Abstract:
A roof structure for a building in the form of a cone shaped polygon is disclosed. The roof structure includes at least three multi-element trusses attached on corresponding ends to a vertically extending central column. Each of the trusses is rotationally displaced from adjacent ones of the trusses, as measured in a horizontal plane, preferably, by the same angle. Each of the trusses is inclined outwardly and downwardly from the central column to form a series of triangularly shaped roof segments between adjacent ones of the trusses and so as to provide the roof structure shape. The central column may be a vertically extending length of hollow pipe and is essentially non-load supporting, whereby a lower end of the column is vertically spaced above a support structure for outer peripheral edge portions of the trusses. The support structure may be a series of wood posts, a different one of which is attached on an upper end portion to an outer peripheral edge portions of a corresponding one of the trusses.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates to a roof structure for a building including a vertically extending essentially non-load supporting central column which is spaced above supporting structure for the roof structure, and at least three trusses joined on their inner ends to the column and extending radially outwardly and downwardly to the roof supporting structure. Each of the trusses is rotationally displaced in a horizontal plane from adjacent ones of the trusses to form at least three triangularly shaped roof segments of a cone shaped polygon configuration.  
           [0002]    Broadly speaking, cone shaped polygon roof structures are known in the prior art. See, for example, the gazebo roof disclosed in U.S. Pat. No. 4,739,594 granted to J. D. Langford et al. on Apr. 26, 1988 and the roof structure taught in U.S. Pat. No. 4,332,116 granted to H. A. Buchanan on Jun. 1, 1982. The gazebo roof structure of Langford et al. is made of eight triangularly shaped segments, each segment having two wood side beams of one inch by four inch board joined together at an apex and a series of radially spaced apart cross members. The side beams of the eight segments have inner ends which are mounted in U-shaped brackets secured around a central hub. The roof structure of Buchanan contains fifteen triangularly shaped segments, each segment having two side beams or roof components meeting at an apex, and a series of radially spaced apart cross members. The roof components are supported on their radially inner ends on a support plate which is welded to an upper end portion of a weight supporting central column which extends from floor to ceiling in the reference structure.  
           [0003]    None of the prior art roof structures are formed using multi-element truss members. While the gazebo roof structure of Langford et al. contains a non load supporting central hub, the fact that rafters or wood side beams are used severely limits the roof span and, consequently, limits the amount of floor space obtainable under roof. On the other hand, the much greater span of roof structure envisioned by Buchanan requires that his rafters must be supported not only on their radially outer ends by posts or columns, but also by a load supporting floor to ceiling central column in the center of the span.  
           [0004]    In the gazebo of Langford et al., adjacent ones of the reference roof supporting posts must be rigidly tied together by cross members to prevent the roof structure from sagging and, thereby, tilt the posts radially outwardly. This would have the effect of spreading the posts apart at their upper ends, therefore permitting the roof to sag and, ultimately, the building to collapse. The cross members thus prevent the upper ends of the posts from spreading apart and therefore prevent the roof from sagging.  
           [0005]    It would be desirable to have a cone shaped polygon roof structure of the size envisioned by Buchanan which can be entirely supported on and around an outer perimeter portion of the structure without need for a span interrupting central weight supporting column and without need for rigidly connecting upper ends of adjacent roof supporting posts together to prevent roof sag.  
           [0006]    By means of the present invention, these and other problems encountered in such prior art roof structures are substantially eliminated.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    It is an object of my invention to provide a novel truss reinforced cone shaped polygon roof structure.  
           [0008]    It is a further object of my invention to provide such a roof structure wherein a plurality of trusses are joined on corresponding ends to an essentially non-weight supporting central column which is elevated above support structure for peripheral end portions of the trusses so that the roof structure forms a free span over any selected diameter of the roof structure.  
           [0009]    Briefly, in accordance with my invention, there is provided a roof structure for a building including an essentially non-load supporting, vertically extending central column having a lower end spaced above a supporting structure of the roof structure. The roof structure further includes a plurality of at least three elongated and vertically inclined, multi-element trusses fixedly joined on innermost ends thereof to the central column. The trusses are rotationally displaced from one another in a horizontal plane. Each of the trusses extend radially outwardly and downwardly from the central column to an outer end portion thereof for mounting on the supporting structure at a level spaced below a lower end of the column. The plurality of trusses thereby defines a roof structure in the form of a cone shaped polygon.  
           [0010]    These and other objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description and attached drawings upon which, by way of example, only a preferred embodiment and certain modifications of the invention are illustrated.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 shows a perspective view of a corral having truss supported cone shaped roof structure, thus illustrating a preferred embodiment of my invention.  
         [0012]    [0012]FIG. 2 shows a top plan view of the roof structure of FIG. 1.  
         [0013]    [0013]FIG. 3 shows a plan view of four strips of corrugated roofing used on the roof structure of FIGS.  1 - 2 , thus illustrating how the strips are cut to form two segments of the roofing of the subject structure.  
         [0014]    [0014]FIG. 4 shows an end elevation view of a portion of the roofing strips of FIG. 3 showing overlapping edges of two adjacent ones of the strips and illustrating the corrugations therein.  
         [0015]    [0015]FIG. 5 shows a cross-sectional elevation view of the roof structure of FIGS.  1 - 2  as viewed along cross-section lines  5 - 5  of FIG. 2.  
         [0016]    [0016]FIG. 6 shows a perspective view of a fragment of the roof structure of FIGS.  1 - 2  and  5  as viewed along view-lines  6 - 6  of the latter mentioned figure.  
         [0017]    [0017]FIG. 7 shows an enlarged detail view of a portion of the roof structure of FIGS.  1 - 2  and  5 , the same as viewed in FIG. 5.  
         [0018]    [0018]FIG. 8 shows a top plan view of the roof structure portion shown in FIG. 7 with certain parts replaced and with corrugated metal roofing removed.  
         [0019]    [0019]FIG. 9 shows an enlarged detail view of a central portion of the roof structure of FIGS.  1 - 2  and  5 , the same as viewed in the latter mentioned figure.  
         [0020]    [0020]FIG. 10 shows an enlarged detail view of a fragment of the central portion shown in FIGS.  1 - 2  and  9 , the same as viewed in FIG. 2.  
         [0021]    [0021]FIG. 11 shows a cross-sectional view of the central portion of FIG. 9 as viewed along cross section lines  11 - 11  of the latter mentioned figure and with certain parts replaced.  
         [0022]    [0022]FIG. 12 shows a partially cross-sectioned elevation view of a portion of roof structure similar to FIG. 7, except modified to replace the corrugated roofing with a tarpaulin.  
         [0023]    [0023]FIG. 13 shows a top plan view of the roof structure portion of FIG. 12 with the tarpaulin removed.  
         [0024]    [0024]FIG. 14 shows a top plan view of a central portion of the roof structure of FIGS.  12 - 13 .  
         [0025]    [0025]FIG. 15 shows a partially cross-sectioned side elevation view of the central portion of FIG. 14.  
         [0026]    [0026]FIG. 16 shows a side elevation view of a portion of one of the trusses in the roof structure of FIGS.  12 - 15 .  
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0027]    Referring now to the drawing figures and, in particular, to FIGS.  1 - 2 , there is shown, in a preferred embodiment of my invention, a building structure, generally designated  20 , which includes a novel roof structure, generally designated  22 , in the form of a cone shaped polygon. While it can be readily adapted for many different uses, the structure  20  of the present example is shown in the form of a corral for confining animals such as horses or cattle. For this reason, the perimeter of the structure  20  is shown as being enclosed by a board fence of conventional type having a series of adjoining panels  24  and a standard latchable entrance gate  26 . It will be appreciated that the building structure  20  could include any number of different types of siding of well known type, as desired, depending, at least in some instances, on the purpose for which the structure is to be used. The roof structure  22  of the present example contains twelve triangularly shaped segments  28 , as viewed in plan (FIG. 2), and is fully supported on twelve posts  30  (FIGS. 1, 5 and  7 ) spaced on and around a perimeter of the roof structure. Each of the posts  30  are located at an intersection between different adjacent pairs of the segments  28 . The posts  30  are preferably constructed of wood and each post is preferably square in cross-section with a cross-sectional dimension of 6″ by 6″ and has a length of 13½ ft, a lower 3½ ft of which is preferably below grade in 2 cubic feet of concrete footing.  
         [0028]    Referring now to FIGS.  1 - 11 , details of the roof structure  22  are shown including a conventional corrugated sheet metal roofing  32  and a series of twelve steel trusses  34 , each of the trusses having an upper beam  34   a , preferably inclined at 22 degrees with the horizontal, and a lower beam  34   b , preferably inclined at a 16 degree angle with the horizontal. Each of the trusses  34  are rotationally displaced from adjacent ones of said trusses by an equal angle of displacement as measured in a horizontal plane and contain a series of vertically extending and radially spaced apart steel spacer members  36 , forming a series of truss sections between adjacent ones of the spacer members. In the present example there are four truss sections, each being 5″-6″ in horizontal length, and a like series of steel inclined or diagonally extending reinforcing members  38 , a different one of which is disposed in each of the truss sections. The beams  34   a  and  34   b  and spacer members  36  can be welded together at their intersections and may be constructed of standard 1½″×1½″ hollow box tubing, preferably being at least ⅛″ in thickness. The reinforcing members  38  can also be welded on their ends at intersections between the beams  34   a  or  34   b , as shown, and may be constructed of 1″×1″ standard box tubing of at least ⅛″ thickness. A radially outer and lower end of each of the inclined members is welded at an intersection between the lower beam  34   b  and a radially outer one of the spacer members  36  forming an outer end of a corresponding one of the truss section. Similarly, an upper radially inner end of each of the inclined members  38  is welded to an intersection between the upper beam  34   a  and a radially inner one of the spacer members  36  which forms an inner end of a corresponding one of the truss section.  
         [0029]    The outermost vertical spacer  36  of each of the trusses  34  extends below a corresponding one of the lower beams  34   b  along an outer facing side of a different one of each of the posts  30 , as shown in FIGS. 5 and 7, so that each of the outermost spacers can be joined to an upper end portion of a corresponding one of the posts by conventional fasteners such as nuts and bolts  40 . The upper beam  34   a  of each of the trusses  34  is welded to an upper end of a different one of the outermost vertical spacers  36  and extends outwardly beyond the outermost spacer into an end portion of a larger piece  42  of steel box tubing (See FIGS.  7 - 8 ), preferably about 6 inches in length and 2″×2″ in cross-section. Each upper beam  34   a , thus inserted into a corresponding box tubing piece  42 , is joined to the latter by a nut and bolt  44 .  
         [0030]    Referring now specifically to FIGS.  7 - 8 , the outermost end of each of the twelve box tubing pieces  42  is welded, as at  43  (FIG. 7), to an angular intersection between a pair of flat, rectangularly shaped steel mounting plates  45   a  and  45   b . In the present example, wherein the roof structure  22  contains twelve segments  28 , the interior angle between the intersecting plates  45   a  and  45   b  should be 150 degrees. The plates  45   a  and  45   b  are, in turn, fastened to opposing end portions of abutting 2″×6″ wood board peripheral trim members  47   a  and  47   b , respectively (See also  47  in FIG. 1), which trim members contain intersecting ends which are cut on a 105 degree angle of taper relative to their lengths. The trim members  47   a  and  47   b  can be fastened to the plates  45   a  and  45   b , respectively, with a series of wood screws  49 .  
         [0031]    Referring now specifically to FIGS. 2, 5,  7  and  8 - 9 , each of the segments  28  contain a series of radially spaced apart 2″×4″ wood board upper cross braces  49  of differing lengths which span between and abut adjacent pairs of the upper beams  34   a  of the trusses  34 . The cross braces  49  are held at each end in conventional saddle hangers  51  which are fitted over each of the upper beams  34   a  and are welded or otherwise suitably fastened thereto, as, for example, at welds  53  in FIG. 8. The cross braces  49  can then be secured to the saddle hangers  51  by means of suitable wood fasteners such as wood screws or nails  55 .  
         [0032]    The innermost end of each of the trusses  34  contains a vertical box tube spacer  46  which is joined to a corresponding innermost end of a corresponding one of the upper beams  34   a , lower beams  34   b  and incline members  38  by welds as shown in FIG. 9 at  48  and  50 . The spacers  46  are, in turn, fastened to and around a hollow cylindrically shaped steel central column  52  (See FIGS. 9 and 11) by means of three vertically spaced apart series of nuts and bolts  54 ,  56  and  58  (FIG. 9 only). In the present example, the column may be a 6″ diameter steel pipe, 4½′ long. In any event, the column  52  need only be long enough to permit joinder of the spacers  48  thereto so that the innermost ends of corresponding ones of the beams  34   a  and  34   b  and inclined members  38  can be welded to such spacers. Thus, the need for a floor to ceiling central column is eliminated, allowing the roof structure  22  to be a free overhead span across any diameter thereof. A disc shaped steel plate  60  (FIG. 9) is placed on an upper end of the column  52 .  
         [0033]    Over the plate  60  and innermost ends of the roofing  32  of the segments  28  is placed a cone shaped sheet metal cap  62  (See FIGS.  9 - 10 ), preferably about 2′ in diameter, to prevent rain and melt water from leaking between the roofing  32  along the outside surface of the column  52  into the corral below the roof structure  22 . The cap  62  may be formed by first cutting a disc shaped piece out of a flat sheet metal, then by cutting along a radius of the piece followed by lapping one of the resulting edge portions  64  over an opposing edge portion  65 , as shown in FIG. 10, to form the desired cone shape, as shown in FIG. 9. An elongated central vertical pin  66  with exterior threading on a lower end portion thereof may be inserted through central openings in the cap  62  and plate  60 . To stabilize the pin  66 , a second plate  68  is disposed within the column  52 , so as to be spaced below the plate  60  and is held in place by a nut  70  which is located thereunder around a lower threaded end portion of the pin  66  as shown in FIG. 9.  
         [0034]    Referring now to FIGS.  5 - 6 , a pair of radially spaced apart lower cross braces  72 , preferably made of angle iron, can be placed between adjacent pairs of the lower beams  34   b  to stabilize them. To this end, a flat, rectangular steel plate  74  is welded to an upper surface of the box tubing forming the lower beam  34   b  and, then, overhanging portions of the plate are secured to end portions of the lower cross braces  72  with suitable fasteners, such as a nut and bolt combination  76  as shown in FIG. 6. The resulting trusses  34  of the present example are each 22 feet in horizontal length between an outer face of any one of the posts  30  and a corresponding one of the innermost spacer members  52 . The diameter of the interior of the structure  20  of the present example is approximately 43′-9″ between opposing interior faces of opposing ones of the posts  30 . The interior height of the roof structure  22  varies from about 10 feet, as measured vertically along any one of the peripheral posts  30 , up to about 15′-6″ at the center of the roof structure between grade, taken at a base of any one of the posts  30 , and a lower end of the column  52 .  
         [0035]    Referring now to FIGS.  2 - 4 , to form the triangular segments  28  of the roofing  32 , four strips  78  of corrugated roofing sheet having lengths of 24 feet and widths of 38 inches can be laid side-by-side so that opposing sides of adjacent pairs of the strips have a overlapping corrugations  80  along their long dimensions (FIG. 4). The arrangement thus formed is shown in FIG. 3. To form a pair of triangularly shaped pieces of the roofing  32  to cover two of the segments  28 , the sheets  78  of FIG. 3 are cut along dashed cut lines  82  as shown The resulting central isosceles triangle, cut along the lines  82  in FIG. 3, forms one of the roofing pieces for covering one of the segments  28 . The remaining two right triangular pieces on opposite sides of the central triangle can be joined back-to-back along their sides  84  and, similarly, overlapping two inches to form the other roofing piece for covering a second one of the segments  28 . Each of the resulting segments  28  is laid between a different adjacent pair of trusses  34 . A standard ridge cap  85  overlaps adjoining segments  28  and is fastened to the wood cross hexes  49 .  
         [0036]    Referring now to FIGS.  12 - 16 , there is shown, an alternative roof covering comprising a flexible, waterproof, tarpaulin  86  which can be used to cover the roof structure  22  of the previous example, by making a few modifications, in place of corrugated sheet metal roofing  32 . One of the modifications is in the use of angle iron upper cross-braces  88  (See FIG. 16) between adjacent pairs of the upper truss beams  34   a  in place of the wood board cross braces  49  and saddle hangers  51  of the previous example. The upper cross braces  88  are bolted on end portions thereof to rectangular plates  90  welded to an upper surface of the upper beams  34   a  in the same manner as the cross braces  72  of the lower beams  34   b  are fastened to the plates  74 , as shown in FIGS.  5 - 6  and  16 . Only a pair of the upper cross braces  88  need be used to adequately stabilize the upper beams  34   a  when using the tarpaulin  86 , one of which upper cross braces is located in each of the two central sections of each of the trusses  34 , similar to the placement of the two lower cross braces  72  as shown in FIG. 5.  
         [0037]    The only other modifications to the roof structure of the previous example needed for the use of the tarpaulin  86  is that shown in FIGS.  12 - 13  wherein the mounting plates  45   a  and  45   b  and the wood trim members  47   a  and  47   b  of the previous example are replaced by elongate box tubing peripheral members  92  such as shown in FIG. 12. The peripheral members  92  are preferably 2″ by 2″ box tubing to match the box tubing piece  42  to which they are welded at their abutting ends as at  94  in FIGS.  12 - 13 .  
         [0038]    The circular tarpaulin  86  should be of sufficiently large diameter to permit outer edge portions to be wrapped around the peripheral members  92  and lapped back under the same as shown in FIG. 12 at  96 . Outer edge portions of the tarpaulin  86  contain a series of eyelets  98 , preferably about every 16 inches around the entire perimeter thereof. A length of cord  100  can be strung through each of the eyelets  98 . Each of the cords  100  is then strung between each of the eyelets  98  and a peripherally extending steel cable  102  which is strung around an outer edge portion and underneath each of the upper beams  34   a  through a suitable eye screw or eyelet  104  fastened or welded to each of the upper beams  34   a  (See FIG. 12). An eyelet  106  is placed at the center of the tarpaulin  86  through which the pin  66  can be extended as shown in FIGS.  14 - 15 . By using the tarpaulin  86  of the present example, the cone shaped cap  62  of the previous example will not be needed and can be omitted if desired, as indicated by its absence in FIG. 15.  
         [0039]    In conclusion, it will be apparent that the roof structure of my invention may contain as few as three triangular segments, as viewed in the plan. That is to say, these may be as few as three trusses  34  rotationally displaced from adjacent ones of the trusses, preferably by 120 degrees as measured in a horizontal plane, or as many more than three as considered practical, including, if desired, more than the twelve trusses and segments as contained in the roof structure  22  of the present example. In any case, it is preferable that horizontal angle of displacement of each of the trusses from adjacent ones of the trusses be equal around the entire roof structure.  
         [0040]    Although the present invention has been shown and described with respect to specific details of a certain preferred embodiment thereof, it is not intended that such details limit the scope and coverage of this patent other than as expressly set forth in the following claims, making allowance for reasonable equivalents thereof.