Patent Publication Number: US-9410368-B2

Title: Device and method for increasing the wind load resistance and disengage-ability of overhead roll-up doors

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/270,743 entitled “Device and Method for Increasing the Wind Load Resistance and Disengage-ability of Overhead Roll-up Doors” filed Oct. 11, 2011, which claims priority to U.S. Provisional Application Ser. No. 61/466,754 entitled “Device and Method for Increasing the Wind Load Resistance and Disengage-ability of Overhead Roll-up Doors” filed Mar. 23, 2011—the contents of all of which are fully incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention is related to overhead roll-up doors, and more specifically to a device and method for increasing the wind load resistance of the door while enhancing the ability of the door and its components to disengage from a guided path if the door and/or its components are impacted by an object imparting a transverse force when the door is opening or closing. 
     BACKGROUND OF THE INVENTION 
     Overhead roll-up doors provide resistance to high winds or wind loads and/or air pressure applied to a door panel when in a partially or fully closed position. These doors are typically guided up and down in side columns or vertical guide assemblies which include a vertical path of travel for the door panel which selectively permits and prohibits access to an opening or passageway. Wind load when the door is in a substantially closed or fully closed position is particularly problematic, because as is known in the art, the wind load increases as the door panel approaches a fully closed position. As more of the door panel is exposed, a greater surface area of the door panel may become “impacted” by the wind creating the load, thereby dramatically increasing the total load on the door. 
     In addition to having to account for wind load resistance, these doors may also be installed in high-traffic areas with the potential to be impacted by objects when the door is opening or closing—a necessitating that the door panel maintain a particular level of breakaway-ability in response to such an impact. In order to avoid damage to the door (from, for example, the surrounding structure, individuals near the door, and any objects striking the door), overhead roll-up door panels are typically designed to disengage from the side columns and deviate from the path of travel when impacted by an external force to either a front or back face of the door panel. While impacts may occur at any point while the door is opening or closing, typically these impacts occur at heights greater than two to four feet as the door is opening or closing as individuals or objects attempt to sneak under a closing door or approach an opening door too quickly before it is out of the passageway. 
     In order to provide rigidity to the door panel, facilitate the proper travel of the door panel in the vertical path, and provide additional resistance to wind load (or air pressure) and other external impacts, overhead roll-up doors may include a weighted “bottom bar” attached proximate a lower or leading edge of the door panel. Such bottom bars typically extend horizontally across the bottom of the door panel a distance approximately 1″-2″ less than the distance between the side columns and a distance approximately 2″-6″ less than the width of the door panel. In an attempt to further enhance wind load resistance and guidance and engagement with the side columns, bottom bars may include an extension, like for example flexible ultra-high molecular weight (“UHMW”) plastic tabs, that extend into the vertical path of travel, engaging the side columns. These tabs are typically designed to be rigid enough to provide some resistance to air pressure, however, they must be flexible enough to allow the bottom bar to disengage from the side columns should an object impact the bottom bar or door panel. If these tabs are too flexible they may not hold up under high winds, i.e. may lead to the door becoming disengaged, even in a substantially closed position, from wind or air pressure. Conversely, if the tabs are too rigid, the bottom bar, side columns, or door panel could be damaged if the bottom bar or door panel is impacted by an object, inasmuch as the tabs may fail to release from the side columns upon impact. This inverse relationship can make door design difficult, especially in high wind or high pressure/impact areas—particularly where substantial traffic frequently passes through the opening blocked and unblocked by the door panel. 
     Regardless of whether the tabs are made to be highly flexible or extremely rigid, objects imparting a great force on the door panel or bottom bar may break the tabs completely away from bottom bar, requiring replacement of the tabs or possibly even the entire bottom bar in order to fully realize the guidance and wind load resistance capabilities of the bottom bar and door panel. In doors where engagement between the tabs and side columns is relied on to provide much of the wind load resistance, the breaking away of the tabs may lead to the door having unsatisfactory wind load resistance capabilities and creating unwanted blow out resulting from normal or even light wind loads. 
     In some door designs, in addition or instead of tabs, the bottom bar may include a structural steel angle or pivot to increase the flexibility of the bottom bar and/or further facilitate the dislodgment of the bottom bar and door panel should the bottom bar or door panel be impacted by an object. The angle may include, for example, a notch in the middle, and utilize a piece of flat bar and two sheer pins to provide rigidity and resistance to wind and maintain the shape of the bottom bar as the door panel opens and closes. If impacted, however, the sheer pins may break, allowing the bottom bar to bend at the notch and succumb to external forces, for example wind, even when in the substantially closed position. In order to prevent dislodgement of the door panel and/or bottom bar from a wind force once the sheer pins are broke, the bottom bar must be bent back into place and the sheer pins must be replaced. 
     Therefore, it would be advantageous to provide a device and method capable of providing an overhead roll-up door with satisfactory wind load resistance, particularly when the door panel is substantially or fully closed when the wind load is highest, while providing maximum breakaway-ability of the door panel if any of the door components are impacted. 
     It would be further advantageous if the device and method contained minimal parts which may otherwise need replacement or repair resulting from breakage because of impact by objects striking the door. 
     The present invention is directed to solving these and other problems. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a device and method for increasing wind load resistance of an overhead roll-up door, particularly when the door panel is in a substantially closed position, while enhancing the ability of the door and its components to disengage from the side columns and/or vertical panel guide assembly if the door or its components are impacted by a force when the door is opening or closing. 
     According to one aspect of the invention, a door assembly having a drum for winding and unwinding a flexible door panel having a width and length to permit and prohibit access through an opening is provided. The door assembly includes side columns or vertical panel guide assemblies (referred to herein as “side columns” or “vertical guides”) substantially parallel to each other, the side columns spaced apart a first distance and being disposed on opposite sides of the opening. Each of the side columns define a vertical path of travel and are configured to engage a marginal edge of the door panel as the door panel is raised and lowered. 
     According to another aspect of the invention, in order to enhance the stiffness and wind load resistance of the door panel, attached proximate a leading or bottom edge of the door panel is a bottom bar having a greater stiffness, and in some embodiments a greater thickness, than the door panel. The bottom bar may be configured to have a width extending transversally across the leading or bottom edge of the door panel a second distance less than the first distance between the side columns to prevent the engagement of the bottom bar and the side columns as the door panel opens, closes, or stops in a fully or partially closed position. 
     According to still another aspect of the invention, in order to further increase the wind load resistance of the door as the door panel approaches a substantially closed position, bottom bar guides capable of engaging and receiving at least a portion of the bottom bar may be disposed proximate a lower portion of the opening. The bottom bar guides may include a front body, a back body, and a vertical channel there between for receiving and engaging at least a portion of the bottom bar. The bottom bar guides may be made of a rigid material, which when engaging at least a portion of the bottom bar, holds the bottom bar in place and prevents it from disengaging therewith in the event the door panel experiences a high wind load or air pressure. 
     According to yet another aspect of the invention, the bottom bar guides may extend vertically from a lowermost portion of the opening a desired distance less than the vertical guides, and in preferred embodiments a distance less than or equal to 24 inches. The vertical height of 24 inches for the bottom bar guides is preferred because a distance of 24 inches between the bottom bar and lowermost portion of the opening provides enough room for the wind and air pressure to escape underneath the door panel to help insure that the bottom bar does not deviate too far from the closing path and can easily engage the bottom bar guides as the door closes. Extending the bottom bar guides a shorter vertical distance also helps prevent the locking of bottom bar to facilitate the disengagement of the door panel and bottom bar from the vertical guides if either are impacted by an object during a substantial portion of the opening and closing sequence. 
     According to another aspect of the invention, the bottom bar guides may be attached to a surface forming a lower boundary of the opening, like for example a floor, threshold, or ledge, or alternatively may be attached directly to a lower portion of the side columns themselves. 
     According to another aspect of the invention, the bottom bar guides may be attached such that the channel within the bottom bar guides substantially aligns with the vertical path of travel defined for the door panel by the vertical guides. 
     In another aspect of the invention the bottom bar guides may further include an angled face on at least a portion of the first or second bodies. The angled face(s) may be angled with respect to a plane defined by the door panel or a portion of the opening, and should be angled sufficiently to deflect any impacts to the bottom bar guides resulting from objects which may pass through the opening, like for example machines or vehicles. 
     In yet another aspect of the invention, a top portion of each of the bottom bar guides may be angled outward from the bottom bar and/or door panel. These angled top portions may form a funnel or “Y” shape in order to facilitate entry of the bottom bar into the channel formed within the bottom bar guides. The angled top portions preferably extend a distance required to “capture” and engage bottom bars which have been blown outside the ordinary path of travel due to wind or pressure as the door panel is moved to the closed position. 
     According to another aspect of the invention, the bottom bar guides may further include a connector for holding the first and second faces of the bottom bar guides together, enhancing the rigidity of the bottom bar guides, and therefore enhancing the wind load resistance of the door when the door panel is in at least a substantially closed position. The connector may be, for example, a bolt or screw, which extends through the entire bottom bar guides and prevents the bottom bar guides from deforming from pressure which is applied by the bottom bar on the bottom bar guides as a result of wind or air pressure on either side of the door panel. 
     According to another aspect of the invention, the bottom bar may include at least one end tab extending horizontally from at least one edge, and more preferably two edges, of the bottom bar. Each tab extending from an edge of the bottom bar may be the only portion of the bottom bar which engages the bottom bar guides. The total width of the bottom bar with at least one end tab extending horizontally from at least one or two edges should be less than the first distance between the side columns. 
     As should be appreciated by those having ordinary skill in the art, while narrower than the distance of the vertical guides, the width of the bottom bar with or without end tabs should remain sufficient to allow at least a portion of the bottom bar to engage the bottom bar guides when the door panel is in at least a substantially closed position. In order to accomplish this, the bottom bar guides should be disposed between the guide assemblies. Configuring the door assembly in this manner allows the bottom bar to travel between the open and closed positions, substantially free of any encumbrances, eliminating any engagement between the bottom bar and the guide assemblies, thereby minimizing any damage to the door panel, the bottom bar, and the guide assemblies resulting from an impact from an object. Since the total width of the bottom bar, including any end tabs, is less than the distance between the guide assemblies, the bottom bar and any associated end tabs may be made more rigid than standard bottom bars because the bottom bar does not have to disengage from the guide assemblies if the bottom bar or door panel is impacted. As should be appreciated, increasing the rigidity of the bottom bar increases the wind load resistance capabilities of the door when the bottom bar is engaged with the bottom bar guides when the door panel is in the substantially closed position. 
     According to another aspect of the invention, any end tabs extending horizontally from an edge of the bottom bar may be more rigid than the bottom bar itself. 
     According to another aspect of the invention, any tabs extending from an edge of the bottom bar may be thicker than the door panel while being thinner than the bottom bar. 
     According to another aspect of the invention, the door panel may be constructed from rubber or other stiffer materials in order establish enough wind resistance during the opening and closing sequence when the bottom bar is not engaged with the bottom bar guides. However, as should be appreciated by those having ordinary skill in the art, the door panel may be constructed of any material, so long as the material, either through its compositional properties or thickness, provides sufficient resistance to the wind load imposed on the door panel during the opening and closing sequence when the bottom bar is not engaged with the bottom bar guides. 
     Other aspects and features of the invention will become apparent to those having ordinarily skill in the art upon review of the following Description, Claims, and associated Drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front view of a door assembly as contemplated by the invention with a door panel in a substantially open position. 
         FIG. 2  is a front view of a door assembly as contemplated by the invention with a door panel in a partially opened position. 
         FIG. 3  is a cross-sectional view taken along the line C-C in  FIG. 2 . 
         FIG. 4  is a cross-sectional view taken along the line B-B in  FIG. 2 . 
         FIG. 5  is a cross-sectional view taken along the line A-A in  FIG. 2 . 
         FIG. 6  is a front view of a door assembly as contemplated by the invention with a door panel in a substantially closed position. 
         FIG. 7  is a cross-sectional view taken along the line C-C in  FIG. 6 . 
         FIG. 8  is a cross-sectional view taken along the line B-B in  FIG. 6 . 
         FIG. 9  is a cross-sectional view taken along the line A-A in  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE PRESENT INVENTION 
     While the present invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail, preferred embodiments of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to the embodiments illustrated. 
       FIGS. 1, 2, and 6  show a door assembly  10  in a substantially open position, partially closed position, and substantially closed position, respectively. Door assembly  10  includes side columns  12 ,  14 , flexible door panel  16 , drum  18  for winding and unwinding flexible door panel  16  to permit and prohibit access to opening  20 , bottom bar  22  attached proximate leading or bottom edge  24  of door panel  16 , and bottom bar guides  26 ,  28  disposed proximate a lower portion of opening  20 . 
     It is contemplated by the invention that bottom bar  22  may be any bottom bar structure known in the art and may incorporate any desirable features known to be used with bottom bar structures in overhead roll-up doors. For example, bottom bar  22  may include a safety edge or other structure capable of deforming if bottom bar  22  is lowered on an object as a result of door panel  16  closing. Alternatively, bottom bar  22  may include a sensor or sensors capable of detecting an impact on the bottom bar and providing a signal to a motor or control circuitry for the overhead door to immediately open door panel  16  in response to the impact. Sensors which are known in the art include, but are not limited to sensors capable of detecting objects impacting a front or back face of the bottom bar, or capable of detecting objects which have been struck by a lower edge of the bottom bar that the door panel has closed on top of. As a further alternative, the lower edge of bottom bar  22  may include a motion detection sensor or the like capable of detecting motion underneath the door panel as it closes, the sensor capable of providing a signal to a motor or control circuitry for the door to prevent the door panel from closing further until no motion is detected. 
     Side columns  12 ,  14  are disposed on opposite sides of opening  20  and extend parallel to each other a vertical distance along substantially the entire height of opening  20 . As seen in  FIGS. 3 and 7 , which are cross-sections along lines C-C in  FIGS. 2 and 6 , respectively, side column  12  contains path  30  which allows side column  12  to engage door panel  16 , and defines a vertical path of travel for marginal edge  32  of flexible door panel  16  when door panel  16  is either opening, closing, or in a substantially closed position. Though only shown in a single position in  FIG. 3 , it should be appreciated by those having ordinary skill in the art that the relationship between side column  12 , path  30 , and marginal edge  32  of door panel  16  remains constant throughout the entire opening and closing sequence. Though not shown, the relationship shown in  FIG. 3  for side column  12  is substantially a mirror image of the relationship of side column  14 , door panel  16 , and a corresponding path and marginal edge contained therein on the opposite side of opening  20 . 
     As seen in  FIG. 7 , in alternative embodiments of the invention, thickened edge  34  may be attached proximate marginal edge  32  of door panel  16 . Thickened edge  34  may interact with side columns  12 ,  14  to enhance the wind load resistance of door assembly  10  while door panel  16  is opening or closing. As should be appreciated by those having ordinary skill in the art, thickened edge  34  may be attached to marginal edge  32  as either a continuous body, or more preferably, as a segmented body leaving gaps, i.e. exposed portions of marginal edge  32 , between thickened edges  34 . Segmenting thickened edges  34  provide a substantially increased wind load resistance for door assembly  10  while door panel  16  is opening or closing, while providing less resistance for door panel  16  to disengage from side columns  12 ,  14  should door panel  16  or bottom bar  22  be impacted by an external force while door panel  16  is opening or closing. 
     In some alternative embodiments, a continuous thickened edge wind lock may be used wherein the edge contains at least two portions having different durometers and/or at least a portion of the face of the thickened edge contains at least two ribs and one groove or channel located there between. Utilizing different durometers and/or rib structures on a face of the thickened edge will help to facilitate the wind load resistance of the door panel while also providing the door panel the ability to disengage from the side columns should it be impacted by an object. 
     As is seen in  FIGS. 2 and 6 , bottom bar guides  26 ,  28  are configured to be capable of engaging bottom bar  22  when door panel  16  is in at least a substantially closed position. Though bottom bar guides  26 ,  28  are shown in  FIGS. 1, 2, and 6  as being disposed on opposite sides of opening  20 , bottom bar guides  26 ,  28  may be disposed at any point along opening  20  wherein they will engage bottom bar  22  when door panel  16  is in a substantially closed position. In the preferred embodiment, however, bottom bar guides  26 ,  28  extend vertically on opposite sides of the opening, just inside, and parallel to side columns  12 ,  14 . As should be appreciated by those having ordinary skill in the art, the closer to the outside of opening  20  bottom bar guides  26 ,  28  are located, the larger the pathway for passing through opening  20  is when door panel  16  is in a partially or substantially open position. 
     Regardless of whether bottom bar guides  26 ,  28  are attached proximate opposing sides of opening  20 , they may be attached to any structure which will allow them to engage bottom bar  22  when door panel  16  is in a substantially closed position. For example, bottom bar guides may be attached to a surface forming a lower boundary of the opening, like for example a floor, threshold, or ledge, or alternatively may be attached directly to side columns  12 ,  14 . 
     While bottom bar guides  26 ,  28  may be any height which allows them to fully engage bottom bar  22  when door panel  16  is in at least a substantially closed position, as shown in  FIGS. 1, 2, and 6 , it is preferable that bottom bar guides  26 ,  28  extend vertically a distance less than side columns  12 ,  14 , and more preferably a distance equal to or less than 24 inches. The height of bottom bar guides  26 ,  28  may be set at any desired level to allow bottom bar  22  to travel free and loose after a desired height, thereby minimizing any damage incurred should an object impact the door panel  16  and/or bottom bar  22 . 
     As should be appreciated by those having ordinary skill in the art, the height of bottom bar guides  26 ,  28  may be adjusted to meet the requirements of the door installation. However, it should be appreciated that the vertical height of bottom bar guides  26 ,  28  directly affects the increase in wind load resistance of the door and the disengage-ability of the door in an inverse ratio. As the vertical height of bottom bar guides  26 ,  28  increase, the wind load resistance of door assembly  10  may substantially increase along a greater portion of the path of travel of door panel  16 , e.g. two feet of increased wind load resistance from bottom bar  22  and bottom bar guides  26 ,  28  engaging versus four feet of increased wind load resistance, and better insures the capture of bottom bar  22  by bottom bar guides  26 ,  28  because the bottom bar will be captured at an earlier point in the closing sequence before wind, for example, blows the bottom bar out of alignment with the bottom bar guides and path  30  contained therein. However, increasing the height of the bottom bar guides inhibits the disengage-ability of door panel  16  and bottom bar  22  if impacted substantially along a portion of the path of travel the bottom bar guides are extended along. Conversely, as the vertical distance of the bottom bar guides decrease, the wind load resistance of the door panel substantially decreases along a greater portion of the path of travel of the door panel while the disengage-ability of the door and its components if impacted along a greater portion of the path of travel increases. 
     In order to combat this inverse relationship and combat the loss of disengage-ability in the face of increased wind load resistance, it is contemplated by the invention that bottom bar guides  26 ,  28  may be made of a flexible or a combination of a flexible and rigid material. For example, if bottom bar guides  26 ,  28  extend vertically a distance of 24 inches from the lower boundary of the opening, it is contemplated that the first 18 inches of the bottom bar guides engaged by bottom bar  22  may be made of a semi-flexible material, while the last 6 inches of bottom bar guides  26 ,  28  engaged by bottom bar  22  may be made of a rigid material. Utilizing flexible and rigid materials allows for the benefits of aligning the bottom bar in the bottom bar guides and preventing blowout as the wind load on door panel  16  is increased as it approaches the closed position while still maintaining the disengage-ability of door panel  16  and bottom bar  22  if impacted by an object when the bottom bar is engaged by the flexible portion of the bottom bar guides. 
     As should be appreciated by those having ordinary skill in the art, utilizing bottom bar guides having different flexibilities or rigidities is particularly advantageous where wind load resistance is of the utmost importance in high traffic areas. By utilizing differing flexibilities or rigidities, bottom bar guides  26 ,  28  may be a greater vertical height, like for example four, six, eight or ten feet rather than two feet, so a portion of bottom bar  22  may engage bottom bar guides  26 ,  28  to insure alignment of bottom bar  22  with guides  26 ,  28  and to prevent door panel  16  from blowing out of side columns  12 ,  14  or bottom bar  22  out of alignment with guides  26 ,  28 —because the more flexible bottom bar guide portions may flex and allow bottom bar  22  to escape if an object impacts door panel  16  or bottom bar  22 . 
     In order to achieve the differing flexibilities in portions of bottom bar guides  26 ,  28 , it is contemplated by the invention that different materials may be used to form bottom bar guides  26 ,  28 , like for example a flexible plastic and a rigid metal. Alternatively, the same material may used but treated or given different qualities to insure that one portion of the bottom bar guides  26 ,  28  are more flexible than another. For example, bottom bar guides  26 ,  28  may be made entirely of metal, however a portion may be treated with a chemical or impregnated with an additive which increases the flexibility of the metal, while another portion may be treated with a chemical or impregnated with an additive which increases the rigidity of the metal. As yet a further alternative, bottom bar guides  26 ,  28  may be made of differing or increasing thicknesses from the vertical high point on bottom bar guides  26 ,  28  to a point proximate the lower most portion of the guides. As yet a further alternative, a lower portion of bottom bar guides  26 ,  28  may include an additional or separate structure as part of the guide or attached thereto to increase the rigidity. It is also contemplated that the same or different types of metals be used with varying flexibility characteristics. Indeed, any means of altering the flexibility and/or rigidity of bottom bar guides  26 ,  28  may be used in order to created a guide which is flexible in at least one portion while being less flexible (more rigid) in at least one portion. 
     In order to enhance the rigidity of bottom bar guides  26 ,  28 , and therefore enhance the wind load resistance of door assembly  10 , bottom bar guides  26 ,  28  may further include a connector  36  to hold a front portion or body of the guide together with a back portion or body of the guide. As seen in  FIGS. 4 and 8 , which are cross-sections along lines B-B in  FIGS. 2 and 6 , for example, connector  36  may cross a channel  38  located on the interior of bottom bar guides  26 ,  28 . Since channel  38  receives and guides bottom bar  22  when door panel  16  is in a substantially closed position, and depending on the height of the bottom bar guides  26 ,  28  the channel may also receive a portion of door panel  16  above bottom bar  22 , as seen in  FIG. 5 , (which is a cross-section along line C-C in  FIG. 2 ), it is preferable to place connector  36  at as low a point vertically as possible while still recognizing the effects of connector  36 . Alternatively or additionally, it may be advantageous to place connector  36  on an interior portion of bottom bar guides  26 ,  28  proximate side columns  12 ,  14  where bottom bar  22  does not extend. For example, if bottom bar  22  is two inches shorter than distance Y between side columns  12 ,  14 , and bottom bar guides  26 ,  28  are located adjacent side columns  12 ,  14 , connector  36  may be placed in the one inch area in each bottom bar guide  26 ,  28  that bottom bar  22  does not penetrate and engage. Connector  36  may be a bolt, a screw or any other element known in the art which is capable of connecting two elements together for the purpose of forming a stronger connection. 
     As seen in at least  FIGS. 1, 2, and 6 , bottom bar  22  has a width W less than distance Y between side columns  12 ,  14 , and more preferably between 1 inch and 6 inches less than distance Y. While less than distance Y, it should be appreciated by those having ordinary skill in the art, that width W of bottom bar  22  should be sufficient to engage bottom bar guides  26 ,  28 , i.e. greater than distance X between the bottom bar guides  26 ,  28 , in order to achieve the requisite wind load resistance when door panel  16  is in at least the substantially closed position. 
     In order to engage bottom bar  22  with bottom bar guides  26 ,  28 , and since width W of bottom bar  22  is less than distance Y between side columns  12 ,  14 , in the preferred embodiment bottom bar guides  26 ,  28  should be disposed between side columns  12 ,  14 . Disposing bottom bar guides  26 ,  28  between side columns  12 ,  14  does, however, expose bottom bar guides  26 ,  28  to impacts from objects, vehicles, machines, or the like that pass through opening  20 . In order to prevent damage to bottom bar guides  26 ,  28  from such impacts, at least one face  36 , and more preferably at least two faces  36 ,  38 , of bottom bar guides  26 ,  28  may be angled with respect to a plane defined by door panel  16  or an edge of opening  20  in order to deflect any impacts in order to protect bottom bar guides  26 ,  28 . Examples of angled faces  40 ,  42  which may be utilized can be found in  FIGS. 3, 4, 7, and 8 . While angled faces  40 ,  42  are described as being angled with respect to door panel  16 , it should be appreciated by those having ordinary skill in the art that the purpose of “angling” the faces is to provide a surface which may deflect objects that may impact bottom bar guides  26 ,  28  which are passing through the opening in either direction. 
     It is contemplated by the invention that in addition to or in the alternative to being angled, faces  40 ,  42  may be made of a resilient pliable material capable of deforming and giving upon impact to protect the impacting object and bottom bar guides  26 ,  28 . While any material may be used, examples include a foam or plastic face attached to or formed as part of bottom bar guides  26 ,  28  so as to allow for a rigid, unyielding interior, while providing an angled or unangled pliable face or portion which can receive an impact and reform while protecting the interior of bottom bar guides  26 ,  28 . 
     In order to facilitate engagement with bottom bar  22 , a top portion  44  of each of bottom bar guides  26 ,  28  may be angled outward from door panel  16  and bottom bar  22 , as seen in  FIGS. 5 and 9  which are cross-sections along line A-A in  FIGS. 2 and 6 , respectively. Angling top portion  44  of bottom bar guides  26 ,  28  outward from door panel  16  and bottom bar  22  creates a greater area for “capturing” or “engaging” bottom bar  22  as door panel  16  is closing, thereby insuring bottom bar guides  26 ,  28  engage and guide bottom bar  22  in channel  38 . 
     While bottom bar  22  may directly engage bottom bar guides  26 ,  28  when door panel  16  is in at least a substantially closed position, in order to further facilitate engagement of bottom bar  22  and bottom bar guides  26 ,  28 , bottom bar  22  may include at least one end tab  46  or  48  extending horizontally from at least one edge  50  or  52  for engaging bottom bar guides  26 ,  28 . As seen, for example, in  FIGS. 1 and 2 , at least one end tab  46 ,  48  may extend horizontally from at least two edges  50 ,  52 . End tabs  46 ,  48  should be of sufficient stiffness to withstand external forces, such as high gusts of wind, and therefore may preferably be made of a stiff material, such as rigid steel or hard plastic, however it should be appreciated by those having ordinary skill in the art that tabs  46 ,  48  may be made of flexible materials. Making tabs  46 ,  48  from a flexible material may increase the disengage-ability of the bottom bar and tabs from the bottom bar guide stops should the bottom bar or door panel be impacted. It is also contemplated that tabs stiffer than the bottom bar may be utilized to facilitate the strongest possible wind lock. 
     In embodiments where bottom bar  22  includes end tabs  46 ,  48 , it is advantageous to limit engagement between bottom bar  22  and bottom bar guides  26 ,  28  to only end tabs  46 ,  48 . In a preferred embodiment, the thickness of end tabs  46 ,  48  may be substantially similar to the thickness of door panel  16 . Limiting engagement in such embodiments to only end tabs  46 ,  48  may allow for channel  38  which receives bottom bar  22 , and therefore bottom bar guides  26 ,  28 , to be smaller with respect to opening  20 —allowing channel  38  to be substantially identical in width to path  30 . Limiting engagement to only end tabs  46 ,  48  also insures a tight seal between bottom bar  22  and bottom bar guides  26 ,  28  inasmuch as it eliminates the possibility that a variation in thickness between the core  54  of bottom bar  22  and end tabs  46 ,  48  affect the wind load resistance of door assembly  10  when door panel  16  is in a substantially closed position. 
     It is further contemplated by the invention that the end tabs may be made of a thickness greater than door panel  16  but less than bottom bar  22 . Utilizing end tabs of such a thickness insures that the end tabs do not engage side columns  12 ,  14  during, for example, the opening or closing or any re-alignment sequences, as the tabs may be sized so as not to fit within any opening accepting door panel  16 . Sizing any end tabs to have a thickness smaller than bottom bar  22  and adjusting bottom bar guides  26 ,  28  and path  30  insures that bottom bar  22  does not engage bottom bars  26 ,  28 , insuring a proper wind lock when door panel  16  is in a substantially closed position. 
     As described above, width W of bottom bar  22  and end tabs  46 ,  48  should be less than distance Y between side columns  12 ,  14 , and preferably about 1 inch less with core  54  of bottom bar  22  being about 6 inches less. Since the combined width W of bottom bar  22  and end tabs  46 ,  48  is less than distance Y between side columns  12 ,  14 , and as should be appreciated by those having ordinary skill in the art, end tabs  46 ,  48  may be made more rigid than known end tabs of known end tabs bottom bars, thereby substantially increasing the wind load resistance of door assembly  10  when end tabs  46 ,  48  are engaged with bottom bar guides  26 ,  28 . 
     The alignment and engagement of bottom bar  22  having end tabs  46 ,  48  with bottom bar guides  26 ,  28  can be seen in  FIGS. 4 and 8 . As seen in  FIG. 4 , as bottom bar  22  approaches bottom bar guide  26 , end tab  46  substantially aligns with channel  38  (as discussed above, in order to accommodate for variation in the location of end tab  46 , the top portion  44  may be angled outward from bottom bar  22  to facilitate alignment). As door panel  16  is lowered to at least a substantially closed position, as seen in  FIG. 8 , end tab  46  engages bottom bar guide  26 , being guided and locked within channel  38 , forming a substantially stronger wind lock for door assembly  10 . 
     In order to further facilitate alignment, in a preferred embodiment, the weight of bottom bar  22  should be centered in an area substantially co-planer with door panel  16 . Centering the weight of bottom bar  22  in an area of the bottom bar that is substantially co-planar with door panel  16  helps bottom bar  22 , and if included end tabs  46 ,  48 , maintain a substantially vertical alignment, enhancing the engagement between bottom bar  22  and bottom bar guides  26 ,  28 . While top portions  44  of each of the bottom bar guides  26 ,  28  will still capture bottom bar  22  and/or end tabs  46 ,  48  if the weight distribution of bottom bar  22  is such that it reaches bottom bar guides  26 ,  28  at an angle, centering the weight of bottom bar  22  under door panel  16  insures that bottom bar  22  and/or end tabs  46 ,  48  will engage bottom bar guides  26 ,  28 . 
     The above-described embodiments of the present invention are intended to be examples only. Alterations, modifications and variations may be effected to the particular embodiments by those of ordinary skill in the art without departing from the scope of the invention, which is defined by the claims appended hereto.