US1689583A - Electrical control system operable automatically to level elevators with landings - Google Patents

Description

ELECTRICAL CONTROL SYSTEM OPERABLE AUTOMATICALLY E. L. GALE TO LEVEL ELEVATORS WITH LANDINGS Filed July 15, 1925 2 Sheets-Sheet l Get. 30, 1928. 1,689,583

' E. L. GALE ELECTRICAL CONTROL SYSTEM OPERABLE AUTOMATICALLY TO LEVEL ELEVATORS WITH LANDINGS Filed July 15, 1925 2 Sheets-Sheet 2 I 5 r I LE1 E 5? JfL QALE S fM fz? fiatented- Oct. 30, 1928.

. v UNITED srArEs PATENT; OFFICE.

mesa.- .n earn,

or YoNxEns', NEW .YORK, nssrenoit T GURNEY ELEVATOR com- I'ANY, INCL, A: COBPORATION OF IPENNSYLVANIA.

:aLEc'rnrcA common sy'srnn ornmmnn AUTOMATICALLY T0 LEVEL ELEVATORS wrrn LANDINGS. Y

Application-flied July 13, 1925. serial No. 43,080.

come toxa stop either above for below the landing, and this fault is due to the automatic stopping apparatus now in common. use wherein the adjustment to control the stopping operation car only with average load to a substantially,

level stop by 'coasting. Hence'both time and car over-runs the landing jand this is so even with the use of automatwF-levelmg devices now in common use because' of premature slowing down and very slow speed operation of the car through the leveling zone. 1 Hence, one of the ob'ects of the present invention is to save time and power by the provision of axlfl d. controlled stopping switch which variesa'ut'omatically the point at which the hoisting operation is discontinued so that the varying coasts of the car due to' varying load conditions will bring the car I to' a gjgravit stop sub tantially level with the landin .iwithout lia ility of Thus t e load switch will, for heavy load descending qand-light load ascending, automaticall discontinue the hoistingoperation with respect'to a pre-determinedlanding, and as s to point of time, sooner, than for a light load descending -and a heavy load ascending, thereby taking is such that the maximum coa'st will bring the is permanent and brings the over-running."

full advantage of those load conditions which causdthe car to coast the ma imum distance findthe timingoperation.

car to a gravity stop substantially level with the landing without liability of over-run.

wardly, or rather to raise its counterweight so that thesame coasting condition is present with a light load descending as with a heavy load ascending; neither will coast as far as will a light load ascending or a heavy load descendin Since the car in coming to a gravity stop, moves at a uniformly decreasing-rate, such stop isan ideal method and rerults in asubstantial saving in time as compared with those leveling systems having a premature slow-down and a continued constant slow speed ,movement of the carthrough a leveling operation, the main purpose of which is toiminimize he possibility of'ove'r-run.

*heavy load ascending and light load descend- ,ing, continue the hoisting operation for a I A power s wasted, more particularly when the i longer period of time than for a heavy load descending and alight load ascending, therebringing the car nearer to the landing and discontinuing the hoisting operation, so that under these load conditions which give rise to what maybe termed theminimum coast,

such coast will bring the car to a gravity stop without liability of over-run, such stop on the other hand the load switch will for bringing the car substantially level with the landing.

In the operation of elevators it will be observed that. heavy load descending and light load ascendingare the conditions which give rise to maximumcoast of the car and contribute, more than any other factor to the over-run movement of the car, and since the timing operation as efiected by the load stopping. switch efiects a gravity stop without liability of over-run, a very slow speed apparatus need not be empl yed and, only a single hoisting motor as now commonly used for high speed elevators can be employed,

which motor may operate the car at about a one hundred foot rate per minute, as slow' speed.

The load controlled switch in its present embodiment, controls the car sothat it s coast brings itto a gravity stop within the bounds of what will be termed an exact leveling zone, this zone being necessarily very short and extending say only a few inches either side of a landing. When the car is in this zone, the hoisting operation is again continued under the control of leveling switches, and

since the operation to level the car is of such short duration, the motor will not attain any appreciable speed. Furthermore, the leveling switches will operate automatically to maintain the car level with the landing during loading and unloading, under which con.-

ditions the car may tend to move from the landing due to change in length of the hoisting cables.

Other objects of the invention will appear hereinafter, the novel combinations of e1eautomatic'rstopping switch; Fig. 2, illustrates windings 6 and 7, is controlled by reversing.

a load controlled stop an electrical control system for elevators embodying. a load controlled automatic stoppin switch of modified construction adapted or use with both A. C. and DC. systems; Figs. 3, 4, and 5 illustrate different relative positions which the load stopping switch assumes for different load conditions, and Fig. 6, illustrates a load controlled stopping switch of modified construction. Referring now to Fi 1, the elements comprise an elevatorc-ar in" or gearing y a hoisting motor M prov1 ed with a usual electro-mechanical brake B m which the brake is applied by a spring 1,

and is released by a brake magnet 2. A shunt field winding for the motor is designated 3, a starting resistance 4, and an accelerating magnet automatically to control the startlng resistance is designated 5. Reversing switches for the motor M R", and a feed circuit for reversing switch rovided with wind 9 respective y, and also'by the ing1 switch designated L. S., to ether in t eelectro-magnetic switches and E. A car" switch-F in the present mstance'is of a type adapted for manual control by being provided with a usual-hand lever 1 and which is also ada ted for automatic actuation by being provided .Wltll a pair of bell-crank levers ll each car- 'switch rela s T and T jings 8 an rying a roller 13, said leversbeing connected by a pairof rods 13, fulcrumed at 14 which .is' eccentricto the center pivotal support of said on switch. The-rollers 13are adapted.

to -co-act with apair of leveling cams 15 and 16 positioned in the-elevator hatchway, there S er1al-llo..635,764, g

I 'Commg now tothe loadcontrolled stopbeing a pair of cams for each floor, only one floor being illustrated herein. This is more fully described inm cofiending application,

pril 30,1923.

ping switch L. S., it as a whole is carried on the elevator-car, and comprises an arm 17 whichmay be oper-- ated through an well known system of rop are designated R,

secured to which is a contact'sector 18. A bell-crank lever 19, together with the arm 17, is mounted on a. fixed pivotal support 20,

- current solenoid 24, against the action of a spring 25. In the present instance the de-.

sired operation of the contact sector 18 is obtained by utilizing the starting current of the armature of the hoisting motoras a measure of the load, and to obtain this result the current solenoid 24 1s contained in the armature circuit. A holding-dog 26 is actuated by anelectro-magnet 27 to engage a ratchet 28, and thereby old said contact sector 18 at the highest point to which it has been moved at each operation of the motor from start. A spring 29 releases said dog from the ratchet when the said electro-magnet is de-energized. adapted to actuate the. bell-crank lever 19 in ananti-clock-wise direction and so rock the contact 21 in a path to co act with the contact sector-'18, and the contact 22 will likewise be rocked to co-act with the fixed contact sector 23. A bell-crank lever 31, car ing a roller 32, is operatively connected to't e lever 19, and said lever 31 together with timing cams 33 serve to time the return move ment of the oontacts21 and 22 to normal position by movement of thelever 19 in a clock-wise direction, said timing operation being directly in accordance'with ment of the can.

A complete cycle of operation will now be given; start of the ear 15 initiated by mov- An electro-magnet 30 is the movemg the car switch handle in the desired dicontacts 37 controlled by switch D, now close a feed circuit. for the winding] of the up contacts 36 associated therewith together with reversin switch R. Said feed' circuit may be trace; a as fol 'ows, from plus wire 38, contacts 37, wire 3 ,;relay;contacts 36, through up reversin switch winding 7 and thence to minus line y way of wire 41. The circuit for the relay winding 9 may be traced as follows, from plus wire contact35, to contact 35 byway of the segment 34, wire 42, through relay winding 9, and -thence to the minus line by way ofwire 43. r

The up reversing switch R will now close" and direct current from any suitable source III 'of supply vdesignated plus 'and minus,

tlirough the motor armature in a manner to causethe car to ascend, the main circufis her cams 33, the roller mg well known and need not therefore be traced in detail. The reversing switch closes the brake winding circuit and the brake will thus be released. Assume now that the car has what will be termed its maxiirfum load. Under such load condition, the hoisting motor in starting to move the load in an ascending direction, will draw a relatively heavy current, and the current solenoid 24, being subjected to this relatively heavy current, will rock the contact sector 18 a maximum distance to its limit of movcmeiit as indicated in Fig. 5, against the action of the spring 25, and will be held in this position by the dog 26 actuated by the electro-magnet whose feed circuit 44 is now closed by the reversing switch R fromthe plus main through the two upper right-hand contacts of this reversing switch, wire 44 and solenoid 27, the others terminal of which is connected to the minus main. then the car travels upwardly a few] inches from the landing level through what'- will be termed the leveling zone, and which corresponds to the vertical portion of the 32 engages a rather sharp bevelled portion '46, thereby. imparting a. short rocking movement of the lever 19 to cause the-contact 22 to co-act with the contact sector 23 and by so doing, close a self-holding circuit for thehip relay winding 9, and also close a circuit for the actuating winding 30 which will now rock the lever 19 in an anticlock-wise direction to its limit of travel as indicated in Fig. 5, thereby rocking the conjust traced for the reversing switch winding 4 7 is transferred temporarily from the switch I) to the switch E, the latter switch being under control of the car switch in tofif position, in whiclvposition the segment 34, co-

acts with contacts 64, thereby closing a circuit for the winding 65of-iswitch E,'and the winding 30 of the load stopping switch, said cir cuit being traced as follows, from wire designated plus, wire 66," through winding 65, wire 59, t hrough winding '30, wires 6( )and, 61, contacts .62, andto the minus lineby'way of, the wire The switcl'i 'E will n owoperate and close afeed circuit foii the reversing switclnwinding 7 as follows, from plus wire as, a 47, wi c7; G mer es, anawa- 69 to junction 69 with the wire39; and from" there on heretofore traced.\;;Switch E willalso close contacts 70 which close a cii cuit for,

the winding 7 2ofthe switchD, thereby causing the lattertoopen its. contacts 37 and 58,

"an dby so doing open that point thefeed circuit for -the'reversing switch-winding "7 W as initially traced, and l ab n at that point the circuit initially 'ti'aced for the actuating windingSO. The switch D by closing circuit "for the winding 72 which is maintained closed the relay T, said circuit beits contacts? 3, thereby: closes a.- self-holding ing traced as follows, from plus wire 38,

wire s 47 ndl? 4, through wirfding 72, wire 7 5, contacts 3, wire 76 which forms a-junctio n tacts 21 and 22in paths to co-act withthe con- 776- with the wire 60and from there on astact sectors 18 and 23 respectively. The selfholding circuit for, the up relay windingfi may be tracedas follows,from plus wire 38, wires 47 and 48 to contact 22, sector 23, wires 49, 49, through knife switch 50 in the car, wire 51, back-contacts 52 on down relay T, wire 53, contacts 54, wire 55 forming a jun'c tion at 55' with wire 42, thence through winding 9 to minus line by way of wire 43. circuit for the actuating winding 30 may be traced asfollows, the same as just traced up v to and including the wire 49, thence from a junction 56, wire 57 contacts 58, wire 59, through winding 30, wires60 and 61, through up relay contacts 62, and thence to the minus line by way of wire 63. With the lever 19 now in actuated position. the roller 32 will be in an inoperative position so as to clear the timing cams at floors which the car passes by. Likewise, with the car switch in on position, the rollers 13 are in an inoperative posit-i on so as to clear their respective, leveling cams 15, 16 at floors which the car passes by.

The car now having moved afew inches and thereby closing the self-holding circuit for the up relay winding 9, permits the car switch lever to bereturned to off position, thatis, assuming that a stop is desired at the next adjacent floor, and the carwill continue its travel under automatic control.

heretofore traced for the winding 3'0.

At this point in the operation, we now-have T the reversing switch winding 7-, also the ac-1 tuating winding 30 of the. load controlled stopping switch, under the control of the car switch in its offpositiomand'when the aspending car reaches a,zonewh1ch may be A termed a maximum coasting zone, so called because it is measured by the maximum predetermined distance through whicha maximum loaded car descending will by coasting come to a gravity stop substantially level with. the landing, the car switch will be actuated automatically by the engagement of the roller 13 with the cam 15, to de-energize the windings 65 and 30' by open-circuiting the contacts 64 of the car switch. Thepontrol of the hoisting operation is in this manner transferred to the load controlled stopping'switch exclusively, and at the timewhen the actuating Winding 30 is (lo-energized, the car'will be in such aposition that the roller 32 will engage the highest point designated 77 on the cam 33. The roller 32 in following the inclined face of the cam 33 renders the time factor for the return movement of the contacts 21 and 22, a constant, a spring 7 8 actingto urge said lever 19 to its normal positionas' shown.

' The car is now under the exclusive control of the load contrqlled stopping switch and k the duration of contact between the contact 21 and its co-acting contact sector 18, depends on the degree of rocking movement of said sector as eflected bythe current solenoid 24, and this degree of movement as effected by j utilizing the starting current taken by the armature of the hoisting motoras a means to measure the load, results in a greaterrocking movement of the contact sector for a heavy load ascending and a light load descending,-

than for 3.\ heavy load descending and a light load ascending. It will be observed tha't the automatic transfer ofthe control of the hoisting operation from the centered car switch and switch E, to the load controlled stopping switch exclusively, is always effected at a pre-deterniined fixed point relative to any desired pre-determined landing, said point being that at which the car is in position so that "the roller 32 will. engage the highest point 77 of thecam 33', and by making such provision, the stretch or contraction or rather twist'o-r untwist of the hoisting cables as a factorin causing over-run or under-run is over-come. Take now the heavy load ascending condition as assumed heretofore under v which condition the current solenoid actuates the contact sector the maximum distance. 7 The parts will now assume a relative position sition as timed by the cam 33, rides over the full length of the'sector 18, said contact 21 being rocked sufficiently by .the cam 33 to disengage said sector 18 when the car reaches what may be termed the minimum coasting zone, through which the car by itscoast will bring it substantially level with the landing, or in effect, the zone designated leveling zone The feed circuit as controlled for the Winding of the reversing switch B may be traced as follows, from plus wire 38, wires 47 and 48,wire 78, contact 21 to contact sector 18, wire 79, junction 79 formed with Wire 39,- contacts 36, through reversing switch winding 7, and thence to the minus line by way of wire 41. The self-holding circuit for the winding 9 of the relay contact 22, when the roller 32 rides down the qsharp bevel 46, and the roller 32 will now engage the vertical face 15 of the cam, and the lever 19 isthereby returned to its normal position asshown, in which position thereof,

. the contact 21 will co-act with a fixed contact f -a5 80fto again close the feed circuit for the windtraced.

T is opened at the on position to maintain closed at that point the circuit,f0r the winding of the relay T. Hence for the exact leveling operation of the car, the control of the hoisting operation is under the control of the car switch and the contacts 21 and 80. When the car reaches an exact'level with the landing, the roller 13 engages the incline face of the cam 15, thereby permitting a centering spring 81, automatically to center the car switch. By centering the car switch, the relay winding 9 is deenergized and the relay contacts move to open position, thereby restoring-the switch D tonormal position as shown. The car switch control of the reversing switch relays T and T, dominates over the self-holding circuit I contacts for, said relays, because as will be seen, the self-holding circuit for one, includes back-contacts controlled bythe other.- This in effect means that the car can be reversed at any? point outside of the cam zones, by car switch operation.

If at any time it may be desired to retain control of the hoisting operation solely by means of the car switch, and to preclude operation of the load controlled stopping switch, this can be effected simply by opening the knife switch 50 in the car. This in effect puts therelays T and T solely under the control .of

the car switch, and the feed circuit for thereversing switch windings will be by way of the contacts 37 in a manner hereinbefore It will be seen now that by the use of the loadcontrolled stopping switch the car will for all load conditions be brought substantially level with the landing, or in other words within the bounds of the exact leveling zone, and this zone may extend only a few inches either side of the landing level, and hence the duration of contact necessary to effect the exact leveling is ofsuch short duration that the motor will not attain any appreciable speed such as might cause an over-run movement. Reducing'the leveling zone in a manner as affected by the load controlled stopping switch precludes any need for very slow speed operation, and thus the present day standard motor as used for high speed elevators can be used without the provision of any auxiliary means to effect a very slow speed movement of the car. I

If during loading and unloading, the car platform should tend-.to move from a level with a landing by reason of the hoisting cables untwisting or twisting, the car switch will then be actuated automatically by the leveling cams 15 or 16 and associated parts connected to the car switch, to control the hoisting motor to return the car to a level with the landing and automatically stop the car thereat, thereby maitaining in effect the car level with the landing duringloading and unloading.

6' For the heavy load ascending condition, it

has been shown that the contact sector 18 is actuated a maximum distance and when the transfer of the control of the hoisting operation is made at the point 77, the load controlled stopping switch then continues the hoisting operation to move the car through the maximum coasting zone, and when the ear reaches thehninimum coasting zone, the hoisting operation is automatically discontinued and the birake is applied, and under such load condition and direction of car travel, the car willcoast a minimum" distance andby so doing -inove within the bounds of the exact leveling zone.

c WVith a light load ascending, the hoisting niotog at starting will draw a-current of comparatively small valueiand the current solenoid being subjected to-this current will not actuate the contact sector 18 against the actionof'th'e spring 25, and the contact sector 18; will remain in normal position as shown in Fi'gig3', in which the contacts 21 and 22 are in actuated position. Hence it will be seen that under this load condition and direction of ear travel, when the transfer of the control of hoisting-operation willnot be continued at said point because the sector '18 has not been 1 moved into position to be engaged by the contact 21 and hence the car will under such load condition and direction of car travel, coast its maximum distance through the maximum coasting zone, and in this Way'come to. a gravi't'y stop within the bounds of the exact level- 40 ing zone. Also, with a heavy-load descending the car will coast itsnnaximum distance, and .11 the motor at starting will draw a current of comparatively small value, hence for such load condition and direction of car travel, the

contact sector will assume the position as illustrated in Fig. 3, thereby permitting the .car to coast. its maximum distance and come to a gravity stop substantially level with the landing without liability of over-running the v landing.

With a light load descending, the car willcoast its'minimum distance, and the' motor at starting will draw a current of comparatively high value and for this load condition and di rection of car travel, the contact sector will assume the position as illustrated in Fig. 5, in which case theload switch continues the hoisting operation in thesamemanner as described in connection with the heavy load as cending condition.

1' With average load condition and either dii i"ection of car travel the hoisting motor at starting will draw an appreciable current such a will energize the current solenoid .to cause its maximum distance as illustratedin Fig.

4, so that when the transfer of the control of the hoisting motor is made at the point 7 7 the load controlled stopping-switch will continue the hoisting operation through about on- 7" half the distance of .the maximum coasting zone, and'upon reaching such point the hoisting operation is automatically discontinued and the brake is applied by reason of the contact 21 disengaging the contact sector 18 and 7 the car will then coast and come to a gravity stop within the bounds of the exact leveling zone. i V Referring now to Fig. 2, the load is meas- 'ured mechanically as for example by providing a spring suspension 90 for the car, and

movemen't of the car as caused by loading and unloading is imparted to a pair of contact sectors 91 and 92, through the intermediary of a cam93 fixed to the cable-hitch-block, and a lever 95 secured to a pivoted lever 96 to p which the sector 91 is attached, the lever 95 carrying a roller 97. The sector 92-is at- .tached to a lever 98 which together with the lever 96 is supported for rocking movementon a fixed pivot 99, said levers rocking the contact sectors 91 and 92 in opposite direc-" tions as effected by a, spring 99, when the roller 9'! follows the incline cam face by w p moving downwardly as effected b compresthe holstmg motor is made at the point 77, the

sion of the supporting springs w en a load is on the car platform. Any movement imparted to the lever 96 by the lever 95 to which it is attached, is also imparted to the lever 98 throu h the intermediary of a pair of links 100, connected at their upper ends to a sleeve 101, slidable on a fixed vertically disposed guide rod 102.- The sector 91 controls reversing sSWltCh winding 6, and additional contacts are providedon the reversing switch relay T which are included in said circuit. Thus it will be seen that the sector 91 independently controls-the feed circuit for the up reversing switch winding and the sector 92 independently controls the feed circuit for the winding of the down reversing switch, and by providingthe two independent contact sectors, the results obtained are identical with those justdescribed in connection with theloadswitch illustrated inFig. 1, in 9 which theload is measured electrically, and since adetailed description would be merely repetition, it is deemed unnecessary.

The; rocking lever 19 in' this instance is provided with an additional arm 106 carrying 2 -a contact 21' to co act with the contact sector car. This will cause the carbody to compress 13o the springs 90 and the downward movement as caused y the load will permit the sprlng 99 to actuate the lever 95 in accordance with the rocking movement of the roller in following the incline face of the cam 93, and in this manner the two contact sectors 91 and 92 through the link connection will be rocked in opposite directions from the normal position as shown. Hence if the down relay T is closed, its'conmots-105 render the sector 92 and its associated contact 21' operable to control the stopping operation, and for this load condition it will be seen that the sector 92 has lieen moved its maximum distance in a counterclock-wise direction in which position it is entirely overlapped by its-associated contact- 21 when the latter has been .actuated by the actuating winding 30. On the other hand,-if the up relay T is closed, its contacts 103 render the sector 91 and its associated contact 21 operable to control the stopping 0 eration, and for said heavy load condition, t e sector 91 has been moved its maximum, so that its associated contact 21 will in its return movement from actuated position, travel over the to the closing of switch G, the feed circuit for the reversingfswitch' winding will then be controlled by the load switch contacts and the relay contacts '103 or 105. The stopping cani33 is in this instance provided with a raised ver ical extension 127- at each end and the leveling cams 15 and 16 are elongated so that the ear switch will be actuated auto- Inatically when the. rollers 13'enga e their respective cams, to effect slowspeed operae tion of the car and at the same time transfer -the control of the slow speed operation of the car to theload stopping switch opening the circuit of the windings": 1171 and 3O at the'-= car switch contacts 64, such transfer and new dovgn being automatically efi'ected' by actuation-of the car switch-when :the car is at such a fiointthat the rollen32 will ,ifiitially engage the--highportion of the cai n 33 at the po nt designated 127 lIheslo'w. speed operation of the car will continue until the roller 32 rides down the rat-her sharpshevel 118 at which point themaiximum coasting \zone be ins,the roller in. following the sharp bevel permitting 'quick movement 019.

entire length of the sector 91, and :in this fh e contacts 21 and '21. to aposition' froinf manner continue the hoisting operation in a whi h' 'th take up prgper jcolltggl f th manner as hereinbefore described in connec tion with Fig. 1. v v In Fig. 2, a two speed motoris illustrated,

- fast speed being obtained by operation of a fast and slow speed switch 106, which when actuated by an 'electro-magnet '107, introduces a resistance 108 in the circuit of the shunt field winding 3; Usual fast speed contacts 109 are provided on the car switch to control the operation of the fast and slow speed switch-106. A self-holding circuit for the winding 107 is closed by way of contacts 111 controlled vby'the switch D, wire 110, contacts 112, wire 113, through winding 107, wire '114, through contacts'115 which are closed-when the last arm on the accelerating magnet (not shown) operates and thence to the minus line by We of wire 116. (The. transfer of this self-holdlng circuit to a switch G is effected by centering the car switch F after it has been operated to initiate the start of the car and effect its operation at fastspeed, and by centering the car switch at this time the windings 117 (of switch G) and 30 are put under the controlof the car switch in centered position. The feed circuit for the reversing switch windings 6 and 7 is initially closed by way of the contacts 37 on the switch D and is directed .to the proper reversing switch winding by whichever relay T dr T'is. closed as efi'ected by operation of the car switch. In this case range of movement of the contacts 21 and 21' is-extended so that by actuation thereof by the winding 30 they will over-lap slightly their. respective contact- sectors 91 and 92 with the sectors in normal position as shown, and hence when the switch D operates due and the direction of-car travel, the etfectb'eiiijg ,1 to d1scont1 e the hoistingope'ration sooner 105.

for a heavy oad descending and a light load ascending, than for. a heavy load ascending and a light load descending a In'connection with 2'the method of -obtaining fast speed operation has been de- 11 scribed-in detail and suflicient illustration 1 is thought to be given in connection with the slow speed operation as will give a clear understanding of such operation since cir-' cuits not touched upon are identical with Us those illustrated and described in detail in Fig; 1, and hence to illustrate and describe suc I in detail would be mere re etition.

In Fig. 6, the load controlle switch is of a modified construction adapted to measure the load electrically as in the construction illustrated in Fig. 1., In this construction the lever 119 carries a pivoted switch arm 120 having a roller 121 which by rocking movement of the lever as by energizing the winding 30, initially closes contacts due to the roller 12] engaging a fixed cam 123, and

an additional cam 124 carried by a pivoted arm 125 is rocked a variable number of degrees by energization of the current solenoid in a path to be engaged by the roller 1521 and by so doing impart a further rocking movement to the switch lever to close contacts. The two cams 123 and 124 are off-set from each otherand the roller 121 is of sufficient width to be engageable by both. The

contacts 126 correspond to the contact sec tor 18 and the contact 21 as to function and as will lie obvious the cam 124 through its variable range of movement, varies the time period through which the contacts will be maintained closed as when the lever 119 is moving to its return or; normal'posltion as illustrated, and the contacts 122 as to func tion correspond to the sector 23 and the con-=5- tact 22 in Fig. 1.

It will be pointedout in connection with the load controlled switch as embodied herein that it is not dependent for its adjustment on the stretch orcontraction of the hoisting cables and because of the fact that as herein provided, the timing of the control of the hoisting operation by the load controlled stopping switch is alwaysefl'ected at a predetermined fixed point relative to any predetermined landing, thereby eliminates stretch and contraction of the hbisting cables as a factor or as a contributing cause for the ear over-running or under-running the desired landing. Hence the other predominat ing factor which gives rise to over-run and under-run which factor is the variablecoast of construction of arrangements of parts,

- due to varying load conditions is successfully taken care of by the present invention in such a manner that the car under any condition of loading will. coast to a gravity stopsubstan- -tially level with the landing without liability of over-running. Qver-running as compared with under-running involves greater lossof time, and the oscillation of the car to level it is discomforting to the passengers, wasteful of power, and deteriorative to the hoisting apparatus. v Havin thus described ,the invention and without l miting myself to the precise details what I claim as new and desire to protect by Letters Patent of the UnitedStates is i 1. In an eleyator system, the combination with the car, a hoisting motor, and means operable solely in accordance with the load as measured by the current in the armature'of said motor, to discontinue the hoisting o era; tion of said motor with respect to a predeter-- mined stopping point, sooner for a heavy load descending and a lightlload ascending, than for a heavy load ascending and a light load I: descending. 1

2. 'In'an elevator system, the combination wlth the car, a hoisting motor, manually controlled means and means on the car operable in accordance with the load and independ- V 1 ently of the stretch and contraction of the hoisting cable, to discontinue the hoisting operation with respect to a stopping point predetermined by actuation of the manually controlled means, sooner for a heavyload descending and a. light load ascending, than .for a; light load descending and aheavy load ascendingfso that the car by its coast will come to a gravity stop substantially level with the landin 3. In an elevator system, the combination with the car,'a hoisting motor, and a circuit controller for the motor having a timing movement only during movement of the car through a maximum coasting zone at a predetermined landing.

4, In an elevator system, the combination withthe car, a hoisti ng motor, a circuit controller for the motor having a timing movement only during movement of the car in either direction through a maximum coasting zone, and'means to open-circuit said circuitcontroller to discontinuev the hoisting o eration,of said motor at difierent points within the bounds of said coasting zone, depending on the load and direction of car travel, so that the coast of the car will bring it to a gravity stop substantially level with a. landing;

5. In an elevator System, the combination with the car, a hoisting motor, a circuit-controller to control the operation of said motor,

means to imparta timing movement to said circuit controller directly in accordance with the movement of the car, and means to openclrcuit said circuit controller, dependent on the load and direction of car travel, at any point within range of its timing movement.

6. In an elevator system, the combination with the car, a hoist-ing motor, a stopping switch adjusted automatically in accordance with the load, to' vary the point at whichthe I hoisting operation is discontinued so that the E631 by coastinghwill come to a gravity stop substantially level -with a pie-determined stopping point, and means to time the operation of the stopping switch" only during travel of theater in either direction through a predetermined zone related to a pre-determined;

stopping point. p a a 7. In an elevator, system, the combination with the car, a hoisting motor, a stopping switch, means to time the operationbf the stopping switch to discontinue the hoisting operation of said motor only during travel of 8. In an elevator system, the combination with the car, a hoisting motor, fl-eStOPPlIl,

switch, means to time theoperation of said switch, means to render said timing operation I point relative to any pre-determined stopping point regardless o stretch or contraction of the hoisting cables, and means controlled automaticallyxhy the load to vary within the range of said fixed point and said p'r'e-determined stoppin point, the point atwhich'said stopping switc is open circuited so that the car by itscoast' in either direction wi lconie to a gravity stop substantially level with said stopping point without liability of over-rum ning s 'd point regardless of the capacity of the o'ad; v

9. In an elevator system, the combination with the car, a hoisting motor, a stopping switch, means to initiate the start of the car, means to transfer the control of'the hoisting operation exclusively to the said stopping switch always at a pre-determined fixed point relative to any pre-determined stopping point, and means controlled automatically by Y the load to vary within the range of said fixed 1 point and said pre-determined stopping point,'the point at which said stopping switch 18 open-circuited-so that the car regardless of the capacity of its load will by'coasting, come to a gravity stop substantially level with said stopping point without liability o-f \over-running said point. I

10. In an elevatorsystem',the combination with the car, a hoisting motor, a stopping switch, means to initiate the start of the car,

, means to transfer the control of the hoisting operation exclusively to said stopping switch always at a pre-determined fixed point rela tive to any pre-determined stopping point, means automatically to time the operation of said switch rendered efiective only when the car reachessaid fixed point,and means controlled automaticall by the load to vary within theboundso said points, the point at which the hoisting operation is discontinued, said hoisting operation 'bein discontinued sooner for a heavy load descen ing and a light load ascending, t an for a heavy load ascend-v ing and a light loaddescending. a

11. In an elevator system, \the combination with the car," a hoist ng motor, a stopping switch, cans to initiate the start of the car, means independent of said initiating means automatically to control the hoisting operation to continue movement of the car, means operable automatically to transfer the control qf the hoisting operation exclusively to said stopping switch always at a pre-determined fixed point relative to any pre-determined 1 stopping point, and means controlled automatically by the load to vary within the bounds of said points, the point at which said stopping switch is open-circuited, so, that the hoisting operation is discontinued sooner for ajheavyload descending and alight load as cending than for a heavy load ascending and j a. light load desendin and the car'by coast-f "a ing under thesecon "tidns w illfco'me to a ,oss

gravity stop substantiall level with the stopping point without liab 'ty 6f over-running. 2. In an elevator system, the combinati0n with'the car, a hoisting motor, a car switch to initiate the start of the car, means operable by centering the car switch automatically. to continue the movement of the car, anda stoppin switch controlled automatically by the 10a and rendered operable to conti'ol the hoisting with the car, a hoisting motor, means to initiate start of the car, a stopping switch controlled automatically by the load to vary the point at which the hoisting operation is discontinued so thatthe car by coasting will come to a gravity stop substantially level with a landing, and means operable automatically to bring the car to an exact level with the coast the car does not come to'a stop at an exact level with the landing.

15. In an elevator system,'the combination with the car, aho'isting motor, a car switch to control the hoisting operation, a stopping switch controlled automaticall by the load to vary the point at which the oisting operation is discontinuedy so that the car by coastingwill come to a gravity stop substantially level with a landing, and. means automatically to actuate said car switch to exactly level the car.

16. In an elevator system, the combination with the car, a hoisting motor, a load controlled stopping switch, and means automatically to time the operation of said switch durin mpvement of the car ineither direction ony in a pre-determined zone related to a .pre-determmed landing.

in movement of" the-carin either direction o y in a predetermined maximum coasting zone related to a pre-determined landing.

18. In an elevatorsystem, the combination with the car a hoisting motor, a. load controlled stoppmg switch,;and'm eans comprising a cam to time the operation of said switch during movement of the car only in a predetermined maximum coasting zone related to a pre-determined landing.

19.- In'an elevator system, thecombination with the car, "a hoisting motor, a load our ngif Subsequently to its coast and by its loll Ill

trolled stoppin switch, and means compriscontrol stopping of the car, adjustable independently ofmovement of the car as caused by stretch and contraction of the hoisting cables, and means operable by movement of the car to time the operation, of said switch.

21. n an elevator system, the combination with the car, a hoisting motor, a switch to control stopping of the car, means comprising a cam operable by movement of the car only through a pre-determined maximum coasting zone related to a pre-detern'iined landing, to time the operation of said switch, and means to adjust said switch automatically in accordance with the load to vary with respect to the position of the car within said zone, the point. at which said switch is opencircuited to discontinue the hoisting operation, so that the car regardless of load capacity will coast in either direction to a gravity stop substantially level with the landing car.

without ing,

22. In an elevator system, the combination with the car, a hoisting motor, a load conliability of over-running said landtrolled switch on the car automatically to control the stopping of said motor, and a cam to time the operation of said switch and having a maximum timing operation proportional to a maximum coasting distance of the 23. In an elevator system, the combination with the car, a hoisting mbtor, circuit-controlling mechanism automatically to control the stopping of said motor, a cam to time theoperation of said switch and having a maximum timing operation proportional to a maximum coasting distance of the car, and means controlled automatically by the load with respect to the position of the car relative to said cam, to vary the pointat which said circuit-controlling mechanism is open-circuited to discontinue the hoisting operation, so that the car will, regardless of the capacity of its load, coast in either direction to a gravity stop substantially level with the landing without ing.

24. with the car, a hoisting motor, a switch auto-' matically to control the stopping of said motor, a cam to time the operation of said switch, and means controlled by the load independ-' ently of movement of the car as stretch and contraction of the hoisting cables,

liability of over-running said landto vary the point at which said switch is opened to discontinue the hoisting operation, so that the car will-regardless of stretch and contraction of the hoisting cables, coast to a gravity stop substantially level with the land- I with the car,

In an elevator system, the combination caused by ing without liability of over-running said landing.

25. In an elevator system, the combination with the car, a hoisting motor, circuit controllingmechanism, means adjustable automatically by the load to vary the point at which saidcircuit-controllingmechanism is open-circuited to discontinue the hoisting operation, so that the car will come to a gravity stop substantially level with the landing by coasting variable distances as dependent on car load and direction of car travel, and means automatically to exactly level the car if subsequently to completing its full coast the car is not at such an exact level withthe landing, said leveling means operating automatically to maintain the car at such an exact level during loading and unloading.

26. In an elevator system, the combination with the car, a hoisting motor, automatic means to level the car with a landing, and means to permit time periods of different duration to elapse to permit the car fully to complete coasting as dependent upon load and direction of car travel, such complete coasting bringing. the car to a substantial level with the landing and within the bounds of an exact leveling zone before said automatic leveling means is efiiective to control the car.

27 In an elevator system,'the combination a hoisting motor, automatic means to level the car exactly with a landing, and means operable automatically to introduce time periods of different duration to permit the car to fully complete its coast and come to a gravity stop within the bounds of a predetermined zone corresponding to an substantial level with the landing and without liability of over-running said landing, before said automatic leveling means is rendered effective totake up the control of the car.

28. In an elevator system, the combination with the car, a hoisting motor, a car switch to control operation of the hoistingmotor, a stopping switch adjustable automatically in accordance with the load, a cam to time the operation of said stopping switch, and electro-responsive means operable by moving said car switch from on to off position to render said timing switch operable to coact with said cam.

29. In an elevator system, the combination with the car, a hoisting motor, a car switch to control operation of the hoisting motor, a

stopping swltch adjustable automatically in accordance with the load, a cam proportional in length only to the maximum coasting distance of the car, and electro-responsive means operable by moving said car switch from on to off-positi0n to render said stopping switch operable to co-act with said cam.

30. In an elevator system, the combination with the car, a hoisting motor, meansto initiate start of the car, a switch automatically to continue movement of the car, and means controlled by the load" independently of movement of the car as caused by stretch and 'contraction of the hoisting cables to control said switch to open to discontinue the hoisting operation at varying-points relatively to anypre-determined landing, so that the car I by coasting will come to a gravity stop substantially level with the landing without liability' of over-running said landing.

In testimony whereof, I have signed my name to this specification.

ERNEST L. GALE.

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