Abstract:
A penetratable stiffback useful as a building form is provided and is useful as an integrated member of a forming system in conjunction with a pair of forming panels. The stiffback includes a face panel and a pair of rearwardly projecting support walls, each support wall including a lug projecting outwardly therefrom intermediate the rear margin and the rear of the face panel. The face panel includes a front face for location coplanar with a pair of adjacent forming panels to present a forming system for receiving hardenable material thereagainst, the lugs serving to reinforce the panels on either side. The system includes a connecting member for penetrating the face panel and connection to an opposing forming wall to inhibit separation of the forming walls caused by the weight of the hardenable material poured between the forming walls.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention concerns a building form and system for forming hardenable material such as concrete. More particularly, it is concerned with a method, stiffback and building form system which permits the stiffback to be used as a penetratable building form.  
           [0003]    2. Description of the Prior Art  
           [0004]    Building forms are widely used to form walls, foundations and the like of hardenable material such as concrete. Such building forms may be of different materials such as wood or foam, but these typically lack durability for repeated usage. Thus, reusable building forms are more often of metal, such as aluminum which is lightweight and durable. In constructing foundations out of such building forms, panels are typically interconnected in side-by-side relationship to comprise a forming wall, and another such forming wall is opposed thereto to receive the concrete or other flowable, hardenable and typically cementations material therebetween. To provide rigidity, especially for greater depths of material, intermediate cross-beams may be provided on the back side of the building form panels making up the forming walls.  
           [0005]    Because of the great weight of the concrete material received between the forming walls, stiffbacks are employed behind the panels to provide support and resist deflection of the panels outwardly from the material receiving area. The stiffbacks are positioned in an upright orientation behind the panels at selected intervals and may be connected to the back of the forming panels by bolting or similar fastening means. To provide further resistance to separation, tapered connecting rods penetrate through openings drilled in the panels of opposing walls and pass through the material receiving region between the opposing panels to tie the building forms of the opposing forming walls together against separation.  
           [0006]    While this system and method is useful, it is also expensive as drilling a hole through a building form renders it unsuitable for further use. Unless the hole is repaired by expensive welding due to the usually aluminum material, the entire panel must be replaced. Moreover, in addition to the panels which spanned the entire width of the wall, additional stiffback members were required to reinforce the wall. Consequently, the resulting total cost of materials of a wall including both stiffbacks and panels is greater than the panel alone.  
           [0007]    There has thus developed a need for an economical building form system which can be readily erected and used with existing ancillary equipment.  
         SUMMARY OF THE INVENTION  
         [0008]    These and other objects are largely met by the present invention. That is to say, the present invention provides a stiffback which may be used as a building form and as such, reduces the total cost of materials necessary in connection with providing a sustainable building wall. Moreover, because the stiffback is much narrower than a building panel with which it is used, the provision of a penetratable stiffback avoids the necessity of replacing an entire panel after penetration.  
           [0009]    The stiffback of the presentation is a penetratable building form presenting a relatively narrow face panel with a face for orientation toward the hardenable material and a pair of spaced apart support walls extending rearwardly from the rear surface to define a channel therebetween. The stiffback is provided with a side lug on each of the support walls for engagement or positioning in proximity to forming panels located on either side of the stiffback, and cooperates with the side panels to increase rigidity of the forming system. An attachment member is positioned at the rear margin of each wail to facilitate attachment of braces, scaffolding or other accessories to the stiffback. In preferred forms, the attachment member extends outwardly from the support walls in an L-shaped extension which defines a gutter, with a slot defined to retain fasteners in the gutter. The stiffback face panel is adapted to be provided with an opening either when formed or during use (by drilling or the like), whereby a connecting member such as a tapered rod may be inserted through the face for inhibiting movement of the stiffback caused by the weight of the hardenable material.  
           [0010]    The stiffback is preferably used in connection with standard forming panels to provide a forming system. The forming panels typically include a side rail which may abut the side lug of the stiffback, which is also connected by fasteners such as bolts, pins, or locking devices to the panels. Thus, the stiffback and panels cooperate together to provide a unitary forming system which resists shifting movement upon loading by hardenable material such as concrete into a material-receiving region between opposing forms. As noted above, the stiffback may be provided with an opening so that a connecting member may penetrate the face panel and tie opposing forming walls together. Typically, the forming walls are comprised of the stiffback and adjacent panels on one side and a corresponding stiffback and adjacent panels on the other to eliminate the need for any penetrating of the forming panels.  
           [0011]    The method of the present invention includes providing a first forming wall of interconnected panels and a stiffback located therebetween, providing a second, opposing forming wall, providing an aperture in the face panel of the stiffback, inserting a connecting member therethrough and through a second aperture in the second forming wall to interconnect the first forming wall and the second forming wall, and delivering a flowable, hardenable material into the material receiving region defined between the first and second forming walls.  
           [0012]    The stiffback and forming system hereof provide a significant improvement over the prior art, providing a stiffback which is integrated into the face of the forming wall. This results in a forming system of reduced thickness, which is especially beneficial in forming stairwells and elevator wells in buildings where the available space is restricted. By reducing the thickness or depth of the forming system used in creating the resulting walls, the forming system hereof makes installation and erection of the forms a simpler task, and may permit a wall to be poured of concrete or other hardenable material which would otherwise have been impossible or accomplished with great difficulty. Moreover, the use of a penetratable face on the stiffback avoids the necessity of penetrating a conventional panel, which may be more costly to replace, or even to repair given the reinforcements which may be used as a part thereof. The ability to penetrate the face panel of the stiffback further isolates the resulting point of weakness between the two supporting walls. The stiffback further cooperates with the ends of the supporting panels to reduce deflection under loading by the use of the side lugs which are positioned to inhibit undesired flexing of the sides of the panel and cooperate with the side rails. As a result, a highly satisfactory stiffback usable with conventional panels is provided, and the combined forming system presents advantages not present in the prior art.  
           [0013]    This and other benefits of the present invention may be appreciated by those skilled in the art with reference to the drawings and the detailed description of the preferred embodiment set forth below. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is an exploded perspective view of the stiffback and forming system of the present invention, with two superposed forming panels foreshortened and optional attachments for use with the stiffback and forming system illustrated;  
         [0015]    [0015]FIG. 2 is a fragmentary side elevational view of the stiffback in accordance with the present invention shown with an optional lifting bracket attached thereto;  
         [0016]    [0016]FIG. 3 is a fragmentary horizontal cross-sectional view of the forming system hereof, showing two opposed forming walls with a tapered connecting rod penetrating opposed stiffbacks and engaged with the rear margin of the support walls of each stiffback; and  
         [0017]    [0017]FIG. 4 is a fragmentary horizontal cross-sectional view of the stiffback located intermediate a pair of forming panels taken along line  44  of FIG. 2, showing the positioning of the rails of the forming panels to the side lugs of the stiffback. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0018]    Referring now to the drawing, a penetratable stiffback building form  10  in accordance with the present invention is shown as a part of a forming system  12  in FIG. 1. The forming system  12  includes, in addition to the stiffback  10 , a first forming panel  14  and a second forming panel  16 . The stiffback  10  is positioned intermediate the first and second forming panels and interconnected therewith to present a first forming wall  18 . A second forming wall  20  is preferably positioned opposite the first forming wall  18  to define therebetween a material receiving region  22 . A connecting member  24  may be provided to interconnect the opposed first forming wall  18  and the second forming wall  20  against relative separation.  
         [0019]    The stiffback  10  is preferably of aluminum or other durable, lightweight metal and is shown in greater detail in FIGS.  2 - 4 . The stiffback  10  and includes an elongated face panel  26  which is typically, though not necessarily vertically oriented. The face panel  26  includes a front face  28  and a rear surface  30  and a pair of side edges  32  and  34  defining a width W therebetween.  
         [0020]    First support wall  36  and second support wall  38  extend rearwardly from rear surface  30  adjacent side edges  32  and  34 , respectively. The first and second support walls preferably extend the entire longitudinal distance of the face panel  26  to provide support throughout the entire length thereof. The first support wall  36  and second support wall  38  are preferably in parallel planes and define therebetween a channel  40 . The first support wall  36  and second support wall are preferably oriented perpendicular to the face panel  26  and extend rearwardly to respective rear margins  42  and  44  for a depth D which is greater than the width W of the face panel  26  to provide adequate structural stiffness and support.  
         [0021]    Each of the first and second support walls is provided with a lug  46 ,  48  which projects laterally from the respective support wall  36 ,  38  and preferably extends the entire length thereof. The lugs  46 ,  48  are positioned rearwardly of the rear surface of the face panel  26  and forwardly of an attachment member  50 ,  52  proximate the rear margins  42 ,  44 . A plurality of connection holes  54  are spaced along the length of each of the support walls  36 ,  38 , so that a connection hole  54  of the first support wall  36  is opposite and in registry with the connection hole  54  of the second support wall  38 . The connection holes  54  are positioned on the support walls forwardly of the lugs and rearwardly of the rear surface  30 .  
         [0022]    The attachment members  50  and  52  are L-shaped and preferably extend laterally from the support walls outside the channel  40  the entire length of the stiffback  10 . Each attachment member  50 ,  52  includes a leg  56  extending perpendicular to the support wall and a foot  58  extending rearwardly and parallel to its respective support wall to define a gutter  60  therebetween. The gutter  60  is sized to receive a bolt head, nut or the like therein, which in turn is restrained from further rearward movement by convergent rails  62 ,  64  oriented parallel to the leg and defining a slot  66  therebetween. The slot  66  permits vertical movement of a bolt shank therealong as illustrated in FIG. 1, but the rails  62  and  64  of each attachment member restrain the bolt head or nut in the gutter  60  from rearward movement. Each of the rails  62 ,  64  of the attachment members preferably extend the length of the stiffback  10  and are coplanar with one another at the rear margin  42 ,  44  of the respective support wall.  
         [0023]    The attachment members  50 ,  52  are thus configured for connection with accessories such as an expandable wall brace  68  or a horizontal waler  70 . In addition, accessories such as a scaffold bracket  72 , a lifting bracket  74  with clevis  76  and a gang leveler  78  may be secured to the support walls  36  and  38  by bolts  80  or other fasteners passing through connection holes  54 .  
         [0024]    Forming panels  42  and  44  each include respective face plates  82  and  84 , and side rails  86  which are of a depth equivalent to the distance between face panel  26  and lugs  46 ,  48 . The side rails  86  are provided with a plurality of holes  88  which are spaced corresponding to the spacing of the connection holes  54  of the support walls. The forming panels  14  and  16  also include upper rails  90  and lower rails  92  for connection by bolts  80  to the rails on other such panels  94  in superposed relationship to achieve the desired height for the wall to be formed. It may be appreciated that the forming panels  42  and  44  may include, in addition, corner gussets, rigid box braces extending either horizontally or vertically behind the face sheet of the panel for added support and rigidity, and attachment hardware base plates and pins as is known in the art.  
         [0025]    The connection member  24  is provided to interconnect the first and second forming walls. The connection member  24  includes a tapered tie rod  96 , an engagement bracket  98  and a threaded wing nut  100 . The face panel  26  of the stiffback  10  in each of the first and second forming walls  18 ,  20  is provided with an aperture  102  at the desired height during installation. As shown in FIG. 4, the tapered tie rod  96  spans the material receiving region between the face of each of the opposed stiffbacks  10  of the respective first forming wall and second forming wall, with the engagement bracket  90  abutting the attachment members of each stiffback  10 . The aperture  102  is preferably sized corresponding to the diameter of the tapered tie rod  96  to inhibit passage of concrete or other hardenable material therethrough. The aperture  102  is provided in the face panel between the support walls  36  and  38  as shown in FIG. 4 for maximizing strength of the stiffback  10 , and the number of apertures  102  and their height along the length of the stiffback will depend on the height of the wall to be formed and the width of the forming system.  
         [0026]    In use, the forming system  14  is first assembled by positioning the stiffback  10  intermediate the first and second forming panels  16  and  18 , and such other panels  94  positioned therebeneath as required to provide a first forming wall  18  of desired height. The lower rails  92  are connected by bolts  80  and nuts  110  or pin-fastened using locking or conventional pins to the upper rails  90  of the panel  94  therebeneath. The side rails  86  are brought into engagement with the support walls  36  and  38  of the stiffback, with the connection holes  54  in registry with holes  88  on the side rails  86 . Preferably, the connection holes  54  are positioned so that the margins  104  of the side rails  86  lie in abutment with the lugs  46  and  48  when bolts  80  are inserted through holes  54  and  88  and secured by nuts  106 . The side rails  86  thus engage lugs  46  and  48  closely adjacent to support walls  36  and  38  to resist imparting a large moment to the lugs by the forming panels through the side rails, and thereby maximizing rigidity of the combined forming system  12 . Additional forming panels and stiffbacks are alternated until the entire first forming wall is completed.  
         [0027]    Once the first forming wall  18  is assembled, preferably including lifting bracket  74 , the wall  18  is lifted into position, and a second forming wall  18  is positioned opposite first forming wall  18  preferably with the stiffbacks  10  in direct opposition as shown in FIG. 3, each forming wall  18 ,  20  being leveled as appropriate. To inhibit relative displacement between the forming walls due to the weight of the hardenable material deposited therebetween, apertures  102  are created by drilling or the like in the face panel  26  of each opposed stiffback  10 . Preferably, the apertures are located vertically intermediate the junction between upper rails  90  and lower rails  92  to avoid a concentration of stress.  
         [0028]    Connection member  24  secures the stiffbacks and thus the first and second walls against displacement by insertion of the tapered tie rod  96  through the apertures  102 , placing the engagement brackets  98  over the ends of the rod  96 , and tightening the wing nut  100  to bring the engagement brackets into engagement with the rear margins  42  and  44 . Expandable wall brace  68  may then be secured to the attachment members  50  and  52  by suitable nuts and bolts  108  as shown in FIGS. 1 and 3, where the wall brace  68  is visible below the engagement bracket  98 . With the first and second forming walls so positioned, hardenable material such as concrete is poured into the material receiving region  22  which accumulates to the desired height of the wall. The hardenable material may well reach a height greater than aperture  102  and surround tapered tie rod  96 . However, the tapering of the tie rod  96  permits its withdrawal through the aperture  102  after the concrete or other material has cured to hardness, thereby permitting removal and reuse of the stiffbacks  10  and forming panels. After use, the stiffbacks  10  may be discarded or the apertures drilled therein repaired by welding plates or the like over the apertures.  
         [0029]    The present invention thus provides an economical forming system which can be used in forming concrete walls where areas of only limited access are provided, such as elevator shafts and stairwells. Although preferred forms of the invention have been described above, it is to be recognized that such disclosure is by way of illustration only, and should not be utilized in a limiting sense in interpreting the scope of the present invention. Obvious modifications to the exemplary embodiments, as hereinabove set forth, could be readily made by those skilled in the art without departing from the spirit of the present invention.  
         [0030]    The inventor hereby states his intent to rely on the Doctrine of Equivalents to determine and assess the reasonably fair scope of his invention as pertains to any apparatus not materially departing from but outside the literal scope of the invention as set out in the following claims.