Patent Publication Number: US-2022213702-A1

Title: Concrete form and related method of creating a cantilever reveal

Description:
FIELD OF THE INVENTION 
     The present specification relates generally to concrete formwork, and specifically to a concrete form for the creation of a cantilever reveal in concrete stairs. 
     BACKGROUND OF THE INVENTION 
     Concrete is one of, if not, the most ubiquitous and enduring building materials. It can be used in many ways, for example, to create mass structures, such as dams, and produce decorative finishes, such as polished concrete surfaces. Regardless of the ways in which concrete may be used, a form or formwork is required to utilize concrete as a building or ornamental medium. 
     Forms or formwork may be temporary or permanent moulds into which concrete is poured. Traditionally, timber, plywood or particle board is used to build, on site, a mould that defines a desired shape of the concrete to be poured within it. Accordingly, the construction of a form or formwork is specialized based on the dimensions and esthetic requirements of the resulting structure. 
     In the case of constructing concrete stairs, standard configurations of forms and formwork have been used for many years. Recently, however, it has become fashionable to incorporate specialized esthetic features, such as a “cantilever reveal”, which gives the illusion that the concrete stair or set of stairs are floating. The reveal feature is typically accomplished by using standard forms or formwork for stairs and by either manually applying a rigid item that is the height of the reveal, during the pouring of concrete, to create the reveal feature; however, this technique does not allow the concrete technician to properly towel under the rigid item to create a smoothly finished reveal feature. These known processes are cumbersome and do not accomplish the sleek and tailored finish required to create the illusion of floating stairs. 
     Accordingly, there is a need for improvements in the art to create a cantilever reveal in concrete stairs in an efficient and accurate manner. 
     SUMMARY OF THE INVENTION 
     According to an embodiment of the present invention, there is provided a concrete form, comprising: a riser piece, including a top end and a bottom end; a cove piece, the cove piece including a distal end and a proximate end, the proximate end positioned on the bottom end of the riser piece at a perpendicular angle to the riser piece; and a reveal piece, the reveal piece positioned on the distal end of the cove piece projecting at a perpendicular angle to the cove piece, such that the reveal piece and the riser piece are parallel to one another. 
     According to a further embodiment, the present invention provides for use of one or more concrete forms to construct a cantilever reveal. 
     According to a further embodiment, the present invention provides a method of constructing a set of concrete stairs, the method comprising: constructing at least one concrete form, the at least one concrete form comprising, a riser piece, including a top end and a bottom end; a cove piece, the cove piece including a distal end and a proximate end, the proximate end positioned on the bottom end of the riser piece at a perpendicular angle to the riser piece; and a reveal piece, the reveal piece positioned on the distal end of the cove piece projecting at a perpendicular angle to the cove piece, such that the reveal piece and the riser piece are parallel to one another; affixing the at least one concrete form to at least one stringer; and pouring concrete within boundaries of the at least one concrete form and the at least one stringer. 
     Other aspects and features according to the present application will become apparent to those ordinarily skilled in the art upon review of the following description of embodiments of the invention in conjunction with the accompanying figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The principles of the invention may better be understood with reference to the accompanying figures provided by way of illustration of an exemplary embodiment, or embodiments, incorporating principles and aspects of the present invention, and in which: 
         FIG. 1  is a back perspective view of a concrete form according to an embodiment; 
         FIG. 2  is a back view of the concrete form of  FIG. 1 ; 
         FIG. 3  is a side perspective view of the concrete form of  FIG. 1 ; 
         FIG. 4  is a bottom perspective view of the concrete form of  FIG. 1 ; 
         FIG. 5  is a back perspective view of the concrete form of  FIG. 1 ; 
         FIG. 6  is a close up view of a series of concrete forms according to an embodiment; 
         FIG. 7  is a top perspective view of the series of concrete forms of  FIG. 6 ; 
         FIG. 8  is a front perspective view of the series of concrete forms of  FIG. 6 , with environmental features removed; 
         FIG. 9  is a further top perspective view of the series of concrete forms of  FIG. 6 , with environmental features removed; 
         FIG. 10  is a close up, front perspective view of the series of concrete forms of  FIG. 6 ; 
         FIG. 11  is a perspective view of the series of concrete forms of  FIG. 6 , into which concrete is being poured, with environmental features removed; 
         FIG. 12  is a perspective view of the series of concrete forms of  FIG. 6 , into which concrete is being poured, with environmental features removed; 
         FIG. 13  is a perspective view of the series of concrete forms of  FIG. 6 , into which concrete is being poured, with environmental features removed; 
         FIG. 14  is a close up, front perspective view of the series of concrete forms of  FIG. 6 , into which concrete has been poured and a concrete finisher is troweling under one of the series of concrete forms; 
         FIG. 15  is a perspective view of the series of concrete forms of  FIG. 6 , into which concrete has been poured and a concrete finisher is troweling, with environmental features removed; 
         FIG. 16  is a perspective view of a series of finished concrete steps featuring a cantilever reveal according to an embodiment, with environmental features removed; 
         FIG. 17  is a perspective view of a series of finished concrete steps featuring a cantilever reveal according to an embodiment, with environmental features removed; 
         FIG. 18  is a close up, perspective view of a series of finished concrete steps featuring a cantilever reveal, made using prior art devices and methods; and 
         FIG. 19  is a close up, perspective view of a series of finished concrete steps featuring a cantilever reveal, made using a concrete form similar to that of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     The description that follows, and the embodiments described therein, are provided by way of illustration of an example, or examples, of particular embodiments of the principles of the present invention. These examples are provided for the purposes of explanation, and not of limitation, of those principles and of the invention. In the description, like parts are marked throughout the specification and the drawings with the same respective reference numerals. The drawings are not necessarily to scale and in some instances proportions may have been exaggerated in order to more clearly depict certain features of the invention. 
     According to embodiments as shown in  FIGS. 1 to 17, and 19 , a concrete form may be assembled as a single concrete form or a series of concrete forms to create a mould into which concrete may be poured in order to construct a single concrete stair or a set of concrete stairs, respectively, with a cantilever reveal. Cantilever reveals, such as cantilever reveal  16100 ,  17100  and  19100 , are an esthetic feature, which gives the illusion that a concrete stair or set of concrete stairs are floating. 
     A concrete form may be constructed from materials which provide the mechanical strength and durability to withstand the weight and moisture of poured concrete. According to an embodiment, concrete form  1000  may be made from wood, such as timber, plywood or particle board. In other embodiments, concrete form  1000  may be constructed of a combination of wood, aluminum, steel, other plastics, metals or composites or a combination of suitable materials. Manufacturing costs, desired lifespan, and reusability may also be considerations in informing the choice of materials and construction technique and other design choices of concrete form  1000 . 
     According to an embodiment as shown in  FIGS. 1 to 5 , concrete form  1000  includes a riser piece  1100 , a cove piece  1200  and a reveal piece  1400 . Riser piece  1100  is composed of a plank of wood, such as timber, plywood or particle board and has a rectangular shape. Riser  1100  may be of any width, as is known in the art, to withstand the weight of poured concrete. Further, riser  1100  may be of any length and height that corresponds with the desired width and riser, respectively, of a single concrete stair or set of concrete stairs. 
     Riser piece  1100  also includes a top end  1101  and a bottom end  1102 , on which a proximate end  1202  of cove piece  1200  is affixed. Proximate end  1202  of cove piece  1200  is positioned on bottom end  1102  of riser piece  1100  at a perpendicular angle  1300  to riser piece  1100 . Cove piece  1200  may be affixed to riser piece  1100  by any means known in the art, such as by use of nails, screws or adhesive compounds, that ensures secure and impermeable attachment of riser piece  1100  to cove piece  1200 . Impermeable attachment is important to ensure that concrete poured into concrete form  1000  does not seep between riser piece  1100  and cove piece  1200 , which would result in an irregular edge and may make removal of concrete form  1000  difficult. Similar to riser piece  1100 , dimensions of cove piece  1200  may be of any length and depth that corresponds with the desired width and cove, respectively, of a single concrete stair or set of concrete stairs. Further, perpendicular angle  1300  ensures that a riser and cove of a concrete stair or set of concrete stairs are constructed at right angles. 
     Cove piece  1200  also includes a distal end  1201 , opposite proximate end  1202 , on which reveal piece  1400  is positioned. According to a preferred embodiment, reveal piece  1400  and cove piece  1200  are constructed from a single piece of material, such as aluminum, steel or plastic that is bent such that reveal piece  1400  projects at a perpendicular angle  1500  to cove piece  1200  and so that reveal piece  1400  and riser piece  1100  are parallel to one another. Like riser piece  1100  and cove piece  1200 , dimensions of reveal piece  1400  may be of any length and height that corresponds with the desired width and height of cantilever reveal, respectively, of a single concrete stair or set of concrete stairs. Further, perpendicular angle  1500  ensures that a cove and cantilever reveal of a concrete stair or set of concrete stairs are constructed at right angles, and that a riser and cantilever reveal of a concrete stair or set of concrete stairs are parallel. 
     According to an embodiment as shown in  FIGS. 6 to 15 , a series of concrete forms are assembled to create a mould into which concrete may be poured to construct a set of concrete stairs, such as set of concrete stairs  16000 ,  17000  and  19000 , with a cantilever reveal, such as cantilever reveal  16100 ,  17100  and  19100 . The series of concrete forms are comprised of at least one of concrete form  1000 . As is known to an individual skilled in the art, dimensions of each concrete form  1000  should be constructed and assembled relative to one another to reflect the desired rise (vertical height) and run (horizontal length) of a stair or set of stairs. Accordingly, when constructing concrete form  1000 , rise and run measurements should first be determined (and, if necessary, in compliance with relevant jurisdictional building codes) to ascertain the appropriate dimensions of each stair&#39;s rise (i.e., the sum of the height of riser piece  1100  and reveal piece  1400 ) and run (i.e., the horizontal distance between each riser piece  1100 ). 
     Once concrete form  1000  is constructed, it is affixed to at least one stringer  7000 . Stringer  7000  may be cast-in-place or pre-cast concrete, stone, brick, masonry material or wood structure that supports concrete form  1000  when pouring concrete and, once the poured concrete cures, provides structural integrity to a concrete stair or set of stairs. According to an embodiment, riser piece  1100  of at least one concrete form  1000  is affixed to stringer  7000  by way of screws and reinforced by a plank of wood; however, stringer  7000  may be affixed to concrete form  1000  by way of any connection mechanism or material known in the art to provide the appropriate strength and durability to withstand the weight and moisture of poured concrete. According to an embodiment shown in  FIG. 8 , two concrete forms  1000  may each be affixed to one of two stringers  7000  at one side and to the other concrete form  1000  on its other side, thereby creating at least one concrete stair with two cantilever reveals. According to a further embodiment, two of three concrete forms  1000  may be affixed to one of two stringers  7000  at one side and to a third concrete form on its other side, thereby creating at least one concrete stair with three cantilever reveals. 
     Prior to pouring concrete into concrete form  1000 , there are a number of methods known in the art to further support concrete formwork against weight of poured concrete, to increase the strength of concrete once it has cured and improve the removal of a concrete form once concrete has set. For example, at least one brace  13000  may be affixed to at least one concrete form  1000  along a pitch of the set of concrete steps to support a weight of poured concrete. Further, to provide additional structural support and longevity to a cured set of concrete stairs, prior to affixing at least one of concrete form  1000  to at least one stringer  7000 , footings  6100  and rebar grids  6200  may be laid in accordance with known methods and using materials known in the art. Concrete form  1000  may also be coated or covered with a liner or release agent  12000 , which prevents concrete from sticking to concrete form  1000  and enables concrete form  1000  to be easily removed once concrete sets. 
     Finally, once all structural components and concrete form  1000  are assembled, concrete may be poured within the mould defined by the at least one concrete form  1000  and the at least one stringer  7000 . According to an embodiment as shown in  FIGS. 11 to 15 , concrete  11000  is transported to the site and shovelled into the boundaries defined by at least one concrete form  1000  and at least one stringer  7000 , filling the top most concrete form first and then subsequent concrete forms below it. Concrete  11000  may be comprised of any appropriate mixture and proportion of aggregate (e.g., sand, gravel, crushed stone, etc.), binder (e.g., cement) and water known in the art for constructing concrete stairs. As concrete is poured into each concrete form, as is known in the art, concrete form may be hammered or vibrated to drive out air bubbles and then troweled to level concrete, in order to create a smooth cantilever reveal. In contrast, use of prior art methods and devices, as shown in  FIG. 18 , result in a concrete stair or set of stairs, such as concrete stair  1800 , that has a cantilever reveal  18100  that is bumpy, rough, and contains ridges that diminish the esthetic appeal and detracts from the “floating stair” effect. Once the concrete is set up long enough to support its own weight, concrete forms  1000  may be removed. Concrete may still require further time to cure fully into a set of concrete stairs, such as set of concrete stairs  16000 ,  17000  and  19000 , with a cantilever reveal, such as cantilever reveal  16100 ,  17100  and  19100 . 
     Various embodiments of the invention have been described in detail. Since changes in and or additions to the above-described best mode may be made without departing from the nature, spirit or scope of the invention, the invention is not to be limited to those details but only by the appended claims.