US2827982A - Elevator system having plural modes of operation - Google Patents

Description

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March 25, 1958 D. SANTlNl ETAL 2,827,982

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United States Patent O ELEVATQR SYS HAV N LURALMQDES; F OPERATION DaniloSantini, Tenafly, and John Suozzo, Paramus, N: 1;, assignors to. Westinghouse Electric Corporation, East Pittsburgh, Pa., acorporation of Pennsylvania Application October 31,1955, Serial No. 5433732 13- Claims. (CL. 187-29) cal ofiice building an off-hours period may occur during the night; During this period the demand for elevator service is intermittent and light,

At the start ofa business day and immediatelyafter the lunch hour, up-pcak periods are encountered. Duringan up-peals period a large number of intending passengers desire to be transported from the lower dispatching floor of the system to higher floors.

At the start of the lunch hour and at the close; of the business, day, down-peak periods occur. Durings uch :a period large numbers ofintending: passengers desire service; from the higher floors of the office building to the ground floor of the building.

During the remainder of the business day, oil-peak periods are present. During an oil-peak period, intending passengers desiring to travel in the up dircction and intending passengers desiring to travel in the down direotion are present.

In order to provide etficient service for each of" the aforesaid periods, the elevator system may be conditioned o Provide different modes of op r ion- Such mode of operation, are now well known in the art As an or;- a p e, in an -p k p r od th ele at ca may b dispatching successively at intervals from upper and lower sp g floors and m y per t onv t rough t ip between such; disp tc n floo s Dur g a own-peak period each of the elevator cars may be conditioned when traveling in an up direction to reverse at the highest call for service which such elevator car may answer. In addition, the elevator cars may be dispatched promptly from the lower dispatching floor,

The transfer of an elevator system from one mode of operation to another mode of operation may be elfected m a ly or au omati l y- F t matic ranster i has been proposed that the elevator system be controlled by a time. clock which selects difierent modes of operation at different times of a day. In a preferred embodiment of the invention the transfer between modes of operation is dependent on a traffic condition.

El vator ys ms h e des gn for per tion i attendants in the cars and operation without attendants in the cars. Although the present invention is applicable to either of these types of elevator systems, it is particuady s i a e. for systems d i ed fo automat operation without car attendants and will be described with reference to such a system.

In accordance with the invention, the elevator system has a first response to a first trafiic condition for transterring the. levat sy m fr m. rs to a we mod of operation. However, in the presence of a second trafiic condition, the elevator systemis not subject to the 2; first response, but instead has a second response to the firsttratfic condition for transferring the system between the modes of. operation.

In a specific embodiment of the invention, an elevator system may be arranged to provide a substantially balanced': service. during an. off-peak period. If' a certain number-.01: quota ofdown calls are registered from the floors of the building served; by the elevator system, the system is transferredi'toa mode of operation particularly suitable fora down-peak period. However, if a demand for service in: the. up directionexists, the number or quota of down calls necessary to transfer the system to a downpeakmode oi operation isincreased. The demand for service inv the. up. direction maybe measured; by measuring thenumber of stops made by the elevator cars while they are set for; travel in the up direction.

The response of the elevatorsystem to the quota of downealls also may becontrolled byother trafiic conditions or e am e. f pr de e mined nu of elevator cars set for travel in the up direction at the lower dispatching floor are loaded sutficiently to indicate that the cars may be required to make stops while set for up travel, such loading may prevent the transfer olj the system to a down-peak mode of operation despite the pres ence of the required number or quota of; registered down calls.

The transfer of the elevator system to a differentmode of operation also may modify the dispatching of the elevator cars from a dispatching lloor. Thus, during olipeak operation elevator cars may be dispatched su'coes sively at intervals from the lower dispatohing floor. However, when the system is transferred to a down-peak mode of operation all elevator cars presentat the lower dispatching floor in excess of a predetermined number may be dispatched promptly from the dispatching floor. The remainder of the elevator cars may be held for .a reasonable time at the dispatching lloor to provide a reasonable amount of service for intending passengers at the dispatching floor who desire to travel to ahigher floor.

It is, therefore, an object of the invention to provide an elevator system wherein a traffic condition determines the transfer of the system between different modes of p t on. nd herein he esp s o e. System ath first traflic condition is dependent on a second traffic condition.

It is another object of the invention to provide an elevator system which transfers from a first to a second mode of operation in response t h occurrence of a predetermined quota of registered calls and wherein the value of the quota is dependent on a trailic condition.

It is another object of the invention to provide an elevator system which transfers from a first to a second mode of operation in response to the occurrence ofa predetermined quota of registered calls and wherein the value of the quota is dependent on a traflic condition in the up direction.

It is also an object of the invention to provide an e to sy tem he e h t ans er Of the s stem r a first to a second mode of operation is accompanied by a modi t on t the is atch o h v o cars trmn a disp chi oor- It is a further object of the invention to provide an elevator system set forth in the preceding paragraph wherein the modification in the dispatch of the elevator cars conditions all elevator cars present at the dispatching floor in excess of a predetermined number to be dispatched promptly from the dispatching floor, the remainder of the elevator cars being dispatched with time de a om the. dispatching fi o Other objects of the invention will be apparent from anemone the following description taken in connection with the accompanying drawings, in which:

Figure 1 is a schematic view with parts in elevation of an elevator system which may embody the invention;

Figs. 2 to 5 are schematic views including circuits in straight line form of a control system embodying the invention; and

Figs. 2A to 5A are key representations of electromagnetic relays and switches employed in the circuits of Figs. 2 to 5 respectively. If Figs. 2 to 5 are horizontally aligned respectively with Figs. 2A to 5A, it will be found that coils and contacts of the switches and relays appearing in the key representations are horizontally aligned with the corresponding coils and contacts in these circuits.

In order to simplify the presentation of the invention, the invention will be applied to the elevator system disclosed in the Suozzo Patent 2,695,077 which issued November 23, 1954. Unless otherwise indicated, the con ventions employed in this patent will be herein followed. The system includes, in part, the following apparatus:

APPARATUS SPECIFIC TO CAR A Vspeed relay Uup switch M-car-running relay D--down switch Gholding relay J-reversing relay E-slowdown inductor relay F-stopping inductor relay Wup-preference relay Xdown-preference relay 70T-timing relay Hcar-call-above relay TT-car-call stopping relay K-floor-ctll stopping relay SEE-main starting relay Tauxiliary stopping relay Z-expediting relay Lcarposition relay N-loading relay Sauxiliary starting relay 57Tsecond timing relay APPARATUS COMMON TO ALL CARS Figure 1 Fig. 1 is identical with Fig. 1 of the aforesaid Suozzo patent with the exception of the addition of load weighing platforms in the elevator cars. Thus, the elevator car A is provided with a spring-biased platform PM which operates a load switch LWL. The switch LWL remains closed until the elevator car is loaded above a predetermined weight, such as 40% of the rated capacity of the elevator car, whereupon the switch LWL opens. Also, contact segments and brushes may be added to the floor selectors 19 and B19 as indicated below.

Fig. 2

Fig. 2 is identical with 2 of the aforesaid Suozzo patent except for the addition of three contacts. Make contacts J1 of a reversing relay J are connected in part patent.

lel with the contacts TTl, T1, K1 and G1. Closure of the make contacts J1 while the elevator car A is traveling in the up direction conditions the elevator car to stop at the next door approached by the elevator car.

Break contacts J2 of the reversing relay I and make contacts M8 of the car-running relay M are connected in parallel for the purpose of further controlling the energization of the tip-preference relay W. When the contacts J1 of the reversing relay close to initiate the stopping of the elevator car at the next floor approached by the elevator car, the break contacts J2 open. As the car comes to a stop, the make contacts MS of the carrunning relay open to interrupt the energization of the up-preference relay W. The deenergization of the uppreference relay W conditions the elevator car A for down travel in the manner set forth in the aforesaid Suozzo patent. The make contacts M8 are operated by the carrunning relay M of the aforesaid Suozzo patent.

Fig. 3

Fig. 3 of the present patent application may be identical to Fig. 3 of the aforesaid Suozzo patent except that a down floor call push button 5D for the fifth floor is illustrated for controlling the energization of the down floor-call storing relay SDR. This relay has holding make contacts 5D! in parallel with the push button 5D and has a canceling coil SDRN associated with a contact segment g5 for the fifth floor. The operation of the canceling coil will be understood from the operation ,of the canceling coils associated with the other floorcall storing relays of the Suozzo patent. It will be understood that when a fioor call is registered by an intending passenger at the fifth floor the floor-call storing relay 5DR is energized. The first elevator car to reach the fifthfloor then completes an energizing circuit for the canceling coil SDRN to reset the floor-call storing relay 5DR. As pointed out below certain of the relays may have additional contacts not employed in the Suozzo For present purposes it will be assumed that the emergency dispatching device of the Suozzo patent is not here employed. For this reason the present Fig. 3 omits the contracts EMl and STl shown in the Suozzo patent.

Fig. 4

The left-hand column of Fig. 4- may be identical with the left-hand column of Fig. 4 of the Suozzo patent except for the addition of make contacts DB2 of the instant dispatch relay and make contacts RGPS of the auxiliary down-peak relay. These contacts are connected in series across the contacts 77. Consequently, when the contacts IDB2 and ROPS are closed, they eliminate the dispatching interval otherwise provided by the contacts 77.

For present purposes it will be assumed that the relay P and the fuse 70F of the Suozzo patent are not here employed. Therefore, the present Fig. 4 omits the contacts P1 and the conductors 69 and 70 of the Suozzo patent are here shown as extensions of the buses L- and L+.

The right-hand column of Fig. 4 shows the quota relay QRL, the down-peak relay RDP, the auxiliary downpeak relay ROP, the timing relay RPT and the high-call relay HC.

The quota relay QRL picks up when a number of down floor calls are registered sufficient to justify the transfer of the elevator system from an off-peak mode of operation to a down-peak mode of operation. The energization of this relay is controlled by a control device such as a tube TU which may be of any suitable type such as a thyratron or a high vacuum tube. For present purposes, itwill be assumed that the tube TU is a hot-cathode high-vacuum triode having an anode TUA, a grid TUG and a cathode TUC. The relay QRL is connected across the anode and cathode of the tube through the secondary winding of a transformer TR. The primary winding of the. transiormer. may, be. connected, to a suitable source of alternatingrcurrent: which, may have a frequency of the order of 60 cycles per. second;

The. energization, of. the. relay QRL through the tube TU is controlled. by. abridge circuit. having. four arms containing resistance. The. various, resistors. are identified. by the letter K preceded by a. numeral indicating a suit-able. value-of resistance in thousands of. ohms. Thus, the reference character: 40K represents a 40,000 ohm resistor. It. will be notedv that the. grid TUG is connected to the. positive bus, L+ through. a 40,000 ohm resistor. The. cathode TUC also is connected to the positive bus L+ through a 40,000 ohm resistor. The grid TUG is 'further connected to the bus L- through the switch F C1 and four resistors in series, each having a value of 20,000 ohms. Each of these resistors is shunted by break contacts on a separate one of the down floor-call storing relays. Thus, one of the resistors is shunted by the break contacts 2DR2. A second resistor is shunted by the break contacts 3DR2', a third resistor by the contacts 4DR2 and the. remaining resistor by the contacts SDRZ. These contacts are operated respectively by the floor-call storing relays 2DR through SDR.

The cathode of the tube is additionally connected to the bus L- through three resistors connected in series.

In the specific example illustrated, these resistors may have values of 40,000, 20,000 and 20,000 ohms respectively. One of the 20,000 ohm resistors is shunted by break contacts XHTI of an up-trafiic relay XHT. Both of the 20,000 ohm resistors are shunted by make contacts ROPl of an auxiliary down-peak relay ROP.

It is desirable at this point to consider the operation of the relay QRL. The tube TU may be. designed to pass substantial current when the bias applied between the grid and cathode of the tube equals or exceeds zero. If the bias is negative, the tube does not pass current between the cathode and anode.

If no down floor calls are; registered, it follows that the break contacts; 2DR2 to 5DR2- are all closed and the grid or tube is biased negatively relative to the cathode TUC. Consequently, the relay QRL is deenergized. With the contacts in the conditions illustrated in Fig. 4, an efiective total of 60,000 ohms is present in the arm connecting the cathode TUC to the bus L-.

Should down floor calls be registered for the second and third floors the break contacts 2DR2 and 3DR2 open to introduce a total of 40,000 ohms in the associated bridge arm. This still leaves the grid TUG biased negatively relative to the cathode TUC and the relay QRL remains deenergi'zed.

Next let it be assumed that in addition to the. two calls at the second and third floors, a down floor call is registered for the fourth floor which results in opening of the break contacts 4DR2. This introduces a total of 60,000 ohms between the grid TUG and the bus L.

The grid has a zero bias relative to the cathode TUC and the tube now passes sufiicient current to energize and pick up the relay QRL.

If the break contacts XHTl open, an effective total of 80,000 ohms is in the arm connecting the cathode TUC to the bus L. This means that a total of three down floor calls no longer is sufficient to energize and pick up the relay QRL. To energize the relay a total of four down floor calls must now be registered.

If the make contacts ROPl close, the effective resistance between the cathode TUC and the bus L- is reduced to 40,000 ohms. Under these circumstances, a

'total of two-down floor calls suflice to energize the relay QRL.

In order to simplify the presentation of the invention much as possible, it has been described for a system suitable for a building having five. floors (in addition to the basement floor). As a rule, the invention will -be applied to a system having a larger number of floors. .To illustrate the performance of the; relay QRL when employed. for a building; having ten floors, in addition to the basement floor, the. switch FCl may be opened and aswitch FCZ may be closed. The grid. electrode now is connected, to the bus L- through. nine resistors, each having a value of 10,000 ohms, the resistors being connected in series. Each of the resistors is. shunted by break contacts of a separate one of the down floor-call storing relays associated with the. second to the tenth floors. With this connection and with the contacts XHTI and ROPI in the conditions illustrated in Fig. 4, a total of six down floor calls mustbe registered in order to energize and pick up the relay QRL. If the break contacts XH-T 1 are open; a total of eight down floor calls must be registered to energize and pick up the relay QRL. If the make contacts ROP1- are closed, a total of four registered down floor calls suflice to pick up the relay QRL.

Since the invention may be described adequately as appliedto the system of the Suozzo patent, it will be assumed for the remainder of this discussion that the switch PC! is closed; whereas the switch FC2 is open.

The relay QRL has make contacts QRLl which control' in partthe energization of a down-peak relay RDP. Although these contacts alone may control the energizat-ion of the relay, animprovement in the performance of the system is provided by introducing additional controls. The additional controls are responsive to the loading of the elevator cars at the lower dispatching floor while the cars are set for up travel. Thus, if the elevator car A is at the lower dispatching floor, a mechanically operated switch F-Fl is open. This switch is biased to closed position and is cam-operated to open only when the elevator car is adjacent the lower dispatching floor. If the elevator car is set for up travel the break contac-ts W11 are open. These contacts are operated by the up-preference relay W of the Suozzo patent. If the elevator car A is loaded sufiiciently to open the load switch LWL, it nowis impossible to energize the down-peak relay RDP despite the closure of the contacts QRLl. That is, asubstantial demand for elevator service in the up direction from the lower dispatching floor prevents the transfer of the system from an off-peak to a down-peak mode of operation.

Closure of make contacts RDPI of the down-peak relay RDP energizes the auxiliary down-peak relay ROP. This relay closes its make contacts ROP2 to establish with the break contacts RPT2 of a timing relay RPT a holding circuit.

The energization of the timing relay RPT is controlled by a timing circuit which includes a tube TY. This tube may be a hot-cathode tube or a cold-cathode tube and maybe of various types. For present purposes, it will be assumed that a cold-cathode thyratron is employed. The thyratron has its cathode connected to the bus L-, whereas the anode TYA is connected through the relay RPT and the make contacts ROP4 to the bus L+. A resistor RR1 is connected between the grid. or control electrode TYG and the make contacts ROP4. A capacitor RC1 is connected between the grid TYG and the cathode TYC. It will be noted that the capacitor RC1 is shunted by a resistor RR2 through break contacts ROP3 or through make contacts RDPZ.

The tube TY is of a type requiring the grid TYG to be raised to a substantial positive voltage relative to the cathode before the tube fires. The resistor RR1 has a large resistance compared to the value of resistance employed for the resistor RR2. Consequently, when the resistors are connected in series across the buses, the voltage drop across the resistor RR2 is too small to fire the tube TY. However, if the resistors are connected in series across-the buses and the contacts RDP2 and ROP3 thereafter are both open to interrupt the shunt circuit'for the capacitor RC1, the capacitor starts to charge slowly through the resistor RR1. The rate at Which voltage builds up across th Fig.

Fig. 5 shows circuits for controlling an instant dispatch relay IDB2. The energizing circuit for this relay includes, in series, break contacts S5, BS5, CS5 and D85 which are added to the auxiliary starting relays S, BS, CS and D5 of the aforesaid Suozzo patent. The energization of the relay further is controlled by four resistors RR3, BRR3, CRR3 and DRR3, one for each of the elevator cars, connected in a parallel'circuit. Each of the arms of the parallel circuit also includes a switch which is closed only when the associated elevator car is adjacent the lower dispatching floor. Thus, for the elevator car A a switch FFZ is provided which is biased to open condition but which is cam-operated to close only when the elevator car A is adjacent the first floor.

The relay IDBZ is designed to be energized sufficiently to pick up only when more than a predetermined number of elevator cars are at the lower dispatching floor. For

present purposes, it will be assumed that the relay picks up when two or more elevator cars are at the lower dispatching floor. If only one elevator car is at the lower dispatching fioor, the relay is dropped out.

Fig. 5 illustrates circuits for determining the demand for elevator service in the up direction. In the embodiment of Fig. 5, the demand for elevator service in the up direction is determined by measuring the rate at which the elevator cars when set for travel in the up direction stop at floors of the building. The measuring apparatus includes a notching or stepping switch XSS which in cludes a pair of diametrically opposite contact arms 201 and 203, which are mounted for rotation about an axis 205. Rotation of the contact arms is effected by means of a ratchet wheel 207, which is secured to the arms for rotation about the axis. A pawl 209 is positioned for reciprocation to advance the ratchet wheel 207 When the coil of the stepping switch is energized, the pawl 209 is moved downwardly without rotating the ratchet wheel as a result of the attraction of the coil for a magnetic armature secured to the pawl. At the same time, contacts XSSl associated with the stepping switch are opened. If the coil thereafter is deenergized, a spring 211 pulls the pawl 209 upwardly as viewed to advance the ratchet wheel and the contact arms one step. This operation is repeated for each energization and deenergization of the coil of the stepping switch, and such operation of stepping switches is well known in the art.

The coil of the stepping switch XSS is energized and deenergized once for each stop of each of the elevator cars. The energizing circuit for the coil is completed through any one of a plurality of parallel circuits, one for each of the elevator cars. Thus, for the elevator car A the circuit includes in series make contacts M9 of the running relay M, break contacts Mitt of the running relay M and make contacts W9 of the up-preference relay W. The make contacts M9 are designed to close slightly before the break contacts Mitt open and the make contacts M9 are designed to open slightly before the break contacts M10 close. Thus, the circuit is momentarily closed during each stop of the elevator car A while set for up travel.

The contact arms 20!. and 293, as they advance, successively engage commutator segments XCSI to XCS9. Thus, the position of the contact arms indicates the number of stops made by the elevator cars while set for up asaacs travel. If it is desired to control apparatus in accordance with a predetermined number of stops, a stop quota relay ,it is desired to control apparatus in accordance withthe time rate at whichthe stops are made. To this end, a time period relay XT is provided which is energized through make-contacts XRl of a reset relay XR. The time period relay has a substantial time delay in dropout which may be determined-at least in part, bya resistor 215 which is connected across the relay. The stepping switch must operate to' energize the stop quota relay XQ within a time interval required for the time period relay XT to drop out if the stop quota relay XQ is to be effective for a control operation.

An up trafiic relay XHT is energized only if the elevator cars have made a predetermined number of stops while set for travel in the up direction (make contacts XQI are closed) and if this number of stops has been made within the time interval measured by the time required for the time period relay XT to drop out (break contacts XR2 are closed). When the up trafiic relay XHT picks up, it completes a holding circuit through its make contacts XHT2 and through the make contacts XT1 of the time period relay. Consequently, this holding circuit is interrupted if the time period relay XT is allowed to drop out.

A resetting operation of the stepping switch XSS is initiated by energization of the reset relay XR through break contacts XT2 of the time period relay XT or through make contacts XQZ of the stop quota relay XQ. Such energization can take place only if the break contacts XSTI of the reset stop relay are closed. When energized, the reset relay XR establishes a holding circuit through its make contacts XR3 which is interrupted when the break contacts XSTI of the reset stop relay open.

The operation of the stepping switch and its associated circuits now may be considered. It will be assumed that the contact arms 201 and 293 are in their reset position, as shown in Fig. l, and that the make contacts XRi have opened to deenergize the time period relay XT. The time period relay consequently starts to time out.

During the time required for the relay XT to drop out, the contact arms 2431 and 293 are advanced one step for each car stop made by the elevator cars in service in the elevator system. It will be assumed first that two stops are made by the elevator cars before the time period relay XT drops out. Consequently, the contact arm 201 is in engagement with the commutator segment XCS3 at the time period relay XT drops out.

When the time period relay XT drops out, it opens its make contact XT1 and closes its break contacts XT2. If the up trafiic relay XHT was previously energized and was held energized through its holding circuit, the opening of the contacts XT1 deenergizes the up traffic relay.

The closing of the break contacts XT2 completes an energizing circuit for the reset relay XR through the break contacts XSTI of the reset stop relay. The reset relay XR thereupon closes its make contacts XRI to reenergize the time period relay XT. The opening of the break contacts XRZ prevents energization of the up traffic relay through the make contacts XQI of the stop quota relay. Closure of the make contacts XR3 completes a holding circuit for the reset relay XR through the break contacts XSTl of the reset stop relay. Closure of the make contacts XR4 completes an energizing circuit for the stepping switch XSS through the break contacts XSSI.

-( ionsequently, the stepping switch repeatedly steps. the

arms 201' and 203 in a clock-wise direction.

When the contact arm 201 reaches the commutator segment XCS4, an energizing circuit is established for the stop quota relay XQ. The resultant closure of the make contacts XQI has no effect on the system for the reason that the break contacts XR2 are open. Closure of the contacts XQ2 also is without effect for the reason that the contacts XR3 are closed.

In response to continued stepping of the contact arms, the contact arm finally engages the commutator segment XCS9 to complete an energizing circuit for the reset stop relay XST. This" relay opens its break contacts XSTl to deenergize the reset relay XR.

As. a result of its deenergization, the reset relay-opens its make contacts XR1 to initiate a time-measuring operation of the time period relay XT. Consequently, this relay starts to timeout. The break contacts XR2 reclose butzhave no etfect for the reason thatthemake contacts XQl are now open; The make contacts X113 open, but such' opening has no immediate efifecton the operation of the system. The make contacts XR4 open. The spring 211 now advances the contact arms to their reset positions, and the stepping switch now is conditioned to measure again the number of elevator car stops during the period being measured by the time period relay XT.

The stepping switch XSS may have a slight time delay in each stepping operation to permit pickup of the reset stop relay XST and dropout of the reset relay XR after one of the contact arms reaches'the commutator segment XCS9 before the stepping switch can operate one of the Contact arms beyond the commutator segment XCSl. Thus, the stepping switch may be given a short delay in dropout in a conventional manner.

It now will be assumed that the elevator cars make a total of three stops before the time period relay XT times out. When the contact arm 203 reaches the'commutator segment XCS4, an energizing circuit is established for the stop quota relay XQ. This relay closes its make contacts XQl to complete an energizing circuit for the up traflic relay XHT through the break contacts XR2. In addition, the make contacts XQZ close to complete an energizing circuit for the reset relay XR through the break contacts XSTi.

The up traific relay closes its make contacts )(HTZ to establish a holding circuit which is completed through the make contacts XTl of the time period relay. Consequently, if the up trafiic relay once picks up, it remains picked up until the time period relay XT is dropped out.

It. will be recalled that the energization of the stop quota relay XQ also resulted in energization and pickup of the reset relay XR. This relay closes its make contacts XR1 under the assumed conditions before the time period relay XT has dropped out. The opening of the break contacts XR2 has no immediate effect on the operation of the system. The closing of the contacts XR3 establishes a holding circuit for the reset relay XR which is completed through the break contacts XSTl of the reset stop relay XST. The make contacts XR4 close to reset the stepping switch XSS in a manner which will be clear from the foregoing discussion. It will be recalled that when the stepping switch XSS is reset, the reset relay XR is dropped out and opens its make contacts XR1 to initiate a new timing-out period for the time period relay XT.

If the number of car stops is sufiicient to again energize the stop quota relay XQ before the time period relay XT drops out, the up traffic relay XHT remains energized, the stepping switch XSS is reset, and the time-period relay is energized and started on another timing-out period. This sequence continues until the number of car stops registered is insufiicient to energize the relay XQ before the time period relay XT drops out. It will be recalled that the time period relay on dropping out opens its make contactsXT-2 to deenergize the up traflic relay XHT.

Fig. 5 illustrates circuits for controlling the reversing relay J. This relay is connected between abrush ii and the bus L through make contactsl-lCl ofthe high call relay and make contacts W10 of the up-preference relay. The contacts W10 are added to the up-preference relay of the Suozzo patent.

The brush jj is associated with a row of contact segments 2 3i and 4 which are included in the floor selector of the Suozzo patent. It will be understood that as the elevator car A,.when traveling in the up direction, approaches the second floor, the brush jj engages thecontact segment 2 As the elevator car nears the third floor, the brush jj engages the: contact segment 3 and as the car nears the fourthfloor, the brush engages the contact segment 4 The contact segments are associated with a high call circuit HCC. This circuit may be traced from the bus L+ to the contact: segment 2 as follows:

The break contacts H2 are added to the car-call-above relay H. Consequently, as long as a car call is registered for floors above the position of the elevator car A, the reversing relay' I cannot be energized through the high call circuit HCC. It will be noted that break contacts of all floor-call storing relays requiring travel of the elevator car above the second'fioor are located between the contact segment 2 and the bus L+. Consequently, if any of these contacts are opened, the reversing relay I cannot be energized.

The contact segment 3 is connected to the high call circuit HCC intermediate the contacts 3DR4 and 3UR2. Consequently, all contacts of the floor-call storing relays requiring travel of the elevator car above the. third floor are located between the contact segments 3j and. the bus- L+.

The contact segment 4f is connectedto the high call circuit HCC intermediate the contacts 4DR4 and 4UR2. Consequently, all contacts of the'fioor-call storing relays requiring travel of the elevator car above the fourth floor are located between the contact segments 4 and the bus L+.

Energization of the relay J is accompanied by closure of the make contacts J3 to establish with the make contacts W10 a holding circuit for the relay I;

OPERATION As long as the quota relay QRL is deenergized, the present elevator system works exactly in the same manner as the system shown in the Suozzo patent. Since the operation of the system of the patent is clearly set forth therein, this operation will not be here repeated. Instead, the modification in operation of the system disclosed in the patent will be primarily discussed.

In the Suozzo patent the elevator cars operate on through trips between the lower and upper dispatching floors. At each floor elevator cars are dispatched successively at intervals by suitable dispatching mechanism. Although the operation of the system disclosed in the Suozzo patent may be employed throughout the day, it is particularly suitable for oif-peak operation.

Let it be assumed that the elevator cars are not making stops while set for up travel. Under such circumstances, the relay XQ of Fig. 5 is deenergized and the break contacts XQ3 are closed.

It will be assumed further that none of the elevator cars is loaded while set for up travel at the lower dispatching fioor. Under these circumstances, the switches LWL to DLWL all are closed. V

At this stage, down floor calls are registered for the second, third and fourth floors. Such registration of calls results in opening of the break contacts 2DR2, 3DR-2 and-.4DR2 (Fig. 4-). The opening of these contacts changes the balance of the bridge associated with the tube TU sufficiently to energize the quota relay QRL and this relay closes its make contacts QRLI and QRLZ.

Energization of the high call relay HC through the contacts QRLZ results in closure of the make contacts HCI (Fig. If the elevator car A at this time is leaving the first floor in the up direction, the make contacts W are closed. Consequently, the elevator car A proceeds upwardly until the brush ij engages the contact segments 4 This occurs as the elevator car nears its stopping distance relative to the fourth floor. Since no call remains to be answered above the fourth floor, engagement of the brush ij with the contact segment 41' completes the following circuit:

L+, H2, 5DR4, 4UR2, 41', if, HCl, J, W10

The relay J closes its make contacts J3 to complete with the make contacts W10 a holding circuit. In addition, the make contacts I1 (Fig. 2) energize the relays G, E and F. These cooperate in the manner discussed in the Suozzo patent to stop the elevator car at the fourth floor. In addition, break contacts J2 open without immediate eifect on the operation of the system. As the elevator car stops at the fourth floor, the car running relay M drops out to open its make contacts M8. Since the break contacts I2 also are open, the tip-preference relay W now is deenergized. The deenergization of the relay W results in conditioning of the elevator car A for down travel in the manner discussed in the Suozzo patent.

Returning to Fig. 4, it should be noted that closure of the make contacts QRLl completes an energizing circuit for the down-peak relay RDP. This relay, in turn, energizes the auxiliary down-peak relay ROP. The auxiliary down-peak relay closes its make contacts ROP2 to establish with the break contacts RPTZ a self-holding circuit.

The energization of the relay ROP additionally results in closure of the make contacts ROPl. This modifies the balance of the bridge in such a manner that two registered down floor calls now are sufiicient to energize the relay QRL.

Inasmuch as the make contacts RDP2 are now closed, the opening of the make contacts ROP3 has no immediate etfect on the operation of the system. Closure of the make contacts ROP4connects the resistors RRl and RR2 through the contacts RDPZ across the buses. However, the discharge across the resistor RRZ is not sufficient to fire the tube TY.

The relay ROP additionally closes its make contacts ROP5 (Fig. 4). If more than one elevator car is at the lower dispatching floor at this time, the relay IDB is energized sufliciently to pick up. For example, if the elevator cars B and C are at the lower terminal floor and neither has the start signal, the switches BFFZ and CFFZ (Fig. 5 are both closed and the relay IDB consequently is energized sufficiently to pick up. The resultant closure of the contacts IDBZ (Fig. 4) completes with the make contacts ROPE a circuit around the contacts 77. By reference to the Suozzo patent it will be appreciated that the shunting of the contacts 77 eliminates the time interval normally introduced by the contacts, and one of the elevator cars is instantly dispatched.

If the elevator car B was selected as the next elevator car to leave the dispatching floor and if it was instantly dispatched as described above, the departure of the elevator car opens the switch BFFZ (Fig. 5). The relay IDB now is energized only through the resistor CRR3 and this is not sufficient to maintain the relay in its picked up position. Consequently, the make contacts IDB2 (Fig. 4) open and the elevator car C is selected and started from the lower dispatching floor after the expiration of the regular dispatching interval.

Inasmuch as the elevator car A stops at the fourth floor and is set for down travel at the fourth floor, the elevator car cancels the down floor call for the fourth floor and the break contacts 4DR2 open. The reduction ill the resistance between the grid TUG and the bus L- fies the bridge to permit pickup of the relay QRL by only two registered down floor calls.

Next let it be assumed that the elevator car A answers the down floor call at the third floor. As the elevator car stops at the third floor, the down floor-call storing relay 3DR resets in the manner set forth in the aforesaid Suozzo patent and the break contacts SDRZ (Fig. 4) consequently reclose. The closure of the contacts shunts one of the resistors of the bridge circuit associated with the tube TU leaving an effective resistance between the grid TUG and the bus L-- of only 20,000 ohms. The bridge circuit now is unable to support a discharge in the tube TU and the quota relay QRL drops out. The dropout of the quota relay results in opening of the make contacts QRL2 and the high call relay HC now drops out to open its make contacts HCl (Fig. 5) and similar contacts associated with the other elevator cars of the bank. Since the reversing relays of these elevator cars cannot now be energized, the elevator cars operate between the dispatching floors and are dispatched from such floors in the manner set forth in the aforesaid Suozzo patent.

The dropout of the quota relay QRL also results in opening of the make contacts QRLl to deenergize the down-peak relay RDP. The down-peak relay opens its make contacts RDPl without immediate effect on the operation of the system. However, the simultaneous opening of the make contacts RDPZ disconnects the resistor RR2 from the capacitor RC1. Current now is supplied to the capacitor RC1 through the resistor RRi for the purpose of increasing the charge of the capacitor.

After a time delay dependent on the time constant of the charging circuit, the capacitor RC1 has a voltage thereacross sufiiceint to initiate a discharge in the tube TY. This discharge picks up the timing relay RPT which closes its holding contacts RPTl to shunt the tube TY. In addition, the break contacts RPTZ open to deenergize the auxiliary down-peak relay ROP.

The deenergization and dropout of the auxiliary downpeak relay ROP results in opening of the make contacts ROPl to increase the effective resistance between the cathode T UC and the bus L. Such increase in effective resistance increases the number of down floor calls which must be registered before the tube TU is biased sufficiently to pick up the relay QRL.

Opening of the make contacts ROPZ has no immediate effect on the operation of the system. Closure of the break contacts ROP3 connects the resistor RR2 across the capacitor RC1 and the capacitor now starts to discharge through the resistor. Opening of the make contacts ROP4 interrupts the charging circuit for the capacitor RC1.

The relay ROP also opens its make contacts ROPS (Fig. 4) to interrupt the shunt circuit across the contacts 77. Consequently, the dispatcher shown in Fig. 4 operates in the manner discussed in the aforesaid Suozzo patent. In other words, the presence of two or more elevator cars adjacent the lower dispatching fioor no longer results in prompt dispatching of excess elevator cars.

In the next operation to be considered, it will be assumed that none of the elevator cars is loaded at the lower dispatching floor and that the elevator cars A, B andC are set for up travel. It will be assumed further that the elevator car A stops at the fourth floor in response to a car call, while the elevator cars B and C stop respectively at the third and second floors in response to car calls. The stopping of the elevator cars in response to car calls is set forth in the aforesaid Suozzo patent. 7

Since the elevator cars A, B and C are set for up travel,

the make contacts W9, BW9 and CW9 (Fig. 5) of the tip-preference relays W, BW and CW are all closed. As

v the clevatorcar A stops at the fourth floor, the. car. running relay M dropsout and thebreak contacts M10 close slightly before the make contacts M9 open. Consequently, a pulse of current is supplied to the stepping switch SS and this switch is advanced one step to bring the arm 201 into engagement with the contact segment XCSZ. In an analogous manner, as the elevator cars B and C stop at the third and second floors, two additional pulses of current are supplied to the stepping switch SS and these pulses step the arm 201 into engagement with the contact segment XCSdto-completean energizing circuit for the up stop quota relay XQ. Closure of the make contacts XQI completes with the break contacts XR2; an energizing circuit for the up trafiic relay The relay XQalso closes its makc'contacts- XQ2 to complete with the contacts XSTl an energizing circuit for the reset relay XR. Inasmuch as the operation of the reset relay XR and the time period relay XT have been discussed fully above, further discussion at this time of the operation of these relays is not required.

The pickup of the relay XHT is accompanied by opening of the break contacts XHTl and this increases the effective resistance between the cathode TUC and the bus L to 80,000 ohms. At this instant, it will be assumed thatdown floor calls are registered at the second, third andfourth floors by a sequence which will be understood from. the Suozzo patent. As a result of the registration of the down floor calls, the break contacts 2DR3, 3DR3 andv 4DR3, open to introduce a total of 60,000 ohms effective resistance between the grid, TUG and the bus I However, because of the opening of the break contacts XHTl, the registration of three down fioorcalls is not sufii'cient to produce a discharge in the tube TU.

As the elevator car A leaves the fourth floor in the up direction it will be assumed that a down, floor call is registered also at the fifth floor. The resultant opening o fithe break contacts 5DR3' raises the effective resistance between the grid TUG and the bus: LV- to 80,000 ohms and this is suflicient to discharge the tube TU for the purpose of picking up the relay QRL. The effect of pickup of the relay Q'RL on the operation of. the system has been discussed above;

As previously pointed out, the presence of. a substantially loaded elevator car set for up travel at the lower dispatching floor prevents pickup of the down-peakrelay RDP. For example, if the elevator car A is atthe lower dispatching floor the switch FFl is open. If the car is set for up travel, the contacts W11 areopen. If the elevator car is substantially loaded, the switch LWL is open. The opening of these switches, and contacts prevents energization of the down-peak relay RDP. Under such circumstances, if the quota, relay QRL picks .up, it energizes the high call relay HC' to permit high call reversal operation of the elevator cars. However, since the down-peak relay R'D'P' and the auxiliary down-peak relay ROP are not energized, under these conditions, the presence of an excess number of elevator cars at the lower dispatching floor does not result in prompt dispatching, of the excess elevator cars.

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

' invention are possible.

We claim as our invention:

1. In an elevator system, a structure having a. plurality of floors includingv a pair of terminal floors and intermediate floors between the terminal floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, motive means tor moving the elevator cars, and control means cooperating with the motive means to control movement in twodirections and stopping of the elevator 'cars, said control means having a first condition establishing a first mode of operation of the elevator cars wherein the elevator cars travel in, throughrtrips between the.

terminal floors and. a second condition establishing-a second mode of. operation of the elevator carswwherein at least part of the cars may reverse at one of the intermediate fioors, transfer means having a. first response to a firsttraflic condition representative of a demand for elevator service in a first direction. for transferring the control means from the, first to the second condition, and means responsive to asecond trafiic condition representative of a demand for elevator service in a second direction for establishing a second response of the transfer means to the first traffic condition for transferring-the control means from the first to the second condition.

2. In an elevator system, a structure having a plurality of floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floor-s, motive means for moving the elevator cars, callmeans operable for registering calls for. elevator service in a first direction from said floors, and control means cooperating with the motive means and the call means to control movement of the elevator cars, and stopping of. the elevator cars at floors for which calls are registered by the call means, said control means having a first condition establishing a first mode of operation providing substantially balanced service for the floors in two directions of travel of the elevator cars, said control means having a second condition establishing a second mode of operation expediting elevator service in said first direction, transfer means having a first response to a function of calls. registered by the. call means for transferring the control means from the first to the second condition, and means responsive to a traffic condition for establishing a second response by said transfer means to calls registered by the call means for transferring the control means from the first to the second condition.

3. In an elevator system, a structure having a plurality of floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, motive means for moving the elevator cars, call means operable for registering calls for elevator service in a first direction from said floors, and control means cooperating with the motive means and the call means to control movement of the elevator cars and stopping of the elevator cars at floors for which calls are registered by the call means, said control means having a first condition establishing a first mode of operation providing substantially balanced service for the floors in two directions of travel of the elevator cars, said control means having a second condition establishing a second mode of operation expediting elevator service in said first direction, transfer means having a first response to a function of calls registered by the call means for transferring the control means from the first to the second condition, and means responsive to traffic conditions of the elevator cars while set for travel in a second direction for establishing a second response by said transfer means to calls registered by the call means for transferring the control means from the first to the second condition.

4. In an elevator system, a structure having a plurality of floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, motive means for moving the elevator cars, call means operable for registering calls for elevator service in a first direction from said floors, and control means cooperating with the motive means and the call means to control movement of the elevator cars and stopping of the elevator cars at fioors for which calls are registered by the call means, said control means having a first condition establishing a first mode of operation providing substantially balanced service for the floors in two directions of travel of the elevator cars, said control means having a second condition establishing a second mode of operation expediting elevator service in said first direction, transfer means having a first response to a function of calls registered by the call means for trans aeazo'sa ferring the control means from th e first to the second condition, and means responsive to the rate at which elevator cars set for travel in the up direction stop for establishing a second response by said transfer means to calls registered by the call means for transferring the control means from the first to the second condition.

5. In an elevator system, a structure having a plurality of floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, motive means for moving the elevator cars, call means operable for registering calls for elevator service in a first direction from said floors, and control means cooperating with the motive means and the call means to control movement of the elevator cars and stopping of the elevator cars at floors for which calls are registered by the call means, said control means having a first condition establishing a first mode of operation providing substantially balanced service for the floors in tWo directions of travel of the elevator cars, said control means having a second condition es tablishing a second mode of operation expediting elevator service in said first direction, transfer means having a first response to a function of calls registered by the call means for transferring the control means from the first to the second condition, and means responsive to the rate at which elevator cars set for travel in the up direction stop for establishing a second response by said transfer means to calls registered by the call means for transferring the control means from the first to the second condition, and means responsive to a predetermined loading of at least part of the elevator cars while .et for travel in the up direction for modifying the response of the transfer means to calls registered by the call means.

6. In an elevator system, a structure having a plurality of floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, motive means for moving the elevator cars, and control means cooperating with the motive means to control movement and stopping of the elevator cars, said control means having a first condition establishing a first mode of operation of the elevator cars and a second condition establishing a second mode of operation of the elevator cars, transfer means having a first response to a first traffic condition for transferring the control means from the first to the second condition, and means responsive to a second tra'liic condition for establishing a second response of the transfer means to the first trafiic condition for transferring the control means from the first to the second condition, and means responsive to a predetermined loading of at least part of the elevator cars while set for travel in the up direction for preventing a transferring operation of the transfer means. 7

7. In an elevator system, a structure having a plurality of floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, motive means for moving the elevator cars, means establishing a predetermined minimum interval between dispatch of succesive elevator cars from one of said floors, and control means cooperating with the motive means to control movement and stopping of the elevator cars, said control means having a first condition establishing a first mode of operation of the elevator number of the elevator cars, said number being atleast one and being less than the total number of elevator cars,

8. In an elevator system, a structure having a plurality of floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, motive means for moving the elevator cars, means establishing a predetermined minimum interval between dispatch of successive elevator cars from one of said floors, and control means cooperating with the motive means to control movement and stopping of the elevator cars, said control means having a first condition establishing a first mode of operation of the elevator cars and a second condition establishing a second mode of operation of the elevator cars, transfer means having a first response to a first traffic condition for transferring the control means from the first to the second condition, and means responsive to a second trafiic condition for establishing a second response of the transfer means to the first traflic condition for transferring the control means from the first to the second condition, said transfer means being effective when operating in response to said first trafiic condition for dispatching in a time less than said interval any elevator car present at the last-named floor in excess of a predetermined number of the elevator cars, said number being at least one and being less than the total number of elevator cars.

9. In an elevator system, a structure having a plurality of floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, motive means for moving the elevator cars, means establishing a predetermined minimum interval between dispatch of successive elevator cars from one of said floors, call means operable for registering calls for elevator service in a first direction from said floors, and control means cooperating with the motive means and the call means to control movement of the elevator cars and stopping of the elevator cars at floors for which calls are registered by the call means, said control means having a first condition establishing a first mode of operation providing substantially balanced service for the floors in two directions'of travel of the elevator cars, said control means having a second condition establishing a second mode of operation expediting elevator service in said first direction, transfer means having a first response to a function of calls registered by the call means for transferring the control means from the first to the second condition, and means responsive to a traflic condition for v establishing a second response by said transfer means to calls registered by the call means for transferring the control means from the first to the second condition, said transfer means being effective when operating in response 7 to said first trafiic condition for dispatching in a time less than said interval any elevator car present at the lastnamed floor in excess of a predetermined number of the elevator cars, said number being at least one and being less than the total number of elevator cars.

10. In an elevator system, a structure having a plurality of floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, motive means for moving the elevator cars, means establishing a predetermined minimum interval between dispatch of successive elevator cars from one of said floors, call means operable for registering calls for elevator service in a down direction from said floors, and control means cooperating with the motive means and the call means to control movement of thetelevator cars and stopping of the elevator cars at floors for which calls are registered by the call means, 7 said control means havinga first condition establishing elevator service in said down direction, transfer means having a first response to a function of calls registered by the call means for transferring the control means from the first to the second condition, and means responsive to the rate at which elevator cars set for travel in the up direction stop for establishing a second response by said transfer means to calls registered by the call means for transferring the control means from the first to the second condition, said transfer means being effective when operating in response to said first traffic condition for dispatching in a time less than said interval any elevator car present at the last-named floor in excess of a predetermined number of the elevator cars, said number being at least one and being less than the total number of elevator cars.

11. In an elevator system, a structure having a plurality of floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, motive means for moving the elevator cars, and control means cooperating with the motive means to control movement and stopping of the elevator cars, said control means having a first condition establishing a first mode of operation of the elevator cars and a second condition establishing a second mode of operation of the elevator cars, transfer means having a first response to a first trafiic condition for transferring the control means from the first to the second condition, and means responsive to a second traffic condition for establishing a second response of the transfer means to the first trafiic condition for transferring the control means from the first to the second condition, and means responsive to an operation of the transfer means for modifying the first traffic condition necessary to maintain the transfer means operated.

12. In an elevator system, a structure having a plurality of floors, a'plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, motive means for moving the elevator cars, call means operable for registering calls for elevator service in a first direction from said floors,

and control means cooperating with the motive means and the call means to control movement of the elevator cars and stopping of the elevator cars at floors for which calls are registered by the call means, said control means having a first condition establishing a first mode of operation providing substantially balanced service for the floors in two directions of travel of the elevator cars, said control means having a second condition establishing a second mode of operation expediting elevator service in said first direction, transfer means having a first response to a function of calls registered by the call means for transferring the control means from the first to the second condition, and means responsive to a traffic condition for establishing a second response by said transfer means to calls registered by the call means for transferring the control means from the first to the second condition, and means responsive to an operation of the transfer means for decreasing the function of registered calls required to maintain the transfer means operated.

13. In an elevator system, a structure having a plurality of floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve the floors, motive means for moving the elevator cars, and control means cooperating with the motive means to control movement and stopping of the elevator cars, said control means having a first condition establishing a first mode of operation of the elevator cars and a second condition establishing a second mode of operation of the elevator cars, transfer means having a first response to a first trafiic condition for transferring the control means from the first to the second condition, and means responsive to an operation of the transfer means for modifying the first traffic condition necessary to maintain the transfer means operated.

No references cited.

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