US2096583A

US2096583A - Moving stairway protective device

Info

Publication number: US2096583A
Application number: US126784A
Authority: US
Inventors: Handy Arthur Edward
Original assignee: Otis Elevator Co
Current assignee: Otis Elevator Co
Priority date: 1937-02-20
Filing date: 1937-02-20
Publication date: 1937-10-19
Anticipated expiration: 1954-10-19

Description

Oct. 19, 1937. A. E. HANDY 2,096,583

MOVING STAIRWAY PROTECTIVE DEVICE Filed Feb. 20, 1937 2 Sheets-Sheet l mwkm mvemon WW ATTORNEY Oct. 19, 1937. A. E. HANDY 2,096,583

MOVING STAIRWAY PROTECTIVE DEVICE Filed Feb. 20, 1937 2 Sheets- Sheet 2 v v j 'r j ICl D- Q... L To n L 2 5 ulnuL1- u [L 55 [5,50 &1 54/ I3 flAILAZM H'WINVENTOR m ATTORNEY Patented Oct. 19, 1937 UNITED STATES PATENT OFFIQE MOVING STAIRWAY PROTECTIVE DEVICE Application February 20, 1937, Serial No. 126,784

6 Claims.

The invention relates to protective devices for moving stairways.

Moving stairways are provided with moving handrails for the convenience of persons using the Stairways. These handrails are arranged one on each side of the stairs, and are driven in synchronism with the steps. It has been found desirable to provide a traction drive for the handrails and such drives have been the practice for a considerable number of years. With such a drive it is possible for the handrails to slip with respect to their driving sheaves. It sometimes happens that a handrail does slip due to a force being exerted on the handrail opposite to that exerted to drive it. This force may be an accidental one or one due to the deliberate acts of individuals such as where the handrails are ridden or where one or more persons on the floor adjacent the stairway take hold of the handrail and pull or push back on it. The force exerted may be suificient to stop the handrail or it may only slow it up. In either case, there is relative motion between the steps and the handrail, resulting in a feeling of insecurity on the part of passengers holding the handrail which may cause them to fall. It is desirable, therefore, that the stairway be brought to a stop when such conditions arise. This minimizes the possibility of accidents due to such conditions.

It is the object of the invention to stop the driving of a moving stairway whenever the slow.- ing down or stopping of a handrail occurs. 7

The invention involves the provision of a protective device responsive to the speed of a. handrail for controlling the operation of the driving mechanism for the steps and the handrails to cause the stopping of this mechanism in the event that the speed of the handrail falls below a predetermined value. In carrying out the invention as applied to electric driving mechanism, a speed responsive governor may be provided for each handrail to be driven thereby and arranged with contacts for controlling the supply of electric power to the driving mechanism. Each governor is set to operate its contacts at a handrail speed such that operation of the driving mechanism to drive the steps and the handrails is discontinued when the speed of movement of either handrail falls a certain amount below the speed of step movement.

Features and advantages ofthe invention will become apparent from the following description and appended claims.

In the drawings:-

Figure 1 is a diagrammatic representation in side elevation of a moving stairway embodying the invention; and

Figure 2 is a simplified wiring diagram of circuits for controlling a moving stairway in accordance with the invention.

Referring to Figure 1, the moving stairway ex tends between a lower landing I9 and an upper landing II. It comprises an endless series of steps l2 driven at the upper end of the stairway by means of sprocket wheels through running gear chains, a sprocket wheel and chain being arranged on each side of the stairway. A sprocket wheel and running gear chain are illustrated diagrammatically for one side of the stairway, the sprocket Wheel being designated 13 and the chain I4. The sprocket wheels are mounted on and driven by the main drive shaft l5 of the stairway. This drive shaft, in turn, is driven by an electric motor l6, through reduction gearing l'l, sprocket wheel l3, driving chain 19 and sprocket wheel 20 secured to shaft l5, chain l9 and wheels I8 and 20 also being diagrammatically illustrated.

A machine or stairway'brake is provided for the main drive shaft. A form of brake has been schematically illustrated which acts to stop a descending stairway and to prevent downward movement of an ascending stairway after the supply of power to the driving motor has been discontinued. The brake comprises a disc 2i driven: by the main shaft through spring pressed brake shoes 22 acting as a clutch. Although brake shoes are illustrated cooperating directly with the main shaft, such illustration is for convenience, it being understood that the brake may act directly on driven sprocket 2|]. Associated with the disc is. a ringmember 23 having a plurality of internal pawl teeth 24 for receiving pawl 25. This pawl is biased about a fixed pivot for cooperating with the teeth and is controlled by an electromagnet 21 through link 28 and lever 30. The electromagnet is controlled so as to be energized and deenergized simultaneously with the driving motor. When the electromagnet is energized, the pawl is pulled into position where it is clear of the pawl teeth. This releases the brake, permitting the disc 2| to be freely driven by shaft l5. Upon deenergization of the electromagnet when the stairway is descending, the pawl swings into position to engage the next tooth on ring member 23, bringing the disc to an immediate stop. Thereupon the brake shoes 22 act to exert a braking force on the main shaft to bring the stairway to a stop. Upon deenergization of the electromagnet when the stairway is ascending, the supply of power to the motor being discontinued, the stairway is brought to a stop by forces due to friction, and the brake acts to prevent reversal of the stairway should the load thereon tend to effect such reversal.

The stairway has two endless moving handrails, one at each side thereof, operating at substantially the same speed as the steps. The handrail 3| for one side of the stairway is shown and is diagrammatically illustrated as driven from main drive shaft l5. This is effected by means of a sprocket wheel 32 on the main drive shaft driving sprocket wheels 33 and 34 secured respectively to handrail newel wheel 35 and-handrail return wheel 36 of the tightening mechanism designated generally as 31. There is also pro-' vided a newel wheel 38 for thehandrail at the lower end of the stairway around which the handrail passes. the other side of the stairway is the same. Each of the newel wheels 38 at the lower end of the stairway is arranged to operate a speed responsive device. The speed responsive device for the lower newel wheel shown is illustrated as a gov-' ernor operated switch 40 driven from the newel wheel by means of sprocket wheels 4| and 42 and chain 43. This switch is set so as to close just as the handrail comes up to substantially full running speed and to open again when the handrail falls below this speed. These speed responsive switches are arranged to control the driving motor l6 for the stairwayand the release electromagnet 21 for the stairway brake.

A wiring diagram embodying this control .is shown in Figure 2. It is to be understood that the control may be embodied in any moving stairway control system, a simplified system for a direct current driving motor being illustrated for convenience. No safety devices are included in the wiring diagram. other than the devices responsive to the speed of the handrails. An up starting button, a down starting button and a stop button are provided at each end'of the stairway, preferably located on the face 'of the balustrade as indicated at 44 for the upper end of the stairway and at 45 for the lower end of the stairway. In the wiring diagram the up starting buttons are designated 46 and 41, the down

starting buttons

48 and 50 and the stop buttons 5! and 52. r i

Upon the pressing of either up starting button, coil 53 of the up direction switch U is energized. This switch operates to engage contacts 54 .to energize the release electromagnet 21 of the stairway brake, moving the pawl into position to clear the pawl teeth. The switch also engages

contacts

55 and 55, completing a circuit for the armature 5? of the driving motor IE to start movement of the stairway in the up direction, the motor field 59 being illustrated as connected directly across the supply wires. The up direction switch also engages contacts 58 to prepare a holding circuit. This holding circuit is completed when the stairway comes up to substantially full speed, in the circuits illustrated, by the closing of handrail speed responsive switch 451 for one side of the stairway and the closing of corresponding handrail speed responsive switch 39 for the other side of the stairway. The starting of the moving stairway in the down di rection is effected in a similar manner. by pressing one of the

down starting buttons

48 or 50, down direction switch D being operated instead of up direction switch U. To stop the stairway,

The handrail mechanism forone of the stop buttons 5| or 52 is pressed, breaking the circuit for the coil of the operated direction switch, which drops out to deenergize the release magnet of the stairway brake and disconnect the armature of the driving motor from the supply lines, the brake acting to bring the stairway to a stop if descending and to prevent its reversal after stopping if ascending.

Assume that the stairway is in operation and that, for example, one or more persons at the side of the stairway take hold of the handrail at that side and either pull on the handrail if it be moving away from them or push on it if it be moving toward them. By exerting suflicient force, they may cause the handrail to lose its traction so that it slips with respect to newel wheel 35 and return wheel 36. A similar condition may arise when the handrail of an ascending stairway is ridden, the force due to the weight of the person or persons on the handrail which acts against the driving force being augmented by the increased friction between the handrail and the balustrading. This condition may arise from other causes, such as something becoming jammed between the handrail and the balustrade in the opening in the balustrade to receive the handrail. These various situations are known tohave arisen.

Slipping of the handrail on its driving sheaves may only slow it down or it may bring it to a stop, depending upon the amount of the force exerted in opposition to the driving force. In any event, the lower newel wheel 38, being driven by the handrail, accurately registers its speed and this registration is transmitted to speed

responsive switch

39 or 40. Thus, whenever an appreciable decrease in the speed of either handrail takes place, the speed responsive switch for that handrail opens to break the circuit for the coil of the operated direction switch, whereupon the stairway is brought to a stop. Thus, the possibility of accidents due to a change in the speed of either handrail with respect to the speed of the steps is minimized.

It is to be understood that any form of speed responsive device may be utilized, the arrangement shown being intended to illustrate diagrammatically a form of device which may be utilized. Also, the positioning of the speed responsive devices and the manner in which they are driven maybe arranged to suit the particular installation, any arrangement which will register a de-' crease in the speed of either handrail with respect to that of the steps being satisfactory. Various details of the moving stairway may be changed. For example, a form of brake may be provided which acts to exert a braking action to stop the stairway. when either descending or ascending. Also, the invention may be applied to other forms of moving stairway construction, the form shown being chosen for convenience of illustration.

Therefore, as many apparently widely difierent 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 series of steps, a handrail, mechanism for driving said steps and handrail in synchronism, and means responsive to a decrease in speed of the handrail below that of the steps for bringing said steps and the handrail to a stop.

2. A moving stairway comprising, a series of steps, a handrail, mechanism for driving said steps and handrail in synchronism, and means responsive to the speed of the handrail for bringing said steps and the handrail to a stopwhen the speed of the handrail falls below that of the steps.

3. A moving stairway comprising, a series of steps, a handrail, mechanism for conjointly driving said steps and handrail, and means responsive to the speed of the handrail for bringing said driving mechanism to a stop upon the slowing down or stopping of the handrail.

4. A moving stairway comprising, a series of steps, a handrail, mechanism for moving said steps and handrail conjointly, an electric motor for driving said mechanism, a source of current for said motor, switching means for connecting said motor to said source, and means responsive to the speed of the handrail for causing operation of said switching means, upon the slowing down or stopping of the handrail, to disconnect said motor from said source and bring said mechanism to a stop.

5. A moving stairway comprising, a series of steps, a handrail having a newel wheel at the upper and lower ends of the stairway, mechanism for moving said steps and handrail conjointly, an electric motor for driving said mechanism, a source of current for said motor, switching means for connecting said motor to said source, and speed responsive means driven by one of said handrail newel wheels for causing operation of said switching means, when the speed of the handrail falls below that of the steps, to disconnect said motor from said source.

6. A moving stairway comprising, a series of steps, a pair of handrails, one on each side of the stairway, each handrail extending around a newel wheel at the upper and lower ends of the stairway, mechanism for moving said steps and handrail conjointly, said mechanism in moving said handrails operating through the newel wheels at the upper end of the stairway, an electric motor for driving said mechanism, a source of current for said motor, switching means for connecting said motor to said source, and a device for each handrail responsive to the speed thereof, each device being driven by the newel wheel at the lower end of the stairway for the handrail for which the device is provided and acting, when the speed of such handrail falls below that of the steps, to cause operation of said switching means to disconnect said motor from said source.

' ARTHUR EDWARD HANDY.