Abstract:
The present invention teaches a mechanical device that monitors the support wheels, or rollers, of a moving escalator stair step. The diameter of each support wheel is indirectly measured by determining the height of each support wheel axial above a given plane. Support wheels that have unacceptable diameter trip an activation mechanism that sends an electrical signal to stop the escalator&#39;s driving motor.

Description:
RELATED APPLICATIONS 
   This application claims the priority of U.S. Provisional Patent Application Ser. No. 60/548,148 filed on Feb. 26, 2004, titled “Escalator Wheel Monitor.” 

   BACKGROUND OF THE INVENTION 
   The present invention generally relates to people moving escalators and/or other people moving walkways. More particularly the present invention relates to a method and apparatus for detecting and identifying damaged or missing support wheel rollers. 
   Although the embodiment described and taught herein refers to the present invention being used on a rising, or descending, stair escalator, it is to be understood that the present invention may also be used on any closed loop, continuously moving apparatus employing continuously rolling wheels subject to undetected damage and/or ware. 
   Escalators and similar conveyor-type devices, typically incorporate a closed loop, continuous, series of moving platforms, or belts, guided and/or supported upon a closed loop track by rolling wheels or rollers, which move along the closed loop track. Since this type of people mover, or conveyor, operates continuously, the rollers are subject to continuous wear. Because of degradation of the rollers from continuous operational ware, and/or other roller damage, it is necessary to frequently inspect the rollers for operational ware, and/or other types of damage. In addition to scheduled inspections of the rollers, it is desirable to have means to continuously monitor the rollers to detect abnormal wear and/or damage that may occur between scheduled inspections. 
   SUMMARY OF THE INVENTION 
   The present invention teaches a continuously operating mechanical apparatus for detecting supporting rollers, or wheels, of an escalator stair step, which may have experienced undetected operational roller wear, beyond a predetermined limit, unexpected damage to the roller through operational use, or detecting a completely missing roller. 
   The apparatus taught herein comprises a pivoting actuator assembly attached to the return tracks of the escalator. The actuator is mounted directly to the roller track and may be part of the original installation or may be easily retrofitted to existing escalators. 
   The present invention discloses a mechanical apparatus which continually monitors the support rollers of escalators and other similar conveyor devices including means for stopping the escalator when a defective roller is detected. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  presents a pictorial view of an escalator roller monitoring device attached to the return rail, or track, of a typical escalator and embodying the present invention. 
       FIG. 2  presents a reverse image pictorial view of the roller monitoring device illustrated in  FIG. 1 . 
       FIG. 3  presents an exploded pictorial view of the roller monitoring device as illustrated in  FIG. 2  showing the individual elements of the assembly. 
       FIG. 4  presents an exploded perspective of the actuator plate subassembly. 
       FIG. 5  presents a crossectional view taken along line  5 — 5  in  FIG. 1  wherein the escalator roller, passing through the roller monitoring device, exhibits little or no wear. 
       FIG. 6  presents a crossectional view, similar to that of  FIG. 5 , wherein the escalator roller exhibits sufficient wear to activate the roller monitoring device. 
       FIG. 7  presents a schematical elevation view of one side of a typical escalator roller track, or rail, system embodying the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Structural Configuration of the Escalator Roller Monitor. 
     FIG. 1  presents a pictorial view of an escalator stair-step and track assembly  10  embodying a roller monitoring device  15  attached to track  12  and embodying the present invention. Roller monitoring assembly  15  is typically positioned on the return track of the escalator unit&#39;s incline truss. Generally four roller monitoring assemblies  15  are employed on a given escalator unit, one on each of the four return roller tracks as is described further below. 
   Additionally referring to  FIGS. 2 through 5 , roller monitoring assembly  15  basically comprises a mounting plate  16  rigidly affixed to the underside of track  12 . Atop track  12  and opposite mounting plate  16  is a, platform, or ramp,  18 , rigidly affixed atop track  12  as illustrated in the figures. The function and purpose of platform  18  is described further below. Mounting plate  16  and platform  18  may be affixed to track  12  by common fasteners  22  as best illustrated in  FIG. 3 . Mounting plate  16  includes, at opposite lateral ends thereof, downwardly extending bosses  24 A and  24 B. 
   Actuator subassembly  30  comprises a laterally elongated base plate  32  having a pair of rocker arms  34 A and  34 B, affixed to the underside, at opposite ends thereof as best illustrated in  FIG. 4 . Affixed to and extending vertically from rocker arms  34  is a generally, orthogonal actuator cam plate  35  as illustrated in the figures. 
   Actuator subassembly  30  is pivotally connected to mounting plate  16  by way of mounting plate bosses  24 A and  24 B, rocker arms  34 A and  34 B and pivot pins  26 A and  26 B. 
   Two elongate bolts  42 A and  42 B, extend through slots  44 A and  44 B within mounting plate  16 , as illustrated in  FIGS. 1 and 3 , and are affixed to base plate  32  and their associated rocker arm  34 A and  34 B respectively. A compression spring,  46 A and  46 B is positioned on each bolt and between base plate  32  and mounting plate  16  as best illustrated in  FIGS. 1 and 3 . Compression springs  46 A and  46 B act to bias the actuator subassembly  30  in a clockwise direction as viewed in  FIG. 5 . The configuration of actuator subassembly as viewed in  FIG. 5  represents the normal working configuration of actuator subassembly  30 . 
   Affixed to mounting plate  16 , as best illustrated in  FIGS. 1 ,  5  and  6 , is an inductive proximity sensor  48  that senses the proximity, or non proximity, of base plate  32 . Although an inductive proximity sensor is illustrated and described, it is to be understood that any other type of proximity sensor, or limit switch, might also be used. 
   Operation of the Escalator Roller Monitor: 
   Under normal operational conditions, as illustrated in  FIGS. 1 and 5 , escalator support roller  50 , being undamaged and having an acceptable operational diameter D, enters roller monitor assembly  15  by rolling up onto platform  18  whereby axle  52  is elevated above its normal operating elevation above track  12  and passes therethrough. When, as illustrated in  FIG. 5 , roller  50  is of an acceptable diameter D, and has no other physical damage, axle  52 , of roller  50 , passes above actuator cam plate  35  making no contact therewith. 
   However, as illustrated in  FIG. 6 , if support roller  50 ′ has a diameter D′ that is less than that acceptable for further operation, because of operational wear or because of other damage such as a broken or missing roller, axle  52  will not be elevated above its normal operating level above track  12  as illustrated in  FIG. 5  and will therefore engage actuator cam plate  35 , as illustrated in  FIG. 6 , thereby forcing actuator cam plate downward and causing counter clockwise rotation of actuator subassembly  30  about pivot pins  26 , whereby base plate  32 , of actuator subassembly  30 , is moved upward into the sensing range of inductive proximity sensor  48 . Proximity sensor  48  now sends an electronic signal to the escalator controller thereby stopping the escalator until repair of the roller is accomplished. 
   If platform  18  were not present, the possibility would exist that if roller  50 ′ is significantly worn, or if roller  50 ′ is completely missing, escalator step  10  may balance itself upon the three remaining good rollers such that axle  52  would maintain its normal operating elevation above track  12  and clear actuator cam plate  35  and not activate actuator subassembly  30 . To prevent this possibility, platform  18  is provided so that as roller  50 , having an acceptable diameter D, enters the roller monitoring assembly  15 , roller  50 , will be additionally elevated approximately one eight of an inch above track  12  by platform  18 . The height of axle  52  is now being measured as the height above platform  18  and not the height above track  12 . 
   If the diameter of roller  50  is acceptable, axle  52  will be lifted up sufficiently to pass over actuator cam plate  35 . However, if the roller diameter is unacceptable, axle  52  will not be elevated the additional height necessary to clear actuator plate  35  and will thereby engage actuator cam plate  35 . 
   In the event escalator step  10  is balanced upon the remaining three acceptable rollers whereby axle  52  remains at its normal operating height above track  12 , and axle  52  will not be elevated higher, as described above, and thereby axle  52  will, nevertheless, engage actuator cam plate  35  thereby causing inductor proximity sensor  48  to signal the escalator controller to stop the escalator. 
   Turning now to  FIG. 7 , each side of a typical escalator installation includes a step roller track  12  and a step chain roller track  14 . A roller monitor assembly  15  is installed on all four roller tracks. The length L of each roller monitor assembly  15  is dependent upon the operational diameter of the rollers passing therethrough. The length L of monitor assembly  15  should be sufficiently long to permit the roller passing therethrough to, at least, make one full revolution within monitor assembly  15 . Further, monitor assemblies  15 , on each side of the escalator, should be separated by a distance X such that no two rollers are passing through their respective monitors at the same time. 
   It is to be understood that the form of the invention shown and described herein represents a best mode embodiment thereof and that various changes and modifications may be made therein by one of ordinary skill in the art without departing from the spirit or scope of the invention as described and illustrated.