Abstract:
A skirt panel for a passenger conveyor, particularly an escalator having a plurality of steps. The skirt panel has a plurality of ball bearings that protrude enough from its surface to give a sliding and/or deflecting action to traveling objects so as to reduce skirt panel surface friction and to minimize side of step entrapments. The skirt panel can be fitted for installation as a skirt panel or as an overlay to an already installed skirt panel.

Description:
FIELD OF INVENTION 
     This invention relates to passenger conveyors and, in particular, to a skirt panel for passenger conveyors. 
     BACKGROUND OF INVENTION 
     Passenger conveyors such as escalators and moving walks typically have a frame that supports a passenger moving portion upon which passengers are situated and a drive for causing the moving portion to travel along the frame. The moving portion has a series of steps for the case of an escalator and a flat platform for the case of a moving walk. A pair of balustrades having handrails, skirt panels and balustrade panels is attached to the frame and is substantially vertically disposed on either side of the moving portion. 
     The skirt panel extends along and adjacent the moving portion, for example escalator steps, and extends vertically upward from the treads of the steps. The skirt panel is generally stationary while the escalator steps are in motion. The skirt panel and moving escalator steps are separated by a skirt/step gap that is usually {fraction (1/16)} inch or more, but may be smaller. 
     Passenger injuries have occurred by entrapment in the skirt/step gap of objects such as body parts, clothing or accessories. Body parts that have been entrapped include limbs, fingers, feet, toes, hair and the like. Clothing that has been entrapped includes shoes, shoe laces, draw strings, scarves and the like. Accessories that have been entrapped include pocket books, book bags, back packs and the like. 
     Entrapment occurs as a result of the moving object coming in contact with the stationary skirt panel, being slowed or stopped by the frictional force of the contact and then being forced into the skirt/step gap as the escalator steps continue to move. Entrapment can occur at any point along the skirt/step gap. Any point where entrapment occurs, is known as the pinch point. For example, one point of the skirt/step gap where many entrapments occur is the juncture of the tread of one step and the riser of the next step. Some known skirt panels have deflected away from the moving steps upon heavy contact so that the skirt/step gap and pinch point becomes enlarged, thereby enhancing the chance of an entrapment 
     The entrapment problem has been addressed in several ways. U.S. Pat. No. 5,695,040 discloses an escalator that has a brush or a wiper disposed in the skirt/step gap as a blocking member. Both the brush and the wiper are flexible so that objects that enter the skirt/step gap are still subject to seizure and entrapment. 
     A side-of-step entrapment product, available under the SafetyStrip™ trademark from Adams Elevator Company of Niles, Ill. is a continuous brush that is installed along the length of the skirt panel. The brush is supposed to warn passengers of impending danger when they or their clothing contact it and to present a barrier that must be penetrated to reach the skirt/step gap. This may work for some passengers, but not all. There are some passengers whose limbs (for example, their feet) will miss the brush and contact the skirt panel and be forced into the skirt/step gap. Other passengers will bump hard into the brush, penetrate the brush barrier and contact the skirt panel so as to be exposed to entrapment in the skirt/step gap. Some items of clothing may miss the brush and become entrapped. Other items of clothing that contact the brush may still contact the skirt panel and become entrapped. 
     Another technique has been to coat the skirt panel with a low friction material having a low coefficient of friction (lower than that of stainless steel). However, the materials used have not reduced friction enough to overcome the entrapment problem. 
     An escalator step guidance system, available under the SureGuide™ trademark from Schindler Elevator Corp. of Morristown, N.J. reduces the skirt/step gap size by means of a screw and wiper pad assembly that is mounted below each step tread. Whether the skirt/step gap is {fraction (1/16)} inch, larger or smaller, there is a skirt/step gap in which objects may be entrapped. 
     SUMMARY OF INVENTION 
     An object of the present invention is to provide a new and improved skirt panel for a passenger conveyor. 
     Another object of the present invention is to provide a skirt panel having a surface that causes a moving object to move or slide along the surface and, thus, reduce the effective friction of the surface. 
     Still another object of the present invention is to provide a skirt panel that deflects, bumps or pushes a moving object away from the panel surface. 
     Yet another object of the present invention is to provide a skirt panel that presents a low friction moveable surface to moving objects. 
     The foregoing and other objects are provided in the present invention by a skirt panel having a structure that has a surface facing the moving portion of a passenger conveyor. For the case of an escalator, the moving portion is the escalator steps. One or more moveable elements is mounted in the surface of the skirt panel so as to provide a low friction moveable surface to moving objects. 
     In a preferred embodiments the moveable elements are bearings mounted in the structure so that a portion of each bearing protrudes outwardly from the skirt panel surface so as to provide a sliding action for objects that contact the bearings as the steps travel. 
     The bearings are mounted in holders within the structure. The holders hold the bearings in place and allow the bearings to provide the sliding action. In some preferred embodiments of the present invention, the bearings are ball bearings. 
     The bearings are scattered about the skirt panel surface in an array and are spaced close enough to provide the sliding action and a reduction in surface friction. In some preferred embodiments of the present invention, the array is a honeycomb pattern. 
     In one preferred embodiment of the present invention, the structure includes a first layer whose front surface is the skirt panel surface. This layer has a plurality of apertures through which the bearings protrude. The structure also has a second layer that contains the bearing holders. The second layer is disposed behind the first layer with the bearing holders in registry with the apertures of the first layer. 
     In a preferred embodiment of the present invention, each bearing holder is a cavity that extends through the second layer. A third layer of the structure is disposed behind the second layer for retaining the bearings within the cavities. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     Other and further objects, advantages and features of the present invention will be understood by reference to the following specification in conjunction with the accompanying drawings, in which like reference characters denote like elements of structure and: 
     FIG. 1 is a perspective view of a portion of an escalator; 
     FIG. 2 is a perspective view of a skirt panel in accordance with one preferred embodiment of the present invention; 
     FIG. 3 is a top view of a first layer of the skirt panel of FIG. 2; 
     FIG. 4 is an elevational view of the first layer of FIG. 3; 
     FIG. 5 is a top view of a second layer of the skirt panel of FIG. 2; 
     FIG. 6 is a cross section view along the lines  6 — 6  of FIG. 5; 
     FIG. 7 is a perspective view of another skirt panel embodiment of the present invention; 
     FIG. 8 is a top view of the bearing and plug assembly of FIG. 7; 
     FIG. 9 is a cross sectional view of FIG. 7; 
     FIG. 10 is a cross sectional view of another skirt panel embodiment of the present invention; 
     FIG. 11 is a cross sectional view of yet another skirt panel embodiment of the present invention; and 
     FIG. 12 is a cross sectional view of a further skirt panel embodiment of the present invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     The skirt panel of the present invention is useful in passenger conveyors of all types. However, by way of example and completeness of description, the skirt panel of the present invention will be described herein for escalator type passenger conveyors. 
     Referring to FIG. 1, an escalator  20  is generally represented by numeral  20 . Escalator  20  has a frame  21 , a drive (not shown), a pair of balustrades  22  and a plurality of steps  23 . Each balustrade  22  has a handrail  24 , a balustrade panel  25  and a skirt panel  26 . At the interface of skirt panel  26  and steps  23  is a skirt/step gap that for many current designs is typically about {fraction (1/16)} inch, but may be smaller or larger. 
     Steps  23  are driven by the drive in a generally circuitous path in either the up or down direction. Balustrade panels  22  and skirt panels  26  remain stationary as the steps move. Passenger injuries have occurred by entrapment in the aforementioned skirt/step gap of objects such as body parts, clothing or accessories. The entrapment occurs as a result of the moving object coming in contact with stationary skirt panel  26 , being slowed or stopped by the frictional force of the contact and then being forced into the skirt/step gap as escalator steps  23  continue to move. 
     With reference to FIGS. 2 through 6, there is provided a skirt panel generally represented by numeral  36  according to a preferred embodiment of the present invention. Skirt panel  36  has a structure generally represented by numeral  37 . Structure  37  has first, second, third and fourth layers  38 ,  39 ,  40  and  41 , respectively. First, second, third and fourth layers  38 ,  39 ,  40  and  41  are held together in a sandwich fashion by means of any suitable fastening technique as, for example, by bolts  42  that extend downwardly from first layer  38  through layers  39 ,  40  and  41 . The sandwich structure  37  is secured by nuts (not shown) applied to the screw thread portions of bolts  42 . 
     Structure  37  contains a plurality of moveable elements  43  that provide a low friction moving surface for moving objects that contact any of the moveable elements. Although the moveable elements may be any moveable parts such as belts, rotatable cylinders, disks, plates, panels, balls and the like, the moveable elements are preferably bearings that protrude above or are flush with the top surface  44  of first layer  38 . The bearing protrusions are small enough to fit within the skirt/step gap or can contact the steps. Bearings  43  have one or more directions of rotation and in preferred embodiments are ball bearings that have an infinite number of directions of rotation. 
     Bearings  43  are scattered about top surface  44  in an array that in preferred embodiments is a honeycomb pattern. The spacing of bearings  43  in the array is close enough to impart a sliding and/or deflecting action to moving objects that contact top surface  44  as escalator steps  23  travel by skirt panel  36  so as to provide an effective reduction of surface friction. When such contact is made with bearings  43 , body parts, clothing accessories or other objects can be pulled away with ease and without panic by sliding or deflecting them away and, thus, eliminating frictional force effect, thereby reducing the risk of entrapment. This action also causes a sensation, making a passenger aware of contact with skirt panel  36  that serves as a warning to pull away the object that has made contact. The protruding ball bearings  43  have the effect of reducing the size of the skirt/step gap by the amount of the protrusions of the ball bearings. 
     First layer  38  contains a plurality of apertures  45  through which bearings  43  protrude. Structure  37  contains a plurality of bearing holders  46  arranged in registry with apertures  45  of first layer  38 . Bearing holders  46  are formed by cavities  47  that extend through second layer  39 . Bearings  43  reside in respective cavities  47  bounded at the bottom by third layer  40 . Third layer  40  has a low coefficient friction so as to provide a smooth low friction surface for bearings  43 . Each cavity  47  has a rim portion  48  that is shaped to closely match the bearing contour and dimensioned so as to minimize entry of contaminants into cavities  47  that can cause interference with bearing providing the moving or sliding action. Each rim portion  48  is an annulus that extends upwardly into a corresponding aperture  45  of first layer  38 . 
     Skirt panel  36  is preferably made in modular sections that can be fit together to form an entire skirt panel  26  when installed on an escalator. Alternatively, sections of skirt panels  36  can also be disposed in specific problem areas where contact with moving objects is expected. Skirt panel  36  can be dimensioned to fit over the front or back of an existing skirt panel  26  by means of bolts or other fastening techniques such that the bearing surface is the skirt panel surface. 
     The materials for first, second, third and fourth layers  38 ,  39 ,  40  and  41  are selected to give strength to skirt panel  36  so that it does not deflect away from the steps and widen the skirt/step gap upon contact with an object and to give low coefficient of friction surfaces for bearings  43 . In one embodiment, first and fourth layers  38  and  41  are stainless steel, second layer  39  is an acetyl plastic available under the DELRIN® trademark from A. L. Hyde Company of Grenloch, N.J. and third layer is a plastic available under model UHMW from A. L. Hyde Company. 
     Bearings  43  can be made of any low friction coefficient and durable material such as steel, ceramic or plastic. In the aforementioned embodiment, bearings  43  are stainless steel ball bearings. 
     In some embodiments, the bearings, when spinning and contacting the plastic second and third layers, can emit an audible noise which alerts the passenger to avoid entrapment. 
     Provision can be made for lubricating bearings  43  as, for example, by use of a lubricant impregnated plastic for layers  39  and/or  40  or by use of a lubricating port and channel system (not shown in FIGS. 1 through 6) in structure  37 . 
     FIGS. 7 through 12 show another group of embodiments of the present invention that employ bearing assemblies in the form of plugs that can be plugged into holes closely spaced about a skirt panel either entirely or just in expected problem areas. The plugs can be installed one by one in an installed skirt panel or can be installed in a separate skirt panel section or module that can be placed over the front or back of or replace an installed skirt panel. The protrusions of the ball bearings is low enough to fit in the skirt/step gap. This enables the step sides to pass and even contact the bearings, leaving little or no clearance in the skirt/step gap. 
     In FIGS. 7 through 10, a bearing assembly is generally designated by numeral  60 . Bearing assembly  60  has a plug  61  that is plugged into an aperture  65  in a skirt panel  66 . Plug  61  has a body  62  of durable material such as stainless steel or plastic. In the illustrated embodiments, body  62  is stainless steel and has a cylindrical shape with screw threads  59 . Body  62  contains a plastic bearing holder  63  for bearing  43 . The region  64  is open and contains air. 
     A rim  67  fits within the cylindrical top of body  62 . Rim  67  is designed to the contour of bearing  43  to minimize entry of contaminants into body  62 . Rim  67  has holes  68  that serve as grab holes for plug tightening into the skirt panel as well as lube ports for lubricating bearing  43 . 
     In FIG. 10, plug  61  also has a guard ring  69  that serves as a barrier to entry into bearing holder  63  of debris such as dirt, lint and the like. Bearing holder  63  is constructed of two pieces so as to occupy substantially all of the space within plug body  62 . 
     FIGS. 11 and 12 show another plug type embodiment that has a cylindrical body  72  that has disposed in its bottom  74  an aperture  75 . Body  72  contains a bearing holder  73  for bearing  43 . A portion of bearing  43  extends through aperture  75 . Aperture  75  serves as an exit for debris and allows bearing  43  to roll freely. 
     In FIG. 12, rim  67  has separate lube ports  70  connecting to lube channels  71  that provide lubrication to bearing  43  in body  72  In one design, the channels  71  surround bearing  43 . 
     Although not illustrated, another plug embodiment of the present invention includes a bearing holder structure of the type shown in FIGS. 2 through  6  where the bearing holder is bounded on the bottom by a body with a smooth plastic surface, such as the aforementioned model UHMW. 
     The present invention having been thus described with particular reference to the preferred forms thereof, it will be obvious that various changes and modifications may be made therein without departing from the spirit and scope of the present invention as defined in the appended claims.