The present invention provides an apparatus and methods for curved troughs used in gutter systems. An arcuate trough is formed with a mounting structure that employs two folds, with one fold disposed between the other fold and the outer surface of the trough.

TECHNICAL FIELD 
   The present invention relates to rain and run-off collection and diversion systems and, in particular, to rain collection trough designs. 
   BACKGROUND OF THE INVENTION 
   Diversion of rain from buildings is a well-known and beneficial practice. For centuries, architects and builders have understood the benefits of diverting rain to forestall erosion, maintain structural stability, and preserve vegetation. In recent decades, a multitude of systems have been developed to divert rain from structures and homes. Typically, such systems have been placed beneath or adjacent to the roofline to allow collection and diversion of rain accumulated from across the surface area of the structure roof. Such systems are sometimes called “gutter” systems. 
   Typical gutter systems employ a trough structure that is either open along its length or covered by a deflector or hood to inhibit the collection of debris that would otherwise be swept into the system by the collected water. Gutter system troughs often exhibit a cross-sectional shape known as the “o-gee” (i.e., “OG”). Other gutter systems may employ troughs that are arcuate in shape with what is known as “half-round” being a common shape for such arcuate troughs. 
   When bearing the weight of accumulated water, arcuate troughs and, in particular, half-round troughs are less stable than the OG style trough. An OG trough has a flattened backside that supports the weight of accumulated water. In contrast, a trough with a curved back wall area contacts a small area of the facia board or other mounting surface of the building from which runoff is collected. Consequently, the force of the accumulated water weight is concentrated in a smaller area. Typically, most of the weight of a curved trough is borne at the site of attachment or, specifically, around the location where the mounting fastener penetrates the back wall of the trough. This is particularly true where the back mounting area of the trough is curved and lacks the flat rear mounting surface of an OG. In a trough with a curved mounting area, over time, the trough will tend to sag and may even pull from the facia board or other mounting surface to which it has been attached. These structural instabilities arise from the shape of arcuate troughs employed in gutter and rain collection systems. 
   What is needed therefore is an arcuate trough design that contemplates the loads imposed by the weight of water accumulated in the trough and provides added stability and load bearing capacity while retaining the aspect of curvature preferred by same. 
   SUMMARY OF THE INVENTION 
   The present invention provides an apparatus and methods for curved troughs used in gutter systems. An arcuate trough is formed with a mounting structure that employs two folds, with one fold disposed between the other fold and the outer surface of the trough. 


   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  depicts a prior art arcuate trough typically employed in gutter systems. 
       FIG. 2  depicts a prior art mounting area for the prior art trough of  FIG. 1 . 
       FIG. 3  depicts a preferred embodiment of the present invention. 
       FIG. 4  depicts a preferred embodiment of the present invention. 
       FIG. 5  depicts a preferred embodiment of a mounting structure employed in a preferred embodiment of the present invention. 
       FIG. 6  illustrates, in a preferred embodiment, a first step in formation of a preferred mounting structure in accordance with the present invention. 
   


   DESCRIPTION OF PREFERRED EMBODIMENTS 
   The term “arcuate” is to be understood to mean curved. For example, many gutter troughs are fashioned in what is called in the trade a “half-round” style. This is but one example of an arcuate trough. Other gutter troughs where the trough perimeter is curved in the mounting area of the trough should also be considered within the general category of arcuate troughs. 
     FIG. 1  depicts a prior art half-round trough  10  composed of trough material  11  shaped to have a rear lip  12  in a mounting area  14  and a front lip  16 . Mounting area  14  of trough  10  is depicted in enlargement in  FIG. 2 . As shown, rear lip  12  is devised by folding over trough material  11  to create a double thickness mount field  20 . A fastener then passes through mount field  20  to attach trough  10  to the building from which runoff is diverted. The fold is either inward toward the inside of the trough as shown or outward against the backside of the trough. In practice, although creation of a mount field  20  by folding trough material  11  over to double the material thickness at the point of attachment provides some added strength, it does not prevent sagging. Trough  10  will typically exhibit a tendency to sag or shift as, over time, the weight of borne water pulls the structure downward with more force than the mechanics of the trough mounting can reliably bear. As those of skill in the field recognize, the problem of weight-caused sag becomes more acute in larger troughs as the mechanical level arm through which the weight is applied increases downward forces. 
     FIGS. 3 and 4  depict a preferred embodiment of the present invention. In depicted trough  30  comprised from trough material  11 , a mounting structure  32  is depicted in accordance with the present invention. Mounting structure  32  exhibits at least two folds. A first (or outer) fold  34  in trough material  11  is imposed by bending trough material  11  at the upper extent of mounting structure  32  and a second (or inner) fold  36  is imposed at a lower extent of mounting structure  32  to create mounting field  20  on the backside of trough  30 . Those of skill will recognize that folds  34  and  36  may be creases, folds, or bends or similar impositions on material  11 . This creates a double metal layer (depicted by reference A) consisting of the thicknesses of the metal trough material of trough  30  and outer fold  34  and a triple metal layer (depicted by reference B) comprised of the thicknesses of the trough material, outer fold  34  and inner fold  36 . This also creates, in a preferred embodiment, gap  38  which is an optional feature of the present invention. The front containment wall border area of trough  30  of  FIG. 3  is depicted with an inwardly projecting containment shelf  39  that is described in co-pending U.S. application Ser. No. 09/880,412 owned by the assignee of the present invention. 
   The entire extent of mounting field  20  need not rest against the building from which runoff is collected. The assignee of the present invention has used an aluminum alloy as well as copper-based metals for trough material  11  but as those in the field will understand, other materials may be employed to advantage with the present invention. 
   In a preferred embodiment, outer fold  34  extends from apex  33  to apex  35  of inner fold  36  while inner fold  36  extends from apex  35  to its end  37 . To preserve clarity in the figures, end  37  of inner fold  36  is shown in  FIG. 6 . 
   There are several sizes of half-round gutter trough available. For example, the assignee of the present invention offers 6″ half-round troughs. These and other sizes of troughs may be fabricated in conformity with the present invention using standard sized materials (i.e., coil stock of approximately 11 and ⅞ inches in width in the Western U.S. and 11 and ¾ inches in parts of the Eastern U.S.). The use of standard sized materials with the present invention is of significant advantage in fabrication and cost administration. 
     FIG. 5  depicts a preferred mounting structure  32  penetrated by fastener  40  which may be a screw, nail, spike or other similar fastening device. Fastener  40  passes below the apex  33  of outer fold  34  and above apex  35  of inner fold  36 . 
     FIG. 6  illustrates, in a preferred embodiment, a first step in formation of mounting structure  32  in accordance with the present invention. In the preferred embodiment of the method, inner fold  36  is created first by folding over trough material  11  to the outside surface  39  of the trough. It should be understood that the process of forming a trough in accordance with the present invention may be implemented in a forming machine devised to impose the appropriate folds or bends in the proper sequence. Such forming machinery will generally also simultaneously form the trough itself. 
   Inner fold  36 , in a preferred embodiment, doubles over approximately 0.200″ of trough material  11  as measured from apex  35  of inner fold  36  to the end  37  of inner fold  36 . Inner fold  36  may double over between 0.050″ and 0.250″ of material with a fold over of 0.200″ being found to be preferable in light of the constraints of using standard sized materials in fabrication of trough  30 . Then preferably, approximately 1.0 inches below apex  35  of inner fold  36 , trough material  11  is then bent over again to create outer fold  34 . This is a preferred process for creating the double layer A and triple layer B. The recited dimensions have been found to be preferable by the assignee of the present invention to allow standard sized materials to be employed in the configuration of embodiments of the present invention. Those of skill in the field will note however, that other relative dimensions for folds  34  and  36  will also provide satisfactory results and mounting field  20  extending between apex  33  and apex  35  may, for example, be between ½ and 4 inches in extent from apex  33  and apex  35  and still use standard materials. Some may prefer to use specialized materials for fabrication of trough  30  and in those cases, mounting field  20  may exceed the range of between ½ and 4 inches from apex  33  of fold  34  to apex  35  of fold  36 . 
   Although the present invention has been described in detail, it will be apparent to those skilled in the art that the invention may be embodied in a variety of specific forms and that various changes, substitutions and alterations can be made without departing from the spirit and scope of the invention. The described embodiments are only illustrative and not restrictive and the scope of the invention is, therefore, indicated by the following claims.