US2772752A - Elevator systems - Google Patents

Description

Decq 4, 1956 J. suozzo 2,772,752

ELEVATOR SYSTEMS Filed Jan. 25, 1954 9 Sheets-Sheet 2 .eue awz 831B BX m 1 0 II 0 v BXlo L-3 1+3 L-B WITNESSES: INVENTOR Fig.2. John Suozzo.

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ELEVATOR SYSTEMS Filed Jan. 25, 1954 9 Sheets-Sheet 9 (I n: x x E a: .9 Q a o o D 3 3 3 o x LO cu m m 3 .0 m E En $0 In 101: .n N x g 5,? a:

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5, Q7 uzz/MW ATTORN EY United States Patent ELEVATOR SYSTEMS.

John Suozzo, Paramus, N. 1., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application January 25, 1954, Serial No. 405,744

40 Claims. (Cl. 187--29) This invention relates to elevator systems employing call registration mechanism and it has particular relation to elevator systems wherein banks of elevator cars are arranged to respond to registered calls for elevator service in an orderly sequence.

In an elevator system it is desirable that the elevator cars provide reasonably uniform elevator service for all of the floors served by the elevator cars. Furthermore, in order to increase the efiiciency of elevator service it is desirable that unnecessary stops of elevator cars be avoided. To illustrate conditions which may arise, consideration may be given to the case wherein an elevator car has stopped at a floor in response to a registered down floor or corridor call. If the elevator car is fully loaded at the floor, the call may be registered immediately after the elevator car leaves and the elevator car may be forced to bypass registered calls for service in the down direction from lower floors of; the building,

Under such circumstances, the elevator car may be forced to return to serve the reregistered call before it can serve other calls for service which may have been registered prior to the registration of the reregistered call.

Furthermore, if an elevator car stops in response to.

a reregistered call for elevator service at a floor, the interval between the successive stoppings of an. elevator car at such floor may be so small that few passengers board the elevator car which stops in response to the reregistered call. When the. demand for elevator service is heavy it is desirable that a substantial load be taken by each car at each stop of the car.

As a further example of a situation which may result in inefficient elevator operation, consideration may be given to an elevator system. wherein a number of elevator cars normally operate between two terminal floors, but wherein an elevator car may be required, under certain conditions, to proceed beyond one of the terminal floors to serve an extension floor such as a basement floor. If more than one of the elevator cars is. assigned to answer a call for service from such basement floor, an unnecessary stop and ineificient service may result.

In accordance with the invention, calls for elevator service are arranged in groups. Although the grouping may be for up calls or for both up and down calls, it will be assumed that the grouping is of down calls only. Although a larger number of groups may be employed, in a preferred embodiment of the invention the calls are arranged-in first and second groups.

The assignment of a floor or corridor down call to one of the groups is determined by the registration and reregistration of calls. For example, a down call registered from a floor may be assigned to the first group. If the call is reregistered immediately after an elevator car stops at the floor, the reregistered call may be assigned floor in response to the reregistered call, the v latest registration may be assigned to the first group. In this way,

2,772,752 Patented Dec. 4, 1956 successive calls from a floor may be assigned alternately to the two groups.

An elevator car may be selectively assigned to answer calls in the groups in an orderly sequence. In a preferred embodiment of the invention, the car may be assigned to answer calls. in the two groups alternately. Thus, the elevator car may answer all of the down calls in the first group and then proceed to answer all of the calls in the second group. After answering all of the. calls in the second group, the elevator car then may be reassigned to answer the calls in the first group. This alternating assignment may proceed as long as conditions warrant.

Each elevator car in the system. may be conditioned to reverse at the highest call for elevator service which is registered. In a preferred embodiment of the invention, the car is conditioned to reverse if traveling in the up direction at the highest floor for which a down call is registered in the group to which the car is assigned.

'ice

If a car call is registered for a higher floor, the car maybe conditioned to answer the car call before it reverses.

Each elevator car in an elevator system which stops in response to a registered down call from one of the floors cancels such, call. If the elevator car, while traveling down, stops at such floor in response to a registered car call, it also cancels any registered down floor call.

As previously pointed. out, the elevator cars in an elevator system may be arranged to operate normally between terminal floors. In accordance with the invention if a call for service is received from an extension floor such as a basement floor, all of the elevator cars may be assigned to answer such call. The first of the elevator cars to accept the assignment cancels the assignment for the remainder of the elevator cars. In addition, if one of the elevator cars is assigned to proceed to the basement floor at the time the call for elevator service is registered at the basement floor, no other elevator car receives the assignment to. proceed to the basement floor.

It is, therefore, an object of the invention to provide an improved elevator system wherein calls for elevator service in a predetermined direction are arranged in predetermined groups.

It is a further object of the invention to provide an elevator system wherein successive calls for elevator service from a floor are assigned alternately to predetermined groups.

It is also an object of the invention to provide an elevator system employing two call registering devices for registering calls for elevator service for a floor whereinonly one of the call registering devices is effective at any one time, and wherein the stopping of the elevator car at the floor transfers the effective condition from one to the other of the call registering devices.

It is an additional object of the invention to provide an elevator system wherein calls for elevator service in a predetermined direction are assigned to groups, and: wherein an elevator car is assigned to answer calls for elevator service in one of said groups before pro.- ceeding to answer calls for elevator service in another of said groups.

It is another object of the invention to provide an elevator system wherein an elevator car must answer predetermined other calls for elevator service before it can stop more than a predetermined number of times at the one floor, in response to calls for elevator service from such floor.

It is a still further object of the invention to provide an elevator system wherein calls for elevator service from the floors are divided into groups, and wherein the stopping of an elevator car at a floor in response to a registered car call set for travel in a predetermined direction cancels any registered floor call for such floor regardless of the group to which the floor call is assigned.

Still another object of the invention is to provide an elevator system wherein a plurality of elevator cars normally operate between terminal floors, and wherein only one of the elevator cars may be required to proceed beyond one of the terminal floors in response to a call for elevator service for an extension floor located beyond the last-named terminal floor.

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

Figure 1 is a view in elevation with parts broken away of an elevator system embodying the invention;

Fig. 2 is a schematic view showing control circuits suitable for the system of Fig. 1;

Fig. 2A is a schematic view showing electromagnetic switches and relays employed in the circuits of Fig. 2. If Figs. 2 and 2A are placed in horizontal alignment, it will be found that the respective contacts and coils of the two figures are substantially in horizontal alignment.

Fig. 3 is a schematic view in straight line form showing floor call circuits suitable for the system of Fig. 1;

Fig. 3A is a schematic view showing electromagnetic switches and relays employed in the circuits of Fig. 3. If Figs. 3 and 3A are placed in horizontal alignment, it will be found that corresponding contacts and coils of the two figures are substantially in horizontal alignment.

Figs. 4 and 5 are schematic views in straight line form showing additional circuits suitable for the system of Fig. 1; and

Figs. 4A and 5A are schematic views of electromagnetic switches and relays employed in the circuits respectively of Figs. 4 and 5. If Figs. 4 and 5 are placed in horizontal alignment respectively with Figs. 4A and 5A, it will be found that corresponding coils and contacts of the related figures are substantially in horizontal alignment.

The invention is suitable for banks of elevator cars including various numbers of cars serving buildings having various numbers of fioors. However, the invention may be discussed adequately for a bank of elevator cars having two cars A and B, serving a building having six floors including a basement floor.

Inasmuch as the elevator cars of the bank have similar control circuits, it will suffice to discuss the control circuits for the elevator car A. Similar components for the remaining elevator car are identified by the same reference characters preceded by the letter corresponding to the appropriate elevator car. For example, the reference character E designates the slowdown inductor relay for the elevator car A, whereas the reference character BE designates the slowdown inductor relay for the car B.

Electromagnetic relays and switches employed in the elevator system may have break contacts which are closed when the relays and switches are deenergized and dropped out. Also, the relays and switches may have make contacts which are closed when the switches and relays are energized and picked up. Break contacts are open when the switches and relays are energized and picked up, whereas make contacts are open when the switches and relays are deenergized and dropped out.

In order to distinguish the sets of contacts employed for each relay, each set will be designated by the reference character for the relay followed by the numeral corresponding to the specific set of contacts. For example, the reference character U3 designates the third set of contacts for the up switch U.

In order to facilitate the consideration of the invention, the following apparatus is listed:

APPARATUS FOR CAR A VHigh-speed relay UUp switch 4 I DDown switch GInductor holding relay ESlowdown inductor relay F--Stopping inductor relay MCar running relay DR--Door safety relay W-Up-direction preference relay Down-direction preference relay HHigh car-call relay T-Car-call stopping relay SFloor-call stopping relay K-First high floor-call relay KX-Second high floor-call relay JReversing relay PBy-pass relay APPARATUS COMMON TO ALL CARS bUR and EUR to 4URUp call-storing relays ZDR to 5DR First down call-storing relays ZDX to 5DX'Second down call-storing relays 25 to 5SDown call-control relays FW First wave relay SW--Second Wave relay Q-Transfer control relay Fig. 1 shows the mechanical arrangement of various parts of the elevator system. In Fig. 1, a cable 10 passes over a sheave 11 and has its ends attached respectively to the elevator car A and to a counterweight 12. The sheave 11 is secured to the shaft 13 or a driving motor 14. A conventional spring-applied electromagneticallyreleased elevator brake 15 is associated with the shaft of the motor 14.

In the operation of the elevator cars, certain contacts are made or broken as each elevator car reaches predetermined positions in its hoistway. Although each elevator car may actuate suitable switches located in the hoistway, it is common practice to provide a floor selector for this purpose. A typical floor selector 16 is illustrated for the car A.

The floor selector 16 has a brush carriage 17 on which suitable brushes are mounted for movement relative to contact segments in accordance with motion of the elevator car. In Fig. 1, two brushes 31 and 34 are illustrated which coact respectively with rows of contact segments al, etc., and db, etc.

The brush carriage 17 may be reciprocated in accordance with movement of the elevator car, but at a much slower rate, by means of a screw 18 which is coupled to the shaft 13 through suitable gearing.

As the elevator car proceeds from the basement floor to the fourth floor the brush 34 successively engages the contact segments db and all to d4 as the elevator car occupies positions successively adjacent the basement and first to fourth floors for the purpose of controlling certain circuits to be discussed below. Although only two rows of contact segments are illustrated in Fig. 1, additional similar rows may be employed in the manner discussed below. In addition the carriage 17 carries a cam 49 for successively opening normally-closed mechanical switches 52 to 55 as the elevator car proceeds upwardly for purposes to be discussed below. The cam has a length capable of bridging two of the switches.

The elevator cars may be of the automatic type which are controlled entirely by passengers desiring elevator car service. However, for present purposes, it will be assumed that elevator cars are of the attendant-operated type. Thus, the elevator car A has a switch CS which is operated by the car attendant to engage a contact CS1 when the elevator car is to start. The elevator car also has a number of car-call push buttons be and 1c to 5c. The numeral (or letter b) for each car-call push-button reference character designates the floor with which the push button is associated. Thus, if a passenger desires to be discharged at the fifth floor, the car attendant would press the push button 50.

A slowdown inductor relay E and a stopping inductor relay-F are employed in conditioning the elevator car A to stop at a floor. When the elevator car is to stop at a floor, the coil for the slowdown inductor relay E is energized. Such energization does not result in pickup of the break contacts E1 and E2 until the elevator car reaches predetermined positions wherein the inductor relay is adjacent a magnetic inductor plate UEP or DEP. One of the inductor plates UEP is provided for each of the floors at which the elevator car A is to stop during up travel. When the elevator car is a predetermined distance from a floor at which it is to stop, the upinductor plate UEP for the floor is adjacent the inductor relay E and completes a magnetic circuit for opening the break contacts E1. Such opening initiates a slowdown of the elevator car.

In a similar manner, a down-inductor plate DEP is provided for each floor at which the elevator car approaches a floor at which it is to stop, the inductor plate DEP completes a magnetic circuit for the inductor relay E to open the break contacts E2 and initiate a slowdown of the elevator car A.

In a somewhat similar manner the stopping-inductor relay F cooperates with up inductor plates UFP and down-inductor plates DFP to bring the elevator car to a stop at any desired floor. Thus, when the elevator car approaches a floor at which it is to stop when traveling in the up direction, one of the inductor plates UFP completes a magnetic circuit for the inductor relay to open the break contacts F1. If the elevator car is traveling in a down direction, one of the inductor plates DFP cooperates with the inductor relay to open the break contacts F2 a short distance in advance of the floor at which the elevator car is to stop. Such inductor relays are well known in the art. When one of the sets of contacts of the inductor relays opens it may remain open until the associated relay is deenergized, even though such relay is displaced from its inductor plates.

Calls for elevator car service from pasengers located at various floors served by the elevator cars are registered by suitable push buttons located at the various floors. For example, at the fourth floor, an up push button 4U may be operated to register a call for up elevator car service. A similar push button would be located at each floor from which up elevator car service is desired. Each up push button is identified by the reference character U preceded by a numeral corresponding to the floor at which the push button is located. Each up push button is common to all of the elevator cars. (identified by the letter D preceded by a numeral corresponding to the floor at which the push button is located) is located at each hall or floor from which down elevator car service is desired. The down-call push button 4D is illustrated in Fig. l for the fourth floor.

A suitable signal such as a lamp 61 is provided in each of the elevator cars to signal, when operated, that an elevator car should proceed to the basement floor.

A switch, such as the switch PE, is located in each of the elevator cars and is operated when the elevator car is to run express.

Figure 2 Fig. 2 shows various control circuits for the elevator system. Although various motor drives may be employed for the system, it will be assumed that a drive of the variable-voltage type is employed. In such a drive, the motor 14 is a direct-current motor which has its armature 14A energized from the armature GA of a directcurrent generator GE. The direct-current generator is rotated at a constant rate by a suitable motor (not shown). The armatures 14A and GA, together with a generator series field winding GS, are connected by a circuit 22 in series in a loop circuit. The field winding 14F for the motor 14 is connected directly to a source In an analogous manner, a down push button 6 of direct current represented by the buses, L+3 and L3.

The release coil for the brake 15 is connected for energization across the buses L+3 and L-3 either through make contacts U1 of an up switch or make contacts D1 of a down switch.

The direction of travel of the elevator car A is determined oy the polarization of the generator field winding GP. When the make contacts D2 and D3 of the down switch are closed, the generator field winding is connected through a resistor R1 across the buses L+3 and L.-3 for energization with proper polarity for down travel of the elevator car. If the generator field winding is connected through the resistor R1 and the make contacts U2 and US of the up switch across the buses L+3 and L-3, the polarity of energization of the field winding is suitable for up travel of the elevator car. Maximum speed of the elevator car is obtained by shunting the resistor R1 through make contacts V1 of a speed relay.

For up travel the speed relay V is energized through break contacts E1 of the slowdown inductor relay, normally-closed contacts of an upper cam-operated limit switch VTU and make contacts U4 of the up switch. if the elevator car is to slow down adjacenta floor at which it is to stop, the break contacts E1 of the slowdown inductor relay open to deenergize the speed relay V. Also, if the car reaches its upper limit of travel, a cam opens the limit switch VTU to deenergize the speed relay.

For down travel, the speed relay V, is energized through break contacts E2 of the slowdown inductor relay, normally-closed contacts of a cam-operated lower limit switch VTD and make contacts D4 of the down switch. If the elevator car is to slow down as it approaches a floor at which it is to stop, the break contacts E2 open to deenergize the speed relay. If the car nears its lower limit of travel, a cam opens the lower limit switch VTD to deenergze the speed relay.

By manipulation of his car switch CS, a car attendant controls the initial energization of a car running relay M and either the up switch U or the down switch D. The relays and switches can be energized only if make contacts DRI of a door safety relay are closed. The relay DR is energized only when certain safety devices 23 are closed. These safety devices may include contacts which are closed only if the various hoistway doors and the car doors are closed.

It will be assumed that the elevator car stops automatically in response to registered car calls and registered floor or hall calls. if the elevator car is conditioned for up travel, make contacts W1 of the up-direction preference relay are closed, and the following circuit is established by operation of the car switch:

L+3, CS, CS1, W1, F1, STU, U, M, DRI, L3- This conditions the elevator car for up travel. It will be noted that energization of the up switch U results in closure of the make contacts US to establish a holding circuit around the car switch and the contacts W1. Consequently, stopping of the elevator car is independent, of the condition of the car switch.

When the elevator car A approaches a floor at which it is to stop, the stopping inductor relay finally opens its break contacts F1 to deenergize the up switch U and the car running relay M. As the elevator car nears its upper limit of travel, a cam opens the normally-closed limit switch STU to deenergize the up switch U and the car running relay M.

It the elevator car is conditioned for down travel, the make contacts X1 of the down-direction preference relay are closed. An operation of the car switch completes the following circuit:

L+3, CS, CS1. X1, F2, STD, D, M, DRl, L-3

Operation of the down switch D closes make contacts D5 to complete a holding circuit around. the car switch and the contacts X1.

If the down-traveling elevator car approaches a floor at which it is to stop, the stopping inductor relay finally opens its break contacts F2 to deenergize the down switch D and the car running relay M. As the elevator car nears its lower limit of travel, the normally-closed limit switch STD is opened by a cam to assure deenergization of the down switch D and the car running relay.

The coils of the inductor relays E and F, and the coil of an inductor holding relay G are energized through make contacts M1 of the car running relay, and any one of three sets of make contacts. Thus, if the elevator car is to stop in response to a car call, the make contacts T1 close to energize the coils. If the elevator car is to reverse at an intermediate floor, the make contacts J1 of a reversing relay close to energize the coils. If the ele vator car is to stop in response to a registered floor or hall call, the make contacts Sll of the floor call stopping relay close to energize the coils. When the inductor holding relay G is once energized, it closes its make contacts G1 to establish a holding circuit until the contacts M1 of the car running relay open. The energization of the stopping inductor relay F also is controlled by break contacts V2 of the speed relay.

The up-direction preference relay W can be energized only if the elevator car is not traveling down (break contacts D6 are closed), the elevator car is not conditioned for down travel (break contacts X2 are closed), the reversing relay is not energized (break contacts 12 are closed), and the elevator car is not adjacent its upper limit of travel (normally-closed cam-operated switch 3OT is closed).

The up-direction preference relay W, when once energized, is deenergized in either of two ways. As the elevator car reaches its upper limit of travel, a cam opens the normally-closed limit switch 3OT to deenergize the up-direction preference relay. In addition, if the elevator car is to reverse at an intermediate floor, the break contacts J2 of the reversing relay open. Consequently, as the elevator car comes to stop at the intermediate fioor, the make contacts M2 of the car running relay open to complete the deenergization of the up-direction preference relay.

The down-direction preference relay X can be energized only if the elevator car is not traveling up (break contacts U6 are closed), the up-direction preference relay W is not energized (break contacts W2 are closed), and the elevator car is not adjacent its normal lower limit of travel at the first floor (limit switch 303 is closed).

When once energized, the down-direction preference relay normally can be deenergized only as it nears its normal lower limit of travel, Under such circumstances, a cam opens the normally-closed limit switch 30B to deenergize the down-direction preference relay.

When the elevator car is to proceed to the basement floor the car button in: is operated to connect through its contacts bc2 the basement signal relay Xla across the resistor R2 for energization and pick up. Consequently, when the switch 30B opens, the relays X and Xla remain energized through the contacts of the car button. Under these circumstances the relays are not deenergized until the car nears the basement floor to open its normally-closed limit switch 31B.

Figure 3 In Fig. 3 circuits are illustrated for registering floor or corridor calls and for cancelling such calls as they are answered.

The upper portion of Fig. 3 illustrates circuits for registering and cancelling floor or corridor calls for elevator service in the down direction. Such calls are registered by operation of the push buttons 2D to which are located respectively at the second to fifth floors.

The push buttons control the operation of two groups of down call-storing relays. The first group contains the first down call-storing relays 2DR to SDR respectively for the second to fifth floors. The second group of relays includes the second down call-storing relays ZDX to 5DX respectively for the second to fifth floors. Each of these call-storing relays has associated therewith a can celling coil which is identified by the same reference character employed for the relay followed by the sufiix N. Each of the cancelling coils is wound on the same core with the coil of its associated relay. When energized, the cancelling coil develops a magnetomotive force acting in opposition to that of the coil of the associated relay and consequently, resets the relay. Such cancelling coil construction is well known in the art.

The cancelling coils ZDRN to SDRN are energized respectively through the contact segments b2 to [15 which are mounted on the selector 16 of Fig. 1. A brush 32 mounted on the carriage 17 of Fig. 1 engages the contact segments [25 to b2 successively as the elevator car moves in the down direction.

In a similar manner the cancelling coils ZDXN to SDXN are energized respectively through contact segments c2 to c5, which are mounted on the floor selector 16 of Fig. 1. It will be understood that as the elevator car moves down from the fifth floor, the brush 33 which is mounted on the carriage 17 of Fig. l successively engages the contact segments 05 to 02.

Each of the contact segments for the elevator car A in Fig. 3 is connected to a similar contact segment associated with the elevator car B, and the contact segments for the elevator car B are similarly engaged by brushes mounted on the floor-selector carriage for the elevator car B.

Inasmuch as the circuits for registering down floor calls are similar for each of the floors, it is believed that the construction of these circuits will be understood more clearly by a discussion of the circuits for one of the floors such as the fourth floor. With the circuits in the conditions illustrated in Fig. 3, let it be assumed that a floor call is registered by operation of the push button 413. In response to such operation, the following circuit is established:

L+3, 4D, 451, mm, 4BR, L3

As a result of its energization the relay 4DR closes its make contacts 4DR1 to establish a holding circuit around the push button 4D and the break contacts 481. In addition, the break contacts 4DRZ open to prevent energization of the second down call storing relay 4DX. Closure of the make contacts 4DR3 completes with the break contacts 4DX3 and the make contacts Q2 of a transfer control relay an energizing circuit for the down call control relay for the fourth floor. It will be assumed for the present that the transfer control relay Q is permanently picked up.

Down call control relays 28 to 58 are provided respectively for the second to fifth floors. In accordance with the convention here adopted, the numeral prefix in each case designates a floor with which the relay is associated.

As a result of its energization the down call control relay 45 opens its break contacts 451 to prevent subsequent energization therethrough of the first down call storing relay i-DR. In addition, make contacts 482 close to prepare for subsequent energization of the second down call storing relay 4DX. Closure of make contacts 483 completes a holding circuit around the make contacts 4DR3.

At this stage, a call in the down direction is registered by the first down call-storing relay 4DR, and this call is retained until it is cancelled as the elevator stops while set for the down direction at the fourth floor.

it will be assumed that the elevator car A now approaches the fourth floor while set for travel in the down direction and stops at the fourth floor. As the elevator car stops, the brush 32 engages the contact segment M to complete the following cancelling circuit:

L+3, 4DR1, 4DX1, 4DRN, b4, 32, M3, X3, P1, L3

As a result of its energization the cancelling coil 4DRN neutralizes the coil of the relay 4DR and the relay drops out or resets. In dropping out the relay 4DR opens its make contacts 4DR1 and closes its break contacts 4DR2 to prepare the second down call storing relay 4DX for subsequent energization. in addition, the make contacts 4DR3 open but the relay 45 remains energized through the make contacts 453.

Let it be assumed next that as the elevator car A proceeds down from the fourth floor, a down call is reregistered by another operation of the button 4D. Such operation now completes the following circuit:

The second down call-storing relay 4DX now is energized and closes its make contacts 4DX2 to establish a holding circuit around the push button 4D and the contacts 482. In addition, break contacts 4DX1 open to prevent energization therethrough of the first down call-storing relay 4BR. Opening of the break contacts 4DX3 deenergizes the down call-control relay 4S and this relay drops out to close the break contacts 481 which partially prepares the first down callstoring relay 4DR for subsequent energization. Make contacts 432 open, but such opening does not affect the energization of the relay 4DX. The holding contacts 483 also open.

The down floor call registered by the second down callstoring relay 4DX remains registered until an elevator car set for down travel stops at the fourth floor. It will be assume that the elevator car B now stops at the fourth floor. In stopping the elevator car B completes the following cancelling circuit:

The energized coil 4DXN resets the second down c-allstoring relay 4DX.

In dropping out, the second down call-storing relay 4DX closes its break contacts 4DX1 and 4DX3 and opens its make contacts 4DX2 to restore the circuits to the conditions illustrated in Fig. 3. Continued operations of the push button 4D consequently can cause a repetition of the above-discussed cycle. In this way, successive down floor calls may be assigned alternately to each of two call storing relays for each of the second to fifth floors.

The lower portion of Fig. 3 illustrates circuits for registering floor or corridor calls for elevator service in the up direction. Such calls are registered as a result of energization of the up call-storing relays bUR and lUR to 4UR respectively for the basement and first to fourth floors. These relays are energized respectively by operation of push buttons [2H and 1U to 4U. Each of the relays is provided with a cancelling coil identified by the same reference character followed by the sufiix N. The cancelling coils are energized respectively through contact segments db and all to d4 which are mounted on the floor selector 16 of Fig. 1. As the elevator car A proceeds in the up direction from the basement floor, the brush 34 which is mounted on the carriage 17 of Fig. 1 successively engages the contact segment db and d1 to d4. Each of the contact segments is connected to a corresponding contact segment for the elevator car B.

Since all of the up call-storing relays operate in a similar manner, the construction of the circuits associated therewith will be understood by a typical operation described for the fourth floor. Let it be assumed that a call for up service is registered at the fourth floor by operation of the push button 4U. This connects the up call storing relay 4UR for energization. The relay thereupon closes its make contacts 4UR1 to establish a holding circuit around the push button 4U. The call thereafter remains registered until the elevator car A or B stops at the fourth floor while set for travel in the up direction.

Let it be assumed that the elevator car A while set for travel in the up direction stops at the fourth floor. As the elevator car A nears the fourth floor, the following cancelling circuit is completed:

L+3, 4UR1, 4URN, d4, 34, P3, W3, M5, L3

The energized cancelling coil 4URN neutralizes the coil of the relay 4UR and the relay resets to open its make contacts 4UR1.

Figure 4 Circuits are illustrated for controlling the high car-call relay H, the car-call stopping relay T, the by-pass relay P, the first high floor-call relay K, the second high floorcall relay KX and the reversing relay J.

The upper part of Fig. 4 shows circuits for controlling the high car-call relays and the car-call stopping relays. Each of the car-call push buttons be and 2a to Sc normally is open. However, when pressed, each button is held in its pressed condition until the elevator car reverses its direction of travel. Thus, each of the buttons may be constructed of magnetic material, and when pressed, may be maintained in its pressed condition by means of a holding coil bee and 2cc to See. The prefixes b and 2 to 5 of these reference characters designate the respective floors with which the components are associated. The holding coils are connected in series across the buses L+3 and L3, either through make contacts W5 or through make contacts X6 of the preference relays. These contacts both are momentarily open to reset the car-call push buttons when the elevator car reverses its direction of travel.

Each of the car-call push buttons for the intermediate floors when operated connects two contact segments to the bus L+3. Thus, the car-call push button 20, when pressed, connects the contact segments a2 and M to the bus Ll-3. The elevator car does not have passengers desiring the fifth floor during down travel, and consequently only the one contact segment :15 for the fifth floor need be connected directly to the bus LI-3. Similarly only one contact segment hb for the basement floor is connected directly to the bus L+3. The push button 50 is employed only in the circuit for controlling the high car-call relay H.

The contact segments al to 05 and the contact segments hb and hl to h4 are mounted in two rows on the selector 16 of Fig. 1. As the elevator car moves upwardly the brush 31, which is mounted on the selector carriage 17 (Fig. l) successively engages the contact segments al to a5 as the car nears respectively the first to fifth floors. In a similar manner as the car moves down from the fifth floor the brush 43 successively engages the contact segments k4 to I11 and hb as the car nears respectively the fourth to first and basement floors.

If the elevator car A is traveling up, and if a car call is registered. for the fourth floor, the brush 31 engages the contact segment a4 a predetermined distance in advance of the fourth floor to energize the car-call stopping relay T through the circuit:

LI- 3, 40, a4, 31, W4, T, M6, L3

The car-call stopping relay then initiates a stopping operation of the elevator car. The parts may be so related that the brush 31 leaves the contact segment shortly before the elevator car comes to a full stop.

If the elevator car A were traveling down with a passenger to be discharged at the fourthfioor, the following circuit would be completed as the elevator oar nears the fourth floor:

Ll-3, 40, I14, 43, X5, T, M6, L3

Consequently, the car-call stopping relay T again would be energized to initiate the stopping operation of the elevator car A at the fourth floor. The parts may be so related that the brush 43 leaves the contact segment I14 shortly before the elevator car comes to a full stop.

Ill

The push button be controls through its contacts 1702 the energization of the relay Xla (Fig. 2). When operated the push button opens its contacts [201 to open an alternate energizing circuit for the contact segments a1 and hl.

The high car-call relay H when energized indicates the presence of a registered car call for a floor above the position of the elevator car. The mechanical switches 52 to 55 are employed in controlling the energization of this high car-call relay. It will be noted that one of the mechanical switches is connected across each successive pair of contact segments. The mechanical switches connected to the contact segments corresponding to the position of the elevator car or to the floor directly below the elevator car are opened by the cam 49 to prevent energization of the high car-call relay H through car-call push buttons for the lower floors, and to prevent energization of the car-call stopping relay except through the push button for the floor which the elevator car is nearing. However, if any car-call push button is pressed for a floor above the position of the elevator car, a circuit is completed for the high car-call relay H through the intermediate mechanical switches. Thus, with the elevator car at the third floor, if a car call is registered for the fifth floor, the following circuit would be completed:

L+3, c, 55, a4, 30, H, L3

The car-call circuits are standard in the art. The brush 30 is mounted on the carriage 17 of Fig. l and is long enough to bridge the space between adjacent contact segments of the row all to a5.

The switch PB is mounted in the elevator car and is closed to energize the by-pass relay P when the elevator car is to run express. The switch may be held in operated position by means of a holding coil in the same manner by which the car-call push buttons are held in pressed conditions. However, the switch PB may be of the type which returns to its unoperated condition as soon as it is released by the person who pressed it. If desired the switch iB may be a load-responsive switch which is normally open, and which is closed when the elevator car load reaches a predetermined value.

The first high floor-call relay K when dropped out indicates the presence of a call registered by at least one of the up call-storing relays 2UR to 4UR, and the first down call-storing relays 2BR to SDR for a floor above the position of the elevator car. The energization of the relay is controlled through a call-above indicator circuit 56 which is common to all of the elevator cars. This call-above indicator circuit 50 has associated therewith a row of contact segments all to e5, respectively, for the first to fifth floors. The contact segments are mounted on the floor selector 16 of Fig. 1 and are engaged successively by the brush 35 which is mounted on the carriage 17 of the fioor selector as the elevator car A proceeds upwardly from the first floor. A corresponding contact segment for the elevator car B is connected to each of the contact segments for the elevator car A.

Break contacts 2UR2 to 4UR2 of the up call-storing relays and break contacts 2DR4 to 5DR4 of the first down call storing relays are connected in series in the call above indicator circuit 50 in the order clearly illustrated in Fig. 4. The contact segments 61 to 05 are connected to the call above indicator circuit St at points such that the contacts of all storing relays requiring travel of the elevator car above a floor are located above the point of connection of the contact segment in the e row for such floor. The connections are clearly illustrated in Fig. 4.

The second high floor-call relay KX when energized indicates the absence of a call for a floor above the position of the elevator car A registered by any of the relays 2UR to 4UR and ZDX to SDX. This relay is associated with a row of contact segments fit to f5, a brush 36 and a call above indicator circuit 50X in the same manner by which first high fioor-call relay K is associated with contact segments e1 to e5, the brush 35 and the indicator circuit 50. The call-above indicator circuits 54D and 50X are similar with the exception that in the call above indicator circuit 50X break contacts of the second down call-storing relays ZDX to SDX are employed respectively in place of the break contacts of the first down callstoring relays ZDR to SDR employed in the circuit 543.

By inspection of Fig. 4 it will be noted that the first high floor-call relay K can be energized only if the break contacts SW1 of a second wave relay are closed. The second high floor-call relay KX can be energized only if the break contacts FWl of a first wave relay are closed.

When the elevator car A is traveling up, energization of the reversing relay I initiates the stopping and reversing of the elevator car at the next fioor reached by the elevator car. The relay I can be energized only if the break contacts H1 are closed to indicate that no car call is registered for a floor above the position of the elevator car. In addition, one of the sets of make contacts KXl or K1 must be closed. The make contacts KXll are closed it no call is registered for a floor above the position of the elevator car by the up call-storing relays 2UR to 4UR or by the second down call-storing relay ZDX to SDX. In addition, the relay KX can be energized only if the elevator car is assigned to answer calls registered by the second down call storing relays ZDX to SDX (contacts FWll are closed).

The first high floor-call relay K picks up to close its make contacts K1 if the elevator car A is assigned to answer calls registered by the first down call storing relays 2DR to SDR (contacts SW1 are closed) and if no call is registered for a floor above the position of the elevator car by any of the first down call-storing relays 2DR to SDR or any of the up call storing relays EUR to 4UR.

When the reversing relay I picks up, it closes its make contacts J4 to establish a holding circuit around the make contacts KXI and K1. In addition, make contacts J3 close to establish with break contacts DRZ of the door safety relay DR a holding circuit around the make contacts W8 of the up-direction preference relay W. Inasmuch as the elevator car doors customarily start to open well in advance of arrival of the elevator car at a floor at which it is to stop, it follows that the break contacts DR2 close before the make contacts W8 open.

Figure 5 In Fig. 5 circuits are illustrated for controlling the floor call stopping relay S, the first wave relay PW, the second wave relay SW and the transfer control relay Q. In addition, a circuit is illustrated for controlling the operation of signal lights located in the elevator cars for the purpose of indicating that an elevator car should proceed to an extension floor which in this case is the basement floor.

If the elevator car A is set for travel in the down direc tion, the make contacts X7 of the down direction preference relay X are closed to connect the floor call stopping relay S through the break contacts P4 of tl e by-pass relay between the bus L-3 and a brush 37 which is mounted on the carriage 17 of Fig. l. The brush 37 cooperates with a row of contact segments g2 to g5 which are located on the floor selector 16 of Fig. 5. As the elevator car A proceeds in the down direction from the fifth floor, the brush successively engages the contact segments g5 to g2. A corresponding contact segment for each of the remainder of the elevator cars in this case the elevator car B is connected to each of the contact segments g2 to g5.

If the elevator cars are assigned to answer a first group of calls represented by the first down call-storing relays ZDR and 5DR, the make contacts FWZ of the first wave relay PW are closed. Under these circumstances, make contacts 2DR5 to SDRS are effective respectively for connecting the contact segments g2 to g to the bus L3. If a down floor call is registered for example at the third fioor by the relay SDR, the make contacts 3DR5 are closed and as the elevator car A nears the third floor in the down direction, the brush 37 engages the contact segment g3 to establish the following circuit:

The energized floor-call stopping relay S then initiates the stopping operation of the elevator car at the third floor. Astthe elevator car stops, the brush 37 may pass slightly beyond the contact segment g3.

If the elevator cars are assigned to answer a second group of calls represented by the second down call storing relays 2DX5 to SDXS, the make contacts SW2 of the second wave relay SW are closed, Under these circumstances, the make contacts 2DX5 to SDXS of the second down call-storing relays are effective for connecting respectively the contact segments g2 to g5 to the bus L+3. If a down floor call at the third floor has resulted in closure of the make contacts SDXS, the down traveling elevator car A as it nears the third floor, causes the brush 37 to engage the contact segment g3 and the following circuit is completed:

L+3, SW2, 3DX5, g3, 37, X7, P4, S, L3

The energized floor-call stopping relay S then initiates a stopping operation of the elevator car A at the third floor.

If the elevator car A is set for up travel, the floor-call stopping relay S is connected through the make contacts W9 and the break contacts P4 between a brush 38 and the bus L-3. The brush 38 and a row of contact segments 122 to I14 aremounted on the floor selector 16 of Fig. 5. As the elevator car A proceeds upwardly from the lower terminal floor, the brush 33 successively engages the contact segments k2 to A similar contact segment for each of the remainder of the elevator cars, in this case the elevator car B, is connected to each of the contact segments h2 to M.

The contact segments k2 to I14 are connected to the bus L-l-3 respectively through make contacts 2UR4 to 4UR4 of the up call-storing relays ZUR to EUR. If an up call for elevator service is registered at the third floor, the make contacts 3UR4 are closed. Under these circumstances, if the elevator car A while traveling up approaches the third fioor, the contact segment k3 is engaged by the brush 38 to complete the following circuit:

L+3, 3UR4, h3, 33, W9, P4, S, L-3

The energizedfloor-call stopping relay S then initiates a stopping operation of the elevator car A at the third floor. As the elevator car stops, the brush 38 may pass slightly beyond the contact segment 113.

The first wave relay PW can be energized only if the break contacts SW3 are closed to indicate that the second wave relay SW is deenergized. Under these circumstances, closure of any of the parallel make contacts 2DR6 to 5DR6 of the first down call-storing relays completes an energizing circuit for the first wave relay.

The second wave relay SW can be energized only if the break contacts FWS are closed to indicate that the first wave relay FW is deenergized. Under these circumstances, closure of any of the parallel make contacts 2DX6 to 5DX6 of the second down call-storing relays ZDX to SDX completes an energizing circuit for the second wave relay SW.

If a floor call is registered at the basement floor, the make contacts bUR4 are closed for the purpose of operat ing a signal such as a lamp L located in the elevator car A for the purpose of indicating the presence of the registered floor call at the basement floor. It the elevator system is completely automatic and has no car attendants the signal may be a relay for assigning the associated elevator car if available for travel to the basement floor.

The signal or lamp L can be operated under these circumstances only if the break contacts Xlal are closed to indicate that no car call is registered in the elevator car A for the basement floor, and if similar-break contacts for the remainder of the elevator cars are also closed to indicate that no car call for the basement floor is registered-in any of the elevator cars. Thus, in the'present case. to illuminate the lamp L, the seriesmake contacts bUR4, Xlal and BXltal all must be closed.

A separate signal for each of the remainder of the elevator cars is connected for energization with the signal L. In the present case, a lamp BL for the elevator car B is connected in parallel with the lamp L.

If the switch 74 is closed, the transfer control relay Q is connected across the buses L+3 and L-3 permanently for energizationv If the switch 74 is open, the energization of the relay is controlled by the registration of calls by the downcall-storing relays.

By inspection of Fig. 5 it will be observed that the relay Q is connected across the buses L+3 and L3 through four parallel circuits each including a separate one of make contacts 2DR7 to 5DR7 for the first down call-storing relays ZDR. to SDR. In addition, each of the arms includes in series one of the resistors 2R3 to 5R3.

The parameters of the circuit are selected to require closure of a predetermined number of the make contacts 2DR7 to.5DR7' before the transfer control relay Q is picked up. The parameters also are selected to permit dropout of the relay Q when the number of closed make contacts 2DR7' to 5DR7-falls below a predetermined value.

When it picks up, the relay Q closes its make contacts Q5 to completea holding circuit for the relay through any one of theparallel make contacts 2DX7 to SDX] of the seconddown call-storing relays ZDX to SDX.

OPERATION Certain operations of the elevator system now will be considered. It will be assumed initially that both the elevator cars are at the lower terminal or first floor set for up travel. For the elevator car A, the up direction preference relay W is energized and picked up.

At this stage it will'beassumed that down floor calls are registered at the third, fourth and fifth floors; The down floor call at the fifth floor is registered by operation of the push button 5D (Fig. 3) to complete the following circuit:

L+3, SD, 581, SDXl, SDR, L-3

The relay SDR closes its make contacts 5DR1 to establish a holding circuit around the push button 5D and the break contacts 581 of the down call-control relay for the fifth floor. Opening of break contacts 5DR2 has no immediate effect on the operation of the system. Closure of the make contacts SDRS prepares the down call-control relay 58 for subsequent energization. Opening of the break contacts 5DR4 (Fig. 4) prevents energization of the first high floor-call relay K until the elevator car reaches the fifth floor. Closure of the make contacts 5DR5 (Fig. 5) prepares the contact segment g5 for connection to the bus L-l-Zt. Closure of the make contacts5DR6 completes with the break contacts SW3 an energizing circuit for the first wave relay FW. Closure of the make contacts 5DR7 completes a partial energizing circuit for the relay Q. The switch 74 is assumed to-be open. The partial energization of the relay Q is assumed to be insutficient to pick up the relay.

Inasmuch as the first wave relay PW is now energized, the break contacts FWI (Fig. 4) are open to prevent energization of the second high floor-call relay KX. Make contacts PW2 (Fig. 5) are closed to render efiective the make contacts ZDRS to 5DR5 for controlling a stopping operation of the elevator cars. Opening of break contacts FW3 prevents energization of the second wave relay SW.

Registration of the down floor call for the fourth floor is effected by operation of the push button 4D (Fig. 3). This operates in a manner similar to the operation of the push button 5D to complete an energizing circuit for the first down floor-call storing relay 4DR and the relay closes its make contacts 4DR1, 4DR3, 4DR5 (Fig. 5), 4DR6 and 4DR7, and opens its break contacts 4DR2 (Fig. 3) and 4DR4 (Fig. 4). These contact operations have no immediate effect on the operation of the system with the exception that the closure of the make contacts 4DR7 establishes a second energizing path for the transfer control relay Q. It will be assumed that the transfer control relay Q picks up when it is energized through at least two of the resistors 2R3 to 5R3 and that it remains picked up until all of the calls have been answered.

The energization and pickup of the transfer control relay Q results in closure of the make contacts Q5 without immediate effect on the operation of the system. In addition, make contacts Q2 to Q4 (Fig. 3) close. Closure of the make contacts Q1 completes with the closed make contacts 5DR3 and the closed break contacts 5DX3 an energizing circuit for the down call-control relay 58 for the fifth floor. This relay opens its break contacts 551 and closes its make contacts 582 without immediately affecting the operation of the system. Closure of the make contacts 583 establishes a holding circuit around the make contacts 5DR3.

In a similar manner closure of the make contacts Q2 results in energization of the down call-control relay 48 for the fourth floor, which closes its make contacts 482 and 483 and opens its break contacts 481.

The registration of the down floor call for the second floor by operation of the push button 2D similarly results in energization of the first down call-storing relay 2DR for the second floor and of the down call-control relay 28 for the second floor. The relay ZDR closes its make contacts 2DR1, 2DR3, 2DR5 (Fig. 5), 2DR6 and 2DR7, and opens its break contacts 2DR2 (Fig. 3) and 2DR4 (Fig. 4). The relay 28 opens its break contacts 281 and closes its make contacts 282 and 253.

The car attendant in the elevator car A now closes his doors and such closure results in energization and pickup of the door safety relay DR. This relay closes its make contacts (Fig. 2) and opens its break contacts (Fig. 4) Without immediately affecting the operation of the system.

Next the car attendant rotates his car switch CS to complete the following circuit:

L-I-3, CS, CS1, VVl, F1, STU, U, M, DRl, L-3

Closure of the make contacts U1 of the up switch U releases the elevator brake 15. Closure of make contacts U2 and U3 completes an energizing circuit for the generator field winding GF with proper polarity for up travel of the elevator car through the resistor R1. Closure of make contacts U4 completes with the limit switch VTU and the break contacts E1 an energizing circuit for the speed relay V and this relay closes its make contacts V1 to shunt the resistor R1 and condition the elevator car A for full speed travel in the up direction. The speed relay V also opens its break contacts V2 without immediately affecting the operation of the system.

Closure of make contacts U5 establishes a holding circuit around the car switch CS and the make contacts W1 of the up direction preference relay W. Opening of the break contacts U6 has no immediate efiect on the operation of the system.

The car running relay M upon being energized closes its make contacts M1 and M2 without immediately affecting the operation of the system. In addition, break contacts M3, M4 and M5 (Fig. 3) open without immediately affecting the operation of the system. Make 16 contacts M6 (Fig. 4) close without immediately affecting the operation of the system.

As the elevator car nears the fifth floor, the brush 31 (Fig. 4) engages the contact segment a5 to complete with the make contacts W4 and M6 an energizing circuit for the car-call stopping relay T. This relay closes its make contacts Tll (Fig. 2) to complete with the make contacts M1 an energizing circuit for the inductor holding relay G and the slowdown inductor relay E.

At this time, the brush 35 (Fig. 4) engages the contact segment 25 to establish with the contacts W6 and SW1 an energizing circuit for the first high floor-call relay K. This relay closes its make contacts K1 to complete with the contacts H1 and W3 an energizing circuit for the reversing relay I. The reversing relay closes its holding contacts I3 and J4. In addition, the reversing relay closes its make contacts I1 (Fig. 2). Since these contacts are in parallel with contacts T1, closure of either of the sets of contacts is effective for energizing the relays E and G. Opening of the break contacts I2 has no immediate effect on the operation of the system.

As the elevator car A continues its approach to the fifth floor, the slowdown inductor relay E reaches the inductor plate UEP (Fig. 1) for the fifth floor and opens its break contacts E1 to deenergize theh speed relay V (Fig. 2). The speed relay opens its make contacts V1 to insert the resistor R1 in series with the generator field Winding and the elevator car A consequently slows to a landing speed. In addition, the speed relay closes its break contacts V2 to energize the relay F but without immediately affecting otherwise the operation of the system.

Upon continued movement of the elevator car towards the fifth floor, the stopping inductor relay F (Fig. 1) reaches the inductor plate UFP for the fifth floor, and opens its break contacts F1 to deenergize the up switch U and the car running relay M (Fig. 2).

The up switch U opens its make contacts U1 to apply the brake 15 and opens its make contacts U2 and U3 to deenergize the generator field winding GF. Consequently, the elevator car A stops accurately at the fifth floor. Opening of the make contacts U4 and U5 and closure of the break contacts U6 have no immediate effect on the operation of the system.

The car running relay M opens its make contacts M1 to deenergize the relays G, E and F. The opening of the make contacts M2 or the opening of the limit switch 3tPT as the elevator car A reaches the fifth floor results in deenergization of the up direction preference relay W. The closure of the break contacts M3 (Fig. 3), M4 and MS has no immediate effect on the system. Opening of the contacts M6 (Fig. 4) deenergizes the car call stopping relay T. As the elevator car stops the brush 31 may pass slightly beyond the contact segment a5.

Upon dropping out the tip-direction preference relay W opens its make contacts W1 (Fig. 2), W3 (Fig. 3), W4 (Fig. 4), W7, W8 and W9 (Fig. 5) without immediately affecting the operation of the system. Inasmuch as the door started to open prior to drop out of the up-direction preference relay, the break contacts DRZ (Fig. 4) are closed to complete a holding circuit before the contacts W8 open.

As the elevator car left the lower terminal or first floor, the limit switch 393 (Fig. 2) reclosed. Consequently, closure of the break contacts W2 completes the following circuit:

L+3, U6, W2, 21B, X, 3013, R2, L-3

The down direction preference relay X now is energized and closes its make contacts X1 and opens its break contacts X2 without immediate effect on the operation of the system. Since the brush 32 (Fig. 3) is now in engagement with the contact segment b5, closure of the make contacts X3 completes the following cancelling circuit for the fifth floor:

1 7 1+3, on1, 59x1, SDRN, b5, 32, M3, X3, P1, L-3

Closure of make contacts X4, X5 (Fig. 4), X6 and X7 (Fig. 5) has no immediate effect on the operation of the system.

As a result of its energization the cancelling coil SDRN (Fig. 3) neutralizes and resets the first down floor-call storing relay 5DR. This relay opens its make contacts 5DR1 and 5DR3 and closes its break contacts SDRZ without immediate effect on the operation of the system. Closure of break contacts 5DR4 (Fig. 4) and opening of make contacts SDRS, 5DR6 and 5DR7 (Fig. 5) have no immediate effect on the operation of the system.

It is assumed neXt that the passenger at the fifth floor enters the elevator car and the elevator car attendant closes his doors to energize the door relay DR. This relay closes its make contacts DR1 and opens its break contacts DR2 (Fig. 4). The opening of the break contacts DRQ; deenergizes the reversing relay I which opens its holding contacts J3 and 14, opens its make contacts J1 (Fig. 2) and closes its break contacts J2 without immediate effect on the operation of the system.

The car attendant now closes his car switch CS to complete the following circuit:

L+3, CS, CS1, X1, F2, STD, D, M, DR1, L-3

The down switch D closes its make contacts to release the brake 15. Contacts D2 and D3 close to energize the generator field winding with proper polarity for the down travel of the elevator car. Make contacts D4 close to energize the speed relay V. This relay closes its make contacts V1 to shunt the resistor R1. The elevator car now is energized for full speed travel in the down direction. Break contacts V2 open without immediate effect on the operation of the system.

Make contacts D5 close to establish a holding circuit around the car switch CS and the make contacts X1. Opening of the break contacts D6 has no immediate effect on the operation of the system.

The car running relay M when energized close its make contacts M1 and M2, Opens its break contacts M3 (Fig. 3), M4 and M5, and closes its make contacts M6 (Fig. 4) without immediate effect on the operation of the system.

As the elevator car A approaches the fourth floor, the brush 37 (Fig. 5) engages the contact segment g4 to establish the following circuit:

As a result of its energization, the floor-call stopping relay S closes its make contacts S1 (Fig. 2) to complete with the contacts M1 an energizing circuit for the holding relay G and the slowdown inductor relay E. The holding relay G closes its make contacts G1 to establish a holding circuit around the make contacts S1.

Continued motion of the elevator car A brings the slowdown inductor relay E adjacent the inductor plate DEP (Fig. 1) for the .fourth floor and the break contacts E2 open to interrupt the energizing circuit for the speed relay V (Fig. 2). The speed relay opens its make contacts V1 to introduce the resistor R1 in series with the generator field winding GF and the elevator car A slows to its landing speed. Closure of the break contacts V2 completes an energizing circuit for the stopping relay F.

Further movement of the elevator car A brings the stopping inductor trelay F adjacent the inductor plate DFP (Fig. 1) for the fourth floor and break contacts F2 open to deenergize the down switch D (Fig. 2) and the running relay M.

The down switch D opens its make contacts to apply the brake 15 and the make contacts D2 and D3 open to deenergize the generator field winding GF. The elevator car now stops at the fourth floor.

Opening of the make contacts D4 and D5 and closure of the break contacts D6 have no immediate effect on the operation of the system.

The car running relay M opens its make contacts M1 to deenergize the inductor holding relay G and the inductor relays E and F. Opening of make contacts M2, closure of break contacts M4 (Fig. '3) and M5, and opening of make contacts M6 (Fig. 4) have no effect on the immediate operation of the system. However, as the elevator car A reaches the fourth floor, the brush 32 engages the contact segment b4 to establish the following cancelling circuit:

L+3, 4DR1, 4DX1, 4DRN, b4, 32, M3, X3, P1, L3

The energized cancelling coil 4DRN resets the first down call-storing relay 4DR.

On dropping out, the first down call-storing relay 4DR opens its make contacts 4DR1, closes its break contacts 4DR2 and opens its make contacts 4DR3 without immediate effect'on the operation of the system. Closure of the break contacts 4DR4 (Fig. 4) also has no effect on the operation of the system. Opening of the break contacts 4DR5 (Fig. 5), "4DR6 and 4DR7 has no effect on the operation of the system. It is assumed that the decrease in energization of the transfer control relay Q is insufiicient to cause this relay to drop out. As the elevator car stops, the brush 37 may pass slightly beyond the contact segment g4 (Fig. 5).

The elevator car attendant now opens his doors and deenergizes the door safety relay DR which opens its make contacts DR1 (Fig. 2) and closes its break contacts DR-2 (Pig. 4) without effect on the immediate operation of the system.

After the passenger at the fourth floor has boarded the elevator car, the car attendant closes his doors and proceeds from the fourth floor in the same manner by which he started the elevator car from the fifth floor.

It will be assumed that as the elevator car A leaves the fourth floor, a prospective passenger at the fourth floor operates the push button 4D (-Fig. 3) to reregister the call for the fourth floor. Such operation of the push button completes the following circuit:

The energization of. the second down floor-call storing relay 4DX results in opening of the break contacts 4DX1 without affecting the operation of the system. Make contacts 4DX2 close to establish :a holding circuit around the push button 4D and the make contacts 482. Break contacts 4DX3 open to deenergize the down call-control relay 4S. Break contacts '4DX4 open without immediately affecting the operation of the system. In addition, make contacts 4DX5 (Fig. 5), =4DX6 and 4DX7 close without immediately affecting the operation of the system.

It should be noted that whereas the first call from the fourth floor was registered by energization of the first down call-storing relay 4DR, the second or reregistered call for the fourth floor was registered by energiz-ation of the second down call-storing relay 4DX.

The elevator car A proceeds in the down direction and stops to answer the third floor call registered by the first down call-storing relay 3DR in 'a manner which will be clear from the previous discussion of the answering of the down floor call at the fourth floor. It will be assumed that the elevator car is sufficiently loaded at the third floor and that the car attendant operates the switch PB to energize the by-pass relay P. This conditions the elevator car to express to the first floor.

The elevator car A is started from the third floor by a sequence which will be clear from the previous discuss-ion of the starting of the elevator car from the fifth floor. As the elevator car star-ts, it will be assumed that a prospective passenger at the third floor reregisters a down floor call by operating the push button 3D. The reregistration of the call at the third floor results in energization and pick up of the second down call-storing relay BDX and this relay opens its break contacts 3DX1, closes its make contacts 3DX2, opens its break contacts 3DX3 to deenergize the down call control relay 38, opens its 3.3 break contacts 3DX4 (Fig. 4) and closes its make contacts 3DX5 (-Fig. 3DX6 and 3DX7. The down call control relay 3S closes its break contacts 381 and opens its make contacts 382 and 383.

As the elevator car A stops for the third floor call, it will be assumed that a call is registered at the second floor by operation of the push button Z'D ('Fig. 3) to establish the following circuit:

L+ 3, 2D, 2S1, 2DX1, ZDR, L-3

In the manner previously discussed for the fifth, the relay ZDR closes its make contacts ZDRI, opens its break contacts 2DR2, closes its make contacts 2DR'3 to complete an energizing circuit for the down call-control re- =lay 2S, opens its break contacts 2DR4 (\Fig. 4) and closes its make contacts ZDRS (Fig. 5), 2DR6 and 2DR 7. The contacts 2DR6 retain relay FW picked up. The down call-control relay 28 (Fig. 3) opens its break contacts 281 and closes its make contacts 252 and 283.

The call for the second floor is by-passed by the elevator car A during its return to the lower terminal or first floor as contacts P4 (Fig. 5) are open which prevents relay S from being energized. However, as the elevator car A approaches the first floor, it is assumed that the elevator car B is started from the first floor in the up direction by a sequence which will be clear from the preceding discussion of the starting of the elevator car A from the first floor.

As the elevator car A nears the first floor, the brush 43 (Fig. 4) engages the contact segment hll to complete the following circuit:

L+3, bcl, I11, 43, X5, T, M6, L-3 The energized car-call stopping relay T closes its make contacts T1 to energize the relays G, E and F (Fig. 1) for the purpose of stopping the elevator at the first floor by a sequence which will be clear from the discussion of the stopping of the elevator car at the fourth floor.

As the elevator car A stops at the first floor, the limit switch 303 opens to deenergize the down-direction preference relay X. This relay opens its make contacts XI, closes its break contacts X2 to complete an energizing circuit for the up-direction preference relay W as the car stops, opens its make contacts X3 (Fig. 3), X4, X5 (Fig. 4), X6 and X7 (Fig. 5). The deenergization of the down-direction preference relay X and the energization of the up-direction preference relay W results in setting of the elevator car A for up travel. The switch PB (Fig. 4) is reset to deenergize the bypass relay P and to permit the elevator car to answer calls registered from the floors.

Turning now to the elevator car B, it will be assumed that as the elevator car B leaves the first floor, a car call for the third floor is registered by operation of the push button B30 (Fig. 4). When operated the push button is held in operated position by the holding coil B366.

At this stage, four calls are registered on the system. These calls are represented by the energized second down call-storing relays 4DX and 3DX for the fourth and third floors, the energized first down call-storing relay 2DR for the second floor, and the operated push button B30 which registers a car call for the third floor.

By reference to Fig. 5 it will be noted that the make contacts SW2 of the second wave relay SW are still open. Consequently, the calls registered by the second down call-storing relays 3DX and 4DX are inefiective for en ergizing the floor-call stopping relay S.

When the car call for the third floor was registered, the elevator car B was adjacent the first floor. For this reason the high car-call relay BH was energized through the circuit:

L+3, B3c, B53, Ba2, B30, BH, L-3 This relay thereupon opens its break contacts BHI to prevent energization of the reversing relay B].

2B As the elevator car B approaches the second floor, the brush B35 in Fig. 4 engages the contact segment Be2 to complete the following circuit:

The relay BK thereupon closes its make contacts BKl. However, since the contacts BHl are open, the reversing relay BJ cannot be energized to reverse the elevator car B at the second floor.

As the elevator car B nears the third floor, the brush B31 engages the contact segment B23 to complete the following circuit:

L+3, B30, Ba3, B31, BW4, BT, BMG, L3

The energized car-call stopping relay BT closes its make contacts BTl (Fig. 2) to complete with the contacts BMI an energizing circuit for the holding relay BG and the slowdown inductor relay BE. These relays cooperate to initiate a stopping of the elevator car at the third floor by a sequence which will be clear from the preceding discussion of the stopping of the elevator car A at the fifth floor.

It should be noted further that as the elevator car B nears the third floor, the brush B30 (Fig. 4) engages the contact segment B514 which is isolated from the push button B3c as a result of the opening of the switch B54 by the cam B49. Consequently, the high car-call relay BH drops out to close its break contacts BHl. Since the contacts BHl, BKI and BWS all are now closed, the reversing relay B] is energized and closes its holding contacts B] 3 and B14. In addition, the reversing relay closes its make BJl (Fig. 2). Since these contacts are in parallel with the contacts BTl, closure of either set is etfective to initiate a stopping of the elevator car B at the third floor.

The reversing relay also opens its break contacts BJZ. Inasmuch as the make contacts BM2 open as the elevator car B stops, the up-direction preference relay BW is deenergized. As a result of its deenergization, the updirection preference relay closes its break contacts BW2 to complete an energizing circuit for the down direction preference relay BX. The elevator car B is now set for down travel at the third floor.

Immediately after the up-direction preference relay BW drops out, the make contacts BW5 and BX6 (Fig. 4) momentarily are both open. Such opening deenergizes the holding coil 133cc and consequently the push button B3c is reset to its open condition.

The car attendant now opens the doors of his elevator car to discharge his passenger, recloses his doors and starts the elevator car B down from the third floor by a sequence which will be clear from the discussion of the starting of the elevator car A from the fifth floor.

It should be noted that although the stopping of the elevator car B at the third floor was in response to a registered car call rather than the call registered by the second down call-storing relay 3DX (Fig. 3), the latter call also is cancelled. Such cancelling takes place because the brush B33 is in engagement with the contact segment B03 and when the down direction preference relay picks, the following cancelling circuit is completed:

L+3, 3DX2, 3DR2, 3DXN, Bc3, B33, BM4, BX4, BPZ, L3

The energized cancelling coil 3DXN resets the second down call-storing relay 3DX in a manner which will be clear from the preceding discussion.

It should be noted further that although a call is registered by the second down call-storing relay 4DX for a floor above the position of the elevator car, such call is ineffective for controlling the operation of the elevator car B for the reason that as long as the first wave relay FW is energized, the elevator cars A and B are conditioned to answer only registered car calls, registered 21 up floor calls and down floor calls registered by the first down call-storing relays ZDR to SDR.

As the elevator car B during its return to the first floor nears the second fioor, the brush 37 (Fig. engages the contact segment g2 to complete the following circuit:

The energized floor-call stopping relay BS initiates a stopping operation of the elevator car B at the second floor by a sequence which will be clear from the preceding discussion of the stopping of the elevator car A at a floor.

As the elevator car B stops at the second floor, the brush B32 engages the contact segment B122 to complete the following cancelling circuit:

L+3, ZDRI, 2DX1, ZDRN,

Bb2, B32, BM3, BX3, BPl, L-3

The energized cancelling coil 2DRN resets the call-storing relay ZDR which opens its make contacts 2DR1 and 2DR3, closes its break contacts 2DR2 and 2DR4 (Fig. 4) and opens its make contacts 2DR5 (Fig. 5), 2DR6 and 2DR7.

All of the calls registered by the first down call-storing relays 2BR to SDR have now been answered. Consequently, all of the make contacts 2DR6 to 5DR6 are now open and the first wave relay FW is deenergized. This relay closes its break contacts FWl (Fig. 4) to condition the second high floor-call relay KX for subsequent operation. Make contacts FW2 (Fig. 5) open to render ineffective the make contacts 2DR5 to SDRS. Finally, break contacts FW3 close to permit energization of the second wave relay SW.

Inasmuch as a call remains registered for the fourth floor by the second call-storing relay 4DX, the make contacts 4DX6 remain closed and with the closed break contacts FW3 complete an energizing circuit for the second wave relay SW. This relay opens its break contacts SW1 (Fig. 4) to remove the first high floor-call relay K from service. Make contacts SW2 (Fig. 5) close to render effective the contacts ZDXS to SDXS. Break contacts SW3 open to render ineffective the first wave relay FW.

Inasmuch as the make contacts 4DX7 continue to be closed, the transfer control relay Q continues to be energized through the holding contacts 4DX7 and Q5.

The elevator cars now are conditioned to answer calls in the second group which are registered by operation of the second down call-storing relays ZDX to SDX.

It will be assumed that as the elevator car B returns to the first floor, the elevator car A is started by its car attendant from the first fioor in the up direction by the sequence previously discussed. As the elevator car A nears the fourth floor, the brush 36 (Fig. 4) engages the contact segment f4 to complete the following circuit:

L+3, 5DX4, 4UR3, f4, 36, W7, KX, FWI, L3

The closure of contacts KXl completes with the contacts H1 and W8 an energizing circuit for the reversing relay I which closes its holding contacts J3 and J4, and closes its make contacts 11 (Fig. 2) to initiate a stopping operation at the fourth floor by a sequence which will be clear from the above discussion.

The reversing relay also opens its break contacts J2. As the elevator car A stops at the fourth fioor, the make contacts M2 open to deenergize the rip-direction preference relay W. In dropping out, the rip-direction preference relay closes its break contacts W2 to complete an energizing circuit for the down direction preference relay X. Consequently, the elevator car A now is set for travel in the down direction.

By reference to Fig. 3, it will be noted that when the down-direction preference relay X picks up, make contacts X4 are closed to complete the following cancelling circuit:

22 L+3, 4px;, 4on2, 4DXN, c4, 33, M4, X4, P2, L-3

The cancelling coil 4DXN resets the relay 4DX and this relay closes its break contacts 4DX1, opens its make contacts 4DX2, closes its break contacts 4DX3, closes its break contacts 4DX4 (Fig. 4), opens its make contacts 4DX5 (Fig. 5), 4DX6 and 4DX7.

If no other call for service is registered by any of the second call storing relays 2DX to SDX, the contacts 2DX6 to 5DX6 are all open and the second wave relay SW now is deenergized. This relay thereupon closes its break contacts SW1 (Fig. 4), opens its make contacts SW2 (Fig. 5) and closes its break contacts SW3 without immediately affecting the operation of the system.

If no other call for service is registered, the opening of the make contacts 4DX7 deenergizes the transfer control relay Q. This relay opens its make contacts Q1 (Fig. 3), Q2, Q3, Q4 and Q5 (Fig. 5) without immediately affecting the operation of the system.

After accepting the load at the fourth floor, the elevator car attendant may return his elevator car to the first floor by the sequence previously discussed.

If a down floor call is again reregistered at the fourth fioor as the elevator car A departs therefrom, the operation of the push button 4D (Fig. 3) establishes with the contacts 451 and 4DX1 an energizing circuit for the first down call-storing relay 4DR. In this way, successive down fioor calls for any fioor may be stored alternately by the first and second call-storing relays for the floor, and the elevator cars may be assigned alternately to respond to calls registered by the groups of down call-storing relays. Consequently, no intending passenger is forced to wait unduly long for service.

It will be understood that the elevator cars normally operate between the first and fifth floors which may be termed normal terminal or dispatching floors. The basement fioor may be termed an extension or sub-terminal floor.

It will be assumed next that the elevator cars A and B are both proceeding down towards the lower terminal or first floor when a call for the basement floor is registered by operation of the push button bU (Fig. 3). Such operation energizes the up call-storing relay bUR which closes its holding contacts bURl. In addition, make contacts bUR4 (Fig. 5) close.

If none of the elevator cars has a car call registered for the basement floor, the break contacts Xlal and BXlal are closed and an energizing circuit is established for the signal lamps L and BL to notify the car attendants that a passenger awaits service at the basement floor. Let it be assumed that the car attendant in the elevator car A accepts the assignment to the basement by operating his push button bc (Fig. 4). Such operation results in energization of the relay Xla (Fig. 2), and establishes a shunting circuit around the limit switch 303 and the resistor R2 The energized relay Xla opens its break contacts Xial (Fig. 5) to deenergize the lamps L and BL. This prompt deenergization of the lamps notifies the car attendant in the elevator car B that the call for service from the basement floor has been accepted by another elevator car and that it is unnecessary for the elevator car B to proceed to the basement floor. It

, should be noted further that had a car call for the basement floor been registered by the car attendant in the elevator car A prior to the request for service from the .basement fioor, the break contacts Xlal would have been open before the closure of the make contacts bUR4 and the lamps would not have been illuminated as a result of the registration of the call for service at the basement floor.

When the elevator car A reaches the first fioor, the limit switch 30B opens. However, since the limit switch now is shunted by the contacts 1202 and the relay Xla, the down-direction preference relay X remains energized

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