Description of Related Art A roll-up door typically includes a pliable roll-up panel or curtain that is wound about an overhead roller. Some door curtains are made of flexible fabric reinforced with several vertically spaced horizontal stays or wind bars that are relatively rigid to help prevent the curtain from billowing when subject to air pressure differentials across opposite faces of the curtain. Other curtains comprise a series of narrow, relatively rigid metal bars or segments that each extend horizontally across the doorway. The segments are pivotally interconnected along their horizontal edges, so that the curtain can wrap around the overhead roller. Regardless of the type of curtain, the operation of a roll-up door is generally the same.

To close the door, the roller pays out the curtain as two vertical tracks disposed along either side edge of the doorway guide the side edges of the curtain generally along a vertical plane across the doorway. The rotation of the roller is reversed to open the door. Roll-up doors are typically either powered open and closed, or are powered open and allowed to fall closed by gravity.

Sometimes, the curtain is accidentally forced out from within its vertical guides due to any one of a variety of causes, such as a vehicle striking the curtain or the curtain closing on an obstruction in the doorway. For continued operation, the curtain needs to be returned to its normal position within the tracks. This can be done manually.

Alternatively, the door may be capable of automatic reinsertion following breakaway.

Toward that end, the door will typically include refeed guides or brackets that are mounted just above the vertical tracks and serve as lead-ins that guide the curtain back into the tracks as the dislodged curtain is being pulled past the guides and rolled onto the roll tube. The roller then lowers the curtain back down, and the refeed guides further guide the lower edge of the curtain back into its proper position within the tracks.

In many industrial settings, such as in factories and warehouses, roll-up doors are opened as rapidly as possible to help avoid collisions between a vehicle and a partially opened door. However, if the curtain's take-up roller turns too fast, centrifugal force acting on the curtain as the curtain starts wrapping (or unwrapping) around the roller can throw the curtain outward, away from the roller. This can occur in either direction, i. e., the door can be opening or closing.

Often, a loud banging noise is created if the frame or other structure of the door is struck by a curtain constructed of rigid metal segments or struck by a fabric curtain's wind bars. If some of the wind bars are bent, the problem can get worse.

Summary of the Invention For a roll-up door having a curtain that wraps around a roller, in order to minimize the noise or damage caused by the curtain or portions of the curtain striking other portions of the door, in one embodiment a polymeric shroud is disposed around the door's roller, such that the curtain travels between the shroud and the roller.

In some embodiments the shroud is a continuous strap curved in a generally omega-shape.

In some embodiments, the shroud includes a tapered lead-in that guides the curtain as the roller draws in the curtain to open the door.

In some embodiments, the shroud includes a tapered lead-in that guides the lower edge of the curtain back into vertical guide tracks after the curtain has been dislodged out from within the tracks.

In some embodiments, the shroud is used with a fabric door curtain that is reinforced with metal wind bars.

In some embodiments, the shroud is used with a door curtain made of a series of horizontally elongated bars that are pivotally interconnected along their horizontal edges. Brief Description of the Drawings Figure 1 is a partial cutaway front view of a partially opened roll-up door with an

upper portion of the door's curtain wrapped around an overhead roller, wherein a shroud is disposed around the roller.

Figure 2 is a cross-section end view taken along line 2-2 of Figure 1.

Figure 3 is an end view of one embodiment of a door curtain.

Figure 4 is a perspective view of the door of Figure 1, but with the curtain removed and top and front header panels removed to more clearly show the shroud and its relationship to the door's roller.

Figure 5 is similar to Figure 2, but showing the curtain dislodged out from within its vertical guide tracks and showing a refeed feature of the shroud guiding a previously dislodged curtain back into the door's vertical guide tracks.

Figure 6 is similar to Figure 2, but showing a re-fed curtain as it re-enters the vertical guide tracks.

Description of the Preferred Embodiment A partially opened roll-up door 10, shown in Figures 1 and 2, includes a flexible door panel or curtain 12 that is wound about an overhead roller 14. To open or close door 10 relative to a doorway 16, roller 14 can be manually rotated or powered by a conventional drive 18 to draw in or pay out curtain 12. As curtain 12 moves between its open and closed positions, vertically elongated guides 20 disposed along either side edge of doorway 16 guide two side edges 22 and 24 of curtain 12 generally along a vertical

plane across doorway 16.

The actual structure of guides 20 can be of a wide variety of designs that are well known to those of skill in the art. Perhaps the simplest structure would be a rigid channel having two flanges between which curtain 12 travels. In other embodiments; however, guide 20 includes two fabric straps 26 that are each held preferably taut between a lower anchor 28 and an upper anchor 29. A gap 30 running vertically between two generally parallel straps 26 provides a path along which edges 22 or 24 of curtain 12 may travel.

Further details of such a guide can be found in published PCT application W098/48139 (October 29,1998), which is specifically incorporated by reference herein.

As with guides 20, curtain 12 may also assume a variety of structures well known to those skilled in the art. For example, curtain 12 can be made of fabric (i. e., any flexible sheet of material), as shown in Figures 1 and 2, or made of a series of horizontally elongated metal panels 32 that are pivotally interconnected along their horizontal joints 34, as schematically illustrated in Figure 3. When made of fabric, curtain 12 may or may not include horizontal wind bars 36. Wind bars 36 can be made of relatively rigid metal, which can help prevent curtain 12 from billowing when subject to air pressure differentials across opposite faces of the curtain. If used, wind bars 36 can be held in place by integral pockets 38 that are sewn or heat welded to the fabric of curtain 12.

To limit the radial separation of curtain 12 from roller 14, a shroud 40 is disposed at least partially around roller 14, as shown in Figures 1,2 and 4. This helps prevent curtain 12 and/or wind bars 36 from striking certain portions of door 10 as door 10 opens

and closes. Without shroud 40, roller 14 centrifugally throwing curtain 12 outward can cause curtain 12 to strike or rub against a metal header panel, such as a face panel 46 lying along a generally vertical plane or a top panel 48 lying along a generally horizontal plane above roller 14. Besides header panels, shroud 40 can also help prevent curtain 12 from striking other portions of a door. Shroud 40 can be generally circular or be of another shape and preferably extends most of the way around roller 14, i. e. shroud 40 extends at least 180-degrees around roller 14. However, shroud 40 could also extend just 90-degrees around (or even less) to help shield just one of the header panels 46 or 48.

Conventional brackets 42 can be used to attach shroud 40 to a side frame member 44 of door 10. An additional left-hand shroud 40', identical or similar to shroud 40, can be installed on the left side of doorway 16. A single shroud extending the full width of curtain 12, or a single narrower shroud situated anywhere between edges 22 and 24 of curtain 12 are also well within the scope of the invention.

To minimize wear on curtain 12 and to minimize noise created by curtain 12 striking or rubbing against shroud 40, shroud 40 is preferably made of a polymer. For example, UHMW (ultrahigh molecular weight polyethylene) provides some vibration absorption and has a desirably low coefficient of friction with many door curtain materials. However, shroud 40 can also be made of materials other than plastic. For example, even when made of metal, shroud 40 may still reduce noise, as the relatively small shroud 40 may reverberate less than a much larger header panel.

In some embodiments, shroud 40 cannot only provide a curtain containment function, but can also provide a curtain-refeed function to restore a dislodged curtain to

its normal operating position within vertical guides 20. The two functional features can be integrated into a single, unitary shroud. For example, in some embodiments, shroud 40 comprises a sheet, strap or bar curved in a generally omega-shape, with a lower portion 52 of the omega shape providing the refeed function. Portion 52 of the omega- shape includes a lower lead-in 54, an upper lead-in 56, and a throat 58 interposed between the two. An upper portion 60 of the omega-shape defines a main opening 62 through which roller 14 extends. Thus, the omega-shape creates a generally smooth, continuous path 64 along which curtain 12 can travel up and down in series through main opening 62, upper lead-in 56, throat 58, and lower lead-in 54. When curtain 20 becomes dislodged out from within gap 30'.. as shown in Figure 5, portion 52 of shroud 40 can refeed curtain 20 back into gap 30 upon roller 14 being rotated to roll the curtain 12 onto the roller 14. The lower lead-in 54 illustratively guides curtain 12 back into the throat region 58 so that it can be smoothly wound onto the roller 14. Roller 4 can subsequently lower edge 66 back into gap 30, as shown in Figure 6. As door 10 closes, upper lead-in 56 guides curtain 12 as curtain 12 travels downward from roller 14 towards the upper portion 50 of guide 20. To help ensure that leading edge 66 of curtain 12 enters gap Sn between the upper ends 50 of straps 26, in some embodiments, a width 68 of throat 58 is less than a width 70 of gap 30. However, in other embodiments, throat width 68 is equal to or greater than gap width 70.

Although the invention is described with reference to a preferred embodiment, it should be appreciated by those skilled in the art that various modifications are well within the scope of the invention. For example, although shroud 40 is preferably formed of one

continuous polymeric strap that creates the entire omega-shape, shroud 40 could also be comprised of separate segments. Some segments of the shroud could shield certain portions of the door from being struck by curtain 12, other segments could serve as the upper lead-in, and still other segments could serve as the lower lead-in. Moreover, shroud 40 does not necessarily have to be made of plastic, but can be made of metal and other materials, as well. Therefore, the scope of the invention is to be determined by reference to the claims that follow.

I claim: