CA1052484A - Elevator stop control arrangement - Google Patents

Abstract

ELEVATOR STOP CONTROL ARRANGEMENT

Abstract:
Apparatus for the control system of an elevator in which the arrival of the elevator at the rated speed stopping distance from a landing at which it is to stop while traveling at less than the rated speed delays the initiation of a stopping operation for that landing until the car attains an optimum speed.

Description

~S~ 4 This invention relates to elevator control systems.
More particularly, it concerns an arrangement for generating stopping signals to initiate stopping operations for an elevator car.
S In order to permit elevator cars to make trips be-tween adjacent landings in systems in which the stopping dis-tance from rated speed is less than the typical distance be-tween such adjacent landings it is common practice to employ -landing selector apparatus. Part of this apparatus moves in synchronism with the car and produces a stopping signal for a landing, if it is desired to stop there, upon the arrival of the car at its rated speed stopping distance from the land-ing. Alternatively, in place of the landing selector appara- ~
tus in such systems a separate switch for each direction of ~-travel to each landing is located in the hoistway for actua-tion by the car upon its arrival at the rated speed stopping -distance from the respective landing in order to enable the ge~eration of a stopping signal for that landing.
In some installations the rated speed is such as to require a stopping distance greater than one half the ~ypical distance between adjacent landings but still less than this typical distance. In these, additional equipment common to all landings is sometimes employed with the foregoing arrange- `
ments to indicate whether or not a car is going to make a trip between adjacent landings. This equipment is needed to pro-vide acceptable operations on such trips. Upon starting from any landing the car arrives at the rated speed stopping dis-tance from the next landing in the direction of travel very shortly after acceleration has begun. Without the additional e~uipment referred to herein, the stopping signal on a trip between adjacent landings would be generated at the time of that arrival and would preven~ the car from accelerating to a satisfactory speed on such a trip. Consequently, the time expanded on such trips would be extensive and unacceptable.
Even the operation provided by such additional

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equipment has not been totally acceptable, however. It typically limits the car to a speed well below the maximum it could attain on such trips consistent with passenger com-fort. This is particularly so in installations in which the distance between each pair of adjacent landings is not the same. To overcome such objectionable operations some instal-lations have also been provided with individual equipment for each direc-tion in which a car can approach each landing on a trip from an adjacent landing. This equipment is utilized to indicate the arrival of the car at that distance from the re-spective landing which has been determined to be the suitable distance at which to generate a stopping signal on a trip ' from the adjacent landing in the appropriate direction. Ex-cessive expenditures can be incurred in providing such in-dividual equipment, however, not only because of the cost of the equipment but also as a result of the extra expense in-volved in installing it and adjusting it to operate properly.
It is an object of this invention to improve the operation of elevator cars.
It is ano''~her object of this invention to provide a simple control arrangement for elevator cars which travel -at rated speeds requiring a stopping distance more than half but less than the whole typical distance between landings. ~' The arrangement enables such car~ to accelerate to optimum speeds consistent with passenger comfort on trips between ad- `
jacent landings regardless of variations in the distances be-tween such landings. ~' One of the features of the invention is that it en~
ables a car to continue to increase its speed after it reaches the rated speed stopping distance'from a landing at which it is going to stop if it is traveling at less than rated speed when it reaches that point. ~ ' Another feature of the invention is that it utilizes the indication of the arrival of the car at its rated speed stopping distance from any landing to control the generation '

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of stopping signals for that landing whether or not the car is traveling at rated speed upon its arrival at that location.
In carrying out the invention a delay means includ-ing a prescribed speed signal generator is employed which re-sponds to the car traveling at less than its rated speed whenit arrives at the rated speed stopping distance from a landing.
This generator thereupon operates to produce a signal signify-ing the maximum speed the car can attain and still stop in a satisfactory manner at that landing. This signal is then com-pared with a signal signifying the instantaneous speed of the car produced by a tachometer generator driven by the hoisting -~
motor. The delay means operates to delay the generation of a stopping signal in response to the registration of a call for the landing until the magnitude of the signal from the tacho-meter generator equals that of the signal from the prescribed speed signal generator.
One of the advantages of the invention is that it enables the car to start from a landing and stop for a call for the immediately succeeding landing notwithstanding the call is ~ot in registration for the succeeding landing when the car is located at rated speed stopping distance from it.
Such a stop is possible as long as the call is registered before the car speed exceeds the ma~imum speed signified ~y `~
the output signal of the prescribed speed signal generator.
~5 In accordance with the invention there is provided ;
apparatus for the control system of an elevator car which ac-celerates in accordance with a prescribed pattern, said ap-paratus generating signals to initiate stopping sequences for the car and including, a position responsive device operating in response to the location of the car at that predetermined distance from a landing at which a stoppiny operation is to be initiated when the car is traveling at its rated spe d in order for it to decelera~te in a desired manner to a stop at said landing; call registeriny units operable to ragister calls for service or said landing; a stopping switch oper-

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~L~5:2~84 acting in response to the operation of said position re-sponsive device and to the existence of the registration of a call for said landing whe~ said car i5 travelling at said rated speed to initiate a stopping operation to decelerate said car in said desired manner to a stop at said landing; said apparatus being characterized by delay equipment opera~ing on those trips in which the car is traveling at less than its rated speed when it arrives at said predetermined distance from said landing sensing the arrival of the car at said predetermined distance from said landing while tr~veling at less than said rated speed and operating to enable said stopping switch to initiats a stopping switch to initiate a stopping operation in response to a call for said landing registered after said car approaches closer to said landing than said predetermined distance.
Other objects, features and advantages of the inven~
tion will be apparent from the foregoing and from the follow- ;ing description when considered in conjunction with the appen-ded claims and the accompanying drawing, in which Figure T is a simplified representation of parts of an elevator installation including an elevator car and a por- ;
tion of its hoistway together with other associated equipment;
Figures II and III taken toyether constitute a sim- !
plified wiring diagram of the control circuits for an elevator;
Figure IV is a simplified wiring diagram of part of the presently preferred stopping signal generating circuits;
Figure V is a graph of an approximation of the curve of velocity plotted against time for a typical elevator car operation; and Figure VI is a curve of the relationship of veloci~
ties utilized in practicing this invention.
The following is a list of the names of the electro-magnetic switches shown in the drawing. Listed adjacent these names are reference characters utilized throughout the speci-fication to identify the switches and in the drawing to iden-tify ths actuating coils of the respective switches.
lC, 2C, 3C, TC CAR CALL REGISTRATION SWITCE~ES*
lU, 2U, 2D, 3U, 3D, TD ~ALL CALL REGISTRATION SWIl~ES*
D DOWN DIRECTION SWITC~I

~OSZ4B4 EV :E~VEN F LOOR SWI TCH
. ~ EVD DEL~YED EVEN FLOOR SWITC3 lFL, 2FL, 3~L, TFL LANDING SW~TC~ES*
LVA I,EVELING APPROAC~ SWITCH
Ml' HALL TIME SWITCH
OD ODD FI,OO~ SWITCH

S START STUP CONTROL SWITC~*
SD DELAYED SLOWDOW~ SWITCH
Sp STOPPING DISTA~CE SWITCH
UP DIRECTION SWIl'OEI .; ~ ~.
Vm MAXIMUM VELOCIq~Y SWI'rCH
XD AUXILIARY DOW~ DIRECTIO~ SWITCH
XU AI~XILIARY UP DIRECTION SWITCEI
Z ZO~E SWITCH* -~ .
Switches designated with an asterisk (*) are of the latchir.g type; their reset coils are distingui~hed from their actuating coils in the drawing by adding the suffix l~tter (r) to the previously listed reference characters used to identify their respective actuating co`ils. The e same reference char-acters bearing the suffix letter (r) are also employed in the specification to identify the reset coil~ ~f the respective swit~hes ... . .. .
Prefix numerals included in certain of the above and other reference character~ employed in this application lndicate the individual landing~ with which the equipment ~:
identified by tho~e reference character~ i~ asYociated. T~e prefix letter T indicate~ that the equipment with w~ich it i9 u~ed i8 as~ociated with the top landing.
Electromechanical ~witches shown on ~he drawing are designated a~ follow~:
EM I EVEN INDUCTOR SWITCH
LVD D~W~ hEVELI~G 9WITC~ ::
6~
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.
LW UP LEVE~ING SWITCH
O ODD INDUCTOR SWITCH
~ume~cal suffixes are appended to the above re~er-ence characters-for the electromagnetic and electromechanical switches in both the specification and drawins to identify the contacts of the respective switches.
Electromagnetic switches are sh~wn in the deener-gized and reset states while the electromechanical switches are illustrated in the unoperated state -Resistors, c~pacitators and rectifiers are identi~
fied in the drawing by the reference characters R, C, and CR
respectively. Appropriate suffix numeral~ are appended to these characters to differentiate one element from another.
It is to be understood that to facilitate the dis-closure of the invention it is illustrated in a system which is much simpler than would be found in a commercial instal- ~i lation.
Referring to Figure I of the drawing, elevator car CA and counter~eight CW ars suspended in typical ~ashion from hoist ropes HR which pass over sheave TS to be driven thereby when hoist motor M rotates the sheave. Tachometer TACH com-prises a speed responsive means and is driven by motor M to provide an output voltage signal along line VTAcH proportion-al to car speed. Odd and even inductor switche~ ~ and EM are mounted on the exterior of the car, so that each coacts with th0 appropriate odd and even groups of vertically disposed floor vanes lFVD, 2FVU, 2FVD, 3F W, 3FVD and TFVU (Fig. I) to operate contact~ 01 and EMl, respectively (Fig. III). To-gether these switches and vanes comprise the position respon-sive means of the apparatus disclosed herein.
A different 100r vane is provided for each direc- -tion in which the car can approach each landing. The vanes associated with the respective up and down direction~ are identified hy the ~uffix letter U and D appended to their re~pective reference characters.

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Each ~loor vane includes bot~ inner and outer active se~tions ~epara~ed by an inactive section. The associated inductor switch EM or 0 is activated and released upon enter-ing and leaving ~he zone of influence of each active section of each o~ its associated vanes. Each vane is so located in the hois~way with respect to its associa~ed landing ~hat its respective inductor switch leaves the zone of influence of it-q outer active section lD0, 2UO, 2DO, e~c. upon elevator car CA
arriving at rated 6peed stopping distance from ~he landing in lts approach tc it in the direction associated with the re- ~;
spective floor vane. Entry into each outer active sec~io~
occurs suficiently in advance of the rated ~peed ~topping distance to perm;t the operation of the circuitry o~ landing switches, lFL, 2FL etc. (Fig. III) in response to the activa- -tion of the respective inductor switches EM and o to produce the proper indications of the location of elevator car CA.
Inner active section lDI, 2UI, 2DI, etc. are lo-cated in relation to their respective landings to provide a ~;
proper transition from main operation to leveling operation during deceleration. The latter operation i9 well known and in the disclosed embodimenk is pro~ided by the cooperation of up and down leveling ~witches L W and LVD mounted on car CA
with the associated levbling cams lLCU, lLCD, 2LCU, 2LCD e$c. ~s-which are appropriately mounted in the hoistway.
Up and down hall call buttons lSU, 2SU, 2SD, etc.
and car cal~ buttons lSC, 2SC etc. are illu~trated both in Figure I and Figure II. These operate upon being pressed by a passenger and.complete circuits from line El+ to line HLl through the set or actuating coil~ of the respective hall and car call switches to actuate those switches.
Amplifier Al shown in Figure IV comprises a portion of the delay means shown in that figure and i~ an operational amplifiér arranged with capacitor C4 to form an integrator.
~hi8 stores the magnitude~ of the 3ignal~ applied to it along line VT~cH ~rom tachometer TACH (Figure I). The ~tored ;

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~1~5Z484 signals are applied along line Vi to operational amplifier A2; arranged as an inverter. The signals from amplifier A2 are applied along line -Vi to operational amplifier A3.
This latter amplifier is arranged as a summing amplifier to operate as a prescribed speed signal generator and generate prescribed speed signals.
In response to both the input signals applied to it along line -Vi and the bias signals applied to it along line E2+ or E2- through rheostat R10, amplifier A3 produces out-put signals along line V2. These output signals are compared with the signals along line VTAcH from tachometer generator TACH by comparator COMl. The latter produces an output volt-age which energizes the coil of delayed slowdown switch SD
whenever the magnitude of its input signal along line V2 is greater than the magnitude of its input signal along line VTAcH
and operates to deenergize the coil when the magnitude of its two input signals are equal. The signals along line VTAcH
are also applied to comparator COM2 to cause it to produce a voltage to energize ~he coil of maximum velocity switch Vm whenever the magnitude of the signal along line VTAc~ equals -~
that of the signal along line Vl which is scaled to represent the rated speed.
The curve of velocity versus time of Figure V re-presents an approximation of speed as a function of time for a trip between adjacent landings by an elevator car with a duty rating for which this invention is~appropriate. Missing from the curve are periods at the beginning and end of the c~cle which would represent an increasing acceleration during the former period and a decreasing deceleration during the latter. Although the curve is an approximation it is suf-ficiently accurate to serve the purpose for which it is used.
Gn a trip on which the car is not traveling at rated speed when it arrives at the rated speed skopping distance from a landing the curve can be used to determine the relationship between the car's speed at that distance and the maximum _g_ ~SZ484 speed the car can attain before a stopping operation is to be initiated in order for it to stop at that landing in a desired manner on that trip.
In order to understand how this relationship is de-termined assume that the car accelerates and decelerates atconstant rates of 4 feet per second per second and transfers from acceleration to deceleration at a constant rate of change of 8 feet per second per second per second. Also assume that under these conditions the stopping distance for the car travel-ing at rated speed is signified by the term STD. Since thecurve of Figure V represents a typical less than rated speed operation then the area under the curve represents the total distance St traveled during the trip. Also since the time t represents the time at which the car arrives at the rated speed stopping distance from the landing at which it is to stop at time tf the area under the curve from time t to time tf equals this stopping distance STD. The stopping distance STD plus the distance traveled from time to to time t repre- -sented by the reference character S also equals the total , -distance St traveled during the trip. Consequently, the total distance St can be defined by the equation:
t p (1) or since S = 1~2V t equation (1) may be written as St = 1/2V t ~ STD ~
It should be evident, from observation, that the total dis-tance St can also be defined by the equation:
t 1/2Vata + Sk -~ Sc + Ss (3) Setting equation (2) equal to equation (3) 1/2Vptp ~ STD = 1/2Vata + Sk + S~ ~ Ss (4) Since the curve is symetrical about time tx and the magnitude of the velocity V is equal to the magnitude of the velocity ~, .
Va, Ss = 1/2Vata, therefore equation (4) can be rewritten:
1/2Vptp + SqlD a L/2Vata + Sk ~ SC ~ 1/2Vata ( 5 ) With the forementioned acceleration?,~kdeceleration and rates of change thereof it can be shown by straightforward mathe-;', . ' .

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matics that:
~k ~ 2/3 o~ a foot (6 and S = V t ~7) c a c where t = 1 second One second i5 th~ ~ime it take3 to go rom velocity Va and an acceleration of 4 f~et per second per second to ~elocity Va and a deceleration of 4 feet per second per ~econd at a rate of change of 8 feet per secon~ per second per seco~d ~herefore Sc = Va(~) a (8) Equations 5, 6, and 8 can now be combin~d to gi~e:
1/2Vptp + STD = ~ata + 2/3 + Va (9) :`
Moreover, since time is egual to veloci~y divi~ed b~ aa~eler- .
ation and the acce~eration is constant at 4fps d~ing ~imes t and t equation (9) can be rewritten as P a 2 2 1/8 Vp STD = 1/4V + 2/3 -~ V
or V ~ 2V ~ 8V - 8STD ~ 5 1/3 (10) :
. ~quation 10 defines the relationship between the velocity of the car at its stopping distance point from a landing at which it is to stop and the maximum velocity the ~:
car can attain on that trip before a stopping operation is to be initiated if the car is to operate i~ accordance with the curve of Figure V.
Where the stopping distance point is located eight feet from ~he landing as is the herei~ de~cribed embodiment, equation (10) can ~e rewritten Vp = 2Va2 ~ 8Va - 58 2/3 (~lt or transpo~ing and solving for V
r----~r----------~a Va ~ -2~ ~1/2Vp ~ 33 1/3 ~12) While those skilled in the art will realize that circuitry could readily be built to implement the solution of the positive portion of equation (12) it has been ~ound satis-factory in the range of speeds o inte~est, namely up to ap-proximately 400 fpm, to utilize a st~aight line approximation of equation (12) w~ich is ~h~l on Figure VI and defined by the equation:

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Va = 0.2Vp ~ 4.1 fps (13) Figure IV illustrates the circuitry utilized to implement the solution of equation (13).
To more fully appreciate the invention and the man-ner in which the preferred embodiment operates, assume that elevator car CA is located at the first landing. In these circumstances, first landing switch lFL (coils Fig. III) is in the set condition, its set coil having been the last o its two coils to be energized. Zone switch Z (coils FigO III), start-stop control switch S (coils Fig. II), landing switches 2FL, 3FI., TFL (coils Fig. III) and call registration switches lU, lC, 2U, etc. (coils Fig. II) are in the reset state, their reset coils being the last of their two coils to be energized. The remaining switches are in their deenergized ~ -states.
Assume a hall call is registered by an intending '~ ' passenger pressing top hall call button TSD (Fig. II) causing the energization of the upper or set coil of top hall call registration switch TD through the completed circuit from :. .
line El~ to line HLl. As a result contacts TD3 (Fig. II) close and power is applied to the coil of auxiliary up direc-tion switch XU (coil Fig. II) through closed contacts ~T4, ~D3, rectifier CRl, and contacts D2 and XD6 causing auxiliary up direction switch XU to transfer to its actuated state closing contacts XUl (Fig. II) and completing a circuit to the set coil of start-stop control switch S (coil Fig. II) through ;~
normally closed contacts NT2. As a result switch S transers to its set condition closing contacts Sl in the circuit of the coil of up direction switch U (coil Fig. II) causing the ;;
energization of the coil by way of closed contacts Sl, XU5, D2 and XD6. This actuates up direction switch U which in con-junction with start-stop control switch S may be utilized to start and operate ele~ator car CA in the up direction in any well known manner.
As an exampl~ of the manner in which up direction . . . -.

~5i24~34 switch U and start stop control switch S may ~e utilized to s$art elevator car CA, assume car CA is installed in a system in which it is driven ~y a d.c. hoisting motor arranged in a Ward Leonard system with a self-excited d.c. generator. As is well known, switches S and U may be employed in such an installation to actuate accelerating switches the operation of which control the amount of current that flows in the gen-erator's shunt field winding to start and accelerate the car.
Alternatively, elevator car CA may be installed in a system in which it is driven by an a.c. motor of a well known control system of the type in which switches S and U may be employed to apply a step input voltage to the input of a pattern gen-erator which will start and accelerate the car.
Energizing start-stop control switch S also acti-vates the delayed slowdown means (Figure IV) of this inven-tion. Contacts S3 (Figure IV) close in series with closed contacts Vm2 to connect the output of comparator COMl to the coil of delayed slowdown switch SD (coil Figure IV). Com-parator COMl, a two input differential amplifier, as mentioned earlier, compares the magnitude of the output signal from summing amplifier A3 along line V2, with the magnitude of the signal along line VTACH- The signal along line V2 generated as a result of the bias signal along line E2- applied through closed contacts U13 and input rheostat R10 to summing ampli- ;
fier A3 is greater in magnitude than the signal on line VTAcH
when the car starts its movement in the up direction. Con-sequently, comparator COMl produces an output signal which energizes the coil of delayed slowdown switch SD (Figure IV) through closed contacts S3 and Vm2. Delayed slowdown switch SD thereupon transfers to its actuated state and closes con-tacts SDl. (Figure II~
Closed contacts SDl, EVD4 and ODD4 connect line El-~to the coil of stopping distance switch S (coil Figure II) , ' ' ' ~(~5;~:~8~
energiæiny ~he coil to ac~uats the switch. ~hen stopping distance switch S transfers to its energized state it closes contacts S 1 (Figure IV) to connect the signal on line VTAcH
from tac}lometer generator TACH to the input resistor R5 of operational amplifier Al. This stores t~e ou~put voltage along line VTAcH on line Vi for future use when contac~s Spl open. Operational amplifier A2, connected as a s~andard in-verter, applies the inverse of the signal on line Vi to line V.. This inverted signal is connected to the second input .
resistor R8 of summing amplifier A3 and is added with the bias .
signal connected through rheostat R10 to maintain the magni-tude of the signal along line V2 greater than that along line VTAcH and consequently maintain delayed slowdown switch ~D ~.
actuated. .
Continued acceleration and mov~ment of car CA in the up direction brings even floor inductor switch EM into the zone of influence o~ outer active section 2UO of ~ven floor ~-vane 2FW causing contac~s EMl(Figure III) to close. This .
completes a circuit to the set coil of second landing switch .-2FL (coils Figure I~I) through contacts Ell XU9 and lFL5. :
As a rPsult second lar.ding switch 2FL operates to its set eondition signifying that the car i~ approaching the ~econd landing. Simultaneously, a circuit is also completed to the coil of even floor switch EV (coil Figure III) through closed :~
contacts E1 and Z6. Upon this switch transferring to its aetuated state contacts EV5 close to energize the set eoil of zone switeh æ (eoil Figure III) through those elosed contacts and contacts E1. Operating zone switch æ to its set eondition closes contacts Z3 and completes the eircuit to reset coil of first landing switch lFL (coils Figure III) through contacts EMl, Z3, lFL3. ~he operation of first landing switch lFL to its reset eondition together with the pre~iously described operation of second landing switch 2FL to its set eondition eompletes the transfer of the indieaked location of the car from the fir~t landing to the seeond.
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Tha actuation of even floor switch EV al~o closes contacts EVl to complete a circuit to the coil o~ delayed even floor switch EVD (coil Figure II), through those contacts and closed contacts SDl o~ actuated delayed slowdown sw~tch SD. As a re~ul~, delayed even floor ~witch EVD is actuated to enable car CA, as will be explained, to continue to be able to stop a~ the second landing in response to a second landing call notwithstanding the cal~ may be registexed ~fter the car has traveled beyond the point identifying the rated :~
speed stoppiny distance from the second landing.
The actuation of delayed even floor switch EVD opens contacts EVD4 ~igure II) to interrupt thP circuit of the coi~
of stopping distancQ switch S . This ca~ses the switch to separate its contacts S 1 (Figure IV) disconneating line VTAc~I from input resistor R5 of amplifier ~1. When this occurs, the output voltage of tachomet,er l'AC~ (~igure I) at that in~
stant i~ ~tored by capacitor C4 (Figure IV). This voltage i.s applied along line Vi and represent~ the speed at which the ;:
car is traveling a~ that instant in its mo~eme~t through the zone of influence of outer active section 2UO (Figure I) o even floor vane 2F W . By design th~se outer zones are chosen to be only large enough to enable a car ~aveling at rated speed to maintain the even and odd floor switches EV and OD ::
in their actuated ~tates for a sufficient time to permit the reset of start-stop control switch S and a respective car and/ ~:
or hall call registration switch lU, lC, 2U, 2C, 2D, et~. As will be understood the length o~ the~e zones, accordingly, .is relatively small. Con~equently, even though the car is not now traveling at its rated speed, ~o~ present purposes, the . speed at which it is traveling when contacts Spl open can be considered the ~peed at the rated speed stopping distance ;
from the ~econd landing which has been pxeviously identifi~d a~ the point at which even inductor EM exits from the zone o `:
influence o outer active section 2uo . The ~pead at the rated ~peed stopping di~tance as earlier explained an con~ection ::~
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with equations (1) through (~3) is iden~iied by the reference character Yp and is utilized in determining the maximum speed, Va, the car can attain on a less than rated spsed trip before it must begin its stopping operation. In accordance with the present invention the voltage stored on capacitor C4 and ap-pli~d to line Vi when contacts Spl open i~ employed as the speed Vp at the rated speed stopping distance in determining the maximum ~peed the car can attain.
After inversion by amplifier A2, the voltage applied `
along line Vi is transmitted by line -Vi to input resistor R8 of ampli~iex A3~ Also transmitted to this amp~ifier through input resistor R10 for summation with the voltaga along line V is the bias voltage applied along line E2-. The magnitude o~ this bias voltage in relationship with the magnitude of the voltage along line -Vi together with the characteristics of ampli~ier A3 and the values of resistor R8 and R10 are such as to cause the voltage produced on line V2 to be equal to two-tenths the voltage on line Vi plus a voltage equivalent to 4.1 feet per second. As a consequence, this equipment im-plements the solution of equation (13) namely that Va - .2Vp ~ 4.1 and accordingly the voltage applied along line V2 represents the maximum speed the car can attain before it must begin its stopping operation if it is to stop satisfactorily at the second landing on this trip. 5ince no call is in registra-tion for the second landing at this time, the voltage along line V2 i8 maintained ~or ukuxe use if needed.
Further motion of the car removes inductor switch EM
from the zone of influence of outer active section 2UO of even floor ~ane 2FVU causing contacts EMl to open. This deen-ergizes the coil of even floor switch FV by interrupting its circuit to line El~, thereby releasing the switch. Ihis, as mentioned earlier, signi~ies that car CA is located at that point identi~ying the rated ~peed stopping distance from the second landing.

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To more fully understand how the invention enables tha car to stop for a call registered at the second landing even though it is registered after the car is closer than the rated speed stopping distance from the landing, as~ume S that shortly after even floor switch EV is released, a pros-pective passenger presses the second landing up hall call button 2SU (Figure II). This causes the registration of a second landing up hall call by energizing the set coil of the up hall call registration switch 2U (coil Figure II) through l~ the completed circuit from line El+ to HLl, actuating the switch to its set state.
Th2 operation of second hall call registration switch 2U to its set state closes contacts 2Ul. These contacts are in series with reset coil Sr of start-stop control switch S, closed contacts EVD3, 2FLl and XD~ and reset coil 2Ur (Figure II) of the hall call registration switch 2U. Thus the actuation of second hall call switch 2U to its set state, closes of its own contacts 2Ul, immediately energizing its reset coil 2Ur and transferring itself to its reset state.
2~ Simultaneously, however, reset coil Sr of start stop control switch S (coil Figure II) is energized causing that switch also to assume its reset state.
As is well known, the transfer of start-stop control switch S to its reset condition when the car is traveling at rated spesd is utilized to initiate the deceleration o~ the car. In the forementioned d.c. motor drive system of the `-self-sxcited Ward-Leonard type it is most commonly employed -to release the highest order acceieration switcho The lower ~;
order ones bein~ released as the car arrives at predetermined ;~
distances from the landing at which it is stopping. In the a. c. motor drive system of the type previously mentioned it is employed to remove the step input voltage which as was previously discussed would be applied to a pattern generator to start and accelerate the car and to sub-stitute therefor a leveling speed voltage to cause the car ~. '',' ~ .
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.to decelerate to its levaling speed.
' Notwithstanding start-stop con~rol switch S has been transferred to itS reset condition, however, the continued actuatioll of delayed slowdown switch SD can be ~mployed in any suitable manner by those skilled in the art to d~lay the initiation of the deceleration of the car~ Delayed slowdown switch SD is maintained actuated until tha speed of car CA as signified by the signal along line VTAcM equals the prescribed speed signal generated by ~he prescribed speed si.gnal generator 1~ comprising amplifier A3 and applied along line V2. At that.
time the two signals applied to comparato~ COMl are equal and, as stated previously, under such ci~cumstances the ~oil of switch SD is deenergized and the switch xe~eases t~ its un-actuated state 15The release of delayed slowdown switch SD in con~
junction with the previous release o start-~top control witch S can be employed to initiate the deceleration of the car in any suitable manner similar to the manner in which khe release of switch 5 when the car i.s traveling at raked speed inikiates deceleration. Further slowdown of the car to its leveling speed can also be provided in a manner similar to that provided when the car is on a t~ip on whic~h it ha~ at- `~
tained rated speed.
Upon approaching the zone o in~luence of inner active section 2UI (Figure I) of aven 1~or vane 2F W , even ~loor inductor switch EM is again actuated and closes contacts EMl (Figure III). Thi~ completes a circuit to the coil o~
leveling approach switch hVA through the additi.onally closed contacts Zl, Ull, OD2, EV2 and S6 and actuate~ t~e ~witch to open its contacts LVAl.
Xn the meantime before these aontacts open, up leveling switch LW engages second landing up leveling cam 2LCU (Figure I~ cau~ing it~ contacts to close. This maintains up direction switch U actuated through the circuit including closed contact~ LW (Figure II~ when con~acts LVAl open. Thi9 .
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~L~52~

circui~ is maintained to enable the car to operate at lavel-ing spee~ until it arrives at the landing and up leveling swi.tch LW is disengaged from up leveling cam 2LCU.
Maximum velocity switch Vm (coil Figu.re IV) is pro-vided to prevent delayed stopping switch ~ from interferring with the initiation of the deceleration operation in response to the release of start-stop control switch S on trips on which the car attains its rated speed. Upon that occurrence the magnitude of the signal along line VTAcH equals the magni-tude of the signal along line Vl and comparator COM2 producesa voltage ~uficient to energize the coil of maxi.mum velocity switch Vm. As a consequence the switch operates to its actu-atad condi.tion and openq its contacts Vm2 (Figure IV) in the coi.l circuit of delayed slowdown sw.itch SD. Once actuated maximum velocity switch Vm is maintained in that condition for the remainder of a trip ~y the current applied to its coil ~rom the supply applied along line E3 through contacts Vml and U7 or D7.
Various modifications to the oregoing arrangement will be evident to those skilled in the art and for that reason it is intended that the arrangement be considered il~
lustrative onl~ and not limiting in any sense. ~ ;~

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Claims (5)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Apparatus for the control system of an elevator car which accelerates in accordance with a prescribed pattern, said apparatus generating signals to initiate stopping se-quences for the car and including, a position responsive de-vice operating in response to the location of the car at that predetermined distance from a landing at which a stopping operation is to be initiated when the car is traveling at its rated speed in order for it to decelerate in a desired manner to a stop at said landing; call registering units operable to register calls for service for said landing; a stopping switch operating in response to the operation of said position re-sponsive device and to the existence of the registration of a a call for said landing when said car is traveling at said rated speed to initiate a stopping operation to decelerate said car in said desired manner to stop at said landing; said apparatus being characterized by delay equipment operating on those trips in which the car is traveling at less than its rated speed when it arrives at said predetermined distance from said landing sensing the arrival of the car at said predetermined distance from said landing while traveling at less than said rated speed and operating to enable said stopping switch to initiate a stopping switch to initiate a stopping operation in response to a call for said landing registered after said car approaches closer to said landing than said predetermined distance.

2. Apparatus according to claim 1, characterized in that said delay equipment includes a speed responsive device operating in response to the instantaneous speed of said car to produce a signal representative thereof, a prescribed speed signal generator operating in response to the arrival of said car at said predetermined distance from said landing and generating a prescribed speed signal at said predetermined distance which is a function of the instantaneous speed of the car upon said arrival, and a comparator circuit producing a signal for delaying the initiation of a stopping operation on said trip until a predetermined relationship exists between said instantaneous speed signal and said prescribed speed signal.

3. Apparatus according to claim 2, characterized in that said comparator circuit is rendered ineffective to produce a signal for delaying the initiation of a stopping operation on any trip upon the car attaining its rated speed.

4. Apparatus according to claim 3, characterized in that said delay equipment includes signal storage means receiving and storing the instantaneous speed signal pro-duced at said predetermined distance; a bias signal generator operative to produce a bias signal and a summing amplifier operative to sum the stored instantaneous speed signal and said bias signal to produce said prescribed speed signal.

5. Apparatus according to any one of claims 1 to 3 characterized in that said prescribed speed on each particular trip on which said car does not attain its rated speed is that speed which is determined in accordance with said prescribed pattern to be the greatest it can attain on that trip before initiating its stopping sequence if it is to decelerate in said desired manner to a stop at said landing.