Abstract:
A passenger conveyor assembly including a roller assembly having an axle member, a bearing member mounted to the axle member, and a roller member rotatably mounted to the bearing member. A seal assembly is mounted to the roller assembly. The seal assembly includes a rotating member mounted for rotation with the roller member and a stationary member fixedly mounted relative to axel member. The rotating member and stationary member cooperate to substantially prevent foreign objects from accumulating at one of the bearing member and the axle member.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a National Stage Application of PCT Application No. PCT/US2011/035730 filed May 9, 2011, the disclosure of which is incorporated by reference herein in its entirety. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    Exemplary embodiments pertain to the art of bearing assemblies and, more particularly, to a seal assembly for a bearing assembly. 
         [0003]    Bearings are used in a wide range of application to reduce frictional effects that may occur between two components moving one relative to another. For example, escalators employ a number of bearings to reduce friction that may be generated between rollers and rails as escalator steps travel between floors. Escalators have been used for years to transport people from one level to another in numerous applications. Conventionally, escalators include a plurality of steps that are moved along rails that extend from a first end positioned at a first level or floor and a second end positioned at a second level or floor. The steps include rollers that travel along the rails. The steps are configured to nest one against the other at each of the first and second ends to provide a smooth transition to the first and second floors. Typically, escalators are employed in office buildings, shopping centers, museums, as well as numerous other indoor installations. Escalators are also employed in outdoor locations such as at train stations, metro/subway stations, stadiums and the like. Outdoor installations expose the rollers and associated roller assemblies to foreign objects such as water, dust, other debris and the like. As such, the rollers are provided with seals that are configures to damage to bearings, shafts and the like from foreign objects. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0004]    Disclosed is a passenger conveyor assembly including a roller assembly having an axle member, a bearing member mounted to the axle member, and a roller member rotatably mounted to the bearing member. A seal assembly is mounted to the roller assembly. The seal assembly includes a rotating member mounted for rotation with the roller member and a stationary member fixedly mounted relative to axel member. The rotating member and stationary member cooperate to substantially prevent foreign objects from accumulating at one of the bearing member and the axle member. 
         [0005]    Also disclosed is a seal assembly including a rotating member configured and disposed to be mounted for rotation with a roller member, and a stationary member configured and disposed to be fixedly mounted relative to an axel. The rotating member and stationary member cooperate to substantially prevent foreign objects from contacting one of an associated bearing member and axle member. 
         [0006]    Additionally or alternatively, the invention may include one or more of the following elements in various combinations: 
         [0007]    an annular cavity between a surface section of the rotating member and a surface portion of the stationary member; 
         [0008]    a lubricant substantially filling the annular cavity; 
         [0009]    a high viscosity and low specific weight lubricant; 
         [0010]    a surface section and a surface portion that extend radially and in close axial proximity; and/or 
         [0011]    a conical surface that is formed by the cooperation of the outer circumferential edge portions of the rotating member and the stationary member to direct foreign objects away from an interface of the rotating member and the stationary member. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
           [0013]      FIG. 1  is a perspective view of an escalator step including roller assemblies having a seal assembly in accordance with an exemplary embodiment; 
           [0014]      FIG. 2  is a perspective view of a step roller assembly of  FIG. 1 ; 
           [0015]      FIG. 3  is a cross-sectional side view of the roller assembly of  FIG. 2 ; 
           [0016]      FIG. 4  is a partial perspective view of a rotating member of the seal assembly in accordance with an exemplary embodiment; and 
           [0017]      FIG. 5  is a partial perspective view of a stationary member of the seal assembly in accordance with an exemplary embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
         [0019]    A passenger conveyor assembly, shown in the form of an escalator step assembly in accordance with an exemplary embodiment is indicated generally at  2  in  FIG. 1 . Step assembly  2  includes a step member  4  that is engaged with a pair of step chains  5  (a portion of each of which has been removed to more clearly show step assembly  2 ) and moveably mounted between first and second rails  6  and  7 . First rail  6  includes a step roller track  8  and a step chain roller track  9 . Similarly, second rail  7  includes a step roller track  10  and a step chain roller track  11 . Step member  4 , along with additional step members (not shown) travels between first and second end portions (also not shown) of rails  6  and  7 . Step member  4  includes a tread surface  12  joined to a riser surface  13 . Tread surface  12  includes a first end  14  that extends to a second end  15 . Tread surface  12  also includes a first side  17  that extends to a second side  18 . Riser surface  13  includes a first end portion  30  that extends from second end  15  of tread surface  12  to a second end portion  31 . Riser surface  13  also includes a first side portion  33  and a second side portion  34 . 
         [0020]    Step assembly  2  includes a first step arm  40  that extends between tread surface  12  and riser surface  13 . Step arm  40  includes a first end section  43  that extends to a second end section  44  through an intermediate section  45 . First end section  43  is joined adjacent to first end  14  of tread surface  12  while second end section  44  is joined adjacent to first end portion  30  of riser surface  13 . Step assembly  2  also includes a second step arm (not shown) located oppositely of first step arm  40  that joins tread surface  12  with riser surface  13  between first end  14  and second end portions  31 . Step arm  40  supports a step axle  49  adjacent first end  14  of tread surface  14 . Step axle  49  supports a first step chain roller assembly  53  that travels along rail step chain roller track  9  on first rail  6  and a second step chain roller assembly (not shown) that travels along step chain roller track  11  on second rail  7 . Step arm  40  also supports a step roller assembly  60  adjacent to second end portion  34  of riser surface  13 . Step roller assembly  60  travels along step roller track  8  on first rail  6 . A second step roller assembly  62  that is configured to travel along step roller track  10  on second rail  7  is supported by the second step arm (not shown). Other chain rollers  63  and  64  are also shown in  FIG. 1   
         [0021]    Reference will now be made to  FIGS. 2-3  in describing step roller assembly  60  with an understanding that step roller assembly  62  includes similar structure. Step roller assembly  60  includes an axle member  70 , a bearing member  74  and a roller member  78 . Axle member  70  is mounted in second end section  44  of step arm  40  and includes a first end  84  that extends to a second end  85  through an intermediate portion  86 . Axle member  70  is constrained from shifting axially relative to step arm  40  by first and second clip members  89  and  90 . First clip member  89  is fitted into a first groove (not separately labeled) formed in intermediate portion  86  of axle member  70 . Second clip member  90  is fitted into a second groove (also not separately labeled) arranged at second end  85  of axle member  70 . 
         [0022]    Bearing member  74  is mounted to intermediate portion  86  of axle member  70  between first end  84  and first clip member  89 . Bearing member  74  includes an inner race  96  that is press-fit to axle member  70  and an outer race  97 . Outer race  97  rotates relative to inner race  96  upon a plurality of balls, two of which are shown at  98  and  99 . Bearing member  74  is mounted to axle member  70  to rotatably support roller member  78 . Bearing member  74  also includes first and second bearing seals  104  and  105  that extend between inner and outer races  96  and  97 . Bearing seals  104  and  105  protect bearing  98  and  99  from foreign debris and also can retain any lubricant that may be applied to bearing member  74 . 
         [0023]    Roller member  78  is mounted to bearing member  74 . More specifically, roller member  78  includes an inner hub  110  that receives outer race  97  of bearing member  74 . Inner hub  110  is joined to an outer diametric surface  112  by a plurality of spoke members, one of which is indicated at  114 . Inner hub  110  includes a first annular rim  117  and a second annular rim  118 . First and second annular rims  117  and  118  constrain axial movement of roller member  78  relative to bearing member  74 . A seal assembly  140  is positioned about axle member  74  and covers inner hub  110 . Seal assembly  140  serves to further shield bearing member  74  from foreign debris. Seal assembly  140  includes a rotating member  142  and a stationary member  144  that combine to form an annular cavity  146 . As will become more fully evident below, rotating member  142  is mounted to inner hub  110  and secured to second annular rim  118 . Stationary member  144  is mounted to axle member  70  at the first groove (not separately labeled). 
         [0024]    As best shown in  FIG. 4 , rotating member  142  includes a shield portion  156  having an outer circumferential edge  158  having a first angular surface  159 . Shield portion  156  also includes a first surface portion  160 , a second, opposing surface portion  161 , and an inner diametric edge portion  162  that defines a central opening  163 . Rotating member  142  includes a mounting member  166  that extends axially outwardly relative to shield portion  156  from inner diametric edge portion  160 . Mounting member  166  includes a circumferential lip portion  168 . Circumferential lip portion  168  extends radially inwardly from mounting member  166  into central opening  163 . Circumferential lip portion  168  is configured to engage with second annular rim  118  to secure rotating member  142  to roller member  78 . 
         [0025]    Reference will now follow to  FIG. 5  in describing stationary member  144 . Stationary member  144  includes a shield element  180  including an outer circumferential edge section  182  having a second angled surface  183 . Shield element  180  also includes a first surface section  184 , a second opposing surface section  185 , and an annular tapered portion  187  that extends to an inner diametric edge section  188  that defines a central aperture  189 . Stationary member  144  also includes a mounting element  191  that extends axially outwardly relative shield element  180  from annular tapered portion  187 . Mounting element  191  includes a circumferential lip portion  193  that extends radially outwardly relative to central aperture  189 . Circumferential lip portion  193  is configured to engage with first clip member  89  to secure stationary member  144  to axle member  70 . 
         [0026]    With this arrangement, rotating member  142  and stationary member  144  provide a dual layer of protection for step roller assembly  60 . More specifically, rotating member  142  shields bearing member  74  from foreign debris and/or moisture while stationary member  144  prevents foreign debris and/or moisture collecting at axle member  70 . Moreover, the differential motion of the rotating member  142  relative to stationary member  144  creates a pressure differential. In particular, the axially close proximity of radially extending surface portion  160  and radially extending surface section  184  generates a velocity difference during movement that increases in the radially outward direction. Based on Bernoulli&#39;s Principle, pressure on an outer diameter (not separately labeled) of seal assembly  140  is therefore lower than pressure on an inner diameter (also not separately labeled) of seal assembly  140  created by the velocity difference generated by rotation of rotating member  142 . This pressure differential further inhibits any debris from passing toward the bearing member by urging any foreign matter outward, away from the seal assembly. In addition, annular cavity  146  may be filled with a lubricant, such as grease to still further shield bearing member  74  from foreign debris and/or moisture. Given the pressure gradient created by the rotation of the rotating member  142 , the lubricant may take the form of a low specific weight/high viscosity fluid such as a high viscosity grease in accordance with one aspect of the exemplary embodiment. The additional benefit of using such a lubricant in annular cavity  146  is that any moisture that enters annular cavity  146  will be urged both by the pressure gradient and force of gravity to be expelled from the bottom of the seal assembly. Furthermore, when mounted, first angled surface  159  of rotation member  142  and second angled surface  183  on stationary member  144 . That is, first and second angled surfaces  159  and  183  cooperate to form a conical surface (not separately labeled) that directs moisture away from annular cavity  190 . In this manner, seal assembly  140  serves to enhance an overall operational life of step assembly  2 . It should also be understood that while shown in connection with the step rollers, the seal assembly of the exemplary embodiment could be employed on the rollers supported by the step axle or other chain rollers. Furthermore, it should be understood that while described in connection with an outdoor escalator, the seal assembly could also be provided on escalators designed for indoor use, on moving walks or other forms of passenger conveyors, or on any bearing assembly that requires protection from foreign debris. 
         [0027]    While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims.