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CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/047,617, filed on Apr. 24, 2008, the contents of which are hereby incorporated by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to rolling door assemblies and, more particularly, to axle assemblies for rolling doors. 
       BACKGROUND OF THE INVENTION 
       [0003]    Rolling doors are frequently used in warehouses, industrial and commercial buildings, and other settings. Despite the prevalence of such doors, many of the parts required are specialized, purpose-built parts that can be difficult and expensive to acquire. 
         [0004]    Also, in many rolling door applications, a heavier-duty door is desired or required. For example, a curtain door formed from a plurality of adjoined slats is often employed as a heavy-duty door. Current rolling door designs call for heavy, bulky support systems, such as very heavy axle assemblies, for use in connection with such heavy-duty doors. 
       SUMMARY OF THE INVENTION 
       [0005]    Based on the foregoing, it is an object of the present invention to provide a rolling door assembly that allows the use of more standardized parts, and reduces the weight and complexity of components needed to support the doors. 
         [0006]    According to an embodiment of the present invention, an axle assembly for a rolling door includes an axle, a tube arranged around the axle and adapted for securing a rolling door thereto, and a plurality of stamped sheet metal drums extending between the axle and the tube. 
         [0007]    According to an aspect of the present invention, the tube is formed from roll-formed and butt-welded sheet metal, preferably less than approximately 0.1 inch thick. 
         [0008]    According to a method aspect, a method of making an axle assembly for a rolling door includes roll-forming sheet metal to form a tube, stamping a plurality of sheet metal drums, and arranging the tube and the plurality of sheet metal drums around an axle, such that the drums extend between the axle and the tube. 
         [0009]    According to another embodiment of the present invention, an axle assembly for a rolling door includes an axle, a spiral-wound metal tube arranged around the axle and adapted for securing a rolling door thereto, and a plurality of drums extending between the axle and the tube. 
         [0010]    According to another method aspect, a method of making a rolling door assembly includes spiral winding a tube, connecting the tube to a plurality of drums arranged about an axle, and connecting a curtain to the tube. 
         [0011]    According to further aspects of the present invention, the tube is spiral wound around the axle and drums and the method includes preliminary steps of detaching the curtain from a previous spiral wound tube, and removing the previous tube by detaching the previous tube from the drums and unwinding the previous tube. 
         [0012]    These and other objects, aspects and advantages of the present invention will be better appreciated in view of the drawings and following description of preferred embodiments. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  is an exploded, perspective view, with components partially cut-away to show details, of a rolling door assembly with an axle assembly, according to an embodiment of the present invention; 
           [0014]      FIG. 2  is a sectional view of the axle assembly of  FIG. 1 ; and 
           [0015]      FIG. 3  is an exploded, perspective view, with components partially cut-away to show details, of a rolling door assembly, according to another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0016]    Referring to  FIG. 1 , according to an embodiment of the present invention, a rolling door assembly  10  includes a curtain  12  extending between opposed rails  14 . The rolling door assembly  10  further includes an axle assembly  16  arranged within a housing  20  extending between mounting angles  22 . A drive mechanism  24 , such as a chain hoist, engages one side of the axle assembly  16 . 
         [0017]    The curtain  12  includes a plurality of interlocking slats  30  and a bottom bar  32 . The curtain  12  further includes a plurality of endlocks  34  attached to the slats  30 . The endlocks  34  are slidable within the rails  14  during raising and lowering of the curtain  12 . 
         [0018]    The axle assembly  16  includes a split axle  40  having first and second portions  42 ,  44  coaxially extending from opposite ends of a tube  46 . The tube  46  is advantageously made by roll-forming and butt-welding sheet metal. The thickness of the sheet metal is preferably such that the wall thickness of the resulting tube is less than the schedule  10  thickness for an equivalent-diameter pipe, or less than about 0.1 inch. Attachment blocks  48  are welded to the tube  46 . The top of the curtain  12  is secured to the attachment blocks by, for instance, bolting, such that rotation of the tube  46  is effective to raise or lower the curtain  12 . 
         [0019]    Referring to  FIG. 2 , the axle assembly  16  additionally includes drums  50 ,  52 ,  54  extending between the tube  46  and the axle  40 . The drums  50 ,  52 ,  54  are advantageously formed from stamped sheet metal. The drums  50  are attached to both the tube  46  and the axle  40 , allowing rotational motion imparted to the first portion  42  by the drive mechanism  24  to be transmitted to the tube  46 . The drums  52 ,  54  are attached to the tube  46  and free rotate relative to the second portion  44  of the axle, for example, using bearings  56 . 
         [0020]    Spring cones  58  are connected to the drums  52 . The spring cones  58  connect respective ends of counter-balance springs  60  to the drums  52 . The other ends of the counter-balance springs  60  are attached to the second portion  44  of the axle  40 . The counter-balance springs  60  are configured to counter-balance the weight of the curtain  12 , facilitating raising of the curtain  12 , as well as retention of the curtain  12  in partially and fully raised positions, as will be appreciated by those skilled in the art. 
         [0021]    Referring again to  FIG. 1 , the housing  20  includes a hood  64  and opposing head plates  66 ,  68  attached to respective angles  22 . The tube  46  of the axle assembly  16  is arranged within the housing  20 , such that when the curtain  12  is raised, the curtain  12  rolls up around the tube  46  into the housing  20 . The first and second portions  42 ,  44  extend through respective head plates  66 ,  68 . The driving mechanism  24  is mounted to the head plate  66  and engages the first portion  42  of the axle  40 . 
         [0022]    It will be appreciated that a rolling door assembly according to the foregoing embodiment eliminates the need for a tube formed from a thicker and heavier, and consequently more expensive, pipe material, for instance, the industry standard schedule  40 , while still allowing secure attachment of the curtain  12  with attachment blocks  48 . Additionally, the stamped steel drums  50 ,  52 ,  54  allow for ready integration of commercially available spring cones, bearings and the like into the axle assembly  20 , further reducing manufacturing time and costs. 
         [0023]    Referring to  FIG. 3 , according to another embodiment of the present invention, a rolling door assembly  110  includes a curtain  112  extending between opposed rails  114 . The rolling door assembly  110  further includes an axle assembly  116  extending between mounting brackets  122 . A drive mechanism  124 , such as a chain hoist, engages one side of the axle assembly  116 . 
         [0024]    The curtain  112  includes a plurality of interlocking slats  130  and a bottom bar  132 . The curtain  112  further includes a plurality of endlocks  134  attached to the slats  130 . The endlocks  134  are slidable within the rails  114  during raising and lowering of the curtain  112 . 
         [0025]    The axle assembly  116  includes a single axle  140  that is unrotatably secured to the brackets  122 . A spiral wound tube  146  is arranged around the axle  140 . The curtain  112  is connected directly to the tube  146 . Drums  150 ,  152 ,  154  extend between the axle  140  and the tube  146 . The drums  150 ,  152 ,  154  are connected to the tube  146  and rotatable relative to the axle  140 . 
         [0026]    The driving mechanism  124  engages the drum  150  allowing rotational motion to be imparted to the tube  146  to raise or lower the curtain  112 . Counter-balance springs  160  extend between the drums  150 ,  152  and the axle  140  to offset the weight of the curtain  112 . 
         [0027]    It will be appreciated that a rolling door assembly according to the foregoing embodiment, by employing a spiral wound tube  146 , allows for easier in place replacement of the tube  146  and other components of the axle assembly  116 . For instance, the curtain  112  can be completely lowered and detached from the tube  146 . The axle assembly  116  can then be unwound, removed, and replaced with another assembly. Components internal to the tube  146  can also be readily replaced with the tube  146  removed. 
         [0028]    The present invention is not necessarily limited to the embodiments described herein. Rather, those skilled in the art will appreciate that numerous modifications, and adaptations to particular circumstances, can be made within the scope of the present invention. 
         [0029]    For instance, the present invention is not necessarily limited to a certain type of rolling door, such as the curtain doors shown herein, although features of the present invention are particularly advantageous in connection therewith. Additionally, the present invention is not necessarily limited to a particular type or configuration of curtain, axle assembly, rails, brackets or driving mechanisms. For example, windlocks could be used in lieu of, or in addition to, the endlocks shown. Also, other designs of slats, including insulated slats, could be employed. 
         [0030]    The foregoing is not an exclusive list of modifications or adaptations. Rather, those skilled in the art will understand that these and other modifications and adaptations are possible within the scope of the invention as herein shown and described and of the claims appended hereto.

Summary:
A rolling door assembly includes an axle assembly having an axle extending through a tube to which the door curtain is attached. A plurality of drums extends between the tube and the axle. The cost and weight of the axle assembly can be significantly reduced forming the drums from stamped sheet metal, as well as using relatively thin roll-formed and butt-welded sheet metal to the form the tube. An axle assembly can also include a spiral wound tube that can be readily unwound and replaced with minimal disassembly of the rest of the door assembly.