Patent Publication Number: US-2009224134-A1

Title: Form for Casting Light Weight Composite Concrete Panels

Description:
CROSS-REFERENCE 
     This application claims priority from co-pending U.S. provisional patent application Ser. No. 60/693,823 filed Jun. 24, 2005. This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 10/565,317 which is a National Stage of PCT/US2004/023155 filed Jul. 21, 2004 which claims priority from U.S. provisional patent application Ser. No. 60/488,821 filed Jul. 21, 2003. 
    
    
     FIELD OF THE INVENTION 
     The present application is directed to forms for forming concrete, and in particular forms for casting light weight composite concrete panels. 
     BACKGROUND OF THE INVENTION 
     Composite concrete and steel frame panels have been used to construct buildings, and in particular as exterior cladding panels in industrial, commercial and residential structures. It is well known to assemble composite building panels at one location and to transport the panels to a construction site for use in fabricating structures. The use of prefabricated building components substantially reduces the labor costs at both the manufacturing and assembly processes. 
     Composite concrete panels, such as those disclosed in PCT Application Serial No. PCT/US2004/023155 to Smith, which is incorporated herein by reference, are made of metal frames partially imbedded in concrete for providing exterior wall systems. In many cases, the panels are supported on the building structure, and are not intended to bear any loading other than wind loading, however composite panels can also be used in load bearing applications. Generally, the panel includes a concrete slab having a finished exterior surface. Structural steel studs, such as C-shaped channels, are assembled into a frame and the frame is partially embedded into the concrete slab. Preferably the slab is light weight concrete, such a foam concrete, as disclosed in the above referenced Smith PCT application. Mechanical systems, insulation and wall board or other interior finish are installed on the interior of the panel. 
     Traditionally, composite concrete panels are formed by assembling an outer form comprised of wood or metal rails on a pouring pad. Interior forms can be placed with the outer from to block-out apertures for doors and windows. The outer and optional inner forms define a volume into which concrete is poured. Typically a steel frame, and reinforcing rods or mesh are embedded in the concrete. The steel can be assembled and placed within the form before the concrete is poured, or can be lowered and pressed into the concrete shortly after the concrete is poured. It is generally necessary to seal the outer and interior form members to the pouring pad. This is conventionally done with plastic sheeting or by caulking between the forms and the pouring pad to prevent the seepage of concrete underneath the forms. After at least partial curing of the concrete panel, the form members are stripped and removed. 
     The installation, sealing and removal of the forms to the pouring pad are laborious and time-consuming. Additionally, the workspace requires extensive clean-up after each panel is successively cast. 
     Accordingly, there is a need for an improved form for casting composite concrete panels. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-section through a first embodiment of a concrete form of the invention secured to a frame and retaining concrete slurry. 
         FIG. 2  is a cross-section through two adjacent composite concrete panels formed with the first embodiment form. 
         FIG. 3  is a partially cut away perspective view of a second embodiment of a concrete form of the invention. 
         FIG. 4  is a partially cut away perspective view of a third embodiment of a concrete form of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIG. 1 , a first embodiment of a concrete form  10  is shown attached to a steel frame  12  with fastener  14 . A layer of reinforcing material  16 , such as a slit and expanded steel mat, is secured to the frame. The reinforcing material and a portion of the steel frame member are partially embedded in light-weight concrete  18 , as disclosed in PCT Application Serial No. PCT/US2004/023155. The form  10  functions to retain concrete slurry  18 , space the steel frame  12  a predetermined distance D above pouring pad  20 , and seal the form to the pouring pad. 
     The form  10  comprises a vertical wall  22  having an upper portion  24  and a lower portion  26 . The upper vertical wall portion is configured to be fastened to the frame member  12  with fastener  14 . A shoulder  28  is formed between the upper and lower wall portions. The lower vertical wall portion is horizontally offset from said upper wall portion. A sealing member, namely, lip  30  extends at an obtuse angle from said lower vertical wall and is configured to form an obtuse angle with the pouring pad. The lip is preferably flexible and resilient, but with sufficient strength to support the frame. 
     The shoulder  28  functions as a marker to locate the frame at a predetermined distance D above pouring pad  20 . This distance D can vary as determined by the architect or engineer. Typically, distance D is about one inch. 
     The lip  30  functions as a lip seal to seal the form to the pouring pad. Because the flexible lip is set at an obtuse angle, as shown in  FIG. 1 , the weight of the concrete slurry  18  will force the lip downwardly into sealing engagement with pouring pad  20 . 
     The composite concrete panel is preferable manufactured by first assembling the steel frame, and placing the frame upside down on the pouring pad. Reinforcing steel is then secured to the top of the upside down frame. Form members  10  are then fastened to the outer perimeter of the steel frame and such interior apertures as may be desired. Because the frame is upside down, the forms are secured upside down, that is with the lip  30  extending in an upward and inward direction. The shoulder  26  is nested with the edge of the frame, facilitating quick and easy assembly with no need to measure distances. The form members are secured to the frame with fasteners  14 , such as screws. After the forms are in place, the assembly is flipped over, so that lips  30  engage the pouring pad  20 . Then the concrete can be poured into the interior of the form. The concrete is preferably a light weight concrete, such a foam concrete. Because the concrete is light weight the plastic forms  10  have sufficient strength to retain the concrete without need for timber or steel rails or other substantial structural elements. When the concrete has at least partially cured, the forms may be optionally stripped and removed by removing the fasteners. It is desirable however to leave the forms in place during storage and transport to protect the edges of the composite concrete panels. 
       FIG. 2  shows two concrete panels  32   a  and  32   b  fabricated using forms  10 . Adjacent panels  32   a  and  32   b  are joined together with a plurality of fasteners, e.g. screw  34 , extending between frame members  12   a  and  12   b . The lip  30  of form  10  functions to form chamfers  36   a  and  36   b  on the edge of each concrete panel. The horizontal offset between the lower  26  and upper  24  wall portions creates a desirable reveal  38  between panels  32   a  and  32   b . The reveal is preferably filled with a sealing material  40 , such as caulk or grout. 
       FIG. 3  illustrates a second embodiment  110  of the concrete form of the invention. The features of the second embodiment that correspond to like features of the first embodiment have the same reference numerals, but in the  100  series. Form  110  comprises an “L” shaped member for supporting a frame member  112  of a composite concrete panel above a pouring pad  120 . The form member  110  is attached to the frame member  112  with fasteners  114 . During assembly of the panel, the form members  110  are preferably disposed on the perimeter of a frame assembly  18  to permit the flow of concrete slurry (not shown) to partially embed the frame assembly in a concrete slab. 
     The form member  110  comprises a vertical wall  122 , and a sealing member comprising a horizontal leg  129  and seal  130 . The seal  130  sealingly engages the pouring pad  120 . Seal  130  prevents the seepage of concrete slurry under the form member  110  obviating the need to wrap the forms in plastic or the need to caulk the perimeter of the forms. The seal  130  deforms against the pouring pad  120  to retain the concrete slurry within the confines of the form. 
     The vertical wall  122  has at least one, but preferably plural markers for setting the height of frame  112  above the pouring pad  120 . The markers comprise ridges  127  disposed on an inside surface  121  for indexing the relative location of the frame member  112  with the form member  110  and pouring pad  120 . Although raised ridges  127  are disposed on the inside surface  121 , it is contemplated that other indicators may be used, such as a shoulder, recessed grooves, lines or spaced markers. Preferably, a plurality of ridges are disposed at vertically spaced intervals to facilitate selection of different heights for spacing the frame above the pouring pad and thereby the concrete cover over the frame and reinforcing materials. 
     Form members  110  are optionally removed from the panel after the concrete is cured. The horizontal leg  129  will cause the perimeter edges of the concrete panel to be slightly recessed with respect to an outer face of the concrete panel. If desired, grout or caulking can be added around the perimeter of the concrete panel to provide a flush finish with the remainder of the concrete panel. One or more ribs  137  are preferably disposed on the interior surface of leg  129  which will form corresponding grooves in the edges of the concrete panel to improve bonding of the grout or caulk to the panel. As indicated above, the form member  110  optionally may be permanently or temporally retained on the concrete panel. It is desirable to retain the form on the panel during storage and transport to protect the panel edges from damage. Referring now to  FIG. 4 , a third embodiment of the concrete form  210  of the invention is shown. The features of the third embodiment that correspond to like features of the first and second embodiments have the same reference numerals, but in the  200  series. The third embodiment is similar to the second embodiment, except that horizontal leg  229  is directed outwardly rather than inwardly. As in the second embodiment, the frame  212  is mounted to the inside surface  221  of vertical wall  222 . Concrete is poured onto the pouring pad  220  to a desired height, preferably embedding a portion of the frame assembly  212 . A seal  230  on the bottom surface of leg  229  retains the concrete within the confines of the form. However, unlike the second embodiment, when forms  210  are removed from the concrete panel, the resulting peripheral edges of the panel are flush with the remainder of the outer surface of the panel. In the third embodiment, unlike the second embodiment, it is impractical to leave the form on the panel during storage or transport because of the projecting leg  229 . 
     A single form may be used in either of the orientations shown in the second and third embodiments. Markers may be placed on both sides of the vertical wall  122 ,  222 . Thereby, the form is reversible and can be used in either orientation. 
     The form members  10 ,  110 ,  210  can be inexpensively manufactured of extruded plastic or other material having sufficient strength to hold the frame member above the pouring pad and retain concrete slurry. In the first embodiment, lip seal  30  is preferably integrally formed with vertical wall  22 . In the second and third embodiments, seal  130 ,  230  may be made separately and attached to form member  110 ,  210 . Seal  130 ,  230  preferably has a greater resiliency, i.e. is softer, than the form member  110 ,  210 . 
     While specific embodiments of the present concrete form have been shown and described, it will be appreciated by those skilled in the art that changes and modifications may be made thereto without departing from the invention in its broader aspects as defined in the claims.