Patent Publication Number: US-7708049-B2

Title: Sheet door system with transition wheels

Description:
BACKGROUND OF THE INVENTION 
     In the art of upward acting doors and flexible closure member or so called rollup type doors, a conventional construction comprises a door which is rolled onto and off of a rotatable drum to provide for moving the door between open and closed positions. In certain applications of rollup doors and, in particular, so called sheet doors, it may be desirable to mount the door and/or ship the door wherein the door rolled onto a drum would be disadvantageous. In low headroom door applications or applications wherein the enclosure or structure using the door is collapsible, a door which is adapted for rolling onto and off of a cylindrical drum would occupy too much space. Accordingly, there has been a need for a flexible type door, or so called sheet door, which may be stored in a generally planar or unrolled condition and moved between open and closed positions without requiring a storage drum or a continuous guide track between a vertical or closed position of the door and a horizontal or open position of the door, for example. It is to these ends that the present invention has been developed. 
     SUMMARY OF THE INVENTION 
     The present invention provides an improved door system, including a flexible door closure member, sometimes referred to in the art as a sheet door. 
     The present invention also provides an improved upward acting door which is moved between open and closed positions on spaced apart guide tracks which include generally linear vertically extending tracks and generally linear horizontally extending tracks and spaced apart transition members are provided which engage the door closure member for guiding the closure member between door open and closed positions. 
     In accordance with one aspect of the present invention an improved upward acting flexible door, or so called sheet door, is provided which is adapted for use with enclosures which have low headroom or enclosures which may be of a type which may be disassembled and collapsed into a stack of substantially flat planar wall, ceiling and floor sections, for example. The improved door system is provided with a flexible sheet-like closure member having parallel undulations or corrugations configured not unlike relatively wide gear teeth and which are engageable with a pair of spaced apart rotatable transition guide wheels which guide the door between generally vertically extending guide tracks and generally horizontally extending guide tracks, respectively. 
     In accordance with another aspect of the invention, a door system is provided for an enclosure wherein spaced apart closure member transition guide wheels are suitably mounted on opposed frame members of the enclosure, which frame members may be disposed in a substantially flat compact stack to provide for more efficient and less space occupying shipping or storage operations. The sheet door system of the present invention is particularly adapted for portable enclosures which may be shipped in a collapsed and generally flat stack of sidewalls, ceiling and floor members, for example. The door system of the invention also provides an advantageous arrangement of a counterbalance shaft and cable drum mechanism for the door closure member. 
     Those skilled in the art will recognize the above-identified advantages and superior features of the invention as well as other important aspects thereof upon reading the detailed description which follows in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a generally rectangular box-like enclosure utilizing the improved sheet door system of the present invention; 
         FIG. 2  is a perspective view illustrating the sheet door support structure, including the door engaging transition guide wheels; 
         FIG. 3  is a view taken generally along the line  3 - 3  of  FIG. 2 ; 
         FIG. 4  is a detail perspective view of one of the transition guide wheels; 
         FIG. 5  is a detail perspective view of the other transition guide wheel for the sheet door system of the present invention; and 
         FIG. 6  is a detail section view taken generally along line  6 - 6  of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     In the description which follows like parts are marked throughout the specification and drawing with the same reference numerals, respectively. The drawing figures are not necessarily to scale and certain elements may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. 
     Referring to  FIG. 1 , there is illustrated a generally rectangular box-like enclosure  10  configured as a portable storage unit having a generally flat ceiling or roof section  12 , opposed sidewalls  14  and  16 , a rear wall  18 , a bottom wall or floor  20  and a minimal front wall  22  providing a generally rectangular opening  24 . Opening  24  is closable by a door system including a flexible closure member or barrier  26 , also known as a sheet door. Those skilled in the art will recognize that, although the sheet door system of the invention is particularly adapted for applications in conjunction with the portable enclosure unit  10 , the sheet door system including the door closure member  26  may be used in many other applications requiring, for example, low headroom and/or storage of the door system in a relatively flat nonrolled condition. The term enclosure herein may also include garages, and similar structures requiring a closable opening suitable for a relatively flexible closure member. 
     Referring now to  FIG. 2 , and also to  FIG. 3 , the enclosure or storage unit  10  is illustrated with the roof or ceiling member  12  removed and the minimal front wall  22  removed to illustrate certain structural features of a door system  28  in accordance with the invention and which includes the flexible closure member or sheet door  26 . Sheet door system  28  includes opposed, somewhat channel shaped, vertically extending guide tracks  30  and  32  which are mounted on respective column members  31  and  33  forming part of the sidewalls or framing for same of the enclosure  10 . Spaced apart generally horizontally extending guide tracks  34  and  36  are aligned with the respective guide tracks  30  and  32  for guiding and supporting the sheet door closure member  26 . Opposite side edges  26   c  and  26   d ,  FIG. 2 , of the sheet door closure member  26  may be slidably disposed in the channel shaped guide tracks  34  and  36  in the open position of the closure member  26 , as shown in  FIG. 2 , which position is disposed at least at an acute angle with respect to the position or plane of the closure member in a closed position. The position of closure member  26  shown in  FIG. 2  may be that suitable for storage or transport of the enclosure  10  in an assembled or disassembled and stacked condition of the enclosure floor, wall and ceiling members. When the closure member  26  is placed in use, the in use door open position may be one where side edges  26   c  and  26   d  adjacent bottom edge  26   b  remain disposed in the upper portions of guide tracks  30  and  32  to provide for maintaining alignment of the closure member with the guide tracks. 
     When the closure member  26  is disposed in a door closed position, as shown in  FIG. 3 , the opposed side edges  26   c  and  26   d  are supported in and guided by guide tracks  30  and  32 , respectively. Guide tracks  34  and  36  are suitably mounted on spaced apart, essentially identical, elongated, parallel, rectangular tubular frame members or beams  38  and  40 , as illustrated. At least one transverse frame member  42  interconnects frame members  38  and  40 . Additional frame members, not shown, may be provided to form the structure of the enclosure  10  and frame members  38  and  40 , preferably, comprise framing for ceiling or roof section  12 , not otherwise shown in  FIGS. 2 and 3 . Moreover, frame members or beams  38  and  40  are also suitably connected to and provide support for planar wall sections  14  and  16 . The column members  31  and  33  are suitably releasably or permanently joined to the frame members  38  and  40 , respectively, and the column members  31  and  33  may also be suitably joined to a floor beam or similar structural member  44 , also as shown in  FIG. 2 . Transverse frame member  42  is adapted to support a counterbalance mechanism, generally designated by the numeral  46 , for counterbalancing the weight of the door closure member  26  when it is moved between an open position, as shown in  FIG. 2  and a closed position as shown in  FIGS. 1 and 3 . Counterbalance mechanism  46  may of a type including an elongated rotatable shaft  48  suitably supported on frame member  42 , spaced apart cable drums  50  suitably secured to the shaft  48  for rotation therewith, and one or more torsion counterbalance springs  52  sleeved over the shaft. Spring  52  is preferably anchored to the shaft  48  at one end of the spring and anchored to a stationary bracket member  54  mounted on the frame member  42  at an opposite of the spring. The torsion spring  52  may be pretensioned in a known way to exert a torque through the cable drums  50  to respective flexible cables  51  wound thereon and connected at their distal ends to the closure member  26 , as also shown in  FIGS. 2 and 3 . The counterbalance mechanism  46  is advantageously mounted on beam  42  and does not project substantially above or below the beam so as to facilitate storage and shipping of the enclosure  10  in a collapsed condition. 
     Referring further to  FIG. 3 , the cross-sectional shape of the flexible closure member  26  is preferably as shown and comprises spaced apart undulations or corrugations  27  having a geometry similar in some respects to spur gear teeth. Closure member  26  may be formed of a continuous sheet of metal or plastic wherein the corrugations or undulations  27  are formed by deforming the material of the sheet closure member or by extruding the sheet closure member of a desired material. Accordingly, closure member  26  may move between the vertical guide tracks  30  and  32  and horizontal guide tracks  34  and  36  and closure member  26  is advantageously guided between such guide tracks by spaced apart transition guide wheels  56  and  58  which are supported in the positions shown in  FIGS. 2 and 3  on the frame members  38  and  40 . 
     As shown in  FIGS. 4 and 5 , guide wheels  56  and  58  may be identical and are preferably formed with circumferentially spaced radially projecting cogs or teeth  57  and  59 , respectively, which cogs or teeth have a geometry essentially corresponding to the undulations or corrugations  27  of the sheet door closure member  26 . In this way, the closure member  26  may be guided more precisely and positively by wheels  56  and  58  when being moved between the open position shown in  FIG. 2  and the closed position shown in  FIG. 3 . 
     As further shown in  FIGS. 4 and 5 , each of guide wheels  56  and  58  is mounted for free rotation on an axle  70  connected to a depending support arm  60  which is mounted for pivotal movement on a support bracket  62 . Each support bracket  62  comprises a somewhat inverted channel shaped member having opposed slots  64  formed in respective flanges  62   a  and  62   b  of the bracket  62 , one slot shown for each bracket, through which a pivot bolt  66  may project and serve as a support shaft for the support arm  60 . Support arm  60  includes a transverse leg  61  having a suitable bore  61   a  formed therein,  FIG. 6 , for receiving the pivot bolt  66 . As further shown in  FIGS. 4 ,  5  and  6 , each support arm  60  includes an upstanding stop leg  63  engageable with an end cap  62   c  of bracket  62  to limit rotation of arm  60  to a substantially vertical position as shown in  FIGS. 4 and 5 . Accordingly, in the working positions shown of the respective guide wheels  56  and  58 , effective guidance of the closure member  26  is provided when the closure member is moved between open and closed positions under, at least partly, the urging of the counterbalance mechanism  46 . A suitable closure member latch bolt and/or handle  26   a ,  FIG. 1 , may be provided on the exterior side of the closure member  26  for locking the closure member in a closed position and for use as a handhold for initial, manual movement of the closure member from a closed position. The closure member  26  may also be grasped at its bottom edge  26   b  to assist in movement thereof. 
     Referring again to  FIGS. 4 and 5 , an advantage of the sheet door system  28  is the provision of the guide wheels  56  and  58  which may be moved between the working positions shown and storage or shipping positions, as indicated by the alternate positions of the wheels in  FIGS. 4 and 5 . Since the respective support arms  60  for the transition guide wheels  56  and  58  may be mounted for pivotal movement between the positions shown in  FIGS. 4 and 5 , the guide wheels may occupy space no greater, essentially, than the transverse height “x”,  FIG. 5 , of the frame members or beams  38  and  40  when in the wheel stored positions, thereby enabling stacking of components of the enclosure  10 , such as the ceiling  12 , sidewalls  14  and  16 , back wall  18 , front wall  22  and floor  20 . This is an advantage in storage and shipping of collapsible storage enclosures, such as the enclosure  10 . In addition to the other advantageous features of the sheet door system  28 , the transition guide wheels  56  and  58  eliminate curved transition track members between the vertical tracks  30  and  32  and horizontal tracks  34  and  36 . Thus, the door system  28  may be stored and shipped in a compact, space saving configuration alone or as part of a collapsible enclosure unit, as described. 
     Referring further to  FIGS. 4 ,  5  and  6 , each support bracket  62  may be permanently secured to the beams  38  and  40 , such as by welding or releasably secured to the beams  38  and  40 . For example, as shown in  FIG. 6 , in particular, a generally rectangular boss  72  may be suitably secured to beam  38 , such as by welding, and have a transverse bore  74  formed therein for receiving a bolt assembly  76 . Boss  72  is configured to receive an open end of channel shaped bracket  62  wherein the opposed flanges  62   a  and  62   b  are provided with fastener receiving bores which are alignable with the bore  74  and each bracket  62  fits snugly on and over a boss  72  and is secured thereto by the bolt assembly  76 . Accordingly, the transition guide wheels  56  and  58 , together with their respective support arms  60  and supporting bracket  62 , may be releasably secured to the beams  38  and  40 , if desired. Still further, the lateral positions of the wheels  56  and  58  may be adjusted by placing the support arms  60  in a desired position within the slots  64  prior to tightening the bolts  66  which secure the support arms to the support brackets  62 . Accordingly, a versatile mounting arrangement for the respective guide wheels  56  and  58  is provided as described above. 
     The construction and operation of the sheet door system  28  is believed to be within the purview of one skilled in the art based on the foregoing description. Conventional engineering materials used for flexible upward acting doors, also known as so called sheet doors, may be used to construct the door system  28 . Although a preferred embodiment has been disclosed in detail herein, those skilled in the art will also recognize that various substitutions and modifications may be made without departing from the scope and spirit of the appended claims.