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Publication numberUS2221403 A
Publication typeGrant
Publication dateNov 12, 1940
Filing dateJun 10, 1939
Priority dateJun 10, 1939
Publication numberUS 2221403 A, US 2221403A, US-A-2221403, US2221403 A, US2221403A
InventorsEdward Handy Arthur, Leonard Lindquist David
Original AssigneeOtis Elevator Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Moving stairway handrail drive
US 2221403 A
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Description  (OCR text may contain errors)

D. L. LINDQUIST arm. I 2,221,403

Nov. 12, 1940.

' MOVING STAIRWAY HANDRAIL DRIVE Filed June 10, 1939 Sheets- Sheet 1 "W }INVENTOR5 BY nmw wmryl ATTORNEY N 1940. D. 1.. LINDQUIST ErAL' 2,221,403

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. 1||||| |r||| I ll |H-M a kT wT 4 flinllliln k 5 $111,111? iwilg Patented Nov. 12, 1940 UNITED STATES MOVING STAIRWAY HANDRAIL DRIVE David Leonard Lindquist, White Plains, and Arthur Edward Handy, Lynbrook, N. Y,, assignors to Otis Elevator Company, New York, N. Y., a corporation of New Jersey Application June 10, 1939, Serial No. 278,580

11 Claims.

The invention relates to handrails of moving Stairways and especially to the driving of the handrails.

, Moving stairways are provided with moving handrails for the convenience of persons using the stairways. Two handrails are, provided, one on each side of the stairs, and are arranged to be driven in synchronism with the steps. It has been the practice for a great many years to provide a traction drive for the handrails. In these arrangements, the handrail passes around newel wheels at the ends of the stairway. At one end of the stairway, usually the upper end, the handrail also passes around tensioning wheels positioned between the newel, wheel at-that end of the stairway and the lower run of the handrail.

This newelwheel is driven and at least one oi the tensioning wheels also isdriven to provide sufilcient traction for driving the handrail. 20 These driving wheels are driven fromthe stairway driving motor to rotate at the same peripheral speed.

On both the upper run and the return run of the incline, each handrail slides on guides extendinginside the handrail. These guides have curved portions near the ends of the stairway. There is considerable friction between the handrail and its guides at these points. Also, friction exists between the guides and the handrail on the inclines which may be considerable in case of high rise stairways. Due to this friction a considerable force is required'to drive the handrail and hence a considerable tension must .be maintained in the handrail. As the handrail 35 passes around each driven sheave the tension is greater at the point where the handrail engages the sheave than it is at the point at which it leaves the sheave. Furthermore, the difference in tension in the handrail for one of these wheels is greater than thedifierence in tension in the handrail for the other wheel. The wheel -for which the greatest difference inttension exists is dependent upon the direction of movement of the stairway. Due to this difference in tension in the handrail creepage takes place on each wheel and this creepage is different on the two wheels due tothe fact that the difference in tension is not the same for both of them. In order 50 to compensate for thisdifference in creepage, slippage of the handrail occurs and this takes place in a series of jumps. 1 l

It is the object of the invention to cause smooth operation of the handrail whether, applied to a one-way or reversible stairway.

The invention involves driving at least two of the wheels about which the handrail passes in such way as to permit relative rotative movement of the wheels with respect to each other, .apply (ing torque'to'the respective wheels in an amount is driven from the stairway driving motor and in which a tensioning wheel is driven by an auxiliary motor separate from the stairway driving motor. In carrying out the invention with such arrangement as applied to a reversible stairway, the auxiliary motor is controlled in such way as to provide the proper torque for both descending and ascending operations of the stairway. Such arrangement will be described.

Features and advantages of the invention will be apparent from the following description and appended claims.

In the drawings:

Figure l is a diagrammatic representation in side elevation of a moving stairway embodying the invention;

Figure 2 is a simplified wiring diagram of a control system for the stairway illustrated in Figure 1; and

Figure 2a is a key sheet for Figure 2 showing thfiv electromagnetic switches in spindle form with the contacts and, coils arranged on the spindles in horizontal alignment with the .corresponding contacts and coils in the wiring diagram.

Referring to Figure 1, the moving stairway extends between a lower landing l0 and an upper landing I I. In the arrangement illustrated, the stairway comprises an endless series of steps l2 driven at the upper end of the stairway by means of sprocket wheels through running gear chains (not shown) These sprocket wheels are mounted on and driven by the main drive shaft 13 of the stairway. This drive shaft in turn is driven by an electric motor l4 through reduction gearing I 5, sprocket wheel I6, driving chain I1 and sprocket wheel I8 secured to shaft I3.

The stairway has two endless moving handrails, one on each side thereof, the handrail 20 for one side being illustrated. This handrail extends around newel wheels 2| and 22 at the ends of the stairway. On its upper and lower runs the handrail is guided by elongated guide members extending inside the handrail. Between the newel wheel 32 at the upper end of the stairway and the lower run the handrail passes around tensioning wheels 23 and 24.

In the arrangement illustrated, wheel 24 is a driven wheel and is mounted on a shaft 25 hav' ing a fixed support, while wheel 23 serves as the tightener wheel and is mounted on a shaft 26 supported by a slidable carriage l9. Carriage I9 is connected by means of a cable 21 passing over an idler pulley 28 to a tensioning weight 30 to maintain" the handrail taut. Another cable 3! is connected to the top of tensioning weight 39 and extendsv through a flexible guide tube 32 to a safety device 33. This safety device comprises a pair of limit switches 34 and 35. Each of these switches is biased to open position but is normally maintained closed by means of a latch 35. This latch is operable by cam 3'! adjustably mounted on a lift rod 38 and having a pulley 29 at the upper end thereof. The cable 3| from the tensioning weight 39 passes around this pulley on the left hand lift rod and then up to a fixed support. Thus, upon stretch of 1 a similar manner, the operating cable 39 for 1 switch 35 for that side of the stairway being connected to a similartensioning weight on the oppositeside of the stairway. y

The upper newel wheel 22 for the handrail is driven from the main drive shaft l3 through a sprocket wheel 49 securedto the main drive shaft, sprocket chain 4! and sprocket wheel 42 secured to drive shaft 43 for newel wheel 22. The upper newel wheel for the opposite side of the stairway is'driven in a similar manner from a sprocket wheel on shaft I3. The tensioning wheel 24 is driven by amotor 44 separate from the main driving motor M. The drive shaft 25 for this wheel isprovided with a sprocket wheel 45 which is driven by motor M through reduction gearing 56, sprocket wheel M, sprocket chain 49, sprocket wheel 59 on countershaft a second sprocket wheel 52 on countershaft 5|, and sprocket chain 531 The tensioning wheel '24 for the opposite side of the stairway is driven in a similar manner from'a sprocket wheel on countershaft 5| Referring now to Figure 2, the control system illustrated is for a three-phase alternating current source of power with 'motors'ld and 44 threephase squirrel cage induction' motors. It will be understood, however, that the invention is applicable to other sources of power supply and other types of driving motors. The 'rotorof the main driving motor. I4 is designated 69', while the stator windings of this motor are designated GI, 62 and 63. 'I'he rotor of the auxiliary motor 44 is designated 5.5, while the stator windings of the auxiliary motor are designated 66, 6'! and 68. 10, H and '12 are torque adjusting resistances for motor 4d. 13 is a triple pole main line switch for connectinginthe supply 'mains 14, [5 audit. The feed lines 11 and 18 for certain of the control circuits are illustrated as separate lines but it is to lie-understood that these lines may be fed directly orindirectly from the supply mains. 89 and 8! are key: operated starting switches for'the moving stairway,.these switches being arranged preferably, one;at the upper landing and the other, atvv the lower landing of the stairway. 82 is an electromagnetic release coil for the machine pawl ,brake 83. When the pawl brake is lifted,,i t separates contacts. 84 and engages contacts" 85in; the control circuits- 88 is a. rectifier for supplying current derived'from supply lines 1 Land.1 8, to coil 8,2.., This rectifier is feed from the transformer 81 The machine governor is provided with contacts 83 which close when the machine attains a certain speed, say 80% of full speed. This governor is also provided with contacts 90 which separate when a predetermined overspeed occurs. 9| and 92 are stop buttons located preferably one at the lower landing and one at the upper landing of the stairway. These buttons are arranged in a control circuit common to certain of the operating switches of the stairway, and upon the pressing of either, this circuit is Opened to bring the stairway to a stop. Also arranged in this circuit are the broken handrail switches 34 and 35, previously described, broken chain switches 93 and 94, fire door contacts 95 and service switch 96. Also arranged in this circuit are contacts of overload and reverse phase relays which will be referred to later. I

Th electromagnetic switches have been designated as follows:

B-Brakeswitch BB-Brake relay BD-Down button relay ELI-Up button relay DDelta switch DDDelta relay DR-Direction relay DS-Down direction switch DT--Time relay HD--I-Iandrail down direction switch HOA--Handrail' overload relay HOB-Handrail overload relay HU--Handrail updirection switch OA- Overload relay 01BOverload relay R-Reverse phase relay US-Up direction switch Y-Star switch Throughout the description which follows these letters, in addition to reference numerals, will be applied to parts of the above designated switches. Theelectromagnetic switches are illustrated in deenergized positions. Contacts RI of the reverse phase relay, OAt and OBI of the overload relays and HOAI and HOBI of the handrail overload relays are arranged in the circuit with the safety devices and the stop buttons. Thus, upon occurrence of reverse phase or single phase, or overload on either motor 14 or motor 44, the common control circuit is broken to cause the stopping of the stairway.

The circuits are shown in straight line form, that is, in which circuits are as direct as possible to render them easy to follow. With such diagram, the coils and contacts of the electromagnetic switches are separated. The relationship of these coils and contacts may be seen from Figure 2a. where the switches arearranged in alphabetical order and are shown in spindle form. The coils and contacts are positioned on the spindles in horizontal alignment with the corresponding elements of the wiring diagram. Thus by first locating any coil or contact on the spindle diagram the correspondingelernent on the corresponding wiring diagram may be found.

Assume that it is desired to start the stairway for ascending travel. One of thekey operated switches, say switch 89-, is turned clockwise, completing a circuit forthe coil of up button relay BU. This relay operates to engage contacts Bill, and BUZ. The engagement of contacts BU2: completes a circuit for the coil of up direction switch US, while the. engagement of both contacts BU2. and EU! completes a. circuit for the. coil of brake switch 13,. the lattercircuit extending from. the

U83 and USE in the circuits for the coil of down direction switch DS and the coil of handrail down direction switch HD respectively. It engages contacts USI and U82 to prepare holding circuits for the coils of switches US and B. It also engages contacts US4, completing a circuit for the coil of handrail up direction switch HU. It also engages contacts USS and US! in the circuits for the stator windingsof driving motor l4, the engagement of contacts USS connecting the coil of star switch Y across the supply mains l5 and 16.

Star switch Y and handrail up direction switch l-IU operate simultaneously. Switch Y, separates interlock contacts Y! in the circuit for, the coil of delta switch D. It also engages contacts Y2 and Y3 connecting the stator windings of motor I4 in star relation to the supply mains, the direction of rotation of the rotating field being established by contacts USB and US! for ascending operationoi the stairway. Switch HU separates interlock contacts HUI in the circuit for the coil of handrail down direction switch HD. It also engages contacts HU Z, HU4, HUS and HUT, connecting the stator windings, of motor 44 to the supply mains in star relation. Contacts HU5 and I-IUl establish the star connection while contacts HU2 and HU4 establish a direction of rotation of the rotating field of motor 44 to cause rotation of the motor for ascending movement of the handrails. Brake switch B operates at the same time as switches US, HU and Y to engage contacts BI and complete the circuit for the primary winding of transformer 81, causing the energization of the release electromagnet 82 of the pawl brake. Thus as the motors l4 and 44 are energized, the pawl brake is released, permitting starting of the stairway in ascending op;- eration.

The pawl, upon being released, separates contacts 84 to insert cooling resistance 91 in circuit with the primary winding of transformer 81 and engages contacts 85 to complete a circuit for the coil of brake relay BB. This relay, upon operation, engages'contacts BBI vfurther to prepare holding circuits for the coils of switches B and US. It also separates contactslBBZ and engages contacts BB3, the separation 'of contacts BB2 preventing the establishmentof a circuit through contacts BU2 for the coil of direction relay DR. Relay BB also engages contacts BB4 to prepare a circuit for the coil of delta switch D.

Upon the speed of the motor attaining a certain value, governor switch contacts 88 I close and complete a circuit for the coil of time relay DT. Upon the expiration of a certain time interval, relay DT operates to engage 'its contacts DTI. This completes "a circuit for [the' coil of delta relay DD; RelayDD separates contacts DD2 to deenergize the coil of starswitch Y and engages contacts DD! further to prepare the cir cuit for the coil of delta switch D. Star switch Y upon dropping out separates contacts Y2 and Y3 and engages contacts YI. Contacts Yl connect the coil of delta switch D across supply mains 15 and 16. This switch operates to; engage contacts D4, D and D6 to connect thestator windings of driving motor I 4 in delta relation for a full speed running of the stairway in the ascending direction. Switch D also separates interlock contacts D2 and D3 in the circuits for the coils of direction relay DR and star switchY respectively, contacts D2 'being'provided to prevent energization of the coil of relay DR under conditions where a starting switch is operated to operate down button relay BD after the change of the connections in the stator windings of main driving motor I 4 from star to delta has been effected in starting the stairway in ascending operation. It also engages contacts DI, which completes the holding circuits through contacts USI for the coils of switches B and US, permitting the return of key operated starting switch 80 to neutral position, where the key may be withdrawn.

To start the stairway from rest for descending travel, one of the key operated starting switches, say switch 80, is operated counterclockwise to complete the circuit for the coil of down button relay BD. This relay operates to engage contacts BDI and BD2 to complete a circuit'for the operation is only momentary, however, for the brake relay BB, which operates as a result of the release of the pawl brake and consequent engagement of contacts 85, completes a circuit by the engagement of contacts BB3 for the coil of direction relay DR. Relay DR upon operation separates contacts DRI to break the circuit for circuit for the stator windings of main driving motor l4 and also the circuit for auxiliary motor 44 by causing the dropping out of handrail up direction switch HU. Switch US engages its interlock contacts US3, completing a circuit for T the coil of down direction switch DS. Switch DS engages its contacts D81 and DS8., The engagement of contacts DS! connects the coil of star switch Y across supply mains l4 and 15, causing reoperation of this switch to reconnect the stator windings of the main driving motor im star relation. However, owing to the fact that contacts DS'! and DS8 are closed instead of USB and U31, the direction of rotation of the rotating field of the main driving motor is such as to cause rotation of the driving motor for descending travel ofthe stairway. At the same time, contacts BS6 engage to' complete the circuit for the coil of handrail down direction switch HD, contacts USE being engaged as a result of the dropping out of switch US. Switch HD operates to engage contacts HD3, HD5, HDB, I-ID8 and HD9, connectingthe stator windings of auxiliary motor 44 tothe supply mains in delta relation. Contacts HD3, HD5 and HD9 establish the delta connection while contacts HD6 and HDB establish a direction of rotation of the rotating field of motor 44 to cause rotation of the motor for descending movement of the handrails. The purpose of momentarily starting the stairway in ascending travel when it is desired to have the stairway operate in the descending direction is to effect the release of the pawl brake, the brake descending travel, handrail down direction switch HD separates interlock contacts HDI in the circuit for the coil of handrail up direction switch H11 and down direction switch DS separates interloclccontacts BS3 .and D85 in the circuits for the coils of switches US and EU respectively. Switch. DS also engages .contacts D82 and D84 to prepare self-holding circuits for .the coils of switches Band DS. Also, it separates contacts DSI in the circuit 'for the coils of :DD and DT, preventing the operation of these switches during descending travel of the stairway and thus preventing the dropping out of switch Y and the operation of switch D to change the connections for the stator windings of the main driving motor [4 from star to delta relation. Upon the speed of the stairway attaining.

the value for which governor switch contacts 88 are set, these contacts close, completing holding circuits for the coils of switches B, DR and .DS. Thus the key operated switch may be returned to neutral and the key withdrawn.

When the stairway in operating as a descending one, the difierence between the tension in each handrail at the point where it runs on wheel 24 and the tension at the point where it runs off this wheel is greater than when the stairway is operating as an ascending one.

An auxiliary motor is employed of suffici'entpower to be capable of providing correct torque to drive these wheels under such conditions (in thearrangement illustrated with the motor delta connected). Also, the gearing between the motor and wheels 24 is such as to cause the motor to-run at a certain percentage, say 80%, of synchronous speed to insure sufiicient torque being applied under operating conditions. When the stairway is operating as an ascending one, the greatest difference in tension in the handrails is at the points where the handrails run onto and off the upper newel wheels while the difference in tensionof the handrails at the points where they run onto and off the wheels 24 is relatively small. The auxiliary motor 44 under these conditions may operate star connected as previously described as it is capable of providing sufii-cient torque thus connected to drive wheels 24 during ascending operation. The torque of motor 44 may be further adjusted if desired by means of resistances 10, H and 12, contacts I-IU3, HUG and HUB connecting adjusted portions "of these resistances in circuit with the motor during ascending operation and contacts I-ID2, HD i and HD! connecting adjusted portions of these resistances in circuit with the motor during descending operation; With the wheels 24 driven by a motor separate from the main driving motor, as in the arrangement above described, there is no slippage of the handrails due to a difference in creepage on wheels 24 with respect to that on the newel wheels 22, for the motor 44 acts automatically to drive wheels 24 at a speed which compensates for the difierence in creepage. This is true regardless of whether the stairway is acne-way stairway, i. e., either ascending or descending, or a reversible stair-way. Also, with slippage eliminated, the surfaces of the driven wheels 22 and 24 on each side of the stairway may be of a material, such as rubber, to increase the traction between the handrails and their driven wheels without any undesirable effects. Such construction might be desirable, especially in the case of highrise Stairways.

Although an arrangement has beendescribed as applied to alternating current motors, other motors including direct current motors may be used. When direct current motors are employed the torque of the auxiliary motor mayv be con- Still other arrangements may be provided for permitting relative rotative movement of the driven wheels for a handrail. Also, other forms of control systems may be provided and the invention may be applied to other forms of moving stairway construction.

Therefore, as many apparently widely diiierent embodiments of this invention may be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

What is claimed is:

'1. A moving stairway comprising; a newel wheel; an additional wheel; an endless handrail passing in traction relation around said newel wheel and said additional wheel; driving means for said newel wheel; and driving means for applying torque to said additional wheel and for driving said additional wheel at a speed which varies to compensate for any difierence in creepage of said handrail on said newel wheel and said additional wheel.

2. A moving stairway comprising; an endless handrail; a plurality of wheels around which said a handrail passes in traction relation; a motor for driving one of said wheels; and an additional motor for driving another of said wheels.

3. A moving stairway comprising; a series of steps; an endless handrail; a plurality of wheels around which said handrail passes in traction relation; amotor for driving the stairway; means connecting one of said wheels to said motor to be driven thereby; an auxiliary motor; and means connecting another of said wheels to said auxiliary motor to be driven thereby.

4. A moving stairway comprising; a series of steps; a newel wheel at each end of the stairway; an additional wheel; an endless handrail passing in traction relation around the newel wheels at the ends of the stairway and around said additor; and means connecting said additional wheel to said auxiliary motor to be driven thereby to assist said upper newel wheel in. driving said handrail.

5.,A moving stairway comprising; a series of steps; a newel wheel at, the upper end of the stairway; a newel wheel at the lower end of the stairway; a pair of tensioning wheels at the upper end of the stairway; an endless handrail passing in traction relation around the newel wheels at the ends of the stairway and the ten "sioning wheels between. the upper newel wheel and the lower run or the handrail; means associated with one of,.said .tensioning wheels for [maintaining said handrail taut; a motor for said tensioning wheels to assist in driving said handrail.

6. A moving stairway comprising; a series of steps; a newel wheel at each end of the stairway;

anadditional wheel; an endless handrail passing in traction relation around the newel wheels at the ends of the stairway and around said additional wheel; means for driving the stairway; means for driving said upper newel wheel and said additional wheel to drive said handrail in synchronism with said steps, said last named means including means permitting relative rotative movement of such wheels; and means for controlling the direction of rotation of all of said driving means to cause either ascending or descending operation of said steps and handrail.

7. A moving stairway comprising; a series of steps; a newel wheel at each end of the stairway; an additional wheel; an endless handrail passing in traction relation around the newel wheels at the ends of the stairway and around said additional wheel; a motor for driving the stairway; means connecting the upper newel wheel to said motor to be driven thereby; an auxiliary motor; means connecting said additional wheel to said auxiliary motor to be driven thereby; and means for controlling the direction of rotation of said motors to cause either ascending or descending operation of said steps and handrail.

8. A moving stairway comprising; a series of steps; a newel wheel at the upper end of the stairway; a newel wheel at the lower end of the stairway; an endless handrail passing in traction relation around the newel wheels at the ends of the stairway; means for maintaining said handrail taut, said means including an additional wheel around which said handrail passes in tractionrelation between the upper newel wheel and the lower run of the handrail; a motor for driving the stairway; means for controlling the direction of rotation of said motor to cause either ascending or descending operation of said stairway; means operable by said motor for driving said newel wheel at the upper end of the stairway partially to drive said handrail; an auxiliary motor; means operable'by said auxiliary motor for driving said additional wheel to assist in driving said handrail; and means controlled by said direction controlling means for causing operation of said additional wheel by said auxiliary motor to drive said handrail in the same direction as said upper newel wheel.

9. A moving stairway comprising; a series of steps; a newel wheel at the upper end of the stairway; a newel wheel at the lower end of the stairway; a pair of tensioning wheels at the upper end of the stairway; an endless handrail passing in traction relation around the newel wheels at the ends of the stairway and the tensioning wheels between the upper newel wheel and its lower run; means associated with one of said tensioning wheels for maintaining said handrail taut; a motor for driving the stairway; means for controlling the direction of rotation of said motor to cause either ascending or descending operation of said stairway; means operable by said motor for driving said newel wheel at the upper end of the stairway partially to drive said handrail; an auxiliary motor; means operable by said auxiliary motor for driving the other of said tensioning wheels to assist in driving said handrail; and means for controlling the direction of rotation of said auxiliary motor to cause said other tensioning wheel to drive said handrail in the same direction as said upper newel wheel.

10. A moving stairway comprising; a series of steps; a newel wheel at the upper end of the stairway; a newel wheel at the lower end of the stairway; a pair of tensioning wheels at the upper end of the stairway between the newel wheels; an endless handrail passing in. traction relation around the newel wheels at the ends of the stairway and also around the tensioning wheels between the upper newel wheel and the lower run of the handrail; means associated with one of said tensioning wheels for maintaining said handrail taut; a motor for'driving the stairway; means for controlling the direction 6? rotation of said motor to cause either ascending or descending operation of said stairway; means operable by said motor for driving said newel wheel at the upper end of the stairway; an auxiliary motor; means operable by said auxiliary motor for driving the other-of said tensioning wheels; means controlled by said direction controlling means for controlling the direction of rotation of said auxiliary motor to cause said other tensioning wheel to drive said handrail in the same direction as said newel wheel at the upper end of the stairway, said auxiliary motor applying a certain torque to said other tensioning wheel when the stairway is descending; means for decreasing the torque which said auxiliary motor applies to said other tensioning wheel when the stairway is ascending; and additional meansfor adjusting the torque of said auxiliary motor for either descending or ascending operation of the stairway.

11. A moving stairway comprising; a series of steps; a newel wheel at the upper end of the stairway; a newel wheel at the lower end of the stairway; a pair of tensioning wheels at the upper end of the stairway between the newel wheels; an endless handrail passing in traction relation around the newel wheels at the ends of the stairway and also around the tensioning wheels between the upper newel wheel and the lower run of the handrail; means associated with one of said tensioning wheels for maintaining said handrail taut; a polyphase induction motor for driving the stairway; means for controlling the direction of rotation of said motor to cause either ascending or descending operation of said stairway; means operable by said motor for driving said newel wheel at the upper end of the stairway partially to drive said handrail; an auxiliary polyphase induction motor; means operable by said auxiliary motor for driving the other of said tensioning wheels to assist in driving the handrail; means controlled by said direction controlling means for controlling the direction of rotation of said auxiliary motor to cause said other tensioning wheel to drive said handrail in the same direction as said newel wheel at the upper end of the stairway; means for causing the stator windings of said auxiliary motor to be connected in delta relation when the stairway is descending and in star relation when the stairway is ascending; and a source of polyphase alternating current :for said motors.

DAVID LEONARD LINDQUIST. ARTHUR EDWARD HANDY.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2646868 *Jul 12, 1950Jul 28, 1953Westinghouse Electric CorpMoving stairway handrail control
US7954620Oct 9, 2007Jun 7, 2011Otis Elevator CompanyPassenger conveyor handrail drive control strategy
US7958986 *Dec 21, 2006Jun 14, 2011Otis Elevator CompanyPassenger conveyor handrail drive device
DE3344664A1 *Dec 9, 1983Jul 26, 1984Mitsubishi Electric CorpSicherheitsvorrichtung fuer einen personenfoerderer
Classifications
U.S. Classification198/331, 198/336
International ClassificationB66B23/04, B66B23/00
Cooperative ClassificationB66B23/04
European ClassificationB66B23/04