Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Not Applicable 
       STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENT 
       [0002]    Not Applicable 
       BACKGROUND 
       [0003]    1. Technical Field 
         [0004]    The present invention relates generally to the art of concrete construction, and more particularly to devices for facilitating the placement of slip dowel rods within adjacent concrete slabs. 
         [0005]    2. Background 
         [0006]    In the art of concrete construction, it is commonplace to form “cold joints” between two or more poured concrete slabs. Such cold joints frequently become uneven or buckled due to normal thermal expansion and contraction of the concrete and/or compaction of the underlying soil caused by inadequate substrate preparation prior to pouring of the concrete. As a means of preventing buckling or angular displacement of such cold joints, it is common practice to insert smooth steel dowel rods generally known as “slip dowels” within the edge portions of adjoining concrete slaps in such a manner that the concrete slabs may slide freely along one or more of the slip dowels, thereby permitting linear expansion and contraction of the slabs while at the same time maintaining the slabs in a common plane and thus preventing undesirable buckling or unevenness of the cold joint. 
         [0007]    In order to function effectively, slip dowels must be accurately positioned parallel within the adjoining concrete slabs. The non-parallel positioning of the dowels may prevent the desired slippage of the dowels and may defeat the purpose of the “slip dowel” application. Additionally, the individual dowels must be placed within one or both of the slabs in such a manner as to permit continual slippage or movement of the dowels within the cured concrete slab(s). 
         [0008]    In the prior art, two methods of installing smooth “slip dowels” have become popular. According to the first method, a first concrete pour is made within a pre-existing form. After the first pour has cured, an edge of the form (usually a wooden stud) is stripped away. A series of holes are then drilled parallel into the first pour along the exposed edge from which the form has been removed. The depth and diameter of the individual holes varies depending on the application and the relative size of the concrete slabs to be supported. As a general rule, however, such holes are at least 12 inches deep and typically have a diameter of approximately five-eighths of an inch. 
         [0009]    After the parallel aligned series of holes has been drilled into the first pour, smooth dowel rods are advanced into each such hole such that one end of each dowel rod is positioned within the first pour and the remainder of each dowel rod extends into a neighboring area where a second slab of concrete is to be poured. Thereafter, concrete is poured into such neighboring area and is permitted to set with the parallel aligned dowels extending thereinto. After the second pour has set, the slip dowels will be held firmly within the second slab but will be permitted to slide longitudinally within the drilled holes of the first slab thereby accommodating longitudinal expansion and contraction of the two slabs while at the same time preventing buckling or angular movement therebetween. 
         [0010]    Although the above-described “drilling method” of placing slip dowels is effective, it will be appreciated that such method is extremely labor intensive. Along these lines, it generally takes approximately ten minutes to drill a five-eighths inch diameter by twelve inch long hole into the first pour. Furthermore, the drilling equipment, bits, accessories, and associated set up time tends to be very expensive. Moreover, the laborers who drill the holes and place the slip dowels must be adequately trained to ensure that the dowels are arranged perpendicular to the joint. 
         [0011]    Another prior art method of slip dowel installation is shown in  FIGS. 1-3 , and includes the use of a base member  10  and a tubular dowel receiving sheath  12  which is connectable to the base member  10 . The base member  10  includes an attachment plate  14  and an axial extension member  16  extending from the attachment plate  14 . The base member  10  is connected to the inner face  18  of the form  20 , such that the extension member  16  extends from the form  20  into the area where the concrete  22  is to be poured. Before the concrete  22  is poured, the sheath  12  is slid over the extension member  16  to maintain the sheath  12  in proper position during pouring and curing of the concrete  22 .  FIG. 2  shows the sheath  12  completely advanced over the extension member  16  before the concrete  22  is poured, while  FIG. 3  shows the sheath  12  on the extension member  16  after the concrete  22  is poured. After the concrete  22  cures, the form  20  is removed, along with the base member  10 , while the sheath  12  remains embedded within the cured concrete slab  22 . 
         [0012]    Though the use of the prior art placement device shown in  FIGS. 1-3  presents advantages over the previously described placement methods, these methods and devices also possess certain deficiencies which detract from their overall utility. In particular, the particular mounting configuration of the base member  10  to the concrete form  20  (i.e., the base member  10  nailed to the inner surface  18  of the concrete form  20 ) may be associated with several drawbacks. One drawback is that the nail securing the base member  10  to the concrete form  20  may not always provide enough rigidity, which may lead to the base member  10  bending or breaking, especially if the base member  10  is inadvertently stepped on or loaded with the weight of a rebar mat. Another drawback is that the mounting configuration of the base member  10  shown in  FIGS. 1-3  may make it difficult to remove the form  20  because the base member  10  may be adhered to the concrete  22 , which may lead to cracked or broken base plates  10 . 
         [0013]    Therefore, in view of the foregoing, there is a need in the art for an improved slip dowel system that facilitates placement of slip dowel rods within adjacent concrete slabs, while at the same time mitigating the deficiencies noted above. 
       BRIEF SUMMARY 
       [0014]    There is provided an improved concrete dowel placement apparatus having a base member configured to attach to the concrete form in a manner which mitigates several of the deficiencies noted above. More specifically, the base member includes a base plate that is disposable on the outer surface of the concrete form, and a base extension member that extends through an aperture located within the concrete form. In this regard, the base member is supported by the concrete form, and is therefore generally configured to withstand higher loads than the conventional prior art designs. Furthermore, the particular attachment configuration spaces the base plate from the concrete slab, which generally prevents the base member from becoming embedded within or adhered to the concrete. As such, removal of the form from the cured concrete tends to be much easier than removal of conventional prior art systems. In addition, the base member is less likely to crack or break during removal, which reduces the overall cost, as fewer base members may need to be replaced. 
         [0015]    According to one embodiment, the concrete dowel placement apparatus is configured for use with a form member having a first face, an opposing second face, and an aperture extending from the first face to the second face. The concrete dowel placement apparatus includes a base member comprising a base plate defining a proximal face and an opposing distal face, and an extension member having a first extension member end portion and an opposing second extension member end portion. The first extension member end portion is coupled to the proximal face of the base plate. The base member is attachable to the form member with the extension member extending through the aperture and the proximal face of the base plate facing the first face of the form member. The concrete dowel placement apparatus further includes a dowel receiving sheath having a first sheath end portion and an opposing second sheath end portion and a hollow interior compartment extending longitudinally therein. The first sheath end portion is slidably extensible over the second extension member end portion such that the second extension member end portion resides within the interior compartment. 
         [0016]    It is contemplated that the base member extension member may be sized to frictionally engage with the form upon insertion through the aperture. Such frictional forces may secure the base member to the concrete form. Alternatively, mechanical fasteners, such as a nail, may be used to secure the base member to the form. 
         [0017]    The present invention will be best understood by reference to the following detailed description when read in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    These and other features and advantages of the various embodiments disclosed herein will be better understood with respect to the following description and drawings, in which like numbers refer to like parts throughout, and in which: 
           [0019]      FIG. 1  is an upper perspective view of a prior art concrete dowel placement apparatus including a base member and a dowel receiving sheath, wherein the base member is connected to the inner face of a concrete form; 
           [0020]      FIG. 2  is a side sectional view of the prior art concrete dowel placement apparatus before concrete is poured; 
           [0021]      FIG. 3  is a side sectional view of the prior art concrete dowel placement apparatus after the concrete has been poured; 
           [0022]      FIG. 4  is an upper perspective view of one embodiment of a concrete dowel placement apparatus having a base member having an extension member extendible through an aperture formed within the concrete form and a base plate disposable adjacent the outer surface of the concrete form, and a dowel receiving sheath; 
           [0023]      FIG. 5  is a side sectional view of the concrete dowel placement apparatus depicted in  FIG. 4  before concrete has been poured; 
           [0024]      FIG. 6  is a side sectional view of the concrete dowel placement apparatus depicted in  FIG. 4  after concrete has been poured; 
           [0025]      FIG. 7  is a side sectional view of the concrete dowel placement apparatus with the concrete form and base member removed from the concrete slab and the dowel receiving sheath; and 
           [0026]      FIG. 8  is a side sectional view of two adjacent slabs of concrete with a dowel extending from one slab into the sheath disposed within the adjacent slab. 
       
    
    
       [0027]    Common reference numerals are used throughout the drawings and the detailed description to indicate the same elements. 
       DETAILED DESCRIPTION 
       [0028]    The detailed description set forth below in connection with the appended drawings is intended as a description of the presently preferred embodiment of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. It is understood that the use of relational terms such as first and second, top and bottom, and the like are used solely to distinguish one from another entity without necessarily requiring or implying any actual such relationship or order between such entities. 
         [0029]    Referring now to the drawings, wherein the showings are for purposes of illustrating preferred embodiments of the present invention only, and are not for purposes of limiting the same, there is shown a concrete dowel placement apparatus  30  including a base member  32  and an elongate, tubular dowel receiving sheath  34  which is engageable with the base member  32 . The base member  32  includes a base plate  36  and an extension member  38  connected to and extending from the base plate  36 . It is contemplated that the base member  32  is used with a concrete form  40  for forming poured concrete  42 . Along these lines, the concrete form  40  includes one or more apertures  44  extending through the form  40 , and defines a pour area where the concrete  42  is poured. The base member  32  is configured to engage with the form  40  such that the extension member  38  extends through an aperture  44  and the base plate  36  is disposed against the outer surface  46  of the form  40  (i.e, the surface outside of the pour area). 
         [0030]    By positioning the base plate  36  outside of the pour area and the extension member  38  through the form  40 , the base member  32  achieves several advantages relative to prior art dowel placement apparatuses. In particular, the connection between the base member  32  and the form  40  is enhanced by advancing the extension member  38  through the form  40 . The nail used to fasten conventional base members to the form  40  may not always provide enough rigidity, which may lead to bending of the base plate  36  or complete fracturing of the base plate  36  if an excessive load is applied, as may occur if the base member  32  is stepped on or loaded with the weight of a rebar mat. Furthermore, due to the configuration and attachment of conventional base members to the inner surface  48  of the form  40 , removal of the form  40  from the cured concrete  42  tends to be difficult. In particular, the base plate  36  tends to stick to the concrete  42 , creating broken base plates  36 , or a base plate  36  that remains with the concrete  42 . Conversely, the base member  32  shown in the figures is attached to the form  40  such that the base plate  36  is spaced from the poured concrete  42 . As such, the base plate  36  does not stick to the concrete  42  when the concrete  44  is removed. In this regard, according to one implementation, no portion of the base member  32  contacts the concrete  42  when the concrete  42  is poured. Furthermore, the strength of the base member  32  is enhanced by the engagement between the extension member  38  and the form  40 . Therefore, breaking or bending of the base member  32  is mitigated in the event someone inadvertently steps on the base member  32 , or if the base member  32  is loaded with a rebar mat. 
         [0031]    The concrete form  40  may define a first face  46 , an opposing second face  48  and an aperture  44  extending through the form  40  from the first face to the second face  48 . The form  40  defines a form width “W” extending from the first face  46  to the second face  48 . In this regard, the aperture  44  extends through the width W of the form  40 . The form  40  may be fabricated from wood, plastic, or other materials known by those skilled in the art. 
         [0032]    The form  40  defines a pour area into which the concrete  42  is poured and allowed to cure. In this regard, the concrete form  40  defines a boundary which corresponds to the shape of the desired concrete structure. After the concrete  42  is poured and cured, the form  40  is removed from the cured concrete  42 . 
         [0033]    The base member  32  is configured to be easily connected to the concrete form  40  in a manner which mitigates damage to base member  32  and also facilitates removal of the form  40  and base member  32  from the cured concrete slab. According to one aspect of the present invention, the unique attachment of the base member  32  to the concrete form  40  substantially isolates the base member  32  from the concrete  42  to reduce the likelihood of the base member  32  becoming partially implanted or embedded in the cured concrete  42 . 
         [0034]    The base member  32  includes a base plate  36  having a proximal face  52 , an opposing distal face  54 , and a sidewall  56  extending between the proximal face  52  and the distal face  54 . The sidewall  56  may be angled such that the periphery of the proximal face  52  is circumscribed by the periphery of the distal face  54 , with the sidewall  56  extending between the proximal face periphery to the distal face periphery. When the base member  32  is connected to the form  40 , the proximal face  52  of the base plate  36  faces the first face  46  of the form  40 , preferably in abutting relation with the first face  46 . The sidewall  56  of the base plate  36  may be angled to provide a space between the base plate  36  and the form  40  to allow a user to grip the base member  32  to easily remove the base member  32  from the form  40 . 
         [0035]    The base member  32  additionally includes an extension member  38  coupled to the base plate  36 . The extension member  38  includes a first end portion  58  and an opposing second end portion  60 , with the first end portion  58  of the extension member  38  being connected to the proximal face  52  of the base plate  36  and the second end portion  60  terminating to define a distal tip  62 . The extension member  38  defines an extension member length as the distance along the extension member  38  between the proximal face  52  of the base plate  36  to the distal tip  62 . 
         [0036]    According to one embodiment, the extension member  38  is integrally formed with the base plate  36  and is generally perpendicular to the base plate  36 . However, it is understood that other embodiments may include an extension member  38  that is detachable from the base plate  36  to allow for replacement of the extension member  38 , for instance, to replace the extension member  38  should the extension member  38  inadvertently break. The extension member  38  is coaxially disposed relative to the base plate  36 , which extends radially from the extension member  38 , although in other embodiments, the extension member  38  may be offset from the axis defined by the base plate  36 . Furthermore, other embodiments may include an extension member  38  that is non-perpendicular to the base plate  36 . In general, the angle between the base plate  36  and the extension member  38  corresponds to the angle between the axis defined by the form aperture  44  and the first and second faces  46 ,  48  of the form  40  to allow the extension member  38  to pass through the aperture  44  when the base plate  36  is disposed adjacent the first face  46  of the form  40 . 
         [0037]    The extension member  38  is preferably sized and configured to be complimentary to the size of the aperture  44  so as to effectuate frictional engagement between the extension member  38  and the form  40  when the extension member  38  is inserted into the aperture  44 . In the particular embodiment shown in the figures, the extension member  38  defines a substantially cylindrical shape, and includes an outer sleeve and an inner sleeve with reinforcement walls extending between the outer sleeve and the inner sleeve. Although, those skilled in the art will appreciate that the extension member  38  may define other shapes and configurations without departing from the spirit and scope of the present invention. 
         [0038]    The base member  32  is additionally configured to operative in cooperation with a sheath  34  defining an embedded end portion  64  and an opposing engagement end portion  66 . The sheath  34  defines a shape that is generally complimentary to the shape of the extension member  38 . In this regard, the sheath  34  shown in the figures is substantially cylindrical. The sheath  34  defines an engagement face  68  that abuts the second face  48  of the form  40 , as explained in more detail below. An inner cavity  70  extends into the sheath  34  from the engagement face  68  toward the embedded end portion  64 . The sheath  34  is further configured to slidably engage with the extension member  38 . In this regard, the inner cavity  70  is configured to insertably receive the second end portion  60  of the extension member  38 . 
         [0039]    Although the foregoing describes a sheath  34  that is configured to slidably receive the extension member  38 , it is contemplated that the slidable engagement between the sheath  34  and the extension member  38  may be achieved by creating an internal cavity within the extension member  38  sized to receive the sheath  34 . In this regard, the sheath  34  would be insertable within the extension member  38  to achieve the slidable engagement between the extension member  38  and the sheath  34 . 
         [0040]    The outer surface of the sheath  34  may be textured to mitigate removal of the sheath  34  from the cured concrete. As shown in the figures, the outer surface of the sheath  34  includes threads to enhance the engagement of the sheath  34  within the concrete  42 . 
         [0041]    With the basic structural features of the apparatus  10  described above, the following discussion will focus on usage of the apparatus  10 . The concrete form  40  is arranged to define the pour area where the concrete  42  is to be poured. The second, inner face  48  of the form  40  faces toward the pour area and the first, outer face  46  of the form  40  faces away from the pour area. The base member  32  is connected to the concrete form  40  by inserting the extension member  38  through the aperture  44  formed within the form  40  until the proximal face  52  of the base member  32  is brought into contact with the first, outer face  46  of the form  40 . In this regard, the base plate  36  is disposed outside of the pour area, and a portion of the extension member  38  extends through the aperture  44  into the pour area. Preferably, the extension member  38  is sized to frictionally engage with the form  40  upon insertion through the aperture  44  so as to maintain the base member  32  in place relative to the form  40 . It is also understood that mechanical fasteners, such as nails, may be used to secure the base member  32  to the form  40 . For instance, nails may be inserted through the base plate  36  to connect the base plate  36  to the form  40 . 
         [0042]    The sheath  34  is then slidably engaged with the extension member  38  to properly position the sheath  34  within the pour area. In particular, the open, engagement end  66  of the sheath  34  is advanced over the distal tip  62  and second end portion  60  of the extension member  38  until the engagement face  68  is disposed adjacent the second face  48  of the form  40 , preferably in contact therewith. The sheath  34  and extension member  38  are both configured to enable the sheath  34  to remain engaged with the extension member  38 , with the sheath  34  suspended from the ground. Furthermore, when the sheath  34  is engaged with the extension member  38 , the sheath  34  preferably covers the extension member  38 , such that when the concrete  42  is poured into the pour area, the sheath shields the extension member  38  from the concrete  42 . 
         [0043]    With the sheath  34  engaged with the extension member  38 , the concrete  42  is poured into the pour area. When the concrete  42  is poured, the sheath  34  becomes embedded in the concrete  42 , while the base plate  36  and extension member  38  remain spaced from the concrete  42 . Along these lines, the concrete form  40  and the sheath  34  collectively shield the base member  32  from the concrete  42 . 
         [0044]    The poured concrete  42  is given time to cure. After the concrete  42  cures, the base member  32  is removed from the form  40 . Given that the base member  32  is shielded from the concrete  42 , the base member  32  is easily removed from the form  40 , i.e., the base member  32  is not partially embedded within or adhered to the cured concrete  42 . Furthermore, the angled peripheral surface may provide a finger grip for pulling the base member  32  from the form  40 . If mechanical fasteners are used to secure the base member  32  to the form  40 , the mechanical fasteners are removed to facilitate removal of the base member  32  from the form  40 . With the base member  32  removed, the form  40  is then removed from the cured concrete  42 . 
         [0045]    Although the foregoing describes the step of removing the base member  32  from the concrete form  40  prior to removing the concrete form  40  from the cured concrete  42 , those skilled in the art will appreciate that the concrete form  40  may be removed from the concrete  42  before the base member  32  is removed from the concrete form  40 . 
         [0046]    The particular configuration of the base member  32  provides several advantages over conventional prior art devices. In particular, the configuration of the base member  32  which allows for the unique attachment of the base member  32  to the outer surface  46  of the concrete form  40  advantageously places the base member  32  away from the concrete  42 . In this regard, the form  40  and the sheath  34  shield the base member  32  such that the base member  32  does not become stuck in the cured concrete  42 . Consequently, the base member  32  may be easily removed without breaking after the concrete  42  is cured. As such, fewer base members  32  will break and the lifecycle of each base member  32  will increase, i.e., the base members  32  may be used for longer periods of time. 
         [0047]    Furthermore, the configuration of the base member  32  may increase the amount of load that may be supported by the base member  32 . When the base member  32  is engaged with the concrete form  40 , the extension member  38  is advanced through the aperture  44  located within the form  40 . As such, the concrete form  40  supports the extension member  38 , and any load applied thereto. For instance, if a rebar mat is placed upon the extension member  38 , the load of the rebar mat applied to the extension member  38  is supported by the concrete form  40 . Furthermore, if a worker inadvertently steps on the extension member  38 , the inadvertent load applied to the extension member  38  is supported by the form  40 , which reduces the likelihood the extension member  38  would break. 
         [0048]    Referring now specifically to  FIG. 8 , after the concrete slab has cured and the form  10  is removed, a second, adjacent concrete slab  80  is poured with a dowel  82  inserted within the sheath  34  and extending into the second adjacent concrete slab  80 . After the second concrete slab  80  has cured, the dowel remains partially within the concrete slab  80  and partially within the sheath  34  to allow the slabs  80 ,  42  to move relative to each other, while at the same time remaining in the same plane. 
         [0049]    The particulars shown herein are by way of example and for purposes of illustrative discussion of the embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the present invention. In this regard, no attempt is made to show structural details of the present invention in more detail than is necessary for the fundamental understanding of the present invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the present invention may be embodied in practice.

Technology Category: 0