US2507791A - Vertical lift control system - Google Patents

Description

May 16, 1950 LE ROY H. KIESLING VERTICAL LIFT CONTROL SYSTEM Filed Oct. 6, 1949 II T GAR"

I 'WHHHI HIH -6 Sheets-Sheet 1 INVENTOR LEROY H. KIESLING ATTORNEY May 16, 1950 Filed Oct. 6, 1949 LE ROY H. KIESLING VERTICAL LIFT CONTROL SYSTEM 6 Sheets-Sheet 2 E ROY H. KlESLlN ATTO R N EY y 1950 LE ROY H. KEESLING VERTICAL LIFT CONTROL SYSTEM 6 Sheets eet 3 INVENTOR LEROY H. KIESMNG Filed Oct. 6 949 WWW-7 y 1950 LE ROY H. KIESLING 2,507,791

VERTICAL LIFT CONTROL SYSTEM Filed 061;. 6, 1949 6 Sheets-Sheet 4 !NVENTOR LEROY H KIESLING ATTORNEY,

May 16, 1950 LE ROY H. KIESLING 2,507,791

VERTICAL LIFT CONTROL SYSTEM Filed Oct. 6, 1949 6 Sheets-Sheet 5 i fi Moro/e L CIRCUITS WVENTOR LEROY H. KIESLING May 16, 1950 LE ROY H. KIESLING 2,507,791

VERTICAL LIFT CONTROL SYSTEM Filed Oct 6, 1949 6 sheets'sheet 6 INVENTOR LEROY H. K ESLING ATTO RN E! Patented May 16, 1950 UNITED STATES PATENT OFFICE 31 Claims.

The present invention relates to vertical lift systems of the type wherein a car operating in a vertical hatchway is raised or lowered from one floor or level to another. It is particularly concerned with the provision of improved control systems for such vertical lift systems for enabling them to be employed primarily as elevators or dumbwaiters, and for greatly improving their usefulness.

The present application is a continuation-inpart of my application Serial No. 31,672 filed June 8, 1948, now abandoned.

Heretofore, dumbwaiters of the motor-propelled type have lacked features of memory circuits for delayed response to calls signalled before readiness of the system to perform the ordered function. Accordingly, an attendant at one station of such a system would spend a great amount of time at the dumbwaiter station, persistently pressing a call button, until the eventual response of the system, and much time which otherwise could have been used for productive effort was consumed in this way.

In my U. S. patent application Serial No. 794,955 filed December 31, 1947, now Patent No. 2,493,293 of January 30, 1950, I have set forth a control system for two-station dumbwaiters wherein sending circuits and memory features are provided, such that an operator may load the dumbwaiter car at one of the stations and depress two buttons, and then close the dumbwaiter doors with the assurance that the dumbwaiter car will proceed to the other station, wait there for an operator to unload it, and thereafter return to him automaticall when the operator at the other station has completed his task of unloading and/ or loading the car.

Similarly, in my system of application Serial No. 794,955, an operator at one station may signal a call to bring the car to him from the other station, with the assurance that this signalled call will be honored. If the dumbwaiter system is in readiness for immediate response to the call at the time it is signalled, the car will proceed at once to come to the station from which the operator has signalled. If the dumbwaiter system is not in readiness for immediate response to the an, then a holding circuit condition is set up which will survive all intervening functions which may occur in the system, so that upon full preparation of the system to permit the car to come to the station at which the signal was given, it will proceed automatically to do so.

It is an important object of the present invention to provide a vertical lift system serving not only two terminal stations but also one or more intermediate stations, and embodying the operational features described above for the two-station system of application Serial No. 791,955, as well as further features to be set forth below.

It is a further important object of the present invention to provide a vertical lift system serving two terminal stations and at least one intermediate station, and s0 arranged that call signals can be registered at any one or more of the stations and will be stored in memory circuits and given ultimate effect in the turn dependent upon the direction of movement of the car and the order in which the calling stations are reached in such direction of movement. According to this object of the invention, if the car were moving toward the fourth station of a system to answer a call signalled from that station, and during its movement between the first and second stations, call signals were placed for the first, second and third stations, whatever the order of signalling of these three calls the car would stop at the second station, then at the third station, then at the fourth station, and then would proceed non-stop to the first station. If a still further call were re istered at one of the intermediate stations after the car had proceeded upward beyond such station and before it had returned on its mission to the first station, the car would again be compelled to stop at the intermediate station, as the further call signalled therefrom would also take precedence over the first-station call, being earlier reached by the descending car.

Yet another object of the present invention is the provision of a vertical lift system serving two terminal stations and at least one intermediate station, the control system for this vertical lift system being so arranged that the car can be made to travel non-stop from an initial station to a selected destination regardless of an interveningstation calls previously or subsequently placed, and regardless of the direction of movement prior to arrival at said initial station, such express or priority movement of the car being accomplished at the will of a sending operator, i. e. an operator having the car at his disposal at the initial station. This feature is needed in order to insure the most efiicient use of a multi-station dumbwaiter system, in that an operator loading the car at an initial station for a known destination is permitted to prevent any interruption of the car movement until it has reached that destination and been unloaded there.

If an operator at the first floor of a four-story building has material to be moved to the third door, for example, and that material amounts to three loadings for the car, the first floor operator can load the car and send it to the third floor, so that it proceeds to that floor regardless of any calls which may be stored in the system or may be placed in the interval of movement. Likewise, an operator at the third floor may unload the car and/ or load it with material for the first floor, and ma send it directly back to the first door, and this routine can be repeated until the entire stock has been moved. If this feature were not provided, the car with its load of material for the predetermined destination could be caused to make time-consuming and entirely unproductive trips and/or stops at intervening stations, and thus the efliciency of the system for dumbwaiter purposes would be materially impaired.

Still a further object of the invention is to provide a control system for a lift system having a car arranged to serve two terminal stations and at least one intermediate station, and so arranged that th movement of the car can be controlled through the manual operation of con trol switches located within the car, and ar ranged in such a way that the express priority movements as described above can be achieved through the operation of selected express buttons in the car, the arrangement being such that calls may nevertheless be placed at any one or more of the stations served by the system, and these will be stored until the car can come to these call stations in its direction of movement and free from priority requirements inserted through sending signals.

In fulfilling this last-stated objective, a control system is achieved which is suited not only for dumbwaiter purposes but for certain freight and passenger elevator requirements as well, the express control button switches in the car being available to one operating them on the car when it is fully loaded for a remote station so that he can postpone the stops of the car at the calling stations until the tlip has been completed and the car load has been reduced to such an extent that the car can serve a useful purpose in stopping at the calling stations.

Yet a further object or" the present invention is to provide a vertical lift system for upper and lower terminal stations and least one intermediate station, the system being arranged in such a way as normally to have calls at a plurality of stations answered in the turn corresponding to their order as reached in the direction oi travel in :ich the car is in progress, but with special emergency call rr'ans for bringing the car to a station immediately not th standing other calls for the the other cails being held stored nonetheless un il they are answered.

The foregoing objects and features or" the invention will be enlarged upon, and further jects and features will become apparent in the detailed description which follows, taken with reference to the drawings, wherein:

Figs. 1 and 2 are a schematic hatchway diagram and a circuit diagram. respectively, of a three station embodiment of the invention having fixedly located switches call s itches, only;

T 3 and are hatchway cir grains, respectively, or a four-station ems oi" the invention including emergency call switches and a s of car switches; and

5 is illustration of a retiring-cam fea- 4 ture modification applicable to either of the loregoing systems.

Fig. 1 shows the general scheme of a threestation dumb-waiter hatchway, the car l being illustrated as between stations II and Ill. An access door is provided at each station, verticalsliding access door 8 at station I being illustrative, and the other doors being omitted for simplilying the drawing. Each access door is pro vided with a switch, e. g. switch 59, arranged to be held closed when the access door is entirely closed, and to be open at all other times. Well known mechanism may be provided to retain the doors locked closed except when the car pres ent, but such mechanism, not being part of the present invention, is not shown in the drawing.

Three cam-operated switches are provided at each terminal station, i. e. stations I and III, and two-cam-operated switches are provided at the intermediate station II. Switches i5, 25 and 35 are normally open switches for the car-sending switch circuits. Switches 5? and 3'! are normally closed lower and upper limit switches for arresting the car at the respective terminal stations. Switches Hi and 33 are supplementary normally open switches at the terminal stations, and switch 26 is an intermediate-station doublethrow switch. To simplify the drawing, two cams 5 and B are shown on opposite sides of the car l, but in practice a single cam Or a set of cams may be provided at one side or the rear of the car, if preferred.

In Fig. 2, a set of manual control or order switches is provided at each station, each set in cluding one button switch for each floor or station served by the dumbwaiter system. Each of these switches is designated by a two-digit number, the first digit representing the station at which the switch is located, and the second digit representing the station to which that switch is to direct the car. E. g., switch i2 is a switch at the lowermost station I for sending the car to station II, and switch 33 is a switch at the third station for calling the car to that station.

Two main relays 5G and 88 are provided for controlling the dumbwaiter car propulsion circuits, a normally open contactor 5? on relay 5% being connected to the motor coils for permitting the descent of the car, and a normally open contactor' (ii on relay 66 being connected to the motor coils for operating the motor in the direction to raise the car. The motor and the connections therefor are omitted, these connection arrangements being well known in the art.

A quick-opening, delayed-reclosing relay 10 with a normally closed contactor l! is provided for retention of the car at a station for a reasonable time after arrival. This relay is connected to the coil circuits of relays 50 and 6G for blocking their operation during the predetermined interval after arrival of the car at a station.

Direction-control relays 88 and 99 are connected to relays 50 and 60, respectively, and arranged to be energized to block the operation of the respective main relays. These relays have normally closed contactors 8! and 9|, each connected by cross-connections in the coil circuit of the opposite relay. Further normally closed contactors 82 and 92 are connected in series with. the coil circuits of the respective main relays. Normally open contactors 83 and 93 on these relays are arranged in holding circuits.

Contactors 8i and 9| of these relays are arranged to prevent both relays from being energized simultaneously, energization of either 01' these relays resulting in the blocking of the energization circuit of the other. By virtue of the connection of contactors 82 and 92 in series with the coils of relays 50 and 60, energization of relay 80 blocks the coil circuit of relay 50, and energization of relay 90 blocks relay B0.

A pair of triple-contactor relays E00 and i R0 are provided with their coils connected to the contactors 2'! and 28, respectively, of the doublethrow intermediate station switch 25. lays serve with the switch 26 to provide the effect of a triple-pole, double-throw switch. All contactors of these relays are normally open. The double-throw switch 26 is arranged as shown in Fig. 1 in such a way that contactor 21 is closed when the car is above, and contactor is closed when the car is below station II. Furthermore, when the car descends to station II it switches over the mechanism to open contactor El and close contactor 28 and when it ascends to station II, it switches over the mechanism to open contactor 20 and close contactor 21. With relays I00 and H0 connected as shown in Fig. 2, contactors I01, I02 and I03 are closed when contactor 2'! is closed; and contactors HI, H2 and H3 are closed when contactor 28 is closed.

Relays I20 and 130 are provided for holding circuits for bringing the car to the intermediate station II, relay I20 being actuatable for a descent of the car from station III, and relay I being actuatable for an ascent of the car from station I. Supplementary relays I and 550 are provided in connection with relays I20 and I30, for reasons which will subsequently be made evident.

A relay IE0 is provided for holding a circuit for causing ascent of the car to the upper terminal station III, and a relay H0 is provided for causing descent of the car to the lower terminal station I. A pair of priority-order relays I80 and E00 are provided for super-control of the car movements according to those car sending orders requiring the car to proceed from a terminal station past the adjacent station (in the case of a threestation system, past the intermediate station II) to a remote station, and according to all send orders placed at the intermediate station II.

Relay I80 is connected with switches l3 and 23, and with relay I60, to cooperate with the latter relay in response to a signal placed through either of these switches and to temporarily forestall any other operation of the car than that signalled through one of these switches. Relay I90 simi larly is connected with switches 2i and 3|, and with relay I10, to cooperate with the latter relay in response to a signal placed through either of these switches and to forestall temporarily any other operation of the car until such a priority order has been fully carried out.

The operation of the dumbwaiter system of Figs. 1 and 2 may best be described by considering a few examples of orders or demands which may be made through the station order button switches, and the operation which ensues. For a first example, assume that the car is positioned at the first floor station, 1. e. station I, and that the operator there loads the car with material to be moved to station II; and further assume that this operator at station I wishes to recall the car immediately after the delivery to station II, as for sending further material to station II or another station. Upon completion of the loading of the car for station II, the operator closes the car gate (omitted from Fig. 1 for simplicity), with the result that the cargo is protected and the gate contactor switch 9 is closed. If the operator closed These rethe access door 8 also, immediately he would render the car subject to immediate response to a call of the car to another station.

Before closing the sliding door 8, and thus while in full command of it, the operator momentarily depresses buttons 12 and l I, the former for sending the car to station II, and the latter for recalling it. The order of depressions of these switches is inconsequential, the present system being made to take into account the likelihood of careless operation and to safeguard against improper operation due to failure to observe special order procedures. By way of illustration of the tolerance of the system for operator carelessness, suppose the operator signals the recall order by depression of button H first, and then presses button l2.

The car being at the lower station I, cam 5 holds switch it closed, and cam 6 holds switch it closed and switch i? open. Through switch it, a circuit is established from the positive supply conductor through conductor 2%, through normally closed contactor 9i, and through the coil of relay 20 to the negative supply conductor. Relay 80 is therefore energized so long as the car remains at station I, blocking any energization of relay 50 and hence any downward motivation of the car. Moreover, the car being below station II, switch 20 is in the throw condition with contactor 2l open and conductor 28 closed, and the contactors HI, H2 and N3 of relay 5 it are accordingly closed.

The depression of button H provides current flow from the positive conductor, through conductors 205 and 2%, through contactor 83 and conductor 20?, and through the coil of relay 570 to the negative conductor, so that relay H0 is actuated. lhe consequent closure of contactor H3 establishes a holding circuit from the positive conductor, so that this circuit condition is maintained after the release of button I l.

The circuit established for bringing the upper end of the coil of relay H0 to the potential of the positive supply conductor is also effective to place conductor 200 at the positive supply voltage, and so long as relay I80 remains inactive and contactor I86 remains closed, c0nductor 2i i is given the same voltage. Through contact-ors ill and H2 which now are held closed, conductors 2E3 and 2E5 also are held at positive potential. Current flow through conductor 215 is blocked by open contactor ti, but current is carried through conductors 213 and 2H, contactor l2! and conductor 2 i 0 to the coil of relay I40, and through this coil to the negative supply conductor. Relay M0 is therefore actuated, and the positive supply potential is then extended through conductor 22! and contactor MI, and through conductor 223 and contactor I 22, to conductors 225 and 227, current flow through the latter being blocked by the open contactor 82 0f energized relay 80.

Now, upon the closing of car-sending button 2, a circuit is established from the positive conductor through conductor 229 and conductor 23 I, through closed contactor H2 and conductor 233, to the coil of relay 530, which is therefore energized. A. holding circuit for relay I30 is now established through contactor HI and conductor 235 and contactor E35, so that relay I30 is retained in actuated condition after the depression of switch l2.

A circuit for the energization of relay B0 is now completed through relay 30. This circuit may be traced over either of two routes from the positive su ply conductor to contactor I33, one

route being through contactor I81, conductor 23?, contactor lQT, conductor 239, conductor 24], contactor I I3 and, conductor 240; and the second of the two routes being through switch I6, conductor 203, conductor 245, and contactor I34. Through contactor i3: and conductor 24! and contactor 92 the positive-potential supply circuit is completed to the upper terminal of the coil of relay 56, so that this relay is energized and the motor commences lifting the car toward station II.

As the car rises upward, cam 6 first clears switch I! and later clears switch I6. No circuit being dependent upon switch Il' so long as relay lll'is energized. and contactor 83 is closed, the closing of this switch is without any immediate effect. The ensuing opening of switch I6 prevents the supply of current through conductor 2G3 to the coil of relay 80, but the current path through contactors I81 and I91, conductors 2353 and 24!, contactor H3, conductor 243 and contaotor i3 5 remains intact and keeps relay 8!! energized.

As the car reaches station II, cam 6 engages the double-throw switch 26 and opens contactor 28, at the same time causing the closing of contactor 2?. Relay III] is thus deenergized and relay IE is energized. The openin of contactor I! l interrupts the holding circuit of relay I35, so that this relay also is deenergized. The supply of current through contactor I33 and conductor 241 is thus broken, so that the energization of relay GI! ceases and the car is stopped at station II.

At the same time that the opening of contactor 33 breaks the circuit through the coil of relay 59, contactor I34 opens and breaks the supply of current through conductor 245 and contactor SI to the coil of relay 80. This relay is therefore deenergized just simultaneously with relay 69.

In accordance with the principles set forth in my copending U. S. patent application Serial No. 794,955, filed December 31, 1947, the quick-opening, delayed-reclosing relay 1G is interconnected with relays E! and 66 in such a way that the actuation of either of these motor control relays results in the immediately subsequent actuation of relay It, so that contactor H is opened. The opening of contactor 71 is prevented from having any immediate effect upon the actuation circuit of the then effective motor control relay, by the arrangement of normally open contactors 53 and to insure that contactor H be shunted from the time immediately before the opening of contactor 'II to the end of the period of actuation of the effective motor control relay. Then, however, with the opening of the actuation current through the coil of the eiiective motor control relay, both of contactors 53 and 63 are open, so that contactor ll, being held open for a predetermined period of time by the action of delay mechanism 72, positively blocks the energization of a motor control relay during this period and thus compels the car to wait at the station at which it has arrived before responding to any further signal, whether new or stored from a previous button depression.

The deenergization of relay 8i? simultaneously with that of relay does not break the holding ci suit of relay i'ifi, because upon the commencement of upward movement of the car, lower limit switch i1 reclosed and held complete current path from the positive supply conductor through contactor H3 and conductor Immediately following thedeenergization of relay 80, however,

and as a consequence thereof, the closing of contactor 8| completes the energization circuit for relay as traceable from the positive supply conductor through contactor I13, conductor 249, switch it, conductor 2:39, contactor I86, conductor 2! I, contactor H2 and conductor 2H3. At the same time, the closure of contactor 82 brings the upper end of the coil of relay 5! to the positive supply potential, the circuit being traceable from the positive supply conductor through contactor I73, conductor 2 3. switch 2, conductor 269', contactor i86, conductor 2! I, contactor I'H, conductors 253 and 2H, contactors Il and I22, conductor 22?, and contactor 82 to the coil of relay As the restoration of contactor 82 to its closed resting position cannot occur instantaneously upon the cessation of current through the coil of relay 8-9, but necessarily results a moment later, and since a still further moment is required for the response of relay after closure of contaotor 82, contactor cannot be closed before contactor has opened, so that the continuity" of the circuit shunting contactor TI is momentarily broken, satisfying the requirements for relay iii to insure the delay before the car can again be started on its way.

Now, when the predetermined delay interval has'elapsed after cessation of the current through the coil of relay 553, mechanism 52 allows the contactor l! to resume its normally closed condition. Upon this reclosure, assuming that the series-connected gate and door switches 9, I9, 2?; and 39 are then closed, the curent path through the coil oi relay 52 and on to th negative supply conductor is completed, so that relay 59 starts the car on its downward travel in obedience to the station I recall order being held by relay I70.

[is the car starts downward, it again switches over the arms of switch causing the opening of relay ice and the closing of relay Hi This closing of relay Hil, of itself, is unable to establish any complete circuits, as will be seen by tracing the connections to each of its contactors HI, H2 and H3. However, it does render the up direction holding circuits receptive to any updirection call signal which may be given through button 22.

Relay 5c remains energized and the car accordingly is driven downward until earn 6 engages switch it, opening this switch and interrupting the energization of relay I'EG, relay relay M9, and relay and therefore arresting the descent of the car at the position of the access door at station I.

Car cam 5 having engaged and closed switch 56 just prior to the stopping of the car, and relay having been deenergized immediately thereafter by the opening of switch II, with c0nseuent reciosure of contactor the circuit from the positive supply conductor through switch It, conductor and contactor being thus completed, energizes relay assuring readiness of the car system to respond to an Lip-direction order, only.

Throughout the foregoing description of an example of the operation of the dumbwaiter sys tem of the present invention, it has been assumed that no conflicting calls were signalled into the syster.-. It will be readily apparent, however, that the system must be receptive to a call signal at any time, and that a call signal may be inconsistent with other signals to which the car must respond. A fundamental feature of the present arrangement is that it possesses memory characteristics for all calls which may be placed, and that in the absence of send orders, the car will be made to respond to these orders in the turn determined by its location and direction of travel. A send order, on the other hand, is given priority over all call orders.

The send order by which the car was sent to station II in the foregoing illustration insured that the car would go directly to station II and stop there, as this was the first station in the only possible direction of travel of the car from station I. If a call order has been signalled from station III at the same time that the send order was signalled at station I for sending the car to station II, the system would require no special priority arrangements for the response to the send order first, since in this instance the send order to station II is an order calling for movement of the car to the next station in its required direction of travel (and only possible direction from station I).

To illustrate a condition requiring a special priority circuit operation, take an example with the car located at station I, and suppose the operator at station I depresses switch button l3, signalling an order for sending the car to the third station.

Now, in view of the fact that a call order could be signalled at station II before this station III send order is placed, or at the same time as the send order, or thereafter but before the car has passed beyond station II on route to station III in response to the send order, the present invention includes arrangements for insuring that the car will proceed directly to station III notwithstanding the call ahead, so that the send order is given full priority. This send order priority is accomplished by the operation of the station III destination priority relay I80, along with the holdingrelay 16!! which would be actuated in any case for bringing the car to station III. Note that a station III call order, placed through switch 33, would actuate merely relay Ifill, having no effect on relay I80, and such a call order would not take precedence over a station II call.

While the car is at station I, cam holds switch I5 closed, so that a send order can be placed at this station. The depression of switch I3 completes the circuit for actuation of relay I80, through conductors 253, 255, 25? and 259, contactor I94, and conductor 28!. Relay IGEI is thereupon energized through contactor I8l, conductor 25-3, upper limit switch 3'! and conductor 265, and once energized, relay I60 remains energized through the holding circuit provided by contactor Itl in series with limit switch 37.

The down-direction blocking relay 80, initially energized through switch I6, conductor 2533 and contactor 9! while the car is at station I, is retained energized through conductor 2E1, contactor I85, conductor 269, contactor I63 and conductor 2H for so long as upper limit switch 3'! remains closed, and hence until the car reaches its destination, station III.

Relay I89 having been energized and having caused the actuation in turn of relay 250, a holding circuit is established for retaining relay ISIE energized, this circuit being traced through contactor ISI, limit switch 31, conductors 265 and 267, contactor I96, conductor 269, contactor I32, conductor 27S and contactor I82.

So long as the car is below station II, contactor 28 is closed and relay I I0 is energized.

Through energized relay I80, a circuit is established for the energization Of relay 6d, and therefore the motor operates to lift the dumbwaiter car toward station III. The circuit through which the coil of relay 6!] is supplied is traced through contactor I83, conductor 215, conductor 241 and contactor 92.

From the foregoing explanation, it will be apparent that the depression of the station III send button I3 energized relay ISII, and through this relay, further relays Ilil, 86 and Iii were energized. Through energized relay I65, two holding circuits were establishedone through contactor I 6! to hold relay IE6 energized so long as the upper limit switch 3'! remains closed, and one through contactor I 62 and conductor 2'53 holding relay I88 energized so long as the upper limit switch remains closed. It will be apparent, further that the interconnections among these four energized relays are independent of switch 25 and relays H30, III), I25 and I30. In view of these facts, the car is propelled upward continuously past intermediate station II to its destination, i. e. to station III, where it opens limit switch 31, causing the deenergization 0f relays I55 and I89, and through the latter, of relays SI and 83. With the opening of relay 5B, the motor stops so that the car is thereby brought to a halt at station III.

The priority accorded a send order by the priority relays I and ISO (the former for send orders directing the car to station III, and the latter for send orders directing the car to station I) is made strikingly apparent if it is assumed that an operator at station II signalled a call order through a depression of switch 22, at a time While the car was below this station. But for the plan of priority accorded a send order, that call should be answered by a halt of the car at station II be fore it proceeded on to station III in response to the send order as just described.

The car having been below station II at the time switch 22 was momentarily depressed, switch 25 was in the throw position with contactor 2B closed, and relay llIl was energized. A circuit accordingly was momentarily completed through switch 22, conductor 23!, contactor H2 and conductor 233, energizing relay I30. Thereupon a holding circuit for relay ISII was established through contactor III, conductor 235 and contactor I35, retaining relay 53% energized. With relays I36, I80 and IE0 energized, a circuit is provided for energization of relay I26, through contactor I35, conductor Eli and E'IQ, contactor I36 and conductor 28! and 283. Upon the energization of this relay I26, contactor I25 closes to shunt the path through conductor 2T9, contactor I36 and conductor 28L so that the energization of relay I20 can survive beyond the deenergization of relay I30 which must occur as the car passes station II, opening contactor 2-3 and deenergizing relay Hll.

Since the circuit conditions set up through the energization of relay ISII caused the energization of relay 60 independently of any of relays I66, I III, I20 and I3Il, the setting up of these holding circuits in relays I39 and I29 is prevented from affecting the operation of the dumbwaiter car propulsion system until it has proceeded directly to station III, as ordered by the operator at station I through depression of sending switch IS while the car was at his station.

After the system has performed according to this send order and the car has reached station III, however, it must respond to the station II call. The energization circuit for relay I20, though originally established through contactor I and conductor Ell, survives after the opening of con- .221. and contaotor 82. 50 becomes energized when the predetermined postponing the downward. traction OI -tactor I85 at the time o' rrival of the car at station III, because relay l lilis energized through .ductor 285 and contactor I25, is just the same in all respects as would have resulted from a momentary depression of the button 21. at a time when the car was at rest at station III. The car being now at station III and relays I86, I2?) and 90 being energized (the latter being supplied coil current through switch conductors 28? and 28.9 and contac'tor' li); a circuit is established from the positive supply conductor through contactors I3? and MI, conductor 24!, contactor I03, conductors 29! and 293, contactor I23, conductor Through this path, relay time for the reclosing of contactor II has elapsed and switches 9, I9,'29 and 59 are closed.

At the energization of relay iii}, the motor operates in the direction to cause the descent of'the .car, and this continues until the car reaches station .II, cam 6 (Fig. 1) engaging switch and opening contactor 2i, and causing the deenergization of relay lllil. This produces multiple breaks in the positive supply circuit to the coil of relay 56, one break being caused by the opening of contactor IIl3in the circuit between contactor I31 and conductor 221, and a further break being made in the circuit by the opening of oontactor I23 when relay I29 is deenergized by the opening of cont-actor IflI. The car is thus stopped at station II with contactor 28 closed and relay IiB energized, but with the remaining relays in the system open.

With the system in this condition, if a call were placed at station I by a momentary depression of switch I I, it would set up a holding circuit in relay I'IG through lower limit switch !'I, resulting in energization of relays I40, 93 and 59, and, through the latter, downward-drive operation of the motor, bringing the car to station I. If instead a call were placed at station III through switch 33, it would result in energization of relays I60, I50, 80 and 6t, and the car would be brought upward to station III. If two such orders were.

placed in succession, the first call order to be signalled would be obeyed in the manner just de scribed and then the other would be obeyed after closure of contactor II and switches 53, I9, 29

and 3-5.

If a send order were signalled at station II when the car was at this station, as through a momentary depression switch 23, this order would prevail over any competing ordene. over a call signalled through switch i! prior to the depression of switch 23. Whereas the call signalled through. switch I! would have set up a holding circuit in relay I I6, and, through contactors I85, III and H2, would have established energization of relays MK! and and would have established a positive supply circuit up to the coil of relay 58, the depression of send switch would institute the energizationof relay I813, opening contactor I85, deenergizing relays Mil and 9t, and the car in response to the order signalled through switch II. Note, however, that the holding circuit through contactor I'Ii would remain intact. The system operation in response to a send order sistnalled from intermediate station II is just the fix same as in response to a send order from one terstation to the other, in that one of the y'rela operated, causing operation in turn of the associate terminal-call holding relay and motor control relay. Thus, the operation in response to the order signalled through switch 23 would correspond to that described above as resulting from 2. send order signailed through switch I3 wish the car was at station I.

The feature of response of the system to a plurality of calls, not necessarily in the time order inwhich they were signalled but instead. in the physical order oi the stations to which the car is called with respect to the direction of progress of the car, isillustrated by assuming the car on route downward to station II from station III,

and supposing that a call is placed through switch and th n a c 11 is placed through switch I I.

The car being above station II, contactor 21 is closed and relay iil lis energized. Energization of relay I28, having been previously instituted by current momentaril provided through its coil, e. g. through switch 22, conductors 235 and 295, contactor I62 and. conductor 29?, is sustained by a holding circuit through contactor IIlI, conduccr 285 and contact/or I25. Relays -90 and 50 are energized, the former through contactors I81, I97, H93, 52% and the latter through contac'tors I37, Ii l, I23 and 82. The energization circuits of relays 9t and 59 all. are now dependent upon paths through contactors of rel y IE6; and once, upon the car reachingstation II and throwing switch 26 to the opposite throw position, the operation oi the car will bc interrupted.

Now, during the downward movement of the car toward station II, suppose an operator at station III momentarily depresses switch 33 to call the car. This actuates relay IEO, setting up a holding circuit therein through contactor I6I and limit switch 51'. Through contactors I and l 62 and 53 I, relay IE6 is energized, and conductor 26? is brought to the positive supply potential through contactors IEiI and I32. This does not result in immediate energization of relay 65, however, since relay 98 is energized and has contactor 92 open specifically for blocking such premature energization of relay Through contact I536 and I63, conductor 21I is brought to the positive supply potential, but open contactor @I prevents this condition from resulting an immediate energization of relay I55! and consequent premature interruption of the downward movement of the car.

If further order were signalled, the car would be made to n ceed to station II and stop and after the predetermined time interval had elapsed, it would be made to go back up to station III. Assuming, howover, that a station I call was signalled through switch I! after the station I call signal and before the car reached station 11, relay I'lii would be momentarily energized, establishing its holding circuit through contactor H3 and limit switch II, and providing an alternative path through conductor 203, con-- tactor I855, conductor 2| I, and contactor I12 and conductor M5 for retaining direction supervising relay 99 energized after the interruption of the energization path through contactors I 81, I91, and upon the car reaching station II and opening the circuits of relay I00.

This circuit established through holding relay H0 is such as to take precedence over the circuits through relay i530, since it is able to retain. down "direction control through the continuation of the energization of relay 00. However, it is not able to establish an alternative supply circuit for relay 50 immediatelyif it were permitted to do so, it would cause the car to pass by station II without stopping, and this would violate an objective of the system. Holding relay H can provide for the energization of relay 50 only through an intermediate relay, viz. through the energization of relay I40. The current path required for the energization of relay Hill is traced through contactors I13, I86, III and I2I, the last-named contactor being held open so long as relay I is energized.

When the car reaches station II, it transfers the arms of switch 38 to the positions with contactor 27 open and contactor 28 closed. This deenergizes relay I00, and the deenergization of relay I00 in turn causes the simultaneous deenergizations of relays I20 and 50. Almost instantaneously upon these simultaneous deenergizations, contactor 53 opens, so that energization of a motor relay cannot now be reinstituted until the predetermined time for the reclosing of con-- tactor 'II has expired. An instant later, the armature of relay I20 reaches its reclosed position, with contactor IZI now closed, and through this contactor relay I40 is thereupon energized. Now, contactor MI being closed, a path is provided through this contactor, contactor I22 and conductor 22'! and contactor 02 for restoring the upper end of the coil of relay 50 to the positive supply potential, so that the rela 50 will again be operated to provide further downward car movement when contactor II and switches 9, I9, 29 and 39 are again closed.

The purpose of relay [4| is apparent in the foregoing explanation of the sequence of events occurring with the system responding to a down call to station II when a further down call is signalled in for bringing the car to station I. Relay I10 must hold this further order, but without the completion of the circuit down to the motor control relay, and the latter circuit must not be completed until the motor control relay 50 has been deenergized momentarily to permit contactor 53 to be momentarily opened. This very brief delay in reenergization of the motor control relay is assured by the activation time of relay I40.

The operation and purpose of relay I50, in relation to a station III call order signalled during progress of the car from station I to station II, and in circuit relations with relays I00 and I50 corresponds in all material respects with that described above in connection with relay I40.

The station III call, which in the assumed set of operating conditions was taken to have been signalled through switch 33 before the station I order was signalled through switch ll, though postponed from taking efiect after arrival of the car at station II in view of the fact that a further down call order was signalled in while the car descended toward station II, is retained throughout the time of the downward movements of the car, relay I00 remaining energized in its holding circuit throughout this time, and relay I50 being energized through contactor I02 and conductor 299. Upon arrival of the car at station I, the opening of limit swit :i I! opens the holding circuit of relay I I0, and the energization of relays 90, 50 and I40 is stopped.

With the deenergization of relay 90, contactor BI is reclosed, so that relay 80 is energized, and contactor 02 is also reclosed so that the upper end of the coil of relay 00 is brought to the positive supply potential. Then, when contactor II and switches 9, I0, 20 and 39 are all closed, the car will be made to proceed upward to station III by the energization of relay 00, this upward movement to be halted only by the attainment of the station III position and the opening of the upper limit switch 31, unless a station II call is signalled to the car before it has passed by station II. Such an intervening order signal would be obeyed by a halt of the car en route to station III, in keeping with the plan of the system to respond to calls not necessarily in the order signalled, but in the order of reaching the calling station in the direction of progress.

From the foregoing description of the dumbwaiter system illustrated in Fig. 2, and from the several examples given of signalling situations which may be encountered therewith and the manners in which the system responds to them, it will be understood that at each station, a car calling button is provided, operable at any time, but incapable of exercising any super-control on the system. A call through such a switch will be answered after all send orders have been fulfilled and when the car has arrived at each preceding station to which it has been called, in the order determined by its direction of movement. Also, at each station is provided one button switch for sending the car to each of the other stations served by the system. A car-operated switch is provided at each station in series with these sendorder switches, to prevent mischievous or inadvertent sending from a station other than that at which the car is located at the time the operator works the signal buttons.

An operator at the station at which the car is located can employ either of the send buttons located there to send the car to any selected one of the other stations, and in doing so, compels the car to proceed immediately to such selected station irrespective of any other calls already in the system or signalled while the car is en route in obedience to the send order.

In Figs. 3 and 4A and 4-13 is illustrated a multi-station dumbwaiter system generally like that of Figs. 1 and 2, but with four stations.

The control system of Figs. 3, 4-A and 4-33 is arranged generally along the lines of the control systems of Figs. 1 and 2, but is different therefrom in the following respects:

Relays 50, I50, I0, 80, 90, I00, Ila, I40, I50, I60 and no are employed in Figs. lA and 4-H just as in Fig. 2. Similarly, lower and upper lim t switches II and 3'! are provided at lowermost station and the uppermost station, and the double-throw switch 20 is retained at intermediate station II. Relays I20 and its of Fig. 2 are replaced by relays 32 and 335i having an additional contactor on each; and the second intermediate station, station III, is provided with a double-throw switch 3H3 and six relays, 309,

SH}, 359-, 3'10, 3 lfl'and corresponding 26 and relays Hi6, H0, 3%, Mt respectively, at station-II.

The two priority relays i for express handling of the tactors, and two additional p1.erity relays 32s and 430 are added. Relays Md, 42d, and d ll? handle priority operations directing the car to stations I, II, III and IV, respectively.

Car cam operated switches iii and pro vided as before at the terninal stations, and switches l8- and. 38 have been at terminal stations I and IV, respectively, to be'nermally closed out to he opener by engage i ment of car cam 5 ahead of switches in and respectively.

The station signal switches I Eli-2i, 3|34- and added switches l-fi l are each dc nated, as before, by a first digit denoting station at which the switch is located 0nd digit denoting the station to which it orders the car to travel. As before, cam-operated switches i5, and 3E, and newly added switch A5 are arranged to prevent priority send orders placed from a station when the car is not positioned at the send-switch station.

Emergency calling switches M14 are shown added at the respective st Figs. 4-A and l-B, and moreover, a I control switches is shown provided in the car, one nopriority switch and one priorit switch for directing the car to each of the stations. I will he appreciated that a three-step system such as shown in Fig. 2 may readily h emergency call switches such as 5i? i and and with car switches such as i, 452,453, 365,6162 and 463, neither of these features being limited in any way to a four-station system.

As with the system of Figs. 1 2, the 4-station arrangement of Figs. 3, i not require the benefit of the prior clay tures for those orders directin the car from a terminal station to the adjacent intermediate station, i. e. from station I to station II or from station IV to station III, but the priorit relays are used for all other send orders as well as for emergency call orders placeable through emergency switches mi, 302, Mill 443 5.

The double bank of switches in the car is a feature making possible the use of this control system for elevator purposes as well as for a mere cargo conveying system of the dumowaiter type. Moreover, with express sending switches 45!, 552, 453 and 454 in the car, the sending switches at the stations, such as switches l2, and ii at station I may be eliminated. if desired. Thus four priority send switches 45!, 452, 453 and 56 in the car may used in a -station system to replace twelve fixedly mounted send switches, such as switches i2, i3 and id at station I and switches 2|, 23 and 2d at station II. Obviously, a send order can only be placed throu h the switches in bank 450 by an operator at the station at which the ear is then considering the system as applied to a dumhvv .iter, since anyone at any other station lacks immediate access to the interior of the car.

The connections of priority relays and l correspond most closely with those of the priority clays I80 and E99, respectively, of Fig. 2, the differences being merely addition of further contactors to provide for the required interconnections with relays 420 and 53B.

The important features of performance of the Ilfl was.

system of Figs. 3, i-A. and 443 according to the principles of answering regular (no-priority) calls in the turn corresponding to the physical order of the call stations taking into account the direction of travel of the car, storing all cells so long as they remain unanswered, and pr viding for supersecling or by-pass or priority operation where the car is being sent for one station to another, are set forth by discussion of the operation. of the system in response to va ty of signals. Suppose that th car is at station IV, and a station I call signal is placed through switch l 5. Continuing, suppose that the car is proceeding downward in response to this call, between station III and station II, when two further calls are placed in close succession, a station III call through switch and then a station II call through switch 22. The station III call will not interrupt the downward movement of the car, but the station II call will halt the car in its downward trip.

Still further, suppose that after resumption of the downward travel from station II, an emergency call to station IV is signalled through switch 384, and suppose that the operator at this station, upon gaining access to the car, loads it with material urgently needed at station II, and presses either switch 42 or switch 452 to send the car non-stop to station II. Assuming that no further orders are placed, the car, after proceeding directly to station II in compliance with the send order, will then go on to station I, and finally it will go to station III. The way in which the system is made to accommodate such a variety of signals and to provide full eventual compliance with all of the signals, will now he explained in detail.

With the depression of switch H, the coil of relay HE} is momentarily energized through the circuit including switch H, conductor MI, and lower limit switch H. The holding circuit is thereupon established through contactor H3, retaining relay l'lii closed. Relays H9, and M0 are all deenergized. Th circuit from the positive (lower) terminal of the coil of relay 110 is extended through conductor 113, contactors 428i, 435 and M92 and conductor M5 to contactors ill and H2. Through contactor I72, the positive supply voltage is carried through conductor ll? and through contactor Hi to the coil of relay 90, energizing relay 9!) and making possible a circuit for relay 56. Through contactor I'll, the circuit is extended through conductor 5'59 to contactor 322, through which the coil of relay M3 is energized. Now through conductor 48! and contactor Ml, the positive supply circuit is further extended through contactor 32! and conductor 4 -83 to contactor 3'62, and through this contactor to the coil of relay 3 35]. Through conductor 6S5, contactors 34! and 36! and conductor 681, the positive supply circuit is then extended to contactor 92 and through this contactor to the coil of the dovm-direction motor operation relay energizing this relay and thus causing the motor to operate to drive the car downward.

If no further order were signalled during the descent of the car, it would be driven continuously down to station I, the circuits inclu. ng re vs ilil, Mil, 34B, 64'} and 5!! remaining intact until arrival of the car at the lowermost station, at which cam i would open switch ll to interrupt the holding circuit of relay HQ and cause relays EM, 34-8, 9!! and to be deenergizecl as a consequence, stopping the motor.

I-Iowever, continuing with. the above assumed interval assured by mechanism 12. .car is stopped at station II in response to the illustrative conditions, switch 33 is operated while the car is descending between station III and station II. The momentary depression of switch 33 carries the positive supply voltage over conductors 49! and 5I2 to contactors 30! and 3! I. The car having passed beyond (below) station III, switch 3I6 is in the throw with contactor 3I1 open and contactor 3I8 closed, so that relay 310 is energized and contactors 3! I, 3I2 and 3!3 are closed. Conversely, contactors 30!, 302 and 303 are open at this time. Therefore, the circuit through conductors 49! and 5I2 is continued through contactor 3!! and conductor 493 to the coil of relay 310, which accordingly is energized. Itis to be noted, however, that this energization of relay 310, resulting in establishment of a holding circuit through conductor 495 and contactors 3! 2 and 315, does not affect any of the circuits which are active in causing the descent of the car, so that the motor continues to drive the car unchecked toward station I.

Going still further in accordance with the assumed set of signals, switch 22 is depressed momentarily while the car is yet in transit between station III and station II. This brings conductor 491 to the positive supply potential, and accordingly applies this potential to contactors I! and I I I. The car being above station II, contactor 21 is closed and contactor 28 is yet open, so that contactors I0! I02 and I03 are closed and contactors III, H2 and H3 are open. Accordingly, the coil of relay 320 is momentarily energized through contactor I0! and conductor 499, and the holding circuit for retaining this relay energized is established through conductor 50! and contactors I02 and 325. With the energization of relay 320, contactors 32! and 322 are opened, causing deenergization of relay I40, but conductor 483 is held at the positive supply potential through contactors 445, 433 and M5, conductor 503, contactor I03, conductor 505, and contactor 323. An alternative path for the positive supply potential existent as a result of the continued holding condition of relay I10, is traced through conductor 411, conductor 501, and contactors 324 and 323.

When the car reaches station II, it transfers the arms of switch 26 to neutral, opening contactor 21. With the opening of contactor 21, contactors IOI, I02 and I03 are opened, and the supply circuit of relay 320 is broken. This causes the opening of contactors 323 and 324, interrupting the positive potential supply circuit of conductor 483, contactor 362, and relay 340, and

hence opening the supply circuit of relay 50. In

the time interval required for the reclosing of contactors 32! and 322 and the reenergization of relay I40, and the ensuing reenergization of relay 340 through the circuits maintained through contactors I1! and I12 by the continued holding of relay I10, ample time is provided for the armature of relay 5% to drop to its idle position, so that contactor 53 is opened and the supply circuit of relay 50 is rendered incapable of being reclosed until the predetermined delay time Thus, the

signal given through switch 22, prior to its continuance downward to respond to the original call through switch II. Direction control relay 90 remains energized all this while through contactor I12, conductor 411, and contactor 8!,

, blocking relays 30 and 60.

.When the predetermined delay time has elapsed and contactor 1! is reclosed, and switches 9 and is 29 both are closed, the circuit maintained through contactors I1! and I12 by the continued holding of relay I10 again provides for energization of relay through the path formerly traced through conductor 419, contactor 322, relay I40, conductor 483, relay 340 and conductor 481, so that the car is made to resume its downward journey toward station I.

According to the fourth of the assumed signalling operations, emergency call switch 404 is momentarily depressed while the car is en route from station II to station I. Through this switch, conductor 5H is brought to the positive supply potential, and through switch 38, conductor 5I3 is similarly brought to this voltage. A circuit is now established thence through conductor 5I5 and contactors 434, 424 and M6 for the momentary energization of priority control relay 440. With this momentary energization of relay 440, contactor 44! is closed, energizing relay I60 momentarily so that a holding circuit therefor is established through contactor I6! and upper limit switch 31. Through contactors 4H, 42! and 439I, and thence through contactors I62 and I33, three conductors 523, 525 and 53! are all brought to the positive supply potential. Through conductor 53! and contactor 446, the circuit for energization of relay 440 through contactors 434, 424 and M9 is held complete, holding relay 440 energized until the car shall arrive at station IV and open switch 31.

At the energization of relay 440, the opening of contactor 4492 breaks all circuits through relay !10 except its holding circuit through contactor I13. Therefore, the positive potential supply to conductors 411 and 419 is broken, and relays I40, 343, 50 and 90 are deenergized. With the deenergization of relay 90, contactor 9! recloses, and now down-direction blocking relay 80 is energized. The opening of contactors 441, 448 and 449 prevents energization of any of the other priority relays so long as relay 440 is held energized.

Through contactor 449I, conductor 521 and newly closed contactor 02, up-direction motor supply relay 60 is energized as soon as the delay period of mechanism 12 has passed, starting the car on its ascent toward station IV.

The opening of contactors 444 and 445 prevents the energization of any circuits through any of contactors I93, H3, 303 and 3!3 so long as relay 440 remains energized.

The closure of contactors 442 and 443 places conductors 55! and 563 at the positive supply potential. Conductor 56! leads to contactors 366 and 311, and conductor 563 leads to contactors 326 and 331. Relay 310 being held energized through the circuit including contactors 3I2 and 315, contactor 311 is closed, and therefore relay 360 is now energized through contactors 443 and 442, conductor 56! and contactor 311.

The energization circuit of relay 60 being completed directly through relays 440 and I60 and being independent of relay 360, the car will not be stopped at station III, but will continue past this station to station IV. As it passes station III, cam 5 nevertheless engages switch 3I6 and throws it to the position with contactor 3I8 open and contactor 3!! closed, so that relay 300 is energized and relays 3I0 and 319 are deenergized. Now, with the car above station III, the updirection car call holding condition, until now maintained in relay 310, has been discarded and replaced by a down-direction car call holding condition in relay 360.

With the conditions as just described, the car has been halted in its descent between station II and station I, has been delayed at an intermediate position in the hatchway for the brief interval for which mechanism '12 is preset, and has thereupon been lifted directly to station IV; and while this process was being carried out, the unanswered. call to station I has been held stored in relay I10, and the unanswered call to station III, formerly held in relay 310 to bring the car up to the station, has been retained as a downcall held in relay 363.

The car is of course halted at terminal station IV at the opening of switch 3'1, and it is retained at this station for the delay period assured by delay relay '10. If the emergency call to station IV is merely an emergency recall to extract from the car something which should earlier have been taken therefrom, and if no send order Were placed in the system by the operator at station IV, then the station III call could next be answered by the car, and thereafter it would proceed to station I. However, in the assumed set of circumstances, a fifth signalling operation involved the momentary depression of switch 42 by the operator at station IV who had made the emergency call, Such a signalling operation is available to him for the purpose of sending the car directl to a destination of his choice, e. g. station II, regardless of the other calls such as those of station III and station I remaining stored in the system.

With the depression of switch 42 while the car is at station IV and cam 5 holds switch 45 closed (the depression of switch 452 in the car would yield just the same result) conductor 541 is brought to the positive supply potential, and. through this conductor and contactors 431, 459 and 41", relay 426 is momentarily energized. During this momentary energization, contactor 222 brings conductor 543 to the positive supply potential; energizing relay 3'16 through contactor 367, and contactor 429 brings conductor 49: to the positive supply potential. Through the latter conductor, a circuit is completed through one of contactors 101 and 111; in the present instance, the car being above station II, contactor 2'? is closed and relay 166 is energized, so that contactor lill is closed and down call holding relay 3213 is momentarily energized therethroug-h. The holding circuit for relay 32?.- is completed through contactor Hi2 and contactor 325. Through contactors 445, 433 and 415, conductor 583, contactor Hi3, conductor 535 and contactor 324, the previously described circuits are energized for maintaining coil 90 energized.

The circuit for holding relay 423 energized is now traced from conductor 505 through contactors 323, 325i conductor e15, contactors 421, 432, 449 and 419 to the coil of relay 429. Another circuit is traced through contactors 421 and 428, conductor 51 1, contactor 328, to conductor 481, through contactor e2 to the coil of relay 50, for downward motor propulsion of the car.

' With the operation of double-throw switch 26, relay 199 is deenergized and relay 321i is in turn deenergized, and the holding circuit for relay 420 also is broken. Thus the car has been brought to station II and stopped there, and the holding circuits including relay 42s for bringing. it directly to this station have been erased.

There remain to be fulfilled the calls held for stations I and III. The call to station I will be answered first since the operation of the car in the last phase was in the downward direction,

away from station III and toward station I, and updirection blocking relay 99 is continued in its energized condition throughcontactors i72 4211, 439, 4492, 1'12 and 31. When the use of the car at station II has been completed and switches El and 29 are closed and contactor i1 is recloscd, the circuits held through relay 1'1!) and contactors 421 1 43.9 and 4492 are once more effective through operation of relays 8,0, 140 and 3,411 to cause the energization of relay 58 and the, consequent downward; drive of the motor bringing the car to station I, where these circuits are all broken through the opening of the lower limit switch 11, and relay 852 is energized to insure that relay will remain open and that the next operation of the car will be an ascent instituted through relay 60.

Now, at station III, contactor 31'1- is open and contactor 318; isv closed, and relay 310 is energized with contactors 3,11, 312 and 3113 closed as a result. Relay 3% is now also held energized through the circuit including conductor 495, contactor 312 and contactor 315. Upon completion of the use of the car at station I, and with switches 9 and 19 closed and contactor 1.1 reclosed following the time interval for which mechanism 12 is preadjusted, the positive supply circuit ;for relay 58 is established through contactors 4,44, 423 and 414, conductor 5'11, conductor 513, contactor 313, conductor 5'15, contactor 3'13, conductor 5T1, contactor 332 (with consequent energization of relay 1.56), contactors 151 and 331., conductor 5'19 and contactor 82 to the coil of relay 6i This provides for the upward drive. of the car, and these circuits remain unchanged until the car reaches station III. Car cam B. there transfers the arms of switch 316 to, open contactor 318, opening the circuits of relay 316. and relay 370 in turn, and breaking the supply circuit of relay 60 to arrest the operation of the car drive motor with the car at station III. The system is now left in readiness for any further use, and any further uses thereof will be carried out in accordance with the general principles which are illustrated with the foregoing examples.

While the fixed-station send switches located at the respective terminals for sending the. car to the respective next stations, as switch 33 for sending the car from station IV to station III or switch 12 for sending the car from station I to. station II, are shown connected to operate directly upon the intermediate station call holding circuits 368 and 330, without reliance upon the priority-assurance relays 438 and 420, respectively, such send switches could be connected for operation through the priority relays if desired. When the car is at a terminal station, it is necessary that the direction 01' next operation must be to the next station, but it is possible that an emergency call signal or a signal placed in the car if used for elevator purposes may override the send order placed through switch 43 or switch 12, connected as shown, and cause the car to by-pass this station.

In any event, the express switches 452 and 453 in the car must be connected for operation through the express relays 420 and 430, since these switches must operate properly regardless of the location of the car at the time of signalling an order through one of these switches. If the car is at station I and it is desired that it be sent directly and immediately to station II by a signal placed in the car, the appropriate switch 452 is momentarily depressed. Through conductor the contactors 431, 449 and M9, the coil of relay 420 is momentarily energized. Then, through contactor 429, conductor 491, contactor Ill (closed because the car is beneath station II and relay 1 I0 is energized through contactor 28), relay 330 is energized, and a holding circuit therefor is provided through contactors H2 and 335.

A positive-supply energization circuit is now traceable through contactors 445, 433, and M5, conductor 503, contactor H3, and contactor 334, to conductor 523. Through the latter, downdirection blocking relay 80 is energized.

Another circuit is established through contactors 445, 433, M5, conductor 503, and contactor I I3 to contactor 333. From contactor 333, one circuit continues to the coil of relay 60, through conductor 519 and contactor 82, providing for upward propulsion. From contactor 333 another circuit is traced through contactor 339, conductor 6|5, through contactors 421, 431, 449 and M9 to the coil of relay 420, holding this relay energized.

Yet a further circuit is established from contactor 333 through contactor 339, via conductor 6 l 5, through contactors 421 and 428, through conductor 6l1, contactors 338 and 82 to the coil of relay 60, an alternative circuit available for directional control where more than two intermediate stations are provided.

The above-described holding circuit for relay 420 will be retained energized until the car arrives at station II and opens contactor 23, causing relay H0 to be de-energized, in turn opening the holding circuit of relay 338, and consequently opening the holding circuit of relay 420. For this type of operation of the car, the important function of relay 420 is to block the energization of any other of the priority control relays M0, 430 and 449 through the opening of contactors 425, 426 and 424, respectively.

As mentioned above, such operation through the intermediate station priority relays 420, 430 may be provided in connection with switches l2 and 43, these switches being connected in shunt with switches 452 and 453 for this purpose and producing operation in the manner just described, instead of their connections in parallel with switches 22 and 33, respectively, as shown in the drawings.

No details of the car propelling system have been shown in the drawings, as any of the well known car hoisting and lowering systems can be used, as for example, an electric motor system or an hydraulic system. Thus, the motor control relays 50 and 68 shown in the various embodiments of the invention may be employed to control the directional power circuits of a reversible alternating current motor or those of a reversible direct current motor, or they may be employed to control the operating valves of a hydraulic car motivating arrangement, for example.

A feature of the present invention of great importance is the freedom from interference of the express or priority control arrangements with call holding circuits for stations other than the station to which the car is directed under priority control. With this feature, calls signalled before or during the priority operation are retained held for subsequent response, except for a call to the station to which the car is directed by priority operation. Such a call as this is of course cancelled upon arrival of the car at the calling station.

To illustrate an extreme case, an operator at the station at which the car is located can call" the car and also place a send order to direct the car to another station, and the call order, whether placed before or after the send order or exactly simultaneously therewith, is given full effect, in that a non-priority car recall circuit is established, to remain intact until it has eventually returned the car to the station whence it was originally sent.

Where in the specification and claims reference is made to positioning of switches in the hatchway and operation thereof by cams upon the car, it will be appreciated that such operation may be achieved remotely from the hatchway, as in miniature geared-down and coupled relatively movable parts. As one example, a miniature dummy car may be coupled to the main car 1 for scaled-down movements along an appropriately scaled hatchway, oriented vertically or otherwise as desired, and the cams and control switches may be associated therewith to provide for greater compactness of the control circuits. Similarly, a coupled control unit bearing cams corresponding to cams 5 and 6 may be made angularly movable, if desired, with control switches placed at appropriate angles about the axis of rotation, and with suitable gearing to the car suspension system to insure the positive maintenance of the desired relations between linear car movement and the angular movement of the cam bearing unit.

Moreover, the cams 5 and 6 may be replaced if desired by units obviating physical contact with the hatchway control switches, as by photoelectric, magnetic or capacitive operating arrangements of well-known types.

In the systems of Figs. l-2 and Figs. 3-4, the cam-operated switches connected between the positive supply conductor and the send switches at the terminal stations are fully eifective to guard against an operator at a terminal station placing send orders mischievously when the car is elsewhere. The similar cam-operated switches at the intermediate stations are similarly effective under most conditions, but an operator at one of the intermediate stations, bent on mischief, can depress a send order switch and 'hold it closed while the car passes the station, and in this way establish a send order holding circuit which can make the car stop before reaching its destination and go to a different station on an entirely wasteful errand.

One way to avoid this difficulty, where the system is used only as a dumbwaiter, is to arrange the send signal blocking switches at the intermediate stations, such as switch 25 at station II, to be operated by the sliding door at the respective station, or by the guard gate which may be included on the dumbwaiter car for protection against interference of any of the material transported therein from projecting against the hatchway wall. Another way to avoid this remote possibility of trouble with the system due to mischief is to replace fixed cam 5 with a retiring cam-a cam electromagnetically operated and arranged for projection from the car only when the car is at a station.

A retiring cam arrangement is illustrated in Fig. 5 at 5', the cam element being supported on the plunger of a solenoid and being springurged into the position of projection from a suitable recess provided in the side wall of the car. The coil 5" is connected between the positive supply end (lower end) of the coil of relay 1!) and the negative supply main, so that the coil 5" is energized and cam 5' is retracted into its recess awa' ai whenever either relay- 50: or relay D. is enersized; and. thus whenever the car is moved. With this method of connection of the retiring cam, it is easily fitted. into a system according to the present invention, irrespective of the number of intermediate stations the system is arranged to serv,e. It will be readily apparent that the coil 5" need not necessarily be connected to the coilof relay. 7!}, and that the coil. 5" may be connected to; an additional set of. contactors on relays 5,6. and Edit preferred;

since, many changes could be made in the above construction and many apparently widely difierent embodiments of this invention. could be made without departing from the scope thereof, is, intended that all the matter. contained in the above description and shown inthe accompanying drawings shall be interpreted as illustrative and not in a, limiting sense.

What is claimed is:

1;. A controlsystem for a. vertical lift apparatus oi the type including'a hatchway extending between an upper, terminal station and a lower terminal station with at, least one intermediate station and with a car guided in said hatchway and motor propelled for upward and downward movement therein, the. control system comprising; means at eachof said stations for signalling callsto bring the car thereto, means for receiving said calls and holding them until fulfilled by a stop of the car at the station, directional order control means for causing the car to proceed in the direction of progress corresponding to its last direction of movement until it has made a stop for every one of the calls therebeyond in the last direction of movement and for then causing the car to proceed to answer any calls to stations in the opposite direction therefrom, means for signalling an order to send the car from a station at which it is positioned to a selected station destination, means for receiving and holding said send order until said car has stopped at said destination, and means responsive thereto for postponing response of said car to any call signals until it has stopped at said destination.

2. A control system for a vertical lift apparatus of the type including a hatchway extending between an upper terminal station and a lower terminal station with at least one intermediate station and with a car guided in said hatchway and motor propelled for upward and downward mov ment therein, the control system comprising: means at each of said stations for signalling calls to bring the car thereto, means for receiving said calls and holding them until fulfilled by a stop of the car at the station, directional order control means for causing the car to proceed in the direction of progress corresponding to its last direction of movement until it has made a stop for every one of the calls therebeyond in the last direction of movement and for then causing the car to proceed to answer any calls to stations in the opposite direction therefrom, means for signalling an order to send the car directly from a station at which it is positioned to a selected station destination, means for receiving and holding said send order until said car has stopped at said destination and for rendering said directional order control means inoperative until said car has stopped at said destination, and means operative upon the arrival of said car at said destination for reinstating operation of said car in response to calls in accordance with said directional order control means.

3. control system as defined in claim 1, wherein: said means for signalling calls comprise a call switch at the upper terminal station, a call switch at the lower terminal station, and a call switch at each. intermediate station; said call receiving and holding means comprise a holding relay coupled to said upper terminal station call switch, a. holding relay coupled to said lower terminal station call switch and means for holding a call. circuit for each intermediate station for the direction. in which the car must come thereto, each said holding relays including a, contactor. for actuation of the motor control circuits; said means for receiving and holding said send order comprises a holding relay responsive to; said send order signalling means; and said means. responsive thereto for postponing response of said comprises contactor means on said send order responsive holding relay for blocking the circuits of said contactors on said call; holding relays.

A control system as defined in claim 2 ein: said directional order control means see a down direction control circuit blocking relay and an up direction control circuit blocking relay, each relay including a normally closed contactor in. series with the actuation circuit of the other whereby either relay, upon actuation, blocks the energization of the other so long as. the first remains. actuated; the control system. including connections between the actuation c'rcuit of th up direction blocking relay and the down direction holding relays for the inte'mediate and lower terminal stations, and connections between the actuation circuit of the down direction blocking relay and the up direction holding relays for the intermediate and upper terminal stations.

5, A control system for a vertical lift apparatus of the type including a hatchway extending between, an. upper terminal station and a lower terminal station with at least one intermediate station; and with a car guided in said hatchway and motor propelled for upward and downward Inoyement therein, the control system comprising; meansat each. of said stations for signalling calls to bring the car thereto, means for receiving said calls and holding each call until fulfilled by a stop of the car at the call station, directional order control meansfor causing the 'car to proceed in one direction and stop at each call station reachedin that direction until. no further calling stations lie ahead, means for holding the car at each station at which it stops for a predetermined minimum period, means for signalling an order to send the car from a station at which. it is positioned to any selected station destin tion, means for receiving and holding said send order until said car has stopped at said destination, and means responsive thereto for postponing response of said car to any call sign a l s until it has stopped at said destination.

6. A, control system as defined in claim 5, wherein said means for holding the car at each station; at which it stops for a predetermined minimum period comprises a time delay relay connected to be energized concurrently with the carpropelling motor and including normally closed contactor means for blocking the establishment of a, motor actuating circuit until the delay relay has reclosed, said delay relay also including a reclosing delay mechanism for holding said contactor open a predetermined period of time after cessation of energization of said delay relay.

7. A control system for a vertical lift apparatus ofthe type including a hatchway extending between an upper terminal station and a lower terminal station with at least one intermediate station and with a car guided in said hatchway and motor propelled for upward and downward movement therein, the control system comprising: means at each of said stations for signalling calls to bring the car thereto, means for receiving and holding each call until fulfilled by a stop of the car at the call station, directional order control means for causing the car to proceed in one direction and stop at each call station reached in that direction'until no further call station lies ahead in that direction, means for holding the car at each station at which it is stopped for a predetermined minimum waiting period, means for signalling an order to send the car from a station at which it is positioned to any selected station destination, means for receiving and holding said send order until the car has arrived at said destination, means responsivethereto for postponing response of said car to call signals until it has arrived at said destination, and emergency call signalling means coupled to saidsend order receiving and holding means to provide for priority calls to be given immediate and direct response ahead of ordinary calls.

8. A control system for a vertical lift apparatus of the type including a hatchway extending between an upper terminal station and a lower terminal station with at least one intermediate station and with a car guided in said hatchway and motor propelled for upward and downward movement therein, the control system comprising: means at each of said stations for signalling calls to bring the car thereto, means for receiving and holding each call until fulfilled by a stop of the car at the call station, directional order control means for causing the car to proceed in one direction and stop at each call station reached in that direction until no further call station lies ahead in that direction, means for holding the car at each station at which it is stopped for a predetermined minimum waiting period, means for signalling an order to send the car from a station at which it is positioned to any selected station destination, means for receiving and holding said send order until the car has arrived at said destination, and means responsive thereto for postponing response of said car to call signals until it has arrived at said destination, said means for signalling an order to send the car comprising at least one signalling switch at each of a plurality of stations, and means blocking circuit actuation through all send order signalling switches other than those at a station at which the car is positioned.

9. A control system as defined in claim 8, wherein said means blocking circuit actuation comprises a normally open cam switch at each station in series with the send switches thereat, and cam means on the car for closing said cam switch when the car arrives at the station.

10. A control system as defined in claim 9, wherein the cam means on the car comprises a retiring cam, and means positioning said retiring cam for actuation of the series switch at a station when the car is stopped at the station, but keeping the cam retired or retracted when the car is in transit.

11. A control system .for a vertical lift apparatus of the type including a hatchway extending between an upper terminal station and a lower terminal station with at least one intermediate station and with a car guided in said hatchway and motor propelled for upward and downward move ment therein, the control system comprising: means at each of said stations for signalling calls to bring the car thereto, means for receiving and holding each call until fulfilled by a stop of the car at the call station, directional order control means for causing the car to proceed in one direction and stop at each call station reached in that direction until no further call station lies ahead in that direction, means for holding the car at each station at which it is stopped for a predetermined minimum waiting period, means including send order signalling switches in the car for signalling an order to send the car from a station at which it is positioned to any selected station destination, means for receiving and holding said send order until the car has arrived at said destination, and means responsive thereto for postponing response of said car to call signals until it has arrived at said destination.

12. A control system for a vertical lift apparatus as defined in claim 11, further including at least one additional switch in the car for registering a non-priority sending order to set up a holding circuit corresponding to a call signal for the floor to which said additional switch is to direct the car.

13. A control system for a vertical lift apparatus of the type including a hatchway extending between an uppermost station and a lowermost station with at least one intermediate station and with a car guided in said hatchway and motor propelled for upward and downward movement therein, the control system comprising: means at each of said stations for signalling a call to bring the car thereto, means for receiving and holding each call until fulfilled by a stop of the car at the call station, directional order control means for causing the car to proceed in one direction and stop at each call station reached in that direction until no further call station lies ahead in that direction, means for holding the car at each station at which it is stopped for a predetermined minimum waiting period, means including a plurality of send order signalling switches in the car, one for each station destination, for signalling an order to send the car to any selected station destination, means for receiving and holding said send order until the car has arrived at said destination, means responsive thereto for postponing response of said car to call signals until it has arrived at said destination, and means for preventing establishment of any further send order holding circuit for any other destination until the car has arrived at said selected station destination.

14. A control system for a vertical lift apparatus of the type including a hatchway extending between an upper terminal station and a lower terminal station with at least one intermediate station and with a car guided in said hatchway and motor propelled for upward and downward movement therein, the control system comprising: means at each of said stations for signalling a call to bring the car thereto, means associated with each station for receiving and holding a call until fulfilled by a stop of the car at the call station, directional order control means for causing the car to proceed in one direction and stop at each station reached in that direction until no further call station lies ahead in that direction, and thereafter permitting the car to respond to calls in the opposite direction, means for signalling an order to send the car from astation at which it is positioned to a selected station destination, means for receiving and holding said send order until said car has proceededto and stopped at said destination, and means responsive thereto for postponing response of said car to any call signals until it has stopped at said destination and for causing the car drive motor to propel the car directly to said destination, said last-named means being coupled to the call receiving and holding means for the other stations than said destination to postpone response thereto but permitting calls held in those receiving and holding means to be retained intact and further calls to be signalled effectively-during response of the car to the send order.

'15. A control system for a vertical lift apparatus of the type including a hatchway extending between an upper terminal station and a lower terminal station with at least one intermediate station and with a car guided in said hatchway and motor propelled for upward and downward movement therein, the control system comprising: means-at each of said stations for signalling calls "to bring the car thereto, means for receiving said calls and holding them until fulfilled by 'a stop of the car xatthe station, directional order control means for causing the car to proceed in the direction of progress corresponding to its last direction of movement until it has made a stop for every one of the calls therebeyond in the last direction of movement and for then causing the car to proceed to answer any calls to stations in the opposite direction "therefrom, means including a plurality of send order signalling switches in the car, one for each station destination to which the car may be sent, for signalling an order to send thecar to any selected destination, means for receiving and holding said send order until the car has arrived at said destination, means responsive thereto for postponing response of said-car to call signals until it has arrived at said destination but leaving intact all calls previously signalled and 'held except "a call for the destination and permitting further effective call signalling during the response to the send order, and means responsive to said send order receiving and holding means for causing the car to be propelled directly 'to that destination.

16. .A'control system for a vertical lift apparatus of the type including a hatchway extending between an upper terminal station and a lower terminal station with at least one intermediate station and with a car guided in said hatchway and motor propelled for upward and downward movement therein, the control system comprising: Lmeans at-each of saidstations for-signalling calls to bring the car thereto, means 'for receivingand holdingeach call until'fulfilled by a stop of the car at the call station, directional order control means for causing the car to proceed in one direction and stop at each call station reached in that direction until no further call station lies ahead in that direction, means including a plurality o'filoor selection switches for signalling an order to send the car directly to a selected station destination, means coupled to'each of said floor selection switches for receiving and holding a send order signalled therethrough until the car has arrived at the corresponding station destination, means responsive to a send order for blocking response to all calls until the car has arrived at said corresponding station destination but leaving all calls from stations other than the destination signalled prior to the arrival of the carat said destination heid intact to be answered thereafter, and means responsive to a first signalled send order for blockin the holding of any further send order until the car has arr ved at the station destination of the first signalled send order.

l7. A control system for a vertical l t apparatus of the type including a hatchway extending between an upper terminal station and a lower terminal station with at least one intermediate station and with a car guided in said hatchway and motor propelled for upward and downward movement therein, the total number of stations being represented as n, the control system comprising: means at each of said 11 stations for signalling calls to bring the car thereto, means for receiving and holding each 'call until fulfilled by a stop of the car at the call station, directional order control means for causing the car to proceed in one direction and stop at each call station reached in that direction until no further call station lies ahead in that direction, means including n floor selection switches for signalling orders to send the car directly to a selected station destination, means coupled to each of said Floor selection switches for receiving and holding a send order signalled therethrough until the car has arrived at the corresponding station destination, means responsive to a send order for blocking response to all calls until the car has arrived at said corresponding station destination but leaving all calls signalled prior to the arrival of the car at said corresponding station destination held intact to be answered thereafter, emergency call means for at least one of said tions for actuating all means actuata'ole through the floor selection switch for signalling orders to send the car to said one of the stations, and means for limiting the response of said means coupled to each of said floor selection switches to the first of the send orders and emergency call orders signalled until such first order has been fulfilled.

18. A control system for a vertical lift apparatus as defined in claim 17, wherein said send order receiving and holding means comprises it send order holding relays, one for each station, each send order holding relay having an actuation coil coupled to the send order signalling means for the corresponding station and having a holding circuit contactor connected thereto and having further contactor for isolating said call receiving and holding means from the motor control circuits and for actuating said control circuits directly until the car has arrived at the destination.

'19. A control system for a vertical lift apparatus as defined in claim 13, wherein at least one of said floor selection switches for signalling orders to send'the car is located at a station, and means is provided in circuit with this iloor selection'switch and the actuation coil of the associated sendorder holding relay for blocking actuation of the relay when the car is in transit or at another station, the emergency call means being directly operably connected with the actuation circuit of the send order holding relay for the emergency call station independently of position or motion of the car.

20. A control system for a vertical lift apparatus of the type including a hatchway extending between an uppermost terminal station and a lowermost terminal station with at least one intermediate station and with a car guided in said hatchway and motor propelled for upward

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