Abstract:
A roof screen system comprises a number of triangular frames assembled from aluminum beams held together with pivotable clamps. Such clamps also bolt down onto roof footers with flashing boots that prevent roof leaks. A number of clips are attached to the upright triangular frames. Horizontal rails are then attached with the clips to the triangular frames, and screen panels are hung and attached to the rails. The pivotable clamps allow a slip-connection anywhere along the aluminum beams that can be locked down with ordinary wrenches. As such, the screen panels can be tilted back or forward to accommodate painted signs, electric signs, advertising, and even solar photovoltaic panels.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to roof screens used to hide mechanical equipment on building roof tops, and more particularly to roof screen systems that elevate a frame on weatherproof roof footers and allow sheet metal screening to be attached like fencing panels. 
     2. Description of Related Art 
     Roof screen systems are walls or facades built on commercial building rooftops to conceal roof mounted mechanical equipment. Also commonly referred to as “equipment screens” and “screen walls”. Conventional construction typically comprises wood and sheet metal framing and paneling components fastened together with nails or screws and supported by wood “sleepers” bolted through the roof. These conventional systems have a relative short service life and are notorious for being the source of roof leaks. 
     A roof screen system is described by the present inventor, Ryan W. Bruce, in U.S. Pat. No. 5,862,637, issued Jan. 26, 1999. Such system allows an architectural screen on top of a building to be secured to the roof. Air conditioning and heating units can then be put out of view from street level. The frames and footings used for these screens must be very strong to resist the tremendous lateral forces imposed by winds and gusts. Horizontal, vertical, and diagonal lengths of galvanized-steel angle-iron are welded into a triangle frame. Several parallel frames are all aligned on a rooftop and supported by round tubular feet with flat pads that lag-bolt to the roof. The screening bolts like a panel fence to the vertical sides of each frame, so the rest of the frame is inside behind the screen out of view. Special rain and weather flashings are slipped over the footings before the frames are attached. Such flashing is sealed to the footing and roof to prevent leaks that could develop due to the lag-bolts. 
     A similar roof screen system is marketed under the VIEWGUARD trademark by Royal Roofing Company, Inc. (San Jose, Calif.). This experience has resulted in seeing a number of ways that the prior art systems can be improved. For example, the galvanized steel material and the requirement for welding during assembly have been eliminated. Pitched roofs complicated the installation by requiring special cutting and welding. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide improved methods and materials for roof screens. 
     Briefly, a roof screen system embodiment of the present invention comprises a number of triangular frames assembled from aluminum beams held together with pivotable clamps. Such clamps also bolt down onto roof footers with flashing boots that prevent roof leaks. A plurality of parallel horizontal rails are attached to the triangular frames with clips, then bolted to the backs of screen panels. The pivotable clamps allow a slip-connection anywhere along the aluminum beams that can be locked down with ordinary wrenches. As such, the screen panels can be tilted back or forward to accommodate painted signs, electric signs, advertising, and even solar photovoltaic panels. 
     An advantage of the present invention is that a roof screen system is provided that is lightweight, weather-resistant, maintenance-free, and water-tight. 
     The above and still further objects, features, and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, especially when taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an end view of a single section of a roof screen system embodiment of the present invention shown mounted to a flat roof top; 
     FIG. 2 is a perspective diagram of a pivotable beam clamp or “knuckle” assembly embodiment of the present invention shown connecting one end of one beam to a longitudinal section of a length of adjoining beam; 
     FIG. 3 is a perspective view of a roofing footer embodiment of the present invention as used in FIG. 1; 
     FIG. 4 is a perspective view of a foot flashing boot or roof-jack that slips over the footer of FIG. 3, to seal out weather and prevent roof leaks; 
     FIG. 5 is an exploded assembly view of how a rail clamp, rail, and vertical front beam of the frame of FIG. 1 can all be joined and locked together in embodiments of the present invention; and 
     FIG. 6 is an end view of a rail clip being forced to lock inside a back side box channel of a rail with an open slot, a spreading bolt is shown forcing the wings of the rail clip apart. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 illustrates a roof screen system embodiment of the present invention, referred to herein by the reference numeral  100 . Embodiments of the present invention use rigid aluminum framing members assembled with die-cast aluminum knuckles to create a bolt-together system that eliminates any need for welding. For example, aluminum framing members of 6063-T6 extruded aluminum outside diameters of 2.45″ is useful. 
     The roof screen system  100  includes a screen panel  102  (shown on edge) mounted to a vertical framing member  104 , a horizontal framing member  106 , and a diagonal brace framing member  108 . A pair of roof footers  110  and  112  hold the system  100  aloft a few inches above a building&#39;s roof. 
     A knuckle  114  connects the diagonal brace framing member  108  to the horizontal framing member  106 . A similar knuckle  116  connects the horizontal framing member  106  to the top of the footing  112 . Another knuckle  118  connects the horizontal framing member  106  to the vertical framing member  104 . A knuckle  120  connects the horizontal framing member  106  to the top of the footing  110 . A knuckle  124  completes the frame by connecting the vertical framing member  104  to the diagonal brace framing member  108 . A bottom rail-clamp  126  and a top rail-clamp  128  attach the screen panel  102  to the vertical framing member  104 . In some installations, it is preferable to use screen pails that have more than just two horizontal rails, and this permits more than just two rail-clamps to be used to secure the screen to each vertical framing member  104 . 
     In some implementations of the present invention, it may be desirable to paint the screen panels  102  with advertising or other signs. Electrically lighted signs may also be bolted to the screen panels  102 . In some installations, the system  100  could also act as a rooftop or ground-level safety fence. The appropriate local building codes will direct how such safety fence should be configured to pass inspection. 
     During operation, strong wind forces will blow laterally against the screen panel. Frontal winds (that come from the left in FIG. 1) will put the diagonal brace framing member in compression. Back winds (that come from the right in FIG. 1) will put the diagonal brace framing member in tension. The knuckles  114 ,  116 ,  118 ,  120 , and  124 , all allow bolt-on assembly and yet will steadfastly lock the framing member  104 ,  106 , and  108  into a rigid triangular frame without requiring welding. Each knuckle allows the connection of one end of a framing member to anywhere along the length of another framing member. This permits the panel screen  102  to be vertically oriented even though the roof to which the footers are attached may be pitched. 
     Alternatively, the adjustability afforded by being able to slip the knuckles along the lengths of framing member can allow the framing member  104  to be locked in at some non-perpendicular angle. This could be useful where the system  100  is used to mount solar photovoltaic panels instead of panel screens  102 . The angle of the solar photovoltaic panels presented to the sun could easily be adjusted as the seasons change. 
     FIG. 2 illustrates a knuckle  200 , and is similar to knuckles  114 ,  116 ,  118 ,  120 , and  124  (FIG.  1 ). A single knuckle type can preferably be used in all five positions in FIG.  1 . The knuckle  200  is preferably of all-aluminum construction and can be die-cast and machined. Alternatively, such knuckle  200  can be made of plastic, steel, stainless or other material that is compatible with long-term exposure to the sun and weather. A cap  202  fits over one end of a beam  204 . A hinge pin  206  connects the cap  202  to a yoke  208  and clamp  210 . A second beam  212  can accommodate the yoke  208  and clamp  210  anywhere along its longitudinal length. A bolt  214  is used to tighten the clamp  210  on the beam  212  and lock it in place. A bolt is passed through the cap  202  and into beam  204 . As this bolt is tightened, it grips the inside of the beam. 
     The hinge pin  206  is such that beams  204  and  212  are free to pivot. Assembling three such beams and knuckles in a triangular frame will cause the whole assembly to lock into shape even though all the hinge pins are free to pivot. A triangle of just about any geometry can be formed by cutting the beams and sliding the knuckles to new positions. Such operations would be relatively easy for a worker to accomplish on a rooftop. 
     FIG. 3 represents a mild steel, hot dipped galvanized footer  300 . Each triangular frame (FIG. 1) typically requires two footers, e.g.,  110  and  112 . A number of bolt holes  304  are provided to secure the footer  300  to a roof or other surface. A stem  306  is premanufactured-welded to the base  308  with two gussets. 
     FIG. 4 illustrates a footer flashing boot  400  that is intended to slip over the footer  300 . The flashing boot  400  is hollow with a bottom cone section that joins a top section. The top has a bolt hole in the center that allows a knuckle cap to be bolted on. The footer  300  is bolted first to the roof, then the flashing boot  400  is slipped over. A flat rubber washer is preferably used under such bolt and under such knuckle cap to seal out weather from the interior of flashing boot  400 . The flashing can be constructed with a stem section  402  of neoprene rubber and a base section  404  of 0.020″ aluminum sheet. The flashing boot  400  is typically sealed to a roof by generally accepted roofing methods and consistent with the specific roof system. 
     FIG. 5 illustrates a spring clip  500  that can be used to secure the screen panels  102  (FIG. 1) to the vertical framing member  104 . The spring clip is made of stamped sheet metal in a V-shape with a flattened bottom. An upper wing  502  and a lower wing  504  are each provided with a beam hole  506  and  508 , respectively. Such holes are sized to allow a beam  510  to slip through when the wings  502  and  504  are squeezed together, and to lock when released. A pair of upper and lower dog-ears  512  and  514  are shaped so they will snap and lock inside an upper and lower channels  516  and  518  in a rail piece  520 . The spring clip is inserted into the open channel of the rail piece  520  by temporarily squeezing wings  502  and  504  together. Signs, solar panels, or screen panels can be attached directly to the rail pieces  520 , e.g., like rail-clamps  126  and  128  (FIG. 1) are to screen panel  102 . 
     FIG. 6 illustrates a rail clip  600  that can be used to secure the screen panels  102  (FIG. 1) to the vertical framing member  104 . The rail clip  600  is made of stamped sheet metal in a V-shape with a flattened bottom. An upper wing  602  and a lower wing  604  are each provided with a beam hole  606  and  608 , respectively. Such holes  606  and  608  are sized to allow beams, such as beams  204  and  212  (FIG.  2 ), and framing member  104  (FIG.  1 ), to just slip through. A pair of upper and lower dog-ears  612  and  614  are shaped so they can lock tightly inside an upper and lower channels  616  and  618  in a rail piece  620 . A bolt  622  is screwed in to force the dog-ears  612  and  614  to expand and lock the clip  600  inside channels  616  and  618 . 
     A typical installation proceeds as follows: The roof is marked with a crayon or spray paint where the corners of the roof screen will fall for the desired layout. Each corner must fall on a structural member. One footer is installed at each corner mark. Nylon strings are pulled between each corner footer to create a straight line for other intermediate footers. Such footers are installed at eight-foot intervals (maximum) along string lines. Each footer is positioned with the long side of the base perpendicular to the face of the roof screen. In other words, the footer should be positioned so that the wind load is against the short side of the footer base to allow an integral gusset to transmit the loads. It is crucial that any lag bolts used to attach the footers screw directly into the buildings structural members (studs or purlins) and be tightened securely. A secondary row of footers is similarly installed four to eight feet back from the primary row. Flashing boots are used on all footers with methods consistent with the type of roofing being used. 
     One frame is assembled at each corner by installing rubber gaskets onto the tops of the two footers for the corner frame. Caps are then installed over the footers and flashings. Metal backed rubber washers are placed on each cap bolt and the bolts with the washers are inserted through the caps into footers, but not yet tightened. A pivot bar, yoke and set screws are mounted onto each cap. A piece of the framing beam can be used as an alignment tool for the yokes. After the alignment tool is removed, the cap bolts can be tightened. A horizontal framing beam is assembled into the two yokes using the clamps and screws, but only loosely. Each such beam should extend four to six inches beyond each footer. The cap is installed over the end of the beam and the cap bolt threaded into the integral hole in the framing member, and now it can be fully tightened. The pivot bar and yoke are installed. The vertical framing beam is installed using the clamp and screws and is fully tighten. The beam is extended at least twelve inches higher than the desired roof screen height. A level is used to plumb the vertical member. The two clamps can then be tightened on the horizontal member to hold it all in place. A diagonal framing beam is measured and cut, and then installed using the same fittings as before. 
     The framing is then completed. A laser level, or transit, can be used to determine the top and bottom of the finished wall. The vertical members are marked at these points. A pair of nylon strings are pulled from corner to corner using the elevation marks to give a level reference point at the top and the bottom of the wall. For long runs, e.g., over sixty feet, it may be necessary to erect addition frames to prevent the string from sagging. Using the strings as reference points, the remaining frames are measured and cut. These are then assembled as before. 
     The panels and box-channel type rail are installed last. A laser level is used to shoot a line at the desired elevation for the top horizontal box-channel. At each frame, a number of clips corresponding to the number of rows of box-channel are installed starting with the clip at the top row. This clip is measured down from for subsequent clips. To install the rail clips, the clip is squeezed to slip around the beam. After installing the channel, the spreading bolt is used to secure it in place. The box-channel rows are installed by hooking the top edges to a clip, then pushing the bottom edge onto the clip, thus snapping them all into place. Splice plates are used to join box-channel sections end-to-end as necessary. The screen panels and any appropriate trim are then installed using the box-channels as attachment points. 
     In general, an embodiment of the present invention comprises frame assemblies spaced at a maximum of eight feet apart comprised of extruded aluminum framing member in conjunction with die-cast aluminum knuckle joint assemblies to form a triangular embodiment consisting of a vertical member, horizontal base member and a diagonal brace member. The vertical member varies in height to accommodate the desired wall height. The horizontal member can vary from four feet to eight feet depending on the roof structure. Each frame is supported by two mounting units called “footers”. A weatherproofing assembly or “flashing boot” is installed over the footer and sealed into the roofing system. The pivoting action of the knuckle assembly along with the rotating action of the beam at the connection to the knuckle assembly allows for unlimited adjustments for straightening and leveling the wall across an uneven roof surface. Horizontal spanning members referred to as box-channels are mounted across the frame assemblies to facilitate the metal panel attachments. The box-channels are mounted to “clips” that are clamped to the vertical members at the appropriate height. 
     The footer support is a premanufactured welded steel part consisting of a base plate, a mast and two gussets. The base plate includes mounting holes for attachment to the structure. Lag bolts are used for attachment to wood framed structures. Expansion bolts are used for structural concrete decks. The mast includes a threaded hole in the top to accept the anchoring bolt for the “cap” portion of the knuckle assembly. 
     The flashing boot comprises a watertight assembly that nests over the footer. It has a flange that extends out onto the roof surface and is incorporated into the roofing system. The top of the flashing extends to the top of the footer mast, and is overlapped by a “cap” portion of the knuckle assembly. There are three material combination choices suitable for this flashing unit. A dead soft aluminum base flange with neoprene or EPDM rubber cone/tube. 
     Each knuckle assembly comprises three die-cast aluminum parts, four hardware pieces and two seals. The cap piece is installed over the tube end and the anchor bolt is threaded into the integral hole in the framing member. A threaded hole in the top of the footer mast serves as the anchoring point. This requires two seals. One is a metal backed neoprene washer that is simply installed onto the anchor bolt. This seal is compressed when the bolt is tightened causing the necessary seal. A secondary safety seal gasket is installed on the top surface of the footer mast. Such neoprene gasket compresses between the inside of the cap and the footer mast. 
     The pivot bar is inserted through the holes in the cap. One end is knurled causing a friction fit into the hole in the cap. The yoke is attached securely, but is still free to pivot on the axis of the pivot bar. The final piece necessary to complete the assembly is the clamp. This piece is secured by means of two bolts. When tightened completely, it secures the framing beam in place. 
     The framing members are typically 6063-T6 extruded aluminum. The outside diameter of the framing member always stays the same, about 2.450″. When design loads are increased, the wall thickness increases for added strength. 
     The box-channel clip is preferably a zinc plated sheet metal part that clamps around the vertical beam at the appropriate height to hold the box-channel in place. It is secured by means of a bolt threading into a Pem-Nut which spreads the upper and lower wings, locking them into the box-channel. 
     The box-channel itself is installed horizontally between frames. The number of rows required is determined by the design load and the panel spanning capability. The channel is spring locked to the clip by hooking the top edge first, then pushing the bottom causing the clip tabs to flex far enough to snap in place. The spreader bolt is then screwed in to lock the clip onto the box-channel. Splice plates are used for end to end attachment of the channel. 
     The panels are installed across the box-channels and attached by means of self drilling through fasteners, or concealed retainer clips. 
     Although particular embodiments of the present invention have been described and illustrated, such is not intended to limit the invention. Modifications and changes will no doubt become apparent to those skilled in the art, and it is intended that the invention only be limited by the scope of the appended claims.