Patent Publication Number: US-2004040247-A1

Title: Rebar attachment device

Description:
FIELD OF THE INVENTION  
       [0001] The present invention relates generally to connective systems. More specifically, the invention relates to a system that supportively positions vertical reinforcement bars by connecting them to horizontal reinforcement bars.  
       BACKGROUND OF THE INVENTION  
       [0002] Reinforcing bar (rebar) is typically placed in concrete structures, such as concrete foundation blocks and solid concrete stem walls, during construction to provide tensile strength and rigidity. This is accomplished by suspending rebar in coplanar grid-like patterns within forms before filling the forms with cement. In order to maintain a stationary rebar configuration as concrete is poured, it is common practice to manually bind reinforcing bars together with wire ties where they intersect. This means of connecting rebar, while functionally adequate, is costly due to the time consuming nature of tying each intersection of rebar by band.  
       [0003] A footing typically incorporates pairs of horizontal reinforcing bars, lying parallel to the form walls, to which additional cross-pieces of rebar are connected. It is common practice for the bases of vertical reinforcing bars to be anchored by lashing them with wire ties at the intersections of the parallel reinforcing bars with their connecting crosspieces. The vertical bars have a high center of gravity relative to the joinder point with a horizontal bar. Thus, any joinder mechanism for this purpose must be sturdy, tight and secure. It is critical that the proper vertical orientation of the reinforcing bars be maintained as cement is poured into the forms. Fastening overlapping rebar with wire lashing in coplanar grids is undesirable because it is time consuming, and labor and skill intensive.  
       [0004] In recent years, preformed rebar connectors have been used to hold overlapping reinforcing bars in coplanar configurations. For example, see U.S. Pat. No. 5,371,991 and No. 5,878,546. However, these patents fail to provide satisfactory way of securing vertical rebar supports for a vertical cement wall.  
       SUMMARY OF THE INVENTION  
       [0005] The invention provides a connective system, and related methods for supportively positioning a rebar configuration for a vertical cement wall. A vertical piece of rebar is connected to at least one horizontal reinforcing bar via a preformed junction device. The preformed junction device may include multiple tube-like clamps rigidly connected to each other in a mutually perpendicular orientation. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0006]FIG. 1 is a perspective view of a rebar system for a vertical wall.  
     [0007]FIG. 2 is a perspective view of a preformed junction device, including open-ended clamps for supporting rebar.  
     [0008]FIG. 3 is a side view of the junction device shown in FIG. 2.  
     [0009]FIG. 4 is a perspective view of another rebar support system of the present invention.  
     [0010]FIG. 5 is a perspective view of a preformed junction device used in the support system shown in FIG. 4.  
     [0011]FIG. 6 is a cross-sectional view of a rebar system anchored in solid rock.  
     [0012]FIGS. 7 and 8 show alternative uses of coupling devices in which only two of three clamp members are used. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
     [0013] The present invention enables supportive placement of a vertical reinforcing bar within a footing or other upright construct. An embodiment of the invention is shown in FIG. 1. Reinforcement bar configuration  20  used preformed junction devices  22  to secure pieces of rebar in the desired configuration. As shown in FIG. 1, junction device  22  fixedly connects vertical reinforcing bar  24  with two horizontal reinforcing bars,  26  and  28 , in a mutually perpendicular relationship, thereby providing stationary support for vertical reinforcing bar  24  within a footing form  30  prior to its being filled with cement.  
     [0014] Junction device  22 , is shown in FIG. 2, including three elongate members  32 ,  34 , and  36 , each member having a C-shaped cross-section and forming an open-ended, tube-like clamp. Additional embodiments of the invention may also adopt alternatively configured cross-sections to accommodate square- or otherwise-shaped bars in place of traditional, substantially circular, reinforcing bars. The longitudinal axes associated with clamps  32 ,  34 , and  36  are mutually perpendicular. The crossing region of junction device  22  may be referred to as an “intersection”. A receiving aperture  38  extends along the full length of each clamp  32 ,  34 , and  36 , running parallel to its respective longitudinal axis, which is responsible for each clamp&#39;s C-shaped cross-section.  
     [0015]FIG. 3 shows a side view of the junction device shown in FIG. 2. Each of the elongate members is situated against a corner structure formed by the other two elongate members. For example, in FIG. 3 clamp  34  is situated in corner  44  formed by clamps  32  and  36 . Opening  38  of clamp  34  is situated so that a plane AA bisecting clamp  34  through the middle of opening  38  goes through corner  44  formed by clamps  32  and  36 . Each of the other clamps has a similar orientation relative to the other clamps. This orients the clamp openings so that they are most accessible for engaging pieces of rebar.  
     [0016] The clamps may be joined with any suitable bonding material such as glue, adhesive, putty, or mechanical attachment mechanisms such as screws, tacks, rivets, etc.  
     [0017] As shown in FIG. 3, the arc defined by each aperture  38  is less than 180 degrees. The width of each aperture  38  is less than the inner diameter of each clamp  32 ,  34 , and  36 . Receiving aperture  38  of clamp  34  has a beveled edge or lip configured for easy “snap-on” engagement of a piece of rebar. Each edge  45  of aperture  38  has an inner corner  46  that is obtuse.  
     [0018]FIG. 4 shows another rebar support configuration  50 . Rebar intersection  52  is secured by junction device  54 . Junction device  54  connects horizontal rebar piece  56  to vertical rebar piece  58  and a second horizontal rebar piece  60  so that the rebar pieces are mutually perpendicular to each other. Rebar piece  60  has one end fit into a socket portion of junction device  54 . The opposite end of rebar piece  60  extends over and rests on top of horizontal rebar piece  62  near adjacent intersection  64 . Rebar intersection  64  is supported by junction device  66 . Junction device  66  connects horizontal rebar piece  62  with vertical rebar piece  68  and a second horizontal rebar piece  70  which spans to the next rebar intersection analogous to horizontal rebar piece  60 . Rebar intersection  74  is supported by junction device  76  which connects horizontal rebar piece  72  with vertical rebar piece  78  and a second horizontal rebar piece  80  that spans intersections  74  and  82 . Intersection  82  is analogously configured. The rebar support system shown in FIG. 4 differs from the one shown in FIG. 1 in that separate horizontal rebar sections span adjacent rebar intersections. Whereas, in FIG. 1 a single horizontal rebar structure spans all or at least more than two of the rebar intersections.  
     [0019]FIG. 5 shows a close up perspective view of junction device  54 . Three elongate tube members  90 ,  92 , and  94  are bonded rigidly together in a mutually perpendicular orientation. Tube members  90  and  92  have a pass-through configuration for connecting to an intermediate rebar section. In contrast, tube member  94  has a socket configuration which is open at one end and closed at the opposite end against the dorsal side of tube member  90 . Each of tube members  90 ,  92 , and  94  have an opening  96  similar to the openings previously described and shown in FIGS. 2 and 3.  
     [0020]FIG. 6 shows rebar configuration  100  that is used to anchor a concrete foundation to solid rock  102 . Forms  104  are supported by braces  106  for holding concrete when it is poured over rock  102 . Holes are drilled in rock  102 . Vertical rebar pieces  112  are mounted in the rock holes. Vertical rebar pieces  112  are connected to horizontal rebar pieces  114  and  116  by coupling devices  118  which are the same or similar to coupler  22  in FIG. 2. Another coupling device  124  is used to connect horizontal rebar pieces  114  and  126  with vertical rebar piece  128 , in mutually perpendicular orientations.  
     [0021]FIG. 7 shows coupling mechanism  130  in which coupling device  131  is used to connect horizontal rebar pieces  132  and  134 , for example, to support a concrete floor. In this application, clamps  136   a  and  136   b  are used while clamp  136   c  remains open and unused. In FIG. 8, coupling system  140  is used, for example, to secure rebar in a vertical wall. Coupling device  141  connects horizontal rebar piece  142  to vertical rebar piece  144  in a perpendicular orientation. Clamp members  146   a  and  146   b  are used while clamp member  146   c  remains open and unused. FIGS. 7 and 8 illustrate that coupling devices of the present invention, for example, such as the coupling device  22  in FIG. 2, may be used in a variety of different rebar configurations in which all or less than all of the clamp members are used.  
     [0022] In preferred embodiments of the invention, the inner diameter of each tube-like clamp is sized to tightly encompass a rebar shaft. Junction devices may be formed so that each clamp portion engages the same size of rebar, such as standard 12 mm diameter rod. Alternatively, junction devices may incorporate differently sized clamps in order to connect rebar of different sizes. Each tube-like clamp is preferably about two inches in length, although the clamp length of alternate embodiments may be increased or decreased as needed to provide optimal clamping performance as the diameter and length of rebar, as well as the context of each individual application, varies.  
     [0023] Each of the tube-like clamps should be formed of a resilient material. This characteristic allows the receiving edges of the aperture to bend and flex around the shaft of the rebar as it is pressed into the clamp and to also constrict around the shaft after it is engaged. In preferred embodiments of the invention, a molded plastic such as PVC, polystyrene, polyethylene or flexible metal material may be used.  
     [0024] While the present invention has been particularly shown and described with reference to the foregoing preferred embodiments, those skilled in the art will understand that many variations may be made therein without departing from the spirit and scope of the invention as defined in the following claims. The description of the invention should be understood to include all novel and non-obvious combinations of elements described herein, and claims may be presented in this or a later application to any novel and non-obvious combination of these elements. Where the claims recite “a” or “a first” element or the equivalent thereof, such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements.