The roof shingle system of the present invention includes rows of shingle elements having parallel, slanting lower edges that are aligned to divert the flow of water away from areas where high flow volumes are not desired toward areas where high flow volumes will not cause harm. Because water flowing down a surface will tend to adhere to that surface, the water flowing down the surface of the shingle system of the present invention will tend to follow the slanting lower edges of the shingle elements in the direction of the slanted edges so as to provide a way to control the flow of water on the surface of a roof.

CROSS REFERENCES TO RELATED APPLICATIONS  
       [0001]    This application claims the benefit of U.S. Provisional Patent Application No. 60/184,309 filed Feb. 22, 2000. 
     
    
     
       FIELD OF THE INVENTION  
         [0002]    This invention relates to roof coverings and in particular to a roof system that diverts the flow of water in a pattern of flow that avoids roof areas that are susceptible to leakage or water damage.  
         BACKGROUND OF THE INVENTION  
         [0003]    Leaking roofs are a common problem for homeowners. Roof damage is often caused by leakage around openings such as skylights or leakage in high flow areas such as valleys between gables. Repairing such damage is often difficult, dangerous and expensive. Prior attempts to alleviate the effects of uncontrolled flow from roofs have met with limited success.  
           [0004]    Common prior art roof systems develop problems because their drainage is totally uncontrolled. The flow of rain water from a roof having only a single gable and no penetrations such a skylight is very simple. Rain water flowing from such a simple roof takes a direct path down to the eaves and gutters of the roof. The flow of water from a roof having intersecting gables and openings such as sky lights is much more complex. The flow of water accumulates at gable intersections and around openings. A casual observation of the effects of the flow of water in nature quickly provides one with an impression of the erosive effects of uncontrolled water flow. Uncontrolled water flow upon roof structures has similar erosive effects. Rain water flowing off of a complex roof builds up in valleys between gables and runs in an uncontrolled fashion near parapet walls and chimneys and all along the edges of eaves. Provisions such as flashing for resisting the flow of water in high flow areas eventually fail under the pressure of repeated high volume energetic flow and expose materials that are susceptible to water damage. The transfer of water flowing from a complex roof to a gutter system is deficient because the gutter system must be adapted to accept uneven and uncontrolled flow. Prior roofing systems have not been designed to provide the optimal transfer of water from a roof to a gutter system, but rather, gutter systems have had to be adapted to accommodate the flow of water as dictated by the roof structure.  
           [0005]    Even though a primary function of a roof is to protect a structure from the intrusion of water, the effective transfer of water from a prior art roof is not among the requirements that drives the design of a prior art roof. The pattern of drainage from a prior art roof is not optimized by design, but results from the architectural shape of the roof. The architectural shape of the roof is driven by esthetics and the internal geometry of the structure. Very little consideration is given to water flow when a prior art roof is designed. With a prior art roof, water simply follows an obvious downward path. A prior art roof will often have an accumulation of debris accumulation in the valleys between gables as well as debris in the gutter. This causes a moisture retention problem in the valleys and at the edges of eaves. Prior art roofing systems also require the periodic maintenance of flashing, parapet walls and chimneys where high volume energetic water flow often occurs. Consequently, prior art roofs fail in their main purpose of preventing the intrusion of the elements into a structure because they are not designed to manage the flow of rain water.  
           [0006]    Prior art roof systems are also vulnerable to leaks during extreme weather. Snow and debris accumulate in the same areas that water tends to accumulate. Even if a roof is in good condition, problems often arise at the extremities of a roof system, especially in open valleys, parapet walls and the edges of eaves adjacent to clogged gutter systems.  
           [0007]    One solution to the these problems would be to design roofs that have complex fluid dynamic shapes that are adapted to optimize the flow and transfer of rain water. No doubt this could make for a fascinating project for an architect and it is even possible that such a design project could produce fascinating and compelling shapes. However, it is unlikely that a practical solution gaining widespread acceptance in middle class residential neighborhoods would result from a theoretical project directed at creating fluid dynamic roof designs.  
           [0008]    What is needed is a roofing shingle product that can be arranged in an array of shingles that will direct water away from vulnerable areas of a roof such as valleys between gables or penetrations and then also direct it to predetermined drainage areas where water flow will not cause damage. An array of such shingles would direct water in a predetermined pattern rather than being limited to having water to merely follow the slope of the roof. Such a roof shingle, for use in an array of shingles could be easy to manufacture and install.  
         SUMMARY OF THE INVENTION  
         [0009]    The shingle system of present invention meets this need for improved drainage by providing a means to direct and control the flow of water as it flows down from a roof surface. In its simplest form, the roof system of the present invention includes rows of shingle elements having parallel, slanting lower edges that are aligned to divert the flow of water away from areas where high flow volumes are not desired toward areas where higher flow volumes will not cause harm. Because water flowing down a surface will tend to adhere to that surface, the water flowing down the surface of the shingle system of the present invention will tend to follow the slanting lower edges of the shingle elements in the direction of slant thereby providing a means for directing the flow of water on a roof.  
           [0010]    A roof structure surface could be envisioned as being defined by set of contour lines that have constant elevation and a set of grade lines that are normal or perpendicular to the contour lines. As rain water flows down from a roof structure, it will have a direction of flow that is parallel to the grade lines and perpendicular to the contour lines of the roof. Stated more simply, on a roof surface, water will flow down hill.  
           [0011]    However, the purpose of the present invention is to exploit a fluid flow phenomenon known as the “Coanda Effect”. Water flowing on a surface tends to adhere to that surface, and when flowing water encounters an edge, it resists flowing off of that edge. Accordingly, if water flowing down a surface encounters an edge that is oriented at an angle in relation to the contour line, the direction of flow will be altered to following the direction of the edge as the water follows the edge. So then, while standard roof shingles have bottom edges that are parallel to roof contour lines and normal to roof grade lines, a pattern of shingles of the present invention will have lower edges that are all aligned at an angle in relation to the contour line of the roof. Flowing rain water that encounters the angled lower edges of the shingles changes direction and follows those slanted lower edges.  
           [0012]    In its preferred embodiment, the shingle system of the present invention includes shingles that each have a base portion that includes an upper head lap section and a lower butt lap section. The head lap section of each shingle is usually covered from above by an overlapping butt lap section of an adjacent shingle. The butt lap section of the shingle includes two layers of overlapping shingle elements having slanted lower edges. The slanting lower edges are substantially parallel to each other and slant at an angle relative to the contour lines of the roof. These slanted lower edges are are also parallel with each other. Where the slanted lower edges terminate, the water continues on its angular path to followe the next slanted lower edge of the next shingle. By using shingles of the present invention, rain water on a roof can be directed at an angle relative to the grade line across the surface of the roof. Even limited applications of shingles of the present invention on only a portion of a roof can substantially direct water away from vulnerable areas. The invention shingle could be made of the same materials as other roof coverings such as aluminum, asphalt, wood, copper or composites such as cement composites or any other suitable roofing material. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The invention and its many attendant objects and advantages will become better understood upon reading the following description of the preferred embodiment in conjunction with the following drawings, wherein:  
         [0014]    [0014]FIG. 1 is a plan view of the invention roof shingle.  
         [0015]    [0015]FIG. 2 is a side view of the invention roof shingle.  
         [0016]    [0016]FIG. 3 is a front edge view of the invention roof shingle.  
         [0017]    [0017]FIG. 4 is a plan view of invention roof shingle.  
         [0018]    [0018]FIG. 5 is a plan view of invention shingle showing direction of water flow.  
         [0019]    [0019]FIG. 6 is a top view of a roof with invention shingles showing the direction of water flow.  
         [0020]    [0020]FIG. 7 is a perspective view of a roof with invention shingles showing the direction of water flow. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    [0021]FIG. 1 shows an invention roof shingle  10 . As can be better seen in left side view of FIG. 2 and lower edge end view of FIG. 3, roof shingle  10  generally includes a base shingle  14  that forms a head lap section  4  at its upper end and forms the base for a butt lap section  6  at its lower end. Butt lap section  6  further includes a first shingle  8 A 1  layered on top of base shingle  14  and a second shingle  8 A 2  layered on top of first shingle  8 A 1 . As can be seen in FIG. 1, first shingle  8 A 1  includes a saw tooth pattern of slanted lower edges  9 . In a similar fashion, second shingle  8 A 2  includes a saw tooth pattern of slanted lower edges  16  that are aligned and parallel to edges  9 .  
         [0022]    The flow of water  23  across invention shingle  10  is illustrated in FIG. 4. As can be seen in FIG. 4, water flow  23  moving down second shingle  8 A 2  adheres to the surface of second shingle  8 A 2  and encounters slanted lower edges  16 . While adhering to the surface of second shingle  8 A 2 , most of water flow  23  diverts to move in a direction substantially parallel to slanted lower edges  16 . In a similar fashion, additional streams of water introduced by falling rain drops along with some of original water flow  23  moves across shingle  8 A 1  and encounter slanted edges  9  and are also mostly diverted along those edges. In this way a flow vector is established that is angled with respect to the slope of the roof. FIG. 4 also shows that slanted lower edge  16  will be slightly offset from the next adjacent slanted lower edge  9  of shingle  8 A 1 . This slight offset facilitates the transfer of flowing water as the stream of flowing water transitions from following slanted lower edge  16  to following slanted lower edge  9 .  
         [0023]    [0023]FIG. 5 provides a plan view which illustrates how invention shingle  10  may be positioned in relation to other invention shingles. When many shingles such as shingle  10  are attached to the surface of a roof using fastening systems well known in the art, water flow is redirected as described above so that water flow over the entire surface of a roof my be diverted away from vulnerable areas.  
         [0024]    [0024]FIG. 6 shows and entire roof system in plan view. The application of rain water on a roof surface such as the roof illustraited in FIG. 6 is very uniform and very dispersed. Therefore, the flow of water on a roof structure is initially not concentrated in high volume energetic flows. Rain water striking the surface of the roof shown in FIG. 6 is dispersed very evenly and randomly across the surface of the roof. After striking the roof, the water forms a very large number of very small slow moving streams of trickling water. Because of the highly dispersed and unconcentrated nature of this pattern of flow, it is relatively easy to change the direction of the flow of water that is flowing or rather trickling down the surface of a roof.  
         [0025]    The roof system shown in FIG. 6 includes intersecting gables  18  and  20 , gable ridges  18 A and  20 A, valleys  22  and  24 , dormer roof  26 , down spouts  28 , flow of water  30  and example water flow concentration zones  40  which are represented by directional arrows. FIG. 6 illustrates the directing of the flow of water that can be accomplished by using shingles of the present invention. For example, flow  30  is directed away from valleys  22  and  24  by patterns of invention shingles such as shingle pattern  46 . Water therefore is diverted away from vulnerable valleys such as valleys  22  and  24  and valley metal  22 . Flow  30  is also directed away from gable edges  42  by invention shingles such as is shown in shingle pattern  46  toward water flow concentration areas  40  and on to down spouts  28 . In a similar way, water flow is directed away from dormer  26 . A lesser concentration of water falls off of dormer gable eaves  38  and onto roof  36  and is channeled away from parapet walls  32  and toward down spout  28 . Heavy concentrations of water  40  are no longer flowing in the low areas of the roof structure, nor are they flowing in valleys. All roof water flow terminates at gutter  48  and down spouts  28 . Shingles  46  could be arranged to form a closed valley  24  over the top of valley metal  22 . High concentrations of roof water  40  flow into gutter  46  at the high point of the gutter system, maintaining a high volume of water at beginning of gutter where with prior art shingles little water would be flowing. Arrows  44  illustrate the direction of water flow in the gutter system. High concentrations of water  40  are established by the by placing opposite right hand and left hand patterns of shingles.  
         [0026]    [0026]FIG. 7 provides a perspective view of invention directional shingles  111 ,  112 ,  114  and  116  installed on a roof structure  104  of a house  102 . Roof structure  104  includes a valley  106 , an edge  107  and a peak  108 . Three sets of directional shingles are used on roof structure  104 . A first set of shingles  111  is located adjacent to edge  107  and includes shingles having steeply angled lower edges of at least 45 degrees. First set of shingles  111  are arranged with their lower edges slanting away from roof edge  107  so as to divert water away from roof edge  107 . A second set of shingles  112  has a relatively shallow lower edge angle of approximately 30 degrees. Located higher on roof structure  104  is a third set  114  whose shingles have a steeper lower edge angle of approximately 37 degrees. Near the top of roof structure  104  is a fourth set of shingles  116  comprised of shingles having a steep lower edge angle of approximately 45 degrees.  
         [0027]    Set of shingles  112 , set of shingles  114  and set of shingles  116  are arranged so that their lower edges are angled in a progressively more shallow manner near the lower portions of the roof structure surface. With this arrangement as flowing water first follows the edges of set of shingles  116 , it assumes a direction of flow that is at a first angle of approximately at 45 degrees with respect to the grade line. As flowing water leaves set of shingles  116  and enters set of shingles  114 , it takes on a direction of flow that is at a second, larger angle of approximately 53 degrees with respect to the grade line. Finally, as water leaves set of shingles  114  and enters set of shingles  112 , it changes direction from a path that is at a third, even larger angle of approximately 53 degrees with respect to the grade line of the roof to a path that is at an angle of approximately 60 degrees with respect to the grade line of the roof. By diverting the flow of water on the roof by angles that are progressively greater in relation to the grade line of the roof, it is possible to divert water from a large portion of a roof surface to a relatively small portion of the lower edge of the roof. In this way, roof shingles of the present invention having differently angled lower edges can be arranged to transfer water from a large area to a relatively small collecting zone.  
         [0028]    [0028]FIG. 7 also illustrates how the pattern of lower edges set at angles can create an illusion of a roof valley at a virtual valley line E. This illusion of a valley where none is actually present is an example of how shingles of the present invention can be used to create interesting visual effects on a roof surface to give the appearance of a contour where no contour is present. It should also be apparent to those skilled in the art that shingles having slanted lower edges can be made so that the slanted lower edges are barely visible or are highly visible. Where slanted lower edges are barely visible, the visual effect of a contour where none is present will not occur. Where slanted lower edges are highly visible, the visual effect of a contour will be very evident. The term virtual valley is somewhat misleading since water will actually tend to flow toward virtual valley E on roof structure  104  as if it were a true valley. As water flow direction arrows C indicate, rain water flowing down roof structure  104  will tend to flow toward virtual valley line E as if it were a true valley such as valley  106 . As shown in FIG. 7, water will tend to flow to high capacity gutter S where almost all of the water from that portion of the roof can be collected. Rain water falling upon zone A shown in FIG. 7 would not be captured by gutter S. However, that amount of rain water would include only a small portion of the rain falling upon roof structure  104 . Substantially all of the rain water falling upon roof surface  104  shown in FIG. 7 between valley  106  and edge  107  would flow into gutter S. Moreover, because of the arrangement of invention shingles on roof structure  104 , water will tend to flow away from valley  106  and toward virtual valley E. Virtual valley E is a much more appropriate location on roof structure  104  to have a concentrated flow of water. A concentrated flow of water at valley  106  would tend to damage roof structure  104 . However, no such concentrated flow of water will occur in valley  106  of roof structure  104 . In fact, almost no water will flow in valley  106 . Because of the placement of oppositely angled directional shingles on either side of valley  106 , water will flow away from valley  106  as if it were a raised area such as peak  108 . This demonstrates how various types of directional shingles can be used to manage and control the flow of water across the surface of a roof structure.  
         [0029]    As can be seen from the forgoing description, patterns of invention shingles can be employed to control the flow pattern across an entire roof or in local areas of a roof to solve local flow problems. All of this flow management capability is based on the tendency of water to adhere to a surface and the use of that property to redirect water flow from an undesirable location on a roof to a more preferred location on a roof. By using patterns of shingles of the present invention, the pattern of flow of water on a pitched shingled roof can be established as a matter of design choice, thereby improving the performance roof structures as they perform their most basic function and also thereby significantly extending the useful life of many roof structures.  
         [0030]    Obviously, in view of the numerous embodiments described above, numerous modifications and variations of the preferred embodiments disclosed herein are possible and will occur to those skilled in the art in view of this description. For example, many functions and advantages are described for the preferred embodiments, but in some uses of the invention, not all of these functions and advantages would be needed. Therefore, I contemplate the use of the invention using fewer than the complete set of noted functions and advantages. Moreover, several species and embodiments of the invention are disclosed herein, but not all are specifically claimed, although all are covered by generic claims. Nevertheless, it is my intention that each and every one of these species and embodiments, and the equivalents thereof, be encompassed and protected within the scope of the following claims, and no dedication to the public is intended by virtue of the lack of claims specific to any individual species. Accordingly, it is expressly to be understood that these modifications and variations, and the equivalents thereof, are to be considered within the spirit and scope of the invention as defined by the following claims, wherein,