US1610428A

US1610428A - Safety device for escalators

Info

Publication number: US1610428A
Application number: US585955A
Authority: US
Inventors: Wilfrid A Daly; Samuel G Margles
Original assignee: Otis Elevator Co
Current assignee: Otis Elevator Co
Priority date: 1922-08-30
Filing date: 1922-08-30
Publication date: 1926-12-14
Anticipated expiration: 1943-12-14

Description

Dec. 14 1926. 1,616,428

w. A. DALY ET AL SAFETY DEVICE FOR ESCALATORS Filed Augist 30, 192,1 2 Sheets-Sheet l A75 wuemtow Dec. 14 1926. 1,610,428

w. A. DALY ET AL SAFETY DEVICE FOR ESCALATORS Filed August 30. 1922 2 Sheets-Sheet 2 WEI A2 jL/l Patented Dec, 14, 1926.

UNITED STATES A 1,610,428 PATENT OFFICE.

WILIERIIiD A. DALY, OF YOINKERS, AND SAMUEL G. MARGLES, OE BROOKLYN, NEW YORK, ASSIG'NORS TO OTIS ELEVATORCOMPANY, OF JERSEY CITY, NEW JERSEY, A

CORPORATION OF NEW JERSEY.

SAFETY DEVICE FOR ESCALATORS.

Application filed August Our invention relates particularly to ceritain improvements in escalators which employ endless chains to which the steps, cleats or tread sections of the escalator are attached and move them along on or in ways or tracks designed for that purpose. It is held in the practical arf'that it is important to provide escalators with a suitable emergency safety device which in case of the breaking of the chains will effect and insure the safe and proper stopping of the escalator, preferably substantially the whole escalator and virtually immediately or actually at once upon the breaking of a chain. In that type of escalator or inclined conveyer in which two chains are employed, and to which the moving steps areattached, the chains are usually placed apart from each other a considerable distance, depending upon the width of the steps measured from end toend. In the type of escalator in which our invention is more especially designed to be used the two chains are spaced apart from each other a-pproximately the width of the steps or cleats,

and are attached to the upper front carriers of each step, and carry wheels upon which =ne steps and chains roll along. In considering the safety features to be provided with such type of escalator. it is important that a suitable safety device shall be provided. which will act to cut or shut off the power from the driving machine and apply they" brake to the escalator and cause the immei. =diate stopping of the whole escalator, should either of the chainsbreak in two from any cause. Should one chain be broken, and the other chain remain intact, it is clear that the broken'chain will allow that side of all of the steps following to sag back thereby throwing great stress on the unbroken chain," and possibly, if not probably, causing the steps to assume a skewed position or conditioir'and jam in the guides in the escalator with resulting damage to the structure and possible injury to the passengers. Any device to afford protection in such a case ofaccident and which will act to cause immediate stopping of the escalator must have an actuating mechanism which will be instantly affected to functionby any change in speed. and consequently-the relative positions, of the two chains; in other words, such an actuating device must be instantly affected by any difference in speed of the two chains; in

, 1922. Serial No. 585,955.

brief, it must possess, among other qualities, the attribute of a differential device. It is the object of our invention to provide a safety device possessing the characteristics tached to chains, with our invention combined with the escalator.

Figure 2 is a more or less detail and assembly illustration of our safety device, taken on theline 2-2 of Figure 3, with a switch shown therein in elevation, in and with an escalator.

'Figure 8 is an end view in assembly of type, having steps 1, or cleats, or other form pf tread or carrying sections, designed to constitute a movable tread platform or surface adapted to be inclined fand connect two different floor levels (not shown) The steps are attached at-the opposite sides of their front ends to two endless driving chains, 2, running parallel to each other at the sides of the escalator, andcarrying wheels, 3, upon which the straps and chains move along.

The track rails, 4, are suitably arranged or laid in 'a well known manner to constitute the horizontal and incline runs for and between the floor landings of the escalator, the rails constituting an upper and lower run for the steps. The two endless chains, 2, are arranged on a center line coinciding with the center line of two sprocket Wheels, 5, one sprocket wheel only being seen on the figures, The driving chains, 2, in the present illustrations comprise a series of links, 6, ivotally connected to the front wheel axles, adapted to form endless chains. The chains pass around the sprocket wheels, 5, and may be driven by any suitable power, an electric shaft. 29 for both sprocket. wheels.

motor, 8, for example, as, illustrated in Figure 1.

Coming now to a more particular description of our safety device invention, in the forms illustrated herein, it may consist. as shown in Figures 2 and 3,01 two thin idling sprocket wheels, 9, with'teeth, '10, to fit the escalator chains, 2; each idling sprocket, 9, is driven by its escalator step chain. 2. In the normal operation of the escalator the two chains travel exactly at one and the same speed, therefore the two idler sprockets, 9, will rotate at one and the same speed with each other. If, however, any difference in speed of the two chains occurs. the two idler sprockets will be rotated at different speeds from each other. One idler sprocket 9 is attached to a curved arm 11 on a shaft 24 common to both sprocket wheels and the arm is so arranged that unless equal speedof rotation of the two sprockets is maintained the dilference in their relative speeds of rotation will cause the arm 11 by a roller 12 afiixed thereto to move out of a recess 13, on another suitable member 14 and move the said member in the operation. The member 14 in turn moves a bolt 15 held by an arm 16 hinged at 17 to'jan electrical switch 18 to trip a trigger 19 of the switch, breaking the electrical connection between contacts 20 of the switch. To accomplish this the trigger 19 is pivotally mounted at one end on pin 51 and provided with a. notch 52 at the end of a projection 53. Arm 16 is provided with p a latch 54 which. in the normal position as shown in Fig. 2, engages with notch. 52.

Upon movement of-bolt 15 and consequently arm 16 about hinge point 17, latch 54 is movedou't of notch 52, thereby permitting trigger 19 to drop and pivotabout pin 51 to open contacts 20. The action of the member 11 is against springs 21 and bolts 22 in the member and fastened to a V grooved drum 23 pinned to the shaft of the safety device. The contacts 20 in opening are adapted to break the circuit to a winding- 25 of a motor switch B shown in Figure 1 and. the switch in becoming deen'ergized will, by its then open contacts 26, open the circuit to the escalator driving motor 8 and stop it and the escalator.

Our differential safety device. so to speak. is shown in another form in Figures 4 and 5. The two thin idling sprocket wheels 9 in Figure 4 anddescrihed in connection with Figures 2 and 3 have teeth to fit the escalator chain 2, and each is driven by its escalator step chain 2. In the present figures a hub 2T to which one sprocket wheel is' attached is keyed by a. key 28 to a common The other sprocket wheel 9 is fastened to a hub 30 that is loose on the shaft 29. The hub 30 has slots 31 therein as seen in Figure 5.

A member 32, also keyed to the shaft 29 by akey 33, has fingers 34 formed thereon and is held to the hub by the fingers engaging; the hubs full parts. 'Since the member 32 and one sprocket wheel 9 by its-hub 27 is keyed to the shaft 29 of the device they will at all times rotate at the same speed, and also the other sprocket wheel 9 under normal conditions. Should the speed of the sprocketwheel 9 on the hub 30 become different than that of the other sprocket wheel 9 and member 32, the fingers 34 on the memher 32 will move over the surface of the full parts of the hub between its slots 31 until the slots are reached at which time the fingers will slip through the slots by the action of a spring 35 between the hub and member 32 and cause the said member to move a bolt 36 held by an arm 37 hinged at 38 to an electrical switch 39, and cause the motor 8 and the escalator to be stopped as told before with Figures2 and 3.

Our safety device invention is also for stopping an escalator of the ascending type immediately upon it being caused to reverse to a direction of travel that is other than its normal direction. With the above object in view the device comprises a pair of arms 40, each having an inverted V-shaped hearins: surface and held together and to the V groove drum 23 by a pair of rods 41. The rods have springs 42 thereon to keep the arms to the drum to take up the wear since the drum rotates with the shaft 24 to which I it is pinned by a pin 43 and with the sprocket wheels 9 when they are operated by the escalator. One arm 40 has a finger 44 formed thereon which holds a trigger 45 of an electrical switch 46 and the trigger holds a pair of contacts 47 of the switch in electrical connection with each other. A projection- 48 also formed on the same arm 40 is adapted to abut against a bolt 49 held by a plate 50 fastened to the escalator frame work and which holds both. arms 40 from turning, Should the escalator be cau ed to reverse to a down direction of travel the finger 44 will leave the trigger 45 which will drop down and break the electrical connection between the contacts 47 of the switch and cause the escalator driving motor 8 to be stopped. As shown in Figure 1 the switch 46 is in common with the other switch 18 of the device, each in being opened causing the escalator motor to be stopped.

One skilled in the art may make obvious vice comprising the combination of members adapted upon the breaking of a chain to engage said chainsmeans to control the operating power for the chains, adapted to be operated by said engaged members to effect the interruption of the power for the chains.

3. In the art of conveyers having transporting chains, adapted to be operated by an electric motor, a safety device comprising the combination of members one ofwhich is adapted upon the breaking of a transporting chain to be operated by an 111- tact chain, a switch adapted to be operated by said member upon the breaking of a chain and effect the stopping of the motor.

4. In an endless conveyer having transporting chains adapted to be operated by an electric motor, a safety device for stopping the motor in case of the breaking of a transporting chain, comprising the combination of movable members adapted in the normal operation of the conveyer to benmoved together by said-chains and upon the breaking of a chain to be differentially moved. a switch adapted to be operated upon the differential movement of said members and interrupt the power to then'iotor.

5. In the art of power driven mclinedcon-,

veyers of the escalator type of endless stepforimn'g sections, the combination of the step-carrying chains, and a safety device for effecting the stopping of the escalator in case of the breaking of a chain. said device comprising wheels adapted in the normal operation of the escalator to rotate at the same speed, but upon the breaking of a chain to rotate at a differential speed, and ower cut-out means adapted to be operatec as a consequence of said difference in speed, to

cause the interruption of the driving-power.

for the escalator;

6. In the'art of emergency safety devices for escalators, having steps-carrying chains, adapted to be driven by an electric power apparatus, a safety device comprised of Wheels driven by said chain and adapted upon the breaking of a chain to be rotated at a differential speed, and amember controlling the power apparatus for the es calator adapted to operate and interrupt the operation of said power apparatus, as a consequence of said differential speed, thereby allowing the escalator to stop.

7 In the art of emergency safety devices for escalators, having steps-carrying chains, adapted to be driven by an electric motor, an electric contact to control said motor, a safety device comprised of members driven upon the breaking of a chain at a differential speed, arms to whiclrsaid members are attached, a normally locked member, adapted to be released as a consequence of said differential speed, and thereby open Said contact and allow the escalator to stop.

8. In an escalator having a driving chain and motive means for normally driving said chain in. one direction, a controlling device having an on position and an off position, said device, when in its on position, permitting the supply of power to said motive means, and, upon being released to off position, causing the discontinuance of the supply of power to said motive means, a member driven by said chain, and mechanism frictionally engaging said member to maintain said controlling device'in its on position when the chain is being driven in said one 'direction, saidmechanism being operated by said member to release said controlling device to its off position upon a reversal of the direction of'motion of said chain, regardless of the cause of the reversal.

9. In the art of emergency safety devices for inclined ascending conveyers, adapted to be driven by an electric motor, a closed electric switch to control said motor, a safety device comprising a rotatable drum, pressure members on'the drum adapted to turn when the conveyer is accidentally reversed, one of the said members having a finger adapted to open said switch as a consequence of the reversal of the conveyer and allow the conveyer to stop.

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

WILFRID A. DALY. SAMUEL e. MA'RGLES.