Abstract:
A flow shelf roller having an outer circumference, a radially central hub, and an axially central bore forming an inner circumference through the central hub. The inner circumference of each roller has at least one axial relief channel formed therein along the length of the axial bore. In a more particular embodiment, the axial relief channel is formed including a non-perpendicular angle with respect to the inner circumference of the roller. In a more particular embodiment, the axial relief channel includes at least one of an angled chamfer and a radiused corner, adjacent to the inner circumference of the first roller. The disclosure also includes a roller flow shelf including a flow bed roller having any or all of the aforementioned characteristics.

Description:
BACKGROUND 
     1. Field of the Disclosure 
     The present disclosure relates generally to the field of material handling. More specifically, the present disclosure is directed to a wheel for use in a parcel-handling flow shelf device, and a flow shelf including one or more of such wheels. 
     2. Brief Discussion of Related Art 
     A roller bed, or carton flow shelf, for example as marketed by the Assignee of the instant application, is a parcel handling device in which a plurality of wheels or rollers of equal diameter are mounted for rotation around generally aligned axles that are in a common axis plane. Accordingly, a parcel placed on the flow shelf will rest on a transit plane that is offset from the axis plane by the radius of the wheels or rollers, the tangent with the wheels or rollers. 
     Commonly, the wheels or rollers rotate freely around their respective axles. However, in certain instances some or all of the wheels or rollers in a flow shelf may be driven to move parcels. In a free-rotating flow shelf, to transit parcels along the flow shelf the parcel may be pushed, for example by a human operator or a machine. Alternately, the flow shelf may be mounted at an angle relative to horizontal. Thus, the effect of gravity will influence a parcel placed on a high side of the angled flow shelf to transit towards the low side. This gravity feed effect is resisted by friction between the wheels or rollers against their axles, and also by the inertia of the wheels or rollers themselves. 
     In order for a flow shelf to operate with maximum efficiency, the wheels or rollers must roll freely with a minimum of frictional resistance. One expedient solution would be to lubricate the rollers and axles. However, in the real application environment for flow shelf devices, e.g., warehouses, airborne particulate matter are trapped by viscous lubricants. In the long term, lubrication may have a net negative effect on the freedom of wheel or roller motion unless time, labor and expense is incurred for continual cleaning and maintenance. 
     An improved solution for free motion of the rollers compared with the present state of the art therefore remains wanting. 
     SUMMARY 
     In order to overcome these and other drawback, deficiencies and weaknesses in the known art, provided according to the present disclosure is a flow shelf roller having an outer circumference, a radially central hub, and an axially central bore forming an inner circumference through the central hub. The inner circumference of each roller has at least one axial relief channel formed therein along the length of the axial bore. In a more particular embodiment, the axial relief channel is formed including a non-perpendicular angle with respect to the inner circumference of the roller. In a more particular embodiment, the axial relief channel includes at least one of an angled chamfer and a radiused corner, adjacent to the inner circumference of the first roller. 
     In still another embodiment of the present disclosure, the central hub of the first roller has a reduced radial thickness at one axial end thereof. The reduced radial thickness at one end of the central hub may include at least one of an angled chamfer and a radiused corner. 
     In still another embodiment of the present disclosure, the outer circumference of the first roller is crowned, with a diameter of the first roller taken at a point along its axial length being greater than a diameter of the first roller taken at one axial end thereof. In a more particular embodiment of the flow shelf roller according to the present disclosure, the inner circumference of the roller comprises one or more of high-density polyethylene, nylon, polypropylene, polyvinyl chloride, or some combination thereof. 
     In a further embodiment of the present disclosure, provided is a roller flow shelf having first and second support rails, which together define a travel path of the flow shelf. A plurality of axles, each having a first outer diameter, connects the first rail to the second rail, with each axle being generally perpendicular to the travel path of the flow shelf. A plurality of rollers is mounted for rotation on at least one of the plurality of axles, a first roller of the plurality roller of the plurality an outer circumference, a radially central hub, and an axially central bore forming an inner circumference through the central hub. The central bore includes a second inner diameter equal to or greater than the first outer diameter of a corresponding axle on which it is mounted for rotation. Further, the inner circumference of each roller has at least one axial relief channel formed therein along the length of the axial bore. In a more particular embodiment, the axial relief channel includes at least one of an angled chamfer and a radiused corner, adjacent to the inner circumference of the first roller. In other regards, a roller flow shelf according to the present disclosure may include a flow shelf roller having any or all of the aforementioned characteristics. 
     In a more particular embodiment of the present disclosure, a first axle of the plurality of axles has the first roller and a second roller of the plurality of rollers mounted for rotation on the first axle, with a standoff spacer between the first and second rollers. Optionally, the standoff spacer may have a reduced radial thickness at one axial end thereof. In a more particular embodiment, the reduced radial thickness at one end of the standoff spacer includes at least one of an angled chamfer and a radiused corner. 
     These and other purposes, goals and advantages of the present disclosure will become apparent from the following detailed description of example embodiments read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Some embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like reference numerals refer to like structures across the several views, and wherein: 
         FIG. 1  depicts a perspective view of a flow shelf according to one embodiment of the present disclosure; 
         FIG. 2  depicts an overhead plan assembly view of a flow shelf according to the present disclosure; 
         FIG. 3  depicts an assembly view of an axle  16  having a plurality of wheels  18  and spacers  20  mounted thereon; 
         FIG. 4  illustrates in elevation view an embodiment of a flow shelf wheel according to the present disclosure; 
         FIG. 5  illustrates the flow shelf wheel shown in  FIG. 4 , in a cross-sectional view taken along section line  5 - 5  of  FIG. 4 ; 
         FIG. 6A  illustrates a partial detailed view of the central hub of a flow shelf wheel according to one embodiment of the present disclosure; 
         FIG. 6B  illustrates a partial detailed view of the central hub of a flow shelf wheel according to an alternate embodiment of the present disclosure; 
         FIG. 7A  illustrates a partial detailed cross-sectional view of the central hub of a flow shelf wheel according to one embodiment of the present disclosure; and 
         FIG. 7B  illustrates a partial detailed cross-sectional view of the central hub of a flow shelf wheel according to still another embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to  FIGS. 1-3 ,  FIG. 1  depicts a perspective view of a flow shelf, generally  10 .  FIG. 2  depicts an overhead plan assembly view of the flow shelf  10 , including several axles  16  removed for clarity.  FIG. 3  depicts an assembly view of an axle  16  having a plurality of wheels  18  and spacers  20  mounted thereon. 
     A flow shelf  10  includes a frame  12  having two elongated rails  14 . Where the flow shelf  10  had a fixed width along its length, the rails  14  will be parallel with each other. In other cases, the rails  14  may be at an angle to one another, such that the flow shelf  10  becomes wider and/or narrower from one end to the other. The rails  14  may be straight or curved. The rails  14  define a travel path of the flow shelf  10 , along which parcels traverse the flow shelf  10 . The distance between the rails  14  is spanned, and the rails connected by, a plurality of axles  16 . The axles  16  each lie generally in a common axis plane, and at each location along the rails  14 , the axles lie perpendicular to the travel path. The axles  16  support a plurality of rollers or wheels  18  thereon for rotation about the respective axles  16 . 
     Throughout the present disclosure, wheels and rollers may be used generally interchangeably. In practice, the distinction, if any, is that a roller will typically span most or all of the distance between the rails  14 . A wheel  18  will typically be shorter in length. As a result, a flow shelf  10  having wheels  18  may include plural wheels  18  on each axle  16 . See, for example,  FIG. 3 . Multiple wheels  18  sharing the same axle  16  may be separated by a standoff spacer  20  between adjacent wheels. The spacers  20  may be tubular, and placed on or over the axle  16 . Alternately, the spacers  20  need only partially surround the axle, and/or may be fixed to the frame  12  of the flow shelf  10 . Alternately, or additionally, a wheel  18  may be constrained in its position along an axle  16  by a stop  17  embodied as an increase in the diameter of the axle  16 , such that a wheel  18  or a spacer  20  sized to fit closely over the axle  16  is constrained in the axial direction of the axle  16  by the stop  17 . The stop  17  can be formed be a localized expansion of the diameter of the axle  16 , or by, for example applying a welding operation which has the effect to raise a fillet around the circumference of the axle  16 . Alternately, a fastener may be inserted into the axle at a predetermined location to form the stop  17 . In one embodiment of the present disclosure, the axle  16  may be pinched or cinched in order to form a peen that functions as the stop  17 . These embodiments of the axial stop are offered without limitation to any others as may be or become known to those skilled in the art, taken in light of the instant disclosure. 
     More particularly, in the case of multiple wheels  18  on an axle  16 , the wheels  18  may be laterally staggered from one axle  16  to the next, as illustrated in  FIG. 1 . Many implementations are possible within the scope of the present disclosure. 
     Referring now to  FIGS. 4 and 5 , illustrated is an embodiment of a flow shelf wheel  18  according to the present disclosure, with  FIG. 4  showing an elevation view and  FIG. 5  showing a cross-sectional view taken along section line  5 - 5  of  FIG. 4 . The wheel  18  is provided with a central hub  22 , having an inner diameter  24  sized to accommodate a corresponding axle  16 . An outer circumference  26  of the wheel  18  is connected with the hub  22  by a web  28  and/or one or more radial spokes  30 . In more particular embodiments, the outer circumference  26  is crowned in the axial direction of the wheel  18 , such that the wheel  18  and particularly the outer circumference  26  has a greater diameter along a transverse centerline  28  of the wheel  18  and an axial extremity  30 ,  32 . The difference in diameter between the centerline  28  and the axial extremities  30 ,  32  may be modest or great, and moreover the change in diameter may be gradual and rounded, as illustrated in  FIG. 5 , or alternately it may be linear and cone- or peak-shaped, alternately the change in diameter may be stepwise and abrupt. 
     According to an embodiment of the present disclosure, the flow shelf wheel  18  may be constructed such that the outer circumference  26  is longer in the axial dimension of the wheel  18  than the central hub  22 . Alternately, this can be described as the wheel  18  exhibiting recesses  27   a ,  27   b , in either or both ends. More colloquially this arrangement can be called a “bow tie” shape, referring to how the wheel  18  appears in cross-section. The recesses  27   a ,  27   b  can be, but need not be, complementary in size to each other. 
     The inner diameter  24  of the central hub  22  is provided with one or more longitudinal recessed channels  34  therein, extending in an axial direction of the central hub  22 . With reference now to  FIGS. 6A and 6B , illustrated is a partial detail view of the central hub  22  of two respective alternate embodiments. In  FIG. 6A , recessed channels  34  have respective rounded filet  36   a  corners or edges relative to the inner diameter  24 . In  FIG. 6B , recessed channels  34  have corners  36  or edges of the recessed channels  34  provided having an angled chamfer  36   b . This rounding or chamfering also serves to reduce running friction between the axle  16  and the wheel  18 . Both embodiments depicted, e.g.,  FIGS. 6A and 6B  share a characteristic that the recesses are formed including a non-perpendicular angle relative to the inner diameter  24  of the central hub  22 . This is, however, optional, and the recessed channels  34  may be provided with squared edges  36 . 
     To further reduce running friction of the wheel  18 , in certain embodiments the wheel  18 , or at least an inner diameter  24  thereof, is formed including a low-friction material, including without limitation a high-density polyethylene (HDPE), nylon, polypropylene, polyvinyl chloride, or some combination thereof, among other materials. 
     Referring now to  FIGS. 7A and 7B , illustrated are partial detailed view of the central hub of a flow shelf wheel  18  according to particular embodiments of the present disclosure. To still further reduce running friction of the wheel  18 , either or both of axial ends  38 ,  40  of the central hub  22  is crowned by removing material from either a radially inner side  42  and/or a radially outer side  44  thereof. As illustrated in  FIG. 7A , the removal may be in the form of a chamfer  46   a .  FIG. 7B  illustrates the removal in the form of a radius  46   b . Alternately, a step-wise reduction in the radius of the central hub  22  may be used, or some combination of the foregoing. However implemented, the effect is to reduce the contact area of the axial ends  38  and/or  40  of the central hub  22 , where they may touch the axial ends of one or more spacers  20 . 
     Likewise, in a further embodiment, the spacers  20  may also have one or both axial ends  21  thereof crowned from either or both a radially inner and radially outer dimension, for example by chamfer, radius, and/or stepwise reduction, in a like manner as illustrated in  FIGS. 7A, 7B  with respect to central hub  22 . This will have the effect of reducing an area of contact between the spacer end  21  and the hub  22 . Spacers  20 , or at least one or both spacer ends  21  thereof, may be formed including a low-friction material, including without limitation a high-density polyethylene (HDPE), nylon, polypropylene, polyvinyl chloride, or some combination thereof, among other materials 
     Variants of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.