Abstract:
A dual curtain closure system for reversibly covering a portal opening, wherein the upper end of each curtain is attached across an upper margin of the opening and the lower end of each curtain is folded back on itself to form an upwardly opening pocket. Each pocket supports an elongated rod, the ends of which are engaged by opposing channel members defining the lateral margins of the portal opening. The sides of each curtain comprise loop fastening material and the channel members comprise hook fastening material such that the curtains are sealed to the channel members when activated to cover the opening. The hook fastening material has only downwardly facing hooks to prevent curtain hang up and promote proper operation of the closure system.

Description:
FIELD OF THE INVENTION 
     The present invention relates to closures for windows, doors, or other portals. More particularly, the present invention relates to a dual curtain closure system utilizing hook and loop fastening material to attach roll-up curtains to the lateral margins of a portal. 
     BACKGROUND OF THE INVENTION 
     Sealable curtain systems are known in the prior art. One such sealable curtain taught in U.S. Pat. No. 5,566,736 to Crider et al., incorporated herein by reference, and specifically shown in FIG. 5 of the &#39;736 patent, has two curtains, two channel members, and two elongated rods. The channel members are C-shaped and the lateral ends of each elongated rod are slidably secured therein. Each rod is supported by a single curtain and each curtain is designed to form a seal with only the adjacent lateral side of each channel member. Affixed to the longitudinal sides of each curtain and the lateral sides of the channel members are complementary closure members, such as hook and loop fastening material. 
     Due to the structure of the &#39;736 patent system, when the curtains are not at their bottommost positions, the portion of each longitudinal side of the first curtain having loop fastening material affixed directly thereto abuts almost the entire circumference of the rod captured within the pocket of the first curtain. If an exterior force is applied to the first curtain, the first curtain rod is urged in the same direction. If the exterior force is adequate and in the general direction towards the lateral sides of the channel members not adjacent to the first curtain, the first curtain may detach from the adjacent lateral side of the channel member and attach to the nonadjacent lateral side of the channel member due to the engagement of the loop fastening material affixed to the longitudinal side of the first curtain with the hook fastening material affixed to the nonadjacent lateral side of the channel member. Following such an event, the first curtain must be detached from the nonadjacent lateral side of the channel member and raised above the point at which the initial detachment occurred so that the curtains may be lowered along their intended paths. 
     In an attempt to overcome the foregoing problem, the mating hook and loop fasteners on each curtain and corresponding lateral side of each channel member were (1) reduced in width and (2) the mating hook and loop fasteners on one lateral side of a channel member were offset from the mating hook and loop fasteners on the opposite lateral side of the channel member. Thus, if the first curtain was detached from its adjacent lateral side of a channel member, it was prevented from attaching to the nonadjacent lateral side of the channel member because the loop fastener on the first curtain did not align with the hook fastener on the nonadjacent lateral side of the channel member. Although these modifications greatly reduced curtain hang up, other problems arose. Specifically, the reduced width of the mating hook and loop fasteners led to a less secure seal. Also, if a curtain was slightly misaligned with the lateral side of a channel member, the reduced width of the mating hook and loop fasteners sometimes led to inadequate overlap and, consequently, insufficient sealing between the mating hook and loop fasteners. This sometimes also resulted in creases forming in the curtains, which if recurrent, reduced the life of the curtains. 
     Accordingly, what is needed is an apparatus that overcomes the foregoing problems and allows each longitudinal side of each curtain to become sealably attached to only the adjacent lateral side of each channel member. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing disadvantage inherent in sealable curtain systems utilizing hook and loop fastening material, the present invention provides an improved dual curtain closure system wherein the same is able to form a sealing engagement between each longitudinal side of a sealable curtain and the adjacent lateral side of each channel member, while resisting forming a sealing engagement between the longitudinal side of the curtain and the nonadjacent lateral side of each channel member. To attain this, the preferred embodiment of the present invention is a sealable curtain system having two flexible covers or curtains selected from a material suitable to affect the type of closure sought. For example, if the closure is to allow ventilation but obstruct light, the material of the curtain would be of a weave that would be permeable to air but block a certain amount of light. Similarly, the closure could be impervious to moisture yet permeable to air, or vapor proof yet transparent, or opaque and vapor proof as the needs of the building on which the closure is used require. 
     The curtains are at least as wide as the portal opening to be covered and are longer than the height of the opening. The curtains are sealed by means of hook and loop fastening material, such that each lateral margin of each curtain has a strip of loop fastening material affixed thereto, and a complementary strip of hook fastening material is affixed to the inside of the adjacent lateral side of the adjacent channel member. The hook fastening material has only downwardly facing hooks. The top end of each curtain is rigidly affixed across the top of the portal opening. The opposite ends of the curtains are upturned and connected to a driven take-up roller mounted above the portal opening, thus forming a pocket in each curtain. Two elongated rods extend lengthwise through the pockets and across the portal opening, thus each elongated rod is supported within a pocket of one curtain with the ends of the elongated rod captured within the channel members. The rods are maintained at different heights relative to each other. Activation of the driven take-up roller lengthens or shortens the effective length of the curtains and moves the rods upwardly or downwardly within the channels such that the mating hook and loop fasteners are positioned to seal and unseal the curtains to the channel members. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front perspective view of the present invention shown partially in section. 
         FIG. 2  is a side sectional view of the invention taken along line  2 - 2  of  FIG. 1  with the curtains shown in a lowered position. 
         FIG. 3  is a side sectional view of the invention of  FIG. 2  with the curtains shown in a partially raised position. 
         FIG. 4  is a top sectional view of the invention taken along line  4 - 4  of  FIG. 1 . 
         FIG. 5  is an enlarged side sectional view of the invention showing the curtains being lowered. 
         FIG. 6  is an enlarged side sectional view of the invention showing the curtains being raised. 
         FIG. 7  is an enlarged side sectional view of the invention showing the lower curtain partially detached from its adjacent lateral side of the channel member and contacting the nonadjacent lateral side of the channel member. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The preferred apparatus of the dual curtain closure system is indicated generally by the numeral  10 . As best shown in  FIG. 1 , the apparatus  10  has first  12   a , second  12   c , third  13   a , and fourth  13   c  attachment members. The attachment members  12   a ,  12   c ,  13   a ,  13   c  each extend the full vertical length of the portal opening  11  to be covered and each terminate at a lower end  14 , which may be, for example, a floor or an upwardly opening channel member which extends across the width of the opening  11 . The attachment members  12   a ,  12   c ,  13   a ,  13   c  are positioned in pairs such that the first  12   a  and second  12   c  attachment members define one lateral margin of the opening  11  and the third  13   a  and fourth  13   c  attachment members define the opposing lateral margin of the opening  11 . The distance between the first  12   a  and second  12   c  attachment members is preferably equal to the distance between the third  13   a  and fourth  13   c  attachment members. As best shown in  FIG. 4 , each attachment member  12   a ,  12   c ,  13   a ,  13   c  has an inner surface  120   a ,  120   c ,  130   a ,  130   c  and the inner surfaces of each pair of attachment members preferably face one another. Preferably, each pair of attachment members is part of a channel member, such that the apparatus  10  has first  12  and second  13  channel members. The first channel member  12  preferably has first  12   a  and second  12   c  attachment members as well as a perpendicular member  12   b  attached therebetween and the second channel member  13  likewise preferably has third  13   a  and fourth  13   c  attachment members as well as a perpendicular member  13   b  attached therebetween. Each perpendicular member  12   b ,  13   b  is preferably substantially orthogonal to both attachment members attached thereto such that each channel member  12 ,  13  is cross-sectionally substantially C-shaped. Each channel member  12 ,  13  is preferably directed inwardly such that the channels formed by the C-shaped channel members  12 ,  13  face one another. The channel members  12 ,  13  and lower end  14  are preferably made of a durable material capable of resisting wear, such as metal. 
     The apparatus  10  has a first brace or bar  17  and second brace or plate  37 . Each brace  17 ,  37  preferably extends across the width of the opening  11  and is mounted superjacent the opening  11 . Each brace  17 ,  37  has opposing ends, each of which is preferably attached to a channel member  12 ,  13 . The braces  17 ,  37  are preferably made of metal for increased durability. Attached to the first brace  17  is a first end  19  of a first curtain  18  and attached to the second brace  37  is a first end  39  of a second curtain  38 . Each curtain  18 ,  38  is preferably a flexible material selected in accordance with the purposes of the present invention for the ability of the curtain  18 ,  38  to block or transmit light, air, or moisture from one side of the curtain  18 ,  38  to the other. The length of each curtain  18 ,  38  is preferably greater than the length of the lateral margins of the opening  11  such that each curtain  18 ,  38  is capable of covering the entire opening  11 . The first curtain  18  has first  21  and second  22  longitudinal sides and the second curtain  38  has first  41  and second  42  longitudinal sides with the first longitudinal side  21 ,  41  of each curtain  18 ,  38  positioned along the same lateral margin as the first channel member  12  and with the second longitudinal side  22 ,  42  of each curtain  18 ,  38  positioned along the same lateral margin as the second channel member  13 . Each curtain  18 ,  38  has an interior surface  18   a ,  38   a  and an exterior surface  18   b ,  38   b . When the curtains  18 ,  38  are in a lowered position, the interior surfaces  18   a ,  38   a  preferably face one another and the exterior surfaces  18   b ,  38   b  preferably face away from the opening  11 . 
     Each longitudinal side  21 ,  22 ,  41 ,  42  of each exterior surface  18   b ,  38   b  of each curtain  18 ,  38  is releasably attachable to one attachment member  12   a ,  12   c ,  13   a ,  13   c . Specifically, the first longitudinal side  21  of the exterior surface  18   b  of the first curtain  18  is releasably attachable to the first attachment member  12   a , the second longitudinal side  22  of the exterior surface  18   b  of the first curtain  18  is releasably attachable to the third attachment member  13   a , the first longitudinal side  41  of the exterior surface  38   b  of the second curtain  38  is releasably attachable to the second attachment member  12   c , and the second longitudinal side  42  of the exterior surface  38   b  of the second curtain  38  is releasably attachable to the fourth attachment member  13   c . The releasable attachments of the longitudinal sides  21 ,  22 ,  41 ,  42  to the attachment members  12   a ,  12   c ,  13   a ,  13   c  are achieved through hook and loop fastening material. Each attachment member  12   a ,  12   c ,  13   a ,  13   c  has hook fastening material  15  affixed to the inner surface  120   a ,  120   c ,  130   a ,  130   c  thereof. Affixed to each longitudinal side  21 ,  22 ,  41 ,  42  is loop fastening material  16  complementary to the hook fastening material  15  affixed to the attachment members  12   a ,  12   c ,  13   a ,  13   c . The attachment of loop fastening material  16  to each longitudinal side  21 ,  22 ,  41 ,  42  is preferably along, or in the alternative relatively near, the lateral edges of the curtains  18 ,  38 . 
     The first curtain  18  has a second end  23  opposite the first end  19  and the second curtain  38  has a second end  43  opposite the first end  39 . As best shown in  FIGS. 2-3  and  5 - 7 , each second end  23 ,  43  is upturned such that each curtain  18 ,  38  has an upwardly opening pocket  25 ,  45  formed therein. Supported within the pocket  25  of the first curtain  18  is a first elongated rod  34  and supported within the pocket  45  of the second curtain  38  is a second elongated rod  35 . As is best shown in  FIG. 2 , even when the first rod  34  is substantially at its bottommost position, the second ends  23 ,  43  preferably remain upturned. Therefore, it can be appreciated that the second ends  23 ,  43  preferably never separate from one another and therefore are preferably attached to each other, such as by being sewn together. The height of the second ends  23 ,  43  is adjustable. As best shown in  FIGS. 2-3 , the height of the second ends  23 ,  43  determines the area of the opening  11  covered by the curtains  18 ,  38 . The attached second ends  23 ,  43  are preferably connected to a transverse take-up roller or spindle  31  mounted superjacent the opening  11 . The spindle  31  is preferably driven by a reversible motor  33  attached to a selected means of control. The attached second ends  23 ,  43  are preferably attached to a common take-up curtain  32  which is in turn attached to the spindle  31 . Alternatively, the second ends  23 ,  43  of each curtain may be directly attached to the spindle  31 . As the spindle  31  rotates, the take-up curtain  32  either wraps around or unwraps from the spindle  31 , altering the effective length of the take-up curtain  32  and thus the height of the attached second ends  23 ,  43 . The spindle  31  is preferably made of metal or durable plastic. 
     As noted above, supported within the pocket  25  of the first curtain  18  is a first elongated rod  34  and supported within the pocket  45  of the second curtain  38  is a second elongated rod  35 . Each elongated rod  34 ,  35  extends across the width of the opening  11  and is preferably at least as long as the second end of each curtain  18 ,  38 . The rods  34 ,  35  are preferably of equal size, shape, and material, preferably each made of solid or tubular pipe made of a durable material such as metal or fiberglass, which may be covered with flexible foam for safety. Preferably, the opposing ends of each elongated rod  34 ,  35  are captured within the channel members  12 ,  13  such that the rods  34 ,  35  are capable of rolling vertically within the channel members  12 ,  13  but are not capable of substantial movement in the horizontal plane. As best shown in  FIGS. 2-3 , the distance between the attachment members  12   a ,  12   c ,  13   a ,  13   c  of each channel member  12 ,  13  is preferably less than twice the diameter of each elongated rod  34 ,  35  such that the elongated rods  34 ,  35  may be positioned such that the second rod  35  is maintained at a height greater than the height of the first elongated rod  34 . As the spindle  31  rotates so that the take-up curtain  32  is unrolled therefrom, the height of the second ends  23 ,  43  is lowered, thereby lowering the pockets  25 ,  45  and elongated rods  34 ,  35  to allow the curtains  18 ,  38  to cover the opening  11 . As the curtains  18 ,  38  are lowered to cover a larger area of the opening  11 , the lowering elongated rods  34 ,  35  roll along the inside surfaces  18   a ,  38   a  of the curtains  18 ,  38  and urge the curtains  18 ,  38  against the attachment members  12   a ,  12   c ,  13   a ,  13   c . This force applied against the longitudinal sides  21 ,  22 ,  41 ,  42  of the exterior surfaces  18   b ,  38   b  pushes the loop fastening material  16  affixed thereto into the hook fastening material  15  affixed to the attachment members  12   a ,  12   c ,  13   a ,  13   c , thus causing a secure attachment between the curtains  18 ,  38  and the channel members  12 ,  13 . 
     As best shown in  FIG. 3 , because the second end  23 ,  43  of each curtain is upturned, the interior surface  18   a  of the first curtain is divided into two segments which face one another, while the segments of the exterior surface  18   b  face away from one another. Therefore, the upturned portion of the first longitudinal side  21  of the exterior surface  18   b  of the first curtain  18  faces the inner surface  120   c  of the second attachment member  12   c . Likewise, the upturned portion of the second longitudinal side  22  of the exterior surface  18   b  of the first curtain  18  faces the inner surface  130   c  of the fourth attachment member  13   c . While most of the exterior surface  18   b  of the first curtain  18  is separated from the second  12   c  and fourth  13   c  attachment members by the second curtain  38 , because the second elongated rod  35  is maintained at a height greater than the first elongated rod  34 , the lowest upturned portion of the exterior surface  18   b  of the first curtain  18 , which abuts the first elongated rod  34 , does not have such separation. When the first curtain  18  is at least partially raised, this portion lacking separation has loop fastening material  16  affixed thereto. To prevent the hook fastening material  15  affixed to the second  12   c  and fourth  13   c  attachment members from engaging the loop fastening material  16  affixed to the exterior surface  18   b  of the first curtain  18 , the hook fastening material  15  affixed to the second  12   c  and fourth  13   c  attachment members, and more preferably also to the first  12   a  and third  13   a  attachment members, is comprised entirely of downwardly facing hooks  15 , shown in  FIGS. 5-7 . A suitable hook for the hook fastening material is disclosed in U.S. Pat. No. 4,984,339 to Provost et al., incorporated herein by reference. 
     Hook and loop fastening material is well known in the art (e.g. VELCRO®). The hook fastening material is made of a plurality of small hooks preferably comprising nylon or polyester, most preferably extruded polyester for ultra-violet resistance, and the loop fastening material is made of a plurality of small loops preferably comprising nylon or polyester, most preferably nylon for strength. When the two materials are abutted, the small hooks of the hook fastening material engage the small loops of the loop fastening material. This interlocking of the small hooks with the small loops causes the fastening materials to form a secure attachment. Hook fastening material is typically made of multi-directional hooks that face in a plurality of directions, such as upwardly and downwardly. However, for the reasons explained below, the use of multi-directional hooks in the present dual curtain system is problematic. 
     In the event of an external force against the first curtain  18  whereby the pocket  25  of the first curtain  18 , with enclosed rod  34 , detaches from the first  12   a  and third  13   a  attachment members and makes contact with the second  12   c  and fourth  13   c  attachment members (see  FIG. 7 ), the contact between the loop fastening material  16  affixed to the first curtain  18  and the hook fastening material  15  affixed to the second  12   c  and fourth  13   c  attachment members would typically be momentary but for the engagement of the fastening materials  15 ,  16 . Through experimentation it has been determined that, where the hook fastening material is made of multi-directional hooks, the multi-directional hooks tend to engage the loop fastening material even on such momentary contact and hang up the curtain. The curtain must then be raised to a position above the hang up location and lowered again. However, experimentation has shown that this momentary contact is insufficient for hook fastening material made of only downwardly facing hooks to attach to the loop fastening material. Instead, the loop fastening material tends to bounce off or roll off the downwardly facing hooks and, consequently, the first curtain  18  will return to its proper position. 
     In addition, the attempt to address the hang up problem discussed in the “Background of the Invention” section whereby the mating hook and loop fasteners on each curtain and corresponding lateral side of each channel member were (1) reduced in width and (2) the mating hook and loop fasteners on one lateral side of a channel member were offset from the mating hook and loop fasteners on the opposite lateral side of the channel member becomes completely unnecessary with the use of only downwardly facing hooks of the present invention. Thus, the width of the mating hook and loop fasteners can be maximized (e.g., greater than two-fold the reduced hook and loop fastener width design discussed above) to create more hook and loop overlap and thus a more secure seal, and to avoid creases forming in the curtains. As a result, the present invention promotes a far superior seal and extends the life of the curtains in addition to the life of the hook and loop fastening material. 
     While the downwardly facing hooks  15  affixed to the inner surface  120   c ,  130   c  of each of the second  12   c  and fourth  13   c  attachment members of the present invention resist engaging the loop fastening material  16  affixed to the first curtain  18  based on momentary contact, it has been determined that the present invention achieves a sufficient seal between the downwardly facing hooks  15  affixed to the second  12   c  and fourth  13   c  attachment members and the loop fastening material  16  affixed to the second curtain  38 . The sufficiency of this seal is due to a longer period of contact between the loop fastening material  16  and the downwardly facing hooks  15 , as the loop fastening material  16  affixed to the second curtain  38  is unrolled adjacent to the downwardly facing hooks  15  and the loop fastening material  16  is pushed into the downwardly facing hooks  15  by the second elongated rod  35 . The downwardly facing hooks  15  allow the complementary loop material  16  to roll into the hook material  15  as the curtains  18 ,  38  are lowered, thereby sealing the curtains  18 ,  38  to the channel members  12 ,  13 . When the curtains  18 ,  38  are raised, the loop material  16  rolls out of the hook material  15 . Because the loop material  16  is rolled out, tearing of the loops is minimized. Consequently, additional benefits of using hook and loop fastening material having only downwardly facing hooks  15  is that the life of the hook and loop fastening material is greatly increased (e.g., ten-fold) over hook and loop fastening material having multi-directional hooks, and the noise associated with the loop material  16  detaching from the hook material  15  is greatly reduced, which may be critical in environments requiring low noise. 
     While only one form of the invention has been shown, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof. For example, the hook fastening material  15  can be affixed to a “floating” edge of flexible material attached at one end to the first and second channel members  12 ,  13 , as is disclosed in U.S. Pat. No. 6,138,739 to Crider et al., incorporated herein by reference.