Abstract:
An insulated concrete form (ICF) is disclosed having opposed, spaced-apart foamed plastic panels with a plurality of unique protrusions on an inner surface, are held in spaced apart relationship with novel separators and easily fitted and removed connectors, including framing studs which are conveniently installed to provide secure attachment points for installing interior and exterior finishes, and rebar support boots which retain structural rebar in position spaced from contact with ground surfaces.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates generally to a system for constructing insulated walls, and more particularly to an insulated concrete form system for constructing insulated concrete walls for a building, dwelling or other insulated structure.  
       BACKGROUND OF THE INVENTION  
       [0002]     Insulating a concrete wall is desirable to minimize heat losses through the wall. One conventional method of insulating a concrete wall entails constructing a wood framework on the inside surface of the constructed wall and filling the openings in the framework with batt-type insulation. Another conventional insulation technique involves attaching foamed plastic panels to a pre-constructed concrete wall. Yet another technique for constructing an insulated concrete wall is accomplished by pouring uncured concrete into a form made of a plurality of interconnecting foam blocks. Systems using inter-connected foam blocks to form the wall are known in the construction industry as an insulated concrete form (ICF).  
         [0003]     Insulated concrete forms are typically constructed from a foamed plastic and usually have a generally rectangular shape to facilitate interconnection. In a desirable variation thereof, separate extruded flat foamed plastic insulation boards are supported in an aligned, spaced opposing arrangement, forming constructed ICF&#39;s which define the thickness of the wall and forms the outer surfaces of the wall. As rows of such constructed formed ICF&#39;s are stacked, horizontal and vertical metal reinforcing bars (rebar) are installed inside the cavity. When the required height of ICF forms is attained, concrete is poured into the cavity defined between the insulation boards forming the walls of the ICF. After the concrete has cured, the concrete and rebar act as the structural members of the building. The foamed plastic insulation, when combined with the concrete, can provide a thermal rating to the overall wall assembly in ranges exceeding R 15 .  
         [0004]     One of the main problems with currently available ICF systems is that most of them are costly as they typically use an excessive amount of concrete, and some are awkward to work efficiently with. Furthermore, many prior-art ICF panels have a propensity to wobble or distort due to an inherent lack of rigidity and structural stability. These prior-art ICF panels thus require a lot of bracing and often need to be repaired due to blowouts.  
         [0005]     It is highly desirable to provide a new and innovative design for insulated concrete forms that would overcome at least some of the perceived deficiencies in the prior art designs, and therefore an object of the present invention is to provide an insulated concrete form that overcomes at least some of the deficiencies of prior art ICF systems.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention provides an ICF system that includes two or more opposed foamed plastic panels arranged having facing interior surfaces between which concrete can be poured. The foamed plastic panels can be generally straight or curved, and have generally flat exterior surfaces which are arranged about parallel to each other, with facing interior surfaces having a plurality of unique protrusions. The protrusions are preferably shaped like truncated pyramids although other shapes are possible. The protrusions on the interior surfaces are preferably aligned in horizontal rows and vertical columns, and facing interior surfaces of panels have protrusions arranged in facing opposing alignment.  
         [0007]     Thus, an aspect of the present invention provides an insulated concrete form system for constructing an insulated concrete wall, the system including first and second opposing panels. The first and second panels are held in spaced apart arrangement by separators which are arranged between one or more facing ends of facing protrusions, defining a cavity into which rebar may be installed and into which concrete is poured. Connectors are arranged to secure spacers in place between facing protrusions and to assist the retention of panels in generally parallel alignment when subjected to the hydraulic forces of the poured concrete. Spacers are generally formed from foamed plastic such as the plastic comprising a panel. To resist formation of voids, spacers are preferably tear drop, cylindrical, or elliptical shaped, with flat ends to engage facing protrusions of the panels.  
         [0008]     In a preferred aspect of the present invention vertically arranged rebar is supported in place by a rebar support boot for use with an insulated concrete form. The rebar support boot comprises a polymeric body, an upwardly facing cavity in the body for receiving a bottom end of a vertical piece of rebar, and a plurality of vanes extending into the cavity for engaging and securing a bottom end of the rebar to the rebar support. In one embodiment thereof the bottom surface of the body of the rebar support boot comprises a protrusion for resisting movement of the support along the earthen ground during installation of the rebar. The polymeric rebar support boot retains the bottom ends of vertically arranged rebar from engaging the earthen ground surface, so that upon pouring the concrete within the bottom layer of an insulated concrete form, the rebar will not engage the ground surface but will be insulated from direct contact with the ground and otherwise encased within the formed concrete wall.  
         [0009]     In a further embodiment of the present invention a novel connector is provided for retaining a spacer in place between opposing panels. In one embodiment the connecter comprises an elongate rod having an entry end and an enlarged head at the opposite end. The entry end of the rod is passed through preformed holes in the spaced panels at a position where opposing panel protrusions are retained spaced apart with a spacer, with the entry end exiting from the exterior surface of the second panel. The enlarged head resists passage through the exterior surface of the first panel and a quicklock washer is applied to the entry end of the rod exiting from the exterior surface of the opposing second panel to retain the panels and spacer in connected spaced alignment. In a preferred embodiment the enlarged head seats against a large washer or the like for maximizing the surface area engaged on a foamed plastic panel, and the quicklock washer comprises an off-perpendicular releasable jam washer. The rod can be formed from any suitable metal or the like. Generally it is preferred to use large washers at each end of the rod to engage the exterior surfaces of the panels between the head and the quicklock washer. In a preferred embodiment the rod is removed after the concrete wall has sufficiently cured to retain self support and the hole that remains is sealed with a foamed plastic sealant.  
         [0010]     In still another embodiment of the invention, a novel framing stud is provided for fastening inner or outer finishes to a structural element of a wall assembly made using an insulated concrete form system. The framing stud comprises a shaft having an entry end and a opposite end, with two or more bulbous enlargements along its length. The entry end of the shaft is generally pointed, with the shaft gradually increasing in diameter to a first bulbous enlargement, then decreases to the nominal shaft diameter before increasing again in diameter to form another bulbous enlargement and then back again to the nominal shaft diameter. Additional bulbous enlargements may be formed in the same manner. The opposite end of the shaft comprises a generally flat, washer-like head spaced distally along the shaft from the last bulbous enlargement. The arrangement of adjacent bulbous enlargements along the shaft enable convenient penetration through the foamed plastic panels, with the bulbous shape of the enlargements providing the dual function of firmly anchoring the stud in the poured concrete and resisting being pushed out of position by the pressure of the liquid poured concrete. Upon cure of the poured concrete, the framing stud can be nailed or screwed into anywhere along its head. The framing stud of the invention is preferably formed from plastic or the like, and installed prior to pouring concrete. The framing stud provides a novel arrangement for fastening a finish to the surface of the insulated wall.  
         [0011]     Yet another aspect of the present invention provides a wire-twister tool for use in quickly tying wires which secure horizontal rebar to vertical rebar used in an insulated concrete form system, the tool comprising: a mounting shaft adapted to be mounted in a chuck of rotary-type tool, and a head connected to the mounting shaft, the head including one or two pairs of diametrically opposed parallel wire holes adapted to engage and twist together two wire ends.  
         [0012]     The present invention is inexpensive to manufacture, uses an efficient amount of concrete, and is very strong and stable, thus requiring very little bracing. The ICF system of the invention thus facilitates the construction of insulated concrete walls. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which:  
         [0014]      FIG. 1  is an isometric perspective view of an insulated concrete form system in accordance with an embodiment of the present invention;  
         [0015]      FIG. 2  is a side elevation view of a foamed plastic panel with a plurality of protrusions on an interior surface in accordance with an embodiment of the present invention;  
         [0016]      FIG. 3  is a top plan view of the foamed plastic panel of  FIG. 2 ;  
         [0017]      FIG. 4A  is a side/front elevation view of a rebar support boot for use with an ICF system;  
         [0018]      FIG. 4B  is a top plan view of the rebar support boot of  FIG. 4A ;  
         [0019]      FIG. 5A  is a side elevation view of a framing stud for use with the insulated concrete form system of the present invention;  
         [0020]      FIG. 5B  is a top view of the framing stud of  FIG. 5A ;  
         [0021]      FIG. 6A  is a side view of a wire-twister tool for use in conjunction with the insulated concrete form system of the present invention; and  
         [0022]      FIG. 6B  is a top view of the wire-twister tool of  FIG. 6A . 
     
    
       [0023]     It will be noted that throughout the appended drawings, like features are identified by like reference numerals.  
       DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0024]      FIG. 1  illustrates an insulated concrete form (ICF) System  10  in accordance with an embodiment of the present invention. The ICF system  10  includes two spaced-apart, opposing foamed plastic panels  20 , arranged generally parallel to form an insulated concrete wall of about constant thickness. It should be understood that even though a generally parallel arrangement is illustrated, non-parallel arrangements are contemplated as within the scope of the invention. The panels are spaced apart to define a cavity  12  into which rebar is installed and into which uncured concrete is poured, as will be described in greater detail below.  
         [0025]     The foamed plastic panels  20  are illustrated as nominally about four foot in height, with two sets of such panels stacked vertically to form an about eight foot high wall. The panels can be interconnected horizontally and vertically to form a length of wall, although the panels can be manufactured in various desirable lengths and/or widths. For the purposes of this specification, it should be expressly understood that panel means either a single foamed plastic panel or a plurality of interconnected foamed plastic panels forming one or both sides of the ICF. As persons of ordinary skill in the art will readily appreciate, the present invention can be applied to single panels of any dimension or to a plurality of interconnected panels.  
         [0026]     The panels can be formed from any suitable foamed plastic, but preferably from an Expanded Polystyrene (EPS). EPS is a typical material for an ICF system. The panels are made with a height of about four feet, a length of about sixteen feet and a thickness of about four inches, although as noted above, these dimensions may of course vary.  
         [0027]     Each panel  20  has an exterior surface  22  and an interior surface  24 . The exterior surface  22  of each panel is illustrated as substantially straight, although the panels can be manufactured in curved form. The panels  20  are perforated with holes  26  through which connecting devices, such as the fastener stud and the quick disconnect device of the invention, may be inserted in a manner to be described below.  
         [0028]     The interior surface  24  of each panel has a plurality of formed protrusions  30 , as shown in  FIG. 1 . These protrusions  30  are preferably truncated pyramids having a square base, although the shape of the formed protrusions may be varied as would be understood by a person skilled in the art based on such factors as ease of manufacture such as extrusion and/or hot-wire formation, ability to accommodate separators, ability of the ICF to withstand side stresses, ease of flowing concrete into the ICF, and engineering dictates. Thus, although truncated square-based pyramids are illustrated as a preferred mode, it is to be understood that the protrusions could also be practically any shape provided it satisfies the above criteria, such as for example block-shaped and/or rectangular-based pyramids. The protrusions  30  are preferably aligned in horizontal rows  32  and vertical columns  34 . The foamed plastic panels with protrusions can be manufactured by numerous means and methods, the more common of which are extruding or hot wire forming, which are both well known in the art. As shown in  FIG. 1 , the protrusions of the opposed panels face one another so that when concrete is poured, the cured concrete would appear to be a waffle-like shape if the foam were to be stripped away.  
         [0029]     The foamed plastic panels  20  are manufactured with perimeter channels  36  into which a slat  38  of plywood or other rigid material may be inserted in order to align adjacent panels. The perimeter channels are dimensioned to accommodate any required or desired size of aligning material. In a preferred embodiment, the perimeter channels are about three quarters of an inch deep to accommodate an about one and one half inch wide plywood slat between adjacent panels.  
         [0030]     The foamed plastic panels  20  are separated using separators  40 . Separators are generally used as specified by the engineer, depending upon the thickness, height and length of the proposed wall. Generally, the thicker the concrete wall, the more spacers will be used. It is contemplated that spacers may be used between every aligned protrusion of opposing panels, but typically when the wall thickness is nominal, separators are utilized only on some of the formed protrusions. The spacers are illustrated as being cylindrical while the protrusions are illustrated as truncated pyramids which provide a flat contact surface on each side against which the cylindrical separators engage. Truncated pyramids are relatively easy to form by standard extrusion and hot-wire forming techniques. The foamed plastic panels can be extruded in the form of peaks and valleys, which can then be formed into protrusions of the desired shape by means of a hot-wire or other shaping instrument or procedure.  
         [0031]     The panels  20  are held together by connectors  42  which pass through the respective holes  26  in the panels  20 . The connectors  42  penetrate through the separators  40 . As illustrated in  FIG. 2 , each connector preferably includes a rod  43  with a peened head  47  and large washer  44  at one end, and a slip-nut quick secure/release device  45  backing a washer at the other end. It should be understood that the connector can be any tension member with means for securing the connector or tension member at either end so that the separated panels of the ICF remain a fixed distance apart when concrete is poured into the ICF.  
         [0032]     Rebar is used to reinforce concrete poured into the ICF system  10  as is well known in the art. The rebar is installed prior to pouring the concrete between the panels  20 . The rebar includes both horizontal rebar  44  and vertical rebar  46 . The horizontal rebar is fastened to the vertical rebar. In order to avoid contact with ground water, the vertical rebar  46  should not be allowed to rest on the ground. Because of the weight of the rebar, the rebar cannot be allowed to rest on the ICF panels. Therefore, a rebar support boot  50  it provided to support most sizes of rebar. Rebar support boots  50  are shown at the bottom end of the vertical pieces of rebar in  FIG. 1 .  
         [0033]     As shown in  FIG. 4A , the rebar support boot  50  has a generally round body containing an upwardly facing cavity  54  for receiving the bottom end of the vertical piece of rebar  46 . As depicted in  FIG. 4B , the cavity  54  has a plurality of vanes  56  for engaging and securing the vertical rebar  46 , The rebar support boot  50  further includes a circular base  58  for providing stable ground support for the vertical rebar  46 . The rebar support boot further includes a downwardly pointing anchor  60  protruding from a lower portion of the rebar support. The downwardly pointing anchor serves as a locating/centering means to ensure the vertical rebar is properly located and remains properly positioned. The direction of the vanes  56  can be varied according to engineering requirements.  
         [0034]     Inner and outer wall finishes can be indirectly attached to the structural elements of the insulated concrete wall assembly using a framing stud  70  such as the one shown in  FIG. 5A  and  FIG. 5B . As would be appreciated by those of ordinary skill in the art, the framing stud is manufactured with necessary strength and ductility to enable proper penetration by and retention of a drywall screw or other fastener to secure the finishes to framing stud  70 , and thence to the structural elements, In the preferred embodiment, the framing stud  70  has a shaft  72  terminating at a point  74 . The framing stud  70  extends preferably about 4.5 inches or more from the underside of a washer-like head  78 . The washer-like head is preferably about 1.75 inches in diameter and about 0.250 inches in thickness. As shown in  FIG. 5A , the shaft  72  is radiused into the washer-like head  78  such that the diameter of the shaft is preferably about 0.5 inches at the point where the shaft meets the washer-like head. The framing stud  70  has two or more bulbous enlargements  71 ,  73  and  75 , which serve to anchor the framing stud  70  into the concrete poured into cavity  12  between panels  20  and to retain the framing stud in position in holes  27  of the panels. These bulbous enlargements at their largest diameter have a diameter of about 0.120 inches greater than the nominal shaft diameter. The first bulbous enlargement flows from point  74  to its greatest diameter at a point  75  about 0.875 inches from point  74 , thence receding to nominal shaft diameter at a point about 1.125 inches from point  74 . At about a point 1.5 inches from point  74 , a second bulbous enlargement proceeds to grow to its greatest diameter at point  73  about 2.25 inches from point  74  thence receding to a nominal shaft diameter at a point about 2.75 inches from point  74 , increasing again in diameter at about point  71  and diminishing to the nominal diameter of the shaft. The framing stud is designed to be used with the insulated concrete form system described herein. The framing stud can be inserted into preformed holes  27  prior to concrete being pumped into cavity  12 . Although preferred dimensions are described above, persons of ordinary skill in the art will of course appreciate that these may be varied without departing from the spirit of the invention.  
         [0035]     A wire-twister tool, denoted by reference numeral  80  in  FIG. 6A  and  FIG. 6B , can be used to facilitate the quick tying or twisting of wires used to secure horizontal rebar to vertical rebar used with the insulated concrete form system. As shown in  FIG. 6A , the wire-twister tool  80  has a cylindrical head  82  and a mounting shaft  84  extending from the head. In the preferred embodiment, the cylindrical head  82  is about 1.5 inches in diameter and about 1 inch in thickness. The cylindrical head  82  includes one or two pair(s) of diametrically opposed wire holes  83  which are approximately shaped like back-to-back funnels in an hourglass arrangement as shown in  FIG. 6A . The wire holes  83  are spaced about equidistantly around the cylindrical head. The wire holes  83  have funnel-shaped openings  85  on the upper and lower surfaces of the cylindrical head. Each upper funnel-shaped opening  85  converges downwardly to an intermediary hole  87  while the corresponding lower funnel-shaped opening converges upwardly to the same intermediary hole. The diameter of the intermediary hole should be sized so as to enable easy insertion of the wire ends while permitting the wire holes to properly engage the wire ends so that rotation of the tool causes the wire ends to be twisted together. The mounting shaft  84  extends from the underside of the cylindrical head  82  and has three formed flats  86  which help keep it firmly secured within a chuck of a rotary tool. The wire-twister tool  80  is preferably made of hardened, rust-resistant steel.  
         [0036]     Persons of ordinary skill in the art will understand that variations to the above embodiments may be made without departing from the spirit of this invention. The embodiments of the invention described above are intended to be exemplary only. The scope of the invention being limited solely by the scope of the appended claims.