Abstract:
A hanger connects an enclosed track rail to a beam such that the enclosed track rail is positioned laterally with respect to the beam. The hanger and the arrangement of the track rail with respect to the beam allows rapid conversion of a material handling system from “open roller” tracks to enclosed tracks without removal of existing tracks, without adding new structural support for the enclosed tracks, and without substantial reduction in overhead clearance. A method of retrofitting an enclosed track rail to a material handling system having an open-roller track is also provide.

Description:
TECHNICAL FIELD 
     This invention relates to material handling system arrangements wherein an enclosed track rail is mounted laterally with respect to a beam. 
     BACKGROUND OF THE INVENTION 
     Prior art material handling systems include an overhead beam, such as an I-beam or a similar beam. A lower flange of the beam functions as a track on which the rollers of a trolley are engaged so that the trolley is translatable along the beam. The trolley is operatively connected to a load-carrying apparatus, such as a hoist or a block and tackle apparatus, to facilitate the transportation of heavy or cumbersome objects. 
     These prior art systems are sometimes described as “open-track” or “open-roller” because the flange of the beam, i.e., the track on which the trolley wheels are engaged, is exposed to the environment. The accumulation of dust and debris on the track may cause considerable resistance to the trolley rollers during trolley translation along the track. The resistance may be particularly problematic if the trolley is propelled manually. To alleviate this problem, newer material handling systems often employ enclosed track rails, in which a track and passage for a trolley are enclosed and therefore protected from the environment. The new enclosed track rails result in less resistance to the movement of the trolley, and have fewer maintenance requirements, than the prior art open-roller tracks. It is therefore desirable to replace open-roller tracks with enclosed track rails. 
     To avoid the cost of removing existing open-track beams and installing new support structure for new enclosed track rail, enclosed track rail is sometimes retrofitted to existing material handling systems by suspending the new track rail below an existing open-track beam with a hanger connected to the lower flange of the beam. However, retrofitting a material handling system by suspending an enclosed track rail from an existing beam substantially increases the vertical dimension of the material handling system, which correspondingly decreases overhead clearance beneath the material handling system. This problem is particularly acute where an existing beam is in a low-clearance area; in this instance, suspension of an enclosed track rail below the beam may be impractical or impossible because the enclosed track rail would be excessively low. Substantial cost must then be incurred in removing the existing beams and installing new support structure for the enclosed track rail. 
     SUMMARY OF THE INVENTION 
     A hanger for mounting an enclosed track rail to a beam is provided. The hanger includes at least one structural member to which the enclosed track rail is operatively connectable, and a fastening element adapted to connect the structural member to the beam. The hanger is configured so that at least a portion of the structural member projects sufficiently outwardly from the beam to enable at least a portion of the enclosed track rail to be laterally positioned with respect to the beam. 
     A material handling system arrangement is also provided. The material handling system comprises a rail at least partially defining a passage, a track within the passage, a beam, and a hanger operatively connecting the rail to the beam such that at least a portion of the rail is positioned laterally with respect to the beam. A corresponding method is also provided. The method includes connecting an enclosed track rail to a horizontally-oriented beam such that at least a portion of the rail is positioned laterally with respect to the beam. 
     The invention enables rapid conversion of “open roller” track systems to enclosed track systems with little or no loss of overhead space and without the expense and time involved in removing existing beams and installing new support structure. 
     The above features and advantages, and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic sectional side view of a material handling system arrangement including a beam, an enclosed track rail, and a hanger; 
         FIG. 2  is a schematic sectional side view of the material handling system arrangement of  FIG. 1  employing an alternative hanger configuration; and 
         FIG. 3  is a schematic front view of the material handling system of  FIG. 2 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIG. 1 , a material handling system  10  is schematically depicted. The material handling system  10  includes a horizontally oriented open-track I-beam  12  and is retrofitted to include an enclosed track rail  14  parallel to the I-beam. The I-beam  12  includes an upper flange  18 , a lower flange  20 , and a web  22  interconnecting the upper flange and the lower flange. The upper flange  18  and the lower flange  20  are substantially horizontally oriented, and the web  22  is substantially vertically oriented. The upper flange  18  is characterized by an upper surface  24  and a lower surface  26 . The lower surface  26  is substantially bisected by the web  22 . In the context of the present invention, an “I-beam” includes beams having an upper flange and a lower flange interconnected by a web; the upper flange may or may not have a different size or shape than the lower flange. 
     The enclosed track rail  14  forms a partially-enclosed passage  28  in which a trolley  30  is partially located. The rail  14  defines two surfaces  32  forming a track  34  on which rollers  36  of the trolley  30  are rollingly engaged for translation of the trolley  30  along the rail  14 . The rail  14  may, for example, be part of a monorail system, a runway for a bridge crane system, etc. In the situation where the rail  14  is a runway for a bridge crane system, the trolley  30  will be attached to a support  37  for a bridge rail (not shown) to form an end truck  38 . The rail  14  is mounted to the I-beam  12  via a hanger  39 . 
     The hanger  39  supports the rail  14  from the I-beam  12  such that at least a portion of the rail  14  is positioned laterally with respect to the I-beam  12 . In other words, the rail  14  is positioned such that at least a portion of the rail  14  extends alongside the I-beam  12 . More specifically, at least a portion of the rail  14 , including at least a portion of the passage  28 , is positioned higher than the lower surface  40  of the I-beam  12 . 
     The hanger  39  includes a first fastening element  42  that connects the hanger  39  to the upper flange  18  by contacting the lower surface  26  of the upper flange  18  on a side of the web  22  different from the side of the web  22  on which the rail  14  is located. The fastening element  42  in the embodiment depicted is an integral curved extension of a structural member  44  that forms a hook. However, those skilled in the art will recognize a variety of fastening elements that may be employed to connect the hanger to the beam within the scope of the claimed invention. 
     The hanger  39  includes a second fastening element  46  that connects the rail  14  to the hanger  39 . In the embodiment depicted, the second fastening element  46  includes a hole  48  through which a threaded rod  50  extends. The threaded rod  50  is held in place by a plurality of nuts  52 . The height at which the rail  14  is suspended is adjustable by adjusting the position of the rod  50  with respect to the structural member  44 . The rod may be mounted at one of its ends to the rail  14  by welding, a clinch nut, etc. 
     The structural member  44  has a cantilever portion  56  between the first fastening element  42  and the second fastening element  46 . The cantilever portion  56  projects outwardly from, i.e., away from, the I-beam  12  and transmits loads between the rail  14  and the I-beam  12 . Welds  58  may be employed to further affix the hanger  39  to the I-beam  12 . 
     Referring to  FIGS. 2 and 3 , wherein like reference numbers refer to like components from  FIG. 1 , a material handling system  10 ′ employing an alternative hanger  39 ′ is schematically depicted. The hanger  39 ′ includes two U-shaped members  60  spaced a distance apart from one another and extending transversely across the upper surface  24  of the upper flange  18 . Each of the two members  60  has two clamps  64  that connect the member  60  to the upper flange  18 . 
     Each clamp  64  includes a lower member  72  that contacts the lower surface  26  of the upper flange  18 , a bolt  76  that extends through an elongated slot  80  on one of the members  60  and a hole (not shown) in the lower member  72 , and a nut  88  that engages the bolt  76  so that the bolt provides a compressive force to member  60  and the lower member  72 . For each member  60 , one clamp  64  is located on the same side of the web  22  as the rail  14  and one clamp  64  is on the opposite side of the web  22 . Washers  92  are preferably used between the bolt head and the member  60 , and between the nut  88  and the lower member  72 . The bolts  76  are movable within the slots  80  so that the clamps  64  are adjustable to fit I-beams of various sizes. Those skilled in the art may find it preferable to employ elongated slots, rather than circular bolt holes, on other hanger components in order to provide flexibility in the relative placement of hanger components with respect to one another. Alternatively, multiple circular bolt holes through which a bolt may extend, rather than a single bolt hole, may be employed to provide flexibility in the relative placement of hanger components with respect to one another. 
     An L-shaped bracket  96  has an upright portion  100  and a horizontal portion  104 . The horizontal portion  104  includes elongated slots (not shown) through which the bolts  76  of two clamps  64  extend so that the L-shaped bracket  96  is secured to the members  60 . A plate  108  and a vertically-oriented support member  112  are attached to the upright portion  100  by bolts  76  such that the plate  108  is between the upright portion  100  and the vertical support member  112 . 
     At least a portion of some of the structural members, including members  60 , the L-shaped bracket  96 , the plate  108 , and the vertical support member  112 , form a cantilever portion  56 ′ of the hanger  39 ′. A rail attachment  116  fastens the rail  14  to the cantilever portion  56 ′ at the vertically oriented support member  112 . The cantilever portion  56 ′ extends sufficiently outwardly from the I-beam  12  to enable at least a portion of the rail  14  to be positioned laterally with respect to the I-beam. 
     While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.