Abstract:
A semiconical shaped roof ventilator comprising a base frame, a cover integrally formed on the base frame and upwardly extending therefrom, the base frame and cover capable of being efficiently manufactured from a single piece of material so as to have improved durability, and wherein the roof ventilator has improved air ventilation due to its semiconical shape.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This invention relates to roof vents, and more particularly to dormer ventilators for pitch roofs. 
         [0003]    2. Background Information 
         [0004]    Roof ventilation is an important consideration in building construction, particularly in home construction because inadequate or poor ventilation can cause condensation problems in the roof and otherwise significantly impair energy efficiency. Dampness from weather leads to condensation, which can cause damage to the structural or thermal properties of the roofing material. Roof ventilation is necessary to avoid such condensation problems. 
         [0005]    Another common problem is energy inefficiency in a home due to poor heat ventilation in the attic. The attic space of a home typically traps heat, whether externally from the sun or internally from a heating unit, which can result in excess heat buildup in the attic space. Excess heat in the attic space can cause the temperature in the rest of the house to increase. Thus, if the antic space becomes too hot, heat is transferred to the rest of the house, thereby requiring more energy consumption to cool the house. 
         [0006]    A common solution to these kinds of problems is to facilitate heat ventilation by the use of static roof vents. Various ventilation systems have been developed to ventilate excess heat that is trapped in the attic, including gable vents and dormer vents. These ventilation systems are intended to conduct excess heat and moisture out of the attic space. 
         [0007]    One type of ventilator is the cupola vent described in U.S. Pat. No. 2,737,876 to Smith. Because such cupola vent is mounted on the ridgeline of a roof, these types of vents do not provide optimal eaves-to-eaves ventilation. Another type of ventilator is described in U.S. Pat. No. 5,779,539 to Kolt, which is of a circular variety. The type of ventilator described by Kolt is not well suited to pitched roofs since, when mounted on the slope of a pitched roof, the vent sits at an angle to the roof and thus is susceptible to allowing rain to enter the roof through the vent. Moisture problems may be caused by rain entering through the vent. 
         [0008]    U.S. Pat. No. 2,692,548 to Knorr describes an attic access dormer vent that can be opened to provide access into the attic area below the roof. As described therein, the dormer vent is comprised of several different portions secured together to form a rectangular or square frame. Rectangular or square dormer vents of the type described in U.S. Pat. No. 2,692,548, in which the ventilation volume is constant, results in poor airflow. This is because such rectangular of square vents rely mainly on the external airflow to draw out the stagnant air in the attic. 
         [0009]    Further, ventilators of the of the type described in U.S. Pat. No. 2,692,548 is also inefficient and costly to manufacture. This is because such ventilators are made from several different panels of sheet metal that must be welded and assembled together. 
         [0010]    Generally, roof ventilators are commonly made of sheet metal or galvanized steel, fabricated by methods well known in the art. Typically, for example, a roof ventilator is prefabricated from a plurality of metal sheets that are spot welded together. This method of fabrication is costly and inefficient because such construction is labor intensive. 
         [0011]    Further, ventilators made by welding a plurality of metal sheets are also particularly prone to rusting at the seams. The unevenness of the welded seams tends to retain moisture deposits that cause accelerated rusting. 
         [0012]    Similarly in this regard, ventilators having flat ends tend to allow rainwater to concentrate in the flat area, resulting in rust and eventual deterioration of the back end of the vent. 
         [0013]    Not least, ventilators made from a mismatch of metal sheets invariably result in an unattractive construction, which detracts from the appearance of the roof. 
         [0014]    For the foregoing reasons, there is a need for a roof ventilator that can be efficiently made without welding from substantially a single sheet of material that is less costly to manufacture and assemble, less prone to rusting, more attractive in appearance, and which has improved ventilation. 
       SUMMARY OF THE INVENTION 
       [0015]    Therefore, it is an object of the present invention to provide a roof ventilator for improved ventilation of trapped air under the roof space of a building. 
         [0016]    It is an object of the present invention to provide a roof ventilator with improved drainage of water around the ventilator. 
         [0017]    It is an object of the present invention to provide a roof ventilator with improved resistance to rust by virtue of its shape. 
         [0018]    It is an object of the present invention to provide a roof ventilator with improved aesthetics. 
         [0019]    It is another object of the invention to provide an efficient method for manufacturing a roof ventilator in which certain portions can be made from substantially a single piece of material. 
         [0020]    It is an object of the present invention to provide an efficient method for manufacturing a roof ventilator without welding. 
         [0021]    The present invention is directed to an apparatus for roof ventilation that satisfies the need for a roof ventilator having improved ventilation. The present invention is also directed to a method for manufacturing a roof ventilator that can be efficiently made from substantially a single sheet of material that is less costly to manufacture and assemble. 
         [0022]    A roof ventilator according to the present invention comprises a base frame that is capable of mounting to the roof of a building, the base frame having an opening therein adapted to cooperate with an opening in the roof. Although the base frame can be of any geometric shape, in the preferred embodiment the base frame includes a front end, a rear portion, and two side portions, with the front end being wider than the rear portion, thus forming a trapezoidal shaped frame. When the base fame is mounted to a pitched roof, the roof ventilator lies on the slope of the roof with the front end in the direction of the eaves and the rear portion in the direction of the ridge. 
         [0023]    A cover is integrally formed on and upwardly extends from the base frame, such that the cover encloses the opening in the roof. In the preferred embodiment the cover has a frontal opening contiguous with the front end of the base frame. The frontal opening is semicircular in shape, which tapers into a rounded back end that is contiguous with the rear portion of the base frame. 
         [0024]    As shown in  FIG. 2 , the back end has curvilinear corners coming together to form a rounded back end. The back end also curves downwardly as shown in  FIG. 4 , adding to the roundness of the end. The rounded back end improves drainage of rainwater by diverting water away from the back portion of the roof ventilator. This is a significant improvement over the prior art having flat ends, since ventilators having flat ends tend to allow rainwater to concentrate in the flat area, resulting in accelerated rust and eventual deterioration of the back end of the vent. 
         [0025]    The tapering of the cover from the semicircular frontal opening into the rounded back end forms a semiconical shape. It is contemplated that the cover may embody a variety of semiconical shapes, some as described herein. 
         [0026]    Such semiconical shapes improve airflow in the roof ventilator because it functions as a kind of diffuser for attic ventilation. As air travels from the tapered rounded back end to the semicircular opening it will loose exit velocity, but there is also a corresponding increase in pressure. In other words, the roof ventilator recovers the pressure head (as well as reduce the kinetic energy) of ducted flow. For this application, there is semi-continuous flow from the attic to the outside, and the vent acts as a diffuser. As such, this change in pressure leads to better ventilation because more air is moved through per unit time. 
         [0027]    The roof ventilator further comprises a flange extending along a peripheral edge of the semicircular frontal opening of the cover. A plurality of louvers or slats is attached to the flange, extending in parallel across the frontal opening of the cover. Though the slats function to prevent rain, snow, and other atmospheric matters from entering the ventilator, the slats also have curvilinear blade portions to improve airflow. In a preferred embodiment of the invention, the plurality of slats includes at least one, though preferably a plurality of, apertures therein. The apertures improve heat ventilation by allowing heat to pass through the apertures to the outside. 
         [0028]    The roof ventilator can also include a screen mounted to the cover, the screen being mounted behind the plurality of slats to block ingress of debris or insects, and prevent other unwanted matters from entering the ventilator. 
         [0029]    A roof ventilator according to the present invention can be more efficiently manufactured by forming a frame base from a piece of sheet metal, which can be cut and stamped into a frame having a front end, a rear portion and two side portions, preferably forming a trapezoidal shaped frame. The cover is integrally formed with the frame base. The cover can be separately formed from a single piece of sheet metal and welded to the base frame. But, preferably, the cover and the base frame are formed from a single piece of sheet metal. Towards this end, it is to be recognized that the semiconical shapes of the roof ventilator is well suited to being made from a single piece of sheet metal. 
         [0030]    The roof ventilator includes a plurality of slats that can be formed as individual louvers that can be assembled to the roof ventilator separately. In the alternative, it is preferable that the plurality of slats are formed as an integrated combination from a single piece of sheet metal, so as to allow assembly of the plurality of slats as an integrated unit to the roof ventilator. In this way, the slats can be uniformly made for easy assembly to the frontal opening of the cover of the roof ventilator. 
         [0031]    A screen is formed and attached to the cover behind the slats for protecting the attic space from bugs, insects and debris. 
         [0032]    Though sheet metal is the preferred material of construction, it is within the contemplated scope of invention that other materials, including plastics, for example, can be used to construct the roof ventilator in accordance with the description herein. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0033]      FIG. 1  is a perspective view of an embodiment of the invention. 
           [0034]      FIG. 2  is a top view of an embodiment of the invention. 
           [0035]      FIG. 3  is a front view of an embodiment of the invention. 
           [0036]      FIG. 4  is a sectional view of an embodiment of the invention taken along line B-B in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0037]    Referring to  FIG. 1 , a roof ventilator  10  according to a preferred embodiment of the present invention is shown. Roof ventilator  10  includes generally a base frame  20 , a cover  40 , and a plurality of louvers or slats  60 . 
         [0038]    In the preferred embodiment the base frame  20  includes a front end  22 , a rear portion  24 , and two side portions  26 . As shown in  FIG. 1 , the front end  22  is wider than the rear portion  24 , thus forming generally a trapezoidal shaped frame. By way of example only, the proximate dimensions of the base frame  20  is 28 inches in length (l) and 36 inches wide (w 1 ) as defined in  FIG. 2 . One of skill in the art would recognize that the roof ventilator  10  can be of any proportionate size so as to accommodate various roof openings. 
         [0039]    The base frame  20  has an opening  28  therein defined by side portions  26  and rear portion  24 , the opening  28  adapted to cooperate with an opening in a roof. More specifically, the opening  28  will be defined by the contiguous edge  30  between the base frame  20  and the cover  40 . 
         [0040]    The base frame  20  is capable of mounting to the roof of a building (not shown). When the base fame  20  is mounted to a pitched roof, for example, the roof ventilator  10  lies on the slope of the roof with the front end  22  in the direction of the eaves and the rear portion  24  in the direction of the ridge. 
         [0041]    The cover  40  is integrally formed on the base frame  20 , such that the cover  40  encloses the opening  28  that cooperates with an opening in a roof. The cover  40  upwardly extends from the base frame  10  as best shown in  FIG. 1  and  FIG. 3 . 
         [0042]    The cover  40  has a frontal opening  42  that, in the preferred embodiment, is contiguous with the front end  22  of the base frame  20 . The frontal opening  42  is semicircular in shape. As shown in  FIG. 1 ,  FIG. 2  and  FIG. 4 , the frontal opening  42  tapers in height and width into a back end  44  that is contiguous with the rear portion  24  of the base frame  20 . By way of example only, the height (h) of the cover  40  as defined in  FIG. 3  is approximately 9 inches taken from the bottom of the base frame  20 , with the frontal opening  42  slanted at an angle of approximately sixty degrees (60°) from horizontal as shown in  FIG. 4 . The width (w 3 ) of the back end  44  is narrower than the widest distance (w 2 ) in the frontal opening  42 , such that the cover  40  tapers toward the narrow back end  44 . It would be recognized by one skilled in the art that the width, height, and angle dimensions of the cover  40  can be of various proportions so long as the roof ventilator works for its intended purpose as described herein. 
         [0043]    It is shown in  FIG. 2  that the back end  44  has curvilinear corners  46  coming together to form a rounded back end. Back end  44  also curves downwardly as shown in  FIG. 4 , adding to the roundness of the end. The rounded back end  44  improves drainage of rainwater by diverting water away from the back portion of the roof ventilator. This is a significant improvement over the prior art having flat ends. Ventilators having flat ends tend to allow rainwater to concentrate in the flat area, resulting in accelerated rust and eventual deterioration of the back end of the vent. The rounded back end  44  also facilitates manufacturing as described herein. 
         [0044]    The tapering of the cover from the wide semicircular frontal opening  42  into the narrower rounded back end  44  forms a semiconical shape. It is contemplated that the cover  40  may embody a variety of such semiconical shapes, as defined by the variable height and width of the cover  40 . For example, as the width (w 3 ) of the back end  44  is made increasingly shorter relative to the width (w 2 ) of the frontal opening  42 , the shape of the cover  40  approaches the geometry of a cone. Thus, in another preferred embodiment of the invention, the cover  40  has a semiconical shape defined by a semicircular frontal opening  42  that tapers into a point, wherein the point is centrally located in the rear portion  24  of the base frame  20 . 
         [0045]    The semiconical shapes of the cover  40  improve airflow in the roof ventilator  10  because it acts as a kind of diffuser. As air travels from the tapered section to the semicircular frontal opening  42 , it will increase in pressure. This increase in pressure leads to better ventilation because more air is moved through per unit time. 
         [0046]    The semiconical shapes of the cover  40  also improve water drainage around the roof ventilator  10 . When the roof ventilator  10  is mounted on the incline of a pitched roof, rainwater will flow around the tapered cover  40  and away from the frontal opening  42 . This helps to prevent rainwater from entering the attic space and causing moisture damage to the attic space. 
         [0047]    The angled frontal opening  42 , in the preferred embodiment approximately 60° from horizontal, also prevents rain from entering the attic space. For example, when the roof ventilator  10  is mounted on a pitched roof having a 60° slope, the face of the frontal opening  42  will be nearly perpendicular to the pitch of the roof. At that angle, the cover  40  provides optimal covering from vertical rainfall. 
         [0048]    The roof ventilator  10  further comprises a flange  46  extending along a peripheral edge of the frontal opening  42  of the cover  40 . A plurality of louvers or slats  60  is attached to the flange  46  by spot welding or by attachment means (not shown), such as screws or fasteners. The slats  60  extend in parallel across the frontal opening  42  of the cover  40 . The slats function to prevent rain, snow, and other atmospheric matters from entering the ventilator  10 . 
         [0049]    As best shown in  FIG. 4 , the slats  60  have curvilinear blade portions  62  to improve airflow. In a preferred embodiment of the invention, the plurality of slats  60  includes at least one, though preferably a plurality of, apertures  64  therein. The apertures  64  improve heat ventilation by allowing heat that might otherwise be trapped by the slats  60  to pass through the apertures  64  to the outside. In the preferred embodiment shown in  FIG. 1 , the apertures  64  are in the topmost slat  60 , since heat as it rises would tend to concentrate in the upper area of the cover  40 . 
         [0050]    The roof ventilator  10  can also include a screen  70 , shown in  FIG. 4 , mounted to the cover  40 , the screen  70  being mounted behind the plurality of slats  60  to block ingress of debris, insects or other unwanted matters from entering the ventilator  10 . 
         [0051]    The roof ventilator can be manufactured by forming a frame base  20  from a piece of sheet metal, which can be cut and stamped into a frame having a front end  22 , a rear portion  24  and two side portions  26 . In the preferred embodiment, the frame base  20  forms a trapezoidal shaped frame. The cover  40  is integrally formed on the frame base  20 . Although the cover  40  can also be separately formed from a single piece of sheet metal and welded to the base frame  20 , it preferable that the cover  40  and the base frame  20  are formed from a single piece of sheet metal. Towards this end, it is to be recognized that the semiconical shape of the roof ventilator  10  is well suited to being made from a single piece of sheet metal. 
         [0052]    Further, by making the roof ventilator frame base  10  and cover  20  from a single piece of sheet metal will reduce rust at the seams commonly associated with ventilators having welding seams. 
         [0053]    The roof ventilator  10  includes a plurality of slats  60  that can be formed individually, or preferably from a single piece of sheet metal. In this way, the slats  60  can be uniformly made for easy assembly to the flange  46  of frontal opening  42  of the cover  40 . A screen  70  is formed and attached, behind the slats  60 , to the cover  40  for protecting the attic space from bugs, insects and debris. 
         [0054]    This invention is not to be limited by the embodiments shown in the drawings and described in the specification, which is given by way of example and not of limitation, but only in accordance with the scope of the appended claims.