Abstract:
A method and apparatus for manufacturing and installing a roof structure, in which clay is formed into tiles which simulate wood shakes, and the tiles are attached atop a supporting surface in a predetermined manner in a substantially unrecognizable pattern. The tile configuration provides a structure which is light in weight yet is structurally sound, which lends itself to ready installation upon a wide variety of structures.

Description:
TECHNICAL FIELD 
     This invention relates in general to roofing, and particularly relates to the use of light weight yet structurally sound clay roof tile to simulate wood shake roofing, in a stacking configuration which includes cutting indicia to facilitate the stacking of the tile in a manner which discourages pattern repetition. 
     BACKGROUND OF THE INVENTION 
     In the field of roofing, it is well known to provide wood shakes, as roofing elements, in an overlapping manner for water diversion purposes. However, as may be understood, such wood shakes can have disadvantages, not least of which is their flammability. Furthermore, after sufficient weathering such wood shakes can tend to leak. However, consumers nevertheless have shown a preference towards such wood shakes, due to their desirable appearance. 
     Therefore, it has become known to provide simulated roof members, which simulate wood shakes but are comprised of nonflammable materials. However, such approaches nevertheless have disadvantages when used with materials other than wood. 
     When done with concrete, the material is typically cast in a lower mold only. The only contours possible on the upper surface are those created by the linear planing off of the wet material immediately after pouring, which can be limiting. Metal pressed products tend to be limited to shapes with identical contours on both top and bottom surfaces. 
     Other disadvantages can also become apparent if mass-produced simulation shakes are provided. In order to achieve a more realistic installed appearance, it is necessary to stagger the horizontal courses so that the edges of two adjacent horizontal courses do not align, both from a standpoint of appearance and for water drainage. To achieve this, it is known in the art that the first tile on the right end of each course (assuming that the tiles are being installed right to left) should be cut of a random length to create the desired random stagger. However, without the proper guidance (or incentive), installers will frequently create an unintentional and unwanted pattern, the most common of which is known in the art as “stair stepping”. 
     Therefore, it may be seen that there is a recognized need in the art to provide simulated wood shakes, which include improved weathering and strength capabilities, but can still be installed to provide a realistic appearance without recognized stacking patterns. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes deficiencies of the prior art by providing an improved tile, and method and apparatus for providing same, which includes improved structural capabilities, yet simulates a wood shake construction. 
     Therefore, it is an object of the present invention to provide an improved roof construction. 
     It is a further object of the present invention to provide an improved roof tile. 
     It is a further object of the present invention to provide an improved roof tile which has improved structural capabilities. 
     It is a further object of the present invention to provide an improved roof tile which is relatively light in weight. 
     It is a further object of the present invention to provide an improved roof tile which simulates a wood shake but is composed of vitrified clay. 
     It is a further object of the present invention to provide an improved roof tile which simulated a wood shake even when viewed from its “butt” edge. 
     It is a further object of the present invention to provide an improved roof tile laying systems. 
     Other objects, features, and advantages of the present invention will become apparent upon reading the following detailed description of the preferred embodiment of the invention when taken in conjunction with the drawing and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a pictorial view of a rotatable mold  10 , including multiple tile-shaped cavities  11 A,  11 B for receiving clay. 
     FIG. 2 is an illustrative end view of a mold  10  such as shown in FIG. 1, viewed along its axis of rotation and illustrating its interaction with a reciprocating top mold member  14 , as it works with the base mold member  10  in converting clay bats  13  into tile forms which, upon further processing, will provide tile according to the present invention. 
     FIGS. 3 a  and  3   b  are pictorial views of “sister” tile configurations  20 A,  20 B, respectively. 
     FIG. 4 is a side view illustrating the overlapping nature of the tiles  20  when they are installed atop a supporting surface  42 , and secured thereon by nails or other suitable fasteners  41 . 
     FIG. 5 is a top plan illustrative view of a “generic” tile  20  with cutting indicia molded therein which can be used to guide the installer to create a predetermined yet typically imperceptible stacking pattern. In FIG. 5, a cut along dotted line  50  would be following the cut mark “5”. FIG. 5 also shows the provision of three nail holes  19 . 
     FIG. 6 is an illustrative view illustrating the stacking configuration according to the present invention, which although having a repetitive pattern, is substantially imperceptible to the typical human eye. 
     FIG. 7 is a top plan view of a tile configuration  20 A according to the present invention. 
     FIG. 8 is a cross-sectional view of the tile in FIG. 7, taken along line  8 — 8 . 
     FIG. 9 is a top plan view of a tile  20   b  according to the present invention. 
     FIG. 10 is a cross-sectional view of the tile of FIG. 9, taken along line  10 — 10 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Overall Discussion 
     Generally described, the configuration, and method and apparatus for forming same, of the tiles according to the present invention is now generally discussed. 
     FIGS. 1 and 2 illustrate the general manufacturing process for providing tiles  20  according to the present invention, that being the use of rotating mold  10 , which accepts clay bats  13  and forms them into tile shapes such as shown in FIGS. 3A and 3B. After being dried and kiln fired, these tiles can be installed in an overlapping manner as shown in FIG. 4 atop an inclined support surface such as  42 . As shown in FIG. 5, “cut marks” or other suitable indicia are molded into the clay shapes such that, upon suitable cutting by a installer (not shown), they can be installed in the configuration such as shown in FIG.  6 . 
     The Manufacturing Process 
     Reference is now made to FIGS. 1 and 2, which combine to illustrate the general concept according to the present invention of manufacturing tiles according to the present invention, by molding raw unmolded clay into two similar tile forms suitable for oven firing. 
     Clay with a moisture content sufficient to provide adequate plasticity (18-22% has been found acceptable) is extruded from a pugmill/extrusion machine in a column (not shown). As may be understood, the extrusion process evacuates substantially all of the air from the clay mixture to discourage delamination. The column is then cut into short lengths to create the blanks or “bats”  13  for pressing. 
     The press structure includes a rotatable drum  10  having a hexagonal cross-section and defining six outwardly-directed drum faces. Two (lower) molds are provided in on each drum face, totaling 12 molds. To provide an aesthetically pleasing variation on the installed appearance of the tiles (discussed in detail below), one “A” and one “B” mold cavity  11 A,  11 B is provided on each face. The net result is a 50—50 mix of the two profiles in production. 
     As shown in FIG. 2, the clay bats enter the press and are deposited on the lower molds when the molds are in the 10 o&#39;clock position. The drum  10  is configured to rotate about a substantially horizontal axis, such that upon drum rotation the bats  13  are moved into the 12 o&#39;clock position, where the top mold member  14  comes down and presses the bats into the shape of the tile, and then withdraws upwardly. The drum then rotates the pressed tile forms  20  to the “2 o&#39;clock” position, where a vacuum picker (not shown) such as known in the art moves in and simultaneously trims off the excess clay around the edges of the tiles and punches nail holes as needed, It removes the tiles from the drum face and deposits them on drying trays (not shown) that are passed under the picker on a synchronized conveyor. 
     The wet tiles, on their individual dryer trays, are then sent through a dryer where the moisture content is reduced to less than 1%. The dry “greenware” is then transported to the kiln for firing. The vitrified tiles, in the forms shown in FIGS. 3A and 3B, are then placed directly into their shipping pallets. 
     The Tiles and Their Details 
     As noted above, the tiles according to the present invention are produced in a manner such as to provide a 50—50 production of two “sister” tile configurations, referenced at this point forward as  20 A and  20 B configurations. Each of these configurations is interchangeable within a stacking configuration described in further detail; however, the decorative upper surfaces are somewhat different in appearance. If the tiles are installed randomly, perceptibly repetitive patterns will be discouraged, especially if the tiles are installed as discussed below. 
     Reference is now made to FIGS. 3A and 3B, each of which illustrates a single tile  20 A,  20 B, respectively. As may be seen by these drawings, the upwardly directed face, as well as the butts of each of the tiles, contain abrupt changes in elevation and setback to simulate three (3) individual pieces of wood shake. These changes create the desired shadowing and appearance to simulate wood shakes. 
     As shown in FIG. 3A, tile  20 A includes a center section  22 A, a “left” (as viewed from the butt end) section  23 A, a right section  24 A, and a sidewardly-extending engagement member  25 A, which extends to the left of member  23 A, and defines a channel  26 A and includes an upwardly-directed ledge portion  27 A. The tile  20 A includes a “head” end  31  A, a “butt” end  32 A, a left edge  33 , and a right edge  34 . The sections  22 A,  23 A and  24 A all include simulated woodgrain designs  28 A, at their upper surfaces and at their butt edges, which gives each tile the appearance of three side-by-side conventional wood shake members, which in practice tend to have their upper surfaces at varying heights due to differences in shake thicknesses and other natural variances. In the tile  20 A shown in FIG. 3A, the center member  22 A is somewhat lower than its two adjacent members  23 A,  24 A, and includes an inclined portion  29 B. The center portion  22 A does not extend towards the “butt” end of the tile as much as its two adjacent members  23 A,  24 A, giving a “set-back” appearance, simulating installed wood shakes. Referring momentarily to FIGS. 7 and 8, the tile  20 A also includes a downwardly-directed side engagement member  37 A. 
     Referring now to FIG. 3B, the tile  20 B shown in that figure includes a center portion  22 B, a left portion  23 B, a right portion  24 B, a sidewardly-extending upwardly-directed engagement member  25 B (defining a channel  26 B and including an upwardly-directed engagement ledge  27 A). The tile  20 B includes a head end  31 B, a “butt” end  32 B, a left edge  33 B, and a right edge  34 B. As in tile  20 A, tile  20 B includes the three members  22 B,  23 B, and  24 B, which simulate three adjacent wood shakes. Inclined face portions  29 B (two shown in FIG. 3B) compensate for the fact that the left section  23 B, and the right section  24 B each slope slightly towards the relatively higher center portion  22 B. As in the case of tile  20 A, tile  20 B does not have an uniform “butt” edge, instead its section  22 B extends outwardly somewhat relatively to its two adjacent sections  23 B,  24 B. As shown in FIGS. 9 and 10, tile  20 B likewise include a sidewardly-extending downwardly-directed engagement member  37 B, which includes a downwardly-directed drip ridge  39 B, which extends the length of the member  37 B. It should be noted that tile  20 A likewise has a drip ridge, although it is not numbered in FIG.  8 . 
     It may be understood that the sidewardly-extending interlocking members  25 A,  25 B, of the tile members allow for the interlocking of laterally adjacent tile members to form a horizontal course as discussed in detail below. It should also be noted that, as shown best in FIGS. 3A,  3 B,  7  and  9 , the interlocking members  25 A,  25 B, of the tiles  20 A,  20 B, respectively, are “set back” a distance “SB” (see FIGS. 7 and 9) from the butt ends of their adjacent sections  23 A,  23 B, respectively. This provides an improvement over the known prior art, as the “interlocking” interface illustrated in FIG. 8 (between the solid line downwardly-directed interlocking member  37 A and the dotted-line member  35 A) is “hidden” somewhat by the overhanging nature of the downwardly-directed interlocking member  37 A. 
     An important attribute of this tile is that it is light in weight, as defined by the requirement of having an installed weight in the order of less than  6  pounds per square foot. In order to have the irregular contours of a wood shake, while also maintaining a uniform wall thickness to control unwanted additional weight, the bottom surfaces of the tiles are not solid like some prior art configurations, but instead include the use of strategically-placed structural ribs and a substantially consistent shelf thickness to provide a lightweight yet structurally sound tile configuration. 
     Reference is now made to FIGS. 7-10, which provides some further details regarding the configuration of the two top members  20 A,  20 B. As may be seen, in each of these configurations, a plurality of structural support ribs extend downwardly from what could be referred to as the main body or “shelf” of each of the tiles. Four of these structural support ribs  35  are substantially coparallel and are located to correspond with the highest points on the top of the tile. The provision of structural rib locations within the tile at locations immediately beneath the topmost “peaks” extending from top surface of the tiles provides superior strength when subjecting the tile to flexural strength testing or actual field conditions, where the tiles must support foot traffic. The remaining rib is a “butt” rib  36  which extends along the butt edge of each of the tiles. Unlike the coparallel ribs  35 , which are each substantially straight, the butt ribs includes a number of “jogs” which correspond to the jogged nature of the butts of the tiles. 
     As discussed in further detail below, the tiles  20 A,  20 B are typically installed horizontally in interlocked courses, with each horizontal course overlapping the one immediately below it. The overlap is typically three (3) inches, although other overlap lengths are contemplated without departing from the spirit and scope of the present invention. Each of the tiles  20 A,  20 B, is designed so that the rear edge of the upper surface is both level and the highest elevation of the tile. This provides a level resting surface  21  ( 21 A for tile  20 A and  21 B for tile  20 B) for the structural support ribs of the overlapping tiles, discouraging unwanted rocking motion under load and minimizing any possible fulcrum points that might promote breakage. However, the gaps and shadows that are expected in a wood shake roof are maintained at the butts  32 A,  32 B, of the tiles, such that the two overlapping tiles have irregular clearance. As shown best in FIG. 10, the main “body” or “shelf” of the tile members includes a substantially consistent thickness. The side portions  23 B,  24 B of the tile  20 B are of a substantially consistent thickness, yet taper towards the center of the tile, in order to divert as much water as possible from the joints that occur between adjacent tiles. 
     Reference is now made to FIG. 5, which generally illustrates the use of indicia placed on the tiles in the form of recessed slits extending a distance from the head end of the tiles. As discussed in detail later, such indicia facilitates perceptibly random lateral orientation of the horizontal courses relative to each other. 
     The Installation Process 
     In order to achieve a more realistic installed appearance, it is necessary to stagger the horizontal courses so that they do not appear to be have a regular spacing. To achieve this, it is known in the art that the first tile on the right end of each course (understanding that the tiles are installed right to left) should be cut of a random length to create the desired random stagger. However, left to their own devices, the installers will frequently create an unintentional and unwanted pattern, such as stair stepping. 
     To avoid this, as shown in FIG. 5, the present invention provides a plurality of numbered marks (eight in one preferred embodiment) on the upper edge of the tile to serve as a cutting guide just prior to the installation process. Although these marks (known generically as “indicia”) are placed upon the top surface of the tile, they are concealed during the installation process by the overlap as shown in FIG.  4 . 
     Reference is now made to both FIGS. 4 and 6, which combine to illustrate the tile installation or “stacking” process according to the present invention. In FIG. 4, the tile are overlapped as discussed above, and attached to a supporting surface (such as plywood) by nails or other suitable fasteners. 
     Reference is now made specifically to FIG. 6. A course  100  of tiles  20  begins with a full uncut tile  20  with its uncut right edge (corresponding to mark #1) aligned along the alignment edge line  61 . The second course  200  is started with a tile cut on mark #2 and laid with its cut edge along the alignment edge line  61 , the third course  300  with a tile cut on mark #3 and laid with its cut edge along the alignment edge line  61 , and so on through the eighth course  800 . Then the sequence is repeated. The numbers are placed to the left of the cutting mark so that they can be referenced when the installer returns to start the next course. This provides a predetermined yet random appearing pattern without the need of any printed diagram, measuring tools or the possibility of accidental unwanted patterns. Furthermore, this tends to discourage alignment of the side edges of the tiles, which is not preferred due to drainage reasons. One important feature of the invention is the provision of all the cutting marks to the right of the two leftmost coparallel structural ribs. This assures that at least two ribs will remain after cutting is complete, which will be recognized as advantageous in that stable tile placement is encouraged. 
     It may be understood that other layouts of cutting marks could also be practiced without departing from the spirit and scope of the present invention. 
     CONCLUSION 
     Therefore it may be seen that the present invention overcomes deficiencies in the prior art by providing a tile which can be produced in mass quantities, yet has the appearance of traditional wood shakes with the structural properties of fired clay. The present invention also provides an improved stacking configuration which allows for the use of a predetermined stacking pattern which nevertheless results in a stacked configuration which appears random to the typical observer. 
     While this invention has been described in specific detail with reference to the disclosed embodiments, it will be understood that many variations and modifications may be effected within the spirit and scope of the invention as described in the appended claims.