Elevator control system

Abstract

An elevator control system for a group of cars in which the control of the cars is transferred in response to traffic conditions from a mode of operation in which the cars are successively started from a terminal in response to the generation of timed dispatching signals to one in which they are started in response to the registration of calls. During the latter mode of operation the cars are distributed throughout that portion of the building they serve whereby one car is parked at the top terminal, one at a landing called the middle free car parking floor and the remainder at the bottom terminal. In these circumstances, the top terminal car serves calls at that landing, the middle free car serves calls at landings between the bottom and top terminals and one of the bottom terminal cars serves calls at that landing and at any basements below it.

The cars are capable of high and low call reversal at any landing and the assignment of the cars as middle free car and active bottom car can be transferred if the active bottom car travels above a certain landing.

Description

UDSa-7), WB2d-3 and MF1d-3. No circuit is completed for the upper coil of switch ABc as contacts MF1c-3 are separated. Thus car "d" is selected as the new active bottom car when car "c" is selected as the new middle free car. When car "a" arrives at the bottom terminal it becomes the inactive bottom car.

Should car "d" be out of service at the time that car "c" becomes the new middle free car, car "a" becomes the new active bottom car as it arrives at the bottom terminal. If for some reason car "a" fails to return to the bottom terminal when car "d" is out of service, the inactive top car "b" is caused to come to the bottom terminal and become the new active bottom car. This is effected by switch XCSa. Under the conditions assumed, if car "a" is answering calls at the time, either switch HJa or switch LJa acts to break the circuit for the coil of switch RAa. If not answering calls, switch LJa is operated as the main landing return circuit is set up, thus breaking the circuit for the coil of switch RAa. In either case, contacts RA2a-7 separate in the circuit for the coil of relay XCSa. This relay is delayed in dropping out for a certain time interval, say fifteen seconds, by the discharge of condenser Q2a-7. If the car fails to start or restart within that time and engage contacts H3a-7 to reconnect coil XCSa-7 to the supply lines, the relay drops out, removing car "a" from service. Inasmuch as contacts MR1a-3 are separated as a result of the main landing return circuit being set up, the separation of contacts XCS4a-3 as a result of the dropping out of relay XCSa breaks the circuit for the lower coil of switches ITb. Inasmuch as contacts ITC1-3 also are separated, switch ITb drops out to engage contacts IT4b-6, causing car "b" to discontinue being the inactive top car and to come to the bottom terminal to become the new active bottom car.

Assume as before that car "a" is the middle free car, that car "c" is the active bottom car and that car "a" is returned to the bottom terminal in response to a car call. As it arrives at that landing, brush MLBa-7 engages contact MLCa-7 to complete a circuit for the coil of switch MLa. This switch operates to engage contacts ML1a-3, completing a circuit through contacts MF5a-3 and UD1a-3 for the lower coil of switch XM. This switch operates and, as the direction is changed to up to cause the separation of contacts UD1a-3, drops out again. This momentary operation of switch XM causes changeover of the middle free car to car "c" as set forth above, with the result that car "c" goes to the middle free car parking floor. Either car "a" or car "d" is selected as the active bottom car as car "c" leaves the bottom terminal.

Should the middle free car fail to respond to a call within a certain time interval, it is automatically removed from service and another car becomes the middle free car. Assume that car "a" is the middle free car and is parked, and that a landing call is registered. This causes contacts RA2a-7 to separate, breaking the circuit for the coil of relay XCSa as above described. If the car fails to start and engage contacts H3a-7 to reconnect coil XCSa-7 to the supply lines within the time interval of relay XCSa, the relay drops out. As a result contacts XCS1a-3 separate to cause the dropping out of switch MFa, causing car "c" to become the middle free car and answer the call and car "d" to become the active bottom car, as above described. The same action is had when the middle free car is parked at the middle free car parking floor if someone touches a landing button at that floor and the doors fail to open within the given period. This is caused by the separation of contacts NT4a-7 which if they remain open for this period causes the dropping out of switch XCSa. As the call remains registered owing to the fact that contacts DCLa-5 and AS3a-5 are separated under the assumed conditions, as soon as car "c" becomes the new middle free car, it is started in the up direction to answer the call.

A similar operation is had if the doors of the active bottom car "c" fail to open within the given period after touching the landing button at the main landing. The resultant separation of contacts XCS2c-3 breaks the circuit for the lower coil of switch ABc and, as contacts ABC1-3 are separated, switch ABc drops out. Also contacts XCS1c-2 separate, breaking the circuit for the coil of relay VBc with the result that notching relay VUR selects car "d". As switch ABC drops out to engage contacts ABC1-3 as a result of the dropping out of switch ABc, the engagement of contacts WB2d-3 consequent upon the selection of car "d" causes the operation of switch ABd to select car "d" as the new active bottom car. So long as this car was the inactive bottom car, the touching of the button was ineffective to cause operation of switch NT for car "d" as contacts for car "d" corresponding to contacts ML1a-7 were separated. Upon becoming the active bottom car however, its contacts corresponding to contacts AB1a-7 are engaged so that the circuits are effective to open the doors for car "d".

Should, under the assumption where middle free car "a" is returned to the bottom terminal in response to a car call, or under the assumption where it fails to respond to a call within the time interval of relay XCSa, the active bottom car "c" fails to take the place of car "a", the new active bottom car, which will be car "d" where car "a" fails to respond and will be assumed to be car "d" where there is a selection between cars "a" and "d", is caused to take the place of car "c", and car "c" is removed from service. The failure of car "c" is signified by the dropping out of relay XCSc. The resultant separation of contacts XCS1c-3 breaks the circuit for the lower coil of switch MFc-3, causing this switch to drop out. This in turn causes the dropping out of switch MFC to engage contacts MFC3d-3 completing a circuit through contacts XM1-3, AB2d-3 and XCS1d-3 for the coil of switch MFd. Switch MFd operates to cause car "d" to become the new middle free car and thus to take the place of car "a".

When this operation takes place under conditions where car "a" failed to respond, inasmuch as there is no car left at the bottom terminal to become the new active bottom car and thus no switch AB is in operated condition, switch ABC is dropped out with the result that its contacts ABC3-3 separate to break the circuit for the coil of switch ABD. This switch is delayed slightly in dropping out by the discharge of condenser Q1-3 and upon dropping out engages contacts ABD2b-6 to complete a circuit through contacts IT3b-6 for the coil of switch LGb-6. The operation of switch LGb causes the starting of the car on its downward trip as has been previously explained in the case of car "a". Upon reaching the bottom terminal, car "b" becomes selected as the new active bottom car. Incident to this operation, contacts AB5b-3 separate to break the circuit for the lower coil of switch ITb causing this switch to drop out and thus avoid returning the car to the top terminal.

If in the above example car "d" also failed to take the place of car "a", car "b" is selected as the new middle free car. Upon the separation of contacts XCS1d-3, switch MFd is dropped out so that upon the arrival of car "b" at the bottom terminal, it is immediately selected by the notching device as the new middle free car. Incident to this operation, contacts MF6b-3 separate to break the circuit for the lower coil of switch ITb to cause this switch to drop out and thus avoid returning the car to the top terminal.

Where the failure takes place at the bottom terminal as a result of the doors of the then active bottom car failing to open within the time interval provided for switch XCS for that car, should the doors likewise fail to open on the inactive bottom car, within the time interval provided by the switch XCS for the car, when it becomes the new active bottom car the inactive top car is brought to the bottom terminal to become the new active bottom car as explained above. Should this car, say car "b", fail to come to the bottom terminal, the separation of its contacts XCS3b-3 breaks the circuit for the lower coil of switch ITb, causing this switch to drop out. As a result switch ITC is dropped out and engages contacts ITC1-5 which, inasmuch as contacts ABD1-5 are engaged as there is no active bottom car, connects the coil of switch LJa across resistor RUL1-5. As a result, switch LJa operates to cause the operation of the middle free car "a" to answer the first floor landing call.

Thus it is seen that should the middle free car fail within a certain period to respond to a landing call for a floor above the main landing or to open its doors when parked and a landing button is touched at the parking floor, the active bottom car becomes the new middle free car and answers the call and another car becomes the new active bottom car. Similarly should the doors of the active bottom car when parked fail within a certain period to open when the landing button at that floor is touched, the inactive bottom car becomes the new active bottom car and its doors are opened.

It is, of course, improbable that there will be failure of response of more than one car at a time but it will be taken car of should it ever arise. More likely, one or more cars, i.e., the inactive bottom car or inactive top car or both, will be out of service at the time a failure takes place. Taking cars out of service is effected by opening their OS switches as previously set forth, causing their switches XCS to be dropped out. Thus for example with the inactive bottom car "d" out of service at the time the doors of the active bottom car "c" fail to open, the dropping out of switch ABc at the expiration of the time interval of switch XCSc causes the dropping out of switch ABC and thus switch ABD as there is not a car in service at the bottom terminal to become the new active bottom car. As a result the inactive top car is started immediately to come to the bottom landing to answer the call. Should the inactive top car "b" also be out of service, switch ITC is dropped out so that the dropping out of switch ABD causes the immediate starting of the middle free car "a" to answer the call.

The cars may be operated with attendants by throwing throw-over switches TO for the individual cars into "with attendant" positions "w". As to car "a" for example, the throw over of switch TOa-2 causes the cars to operate as on a "continuous call" basis. The throw over of switch TO2a-4 renders up and down dispatching lights UDLa-4 and DDLa-4 effective to give dispatching signals to the attendants to start the cars, subject to direction contacts UD1a-4 and UD2a-4 and dispatching switch contacts VSD1a-4. The throw over of switch TO1a-7 renders the operation of switch RAa and thus the starting of the car subject to starting button SBa-7 in the car. The throw over of switch TO4a-7 renders the dropping out of switch NTa subject to the dropping out of switch RAa. Thus the starting button also effects the closing of the doors. The throw over of switch TO5a-7 renders resistor R6a-7 ineffective, thus speeding up the door closing operation under with attendant operation. The throw over of switch TO1a-4 causes the lighted hall lantern to be extinguished when the start button is pressed. The throw over of switch TO2a-7 renders the non-stopping of the car subject to the pressing of non-stop button NSBa-7 in the car. The throw over of switch TO6a-7 renders reversal buttons URBa-7 and DRBa-7 effective. Also the throw over of switch TO6a-7 and of switch TO7a-7 renders lowest call reversal circuits ineffective. The throw over of switch TO3a-7 renders switch XCSa subject to the potential switch.

From the above description it will be seen that there is provided a plural elevator system in which the cars may be operated either with or without attendants. On "without attendant" operation the cars may be operated on "on call" operation or "continuous call" operation. The cars are dispatched on their upward and downward trips on both "with attendant" operation and on "without attendant continuous call" operation. The dispatching on "with attendant" operation is effected by giving dispatching signals to the cars whereupon the attendants start the cars. On "without attendant" operation, the dispatching is effected by automatically starting the cars.

On "without attendant" operation the system operates "on call" until service demand conditions dictate the switch over to "continuous call" operation. On "on call" operation, the middle free car parks at a selected middle free car parking floor, the active bottom car parks at the bottom terminal and, in a four car installation, the other two cars park as inactive cars, one at the bottom terminal and one at the top terminal. This provides standby cars for out of service "on call" cars and insures satisfactory distribution of the cars for throw over to continuous call operation. The cars park with the hoistway doors and car doors closed.

Upon the registration of a landing call for a floor above the lower terminal other than the floor at which the middle free car is parked, the middle free car is started in a direction toward that floor and upon arrival thereat is brought to a stop and its doors automatically open. The intending passenger enters the car and presses the car button for his destination. The doors close and the car takes the passenger to his destination where it is brought to a stop and the doors open, permitting the passenger to leave the car. If other calls are registered, the car stops at each floor for which car calls are registered and for which landing calls for the direction in which the car is set to travel are registered. It continues to travel in the same direction after each stop until it stops at the farthest floor in that direction for which a call is registered. This may be a landing call for the opposite direction. When all calls are responded to, the car automatically returns to the middle free car parking floor. If while the car is on its way to the parking floor, a landing call is registered for a floor beyond, the car passes the parking floor and proceeds to the floor of call.

The active bottom car serves incoming traffic. When it is started in the up direction in response to a car call, it assists the middle free car in answering landing calls. If the car does not reach a certain floor, it returns to the bottom terminal as the active bottom car upon answering its highest call, responding to calls on the way down. If on its upward trip it does pass a certain floor, it becomes the new middle free car and the previous middle free car is returned to the bottom terminal. A new active bottom car is selected, usually the inactive bottom car. A changeover is also effected when the middle free car is returned to the bottom terminal. In such event, the active bottom car becomes the new middle free car and goes to the middle free car parking floor and either the previous middle free car or the inactive bottom car becomes the new active bottom car.

Should a car fail to respond within a certain time interval, it is removed from service and another car is caused to take its place. This failure may be manifested in failure to start in response to a call for another floor or failure to open its doors in response to touching a button at the landing where parked. In the case of the middle free car, the active bottom car becomes the new middle free car and the inactive bottom car becomes the new active bottom car. In the case of the active bottom car, the inactive bottom car becomes the new active bottom car. Should in either case the car, which should take the place of the car which failed to respond, fail to do so, another car is caused to take the place of the car which failed to respond.

Should certain service demand conditions arise, the system is automatically switched over to "continuous call" operation. This has been illustrated as occurring upon the registration of one or more than one overlapping landing calls for a certain period of time. Also this time period is shortened in accordance with the number of landing calls in registration. In addition, the changeover is effected in response to the automatic load non-stop operation of a car, provided a landing call is in registration. When the system is thrown over to "continuous call" operation, the cars are selected for dispatching in the order of their arrival at the terminals. The dispatching operations occur at the expiration of given time intervals. When the interval expires, the doors close automatically and the selected car starts on its trip to the opposite terminal.

When on "continuous call" operation, the dispatching interval is adjusted automatically in accordance with whether the cars are early or late on a round trip basis. If traffic increases so as to slow the cars, the interval is gradually increased and, as soon as traffic decreases, the interval is shortened. Also, the dispatching interval may be automatically adjusted in accordance with the number of cars in service.

Under "continuous call" operation, when all landing calls have been responded to for a certain interval of time, the system automatically changes back to "on call" operation. When this occurs, all cars not at the bottom terminal are started to return thereto. A car at the bottom terminal or the first car to arrive there is caused to become the middle free car and go to the middle free car parking floor. When this car leaves the bottom terminal, another car there or the next car to arrive there is selected as the active bottom car and remains at that floor. When the active bottom car is selected, one of the two remaining cars is selected to go to the top terminal as the inactive top car and the other car proceeds to the bottom terminal and becomes the inactive bottom car.

While the invention has been described in connection with an installation of four elevators serving ten floors, it is to be understood that it is applicable for installations of other numbers of elevators and of other numbers of floors. Also, it is applicable to installations not having "with attendant" operation. The invention is applicable to installations having basement service in which case the active bottom car would preferably serve the basement. In addition, late car reversal operation may be provided when operating under dispatching, as for example as disclosed in the patent to Glaser and Hornung No. 2,589,242. It is contemplated that certain features of the invention may be used in connection with apparatus and circuits different from those specifically described and also in connection with other forms of elevator control. This includes the dispatching mechanism which may vary, as for example effecting dispatching at regular time intervals instead of measuring the time from the departure of the cars. Other arrangements for registering calls may be employed. Various alterations may be made, and various operations may be modified.

For example, by throwing over switch CO2-2 to its upper position, switch VUD-2 is operated as indicative of a form of control other than "continuous call" which may be had when service demand changes. By closing changeover switch CO-7 (one for each car), the middle free car, upon responding to a down landing call, is caused to proceed to the bottom terminal. This is effected by switch LYa for car "a", which when a down call is picked up has its operating coil energized by way of contacts XSM2a-7 and PR1a-7. Upon operation, it engages contacts LY1a-7 to become self holding and engages contacts LY1a-5 to cause the bottom terminal circuit to be set up. Upon arriving at the bottom terminal, switch LYa is dropped out by the separation of contacts PR1a-7.

With changeover switches CO1-8 and CO2-8 closed, the system is arranged so that if, under "continuous call" operation, no car starts within a certain interval, say forty seconds, the system is thrown over to an instant start operation. When on continuous call, contacts CC1-8 are separated so that the coil of switch ACT is subject to the H1-8 contacts of the various cars. Should no car start within the time interval after the last to run car stops, switch ACT drops out to separate contacts ACT1-2 and ACT1-3, disconnecting the dispatching circuits, enabling the cars to run wild in response to landing calls. Also contacts ACT2-8 separate in the energizing circuit for the coil of switch ACX. This switch drops out say in five seconds, engaging contacts ACT1-8 to retest the circuit for the coil of switch ACT. When switch ACT drops out it engages contacts ACT3-8 to light signal light IL-8 and sound buzzer BZ-8. These features may be rendered ineffective by opening switch CO1-8 or the test circuit may be rendered ineffective by opening switch CO2-8. Similar operation may be had on "on call" operation and is illustrated as provided by contacts BLX1-8.

As another example of variations that may be made, the control of the operation of switch TT may vary, especially with respect to the conditions which cause its operation and the various time variations employed.

Also, the system may be arranged so that the cars do not have to proceed to the bottom terminal to be selected upon changeover from "continuous call" to "on call" operation.

It is not intended to set forth all the variations that may be made, but it is contemplated that many of the features of the invention disclosed may be carried out in other ways and may be used in connection with apparatus and circuits different from those specifically described and that many apparently widely different embodiments of the invention can be made without departure from the spirit and scope of the invention. It is therefore intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Claims

1. A control system for a plurality of elevator cars serving a plurality of landings including terminal landings comprising; call registering means for each of said landings; means for registering traffic conditions; means responsive to said traffic conditions registering means under intermittent traffic conditions for causing operation of one or more of the cars on an intermittent basis; dispatching mechanism for the cars; and means responsive to said traffic conditions registering means under greater traffic conditions for changing over the operation to cause the cars to be dispatched by the dispatching mechanism from at least one of the terminal landings on a time basis.

2. A control system for a plurality of elevator cars serving a plurality of landings including terminal landings comprising; call registering means for each of said landings; means responsive to actuated call registering means for registering demand for service; means responsive to said service demand registering means under conditions of intermittent service demand registered by said call registering means for causing operation of one or more of the cars on an intermittent basis; mechanism for dispatching said cars on a time basis; and means responsive to said service demand registering means under conditions of greater service demand registered by said call registering means for changing over the operation to cause the cars to be dispatched by said dispatching mechanism from at least one of the terminal landings on a time basis.

3. A control system for a plurality of elevator cars serving a plurality of landings including terminal landings comprising; call registering means for each of said landings; means responsive to actuated call registering means for registering demand for service; means for causing one of said cars to operate as under collective control in response to calls for certain of said landings under certain service demand conditions; and means responsive to said service demand registering means under other service demand conditions of registered calls for causing automatic starting of said cars from at least one of said terminal landings on a time basis.

4. A control system for a plurality of elevator cars serving a plurality of landings including terminal landings comprising; call registering means for each of said landings; means for causing the calls that are registered to be answered by the cars that are in operation; means for causing operation whereby but one of said cars is started in operation in response to the registration of a call; dispatching means for causing operation whereby said cars are automatically started from a terminal landing on a time basis; and call time measuring means subject to said call registering means for determining which of such operations is had.

5. A control system for a plurality of elevator cars serving a plurality of landings including terminal landings comprising; call registering means for each of said landings; means responsive to actuated call registering means for registering demand for service; means responsive to said service demand registering means under conditions of intermittent service demand registered by said call registering means for causing operation of one or more of the cars on an intermittent basis; mechanism for dispatching said cars on a time basis; load weighing means for each car; and means controlled by said load weighing means for a car at the lower terminal landing under conditions where the load taken in that car reaches a certain amount for changing over the operation to cause the cars to be dispatched by said dispatching mechanism from such terminal landing on a time basis.

6. A control system for a plurality of elevator cars serving a plurality of landings including terminal landings comprising; call registering means for each of said landings; means for causing the calls that are registered to be answered by the cars that are in operation; load weighing means for each car responsive to a certain load in the car; automatic load non-stop means for each car responsive to operation of said load weighing means for that car for causing the car to run past landings for which calls are registered; means for causing operation whereby but one of said cars is started in operation in response to the registration of a call; dispatching means for causing operation whereby said cars are automatically started from a terminal landing on a time basis; and means responsive to the operation of said load weighing means for said one car and an actuated call registering means for throwing over the cars to the control of said dispatching means.

7. A control system for a plurality of elevator cars serving a plurality of landings including terminal landings comprising; call registering means for each of said landings; means for causing one of said cars to serve as a free car and park at an intermediate landing; means responsive to the actuation of a call registering means to register a call for a landing other than said intermediate landing and the bottom terminal landing for starting the free car in operation; means for causing said free car to stop at landings above the lower terminal landing in response to actuated call registering means for such landings; means responsive to actuated call registering means for registering demand for service; and means responsive to said service demand registering means under certain service demand conditions of registered calls for discontinuing such free car operation and for causing automatic starting of said cars from said terminal landings on a time basis.

8. A control system for a plurality of elevator cars serving a plurality of landings including terminal landings comprising; call registering means for each of said landings; means for causing one of said cars to serve as a free car and park at an intermediate landing and other cars to park at least one at each of said terminal landings; means responsive to the actuation of a call registering means to register a call for a landing other than the one at which said free car is parked and the bottom terminal landing for starting the free car in operation; means for causing said free car when started in operation to stop at landings above the lower terminal landing in response to actuated call registering means for such landings; dispatching means operable to effect automatic starting of said cars from said terminal landings on a time basis; means responsive to actuated call registering means for registering demand for service; and means responsive to said service demand registering means under conditions of sustained demand for service for a predetermined period of time for throwing over the operation of said cars to the control of said dispatching means.

9. A control system for a plurality of elevator cars serving a plurality of landings including terminal landings comprising; call registering means for each of said landings; means for causing the cars that are in operation to answer registered calls; means for causing one of said cars to serve as a free car and park at an intermediate landing and other cars to park one at the bottom terminal landing as an active bottom car and another at the top terminal as an inactive top car; means responsive when all cars are parked to the actuation of a call registering means to register a call for a landing other than the one at which said free car is parked and the bottom terminal landing for starting the free car in operation; dispatching means operable to effect automatic starting of said cars from each terminal landing upon expiration of a predetermined time interval after the departure from that terminal landing of the next preceding car; means controlled by the time that overlapping calls are registered by actuated call registering means; and means responsive to actuation of said time control means while said free car is responding to calls for throwing over the operation of said cars to the control of said dispatching means.

10. A control system for a plurality of elevator cars serving a plurality of landings comprising; call registering means for each of said landings; means for causing the cars that are in operation to stop in response to actuated call registering means at floors for which calls are registered; dispatching mechanism operable to effect automatic starting of said cars from a terminal one of said landings on a time basis; means responsive to actuated call registering means for registering demand for service; and means responsive to said service demand registering means under certain service demand conditions for causing operation of said cars under the control of said dispatching mechanism and under conditions where the service demand decreases to a certain point changeover of the operation of the system to cause one of the cars to answer subsequent calls as a free car and the other car or cars to park at one or both terminal landings.

11. A control system for a plurality of elevator cars serving a plurality of landings comprising; call registering means for each of said landings; means for causing the cars that are in operation to stop in response to actuated call registering means at floors for which calls are registered; dispatching mechanism operable to effect automatic starting of said cars from a terminal one of said landings on a time basis; means responsive to actuated call registering means for registering demand for service; and means responsive to said service demand registering means under certain service demand conditions for causing operation of said cars under the control of said dispatching mechanism and under conditions where no service demand exists changeover of the operation of the system to cause one of the cars to park at an intermediate landing as a free car, another car to park at the bottom terminal landing as an active bottom car and still another car to park at the top terminal landing as an inactive top car.

12. A control system for a plurality of elevator cars serving a plurality of landings including terminal landings comprising; call registering means for each of said landings; means for causing the cars that are in operation to stop in response to actuated call registering means at floors for which calls are registered; dispatching mechanism operable to effect automatic starting of said cars from a terminal landing on a time basis; means responsive to actuated call registering means for registering demand for service; and means responsive to said service demand registering means under certain service demand conditions for causing operation of said cars under the control of said dispatching mechanism and under conditions where no service demand exists changeover of the operation of the system to cause a car at the bottom terminal landing, or if none is there the first car to arrive, to become a free car and go to an intermediate landing to park, the next car to arrive at the bottom terminal landing to park there as an active bottom car and another car to go to the top terminal landing and park there as an inactive top car.

13. A control system for a plurality of elevator cars serving a plurality of landings including terminal landings comprising; call registering means for each of said landings; means for causing the cars that are in operation to stop in response to actuated call registering means at floors for which calls are registered; dispatching mechanism operable to effect automatic starting of said cars from each terminal landing on a time basis; means responsive to actuated call registering means for registering demand for service; means responsive to said service demand means for causing under conditions where there is a predetermined demand for service existing for a predetermined period of time operation of said cars under the control of said dispatching mechanism and under conditions where said demand decreases to a certain point changeover of the operation of the system to cause the cars to proceed to the bottom terminal landing, a car at the bottom landing, or if none there the first car to arrive, to become a free car and go to an intermediate landing to park, the next car to arrive at the bottom terminal landing to park there as an active bottom car and another car to go to the top terminal landing and park there as an inactive top car; and means responsive when such changeover takes place to an actuated call registering means for a landing other than the one at which said free car is parked, if parked, and the bottom terminal landing for starting the free car in operation to answer calls.

14. A control system for four or more elevator cars serving a plurality of landings including terminal landings comprising; call registering means for each of said landings; means for causing the cars that are in operation to stop in response to actuated call registering means at floors for which calls are registered; dispatching means operable to effect automatic starting of said cars from each terminal landing upon expiration of a predetermined time interval after the departure from that terminal landing of the next preceding car; timed means responsive to said call registering means and operable upon the expiration of a certain time interval after all calls are answered to changeover the operation of the system to cause the cars to proceed to the bottom terminal, a car at the bottom terminal landing, or if none there the first car to arrive, to become a free car and go to an intermediate landing to park, the next car to arrive at the bottom terminal landing to park there as an active bottom car, a car to go to the top terminal landing and park there as an inactive top car and a car to park at the bottom terminal landing as an inactive bottom car; and means responsive when such changeover takes place to the actuation of a call registering means to register a call for a landing other than the one at which said free car is parked, if parked, and the bottom terminal landing for starting the free car in operation.

15. A control system for a plurality of elevator cars serving a plurality of landings comprising; call registering means for each of said landings; means for causing the cars that are in operation to stop in response to actuated call registering means at floors for which calls are registered; dispatching mechanism operable to effect automatic starting of said cars from a terminal one of said landings on a time basis; non-start means responsive to no car starting within a certain time interval after the last to run car stops; and means responsive to operation of said non-start means to changeover the operation to enable the cars to run wild in response to calls until the condition is corrected.

16. A control system for a plurality of elevator cars serving a plurality of landings comprising; call registering means for each of said landings; means for causing the cars that are in operation to stop in response to actuated call registering means at floors for which calls are registered; dispatching mechanism operable to effect automatic starting of said cars from a terminal one of said landings on a time basis; non-start means responsive to no car starting within a certain time interval after the last to run car stops; means responsive to operation of said non-start means to remove the control of the cars from the dispatching mechanism and to cause all of the cars to start in response to calls until the condition is corrected; and means for testing said non-start means upon expiration of a further time interval to determine whether said condition has been corrected.

17. A control system for a plurality of elevator cars serving a plurality of landings comprising; down call registering means for each of said landings above the bottom terminal one of said landings; means for causing one of said cars to serve as a free car and park at an intermediate landing selected as the free car parking floor; means responsive to the actuation of a down call registering means for a landing below said parking floor for starting said free car in the down direction; means for causing said free car when travelling in the down direction to stop in response to actuated down call registering means at landings for which down calls are registered thereby; and means responsive to said free car stopping means upon that car answering the first reached down call on its downward trip under conditions where an additional down call is registered for a landing below for causing the car to continue to travel in the down direction after each subsequent stop until it reaches the bottom terminal landing.

18. A control system for a plurality of elevator cars serving a plurality of landings comprising; down call registering means for each of said landings above the bottom terminal one of said landings; means for causing one of said cars to serve as a free car and park at an intermediate landing selected as the free car parking floor; means responsive to the actuation of a down call registering means for a landing other than the one at which the free car is parked for starting said free car in operation toward the floor for which the call is registered; means for causing said free car when travelling in the down direction to stop in response to actuated down call registering means at landings for which down calls are registered thereby and when travelling in the up direction to stop in response to an actuated down call registering means at the landing for which a down call is registered thereby provided that is the highest call; and means responsive to the initiating of a stop of said free car in either direction in response to a down call for irrevocably causing the car to travel in the down direction after each stop until it reaches the bottom terminal landing.

19. A control system for a plurality of elevator cars serving a plurality of landings including terminal landings comprising; up call registering means for each of the intermediate ones of said landings; down call registering means for each of the intermediate ones of said landings; means for causing one of said cars to serve as a free car and park at an intermediate landing selected as the free car parking floor; means responsive to the actuation of any of said up call registering means or down call registering means for a landing other than said free car parking floor for starting the free car in operation; means for causing said free car when travelling in the up direction to stop in response to actuated up call registering means at landings for which up calls are registered thereby and when travelling in the down direction to stop in response to actuated down call registering means at landings for which down calls are registered thereby; and means responsive, when said free car is the only car responding to calls, to operation of said free car stopping means to initiate the stopping of that car in response to an actuated up call registering means under conditions where no further calls are to be responded to for causing that car to return to said parking floor and to initiate the stopping of that car in response to an actuated down call registering means for causing that car to remain set for downward travel after each stop until that car reaches the bottom terminal landing.

20. A dispatching system for a plurality of elevator cars comprising; means for providing time intervals for dispatching; dispatching mechanism for said cars for dispatching the cars from a given terminal upon the expirations of time intervals provided by said time interval means; means for determining whether the cars are early or late in arriving at said terminal with respect to the expirations of said time intervals; and means responsive only to said early or late car determining means independent of the positions of the other cars for controlling operation of said time interval means to adjust the extent of said interval.

21. A dispatching system for a plurality of elevator cars comprising; means for providing time intervals for dispatching; dispatching mechanism for said cars for dispatching the cars from a given terminal upon the expirations of time intervals provided by said time interval means; means for determining whether the cars are early or late in arriving at said terminal with respect to the expirations of said time intervals; and means responsive only to said early or late car determining means regardless of the positions of the other cars for controlling operation of said time interval means to progressively shorten said interval as successive cars are early in arriving at said terminal and to progressively lengthen said interval as successive cars are late in arriving at said terminal; and timing means for providing leeway to prevent said late or early car determining means in case of a late car from affecting said interval when the lateness does not exceed a certain amount and in case of an early car from affecting said interval when the earliness does not exceed a certain amount.

22. In an elevator system, a structure having a plurality of floors to be served by elevator cars, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure for serving the floors, said system normally controlling the elevator cars to provide a first predetermined service for the floors which is substantially balanced in the directions of travel of the cars, means operable for conditioning the system to control the elevator cars to provide a second predetermined service for the floors wherein preference is given for travel in a predetermined direction, and means responsive to a predetermined demand for service in said predetermined direction from floors of the structure while the system is providing said first predetermined service for operating the conditioning means to condition the system to control the elevator cars to provide the second predetermined service for the floors.

23. In an elevator system, a structure having a plurality of floors to be served by elevator cars, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure for serving the floors, control means for controlling the elevator cars to provide substantially balanced service for the floors in the two directions of travel of the elevator cars, said control means including a dispatcher system operating to dispatch the elevator cars from upper and lower terminal floors at intervals tending to maintain said substantially balanced service, and means responsive to a predetermined demand for service in a predetermined direction from the floors for modifying said control means to provide a preponderance of service in said predetermined direction for said floors by the elevator cars.

24. In an elevator system, a structure having a plurality of floors to be served by elevator cars, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure for serving the floors, first call means for registering calls for service in a first direction of travel from said floors, second call means for registering calls for service in a second direction of travel from said floors, control means for operating said elevator cars for travel in said first and second directions, said control means including stopping means responsive to registration of a call at one of the floors for service for stopping the first available one of the elevator cars to approach the floor at which the call is registered in the direction of travel of the registered call, said control means providing substantially balanced service for said calls registered by the first and second call means, and demand means responsive to a predetermined demand for service from the first call means for modifying the control means to provide a preponderance of service by the elevator cars in said first direction of travel.

25. In an elevator system, a structure having a plurality of floors to be served by elevator cars, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure for serving the floors, first call means for registering calls for service in a first direction of travel from said floors, second call means for registering calls for service in a second direction of travel from said floors, control means for operating said elevator cars for travel in said first and second directions, said control means including stopping means responsive to registration of a call at one of the floors for service for stopping the first available one of the elevator cars to approach the floor at which the call is registered in the direction of travel of the registered call, said control means providing substantially balanced service in the two directions of travel for said calls registered by the first and second call means, selecting means automatically effective during the operation of the elevator system to carry passengers for selecting a first period wherein said substantially balanced service is to be provided and a second period wherein a preponderance of elevator service is to be provided in the first direction of travel, and modifying means automatically responsive to operation of the selecting means to select the second period for modifying the control means to provide a preponderance of elevator service by the elevator cars in said first direction of travel.

26. In an elevator system, a structure having a plurality of floors to be served by elevator cars, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure for serving the floors, first call means for registering calls for service in a first direction of travel from said floors, second call means for registering calls for service in a second direction of travel from said floors, control means for operating said elevator cars for travel in said first and second directions, said control means including stopping means responsive to registration of a call at one of the floors for service for stopping the first available one of the elevator cars to approach the floor at which the call is registered in the direction of travel of the registered call, said control means providing substantially balanced service in the two directions of travel for said calls registered by the first and second call means, selecting means automatically effective during the operation of the elevator system to carry passengers for selecting a first period wherein said substantially balanced service is to be provided and a second period wherein a preponderance of elevator service is to be provided in the first direction of travel, and a third period wherein said substantially balanced service is again to be provided, and modifying means automatically responsive to operation of the selecting means to select the second period for modifying the control means to provide a preponderance of elevator service by the elevator cars in said first direction of travel, said modifying means being responsive to selection by the selecting means of said third period for restoring the control means to provide substantially said balanced service.

27. In an elevator system for carrying passengers, a structure having a lower dispatching floor, a plurality of intermediate floors above the lower dispatching floor, and an upper dispatching floor above the intermediate floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure for serving the floors, motive means for moving the elevator cars relative to the structure, up-call means for registering calls for elevator car service from each of a plurality of the floors of said structure in the up direction, down call means for registering calls for elevator car service from each of a plurality of the floors of said structure in the down direction, control means cooperating with the motive means and the call means in a first operation for stopping each of the elevator cars at each of the floors reached by each of the elevator cars during up travel thereof for which a call is registered by the up-call means and at each of the floors reached by each of the elevator cars during down travel thereof for which a call is registered by the down call means, upper dispatching means for dispatching elevator cars in succession from the upper dispatching floor, lower dispatching means for dispatching elevator cars in succession from the lower dispatching floor, the dispatching means and the control means cooperating to provide a first predetermined balanced service in the two directions of travel for said calls registered by the first call means and the second call means, said elevator cars during said balanced service being dispatched successively substantially at intervals from the lower dispatching floors for upward movement and said elevator cars during said balanced service being dispatched successively substantially at intervals from the upper dispatching floor for downward movement, selecting means automatically effective during the operation of the elevator system for selecting a first period wherein said substantially balanced service is to be provided and a second period wherein substantially greater passenger-carrying service is to be provided by the elevator cars in a selected one of said directions than in the other of said directions, and modifying means responsive to operation of the selecting means to select the second period for modifying the control means to provide a substantially greater passenger-carrying service in said selected one of said directions than in the other of said directions.

28. In an elevator system for carrying passengers, a structure having a lower dispatching floor, a plurality of intermediate floors above the lower dispatching floor, and an upper dispatching floor about the intermediate floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure for serving the floors, motive means for moving the elevator cars relative to the structure, up-call means for registering calls for elevator car service from each of a plurality of floors of said structure in the up direction, down call means for registering calls for elevator car service from each of a plurality of the floors of said structure in the down direction, control means cooperating with the motive means and the call means in a first operation for stopping each of the elevator cars at each of the floors reached by each of the elevator cars during up travel thereof for which a call is registered by the up-call means and at each of the floors reached by each of the elevator cars during down travel thereof for which a call is registered by the down call means, upper dispatching means for dispatching elevator cars in succession from the upper dispatching floor, lower dispatching means for dispatching elevator cars in succession from the lower dispatching floor, the dispatching means and the control means cooperating to provide a first predetermined balanced service in the two directions of travel for said calls registered by the first call means and the second call means, said elevator cars during said balanced service being dispatched successively substantially at intervals from the lower dispatching floors for upward movement and said elevator cars during said balanced service being dispatched successively substantially at intervals from the upper dispatching floor for downward movement, selecting means automatically effective during the operation of the elevator system for selecting a first period wherein said substantially balanced service is to be provided and a second period wherein substantially greater passenger-carrying service is to be provided by the elevator cars in a selected one of said directions than in the other of said directions, and a third period wherein the balanced service is again to be provided, and modifying means responsive to operation of the selecting means to select the second period for modifying the control means to provide a substantially greater passenger-carrying service in said selected one of said directions than in the other of said directions, at least one of the elevator cars during said last-named service being conditioned when set for up travel to reverse substantially at the highest floor for which a call is registered by the down-call means provided that no call is registered by the up-call means for such highest floor and provided that no call for a floor above such highest floor is registered by the up-call means, said modifying means being responsive to selection by the selecting means of said third period for restoring the control means to provide substantially said balanced service.

29. In an elevator system for a structure having a plurality of floors including a first terminal floor, a second terminal floor, and a plurality of intermediate floors located between the terminal floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve said floors, separate motive means for moving each of the elevator cars relative to the structures, and control means for controlling the movement of the elevator cars by the motive means and the stopping of the elevator cars at predetermined floors, said control means including call-registering means operable for registering calls for elevator service, dispatching means cooperating with the control means for successively selecting and starting elevator cars to be dispatched from each of said terminal floors, and transfer means cooperating with the control means in response to absence of a call registered by said call registering means for parking said elevator cars, said transfer means being responsive to the presence of call registration by the call-registering means for cooperating with the control means to start successively, a plurality of the parked elevator cars and to place the started elevator cars under the control of the dispatching means.

30. In a plural car elevator system for a structure having a plurality of floors including a first terminal floor, a second terminal floor, and a plurality of intermediate floors located between the terminal floors, motive means for moving each of the elevator cars relative to the structure, and control means for controlling the movement of the elevator cars by the motive means and the stopping of the elevator cars at predetermined floors, said control means comprising call registering means operable for registering a call for each of a plurality of the floors, dispatching means for dispatching available elevator cars from the first terminal floor at intervals, means effective in the absence of calls registered by the call registering means for parking said elevator cars at parking stations, means responsive to call registration by the call-registering means for dispatching a first one of the elevator cars from its parking station and starting measurement of an interval of time, and means responsive to a predetermined call registration at the end of the last-named interval for initiating movement of a second one of the elevator cars from its parking station.

31. In an elevator system for a structure having a plurality of floors including a first terminal floor, a second terminal floor, and a plurality of intermediate floors located between the terminal floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve said floors, separate motive means for moving each of the elevator cars relative to the structure, and control means for controlling the movement of the elevator cars by the motive means and the stopping of the elevator cars at predetermined floors, said control means comprising call-registering means operable for registering a call for each of a plurality of the floors served by the elevator car, dispatching means effective when energized for successively selecting elevator cars to be dispatched from one of the floors, and energizing means responsive to the presence of a predetermined call registration by the call-registering means for energizing the dispatching means.

32. In an elevator system for a structure having a plurality of floors including a first terminal floor, a second terminal floor, and a plurality of intermediate floors located between the terminal floors, a plurality of elevator cars, means mounting the elevator cars for movement relative to the structure to serve said floors, separate motive means for moving each of the elevator cars relative to the structure, and control means for controlling the movement of the elevator cars by the motive means and the stopping of the elevator cars at predetermined floors, said control means comprising first call-registering means operable for registering a call from each of a plurality of said floors from which elevator service in a first direction towards the second terminal floor is desired, second call-registering means operable for registering a call from each of a plurality of floors from which elevator service in a second direction towards the first terminal floor is desired, dispatching means effective when energized for successively selecting elevator cars to be dispatched from one of the floors, and means responsive to the call registration by any of said call registering means for energizing the dispatching means.

33. In an elevator control system, in combination, a plurality of cars arranged to serve a plurality of floors, means for registering calls for service, means for each car for stopping the car at floors at which calls are registered, a sensing circuit comprising unilateral conducting devices corresponding to the path of the cars, a source of power having a first and a return lead, means for energizing the sensing circuit from the first lead at points corresponding to registered calls, said sensing circuit in response thereto conducting current in two directions for calls registered at floors intermediate the terminal floors, said two directions corresponding to both directions in which a car can travel from said intermediate floors, current responsive means connected to the sensing circuit and to the return lead arranged to shunt current from said circuit at points corresponding to the car positions, and car starting means actuated by said current responsive, means for starting said car in response to current shunted from said circuit.

34. In an elevator control system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for registering calls for service, means for each car for stopping the car at floors at which calls are registered, a sensing circuit comprising unilateral conducting devices corresponding to the path of the elevator cars, energizing means having a first lead and a return lead, current limiting impedances connecting the first lead to the sensing circuit at points corresponding to registered calls, current responsive means for each car connecting the return lead to the sensing circuit at points corresponding to car positions, car starting means actuated by said current responsive means, and means for reversing the direction of travel of a car when the only current flowing in its current responsive means indicates a call requiring travel in the opposite direction.

35. In an elevator control system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for moving the cars from floor to floor, means for registering calls for service, means for each car for stopping the car at floors at which calls are registered, a sensing circuit comprising unilateral conducting devices corresponding to the path of the elevator cars, current supply means having a first and a return lead, means including current limiting impedances connecting the first lead to the sensing circuit at points corresponding to registered calls, current responsive means connecting the return lead to the sensing circuit at points corresponding to the position of each car, car starting means connected to the current responsive means, said current responsive means including a portion responsive to current flow indicating more than a predetermined number of calls, and means cooperating with said portion arranged to momentarily interrupt the circuit through said portion whereby current flows through the current responsive means to start a next car.

36. In an elevator control system, in combination, a plurality of elevator cars arranged to serve a plurality of floors, means for moving the cars from floor to floor, means for registering calls for service, means for each car for stopping the car at floors at which calls are registered, a sensing circuit comprising unilateral conducting devices and corresponding to the path of the elevator cars, a current supply means having a first lead and a return lead, means including current limiting impedances for connecting the first lead to the sensing circuit at points corresponding to registered calls, current responsive means for each car connecting the return lead to the sensing circuit at points corresponding to the position of the car, relay means responsive to the presence of at least two cars at a lobby floor, said relay means preparing circuits for starting all but one of said cars at the lobby, and means for stopping said started car at an intermediate floor until a signal is registered requiring travel by such car.

37. An elevator control system according to claim 36 in which cars started from the lobby by the arrival of other cars travel to and stop at different floors in anticipation of hall calls from the various floors. 38. In an elevator system, in combination, at least three elevator cars arranged to serve a plurality of floors including a lobby floor, a terminal floor and a plurality of floors intermediate said lobby and terminal floors; means for moving each car from floor to floor; a control for each car setting its travel direction; means for automatically starting each car having its control set for travel toward the lobby floor; lobby means for automatically starting a car standing at the lobby floor in response to the arrival of another car at the lobby floor; means for stopping a car started by said automatically starting lobby means at a floor at which no other car is stopped; means for each of said floors for registering hall calls for service by said cars at said floor; hall call transmitting means responsive to calls registered by said call registering means for certain floors for transmitting each said certain call to that car of said plurality of cars located at the floor most proximate said floor of said certain call; and means for starting only said most proximate car towards the floor of said certain call in response to said call transmission by said transmitter means.

39. A combination according to claim 38 wherein said car stopping means includes means for predetermining a plurality of parking floors each spaced from other parking floors by at least one floor which is not a parking floor.

40. An elevator system comprising at least three elevator cars serving a plurality of floors including a main floor, means for each of a plurality of said floors for registering a call for service at said floor; means for assigning registered calls to individual cars; means for moving each of said cars to said floors in response to calls for service for said floor assigned by said assigning means to said cars; means for maintaining a first car at a floor of said plurality of floors other than said main floor when all calls imposed on said system are assigned by said assigning means to other than said first car; means for maintaining a second car at a floor of said plurality of floors other than said main floor when all calls imposed on said system are assigned by said assigning means to other than said second car; means for each car for sensing passenger activity in said car; detecting means for each car each having a first condition when its respective car is at said main floor, each said detecting means having a second condition when its respective car is spaced from said main floor, and actuating means operating in response to all but one of said detecting means being in said second condition and to the sensing by said sensing means of passenger activity in said car whose detecting means is in said first condition for causing one of said first and second cars to run to said main floor.

41. An elevator system according to claim 40 including means for each car for registering car calls for service to each of a plurality of landings for passengers within said car; said sensing means being responsive to registration of a car call on said car call registering means for said car.

42. In an elevator control system, in combination, a plurality of cars arranged to serve a plurality of floors, means for registering calls for service, stopping control means for each car for stopping the car at floors at which calls are registered, a sensing circuit comprising a series chain of unilateral conducting devices corresponding to the path of the elevator cars, means supplying current to the junctions between the conducting devices, said junctions corresponding to floors having registered calls, direct current responsive means individual to each car and connected to the series chain at a position corresponding to the car position and direction of travel, each said stopping control means stopping its respective car for calls upon encountering the floors associated with said calls when current flows through said sensing circuit in one direction only, and means preventing a car's stopping control means from stopping its respective car for certain calls under conditions where current flows through a portion of said sensing circuit in a second direction opposite said first direction as well.

43. An elevator system comprising at least three elevator cars serving a plurality of floors distributed along the paths of travel of said cars, means for each of a plurality of floors for assigning registered calls to individual cars, means conditioning each car as an idle car in response to the absence of a call for service assigned to said car, means to maintain each of a plurality of said cars conditioned as idle cars by said conditioning means at floors other than a main floor, means to start a first idle car in response to a call for service assigned to said car, and means to start a second idle car in response to a predetermined call registration of calls assigned to said first idle car.