US1725772A - Electric elevator system - Google Patents

Description

27, 1929. R. A. WAITE ET AL r 1,725,772

ELECTRIC ELEVATOR SYSTEM Filed June 18, 1924 'Z'SheetS-Sheet 1 'R M QA/VM amvcuiou W, LMM

Patented Aug. 27, 1929.

UNITED STATES 1,725,772 PATENT OFFICE.

RAYMOND A. WAITE AND GEORGE W. LAUTRUP, OF YONKERS, NEW YORK, AS- SIGNORS TO OTIS ELEVATOR COMPANY, OF JERSEY CITY, NEW JERSEY, A COR- PORATION OF NEW JERSEY.

ELECTRIC ELEVATOR SYSTEM.

Application filed .Tune 18,

another, stopping, reversing, and leveling at the various landings.

The system according to the present invention includes a hoisting motor, a motor generator set adapted to supply power to said hoisting motor at a variable voltage for operating it in either direction at various speeds, a brake adapted to have a slow, medium and quick operation in its application, a governor operative for regulating fields of the hoisting motor and generator in the event of the motor operating above a predetermined s cod, and various devices used in connection with the operation of the hoisting mechanism to insure that the elevator car is brou ht level with the landin s accurately and smoothly.

The control system is provided with a car switch in the elevator car for operating the car at normal speeds in either direction and for stopping the car. Leveling switches car ried by the elevator car and adapted to be actuated by cams in the elevator hatchway operate the elevator car for bringing the car level with the landings. The brake has electromagnetic releasing means having con nections with the control system for-a quick application of the brake when the elevator car has been brought to the landing by the leveling switches, for a. medium application thereof during a reversal of the car by the car switch, and a slow application of the brake during the'stopping of the elevator car outside of the leveling zones. The control system also provides a means for momentarily increasing the current in the generator field winding when the elevator car is being leveled whereby the car is brought quickly and positively to the landing level. The generator has a series field winding and means are provided for varying the ampere turns of the series field for a given current through the armature,-as-for example by varying the resistance of a shunt. around the series field so that the effect of the series field is different during operation by the car switch from that during operation on the leveling switch. The brake is provided with a switch for rendering the control system inoperative to accelerate the car above 1924. Serial No. 720,763.

a certain speed until after the brake has been released. The leveling switches in cooperation with cams in the hatchway at the various landings are arranged to operate the control system. and are rendered operative for such purposeduring the retardation of the car before it has come to rest, so that the elevator car is brought smoothly to the landing level. Means are provided in the control system whereby it is possible to bring the car under the control of the car switch at any time during the operation of the car by the leveling switches, and operate it in either direction by the car switch. Certain switches are provided with parallel resistances, or inductances or both in the circuits of their coils for retarding their operation so as to obtain a smooth operation of the elevator car in accelerating, retarding, stopping and reversing.

This invention will be described in connection with the accompanying drawings, wherein one embodiment of the invention is illustrated and in which Figure 1 is a diagrammatic view of an elevator system; and

Figure 2 is a simplified (straight) wiring diagram, of the system illustrated in Figure 1, wherein the coils and contacts of the vari ous switches are shown as separate elements and wherein the letters indicating the-various switches to which the respective coils and c ntacts belong are prefixed to the reference urnerals.

The switch contacts shown sectioned represent the stationary contact elements of the various switches.

Referring to the drawings, the driving motor E with its shunt field EF receives power from the line through knife switch I. This motor drives generator GE, and these two units comprise a motor generator set. The generator GE supplies power of a variable voltage to hoisting motor M. This variable voltage is obtained by control of the separately excited generator field GF. The elevator car K and the counterweight CWT are operatively connected to the driving motor M by cable 1. The operating switch A is located in the car K and serves to control the running of the elevator. A leveling switch L is located on top of the car and in conjunction with cams 2 and 3 located in the hatchway serves to control the leveling of the car with the floor landings. The control system includes reversing, accelerating and relay switches for controlling the operation of the elevator bythe' operating switch A; also other relay switches for controlling the leveling of the elevator car With the various landings. Power for the control circuits is supplied through knife switch- J. The switches are'all shown in their deenergized position, the car being located level with the second floor landing.

Assume that it is desired to run the elevator from the position shown in an upward direction and then stop it at the third floor landing. The operator in the car moves the lever 4 of the operating switch A to the left for an up motion of the elevator. The contact segment 5 of the operating switch A bridges switch fingers 6, 7, 8, 9, 10 and 11 When contact segment 5 bridges fingers 6 and 7 a circuit is completed for the actuating coils of the up reversing switch B and the auxiliary field switch H as follows-from the minus supply line, through knife swltch J, by wire 12, by wire 13, by wire 14, through back contact 15 of down reversing switch C, by wire 16, by wire 17, finger 6, segment 5, finger 7, by Wire 18, through actuating C011 19 of up reversing switch B, by w1re 20, through actuating coil 21 of auxiliary field switch H, by wire 22, by wire 23, by Wire 24, through knife switch J to the plus supply main.

The energization of coil 21 of switch H causes this switch to operate and close its upper contacts and open its lower contact. The closing of contact 25 of swltch H closes the common .feed from theplus supply line to the coils of the accelerating switches D, E, F, and G as will be described below in connection with the circuits for these coils. The closing of contact 26 of switch H short circuits the economizing resistance SR, in series with the field MB of the hoisting motor M the circuit being as follows-from the minus supply line, through switch J, by wire 12, by wire 13, by wire 27, through back contact 28. of switch G, by wire 29, by wire 30,

through contact 26 of switch H, by wire 31,

by Wire 32, through field MF and resistance PFR in parallel, by wire 33, through switch J to the plus supply line. The closing of this circult puts full field on the hoisting motor M. The closing of contact 34 of switch H makes circuit for the magnet of the brake BR as follows: from the minus supply line, through switch J, by wire 12, by wire 35, through contact 34 of switch H, by wire 36, through switch contact 37 on the brake BR, by wire 38, by wire '39, through coil 40 of brake BR, by wire 41,- by wire 24, through switch J to the plus supply line. This results in the release of the brake from the hoisting motor M and opening of the switch contact 37 on brake BR.-

The opening of switch contact 37 on brake BR inserts in series with brake coil 40 a resistance ABR, and the coil of an auxiliary accelerating switch 0 and its series resistance -OR in parallel with resistance ABR. The

of this arrangement is to utilize the time constant of the brake for timing the accelcrating switches, and also for saving power by preventing the acceleration of the car above low speed until the brake has been released. The brake magnet is energized at the same time that poweris put on the motor, but the shoe does not lift at .once because the magnet itself has an inherent time constant and, also because the shoes (and lever arms, not shown in the diagrammatic representation) represent considerable mass which must be set in motion. When contact 37 on the brake .opens, inserting resistance ABR in series with the magnet coil 40, the current is cut down and hence, the'heating of the magnet coil. The switch 0 in parallel -with resistance ABR will operate as the brake shoe lifts, and close its contact 45 for the accelerating switches E, F and G.

The opening of contact 46 of switch H opens the circuit of resistance PBR, which is in parallel with the coil of the brake.

There are two other resistances, PBR and PBR in parallel with the brake coil, the circuit through these resistances being completed simultaneously with the energization of the brake coil. The circuit of these parallel resistances when the lower contact 46 of switch H and contacts. of switch Y are closedis as follows: from the coil 40 of brake BR, by wire 39, by wire 38, through contact 37 of brake BR, by wire 36, by wire 47, by parallel circuits through resistancessistance PBR by wire 52, by Wire 23, to

wi1'e24; the combined circuit from Wire 24 extends by Wire 41 to coil 40 of brake BR. he purpose of these resistances is to control the application of. the brake under different conditions of operation as will hereinafter be described.

The energization of the coil 19 of the up reversing switch B as described above causes this switch to operate and close its upper contacts and open its lower contacts. The switches-B and C are interlocked by means of a walking beam 54 pivotally mounted for engaging catches on the cores 55 and 56 of the switches B and C so'that when one is operated the other is prevented from operating while the 'first one is energized. The closing of the contacts 57 and 58 of switch B'completes the circuit for the field GF of generator GE as follows; from the minus 1 supply line'fth'ro'ugh switch J, by wire 12,

by wire 59, by wire 60, through contact 57 of switch B, by wire 61, by wire 62, through field GF, by wire 63, through coil 64 of relay N, by wire 65, througlrcoil 66 of relay Q,

by wire 67. bv wire 68, through contact 58 of switch B, by wire 69, through a part of resistance GFR to thep'oint 79, by wire 70,

through back contact 71 of relay R, by wire 72, b wire 24, through switch J to the plus supply line. Whilethe circuit for the coils of relays N and Q, is now complete, these relays do not operate as the current is too low due to the resistance GFR in series with I down side of thecar; switch to the accelerating switches respectively.

NVhen the segment 5' of the operating switch bridges fingers 6 and'S, a circuit is completed for the actuating coil 77 of-leveling switch relay T as follows; from the minus line to finger 6 as previously traced, segment 5, finger 8, .bywire 76, through actuating coil 77 of switch T, by wire 78, by wire 52, by wire 23, by wire 24, through switch J to the plus supply line. The switch T closes its contactg 'completing the circuit for the leveling switch motor LM as follows; from the minus supply line, through switch J, by wire 12, by wire 80, through contact 81 of switch T, by wire 82, through wire 83, by wire 24, through switch J, to t 1e plus supply line. The cnergization of the leveling switch motor results in the switch arm 86 with its roller 87 being moved away from the. cam 2 and the switch arm 88 with its roller 89 being moved away from cam 3, these two arms being connected to the motor LM by arm 85 and connection 84. The leveling switch arms are then in such a position that their rollers will not strike the cams 2 and 3 as the car moves and the leveling switch contacts are kept open.

\Vith switches B, H, and T energized as just "outlined, the motor M will run at a speed corresponding to the voltage supplied by the generator GE. The voltage of this generator is increased in successive steps by short eircuiting portions of the resistance GFR in series with the field GF. \Vhen segment 5 bridges fingers 6 and 9, a circuit is completed for coil 94 of the first accelerating switch 1) as follows; from the minus supply line to' finger (i as previously traced, segment- 5, finger 9, by wire 90, through back contact91 of down reversing switch C, y e 92, through series resistance A11 by wire 93, through coil 94 of accelerating switch D, by wire 95, through contact 96 on switch E, by wire 97, through contact 98 on switch Q, by wire 99, through contact 25 of switch H, by wire 22, by wire 23, by wire 24, through switch J to the plus supply line.

Switch 1) is thereby energized and closes its.

top contacts and opens its bottom contact.

The closing of contact 108 of switch D, completes the circuit for the holding coils of switches B, H and T as follows; from the minus supply line, through switrh J, by wire 12, by wire 100, through holding coil 101 of switch T, by wire 102, by wire 103, through contact 73 on switch B, by wire 104, through holding coil 105 of switch B, by wire 106, by

wire 107, through contact 108 of switch D,

by wire..109, by wire 110, through holding coil 111 of switch H, by wire 22, by wire 23, by wire 24, through switch J to the plus supply line, This circuit for :the coils of switches B, H, and T is independent of the circuits originally completed for the actuating coils of these switches. The opening of back contact 112 of switch D' removes the shor t circuit around. coil 101 of switch '1, this contact bein of this coil by wires 113 and 114.

a The closing of contact 118 'of' switch D short circuits a portion of resistance GFR as follows; frompoint 115 -in resistance GFR, by wire 116, by wire 117, through contact 118' of switch D,-.by wire 119, to point 205.

connected to the two ends ltesistance XFR has a short circuit as fol.-

accelerating switches when car switch A 5, finger 10, by wire 124, through resistance AR by wire 125, through contact of auxiliary accelerating switch 0, by wire 126, through contact 127 of switch D, by wire 128, by wire 129, through coil 130 of switch E, by wire 95, through contact 96 of switch a E, by wire 97, through contact 98 of switch Q, by wire 99, through contact 25 of switch H, by wire 22, by wire 23, by wire 24, through switch J to the plus supply line. Resistances ARP and ARP are in parallel with the coils of switches D and E respectively; the circuit for resistance ARP being from coil 94 of switch D, by-wire 95, contact 96 of switch E, by wire 97, contact 98 of switch Q,

by wire 99, through resistance ARP by wires 131 and 93 back to coil 94; and the circuit through ARP being, from-coil 130 of switch E, by Wire 95, contact 96 of switch E, by wire 97, contact 98 of switch Q, by wire 99, through resistance ARP by wires 128 and 129 back to coil 130. These resistances have .no function during the closing of switches Dand E but act when the switches are deenergized. Switch E is energized through the circuit above traced and opens its bottom contact 96. The opening of bottom contact 96 opens the short circuit extending from inductance 140, by wire 95, through contact 96 of switch E,-by wire 97, through contact 98 of switch Q, by wires 99 and 141, back to inductance 140, so that inductance 140 is inserted in. the circuit of coil 130 of switch E. The insertion of inductance 140 in the circuit of coil 130 of switch E delays its action in closing its top contacts. The

closing of contact 134 of switch E short circuits another portion of the resistance GFR as follows; from point .132 in resistance GFR, by wire 133, through contact 134 of switch E, by wire 117, through contact 118 of switch D, by wire 119, .to point 205 of resistance GFR. By thus short circuiting another "portion of the resistance GFR, the

voltage supplied by the generator GE is further increased and the hoisting motor M runs at an increased speedfv The closing of' contact 135 of switch E completes the circuit for coil 139 of the third accelerating switch F as follows: from the minus supply line to finger 10 aspreviously traced, by wire 124, through resistance AR, by wire 136 through,

contact 135 of switch E, by wire 137, by

wire 138, through coil 139 of switch F, by

wire 95, through inductance 140, by wires 141 and 99, through contact 25 of switch H, by w1res22, 23 and 24, through switch J to voltage supplied by coil 139. Switch F will then operate, its

action being delayed by the inductance 140 in series with its coil. The closing of contact 144 of switch F short circuits another portion of resistance GFR as follows; from point 142, by wire 143 through contact 144 of switch F, by wire 133,through contact 134 of switch E and contact 118 of switch D to point 205. By thus short circuiting another portion of the resistance GFR, the the generator GE is further increased and the speed of the hoisting motor M is increased.

By the time switches E and F have closed, the current in the generator field GF has increased sufliciently to cause the switches Q, and M, the coils of which are in closed establishes a holding circuit for the, coils of switches B, H and T, that is independent of switch D.

When segment 5 of operating switch A bridges fingers 6 and 11,.a circuit is completed for the coil 150 of the fourth accelerating switch G as' follows; from the minus supply line to finger 6 as previously traced, segment 5, finger 11, by wire 146, through resistance AR by wire 147, through contact 148 of switch F, by wire 149, through coil 150 of switch G, by wire 95, through inductance 140, by wire 141, by wire 99', through contact 25 of switch H, by wire 22, by wire 23, bywire 24, through switch J to the plus supply line. Switch G closes its upper contacts and opens its lower contact as a result of the completion of this circuit, its action being delayed by'the inductance 140 in series with its coil. The closing of, contact 153 of switch G short circuits another portion of the resistance GFR as follows; from the point 151 in resistance GFR,

GE is further increased and the speed of the hoisting motor M is again increased The opening of lower contact 28 of switch G opens the short circuit by wires 27, 13 and 29 .around.- resistance SFR to insert it in series with the field MF of'hoisting motor M, thereby weakening this field and causing the motor to run faster. Previous to the opening of contact-"2351M switch G, the coil 154 of switch Z wasshort circuited by energized at this time to cause this switch to operate. The circuit for the coil of switch Z is as follows; from the minus supply line through switch J, by' wire 12, by wire 13, through series resistance ZR,

' through coil 154 of switch Z, by wire 155,

by wire 32, through the field MF, by wire 33, to the plus supply line, and resistance SFR is connected across coil 154 of switch Z and resistance ZR, one end of resistance SFR being connected with resistance ZR and the other by wires 29 and 30, through contact 26 of switch H, by wires 31,- 32 and 155. Contact 158 of switch Z together with the contact 160 of switch G short circuits the last portion of resistance GFR as follows; from point 156 on resistance GFR, by wire 69, by wire 157, through contact 158 of switch Z, by wire 159, through contact 160 of switch G, by wire 152, through contact 153 of switch G, by wire 143, through contact 144 of switch F, contact 134 of switch E, and contact 118 of switch D to point 205. By thus short circuiting all of the resistance GFR, the generator supplies full voltage to the hoisting motor M and the latter runs at full speed, hoisting the elevator car at its full speed. I

It is to be noted that the opening of the short circuit around inductance 140, as described in connection with the operation of switch E, connects one end of this inductance to one end of each of the coils of switches D, E and F, while the other end of inductance 140 is connected through resistances ARP, ARP and ARP with the other ends of the coils of switches. D, E and F respectively. The object of this inductance ,is for timing the closing of switches E and F and in conjunction with parallel resistances, the opening of switches D, E and F. It is to be further noted that inductance 140 is in the circuit of-the coil of switch G, the purpose being for timing its closing but ithas no effect in timing its opening.

In the eventthat the elevator car shouldexceed the rated speed, after the resistance GFR has been entirely short circuited and the resistance SFR inserted. in series with the motor field MF, a governor GOV oper-- ates to short circuit the resistance SFR and at the same time to de'energize switch Z. Governor GOV is shown driven from" tire shaft of motor M, and is provided with a contact 161 which is normally open. When the rated speed of the elevator car s exceeded, the governor closes this contact and coil 154 of switch Z and its series resistance ZR, and resistance SFR in parallel therewith are short circuited as follows: from resistance SFR, and resistance ZR, by wire 13, by wire 12, through contact 161 of the governor switch, by wire 162, by wire 32, by wire 155 to the other side of coil 154 of switch Z, which is connected by wires 32 and 31 through contact 26 of switch H, by wire 30, b wire 29, to the other side of resistance S R. The

resistance SFR is thus cut out of the circuit of the motor field MF, and the deenergization of switch Z reinserts the last portion of resistance GFR in the circuit of the generator field GF so that the speed of the motor is decreased by the combined effect of change of field strength of both the hoisting motor and generator.

Thus at full speed of the elevator the switches B, D, E, F, G, H, N, O, Q, T and Z are energized, the switches C, P, R, V, X and Y being deenergized, all of the latter switches except C, which is the down reversing switch, being used only during the leveling operation.

When the car approaches the thirdfloor landing, the operator centers the car switch A, thereby disconnecting the fingers 7, 8, 9, 10 and 11 from the feed finger 6. The last accelerating switch, G, will open immediately, there being no resistance in parallel With the coil of this switch to delay its opening. The opening of the upper contacts of this switch inserts part of the resistance GF R in series with the field GF of generator GE, thereby causing the voltage of the generator to be lowered and the speed of the hoisting motor M to be correspondingly reduced. The closing of the lower contact of switch G short circuits the resistance SFR and the coil 154 of switch Z, causing the latter to open its contact. The strength of field MF is thereby increased resulting in a reduction in speed of hoisting motor M. The accelerating switches D, E and F then open, the opening of these switches being delayed by the elfect of the inductance 140 in series with their coils and the resistances ARP ARP and ARP in parallel with'the inductance and the coils. By properly proportioning these resistances and the inductance, the desired delayed opening of these switches can be obtained. The opening of these accelerating switches inserts the resistance GFR-in successive steps in series with the generator field GF, causing the voltage of this enerator to be reduced and thereby gra ually reduce the speed of the hoisting motor M.

As each step of the resistance GFR is inserted in series with the field GF, the strength of the latter is reduced. A sudden change is prevented, as each step-of resistance is inserted, by the action of the resistance GPR in parallel with the field GF and coils of switches N and Q. The circuit vfor this resistance is as follows; from one end of field GF, by wire 62, through resistance GPR, by wire-68, by wire 67, through coil 66 of switch Q, by wire 65, through coil 64 of switch N, by wire 63 to the other end of field GF. This arrangement also delays the opening of switches N and Q, the contact of switch Q remaining open to keep inductance 140 in the circuit with the accelerating switches for timing their operation in opening, and the contact of switch N maintaining the circuit of the holding coils of switches B, H and T.

, When switch D opens, its back contact 112 closes and short circuits the holding coil 101 of switch T- This causes switch T to open and disconnect the leveling switch motor LM from the line.- The arm 85 of the leveling switch L will move downward, tending to move the arms 86 and 88 toward the cams 2 and 3 respectively. Assume that the operator in the car centered the car switch when the car was at a distance from thethird floor landing such that, at the time the leveling switch arms drop back, the roller 87 on arm 86 strikes against the high surface 163 of cam 2. This results in the closing of the upper contacts of the leveling switch, thereby completing the circuits for the leveling operation.

The leveling switch has two movable arms 86 and 88, pivoted on an arm 164. Arm 164 is connected with arm 85 and is pivotally mounted. Arms 86 and 88 can move independently of arm 85, but an'upward-movement of arm 85 results in the movement of arms 86 and 88 away from the cams 2 and 3 respectively. Arms 86 and 88 of the leveling switch each have two sets of contacts, those on arm 86 controlling the up motion of the car and those on 88 controlling the down motion, one contact of each set being for fast speed and one for slow speed- When the leveling switch motor LM is deenergized and the roller 87 on arm 86 bears against the surface 163 of cam 2, the up set of contacts of the leveling switch is closed. The closing of contact 169 completes the circuit for the actuating coils of the'up reversing switch 13 and of the switch H as follows; from the minus supply line,through switch J by wire 12, by wire 165, through coil 166 of switch P, by wire 167, by wire 168, through contact-169 of leveling switch, by wire 18,

through coil 19 of switch 13, by wire 20,

through actuating coil 21 of switch H, by-

wires 22, 23 and 24, through switch J to the plus supply line. If the reversing switch B is still energized at this time as a result of switch N not having opened its contact 145,

which is in the circuit of the holding coil 105 of switch B, the closing of contact 169 of leveling switch L, will merely establish a circuit to permit coil 19 of switch B to maintain switch B closed. If however, switch B should have opened at this time, the energization of coil 19 of this switch by the closing of contact 169 of the leveling switch, results in the closing of switchB again and the re-establishment of the circuits to the generator field GF. The closing of the other contact, 171-, of the leveling switch establishes another short circuit around the resistance XF R, this resistance being already short circuited by the contact 122 of switch V as follows; from point 204, by wires 203, 24 and 123, through contact 122 of switch V, by wires 121, 120 and 119, to point 205. The short circuit established by the leveling switch is as follows; from point 205, by wire 119, by wire 120, by wire 170, through contact 171 of leveling switch L, by wire 172, i

by wire 83, by wires 24 and 203 to point 204.

When contact 169 of the leveling switch closes, the coil 166 of switch P is energized and this switch closes its contact, completing the circuit for the coil of switch R as follows; from the minus supply line, through switch J, by wire 12, through coil 173 of switch R, by wire 174, through contact 175 of switch P, by wire 176, bywire 52, by wire 23, by wire 24, through switch J to the plus line. Switch R closes its three upper contacts and. opens its lower contact.

The opening of lower contact-71 of switch R removes the short circuit from the portion of resistance GFR, between points 79 and 205, thereby inserting all'of resistance GFR in the field. The circuit through the resistance GF R is then as follows; from the minus line to point 79 of resistance GFR as previously traced in connection with the operation of switch B, through all of resistance GF R, to point 205, by wire 119, by wires 120.

and 121, through contact 122 of switch V, by wires 123 and 24 to the lus line. 'As above stated, contact 171 o the leveling switch is in parallel with contact 122 of switch V. The'elevator is then running at a speed slightly lower than the lowest speed obtainable by the car switch.

One of the upper contacts of switch R connects the up and down feed fingers 6 and 180, of the car switch A as follows; from finger 6,.by wire 17, by wire 16, through contact 177 of switch R, by wire 178, by wire 179, to finger 180. The object of this contact is to permit the operator in the car to take the control. away from the leveling switch and to operate the car in either direction by the car switch at any time during the leveling operation as will hereinafter be set forth. Without this connection, it would be possible supp for the operator to take the control during the leveling operation only in the direction in which the car is moving;

Upper contact 185 of switch'R completes the circuit for the coil of switch V as follows; from the minus supply line, through.

switch J, by wire 12, through coil 181 of switch V, by wire 1 82, through inductance 183, by wire 184, through contact 185 of switch it, by wire 186, by wire 52, by wire 23, by wire 24, through switch J to the plus y line. Switch V opens its contact 122, but the opening of this contact has no effect atthis time, as contact'171 of leveling switch is closed and in a circuit parallel to contact 122 of switchV. The operation of switch V iii-opening itscontact 122 is retarded by the action of the inductance 183 in series with its coil.

The third upper contact, 190; of switch R completes'the circuit for the coil of switch X asfollows, from the minus supply line, through switch J, by wire 12, through-coil 187 of switch X, through inductance 188, by

wire 189, through contact 190 of switch 1%,,

by wire 191, by wire 52, by wire 23, by wire 24, through switch J to the plus line. A resistance PR is placed in parallel with the coil of switch X and theinductance 188 to regulate the opening of this switch. When the coil 187 of switch X is energized, this switch closes its contact, its closing being retarded by the action of the inductance 188 in series with its coil. I

The closing of the contact of switch X completes the circuit for coil 196 of switch Y as follows; from the minus supply line, through switch J, by wire 12, by wire 192, by wire 193, through contact 194 of switch X, by wire 195, through coil 196 of switch Y, by wire 197, by wire 52, by wire 23, by wire 24,'through switch J to the plus line. Switch Y 'will operate and open its two contacts, 19 and 198. The openingof contact 198 removes a short circuit around a part of resistance FS-which is in parallelwith the series field GSF of the generator GE. .The series field GSF is connected in the cir; cuit between thearmature of the generator GE and the armature of the hoisting motor M, and resistance FS is placed in shunt with this field. WVhen the switch Y is not energized, part of this resistance FS is short circuited by contact 198 of switch Y, the circuit being by wires 199'and 200. The amount of this resistance that is short circuited may bevaried to obtain the desired strength of the generator series field. This field is so wound that without any resistance in parallel with it,'it would have too great an effect for the proper operation of the car. The desired strength of this field is obtained by using alow resistance shunt. By increasing the amount of this shunting resistance when the switch Y operates, the strength of the series field isincreased for the leveling operation. 49 of switch Y opens the parallel circuit around the brake magnet through resistances PBR and PBRF.

lVhen the circuits are closed as just "traced the elevator car is running in the up direction on the high speed of the leveling operation. As the car gets nearer to the third floor landing, roller 87 on arm 86 of leveling switch L runs off the surface 163 onto inclined sur face 201 of the cam 2. This results in the opening of contact 171 of the leveling switch, thereby opening the circuits for the high speed of the leveling operation. The opening of this contact inserts resistance XFR in series with resistance GFR and the generator shunt field GF, causing this field to be weakened. A lower voltage is supplied by the generator GE to the hoisting motor M and the latter drives the car at a reduced speed, which is the low speed of the leveling operation. A condenser C is placed in parallel with the contact 171 of the leveling switch to eliminate arcing when this contact opens.

As the car continues toward the landing, roller 87 remains in contact with surface 201 of can12 and shortly before the car is level with the landing the roller '87 rolls off of surface 261 onto surface 202 of cam 2 thereby opening contact 169 of leveling switch L. The opening of this contact breaks the circuit to the coil 19 of reversing switch B, the coil 166 of switch P and the coil 21 of switch H, thereby deenergizing these switches which open and disconnect the generator field GF and the brake magnet coil 10 from the line.

The holding coils 105 of switch B and 111 of switch H have already been deenergized when contact 171 of leveling switch L opens,

so that these coils have no effect at that time.

The opening of the other contact The circuit to these coils was opened by 1 contact 108 on'switch D and the contact 1&5 on switch N, the latter switch having opened as the current was reduced in the generator shunt field GF.

-- Upon deenergizat-ion of coil166 of switch 1 P, its contact opens. This results in the opening of the circuit through the coil 173 of switch B, so that it opens its upper contacts and closes its bottom contact. The opening of contact 190 of switch R deenergizes coil 187 of switch X which thereupon opens its contact 194, its opening, however. being delayed by the action of inductance 188 in series and resistance PR in parallel with the coil 187, The opening of contact 19-1 of switchX deenergizes coil 196 of switch Y so that it closes its contacts 198 and 49. The

opening of contact of switch R opens- .the circuit to coil 181 of switch V which thereupon closes its contact 122. The closing of contact 122 of switch V, and contact above.

71 of switch R short circuits resistance XFR and the portion of resistance GFR between points 205 and 79. The gpening of contact 177 of switch R opens the connection between the up and down feed fingers, 6 and 180, of car switch A. The closing of contact 198 of switch Y short circuits part of resistance FS in shunt with the generator series field GSF, thereby'decreasing the strength of this field. vContact 49 of switch Y establishes the parallel circuits around the brake magnet coil through the resistances PBR and PBR after giving a quick application of the brake for bringing the car to a stop at a floor when under the control of the leveling switch, the resistance PBR alone beingin parallel with the coil of brake BR during the delayed closing of contact 49. The switches are now in position for the next operation and the elevator car is level with the third fioor landing, theaccuracyof the stop being determined by the positioning of the cams with reference to the landing and the controlling system described.

The above description of the operation of the elevator is for an up motion of the car by both the car switch and the leveling switch. A similar operation is obtained for an operation of the car in the down direction, the operator in the car moving the car switch in a direction opposite to that described above. When leveling inthe down direction, the other set of contacts are closed as a result of roller 89 on arm 88 beingagainst cam 3.

The self leveling operation as described above may be summarized as, follows: On approaching the landing, the operator in the car brings the car switch handle to the center position at such a time as to bring the car to a low speed within the leveling zone, say for. instance, in the high speed zone below 'the landing. This action drops the auxiliary leveling switch T, the contact of which interrupts the current :tor the leveling switch motor and allows the leveling. switch rollers to come into contact with the cam. As it is assumed that the car is in the high speed zone, both high and low speed contacts for the up. direction in the leveling switch close. Switch' P operates, completing circuit for switch R, which makescircuits for switches V, X, and Y as described When the low speed point on the cam isreached, the high speed contact on the leveling switc is opened, thereby inserting resistance XFR in series with the generator shunt field GF and-the resulting decreased voltage of the generator gives a very slow speed to the elevator car. On reaching the end of the cam, the low speed leveling switch contact opens, dropping the reversing switch and applying the brake.

' Should the car overtravel the landing so that the down low speed leveling switch meagre l contact is made by the cam 3, current is supplied to the direction switch G and switch P. Switch P makes circuit for switches R, V, X, and Y as before set forth. As the high speed contacts on the leveling switch are open at the time, resistance XFR would be in series with the generator field GF, resulting in a very weak generator field, if switch V operated .immediately to open its contact 122. Therefore the operation of switch V is retarded so as to leave the resistance XFR short circuited for a short time in order to momentarily provide sufficient voltage for the motor armature to insure the starting of the car upon the leveling switch being closed when the car is in the slow speed zone. The

operation of switch Y in opening its contact 198 increases the resistance of the shunt FS across the generator series field, GSF, thereby causing a greater proportion of the armature current to pass through the series field winding.

The action of the series field is to regulate the voltage on the hoisting motor armature so as to compensate for variations v of load 1n the elevator car.

Switch Y is retarded in opening its con-- tacts by theretarded action of switch X in order to prevent the immediate change in the proportion of armature current flowing through the series field upon the closing of the leveling switch slow speed contacts.

Assuming that the elevator car is traveling in an u direction to avlanding, on the leveling switch, and it is desired to oper ate it downwardly. The coil of switch B is energized and sincethe leveling switch controls the operation of the direction switches B and C, and the bottom contact 74 on switch B has cut off the direct feed from the minus supply to the coil of the direction switch C, it would be necessary to wait until the up leveling operation had been completed except ,for the fact that contact 177 of switch R which is closed during the leveling operation completes a circuit supplying a feed from the minus supply to both fingers 6 and 180 of the car switch A. Movement of the handle 4 of the car switch to the down direction first completes a circuit through the down direction switch C and switch H in a similar manner to that set forth for the direction switch B, but due to the fact that. direction switch B is energized, the walking beam 54 between these switches prevents switch C from operating. Further movement of handle 4 in the same direction to cause the segment 5 to bridge three fin.- gers 180, 206 and 207, on the down side closes the circuit of the coil of switch T which operates to energize the motor LM for raising the arm 85 of leveling switch L. This resultsin the switch arms 86 and 88 with their rollers being moved so as to be out of line of. the cams 2and 3 and thus opens the contacts of the leveling switch. The up direction switch B is thereby deenergized and when it opens, switch 0, which has already been energized, will close. Further movement of handle at will energize the switches D, E, F, G, N, O, Q and Z so as to operate them in the manner set forth in connection with the operation of the elevator car in the up direction. lVhile the elevator car is traveling downward at full speed the remaining switches, 13, P, R, V, X and Y, are dcenergized. I

The control for the elevator affords a smooth operation from one speed to another and in stopping. While in the arrangement disclosed the operation of the car leveling switch Lby motor LM and switch T is controlled from the third finger of the car switch A, it is found desirable in some instances to interchange the order of these fingers and allow it to operate as fourth or fifth in order. In this case either one or two accelerating switches, D, or D and E, may be controlled from the car switchA without shifting the leveling switch L to inoperative position. As a result a continuous operation may he had in bringing the elevator cars of various rated speeds to a slop at the landings.

In order to obtain a smooth operation while stopping or reversing the car, thebrake BB is controlled for quick, medium and slow application. The coil 40 of brake BR has a parallel resistance IBlt across it which is never opened. This prevents an excessive voltage across the 601i when the circuit to it is broken, and the stop at the landing controlled by this parallel resistance is a quick application of the brake to keep the car from sliding past the landing. This operation takes place when stopping by operation of the levelingcswitch, in which case the contact 49 of switch Y is maintained open until the car has stopped, the action of this switch, Y, being delayed by the retardation of switch X. For stops be tween landings, the application of the brake is determined by parallel resistance equivalent to resistances PER, Pill-t and PBR all in parallel for a slow brake application, which brings the oar to rest gradually and without shock. In this case switch Y remains inoperative in the stopping operation and its contacts remain closed, and switch ll opens, closing its contact 46 so that all three resistances are in the circuit. When making a quick reversal "resistances PBR and PER are in parallel around the brake coil so as to give a medium application of the brake, just slow enough so that the brake will not set when making the reversal. Here switch Y renniins inoperative and contact -16'of switch ll does not close. It will be understood that resistances IISR, PBR and PBR are so chosen as to give a discharge path of the proper resistance for the brake coil for each condition.

What is claimed is 1. In an electric elevator system, the combination with a hoisting motor and a variable voltage source of energy therefor, of means responsive to the speed of said motor for jointly controlling the field regulation of said motor and energy input into the motor from said source to decrease the speed of the motor in the event that the motor speed rises to a predetermined value and to increase the speed of the motor after it falls to a predetermined value.

2. In an electric elevator system, the combination with a hoisting motor, of control means therefor comprising a resistance adapted to be inserted in series with the motor field winding, and a variable voltage source of power supply for the motor, and means responsive to the speed of said motor for short circuiting said resistance and de creasing the voltage of said power supply in the event that the motor speed rises to a predetermined value and to increase the speed of the motor after it falls to a predetermined value.

3. In an electric elevator system, the combination with a hoisting motor, of control means therefor comprising a resistance adapted to be inserted in series with the motor field when the motor has reached a cer tain speed, a variable voltage source of power supply for the motor having electromagnetically operated switches adapted to control the voltage supplied, means in the controlsystem for the hoisting motor for operating said switches for increasing the voltage to the maximum and for insertin said resistance in series with the motor lielo, and means operable to short circuit said resistance and operate one of said switches to lower the voltage of the power supply in the event of over speed of the motor.

4:. In combination, an 7 electric motor, avariable voltage generator for supplying energy to said motor, said generator having a iield winding, means for impressing voltage of certain values on said winding to cause the motor to run at normal speeds, and means for impressing voltage of a lower value on said winding to cause the motor to run at a lower speed than normal speeds, said last named means comprising means for initially and momentarily impressing voltage of a higher value than said lower value on said winding.

5. In combination, an electric motor, a variable voltage generator for supplying current to said motor, said generator having a field winding, :1 source of current for said winding, means for controlling the direction of the flow of current from said source to said winding to control the direction of rotation of said motor, means for causing the application of voltage of certain values fro'iif said source to said winding to cause the motor to run at normal speeds in each direction of rotation, and means for causing the application of voltage of a lower value'than said certain value from said source to said winding to cause the motor torun at a lower speed than normal speeds in each direction of rotation, said last named means comprising means for initially and momentarily causing the application of voltage of a higher value than said lower value from said source to said winding.

6. An electric elevator system comprising in combination, an elevator car, a hoisting motor, a variable voltage generator for supplying energy to said motor, control means including a leveling switch operable by movement of the car in conjunction witlr cams in the elevator hatchway for causing the application of voltageof two different values to the generator field winding to causethe motor to operate the car at a fast and slow leveling speed, and means for ating the motor at normal variable speeds in either direction with the power supplied by said generator, and control means for operating said motor at lower than the normal speeds in either direction by energy supplied from said generator at lowervoltages, said last named means comprising means for initially and momentarily causing the application of voltage of a certain value to said winding and thereafter causing. the application of voltage of a lower value than said certain value to said winding.

8. In an elevator system, an elevator car, a hoisting motor therefor, a variable voltage generator for supplying current to said motor, said enerator having a field winding, a source of current for said field winding,

means including reversing switches for controlling the direction of the flow of current from said source to said winding to control.

the direction in which the motor operates the car, means including accelerating switches for causing the application of voltage of certain values from said source to said winding to vary, within certain limits, the

voltage *applied from said generator to said motor to cause the motor to run at normal variable speeds 1n each direction of rotation, and means, including a leveling switch carsaid ried by said car and cams in the hatchway to be below'said certain limits and thus cause the motor to run at a lower speed than normal variable speeds in each direction of rotation to facilitate the leveling of the car at the landings, said last named means comprising means for initially and momentarily causing the application of voltage of a higher value than said lower value from said source to said winding.

9. In an electric elevator system, the combination of an elevator car, a hoisting mo tor, a generator having a separately excited field winding and a series field winding and adapted to supply power to the hoistingmotor at a variable voltage, means for controlling the supply of power to the motor, a

leveling switch actuated by movement of the elevator car for controlling said power supply to the motor, and means controlled by the leveling switch for causing a chan e of the ampere turns of the series field given armature current during the operation of the motor by said leveling switch.

10. In an electric elevator system, the combination of a motor, a hoisting drum and an electrically operated brake, a source of energy for supplying power to the motor and for operating said brake, a control system including means for operating the motor in either direction from the source of power, means fo'rreversingits direction and bringing it to a stop, means for releasing the brake, "and means for regulating the speed with which the brake applies to obtain a slow application of the brake for stopping the elevator car between landings, a medium application thereof on the reversal of the operation of the hoisting motor, and a quick application thereof when stopping at landing-levels. i

11. In an electric elevator system, the combination of a hoisting motor, a variable voltage generator for supplying power'to motor, a control system including direction switches, a plurality of accelerating 7 switches interlocked with said direction switches and with each other for controlling the voltage applied to the motor from the generator, means'for retarding the operation of'the accelerating switches in openin when bringing the motor to a stop, an means operated after the motor has attained a predetermined speed operable to retard the opening the dlrection switches.

12. In anelectric elevator system, the combination xoffa hoisting motor, a variable voltage generator for supplying power to said motor, a control system including direction switches, a' {,plurality of accelerating switches interlocked with said direction opening of said switches, and a switch operated after the motor has attained a predetermined speed and having a retarded action in opening adapted to delay the opening of the direction switches when the motor speed is decreasing.

13. In an electric elevator system, the combination of a hoisting motor, a variable voltage generator for supplying power to said motor, a control system includlng direction switches, a plurality of accelerating switches interlocked with said direction switches and witheach other for controlling the voltage applied to the motor from the generator, a car switch on the elevator car for controlling said switches, a leveling switch adapted to be actuated by cams in the elevator hatchway for operating the elevator car, means controlled by said car switch for displacing said leveling switch to an inoperative position, and means for retarding t e operation of the said direction and inter locked accelerating switches in opening, and means for returnlng the leveling switch to its operative position before the direction switches open.

14. In an electric elevator system, the combination of a hoisting motor, a variable voltage generator for supplying power to said motor, a'control system including direction switches, a plurality of accelerating switches interlocked with said direction switches and with each other for controlling the voltage applied to the motor from the generator, a car switch on the elevator car or controlling said switches, a leveling switch adapted to be operated by cams in the elevator hatchway and adapted to energize said direction switches for 0 rating the elevator car at low speeds and ringing it to, the landing level, and means for rendering the car switchoperative to take the control of said direction switches for operating the elevator car in either direction at any time during the operation of the car by said levelingswitch.

In testimony whereof, we have signed our names to this specification.

RAYMOND A. WAITE. GEORGE W. LAUTRUP.

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