, the series 535A through G and the series 536A through G, provide, according to the number of counting relays energized in each series, a quantitative indication of the trafiic demand then existing in the system. This quantitative indication of the traffic demand in the up and down directions may be employed to institute specific programs of operation or control a number of functions in the supervisory control of the elevator system, For example, an increase in traffic level may call for the starting of idle motor generator sets and elevators to meet an increased demand. The quantitative traffic demand indication may also be employed to regulate or adjust the dispatching timing intervals at each of the terminals of the system so as to keep the cars properly spaced to give the best service.

Of the many types of programs that may be employed in the operation of an automatic elevator system the up peak program and the down peak program are two that are employed in practically any installation. In an ofiice building, for example, the up peak program occurs at the beginning of the business day when the building occupants are coming to work. A similar situation occurs at the end of the lunch period when those tenants who have left the building for lunch are returning to their offices. Down peak trafiic patterns occur at the beginning of the lunch hour in some types of buildings and again at the close of the business day when the ofiices are closing and the occupants are leaving the building. The quantitative indication of traffic demand afiorded by the bridge circuits responsive to various indications of traflic may be employed in the circuits shown in FIG. V to set. up the up peak or down peak programs and hold such programs in effect until the traffic conditions calling for such programs have subsided.

FIGURE VI In the circuits shown in FIG. VI a timer supply lead 35 is energized from the control circuit power lead CS as long as three or four cars are in operation as indicated by closure of three car or four

car relays

473 or 474 having contacts shown at

lines

602 and 604. This lead 35 provides direct current power for the circuit of the up peak timer relay 581 shown in line 603 and up peak cancel timer 583 shown in line 610 and, through normally closed contacts of a no-call relay 430, to down peak timer 582 shown in line 617 as well as a down peak cancel timer 584 shown in line 622. The up peak cancel timer 583 has normally closed contacts 583 in line 604 which permit current to flow from the lead 35 through an operating coil 581 of the up peak timer and then through a grid controlled glow discharge tube 36 whenever the potential on its grid 37 exceeds a certain critical positive potential. The up peak timer 581 may also be energized immediately through series connected normally closed contacts 9 536A of the first level down traific counting relay 536A and normally open contacts 5356 of the seventh level up trafiic counting relay 535G shown in line 601 in the event there is no down trafiic demand and a maximum amount of up traffic demand. 1

The grid controlled tube 36 is fired to energize the up peak timer relay 581 after time delays depending upon the level of up traffic demand coupled with a lesser level of down traflic demand. Thus, if there is less than a fourth level of down trafiic demand such that contacts 536D are closed at line 607 and there is at the same time at least a fourth level up traffic demand as indicated by closure of contacts 535D voltage is applied through a voltage divider comprising resistors R62 and R63.

This voltage applied across the resistor R59 and condenser C9 charges the condenser to the firing voltage of the tube 36 in approximately ten seconds. This timing may be varied according to the demands of a particular installation. When this relay is energized by current flow through the tube 36 it closes its contacts in line 602 to provide a by-pass circuit through resistor R57 around the tube 36 thus lowering the plate voltage below the ex tinction potential to deionize the tube. It also closes its contacts 581 in line 607 to discharge the timing condenser C9 through resistor R61 thereby preparing the circuit for a full timing interval the next time the circuit is completed for timing.

If during this timing operation controlled by resistors R62 and R63 the down traflic subsides to release counting relays 536C and the up trai'fic demand increases such that the next trafiic counting relays 53513 is actuated to its on position it closes its contacts 535E, line 606 to shunt resistor R58 around resistor R62 thus raising the voltage on the lead 38 to accelerate the timing operation. Likewise, if the up traffic demand increases to the point where the sixth traffic level relay 535F is actuated to its on position and the down traflic subsides the maximum voltage is applied to the lead 38 resulting in a minimum time interval for the timing out of the up peak timer and energizing its relay 581.

In ordinary operation the up peak timer is deenergized after the up peak trafiic subsides. In some arrangements certain operating features are common to both up peak and down peak operation. In such cases it is desirable to maintain the up peak relay energized during down peak operation. If the up trafiic subsides in the absence of down tratlic the up peak cancel timer acts to deenergize the up peak timer 581. The circuit for the up peak cancel timer 583, is prepared when the up peak timer 581 closes its contacts 581, line 610. This applies plate potential to a second grid controlled cold cathode gas discharge tube 39 which fires to energize the relay 583 whenever the potential on its grid 40 exceeds a critical positive voltage. As long as at least a fourth level of up traffic demand is registered by the up trafiic counting relays 535,

contacts

535A, 5358 and 535C in

lines

613, 612 and 611 are open so that the grid 40 of the tube is held at ground potential through resistors R69, for limiting grid current, R68 for controlling the charging current to condenser C10, and R71 serving as part of a voltage divider that includes resistors R65, 66 and 67 for determining the timing interval for this circuit.

-As the up traffic level subsides and the bridge circuit follows the decrease the counting relay 535C is returned to its off condition. This relay, by closing its normally closed contacts 535C in line 611 completes a circuit through resistor R65 to a junction lead 41 thereby applying sufiicient voltage to lead 41 to allow the condenser C to be charged slowly and after an appreciable time delay of approximately two minutes energize the up peak cancel timer 583. This relay then closes its contacts in line 609 to by-pass the tube 39 and thus deionize it and at the same time opens its contacts in line 604 to break the circuit to the up peak timer 581. The up peak timer then drops out unless there is down traffic to hold light down traflic relay 560 contacts closed in line 602 and no motor generator set is being shutdown to open normally closed contacts 517. In the event the up trafiic demand subsides rapidly the up traffic counting bridge circuit subtracts the next counting relays from the up trafiic counting chain of relays 535. These

relays

5358 and 535A then close their contacts to shunt resistors R66 and R67 in parallel with resistor R to accelerate the timing out of the up peak cancel timer 583.

Similar circuits for the down peak timer 582 and down peak cancel timer 584 are prepared for operation as long as there is at least one hall call so that normally closed contacts 430 of a no hall call relay are closed at line 615 to connect the lead 35 to a continuing lead 42. These contacts thus insure that the down peak timers cannot be energized unless there is at least one down hall call.

A down peak timer 582 to institute a program suitable for down peak traffic is prepared for operation as long as the down peak cancel timer 584 is deenergized to close its contacts 584 in line 617. This down peak timer 582 can be energized immediately in the event there is a maximum amount of down trafiic demand and no up tralfic demand so that up traific counting relay 535A is deenergized while down counting tratfic relay 536G is energized and thus closes the circuit in line 615. The

down peak timer relay 582 may be energized after time delays by circuits in lines 618 to 621 that act to apply sufficient potential to a lead 43 so that it may, through resistor R74, charge condenser C11 to a potential such that a grid 44 of a grid control gas discharge tube 46 may fire and thus energize the relay. If the down tratfic demand reaches the fourth level so that the fourth counting relay 536D is moved to its on condition it closes its contacts in line 620 to energize the lead 43 through resistor R77. The current flowing through this resistor also flows through resistor R78, the two resistors forming a voltage divider such that the potential of lead 43 is just suificient to charge the condenser C11 above the break down or firing potential of the tube 46. Time delay in this case is a maximum and may be in the order of ten seconds. If the down trafiic demand increases to a level such that the fifth down traffic counting relay 536E is energized and the up tratfic has subsided to a point where the up counting relay 535C has been actuated to its off position the timing of the down peak timer may be accelerated by current flowing through resistor R75 in parallel with R77 thus raising the potential on the lead 43 and accelerating the charging of the timing condenser C11. A still shorter timing interval occurs if the down traffic counting relay 536F is energized and the up tratfic counting relay 535B is in its otf position. This indicates a large unbalance in trafiic demands in favor of down traflic thus calling for a relatively quick changing of the system to a down peak program.

Once the down peak timer relay 582 is energized it closes its contacts in line 616 to complete a by-pass circuit around the tube 46 and at the same time closes its contacts in line 620 to discharge the timing condenser C11. This relay then remains energized through its sealing circuit until either the down peak cancel timer 584 times out to open its contacts 584 in line 617 or there is a momentary or continued interval during which there are no hall calls such that the relay 430 is energized or there are less than three cars in operation as indicated by the opening of

relay contacts

473 and 474 to deenergize lead 35.

The down peak cancel timer 584, which was prepared for operation when the down peak timer 582 was energized to close its contacts in line 622, is energized following a time interval whichvaries according to the actual down trafiic demand. Thus, if the down traffic subsides to a level where the third level counting relay 536C is moved to its 0175 condition current flows through resistors R79 and R84, acting as a voltage divider, to

apply a potential to lead 47 sufficiently positive so that the condenser C12 may, in a time interval of approximately thirty seconds, charge to a potential sufficient to cause break down of the glow discharge tube 43 to energize the relay 584. The timing out of the down peak cancel timer 584 may be accelerated if the down traflic demands subside to the point where the second or in some cases the first down traffic counting relays 536B and 536A are moved to their off condition. As these relays move to their off condition a resistor R80 is first connected in shunt with resistor R79 to raise the potential on the lead 47 thus accelerate the charging of the condenser C12. Likewise, when the counting relay 1536A is moved to its off condition it closes its contacts 536A in line 625 to apply a maximum potential to lead 47 and thus provide a minimum time delay. When this cancel relay 584 is energized it opens its contacts &4 in line 617 to deenergize the down peak timer 582.. This relay then opens its contacts in line 622 to deenergize the relay 584 and at the same time close its contacts in line 625 to discharge the condenser C12.

The up peak and down peak timer relays 581 and 582 respectively may be arranged to set up appropriate circuits for the supervisory control of the elevator system such as instituting high call reverse, changing dispatching time intervals at the terminals or eliminating such intervals, or adding an additional motor generator set and car to service, or for initiating other changes in the supervisory control so as to best meet the trafiic pattern then existing in the system.

The just described operation of up peak and down peak program timers are examples of supervisory control elements that may advantageously employ quantitative information of traffic demands and adjust the program of operation accordingly.

The trafiic measuring bridge circuits have the advantage of continuously monitoring the trafiic demand and may, therefore, quickly call for adjustments in the operating program to meet the demands.

Since in this type of system it is always preferable to have a slight excess of service available the bridge detector and counting relay systems are arranged to be instantly responsive to bridge unbalances indicating increases in trafiic demand. For the same reason the subtract relays are provided with time delay characteristics to delay for at least a few seconds any subtract operations. This time delay is particularly effective during up trafiic patterns when the cars often are required to make many stops while discharging a load of passengers. Since an up add count is registered for each stop regardless of balance in the up trafiic bridge the bridge becomes unbalanced and initiates subtract operations. By delaying the subtract operations the counting relays remember the stops and thus reflect a more accurate indication of the up traffic demand.

During light down traffic, stops are also counted so that the down traflic counting relays may indicate a slightly heavier traffic than actually exists. This stop counting thus has the effect of biasing the control system toward the heavier traffic programs.

The measurement of down traffic is based primarily on the number of unanswered down hall calls. However, to minimize hunting and unnecessary changes of program, the loads in the cars are also included in the measurement. A twenty percent load is preferably made equivalent to one hall call. Thus, in an average system, if two or three down passengers enter the car a resistor RY is substituted for the resistor RX, which was taken from the bridge circuit as the hall call was answered, and the bridge balance is not changed.

In the up trafiic bridge the measurement depends primarily on the loads in the cars. This is supplemented by the existence of up calls at the terminal and a car call registered in the car. Since each twenty percent of load counts as one unit, and a car call counts as a half unit or one unit, depending on the system, a fully loaded car leaving the terminal advances the bridge and counting relays to the fourth level. Other cars may still be partly loaded so it is thus possible to register with two cars a peak up traffic demand. Such a situation existing for a few seconds would throw the system into up peak operation.

The bridge circuits thus measure the traffic demands in terms of the number of unanswered hall calls and the amount of load in the cars. The counting chains of relays for rebalancing the bridge circuits are, under certain conditions, further biased toward heavy traffic indications by counting the number of stops performed by the cars.

These circuits thus provide a continuous indication of traffic level and provide means for instituting appropriate programs of operation to meet the trafi'ic patterns as they occur.

Various modifications may be made in the various circuits described for controlling the operation of a bank of elevators according to the observed traffic demand and instituting programs of operation in accordance with such demand without departing from the spirit and scope of the invention.

Having described the invention, I claim:

1. In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response to demands for service, means for measuring traflic demand'by measuring the number of unanswered down hall calls, the loads in the cars during up trips, and the loads in the cars during down trips, and means for correlating such measurements to indicate heavy up traffic and heavy down traffic and means for instituting up peak and down peak programs of operation to serve the traffic pattern then indicated by such measurement correlation.

2. In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response to demands for service, means for measuring the number of unanswered down hall calls and the loads in down traveling cars, and means for instituting a down peak program of operation to serve a down traffic when such measurement attains a certain level.

3. In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response to demands for service, means for measuring such demands for service that includes a bridge circuit one arm of which comprises elements representing unanswered hall calls and a balancing arm of which comprises balancing elements representing levels of traffic demand, means for balancing the bridge by altering the effective number of balancing elements included in such bridge circuit, and means responsive to the number of said balancing elements included in the bridge for modifying the operation of said elevators.

4. In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response to demands for service, means for measuring such demands for service that includes a bridge circuit one arm of which comprises a resistor for each unanswered hall call and each increment of load in down traveling cars, and a balancing arm which comprises balancing resistors corresponding in number to traffic level being indicated, means for varying the number of balancing resistors included in the circuit to balance said bridge circuit, and means responsive to the number of balancing resistors in said bridge circuit adapted to modify the operating program of the elevator system.

5. In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response to demands for service, means for registering such demands for service, means for measuring such demands for service that includes a bridge circuit one arm of which comprises a plurality of elements one for each unanswered hall call and one for each increment of load in down traveling cars and a balancing arm of which comprises a plurality of balancing elements, a detector sensitive to bridge unbalance, a series of counting means that are successively energized and deenergized in response to said detector, said counting means serving to vary the number of balancing elements included in the bridge circuit, and means responsive to the counting means for modifying the operating program of said elevators.

6.- In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response to demands for service, means for registering demands for service, means for measuring the demand for service comprising a bridge circuit one arm of which comprises an element for each increment of load in up traveling cars and a balancing arm of which comprises a plurality of balancing elements, a chain of traflic counting means adapted to vary the number of balancing elements included in said bridge arm for balancing said bridge, a detector for said bridge adapted to successively energize said counting means in response to unbalance in the bridge circuit to vary the number of balancing elements in the circuit, and means responsive to said counting means for modifying the program of operation of said elevators.

7. In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response todemands for service, means for registering demands for service, means for measuring the demand for service comprising a bridge circuit one arm of which comprises an element for each increment of load in up traveling cars and a balancing arm of which comprises a plurality of balancing elements, a chain of counting means adapted to vary the number of balancing elements included in the bridge circuit, a detector for the bridge circuit adapted to energize the counting means in a direction to balance the bridge circuit, means responsive to up stops of the elevators for energizing the counting means to vary the number balancing elements in the bridge circuit, and means responsive to the counting means for varying the program of operationof the elevator system.

8. In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response to demands for service, means for registering demands for service, means for measuring the demand for service comprising a bridge circuit one arm of which comprises a resistor for each unanswered hall call and certain increments of load in down traveling cars and a balancing arm of which comprises a variable number of resistors, counting means arranged to vary the number of resistors in said balancing arm, a detector responsive to an unbalance in said bridge circuit in a first direction adapted to immediately add counts in said counting means and responsive to unbalance in a reverse direction for subtracting counts at timed intervals, and means responsive to the counting means for modifying the program of operation of the system of elevators.

9. In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response to demands for service, means for registering demands for service, means for measuring the demand for service comprising a bridge circuit one arm of which comprises an element for each demand for service and for each of certain increments of load in the cars, and a balancing arm of which comprises a plurality of balancing elements, means for balancing the bridge including a detector and counting means for immediately successively adding said balancing elements into said balancing arm to correct an unbalance in a first direction and for successively subtracting balancing elements at timed intervals to correct an unbalance in a reverse direction, and means responsive to said counting means for modifying the pro-gram of operation to meet the measured traflic demand.

10. In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response to demands for service, means for measuring such demands for service that includes a bridge circuit one arm of which comprises eiements representing car loading and unanswered hall calls and one arm of which comprises balancing elements representing levels of traflic demand, means for balancing the bridge by altering the effective number of balancing elements included in the bridge circuit, and timing means having time delays that vary with the number of balancing elements then included in the bridge circuit for instituting and canceling certain programs of operation in accordance with the traffic demands represented by the balancing elements included in the bridge circuit.

11. In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response to demands for service, means for measuring such demands for service that includes a first bridge circuit having a first arm comprising elements representing unanswered hall calls and increments of load in down traveling cars and a second arm comprising balancing elements representing levels of traffic demand, means for balancing the bridge by altering the effective nurnber of balancing elements included in the circuit, a second bridge circuit having a first arm comprising elements representing loads in up traveling cars and a second arm comprising balancing ele. ments representing levels of traflic demand, means for balancing the second bridge by altering the number of balancing elements in the second arm, circuits for instituting and canceling a program of operation, said circuits being connected to the balancing means of said bridge circuits and responsive to the level of traflic demand indicated in each bridge circuit.

12. An elevator system according to claim 11 in which the circuits for instituting and canceling a program of operation include timing means the timing intervals of which vary according to the level of tratlic demand indicated by the bridge circuits.

13. An elevator system according to claim 11 in which the circuits for canceling a program of operation responds to a lower level of tratfic demand than the circuit for instituting such program of operation.

14. An elevator system according to claim 11 in which the circuit for instituting a program of operation has a time delay that varies with the level of trafiic demand and is short when compared to the time delay of a circuit for canceling the program of operation.

15. In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response to demands for service, means for quantitatively measuring such demands for service in each of two directions of travel, means responsive to the measuring means for instituting a peak program of operation in response to a predetermined excess of demand in one direction over the demand in the other direction, said instituting means being instantly responsive to a certain excess in demand and being responsive to a lesser excess of demand maintained over a time interval.

16. In an elevator system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for operating said cars in response to demands for service, means for quantitatively measuring such demands for service in each of two directions of travel, means responsive to the measuring means for instituting a peak program of operation in response to a predetermined excess of demand in one direction, said instituting means being responsive to certain levels of excess of demand maintained for certain intervals of time, and means for canceling said peak programs in response to a continued reduction in such excess of demand.

17. In an elevator system comprising a plurality of cars serving a plurality of landings, means for measuring traffic conditions in said system for a given direction of travel, means for altering the operating pattern of said system to provide a preponderance of service in said given direction of travel, a timer for actuating said pattern altering means to provide for preponderant service in said given direction upon expiration of an interval of at least a given level of traffic conditions for said given direction, and means to vary said interval inversely with said traflic condition level.

18. In an elevator system comprising a plurality of cars serving a plurality of landings, means for measuring trafiic conditions in said system for a given direction of travel, means for altering the operating pattern of said system to provide a preponderance of service in said given direction of travel, a timer for actuating said pattern altering means to provide for preponderant service in said given direction upon expiration of an interval of at least a predetermined level of traffic condition for said given direction, means to vary said interval inversely with said traflic condition level, and means to actuate said pattern altering means to provide for preponderant service in said given direction upon the sensing of a second predetermined level of said trafiic condition for said given direction.

19. In an elevator system comprising a plurality of cars serving a plurality of landings, means for measuring traffic conditions in said system for a given direction of travel, means for measuring traflic conditions in said system for a direction of travel opposite said given direction, means for altering the operating pattern of said system to provide a preponderance of service in said given direction of travel, a timer for actuating said pattern altering means for providing a preponderance of service in said given direction upon sensing at least a predetermined preponderance of the traffic condition level in said given direction over that condition in said opposite direction for a given interval, and means to vary said interval init; versely with the degree of preponderance of traffic conditions in said given direction.

20. In an elevator system comprising a plurality of cars serving a plurality of landings, means for measuring traffic conditions in said system for a given direction of travel, means for measuring trafiic conditions in said sysem for a direction of travel opposite said given direction, means for altering the operating pattern of said system to provide a preponderance of service in said given direction of travel, and a timer for actuating said pattern altering means for providing a preponderance of service in said given direction upon sensing at least a predetermined preponderance of the trafiic condition level in said given direction over that condition in said opposite diection for a given interval.

21. A combination according to claim 20 including means for actuating said pattern altering means for providing a preponderance of service in said given direction upon sensing of a given second level of preponderance of tratfic conditions in said given direction over traflic conditions in said opposite direction.

22. In an elevator system comprising a plurality of cars serving a plurality of landings, means for establishing an operating pattern in the system for providing a preponderance of service in a given direction, means for sensing the level of traffic conditions in said system for said given direction, a timer for rendering said pattern establishing means ineffective a predetermined interval following the decline of the level of traflic conditions for said given direction below a predetermined level, and means to reduce said interval as a function of the reduction of the level of traffic conditions for said given direction.

References Cited by the Examiner UNITED STATES PATENTS 2,581,245 l/l952 Eames 187-29 2,827,980 3/1958 Suzzo et al. 18729 ORIS L. RADER, Primary Examiner.

MILTON O. HIRSHFIELD, Examiner.

G. G. JENSEN, B. DOBECK, Assistant Examiners.

Claims

1. IN AN ELEVATOR SYSTEM, IN COMBINATION, A PLURALITY OF ELEVATOR CARS ARRANGED TO SERVE A PLURALITY OF FLOORS, MEANS FOR OPERATING SAID CARS IN RESPONSE TO DEMANDS FOR SERVICE, MEANS FOR MEASURING TRAFFIC DEMAND BY MEASURING THE NUMBER OF UNANSWERED DOWN HALL CALLS, THE LOADS IN THE CARS DURING UP TRIPS, AND THE LOADS IN THE CARS DURING DOWN TRIPS, AND MEANS FOR CORRELATING SUCH MEASUREMENTS TO INDICATE HEAVY UP TRAFFIC AND HEAVY DOWN TRAFFIC AND MEANS FOR INSTITUTING UP PEAK AND DOWN PEAK PROGRAMS OF OPERATION TO SERVE THE TRAFFIC PATTERN THEN INDICATED BY SUCH MEASUREMENT CORRELATION.