APPARATUS AND METHOD FOR WINDLOCKING A BUILDING OPENING

Abstract: A track system for use in a windlocking apparatus is disclosed and claimed. One embodiment includes a housing piece and an interfitting piece. The housing piece includes a channel and the interfitting piece includes a key which slidingly mates with the channel. The housing piece and the interfitting piece each have flanges having smooth contours thereon. Another embodiment employs a track having a first piece and a second piece with the first piece having at least one groove therein and the second piece having at least one protrusion thereon. The protrusion of the second piece interfits with groove of the first piece interlocking the first and second pieces together.

Description: APPARATUS AND METHOD FOR WINDLOCKTNG A BUILDING OPENING Field of he Invention This application is a continuation-in-part of co-pending application serial number 09/644,924 filed August 23, 2000 which is a continuation-in- part of co-pending application serial number 09/520,845, filed March 8, 2000. The invention is in the field of windlocking a building opening to prevent the intrusion of unwanted air, fluid (typically water or sea water) and debris. During hurricanes and other high wind velocity storms, the breach of a building opening can cause great damage to the structure. If the building structure is not breached, then substantial damage can be prevented. Background ofthe Invention Many building codes are now requiring or will soon require hurricane shutters on all new homes built in coastal areas. Similar requirements for buildings other than homes are anticipated as well. The South Florida Building Code, 1994 Edition, requires that storm shutters shall be designed and constructed to insure a minimum of a one inch separation at maximum deflection with components and frames of components they are to protect unless the components and frame are designed to receive the load of storm shutters. The determination of actual wind loading on building surfaces is complex and varies with wind direction, time, height above ground, building shape, terrain, surrounding structures, and other factors. The American Society For Testing And Materials (ASTM) has promulgated a Standard Test Method For Structural Performance of Exterior Windows, Curtain Walls, And Doors By Uniform Static Air Pressure Difference and its designation is E330- 97 and was published April 1998. The test method requires that the person specifying the test translate anticipated wind velocities and durations into uniform static air pressure differences and durations. Durations are considered because most materials have strength or deflection characteristics which are time dependent. Testing under this method is performed in a test chamber which measures the pressure difference across the test specimen. Similarly, ASTM has declared a Standard Test Method For Water Penetration Of Exterior Windows, Curtain Walls, And Doors By Uniform Static Air Pressure Difference which includes a water spraying apparatus within the test chamber. See, ASTM designation E331-96. Leakage rate testing can be done under the ASTM Standard Test Method For Determining The Rate Of Air Leakage Through Exterior Windows, Curtain Walls And Doors Under Specified Pressure Differences Across The Specimen. See, ASTM designation E283-91. When a building envelope is breached devastating pressure differentials cause large amounts of damage. Kinetic energy due to the velocity ofthe fluid is proportional to the square ofthe velocity. Energy from the wind, therefore, pressurizes the interior of a home or other structure which in combination with the profile ofthe roof makes the roof, in effect, act like an airplane wing causing it to blow off the remaining structure. Windload and impact resistance requirements depend on the particular community promulgating the requirements. The American Society of Civil Engineers' Standard 7 is being increasingly used by public regulators in formulating requirements. In some areas of high probability for high wind occurrences, such as hurricanes, existing homes are required to upgrade windows and doors or add shutters and other protective devices to building openings to protect them. Conventional storm window protection as shown in U.S. Patent No. 4,065,900 to Eggert, U.S. Patent No. 4,069,641 to De Zutter and U.S. Patent No. 4,478,268 to Palmer are methods of attaching outer coverings to window or door openings. U.S. Patent No. 4,065,900 to Eggert discloses an apparatus for framing and fastening a secondary glazing pane which utilizes a hinge. U.S. Patent No. 4,069,641 to De Zutter discloses a storm window frame which utilizes double-faced tape to mount the storm window frame and, hence, the storm window. U.S. Patent No. 4,478,268 to Palmer discloses a hard flexible curtain door, a tensioned storage or wind-up drum, and channels in which the door resides. The door moves out ofthe channels under impact and is wound up to open for vehicle passage. U.S. Patent No. 4,126,174 to Moriarty, et al. discloses a tensioned flexible sheet storage roller, a guide roller and side seal guides. These coverings are normally clear flexible materials that must be installed and removed as needed or can be rolled and stored in a storage area above the window. These materials can be tinted to provide a reduction in sunlight transmission, but tinting would also reduce vision at night. These storm window coverings offer good thermal insulation, but offer minimal protection from high wind velocity pressures and wind borne debris. Further, these coverings are usually made of flexible polyvinyl chloride and will functionally deteriorate with time and must be replaced. The coverings that are of rolling construction must have adequate clearance between the guide rails and the sheet to prevent jamming ofthe sheet in the guide rails during opening and closing. U.S. Patent o. 4,294,302 to Ricke, Sr. discloses a security shutter and awning device for covering windows and doors. The device includes slats made from aluminum or other extrudable material of sufficient strength to protect against storms and/or vandalism. The shutter of Ricke, Sr. may be slidably mounted and pivoted so as to act as an awning. U.S. Patent No. 4,601,320 to Taylor discloses a pressure differential compensating flexible curtain with side edge sections which are sealingly engaged with channels. The first upper end ofthe curtain is attached to a curtain winding mechanism which includes a spring barrel. Taylor discloses an elastomeric curtain having plastic supports with rubber covers banded thereto. Alternatively the plastic supports may be high molecular weight plastic strips. The purpose behind the design ofthe supports is to minimize the friction of these supports enabling operation ofthe door/curtain with a high differential pressure across it. U.S. Patent No. 4,723,588 to Ruppel discloses a roller shutter slat which interlocks with the adjacent roller sheet slat. U.S. Patent No. 5,657,805 to Magro discloses a wind-resistant overhead closure with windlocks on the lateral edge portions ofthe intermediate and bottommost slats ofthe closure. First means to limit the lateral movement ofthe lateral edge ofthe intermediate potions and second means to limit the lateral movement ofthe endmost door portion are disclosed. Intermediate slats and endmost slats are provided. The '805 patent indicates in col. 2, lines 12 et seq. that it conforms with the South Florida Building Code, 1994 Edition, previously referred to hereinabove. Further, the '805 patent states that its teachings are applicable to both doors and windows. Windlocks can be added at the end of slats which will improve the resistance of multileaf shutters or doors to wind velocity pressures by transmitting the stresses on the continuous hinge area to the ends ofthe slat, to the guide system and finally to the jambs or building structure. In order for the windlocks to engage the guide track the slat must deflect a considerable amount. Normally clearance is allowed between the guide track and the windlock to keep the door from jamming during operation and the more clearance allowed the more deflection ofthe slats before the windlocks contact the guide track. Typically, these windlocks are larger in cross section than the slat profile and when the shutter or door deflects from high wind velocity pressures, the windlocks are designed to engage the same space in which the slats are guided. When storing a rolling multileaf shutter or door equipped with windlocks, additional room is needed because the depth ofthe windlock is larger than the slat profile, the diameter ofthe storage area increases dramatically. In these designs, clearance between the windlock and the track must be allowed to prevent the windlocks from jamming and care must be taken when operating shutters or doors in a wind because the windlocks will sometimes jam as the product deflects. U.S. Patent No. 5,445,902 to Lichy discloses a damage minimizing closure door somewhat similar to U.S. Patent No.4,478,268 to Palmer. The Lichy '209 patent discloses a flexible curtain and a guide for receiving and guiding the side edges ofthe flexible door during vertical movement. A counterbalancing power spring is associated with the door to assist in raising and lowering the curtain. Side edges ofthe curtain separate from the guide assembly upon being impacted by an externally applied force such as a vehicle. U.S. Paten No. 5,482,104 to Lichy discloses in Fig. 17 thereof, a flexible curtain and double windlocks which breakaway from the channel upon the application of excessive force to the curtain. See, col. 7, lines 33 et seq. U.S. Patent No. 5,131,450 to Lichy discloses in Fig. 6 thereof a double edged guide and a curtain edge with two loose portions sewn to the transverse curtain. See, col. 6, lines 21, et seq. U.S. Patent No. 5,232,408 to Brown discloses a flexible tape drive system wherein the tape is relatively rigid and it is driven by a toothed cog to provide both push and pull capabilities. U.S. Patent No. 5,048,739 to Unoma, et al. illustrates a conical toothed drive paper feeder. Conventional storm curtains without windlocks to engage into guides will pull out ofthe guides. This is especially true of wider curtains where they might be partially lowered for shading purposes without attaching storm bars required for storm protection. If, while lowering, or subsequent to lowering, wind forces exist that are significant but in no way threatening, the storm curtains typically escape from the guides due to excessive deflection ofthe slats. When this occurs, the slats become damaged as well as the facade surrounding the guide area becomes damaged as the ends ofthe slats typically rake the surrounding area in the process of escaping. The majority of applications for conventional storm curtains do not use windlocks. Rather than using windlocks, the problem of excessive curtain deflection which causes the curtain to escape from the guides is addressed with the use of storm bars. Storm bars, however, have disadvantages. Storm bars create a passive system i.e. in the event of a severe storm they need to be taken out of storage and attached in predetermined locations across the span of the curtain. A wide curtain may require as many as three sets of storm bars. Sets consist of two bars in close proximity to each other in such a way as the curtain passes between the two bars. This addresses deflection that occurs in both positive and negative directions. Positive deflection is in the direction ofthe building and negative deflection is away from the building. At each storm bar location, brackets must first be attached to the floor, soffit and sills. Depending on the surrounding construction materials, secure locations are often difficult to find. After the brackets are attached to the building, the next step is to attach the storm bars to the brackets. Care must be taken to number and code the brackets to the matching storm bar, otherwise the pre-drilled holes for the bolts will not line up with the holes in the storm bars. Also, care must be taken to match and code the storm bars to their various locations since even a slight variation in the bar length causes the holes in the storm bar to misalign with the pre-drilled holes in the building facade. Also, these pre-drilled holes in the facade are permanent and cause problems aesthetically when the storm bar brackets are removed. Given the problems associated with escaping storm curtains, the building owner faces a dilemma when moderate storms are predicted such as severe summertime thunder storms. The daunting task of attaching the storm bars cannot be justified for every storm. Because the risk of damaging the storm curtains without attaching the storm bars is so great, the curtains are not utilized in moderate storms. Therefore, the building owner has a protection system that is either "on or off," "on" meaning storm bars and curtains and "off meaning nothing at all. Conventional storm curtains do not have windlocks to prevent the slats from escaping the guides because windlocks have a larger cross section than that ofthe slat and using windlocks increases storage coil diameter which is a major limiting factor. With windlocks ofthe related art, storm curtains have a tendency to bind in the guides/tracks when being lowered because ofthe deflection ofthe curtain in moderate wind conditions. Enough friction is created, windlock to the inside edge of he guide, to cause the curtain to become obstructed and create unwanted accumulation of slats in the coil storage area. Additionally, adding windlocks to the ends of slats is very labor intensive and creates many more parts to drill and attach. The instant invention addresses these three issues. The first issue with conventional storm curtains, that being an increase in coil storage requirement, is addressed by utilizing an interrupt formed on the ends ofthe tension rods of the instant invention which does not increase the requirement for coil storage when the curtain is stored. The second issue regarding binding ofthe curtain is addressed by the instant invention since the tracks are mounted at a divergent angle with respect to each other and contact with the interrupts in the rod and the "J-shaped" channel does not occur until the guide is in a fully closed position minimizing friction. Further, in the instant invention, unwanted accumulation in the coil storage area does not occur and the drive system is able to generate downward closing forces that overcome minimal friction that may occur between the interrupt and the "J-shaped" channel. Finally, regarding the issue of windlocks being labor intensive, the interrupts formed near the ends ofthe rods in the instant invention are made with a single stroke of a press after the rods are inserted into the curtain and, as such, do not make the windlock system labor intensive. Summary ofthe Invention The instant invention uses light weight materials that have stiffness in the direction ofthe opening and closing but will bend around a radius as small as 0.5 inches. This strengthens the curtain by uniformly spreading the stresses developed by wind velocity pressure or impact over the width ofthe curtain and transferring the stresses to the track and to the structure ofthe building. The invention adds tension to the elements ofthe curtain in the direction along its width or perpendicular to the force that is created by wind velocity pressure or impact from debris. The tension is directly proportional to the wind velocity pressure or impact from debris. Angled guide tracks may be used that tension the curtain when the curtain is closed without jamming the curtain in the guide tracks. Metallic, non-metallic materials (or a combination of both) may be used and they may be and can be opaque or transparent. The windlock feature ofthe instant invention is incorporated into the curtain without affecting the thickness ofthe curtain and therefore does not affect the size ofthe storage area. The mass ofthe curtain is low allowing precise control of raising and lowering the curtain with a small power source and can be battery powered. Materials such as aramid fibers may be used thus making the curtain bullet proof. An apparatus and method for windlocking a curtain covering and protecting an opening in a building is disclosed and claimed. The windlocking curtain resides to the exterior ofthe window, door or other opening and protects it from the intrusion of air, water or debris. In its upper position the windlocking curtain permits normal use ofthe opening and in its lower position it secures the opening. A flexible corrugated curtain has tension rods therethrough and the tension rods run in tracks on each side ofthe curtain and necessarily on each side ofthe opening. Interengagement ofthe tension rods with the tracks is accomplished by deformations in the rods that are referred to as interrupts. In one embodiment the rods are successively longer from top to bottom ofthe curtain and their interrupts matingly wedge with angled tracks to secure the curtain. In another embodiment the interrupts matingly engage parallel tracks upon the application of force due to wind, fluid (usually water or sea water) or debris. In another embodiment tension rods and interrupts are not used or necessary and a flap on the edges of a three-ply flexible curtain engage the interior ofthe side tracks absorbing shocking and sealing the opening. A method for securing the opening utilizing the apparatus is also claimed which provides top, bottom and side securement. The flexible curtain comprises part of a curtain system for covering an opening in a building. A frame is affixed to an opening in a building. A flexible, corrugated curtain has a plurality of rods extending through some of the corrugations ofthe curtain. Preferably the rods, sometimes referred to as the tension rods, are rectangular in cross-section so as to provide maximum strength ofthe rod. Other cross-sectional sizes may be used. Angled tracks are provided in one embodiment which mate and wedge with angled interrupts when the curtain is in its second, closed position. When the curtain is open, it is in its first position and resides primarily on a counterbalanced windup reel. Each successive tension rod is longer than the prior rod so as to engagingly wedge with the angled tracks. The tracks are angled away from each other when the top point ofthe tracks are taken as the reference points. In other words, the tracks are at a divergent angle and get farther apart at the bottom. The tension rods include a deformed portion sometimes referred to as an interrupt. The purpose ofthe interrupt is to matingly engage the tracks. In the embodiment which employs tracks which diverge from the top to bottom, the preferred divergent angle is one-half of one degree. Specifically, each track is diverging with respect to an imaginary vertical line at an angle of one- half degree making the total divergence for two tracks equal to one degree. One-half to one degree divergence from vertical per track (one to two degree divergence for both tracks) has been found to work well. Larger divergence angles require necessarily deeper tracks and larger interrupts particularly if a long building opening is to be protected. Those skilled in the art will readily realize from reading this disclosure that other angles may be used depending on the size ofthe opening to be covered. Corrugated flexible curtain is used in one embodiment as stated above and slits therein may be employed in the face ofthe curtain to improve the flexibility for storing on the counterbalanced wind-up reel. In regard to storage ofthe curtain and tensioning rods, the deformations ofthe tensioning rods (interrupts) do not increase the space required for storage because the thickness ofthe tension rod is not increased in the direction ofthe radii ofthe wind-up reel. Operation ofthe flexible curtain is enhanced by using divergently separating track as the occurrence of jamming is minimized. All ofthe tension rods are designed to engage the angled tracks at approximately the same time creating a wedge effect since the interrupts are deformed at a mating angle which matches the angle ofthe track. Another embodiment ofthe invention employs parallel tracks and the tension rods do not engage the tracks except during times when they are loaded. In this embodiment the tension rods are all the same length and when the curtain is closed in its second position the lips ofthe interrupt do not engage the track. When the wind velocity becomes sufficiently high, the curtain deflects and pulls the mating surfaces ofthe interrupts into engagement with the track. Another embodiment ofthe invention employs tension rods having a ninety degree radius at the ends thereof and eliminates the need for interrupts. It is the ninety degree radius which engages the angled/parallel tracks. Rectangular apertures exist in the flexible corrugated curtain for engagement with teeth of a driving gear or gears. The gears, under resistance of a counterbalance spring affixed to the wind-up rod, drive the curtain from a first, open position to a second, closed position. All embodiments disclose rectangular curtains. Standard window dimensions are 30 to 36 inches wide and 30, 38 or 54 inches long. However, longer and wider openings can be secured with the embodiments ofthe invention disclosed herein. Corrugated curtains can be driven with a single gear or with dual gears. Openings in buildings of all sizes may be protected using the principles ofthe invention. Alternatively, a driven adapter rack and/or an adapter rack and a gear may be simultaneously used to drive the tension rods. Another embodiment employs a flexible curtain comprising three-plies laminated together. The plies may be laminated together under the influence of heat and pressure. Additionally adhesive may be used to secure the plies together. Two outer plies or sheets are polymeric and the inner ply is woven. A living seal is formed on the edges ofthe curtain by folding the edges ofthe curtain back on the curtain itself. The folded portion is secured by stitching with thread, or by adhesive, or by heat fusing, or by ultrasonic welding. Only a portion ofthe folded flap is secured. Preferably two-thirds (2/3) ofthe folded flap is secured to itself and one-third (1/3) remains free. When the three-ply curtain is tensioned under the influence of wind or debris loading, for instance, the folded portion engages the interior ofthe track which houses the folded portion preventing its escape therefrom. Further, the folded flap provides a total seal which is sometimes referred to herein as a living seal. The free portion ofthe flap provides a shock absorber which cushions the frame against time variant forces which may be applied due to fluctuating wind and/or debris. The three ply curtain may also be used with angled track by slitting the outer face ofthe three ply curtain. The slitting provides a loose flap which engages the track. Cylindrical apertures reside in the folded portion of said three-ply curtain and the drive cog interengages the apertures for raising and lowering the curtain against the force ofthe counterbalance spring. Preferably, there is a folded portion on each side ofthe curtain residing in its respective track and being driven by its respective drive cog. Conically shaped cogs fit the apertures well and, additionally, the apertures may be fitted with eyelets. A bowed bottom bar is secured within a folded portion ofthe curtain and guides the curtain into a slot. In other words, the curtain is slightly longer at its edges than in the middle such that as the curtain is coming down for securement in the second, closed position the sides enter the retaining slot first. If the curtain is being closed during a strong wind event, the middle ofthe curtain may be deflected slightly inwardly but the side portions are not because they are within the tracks which are directly aligned with (above) the retaining slot. This enables the bottom bar to begin seating in the retaining slot at the side edges and guide the bottom bar into place. Additionally, the weight ofthe bar assists in positioning it in place in the retaining slot. Additionally, a living seal formed by a flap extending from the stitched or heat sealed bottom bar may be employed in a modified retaining slot sometimes referred to herein as a storage slot. Another embodiment ofthe bottom bar interengages a sill or bottom member having a seal therein. The bottom bar may be affixed to the bottom ofthe curtain by any one of several known fastening devices such as rivets, bolts and threads, and the like. The curtain system covers a window, door or other opening a building. The curtain system may reside to the exterior ofthe window, door or other opening or it may reside to the interior ofthe window, door or other opening. Accordingly, it is an object ofthe present invention to provide a low cost and light weight flexible curtain which develops transverse (side to side when viewed from the front) tension each time the curtain closes. It is a further object ofthe present invention to provide a curtain system which uses a light weight counterbalance because ofthe lightweight construction ofthe curtain. It is a further object to provide a curtain having windload and impact resistance which is always active when the curtain is closed and requires no other action by the user in the event of a high velocity wind occurrence. It is a further object to provide a curtain which will not jam and cause damage to the curtain during operation even if operated during high wind occurrences. It is further object to provide a storm curtain which stores within standard wall thickness found in the United States. It can be incoφorated into the window frame in such a way that the storm curtain does not require additional framework or cover for protuberances created by the larger storage coil diameters typical of conventional storm curtains. It is a further object ofthe present invention to provide a curtain system which resides to the exterior or the interior ofthe window, door or other opening in a building. It is a further object to provide a low maintenance storm curtain. Conventional storm curtains require periodic high pressure washing especially along coastal areas where they are exposed to salt spray and blowing sand. Conventional storm curtains are designed so that the longitudinal edges ofthe slats telescope into each other approximately three-eighths inch (3/8") to one- half inch (Yz") as shown in U.S. Patent No. 4,173,247 to Prana and U.S. Patent No. 5,322,108 to Hoffman. The telescoping portion ofthe slat is exposed when the storm curtain is partially closed, typically for sun control, and because ofthe weight ofthe slat suspended below, the slats will be extended from each other. When salt spray and sand accumulate on this portion ofthe surface ofthe slat, abrasion and friction will interfere with slat to slat telescoping. If the slats are not cleaned and pressure washed periodically, the lower slats usually start to malfunction first since they have the least gravitational force to cause separation. If this separation or telescoping does not occur and the slats enter the coil storage area they will be put into a severe bind and as a consequence, become damaged. Telescoping slats develop more beam strength when the longitudinal edges ofthe slats are telescoped into each other when fully closed. However, the maximum allowable radius requirement for the curtain to coil within the allocated storage area cannot be met unless the slat edges are fully extended from each other as they begin to articulate into the coil storage position. In the instant invention, the outside surface consists of a smooth polymeric material with no requirement to telescope. As such, there is no opportunity for salt spray and sand to accumulate in irregular surfaces. It is a further object of this invention to provide a smaller storage area. Another advantage ofthe instant invention, unlike conventional storm curtains, is that the instant invention becomes taut from top to bottom when in a closed position. For this reason there is no chatter, banging or rattling that exists with conventional storm curtains in buffeting winds. Further, when the embodiment ofthe living seal is employed, the loose or free portion ofthe folded flap or strip absorbs shock and therefore does not transmit it to the surrounding frame. This will make a quieter system with low or no maintenance. Still another advantage ofthe instant invention is that the storm curtain is directly linked to drive gears and a drive shaft which are engaged into perforations pierced into the curtain and essentially (but not actually) place the gear teeth in contact with the metal tension rods lodged in the corrugated curtain which, when activated, cause the curtain to be raised and lowered. The tension rods are completely sealed with respect to contamination by the corrugated material. In the embodiment ofthe three ply curtain, it completely seals against the intrusion of wind borne salt and debris. Another advantage ofthe instant invention is that the storm curtain can be pre-installed into the window frame at the factory as a single unit. The sub-contractor normally involved in the installation of storm curtains is no longer required. Another problem frequently encountered and avoided with the instant invention is related to the typically varied conditions prevalent on job sites. With a wide range of window configurations depending on the manufacturer and varied contractor preferred framing methods and sill details, these variations often complicate the installation of storm curtains. This can greatly increase the cost of installation where additional re-framing may be required or where other modifications need to be made so the storm curtain can be installed correctly. In the instant invention, the storm curtain is pre- installed into the window framework and these problems do not exist. Another advantage ofthe instant invention is that since the interrupts pressed (deformed) into the metal rods embedded in the curtain are engaged into the "J-shaped" track, the curtain cannot escape or "blow out". Another advantage ofthe instant invention is that the track comprises two pieces. This enables easy manufacture ofthe pieces while providing a strong track when the pieces are assembled together. When the wind, debris and water tensions the curtain either in a positive direction or a negative direction, a strong and stable track affixed to the building adjacent an opening is required. Positive deflection is in the direction ofthe building and negative deflection is away from the building. The two-piece track construction is interlocked together and may be screwed, welded, tack-welded, ultrasonically welded if made from plastic, bound by adhesive, and/or riveted. In this way the two piece construction provides a strong and stable track which is necessary to absorb the reaction forces ofthe wind, debris and water which impact the curtain. Instead ofthe two-piece frame being mechanically fastened together through the use of fasteners, it may be secured together through a sliding interlocking fit. The interlocking fit has the advantage of continuous engagement over the length ofthe track. Manufacture ofthe two pieces is thus greatly facilitated since it is much easier to manufacture them separately and the interlocking fit provides great strength. Although the preferred material of the track is metal such as aluminum, it may be made from plastic. It is a further object and advantage ofthe instant invention to provide a track which has gentle contours which engage the curtain as it is tensioned such that the curtain is not cut or torn. During violent wind conditions the kinetic energy ofthe wind will cause the curtain to suddenly engage the track. The track includes contours which engage the curtain so as to minimize cutting ofthe curtain under loaded conditions. Additionally, the contours of the track seal against a coating on the flexible curtain. The flexible curtain is a polymeric material and it may be reinforced with polyester. Further, the flexible curtain may be coated with a silicone or polyvinyl chloride or the like. The coated surface is a smooth surface which engages the contours ofthe track under loaded conditions to provide a seal. A better understanding ofthe objects and advantages ofthe invention will be had when reference is made to the Brief Description of the Drawings, Description ofthe Invention and Claims which follow hereinbelow. Brief Description ofthe Drawings Fig. 1 is a front plan view of a seventy-two inch flexible curtain having a track at one degree (1°) from vertical. Fig. 2 is an exploded view of a portion of Fig. 1. Fig. 3 is an exploded view of a portion of Fig. 2. Fig. 4 is a composite view illustrating a reduced scale view of Fig. 1 together with reduced scale views of Figs. 4A and 4B. Fig. 4A is a cross-sectional view ofthe flexible curtain illustrated in Fig. 1 taken along the lines 4A-4A. Fig. 4B is a cross-sectional view ofthe flexible curtain and window illustrated in Fig. 1 taken along the lines 4B-4B. Fig. 4C is an enlarged cross-sectional view of Fig. 4A illustrating the application ofthe invention to protect a window opening. Fig. 4D is a cross-sectional view similar to that of Fig. 4A illustrating the wind-up reel in greater detail for use in connection with the three-ply flexible curtain and the cog drive. Fig. 5 is a schematic view ofthe seventy-two (72") inch curtain illustrating a one degree (1°) runout ofthe tracks and tension rods. Fig. 6 is a front view of a seventy-two inch (72") curtain similar to that illustrated in Fig. 1 except that the left side and right side tracks are parallel to each other and, additionally, illustrates that the tension rods do not have any runout. Fig. 7 is an enlarged portion of Fig. 6. Fig. 8 is a schematic representation ofthe flexible curtain, track and tension rods ofthe embodiment of Fig. 6. Fig. 9 is a front view of a thirty-eight inch (38") curtain illustrating a one-half degree (/ °) runout ofthe tension rods. Fig. 9A is a view similar to that of Fig. 1 illustrating a one-half degree (Vi 0 ) runout ofthe tracks, interrupts and tension rods. Fig. 9B is an enlarged portion of Fig. 9 illustrating the tension rods, flexible curtain and the drive apertures in the curtain. Fig. 9C is a perspective view of a portion ofthe curtain having a one- half degree runout further illustrating the corrugated flexible curtain and the interrupts mating with the frack restraining movement ofthe flexible curtain toward the window. Fig. 10 is a schematic ofthe thirty-eight inch (38") curtain illustrating a one-half degree (V2 0 ) runout ofthe frack, interrupts, and tension rods. Fig. 11 is a top view of a left side frack like that of Fig. 1 illustrating the top rod in its fully down position engaging the track. Fig. 11 illusfrates a cross-sectional view ofthe top ofthe track which has a one degree (1°) runout. The runout, however, is not illustrated in this drawing. Fig. 11A is a front view ofthe left side frack and the top rod illustrated in Fig. 11. Fig. 1 IB is a top view of a left side frack like that of Fig. 9 A illustrating the top rod in its fully down position engaging the track. Fig. 9A illustrates a cross-sectional view ofthe top ofthe track which has a one-half degree (V∑* 0 ) runout. The runout, however, is not illustrated in this drawing. Fig. 1 IC is a front view ofthe left side track and the top rod illustrated in Fig. 11B. Fig. 12 is a top view of a left side frack like that of Fig. 1 illustrating the bottom rod in its fully up position entering the track. Fig. 12 illusfrates a cross-sectional view ofthe top ofthe track which has a one degree (1°) runout. The runout, however, is not illustrated in this drawing. Fig. 12A is a front view ofthe left side track and the top rod illustrated in Fig. 12. Fig. 12B is a top view of a left side frack like that of Fig. 9 A illustrating the bottom rod in its fully up position entering the track. Fig. 12B illusfrates a cross-sectional view ofthe top ofthe track which has a one-half degree (V2 0 ) runout. The runout, however, is not illustrated in this drawing. Fig. 12C is a front view ofthe left side track and the top rod illustrated in Fig. 12B. Fig. 13 is a cross-sectional view ofthe bottom bar sealingly engaging the bottom sill which is affixed to the frame ofthe structure. Fig. 13 A is a cross-sectional view of a three-ply flexible curtain affixed to a bottom bar. Fig. 13B is a cross-sectional view of a three-ply curtain with a bottom bar secured therein by adhesive or lamination. Fig. 13C is the same as Fig. 13B except stitching is used to secure the bottom bar. Fig. 13D is a front view ofthe vertically bowed bottom bar alone. Fig. 14 is a perspective view of a tension rod. Fig. 15 is an enlarged portion ofthe tension rod illustrated in Fig. 14. Fig. 16 is another enlarged view of a portion of a tension rod. Fig. 17 is a view ofthe end portion of a tension rod illustrating a circular in cross-section tension rod. Fig. 18 is a plan view of a tension rod. Fig. 19 is a side view of a tension rod illustrating the interrupts therein. Fig. 20 is a perspective view ofthe track. Fig. 21 illustrates a plan view of one ofthe tracks. Fig. 22 is a cross-sectional view of a three-ply curtain and track taken along the lines 22-22 of Fig. 28. Fig. 22A is a cross-sectional view similar to the view of Fig. 22 further illustrating eyelets in the apertures. Fig. 22B is a cross-sectional view identical to Fig. 22 except the cross hatching ofthe polymeric plies is not illusfrated so as to better depict the curtain. Fig. 22C is a cross-sectional view identical to Fig. 22A except the cross hatching ofthe polymeric plies is not illustrated so as to better depict the curtain. Fig. 23 is a cross-sectional view of a three-ply curtain and track with the curtain taken along the lines 23-23 of Fig. 7. Fig. 23 A is a cross-sectional view similar to the view of Fig. 23 except the cross hatching ofthe polymeric plies is not illustrated so as to better depict the curtain. Fig. 23B is similar to the view shown in Fig. 23 except the curtain is shown under the influence of pressure "P." Fig. 23 C is similar to the view shown in Fig. 23 A except the curtain is shown under the influence of pressure "P." Fig. 24 is a cross-sectional view of a three-ply curtain together with a semi-rigid strip affixed to one edge thereof. Fig. 25 is a cross-sectional view of a three-ply curtain similar to the view of Fig. 23 with the curtain under the influence of a force, for example, a high velocity wind. Fig. 26 is a cross-sectional view of a three-ply curtain having a folded edge and illusfrating two polymer sheets and a woven sheet secured together with adhesive. Fig. 26A is a cross-sectional view of a three-ply curtain having a semirigid strip affixed to one edge thereof by means of adhesive. Fig. 26B is a cross-sectional view of an embodiment employing two plies of polymeric material secured together with a fiber reinforcement. One ply ofthe polymeric material has been slit to engage the frack when the curtain is under tension. Fig. 27 is a rear view ofthe three-ply flexible curtain illustrating a semi-rigid strip applied to both edges ofthe curtain. Fig. 28 is a front view of a three-ply curtain being driven by a gear having conical teeth or cogs. Fig. 28A is a cross-sectional view taken along the lines 28A-28A of Fig. 28 illustrating the drive roller. Fig. 28B is a cross-sectional view taken along the lines 28B-28B of Fig. 28 illustrating counterbalanced springs which tension the curtain between the drive cogs and the storage reel. Further, securement ofthe springs to a fixed structure is shown in this view but is not shown in Fig. 28. Fig. 28C is a view similar to Fig. 28 further illustrating a bowed bottom bar. Fig. 28D is a perspective view illustrating the bottom bar being guided by the tracks into the storage slot. Fig. 28E is a front view of a flexible curtain and window in a building illusfrating the curtain in its first, open position. Fig. 28F is a front view of a flexible curtain and window in a building illustrating the curtain in its second, closed position. Fig. 29 is a side view of Fig. 28. Fig. 30 is a perspective view ofthe chain (drive adapter rack) and gear drive. Fig. 31 is a perspective view of an adapter rack illusfrating tensioning rods having a ninety degree (90°) bend at the edges thereof. Fig. 32 is a perspective view of an adapter drive. Fig. 33 is a perspective view ofthe gear drive. Fig. 34 is another embodiment ofthe invention illusfrating pressure from the wind applied to the glass window which resides exteriorly to the flexible curtain. Fig. 35 is a perspective view of another embodiment ofthe track in which the frack includes two pieces. Fig. 36 is a cross-sectional view ofthe frack illustrated in Fig. 35 together with the flexible curtain having semi-rigid strips affixed thereto. Fig. 36A is an enlarged portion of Fig. 36 illustrating a gap between the semi-rigid strip and the frack. Fig. 36A also illustrates the contours ofthe frack. Fig. 37 is a cross-sectional view ofthe frack together with the curtain under the influence of a positively directed pressure. Fig. 37A is an enlarged portion of Fig. 37 illustrating the curtain engaging the frack. Fig. 38 is a cross-sectional view ofthe curtain and the frack under the influence of a negatively directed pressure. Fig. 38A is a cross-sectional view of an enlarged portion of Fig. 38 illusfrating the track and the curtain engaging the track. Fig. 39 is a cross-sectional view of a two-piece track construction wherein one piece interfits with the other piece. Fig. 39 A is a cross-sectional view ofthe housing piece ofthe two-piece interfitting track system. Fig. 39B is a cross-sectional view ofthe interfitting piece ofthe two piece track system. A better understanding ofthe drawings will be had when taken together with the Description ofthe Invention and the Claims which follow hereinbelow. Description ofthe Invention The first embodiment is the combination of a curtain composed of corrugated nonmetallic material with metallic rods embedded in the corrugations. Inward from the ends ofthe metallic rods, also known as the tension rods, interrupts are formed which maintain the cross-sectional area of the rod. This provides for uniform tensile strength ofthe rod. The rod lengths uniformly increase from rod to rod from the top ofthe curtain toward the bottom ofthe curtain. The ends ofthe rods form an angle with respect to the corrugated nonmetallic material ofthe curtain. The interrupts in the rods have a matching or corresponding angle to the angle ofthe tracks. This angle allows the curtain assembly to wedge when the curtain is closed. The tracks have a "J-shaped" portion with one leg angled back from the mouth ofthe "J" to form a mating interrupt with the interrupt on the rod such that as tension is developed in the rod due to wind velocity pressure or windborne debris, the "J" will close on the rod with a clamping action transferring the stress load to the tracks and then to the opening frame and onto the building structure. The curtain is additionally supported by a counterbalance drive tube that will assist in returning the curtain to a rolled up stored position. The nonmetallic portion ofthe curtain can also be made from sheets of material laminated together capturing and positioning the metallic rod. These sheets can be fused, glued, stitched, or attached by other fastening means to prevent the rotation ofthe rod in relationship to the curtain. The metallic rods preferred in this curtain can be round or polygonal in shape. The more polygonal, the more retention needed to hold the rod in position. Conversely, the less polygonal or the fewer number of sides in the polygon, then less retention is required. A version of this embodiment can be used on conventional rolling door systems where the slats are cut in uniformly, progressively longer lengths from the top ofthe door to the bottom ofthe door with standard windlocks alternately attached to the slat ends and the guide track deepened to the longest slat and set at a matching angle where the slats are uniformly placed in tension when the door is closed. The second embodiment ("parallel" embodiment) is a combination of a curtain composed of corrugated nonmetallic material with metallic rods embedded in the corrugations. Inward from the ends ofthe metallic rods, interrupts are formed in the tension rods which maintain the cross-sectional area for uniform tensile sfrength ofthe rod. Rod length is uniform from rod to rod, from the top ofthe curtain toward the bottom ofthe curtain, so that the ends ofthe rods are aligned parallel to the corrugated nonmetallic material of the curtain. A guide track system is employed that has vertical guide tracks that are parallel to the edge ofthe curtain. The guide tracks have a "J-shaped" end portion with one leg angled back from the mouth ofthe "J" to form a mating interrupt with the tension rods such that as tension is developed in the rod, the "J" will close on the rod with a clamping action. The curtain is supported by a counterbalanced drive tube that will assist in returning the curtain to a rolled up position. Further, the curtain is taut between the drive tube and the wind-up reel. The profile ofthe corrugated nonmetallic material is such that the front and back faces are in continuous contact allowing the curtain to be driven down without jamming or binding. The stored portion of the curtain has a tensioning device (i.e., a counterbalanced spring) to prevent the curtain from resisting movement as the diameter ofthe stored curtain reduces. A third embodiment employs a flexible curtain comprising three plies laminated together. These plies can be fused, glued, stitched or attached by other fastening methods. Two outer plies or sheets are polymeric. The inner ply is woven. A living seal is formed on the edges ofthe curtain by folding the edges of the curtain back on the curtain itself. The folded portion is secured by stitching with thread, by adhesive, or by heat fusing or by ultrasonic welding. Only a portion ofthe folded flap is secured, preferably two-thirds (2/3) ofthe folded flap is secured to itself and one-third (1/3) remains free. Under tension, this free portion ofthe folded flap seals and cushions the shock caused by the wind or airborne debris. Under the tension the free portion ofthe flap engages the guide frack. The three ply flexible curtain is driven by a cog wheel having conically shaped cogs which drive apertures located along the edges ofthe flexible curtain of this embodiment. Another version of this invention is a curtain employing a flat sheet of flexible material. It has grooves cut into one face that serve as an interrupt to a mating edge ofthe "J-shaped" frack or of a frack having another shape. Inward from the edges ofthe sheet, grooves at the same angle as track are cut into the curtain such that the grooves at the top ofthe curtain are closer together than they are at the bottom ofthe curtain. The guide tracks are then placed at the same angle to place the curtain in tension when the curtain is in the closed position. The grooves create a loose flap which engages the track when the curtain is all the way down in its second position. Fig. 1 is a front plan view of a 72" flexible curtain having tracks which are 1° from vertical. The entire curtain is not depicted in Fig. 1 because resolution would decrease. Put another way, the tracks are at a 1° angle from the edges ofthe corrugated curtain. Reference numeral 100 indicates generally the 72" flexible curtain. The curtain may be driven by motor 101 or by a pulley 102 as determined by a coupling 103 which may engage either the motor or the pulley as a source of energy for raising and lowering curtain 115. Curtain 115 is a rectangular corrugated nonmetallic curtain. Apertures 116 reside in the left-hand portion ofthe corrugated curtain and apertures 117 reside in the right-side portion ofthe corrugated curtain 115. Left-side track 111 is affixed to the frame or building structure as is right-side track 112. Reference numeral 113 is spaced leftwardly of frack 111 and reference numeral 113 denotes the bottom portion ofthe left-side frack 111. Reference numeral 114 illustrates the bottom portion ofthe right-side frack 112 and it too indicates a runout rightwardly with respect to the right side frack 112. It will be noticed that Fig. 1 depicts the first several tension rods and interrupts and the last several tension rods and interrupts. Interrupt 121 is near the top ofthe curtain. Interrupts 122 and 127 are near the bottom left side of the curtain. Tension rods 123 and 124 are shown entering the left side ofthe curtain traversing through the curtain in corrugated sections thereof and extending rightwardly through the curtain. It will be observed that tension rod 123 has a left side interrupt 122 and a right side interrupt 125. A plurality of slits 126 are indicated in Fig. 1 to enhance the flexibility ofthe curtain. Gears 119 and 120 are viewed in Fig. 1 for driving apertures 116 and 117 in the flexible curtain 115. A front view of bottom bar 118 which engages a sill/receptacle not shown in Fig. 1 is illusfrated therein. Referring still to Fig. 1, shaft 104 is supported by bearings 105 and 106. Curtain 115 extends onto windup reel 107 which is a counterbalanced windup reel. Supports 108 and 109 support the windup reel 107. Platform 110 which is interconnected to the opening in the building supports the structure generally. Fig. 2 is an exploded view of a portion of Fig. 1. Referring to Fig. 2, reference numeral 200 generally represents the enlarged portion of Fig. 1. Track 111 is shown in a cross-sectional view. The outer edge 201 and the intermediate support 202 of frack 111 are shown. Mating surface 203 ofthe "J-shaped" portion 204 of frack 111 are also shown. Mating surface 203 on the "J-shaped" portion 204 of frack 111 are shown in better detail in Fig. 3. Fig. 3 is an exploded view of a portion of Fig. 2. First interrupt 205 is illustrated in Figs. 2 and 3 and mating point 206 is also illustrated in both figures. Referring to Fig. 3, interrupt 205 includes a surface which engages the mating surface 203 of track 111. It must be kept in mind that track 11 is angling downwardly and leftward when viewing Figs. 2 and 3 such that the track and the interrupts are angled at a 1° angle with respect to the left side portion ofthe left side 220 ofthe curtain 115. The second interrupt 207 is illustrated with mating surface 208 which engages mating surface 203 on the "J-shaped" portion 204 of track 111. Similarly mating surface 209 of interrupt 210 engages mating surface 203 of frack 111. Reference numeral 211 indicates the end of interrupt 205. Referring to Fig. 3, reference numeral 212 indicates the beginning ofthe interrupt ofthe first tension rod near curtain 115. Similarly the runout ofthe rods and interrupts can be viewed when reference is made to reference numeral 213 which is the beginning ofthe interrupt ofthe third tension rod ofthe curtain. Reference numeral 213 "points" to a place further leftwardly. The 1° runout ofthe track, interrupts and the ends ofthe rods are illusfrated in Fig. 5. Fig. 4 is a composite view illusfrating a reduced scale view of Fig. 1 together with reduced scale views of Figures 4A and 4B. Fig. 4A is a cross- sectional view ofthe flexible curtain illusfrated in Fig. 1 taken along the lines 4A-4A. Fig. 4B is a cross-sectional view ofthe flexible curtain illusfrated in Fig. 1 taken along the lines 4B-4B. Support frame 407 is interconnected to the frame ofthe building opening. Fig. 4 illusfrates the environment ofthe invention. Fig. 4A illustrates window 401 along with interior wall 402 and an exterior sheathing 403 such as plywood. A space 404 between the window 401 and curtain 115 is illustrated. Fig. 4C is a full cross-sectional view of Fig. 4A illusfrating the application ofthe invention to protect a window opening. Referring to Fig. 4C, reference numeral 405 represents a full sized 38" window taken along the lines 4A-4A without frack 112 shown. Reference numeral 406 generally indicates wood framing. Still referring to Fig. 4C, windup reel 107 is indicated and the curtain is shown in both a minimum position indicated by reference numeral 408 (i.e., the curtain in its down, second position) and a maximum position as represented by reference numeral 409 (i.e., the curtain in its up, first position). Reference numeral 404 indicates the space between the curtain 115 and the window to be protected 401. The curtain may be a flexible three ply curtain or it may be corrugated. Some regulatory authorities have promulgated a standard such that the curtain may not deflect within 1" ofthe glass 401 under hurricane sfrength winds. In Fig. 4C, the wind pressure and/or debris is coming from the rightward side ofthe drawing figure and is headed leftwardly. In Fig. 4C, the curtain resides exteriorly ofthe window, door or other building opening. In Fig. 34, the wind, debris and pressure "P" is illusfrated as coming from the leftward side ofthe drawing figure and is headed rightwardly. In Fig. 34, a flexible three ply curtain 2805 is depicted. A single ply or double ply curtain may also be used. In Fig. 34, the curtain 2805 resides interiorly to the window, door or other building opening. In the embodiment of Fig. 34, the window 401 would be smashed by debris in a hurricane, but the building would still be protected. Reference numeral 3402 represents the exterior wall and reference numeral 3403 represents the interior wall in Fig. 34. Slot 2820 restrains the curtain 2805 at the bottom. Fig. 4D is a cross-sectional view similar to that of Fig. 4A illusfrating the wind-up reel 107 (sometimes referred to herein as the storage reel) in greater detail adapted for use in connection with the three-ply flexible curtain and the cog drive. Fig. 5 is a schematic view ofthe 72" curtain illusfrating a 1° runout of the leftside frack, tension rods, and interrupts. Reference numeral 500 generally indicates a schematic representation of a 1° runout for a 72" long window. The interrupts are actually at a 1° angle which matches the angle of mating surface 203 on the "J-shaped" portion ofthe frack. Fig. 11 illusfrates the top of a 72", 1° frack in cross section. The "J-shaped" portion ofthe track in Fig. 11 is indicated by reference numeral 1101. Referring again to Fig. 5, the dashed unnumbered lines are at 1° angle with respect to the side 220 of curtain 115. The outer edge 20 IB ofthe frack at the bottom is approximately 1.25" leftwardly ofthe point marked by reference numeral 201 in the preferred embodiment ofthe 72", 1° curtain. The intermediate support 202 at the bottom has a runout ofthe same magnitude as indicated by reference numeral 202B. All ofthe runouts, ofthe rods, the interrupts, and the tracks are the same. When all ofthe rods progress to their closed, second position as illustrated in Figures 1 and 5, the interrupts engage the mating surface 203 of the track and wedge into place. This secures the curtain in its closed position. Reference numeral 203B illustrates the runout ofthe mating surface at the bottom ofthe 1°, 72" long building opening. Reference numeral 501 illusfrates the runout ofthe outside ofthe frack. Reference numeral 502 illustrates runout ofthe tension rods. It will be noted that the tension rod 124 illusfrates a runout of approximately 1.25" from the side ofthe curtain 220. Reference numeral 503 illusfrates a runout ofthe interrupt engaging surfaces with the mating surface 203 of frack 111. Reference numeral 504 illusfrates the runout ofthe inside portion of track 111. Curtain 115 has no runout as illusfrated by reference numeral 505. Track 111, at a 1° angle, must have a relatively wide mouth, or opening, for use in protecting a 72" long building opening. Given that reference numeral 502 defines the runout ofthe rods and, indeed, the end of tension rod 124, it must fit within the track as it enters from its stored, open, first position. Fig. 5 illusfrates that point 502 will fit within the mouth of frack 111 as defined by its outer edge 201. Fig. 6 is a front view ofthe 72 inch curtain similar to that illusfrated in Fig. 1 except that the left side and right side tracks are parallel to each other and additionally the tension rods do not have any runout. Fig. 6 is one ofthe illustrations ofthe second (parallel) embodiment. Reference numeral 600 generally refers to the parallel embodiment. Left side frack 602 and right side track 603 are illustrated as being parallel to each other. Drive apertures 616 and 617 are driven by gears as was indicated in connection with the gears 119 and 120 of Fig. 1. The left side 620 ofthe curtain is parallel to the right side 630 ofthe curtain and the interrupt ofthe first rod 705 (Fig. 7) is in the same position relative to the frack 602 as is the last rod 627 (Fig. 6). Fig. 7 is an enlarged portion of Fig. 6. Fig. 7 illustrates first tension rod 701, second tension rod 702, and third tension rod 704. Interrupts 705, 707 and 710 include respective mating surfaces 706, 708, 709. Those mating surfaces are spaced apart from the conjugate mating surface 703 on the "J-shaped" portion 718 ofthe frack 602. Fig. 6 illustrates the curtain in its second, fully down position. In this second embodiment the interrupts do not wedge and engage with the mating surface 703 on the guide 602 unless pressure due to wind or debris is applied to the curtain. Rather, at rest, there is a distance of approximately 1/8" in the preferred embodiment between the mating surface 703 and the mating surfaces 706, 708, 709, etc. on the interrupts ofthe tension rods. Therefore, for engagement to occur between the mating surfaces on the interrupts and the mating surface on the J-shaped channel, the flexible corrugated curtain must be deflected and the rods must bow inwardly to move the mating surfaces (703, 706, 708, 709) into contact with each other. The interrupts for the parallel arrangement are approximately 0.50 inches in length and the end portions are spaced an additional .150 inches away from the mating interrupt surfaces. Reference numeral 711 indicates an end of a tension rod. Reference numerals 712 and 713 indicate the beginnings ofthe interrupts 705 and 707 in tension rods 701 and 702. The tension rods extend about .250 inches leftwardly and rightwardly ofthe corrugated curtain before the interrupts begin. The parallel arrangement is driven similarly to the wedging arrangement illusfrated in the previous drawing figures and Fig. 7 illusfrates teeth 719 on the gear driving the corrugated curtain. The preferred material ofthe corrugated curtain is polycarbonate and the preferred material ofthe tension rod is aluminum. As the cross-sectional areas ofthe tension rods increase, so does the shear sfrength ofthe rods. The "J-shaped" portion ofthe track is at an angle of approximately thirty degrees and the gap between the mating edge 703 ofthe J-shaped portion 718 and the support 702 is approximately 0.07 inches. Fig. 8 is a schematic representation ofthe flexible curtain, track and tension rods ofthe embodiment of Fig. 6. Reference numeral 800 generally indicates the parallel arrangement. Referring to Fig. 8, reference numeral 801 illustrates no runout ofthe frack 602, reference numeral 802 indicates no runout ofthe ends ofthe tension rods, reference numeral 803 indicates no runout ofthe mating surface of frack 602, and reference numeral 804 indicates no runout ofthe curtain. All embodiments employ a curtain having a zero runout. It should be noted in connection with the parallel embodiment that the interrupts are pressed (formed) such that they are parallel to the curtain and/or peφendicular to the longitudinal axes ofthe tension rods. Fig. 9 is a front view of a 38" curtain illustrating a 1/2° runout ofthe tension rods. Reference numeral 900 indicates the curtain generally, slits 926 add flexibility to the curtain and drive apertures 916 and 917 are indicated as well. Fig. 9 A is similar to that of Fig. 1 illusfrating a l A° runout ofthe tracks, interrupts, and tension rods. Reference numeral 900A illusfrates the 38" long curtain having a l A ° runout in its fully extended down or second position. Left side track 911 runs out as indicated by reference numeral 913 which is the lower portion ofthe left side track. Similarly, reference numeral 914 indicates a small, X A° runout ofthe right side track 912. The last tension rod 924 illustrates a relatively small space between the curtain 915 and the interrupts on that last tension rod 924. A counterbalanced wind-up reel 907 is employed as illustrated in Fig. 9A. Bottom bar 918 is illusfrated in Fig. 9A. Fig. 9B illusfrates an enlarged portion of Fig. 9. A relatively small runout between the near side interrupts 931 and 932 (first and fifth rods ofthe curtain) is indicated. In other words, interrupt 932 ofthe fifth rod down is not much leftwardly relative to the interrupt 931 ofthe first rod. Fig. 9C is a perspective view of a portion of a curtain having a l A° runout further illusfrating the corrugated flexible curtain 915 and interrupts 906, 908 and 909 mating with the corresponding mating surface 903 at points 903 A, 903B and 903C on the "J-shaped" portion 904 of track 911 when the curtain is in its fully down or second position. In this position movement of the flexible curtain toward the window is restrained and the curtain has been wedged into place. Fig. 9C illusfrates the "J-shaped" portion 904 angled back (with respect to the side ofthe curtain). Mating surface 903 is at the same angle as the mating surfaces on interrupts 906, 908 and 909. Reference numerals 903 A, 903B and 903 C signify a flush contact between the "J- shaped" portion 904 ofthe frack 911 and the respective interrupts. Fig. 9C also illustrates the outside edge 901 ofthe frack and this figure does a particularly good job in representing the corrugated curtain 915. Corrugations 936 can be viewed in apertures 916 are indicated as are face slits 926. Reference numeral 935 illusfrates the rectangular in cross-section rod extending through the curtain 915. It will be noticed that where the rods extend through the curtain that there is no slit at a corresponding point in the face. The rods are sealed within the curtain so that contaminants such as sea salt cannot reach them enabling a low maintenance curtain. Fig. 10 is a schematic representation similar to that of Fig. 5 only it will be noticed that the angle is l A° illusfrated over a 38" length as compared to 1° angle illustrated over a 72" length in Fig. 1. It will be apparent when viewing Fig. 10 that a smaller mouth or area is needed to receive the bottom rod of a l A°, 38" curtain system because the runout is much less. Reference numeral 1000 generally indicates this schematic representation. The side of curtain 1013 does not have any runout. Curtain 1015 includes apertures 1016 and the bottom bar is denoted by reference numeral 1018. Track 1011 has an outer edge 1012 whose runout is indicated with reference numeral 1001. Similarly the first tension rod has an end 1020 whose runout is indicated with reference numeral 1002. The first mating interrupt ofthe first rod is indicated by reference numeral 1007 and its runout is indicated by reference numeral 1003. Finally, the inner portion ofthe guide also has a runout as indicated by reference numeral 1004. Reference numeral 1009 illusfrates the surface ofthe "J-shaped" portion ofthe frack 1011 which mates with the interrupts. In this l A°, 38" embodiment, the interrupts are also at a l A° angle mating arrangement. The frack support 1008 performs the same function that the frack support performs in the first embodiment in that it supports and restrains the rods during tensioning. During tensioning, the rods will pivot slightly on mating surface 1009 and the end portions thereof, for example end portion 1020, will engage support 1008. The frack supports (i.e., 1008) are necessarily close to the mating surface (i.e., 1009) ofthe "J-shaped" portion ofthe frack in the embodiments employing an angled frack as well. Bending moments are thus minimized because the gap is preferably small, on the order of .007 inches. The distance between the mating surface 1009 and the frack support 1008 is important. If this distance is too large then the rods tend to shear as the bending moment caused by the structure ofthe curtain with the rods therethrough is too large. It has been found that a preferred distance between the frack support 1008 and the mating surface 1009 ofthe track is approximately 0.07 inches. This distance can, however, be changed as those skilled in the art will appreciate. Fig. 11 is a top view ofthe leftside frack like that of Fig. 1 illusfrating the top rod in its fully down position engaging the frack. Fig. 11 illusfrates a cross-sectional view ofthe top ofthe track which has 1° runout. The runout, however, is not illusfrated in this drawing. Reference numeral 1100 generally illusfrates the rod and the relative spacing arrangements for a 72" long opening having a 1° runout. Rod 1104 includes a relatively long interrupt 1105. "J-shaped" portion 1101 of frack 1103 is shown engaging the mating surface 1106 ofthe interrupt 1005 ofthe rod 1104. In viewing Fig. 1 it is obvious that there are many rods employed in the curtain and each of those rods will seat against the "J-shaped" portion 1101 ofthe track 1103. Fig. 11A is a front view ofthe leftside track 1103 and the top rod 1104 illusfrated in Fig. 11. Reference 1100A generally illusfrates this front view. Gap 1108 is the space between the J-shaped portion 1101 and the track support 1109 and is preferably small (.007 inches). Fig. 1 IB is a top view of a leftside frack like that of Fig. 9 A illusfrating the top rod in its fully down position engaging the track. Fig. 1 IB illustrates a cross-sectional view ofthe top ofthe frack which has a l A° runout. The runout, however, is not illusfrated in this drawing. Reference numeral 1100B generally denotes the view. It will be noticed that the track 1103B is somewhat smaller when compared to the frack necessary for a 72" opening having a 1° runout. Further, it will be noticed that the rod 1104B includes a smaller interrupt 1105B as compared to the 72", 1° runout. "J-shaped" portion 1101B engages the mating surface 1106B of interrupt 1105B. End portion 1107B ofthe frack is supported by support 1109B during tensioning as was discussed previously. Gap 1102B is illustrated between "J-shaped" portion 110 IB and track support 1109B. Fig. 1 IC is a front view ofthe leftside track and top rod illusfrated in Fig. 1 IB. Reference numeral 1100C generally denotes this view. Reference numeral 1200 generally denotes this view. Fig. 12 is a top view of a leftside frack like that of Fig. 1 illustrating the bottom rod in its fully up position entering the frack. Fig. 12 illustrates a cross-sectional view ofthe top ofthe frack which has a 1° runout. The runout, however, is not illustrated in this drawing. It will be noticed that the interrupt 1205 is relatively and necessarily large. Because this interrupt is relatively large a relatively large mouthed frack 1203 is necessary to in effect swallow or accept the tension rod 1204. The interrupt must straddle the gap 1202 between the "J-shaped" portion 1201 ofthe frack and the frack support 1209. This is caused by a long or large 72" opening having tracks at 1° divergence from vertical. Put another way, the tracks have a 2° divergence from frack to frack. The end 1206 of rod 1204 must have sufficient clearance inwardly from frack 1203 to enter it. Fig. 12A is a front view ofthe leftside track and the bottom rod illustrated in Fig. 12 and reference numeral 1200A generally denotes this view. Fig. 12B is a top view of a leftside frack like that of Fig. 9 A illusfrating the bottom rod 1204B in its fully up position entering the frack. Fig. 12B illusfrates a cross-sectional view ofthe top ofthe frack which has a l A° runout. The runout, however, is not indicated in this drawing. Reference numeral 1200B generally denotes this view. A smaller frack 1203B is acceptable because the runout over a 38" long opening having tracks that diverge l A° from vertical or 1° from each other does not require a lengthy interrupt 1205B. Additionally, it will be noticed too that there is a small clearance between the "J-shaped" portion 1201B ofthe frack 1203B and the interrupt 1205B. This is necessary so that the rods may progress downwardly without much friction. Clearance is indicated in all of Figs. 11 and 12. Sufficient clearance between end portion 1206B ofthe rod 1204B and the track 1203B is indicated. Gap 1202B is indicated between J-shaped position 120 IB and the support 1209B. Fig. 12C is a front view ofthe leftside frack and the top rod as illustrated in Fig. 12B and reference numeral 1200C generally denotes this view. In all of Figs. 11 and 12, the J-shaped portion is at an angle of 30° and the gap between the mating surface ofthe J-shaped portion and the support is 0.07 inches. This geometry provides good securement ofthe curtain under load. Returning to Fig. 5 the problem associated with a long opening such as the 72" opening employing a frack at 1° to vertical (2° angle divergent from track to frack) is that the width ofthe interrupt must increase so that it may straddle the "J-shaped" mating surface and still be within (short of) the outer edge ofthe track. Therefore, although this invention is useful over any practical angle of divergence from track to track, it is usually more economical to employ a l A° runout and wedge than a 1° runout and wedge for long openings. The wedge principle works over any practical angle, but it may be more economical for some combinations of angle and length than others. Fig. 13 is a cross-sectional view ofthe bottom bar 1300 sealingly engaging the bottom sill 1304 which is affixed to the frame 1306, 1307 ofthe structure. Fig. 13 illusfrates a curtain 1309 which is corrugated. Corrugated curtain 1309 is affixed to the bottom bar 1300 by means of a fastener 1310. Magnet 1302 is a part of bottom bar 1301 and is attracted to the sill or other structure. Sill 1304 includes seal 1308 which is restrained in sill 1304 by means of adhesive or epoxy. The wood frame traps sill portion 1305 to assist in holding the sill in place. Catch 1303 engages sill 1304 when curtain 1309 is sufficiently flexed by wind or debris. Fig. 13A is a cross-sectional view of a three-ply flexible curtain 1300 A. Two polymeric sheets or plies 1320, 1321 are pressed and fused into engagement with a woven ply 1322 which is affixed by fastener 1310 to bottom bar 1301. Fig. 13B is a cross-sectional view of a three-ply flexible curtain 1300A together with a vertically bowed bottom bar 1330 entrapped by adhesive/lamination ofthe flexible curtain. Fig. 13C illusfrates entrapment of bottom bar 1330 by stitching the plies together. The bowed bar 1330 is illustrated in Fig. 13D and functions to guide the curtain into a retaining slot 2820 as illusfrated in Figs. 28C and 28D. When wind pressure or pressure from debris is applied, the middle portion 2841 ofthe curtain may bow toward the window. The side portions, however, are guided by the tracks (2801, 2204) and the bottom portion 1340 ofthe curtain is vertically bowed and is guided into retaining slot 2820 first below the tracks and then in the middle. The bottom portion is restrained by the tracks against the pressure of the wind. This gets the curtain started at the sides ofthe retaining slot and the middle of the curtain follows. Fig. 14 is a perspective view of a tension rod 1401 having an interrupt 1402 in an end portion 1404 and having an interrupt 1403 in an end portion 1405. The rod is generally represented by the reference numeral 1400. The tension rod is rectangular in cross-section and the cross-sectional shape has been found to be the strongest shape. Other shapes, however, may be used. Fig. 15 is an enlarged portion ofthe tension rod 1401 illusfrated in Fig. 14. Interrupt 1402 is shown having curved radii 1501, 1502 and 1503. Reference numeral 1500 generally denotes the end portion ofthe rod. Flat portion 1504 shown inwardly from radius 1502 engages the mating surface of the "J-shaped" portion ofthe track. Fig. 16 is another enlarged view of a portion of a tension rod. Reference numeral 1600 generally indicates the end portion ofthe tension rod with end 1602 and radius 1601. Mating surface 1601 is a good representation of an angled surface with respect to the longitudinal axis ofthe tension rod. It is this mating surface 1601 which engages a similarly angled mating surface on the "J-shaped" portion ofthe tracks. In other words, surface 1601 is at an angle with respect to the longitudinal axis ofthe rod. Similarly Fig. 17 is a view ofthe end portion of a tension rod illusfrating a circular in cross-section tension rod. Reference numeral 1700 generally represents this embodiment with end portion 1702 having an interrupt formed therein with mating surface 1701 being angled to match the "J-shaped" portion ofthe tracks. When the embodiment of Fig. 6, to wit, a parallel arrangement is illusfrated, the mating surfaces 1601 and 1701 will necessarily be peφendicular to the longitudinal axes ofthe tension rods. The tension rods are preferred to be rectangular in cross-section so as to maximize the area filled in the corrugated material which is rectangular in cross-section. The rectangular in cross-section rod has been found to be the strongest because it occupies the largest cross-sectional area. Fig. 18 is a plan view of a tension rod illusfrating the interrupts 1402 and 1403. Reference numeral 1800 is a general designation for this rod. Dashed lines 1801, 1802, 1803 and 1804 correspond to angled frack. Fig. 19 is a side view of a tension rod of Fig. 18 illustrating the interrupts therein. Reference numeral 1900 is a general designation for this view ofthe rod. Fig. 20 is a perspective view ofthe track which has been referred to in this figure by reference numeral 2000. J-shaped portion 2001 is well shown in this illustration. Fig. 21 illusfrates a plan view of one ofthe tracks 2000 with bolt holes or apertures 2101 for fixing to a casing or frame. Reference numeral 2100 generally denotes this drawing figure. Fig. 22 is a cross-sectional view of a three-ply flexible curtain 2200 taken along the lines 22-22 of Fig. 28. Figs. 22-29 illusfrates the third embodiment ofthe invention. A first polymeric sheet 2201, a second polymeric sheet 2202, and a third woven sheet 2203 are heated and pressed together forming the construction of a flexible curtain. Track 2204, preferably metal, is illusfrated in Fig. 22. The edges ofthe flexible curtain 2200 are folded upon themselves and are maintained in the folded position by stitching 2205. Alternatively, the folds may be glued to the curtain. The stitching is preferably placed such that 1/3 ofthe folded flap will be loose and 2/3 ofthe folded flap will be secured to the curtain. Drive apertures 2206 are shown and reference numeral 2207 indicates the loose flap. Reference numeral 2208 indicates the folded portion ofthe curtain. Fig. 22 A is identical to Fig. 22 only eyelet 2209 in aperture 2206 is illusfrated. Eyelets 2209 add sfrength for driving the curtain between its first, open and second, closed positions. It may be noticed that the cross-hatching used for the plies 2201 and 2202 appear to cause an optical illusion such that the plies do not appear parallel but, in fact, they are parallel. Figs. 22B and 22C are identical to Figs. 22 and 22 A, respectively, but Figs. 22B and 22C do not include the cross-hatching. Figs. 22B and 22C do not portray any optical illusions. Fig. 23 is a cross-sectional view taken along the lines 23-23 of Fig. 28. Fig. 23 A is identical to Fig. 23 without cross-hatching ofthe polymeric plies illustrated. Figs. 23 and 23 A illustrate the curtain without any pressure applied. Figs. 23B and 23 C correspond to Figs. 23 and 23 A, respectively, only they are illustrated with pressure applied. Figs. 23B and 23 C are cross-sectional views ofthe three-ply curtain and tracks with the curtain under the influence of a force, for example, a high velocity wind indicated by the letter "P." The force ofthe wind causes the curtain to attempt to exfract itself from the tracks 2204 and 2801. The folded edge which have loose flaps are deformed and seal the interior ofthe tracks 2204 and 2801. There are at least four sealed points 2302, 2303 on the right side and 2304, 2305 on the left side when viewing Figs. 23B and 23C. Gaps 2306 and 2307 are created between the flaps 2207 and 2209 the three-ply flexible curtain when the curtain is under pressure "P." Gap 2308 between frack 2204 and the folded edge is created as the curtain attempts to exit the track. Similarly, gap 2309 between frack 2801 and the other folded edge is created as the curtain attempts to exit the frack. As force is applied, flaps 2207 and 2209 are no longer loose and act as shock absorbers which take up energy imparted to the curtain by the wind. The elastic properties ofthe flexible curtain absorb the energy ofthe wind. Hook portions 2210 and 2811 of tracks 2204 and 2801 are spaced from the curtain at rest such that the aforementioned seals will be made when the curtain is subjected to pressure. Fig. 24 is a cross-sectional view of a three-ply curtain together with a semi-rigid polymeric strip 2401 affixed to one edge thereof. The polymeric rigid strip 2401 includes a flap 2402 which is not securely fastened to the three-ply curtain 2400. Stitching 2405 or other means may be used to affix the strip to the curtain 2500. Fig. 25 is a cross-sectional view of a three-ply curtain similar to the view of Fig. 23 with the curtain under the influence of a force, "P," for example a high velocity wind. A seal is made at points referred to by reference numerals 2503 and 2507. Gap 2504 exists between the rigid strip 2402 and the main three-ply curtain. Fig. 26 is a cross-sectional view of a three-ply curtain having a folded edge and illusfrating two polymeric plies 2201 and 2202 and a woven sheet 2203 secured together with adhesive 2601. Reference numeral 2602 indicates a 1/3 flap length as the preferred free distance ofthe flap. Similarly, reference numeral 2603 illustrates that 2/3 ofthe flap is secured by stitching 2205. Those skilled in the art will readily recognize that different lengths may be chosen for securement with attendant different results. In the preferred embodiment the frack has an approximate inner length of one inch meaning that 1/3 of an inch would be the free distance for the flap and 2/3 of an inch would be the secured distance for the flap. These distances represent the preferred embodiment and in no way limit the invention. Fig. 26A illustrates adhesive 2609 affixing a portion ofthe semirigid strips 2401 to the main three-ply curtain. Alternatively, a strip ofthe three-ply curtain may be used in place ofthe semirigid strip. Fig. 26B is a cross-sectional view of an embodiment employing two plies of polymeric material 2615, 2616 secured together with a fiber reinforcement 2617. This material is high-tear vinyl polyester and is commercially available from BONDCOAT MANUFACTURING COMPANY. A loose flap 2620 has been slit such that it engages truck 2204 at lip 2210 when the curtain is under the influence of pressure. The slit may be used in either the horizontal or the divergent angle embodiments. Fig. 27 is a rear view ofthe three-ply flexible curtain 2700 illusfrating a semi-rigid strip applied to both edges ofthe curtain. Semi-rigid strip 2702 is applied to the left side ofthe curtain and semi-rigid strip 2701 is applied to the right side ofthe right edge ofthe curtain. Apertures 2703 are placed in a repeating fashion along the left and right side edges ofthe curtain for interengagement with conical cogs to raise and lower the curtain. Fig. 28 is a front view of a three-ply curtain 2805 driven by a cog/pin drive 2802 (sometimes referred to herein as the drive roller 2802) having cogs/pins 2803. Leftside frack 2801 is illusfrated in Fig. 28 as is rightside track 2204. These tracks are secured to the building structure as indicated in Fig. 4. Wind-up reel 2804 sometimes referred to herein as a storage reel is illustrated and it is also counterbalanced. See, Fig. 28B. Fig. 28 illustrates the curtain in its second, down position. Fig. 28A is a cross-sectional view taken along the lines 28A-28A of Fig. 28 illustrating the drive roller 2802. The drive roller 2802 is driven by a motor or by a hand operated pulley. See, Fig. 1 illustrating an arrangement for accomplishing operation ofthe drive roller 2802. The drive roller 2802 and the storage reel are supported as illustrated in Fig. 1. The drive roller 2802 supports the curtain which is under constant tension between the cogs/pins 2803 and the storage reel 2804. In practice, the three-ply curtain is less than 1/16 of an inch thick and, where folded, less than 1/8 of an inch thick. It is important to keep the flexible curtain taut between the storage reel 2804 and the drive roller 2802 so as to ensure an even accumulation ofthe curtain on the storage roller. By even, it is meant a smooth continuous winding without folds or creases. Fig. 28B is a cross-sectional view taken along the lines 28B-28B of Fig. 28 illusfrating counterbalanced springs 2820', 2821 which tension the curtain between the drive cogs 2803 and the storage reel 2804. The springs are grounded by pegs 2850 which are coupled to the building 2840. Spring holders 2822, 2833 secure the spring to the storage reel 2804. Fig. 28C is a view similar to Fig. 28 further illustrating a bowed bottom bar 1340 approaching a retaining slot 2820 as illustrated in Fig. 28D as previously described above. Tracks 2801 and 2204 keep the edges ofthe curtain aligned with the retaining slot. The edges 1341, 1342 ofthe bottom portion 1340 of the curtain enter the retaining slot 2820 first followed by the middle portion. Fig. 28E is a front view of flexible curtain 2805 and window 2870 in a building illusfrating the curtain in a first, open position. Bottom bar 1340 is shown in phantom behind siding 2860. Reference numeral 2880 indicates travel ofthe curtain upwardly and downwardly. Fig. 28 F is a front view of a flexible curtain 2805 illustrated in the second, closed position. Window 2870, side tracks 2801 and 2204, and retaining slots 2820 are illusfrated in Fig. 28F in phantom. The side tracks and retaining slots are affixed to the frame ofthe building in a manner understood by those skilled in the art. Alternatively, the window 2870 and curtain may be preinstalled as illustrated in Figs. 4B and 4D, for example. Frame 407 in Fig. 4B represents an embodiment which may be used to preinstall the window and curtain. Fig. 29 is a side view of Fig. 28 and reference numeral 2900 generally indicates the assembly. Track 2204 is also shown in Fig. 29. Fig. 30 is a perspective view ofthe chain drive (drive adaptor rack) and gear drive. In this embodiment the tension rods 3006 pass through the flexible curtain 3007 and are tensioned and rolled up upon counterbalanced wind-up reel 3009. Adaptor rack 3001 includes notched holes 3002 that are vertically spaced between slots 3003 with rods 3006 at a spacing equal to the circular pitch ofthe drive gear 3005 as the curtain is moved from the opened, first position to the closed, second position. The drive system of Fig. 30 is preferably used with the parallel embodiment but with certain modifications it may be used with the divergent track. Fig. 31 is a perspective view of an adaptor rack 3104 illustrating tensioning rods 3101 having a 90° bend 3102 at the edges thereof. This embodiment ofthe drive system may be used with the divergently angled tracks or it may be used with the parallel tracks. Rods 3101 pass through corrugated curtain 3106. Track 3105 is the same frack described previously. Fig. 32 is a perspective view of an adaptor drive illusfrating engagement of tensioning rods 3203 with the adaptor drive 3201 . Fig. 33 is a perspective view of a gear drive such as the one illusfrated in Fig. 1 and is generally represented by reference numeral 3300. Gear 3303 includes teeth 3301 which drive the flexible curtain 3302. Fig. 33 illustrates the curtain in the down, second position. Fig. 35 is a perspective view 3500 of another embodiment ofthe track 3520 in which the track 3520 includes two pieces, a first piece 3501 and a second piece 3514. The first piece 3501 and the second piece 3514 interfit. Protrusions 3506 and 3507 on the second piece 3514 interengage corresponding grooves (unnumbered) in the first piece 3501. First 3501 and second 3514 pieces may also be mechanically fastened together by any one of several ways. First they may be spot welded 3512. Spot welds 3512 are created by fusing the metal ofthe first piece 3501 and the second piece 3514 together externally. A gap 3505 exists between laterally extending portions of the two pieces ofthe frack. Where fused through welding the gap 3505 does not exist. Alternatively and/or additionally the first and second pieces may be screwed 3513, riveted 3515, or held together with adhesive 3518. If the track is made of plastic it can be ulfrasonically welded together. First piece 3501 includes an axially extending cavity 3502 and a curtain engaging portion 3516. Sometimes herein curtain engaging portion 3516 may be referred to herein as a flange. Smooth contours 3509 exist on the engaging portion 3516 of the first piece. These smooth contours 3509 help prevent the tearing ofthe curtain 3601 as viewed in Figs. 36 and 37. Likewise, second piece 3514 includes a curtain engaging portion 3517 which has smooth contours 3510 thereon. Also, referring to Fig. 37A contour 3510 assists in preventing curtain 3601 from being extracted from the frack under loaded conditions. Additionally, the contours ofthe track seal against a coating on the flexible curtain. The flexible curtain is a polymeric material and it may be reinforced with polyester. Further, the flexible curtain may be coated with a silicone or polyvinyl chloride or the like. The coated surface is a smooth surface which engages the contours ofthe frack under loaded conditions to provide a seal. Sometimes herein curtain engaging portion 3517 may be referred to herein as a flange. Axially extending cavity 3511 is formed by the joinder of first piece 3501 and second piece 3514. Axially extending groove 3508 is also formed by the joinder ofthe first and second pieces of frack 3520. Groove 3508 may be tack welded to additionally secure the pieces together. Second piece 3514 ofthe frack includes an axially extending strut 3519 which resides within reciprocally shaped axially extending groove in first piece 3501. Small gaps 3503 and 3504 exist between axially extending strut 3519 and the first piece which allows for some movement between the first and second piece. Flexure ofthe first and second pieces relative to each other absorbs energy during storm conditions. Fig. 36 is a cross-sectional view 3600 ofthe frack illustrated in Fig. 35 together with the flexible curtain 3601 having semi-rigid strips 3605, 3607 affixed thereto. Semi-rigid strips 3605 and 3607 are affixed to the curtain by stitching, ultrasonic welding, gluing or by other methods. Right 3602 and left 3603 tracks are affixed adjacent a building opening. Fig. 36A is an enlarged portion of Fig. 36 illustrating a gap between the semi-rigid strip 3607 and the engaging portion 3516 ofthe track. Fig. 36A also illustrates the contours 3509, 3510 ofthe track. Fig. 37 is a cross-sectional view 3700 ofthe tracks of Fig. 35 together with the curtain under the influence of a positively directed pressure. Fig. 37A is an enlarged portion of Fig. 37 illusfrating the curtain 3601 and the semi-rigid strip 3607 engaging the engaging portion 3516 ofthe track. Figs. 37 and 37A illustrate the curtain under the influence of positive pressure. Contour 3509 is smooth and curved 3702 so that the curtain 3601 is not torn or scraped by the track under the influence ofthe wind. Referring to Fig. 37 A, a seal is made between curtain 3601 and contour 3702 on flange 3516. Reference numeral 3701 indicates the engagement of semi-rigid strip 3607 engaging flange 3516. Fig. 38 is a cross-sectional view 3800 ofthe curtain 3601 and the tracks under the influence of a negatively directed pressure on the curtain. Fig. 38A is a cross-sectional view of an enlarged portion of Fig. 38 illusfrating the engaging portion 3517 ofthe frack and the curtain 3601 engaging the smooth contours 3510 of the frack. Referring to Fig. 38 A, reference numeral 3802 illusfrates the semi-rigid strip 3607 engaging the flange 3516 of the track at point 3802. Fig. 38A illusfrates the curtain 3601 engaging the smooth contour 3510 of the track. Contour 3510 is rounded so that the abrasion ofthe curtain will be minimized. Curtain 3601 seals against flange 3517 at the point indicated by reference numeral 3801. Fig. 39 is a cross-sectional view 3900 of a two-piece frack construction wherein one piece interfits with the other piece. Fig. 39 illustrates the housing piece 3902 together with the interfitting piece 3901. Housing piece 3902 includes an axially extending key-shaped channel 3910. Interfitting piece 3901 includes an axially extending key 3909 which mates with the key-shaped portion 3910 of housing piece 3902. The interfit between the housing piece 3902 and the interfitting piece 3901 is tight and leaves a substantially small space therebetween. Interfitting piece 3901 includes a flange 3905. Smooth contours 3906 and 3907 reside on flange 3905 and function as previously described above. Similarly housing piece 3902 includes a flange 3908 having smooth contours 3903 and 3904 which function as previously described hereinabove. Housing piece 3902 and interfitting piece 3901 form an axially extending cavity. The flanges 3905, 3908 are spaced apart forming an axially extending opening. Edges of curtain 3601 and the semi-rigid strips attached thereto reside within the axially extending cavity. Fig. 39A is a cross-sectional view ofthe housing piece 3902 ofthe two piece interfitting frack system 3900. Fig. 39A illusfrates the axially extending key-shaped channel 3910. Flange 3908 is illusfrated having smooth contours 3903 and 3904 thereon. Referring to Figs. 39, 39A, and 39B, the smooth contours 3903, 3904 and 3906 function as described hereinabove so as to protect the curtain 3601 from abrasion and tearing. Additionally, contours 3903, 3904 and 3906 engage curtain 3601 and seal therewith as described above. Fig. 39B is a cross-sectional view ofthe interfitting piece 3901 ofthe two piece frack system 3900. Fig. 39B further illustrates the axially extending key 3909 which interfits the axially extending key-shaped channel 3910 as viewed in Fig. 39A. Flange 3905 is illusfrated having smooth contours 3906 and 3907 in Fig. 39B. The function of flanges 3906 and 3907 is as stated previously. * Those skilled in the art will readily recognize that the frack system described herein and illustrated in Figs. 35-39B inclusive may be changed or modified without departing from the spirit and scope ofthe attached claims. For instance, the tracks may be oriented at divergent angles. It will be understood by those skilled in the art that several changes may be made to the instant invention without departing from the spirit and scope ofthe claims which follow hereinbelow.

Claims: WHAT IS CLAIMED IS: I . A frack for use in a windlocking apparatus comprising a housing piece; an interfitting piece; said housing piece includes a channel and said interfitting piece includes a key which slidingly mates with said channel. 2. A frack as claimed in claim 1 wherein said interfitting piece includes a first flange and said housing piece includes a second flange and, said first and second flanges each have smooth contours thereon. 3. A track as claimed in claim 2 wherein said housing piece and said interfitting piece form an axially extending cavity. 4. A track as claimed in claim 3 wherein said first flange of said interfitting piece and said second flange of said housing piece are spaced apart forming an opening to said axially extending cavity. 5. A frack for use in a windlocking apparatus comprising a first piece and a second piece; said first piece includes at least one groove therein and said second piece includes at least one protrusion thereon; and, said protrusions of said second piece interfits said groove of said first piece locking said first and second piece together. 6. A frack for use in a windlocking apparatus as claimed in claim 5 wherein said first and second pieces include laterally extending portions and wherein said laterally extending portions are affixed together. 7. A frack for use as a windlocking apparatus as claimed in claim 6 wherein said first and second pieces are welded together. 8. A track for use as a windlocking apparatus as claimed in claim 6 wherein said first and second pieces are glued together. 9. A track for use as a windlocking apparatus as claimed in claim 6 wherein said first and second pieces are riveted together. 10. A frack for use as a windlocking apparatus as claimed in claim 6 wherein said first and second pieces are screwed together. I I . A frack for use in a windlocking apparatus as claimed in claim 5 wherein said first piece and said second piece form an axially extending cavity. 12. A frack for use in a windlocking apparatus as claimed in claim 5 wherein said first piece includes a first flange and said second piece includes a second flange; and, said first and second flanges each have smooth contours thereon. 13. A frack for use in a windlocking apparatus as claimed in claim 12 wherein said first flange of said first piece and said second flange of said second piece are spaced apart forming an opening to said axially extending cavity. 14. A windlocking apparatus for protecting a building opening comprising a first frack and a second track; a flexible curtain; said flexible curtain includes first and second edges each of which include a semi-rigid strip affixed thereto; each of said tracks include a housing piece and an interfitting piece; each said housing piece and said interfitting piece are interlocked together and forming an axially extending cavity; each said axially extending cavity includes an axially extending opening therein; and, said edges of said curtain and said semi-rigid strips reside within said cavities of said tracks. 15. A windlocking apparatus as claimed in claim 14 wherein each of said housing pieces and said interfitting pieces of said frack includes a flange thereon. 16. A windlocking apparatus as claimed in claim 15 wherein each of said flanges includes a smooth contour thereon. 17. A windlocking apparatus as claimed in claim 16 wherein said curtain seals against one of said contours on one of said flanges. 18. A windlocking apparatus for protecting a building opening comprising a first frack and a second track; a flexible curtain; said flexible curtain includes first and second edges each of which include a semi-rigid strip affixed thereto; each of said tracks include a first piece and a second piece; each of said first pieces includes at least one groove therein and each of said second pieces includes at least one protrusion thereon; and, each of said protrusion of said second pieces interfits each of said grooves of said first piece interlocking said first and said second pieces together and forming an axially extending cavity; each said axially extending cavity includes an axially extending opening therein; and, said edges of said curtain and said semi-rigid strips reside within said cavities of said tracks. 19. A windlocking apparatus as claimed in claim 18 wherein each of said first and second pieces of said frack includes a flange thereon. 20. A windlocking apparatus as claimed in claim 19 wherein each of said flanges includes a smooth contour thereon. 21. A windlocking apparatus as claimed in claim 20 wherein said curtain seals against one of said contours on one of said flanges.

Inventors: HUDOBA MARK S, MULLET WILLIS JAY, HUDOBA, MARK, S., MULLET, WILLIS, JAY
Applicants: WAYNE DALTON CORP, WAYNE-DALTON CORPORATION
Application year: 2001
Main classification: E05D
IPC codes: E06B9