US2145809A - Elevator system - Google Patents

Description

Jan. 31, 1939. R. B. TAYLOR 2,145,309

ELEVATOR SYSTEM Filed June 12, 1937 2 Sheets-Sheet 1 Pi .l.

g ONE FLOOR RUN HIGH SPEED RUN LEVELLIN; UNITS inventor I Haber- :9 B. Taylor, H s A i btorneg.

Jan. 31, 1939.

R. B. TAYLOR ELEVATOR SYSTEM Filed June 12, 1957 2 Sheets-Sheet 2 low",

wfim nB /w wb t r A .me .6 m H R Patented m. 31, 1 939 PATENT OFFICE ELEVATOR sys'mm Robert B. Taylor, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York .Application June 12, 1937, Serial No. 141,946

13 Claims.

My invention relates to elevator systems, more particularly to electric systems of control for elevators and has for its object selective automatic control means for decelerating and levelling the 5 elevator for low speed and high speed runs.

In carrying out my invention I utilize vacuum tube control means such as disclosed in my U. S. Patent 1,910,190, dated May 23, 1933, and U. S. patent to John Eaton 1,910,204 of the same date. In the operation of high-speed elevators it is desirable in making a stop from high speed to begin the deceleration of the elevator some distance, perhaps one floor or more, ahead of the door at which the stop is to he made. For short one floor runs, however, the elevator obviously does not have time to accelerate to full speed and therefore the deceleration for the one floor run for the most efllcient operation should not begin until the elevator is fairly close to the floor. In accordance with my invention I provide a special one floor run or low speed decelerating means with time control means for causing this decelerating means to take control for one iioor runs.

For a more complete understanding of my in vention reference should be had to the accompanying drawings, Fig. l of which is a diagrammatic representation of a system of elevator control embodying my invention, while Figs. 2 and 3 are diagrammatic views showing the control devices on the elevator and in the hatchway.

Referring to the drawings, in the specific embodiment of my invention shown, the elevator car H3 is raised and lowered by a main driving 3 motor H which is connected in a Ward Leonard system with a generator i2 driven at a substantially constant speed by means of a suitable driving motor (not shown). The motor and generator are connected together in a permanent electrical circuit which includes a series winding 53 for the generator and also a commutating winding it for the generator. The motor I l is con trolled by controlling the direction and degree of energization of a separately excited field winding 55 for the generator i 2 which held is connected to the direct current supply mains t6 and H for the desired direction of its excitation by means of reversing switches 58 and I9 operated respectively by the coils and 2!. The degree of excitation or strength of the motor field is controlled by suitably connecting resistances 22,

23, 24 and 25 in circuit with the field winding.

The control of the elevator is centered around' the manipulation of the resistances 12 to 25 inclusive in the circuit of the shunt fleld winding i5. During the starting and acceleration of the motor II, the field resistances are controlled by means of a suitable two-way car switch or controller 26 provided with a, handle 2! which is thrown to the left, as seen in the drawings. for operation of the elevator in a downward direction and to the right for the upward direction. During deceleration, however, the resistances 22to 25 inclusive are controlled automatically in response to the position or the car in the go hatchway, i. e., with respect to the floor to which the stop is to be made, so as to decelerate automatically the elevator at a uniform speed and at the maximum permissible rate without discomfort to the passengers. This position respon- 15 sive deceleration control mechanism embodies electron discharge control devices of the type disclosed in the above mentioned patents and therefore the devices themselves will be described but briefly herein. 20

Each device comprises an electric discharge device 26 of the three element type which is provided with a pair of coils 29 and 38 in its output and input circuits respectively. 'ihese coils are mounted so as to be in mutual inductive relation with each other, although spaced apart somewhat, and thereby maintain the discharge devices normally in an oscillating condition. Under this oscillating condition a suitable relay in the output circuit or the discharge device is in 30 effect deenergized, the radio frequency oscillating current being bypassed through a condenser 3i and the direct current in the output circuit at that time being very low in value as compared with the current required to operate the relay.

Seven of these deceleration control devices 32 to 33 inclusive are shown. The devices are mounted on the elevator in suitable positions such that as the elevator moves in the hatchway control vanes made of a suitable electrically conducting material, such as iron or copper, mounted in the hatchway adjacent each floor pass between the two coils 29 and 38 of each device and temporarily interrupt the inductive inter-linkage between the coils whereby the relay for the discharge device is operated to control the elevator.

In Figs. 2 and 3 the arrangement of the control devices withrespect to the vanes is shown for a typical installation with the elevator levelled at a door. A levelling vane 39 is midway between the devices 36 and 38, the ends of the vane not being between the coils of each device sufliciently to interrupt their omillatory condition. A shorter vane 43 lies between the coils of the device 31 thus interrupting their os- '54 and conductor 52 to main I6.

cillatory condition. The upward one floor run control device 32 cooperates withthe vane 4| while the downward one floor run control device 33 cooperates with the vane 42. In a similar manner, the upward high-speed control device 34 cooperates with the vane 43 and the downward high-speed control device 35 cooperates with the vane 44. I

Assuming now that the elevator is to be started in a downwarddirection, the operation of the control mechanism for each point of the controller 26 will be described in detail for the acceleration. Thereafter the deceleration for high-speed runs and one floor runs and the levelling at the floor will be described.

With the controller in the off position shown in the drawings and the supply mains I6 and I1 energized, the coil 46 is energized, whereby the switches 41 and 48 operated by it are respectively opened and closed. This circuit for the coil 46 leads from supply mains I1 through conductor 49, switch 50, conductor 5|, the coil 46 and the conductor 52 to the supply main I6.

Controller in first position on point 53 This energizes the coil 54 the circuit for which is from the supply main I1 through conductor 49, the controller to point 53, conductor 55, coil The coil 54 opens the switches 56 and 51, but no control function is performed at that time.

Controller in second position on point 58 In this position the coils 2| and 60 are energized in series with each other. This circuit may be traced from main I1 through conductor 49, the controller, conductor 6|, interlock switch 62, coil 2|, coil 60 and conductor 63 to main I6. The coil 2| closes the reversing switches I9 thus connecting the field winding 55 across the supply mains in series with the resistances 22 and 24 in parallel with each other. This circuit for the field winding I5 leads from main I1 through conductor 49, resistance 22, the upper switch of reversing switch I9, the coil I5, the lower switch and conductor 63 tomain I6. The circuit for the resistance 24 is from the main |1 through the switch 68, the conductor 69, the resistance 24 and conductor 10 to the junction with resist ance 22. This energization of the field I5 produces a low voltage in the generator I2 and the elevator starts at low speed. The coil 60 has meanwhile closed the switch 50a which energizes the brake coil 10a to release the brake. The brake coil circuit is from conductor 49 through coil 10a, switch 50a and conductor 63 to main Also, the coil 60 opens the switch 50 thereby deenergizing the coil 46 whereby the switch 41 closes and the switch 48 opens after a predetermined time interval determined by its timing device 48a. It might be noted briefly here that the switch 48 controls the one floor run devices 32 and 33. Its timing device 48a is set to allow the switch 48 to open in about 1 seconds. Consequently, if the controller 26 is moved to the oil position within that period, which would be the case for a one floor run, the one floor, run devices take control, as will be described more in detail hereinafter.

At the same time the coil 2| opened its interlock switch 1| and closed its interlock switch 12 in the output circuit of the down one floor run the down high speed control device 35, and also the interlock switches 14, 15, 16 and 11.

Controller in third position on point 78 erator and the speed of the elevator is increased.

Also, the coil 19 closes its switch 83 thus completing a holding circuit for the coil 2|, this circuit leading from main I1 through conductor 84, switch 83, conductor 85, switch 16, conductor 86, switch 62, coil 2| and, as before, through coil 60 and conductor 63 to main I6.

Likewise, coil 19 closes its switch 81 for its own holding circuit, this circuit leading from conductor 84 through switch 81, conductor 88, switch 89, conductor 90, switch .11, conductor 80, coil 19 and conductor 8| to main I6.

Controller in fourth position on point 91 This closes the circuit for the coil 92 leading from the controller through conductor 93, the coil 92 and conductor 52 to main I6. The coil 92 closes its switch 94 thus connecting the resistance 23 in parallel with the other three resistances for higher elevator speed.

Also, the coil 92 closes its own interlock switch 95 whereby a holding circuit is established for coil 92 from main I1 through conductor 96, switch 91, switch 98, switch 93 and switch 15, conductor 93, coil 92 and conductor 52 to main I6 The coil 92 also closes an interlock switch 99 in a circuit for the coil I00 as well as a switch IOI in the output circuit with the high-speed deceleration unit 35.

This circuit for the coil I00 is from main I1 through conductor 96, switches 91 and 98, switch 99, switch 14, conductor I02, coil I 00, switch I 04, switch I05 and conductor I06 to main I6.

The coil I00 is now energized provided the car speed is high enough to close the switch I05 whose coil I08 is connected across the armature of the generator I2 and therefore responsive to its voltage and hence speed of the elevator. The

purpose of the switch I 05 is to prevent a too rapid acceleration of the car in the event that the controller is moved immediately to the last position in contact with 9|. 1

Assuming that the switch I 05 is closed, the

. coil I00 is energized and closes its switch I09 Deceleration from full speed The controller 26 is thrown to its central 01! position but the elevator continues at full speed until the high-speed down vane 44 for the next floor is reached by the down high-speed deceleration device 35. Because of the fact that the switch III is open the one floor devices 32 and 33 are inactive, but the high-speed device 35, assuming downward movement, is rendered active by reason of the closing of the switch IOI.

Therefore, when the device 35 reaches the vane 44 (Fig. 3) its output circuit is energized sufiiciently to cause the relay coil II 2 to lift up its armature thereby opening the switch 91 in circuit of field winding I5. The elevator now decelerates by regenerativebraking to a predetermined low speed such as 160 or 1'10 feet a minute.

The output circuit of the device may be traced from main I! through conductor IIO,

switch 5-1, conductor II4, switch 41', coil 2,

switch IOI, switch I3, conductor II5, through the pliotron tube 6 and thence through the filament heating conductor I I! to the main I6.

At the same time or course the deenergization of the coil 92 opens the switches 95, 99 and IN, the switch IOI deenergizing the coil II2. Also, the switch I I8 closes as well as the switch 91.

In the next decelerating operation the levelling devices take control. The first downward device 38 engages the vane 39 when the elevator is about 24 inches from the floor whereby the coil H9 is energized and opens the switch 83, thereby deenergizing the coil 19 whose switch 82 opens to disconnect the resistance 25. This leaves the resistances 22 and 24 only in the field circuit whereby the speed is still further reduced.

Also, the deenergization of the coil 19 opens its switch 83, but this does not deenergize the contactor coil 2i because of the closing of a holding switch I20 by the coil II9. Thus the circuit for the coil 2| is from main I'I through the switch I20, conductor I2I to the conductor 86 and thence as before.

The tube control circuit for the relay coil II9 leads from main I! through conductor I I0, switch 51, conductor II4, switch H8, conductor I22, coil I I9 to the plate of the tube I23 and through the tube to the filament heating circuit I I1.

As the elevator continues downward at still further reduced speed, the deceleration unit 31 reaches the vane (Fig. 3). This preferably will occur when the elevator is about eight inches from the floor. It energizes the coil I24 which opens the switch 68 to deenerglze the resistance 24 thus leaving the single resistance 22 in the field circuit. As a result the elevator decelerates to a very low speed. The circuit of the coil I24 is the same as for the coil I I9 up to the conductor I22 from which it leads through the coil I24 to the plate of the tube I25 through the tube to the conductor II! and thence to the main I6.

The final control operation occurs when the device 38 leaves the vane 39 whereby the coil H9 is deenergized and its switch I20 opened whereby the coils 2i and 60 are deenergized. This opens the contactor I9 whereby the field I5 is ,deenergized and opens the switch a whereby the brake coil 10a is deenergized and the brake applied to stop the elevator at the floor.

In the event that the elevator overruns the floor the upward levelling device 36 is activated whereby the coil I26 is energized and the switch I21 closed, whereby the coils 20 and are energized to reverse the elevator with the resistance 24 in the field circuit. This circuit for the coils 20 and 60 leads from main I! through the conductor I28, switch I2I to the conductor I28a, switch II,

' and thence through the coils 20 and 60 to the conductor 63 and the main I6. When the elevator moves back at this very low speed suiliciently to deenergize the coil I26, the field I5 is deenergized and the brake again applied to stop the elevator accurately at the floor.

For onefioor runs the car switch is moved to the full running position and then immediately returned to its central 03 position. As a'result the control circuits previously described are set 5 up with the exception of the energization of the coil I00 which is not energized by reason of the fact that the switch I04 is open. In other words, the accelerating circuits are set up so that the car accelerates with all four resistances 22 to 25 inclusive in the field circuit in parallel with each other.

The coil J29 is at this time energized by reason of the fact that thecoil 54 was deenergized and its switch 56 closed before the switch 48 had timed open. Thus when the switch 56 closed, a circuit was established for the coil I29 from main I! through conductor IIO, switch 56, conductor I30,

switch 48, conductor I 3i, coil I29, conductor I32, switch 50a, now closed, and conductor 63 to the main I 6. The coil I29 closes itsswitch I33 and thus establishes a holding circuit for the coil I29 from main I1 through conductor H0, switch 56, conductor I30, switch I33, conductor I3l to the coil I29 and thence as before to the main I6. Therefore, when the switch 48 opens after its predetermined time interval the coil I29 is not deenergized.

At the same time, the coil I29 opens its interlock switch I04 and closes its interlock switch III in the output circuit of the one floor run deceleration devices.

When the. device 33 reaches its vane 42 (Fig. 3) the coil I34 is energized which opens the switch 98 and thereby deenergizes the coil 92.. This opens the switch 94 leaving the three resistances 22, 24 and 25 in the field circuit in parallel with each other. The elevator now decelerates and the deceleration is continuedby the levelling devices in accordance with the preceding description in connection with the high speed stop.

The circuit for the coil I34 is from the main I'I through conductor I I 0, switch 51, switch III, coil I34, switch 12, conductor I34a, the tube I35 and conductor III to main I6.

Long one floor run Provision is also made for runs for floors of greater height than the other floors. For such runs the car switch is centered at once after being moved to the full running position. When the high-speed device 35 reaches its vane, however, the car will not have had time to attain full speed and therefore should not be decelerated as fast as from full speed for eflicient operation.

The car accelerates with the samecontrol circuits as for a one floor run, but has time to accelerate to a higher speed although not the maxi\ mum speed. The coil I29 isnow energized as previously described. When the high-speed device 35 reaches its vane the coil H2 is energized and closes its switch i36 whereby the coil I3'I is energized and closes its switch I38 whereby a portion I39 of the resistance 23 is connected in parallel with the other three resistances this connection being through the conductor I40. The effect of this is to give increased generator field and delay the deceleration.

Also the coil II2 opens its switch 91 whereby coil 92 is deenergized and switch I0l opened to deenergize coil H2. The switch I36 is therefore opened very quickly after its closing whereby the coil I3! is deenergized and switch I38 released. The switch I38 is a time operated switch and is set to open under the control of suitable timing for the coil 5| as the first point in the downward direction. Thisis also true oi the third and fourth points I and i. The interlock switches 6 to Iii inclusive on the down contactor l8 select the proper down units 32 and 34.

While I have shown a particular embodiment oi my invention, it will be understood, of course,

that I do not wish to be limited thereto since many modifications may be made, and I therefore contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A control system for elevators and the like comprising electric driving means for the elevator, a controller for controlling said driving means to start and accelerate said elevator, a plurality of means for controlling said driving means to decelerate said elevator from respectively high and low speeds, said means being responsive to the position or the elevator and said high-speedmeans being eflective at a greater distance from the desired stop, and means responsive to movement of said controller for selectively rendering one 01' said decelerating means effective to decelerate said elevator.

2. A control system for elevators and the like comprising electric driving means for the elevator, a manually operated controller for controlling said driving means to start and accelerate said elevator, low-speed and high-speed decelerating means for controlling said driving means to decelerate said elevator, said decelerating means being responsive to the position of the elevator and said high-speed decelerating means operating when the elevator is a greater distance from the floor than said low-speed decelerating means, and time controlled mechanism responsive to movement of said controller for rendering said low-speed decelerating means operative to decelerate said elevator from a low speed.

3. A control system for elevators and the like comprising electric driving means for the elevator, a manually operated controller for controlling said driving means to start and accelerate said elevator, low-speed and high-speed decelerating means for controlling said driving means to decel erate said elevator, said decelerating means being responsive to the position of the elevator and said high-speed decelerating means operating when the elevator is a greater distance from the floor than said low-speed decelerating means, and time controlled mechanism responsive to movement of said controller for rendering said low-speed decelerating means operative and for disabling said high-speed decelerating means to decelerate said elevator from a low speed.

4. A control system for elevators and the like, comprising the combination with a hatchway and a car movable in said hatchway, electric driving means for said car, reversing switches for controlling said driving means for forward and reverse operation, resistances in circuit with said driving means for controlling the acceleration and deceleration of said driving means, electromagnetically operated control switches for controlling said resistances, a controller for controlling said reversing and control switches to start and accelerate said car, low-speed and high-speed control devices for said control switches mounted on said car, a pair of members mounted in said hatchway at diiierent distances from the selected floor in position to come into cooperative relation respectively with said control devices and thereby operate said control switches to control the decel-' and deceleration of said driving means, electromagnetically operated control switches for controlling said resistances, a controller for controlling said reversing and control switches to start and accelerate said car, low-speed and high-speed control devices for said control switches mounted on said car, a pair of members mounted in said hatchway at diiferent distances from the selected floor in position to come into cooperative relation respectively with said control devices and thereby operate said control switches to control the deceleration of said car, the member for said low-speed control device being nearer the floor, means normally disabling said low-speed control device, and time controlled means responsive to movement of said controller to its ofl position for rendering eflectlve said low-speed control device.

6. A control system for elevators and the like, comprising the combination with a hatchway and a car movable in said hatchway, electric driving means for said car, reversing switches for controlling said driving means for forward and reverse operation, speed control means for controlling the acceleration and deceleration of said driving means, eiectromagnetically operated control switches for controlling speed control means, a manually operated controller for controlling said reversing and control -switches to start and accelerate said car, low-speed and high-speed electron discharge devices having input and output circuits mounted on said car, a pair of devices mounted in said hatchway at different distances from the selected floor in position to come into cooperative relation respectively with saiddischarge devices and thereby control said out put circuits, the device for said low-speed discharge device being nearer the floor, means included in said output circuits for operating said control switches to control said speed control means and thereby control the deceleration of said car, means normally disabling said lowspeed discharge device, and time controlled means responsive to movement of said controller for rendering effective said low-speed discharge device.

7. A control system for elevators and the like,

comprising the combination with a hatchway and a car movable in said hatchway, electric driving means for said car, reversing switches for controlling said driving means for forward and rein said hatchway at different distances from the.

selected fioor in position to comeinto cooperative relation respectively with said discharge devices upon movement of said car and thereby control said output circuits, the vane for said low-speed discharge device being nearer the floor, means included in said output circuits for operating said control switches to vary the amount of resistance in said circuit to control the deceleration of said car, means normally disabling said low-speed discharge device, and time controlled means responsive to movement of said controller to its off position for rendering effective said low-speed discharge device and for disabling said high-speed discharge device.

8. A control system for elevators and the like, comprising electric driving means for the elevator, a manually operated controller provided with a plurality of positions for controlling said driving means to start and accelerate said elevator, decelerating means for controlling said driving means to decelerate said elevator, said decelerating means being responsive to the position of the elevator, a normally open switch in a control circuit for said decelerating means, means operated by said controller when in one position for closing said switch, means actuated by movement of said controller to a second position for opening a second switch in said control circuit, means actuated by movement of said controller to a third pos'tion for releasing said first switch and for closing a third switch in said control circuit, time responsive means for delaying the opening of said first switch for a predetermined time interval, and means actuated by movement of said controller to a final position for holding said third switch closed when said controller is returned to said one position, whereby when said controller is returned to said one position before said first switch has opened, said second switch closes to energize said decelerating means for deceleration of said elevator from a low running 9. A control system for elevators and the like, comprising electric driving means for the elevator, a manually operated controller provided with a plurality of positions for controlling said driving means to start and accelerate said elevator, decelerating means for controlling said driving means to decelerate said elevator, said decelerating means being responsive to the position of the elevator, a normally open switch in a control circuit for said decelerating means, means operated by said controller when in one position for closing said switch, means actuated by movement of said controller to a second position for opening a second switch in said control circuit, means actuated by movement of said controller to a third position for releasing said first switch and for closing a third switch in said contrcl circuit, time responsive means for delaying the opening of said first switch for a predetermined time interval, means actuated by movement of said controller to a final position for holding said third switch closed when said controller is returned to said one position, whereby when said controller is returned to said one position, before said first switch-has opened, said second switch closes to energize said decelerating means for deceleration of said elevator from a low running speed, and decelerating and levelling control means for said driving means responsive to the position of the elevator for decelerating and levelling the elevator and for thereafter openingsaid third switch.

10. A control system for elevators and the like, comprising electric driving means for the elevator, a. manually operated controller provided with a plurality of positions for controlling said driving means to start and accelerate said elevator, decelerating means for controlling said driving means to decelerate said elevator, said desaid controller is in one position, means operated by movement of said controller to another position for opening a second switch in said control circuit, means operated by movement of said controller to a third position for deenergizing said first switch and for closing a third switch in said control circuit, time responsive means for delaying the opening of said first switch, and means operated by movement of said controller to a final position for establishing a circuit to maintain said third switch closed when said controller is returned to said one position, whereby when said controller is returned to said one position before said first switch has opened, said second switch closes to energize said decelerating means for deceleration ofsaid elevator from. a low running speed.

ll. A control system for elevators and the like, comprising electric driving means for the elevator, a manually operated controller provided with a plurality of positions for controlling said driving means to start and accelerate said elevator, decelerating means for controlling said driving means to decelerate said elevator, said decelerating means being responsive to the position of the elevator, a first normally closed switch for closing a circuit when the controller is in its off position, to close a second switch in a control circuit for said decelerating means, means operated by movement of said controller to a first position for opening a third switch in said control circuit, means operated by movement of said controller to a second position for opening said first switch to deenergize said second switch and for closing a fourth switch in said control circuit, time responsive means for delaying the opening of said second switch, and means operated by movement of said controller to a final position for establishing a holding circuit to maintain said first and fourth switches respectively open and closed when said controller is returned to its oil position, whereby when said controller is returned to its oil position before said second switch has opened, said third switch closes to energize said low-speed decelerating means for deceleration of said elevator from a low running speed.

12. A control system for elevators and the like, comprising electric driving means for the elevator, a. manually operated controller provided with a. plurality of positions for controlling said driving means to start and accelerate said elevator, low-speed and high-speed decelerating means for controlling said driving means to decelerate said is a greater distance from the floor than said lowspeed decelerating means, a first normally closed switch for closing a circuit when the controller circuit to maintain said is in its oil position to close a second switch in a 'control circuit for said low-speed decelerating means, means operated by movement of said controller to a first position for opening a third switch in said control circuit, means operated, by movement of said controller to a second position .ior opening said first switch to deenergize said second switch. and for closing a fourth switch in said control circuit, time responsive means for delaying the opening of said second switch, and means operated by movement of said controller to a final position for establishing a holding first and fourth switches respectively open and closed when said controller is returned to its 01! position, whereby when said controller is returned to its off position before said second switch has opened, said third switch closes to energize said low-speed decelerating means for deceleration of said elevator from a low running speed.

13, A control system for elevators and the like, comprising electric driving means for the elevator, a manually operated controller provided with a plurality of positions for controlling said driving means to start and accelerate said elevator, low-speed and high-speed decelerating means for controlling said driving means to decelerate said elevator, said decelerating means vtroller to a first position for being responsive to the position so: the elevator and said high-speed decelerating means operating when the ear is a greater distance from the fioor than said low-speed decelerating means, a first normally closed switch for closing a circuit when the controller is in its off position to open a second switch to deenergize said high-speed decelerating means and to close a third switch in a control circuit for said low-speed decelerating means, means operated by movement of said conopening a fourth switch in said control circuit, means operated by movement of said controller to a second position for opening said first switch to deenergize said second and third switches and for closing a fifth switch in said control circuit, time responsive means for delaying the opening of said second and third switches, means operated by movement of said controller to a final position for estab-' lishing a holding circuit to maintain said first and fifth switches respectively open and closed when said controller is returned to its oil? position whereby when said controller is returned to its off position before said second and third switches have closed and opened, said fourth switch closes to energize said low-speed decelerating means for deceleration of said elevator from. a low running speed, and time controlled means operated by said high-speed decelerating means after energization of said low-speed decelerating means for decreasing temporarily the rate of deceleration of said elevator.

ROBERT B. TAYLOR.

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