Abstract:
A spacer for positioning and locking spaced reinforcing cages into a combined integral unit for reinforcing large concrete structures is disclosed that is readily snapped into place even with narrow lattice cages.

Description:
CROSS-REFERENCED TO RELATED APPLICATIONS 
     Not applicable 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable 
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     The present invention relates generally to spacer devices used in conjunction with reinforcement structures for large concrete articles such as pipes, boxes and building structures. More particularly, the concept as related to spacers for use in maintaining concentric or parallel reinforcing assemblies in spaced relation relative to each other and to a form or mold in the fabrication of concrete structures. 
     II. Related Art 
     The manufacture of reinforced concrete structures often involves the use of a pair of steel mesh fabric shapes disposed in spaced parallel relation within the structure and spaced from the surfaces of the structure. In boxes, tanks, pipes or other enclosed structures, may resemble concentric mesh fabric cages and may be round, square, rectangular or other enclosing shape or even as sections of flat mesh for use in concrete walls. These reinforcing structures are typically welded wire or reinforcing rod (rebar) mesh fabric assemblies that may be characterized by a relatively dense lattice-weaving pattern which leaves relatively small openings through which the assemblies must be tied together in fixed relation by spacer elements to maintain the desired fixed space orientation both between the mesh structures and between the mesh structures and any molds for the casting or other pour operation. During the manufacturing process, particularly with precast shapes, various forces may be exerted on the double reinforcing mesh structures such as cage structures that may tend to separate the fabrics or tend to move them closer together. Twisting forces may also occur so that the spacers must be adequately secured to both fabrics, cages, etc. Pouring steps may be particularly stressful to the framework. 
     It is known to provide formed bent wire spacer elements to space a pair of wire reinforcing fabrics and to engage a form at one edge. These devices have been assembled and secured in place using wire ties or by being welded in place. More recently, spacer devices have been developed which can be manipulated into place without the use of ties or welds. Such devices are disclosed in Tolliver (U.S. Pat. No. 4,489,528) and Schmidgall et al (U.S. Pat. No. 4,999,965), for example. While these devices do space fabrics from each other and from mold walls, they require sections of wire or rods to be formed in intricate patterns that must be manipulated into place to attach to the mesh fabrics and that remains quite a labor-intensive assembly operation, even though welding or ties may not be necessary. 
     Thus, there remains a need for a spacer device for spacing, positioning and securing of spaced pairs of metal or other reinforcing fabric shapes in concrete structures that enables a less labor-intensive assembly and which enables the spacer devices themselves to be more easily fabricated from a variety of materials. 
     SUMMARY OF THE INVENTION 
     The present invention provides versatile spacer device designs for use wherever a plurality of reinforcing fabric shapes are employed in a concrete form. The spacers are easily installed even though very dense mesh weaves may be used and the devices lock into place with a minimum of manipulation. The spacers include a pair of spaced locking portions including first and second locking portions, each having a recess for receiving a fabric element and a trapping and retaining component for capturing and retaining a received fabric element. A generally straight central portion connects the pair of spaced locking portions and access to the pair of spaced locking portions is designed for positive attachment and ease of assembly. 
     The spacer is configured so that the first locking portion has an entrance directed generally such that the spacer can be inserted through an opening in the mesh of a first or near fabric and snapped onto an element of a second spaced fabric either by directly snapping onto the element or by hooking over the element and being retracted to lock the first portion onto the element of the second fabric. At this point, the second locking portion is configured such that it can be simply snapped directly onto a corresponding element of the first fabric. Thus, the first locking portion can have an entry directed away from the central portion or back toward the second locking portion but, in either case, assembly involves only a push-pull or linear motion and a finger grip may be provided on one end of the spacer element making assembly even easier. 
     A mold spacer extension can be provided on one or both ends of the spacer element depending on the particular application of the element. The distance between the locking portions and the size of the locking portions themselves can be varied such that spacers of different sizes can easily be fabricated. Spacers are preferably molded from relatively high-strength plastic materials, but metal components are also contemplated. 
     The spacer locking portions themselves include one integral inward directed capture member or a converging pair of opposed capture members extending generally at an angle from the entrance to the locking portion such that the capture member or members may be deflected resiliently by an object such as a rebar entering the locking portion so that the rebar or other element is captured and locked in place once beyond the inward directed member or members. Preferably, the locking portion includes a pair of opposed inward directed capture members for capturing and locking mesh elements such as a rebar section. 
     It will also be appreciated that the spacer of the present invention can be made as strong as desired by molding in a reinforcing rib or even using a metal core to increase the strength of the device. It will also be appreciated that the molded plastic spacers of the present invention will not corrode and deteriorate over time and will maintain their integrity. 
     The inventive concept also includes a composite double mesh fabric concrete reinforcing structure made using the spacers of the present invention and a method of assembling a concrete reinforcement structure utilizing the spacers of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings wherein like numerals depict like parts throughout the same: 
         FIG. 1A  is a top view of one embodiment of the spacer of the invention which includes mold spacers at both ends and may be used, for example, in a box pyramid locking device; 
         FIG. 1B  is a side view of the spacing device of  FIG. 1   a;    
         FIG. 1C  is an enlarged fragmentary detail circled at (C) in  FIG. 1B ; 
         FIGS. 1D and 1E  are top and side views of an alternate embodiment of the spacer having a single end spacer for use in, for example, a double cage system; 
         FIGS. 2A-2C  depict side views of alternate embodiments of the spacer element of the invention; 
         FIGS. 3A-3B  depict yet another embodiment of the inventive concept; 
         FIGS. 4A-4B  represent still another embodiment of the spacer element of the invention; and 
         FIG. 5  depicts a box pyramid lock showing a spacer in accordance with the invention in place. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description pertains to several embodiments of the inventive concept, each of which is presented by way of example rather than with any intent to limit the scope of the inventive concepts. It will be recognized that additional variations may occur to those skilled in the art which also would come within the scope of the inventive concept. 
       FIGS. 1A-1C  illustrate a typical spacer element in accordance with the invention. The spacer element is depicted generally at  10  and includes first and second locking portions  12  and  14  spaced by a generally straight central portion  16 . The structure includes a reinforcing rib  18  which runs the length of the structure  10  and is generally perpendicular to a central connecting fin  20 . A finger grip is provided at the vicinity of the second locking portion as shown at  22 . Each of the locking portions  12  and  14  includes a reinforcing fabric element receiving portion which might be a rebar engaging portion  24  with supporting segments and a pair of opposed integral inward directed capture members or retaining arms  28 . The inward directed capture members  28  are sufficiently resilient such that a heavy wire or rebar rod element, once encountered, can force them apart and enter the locking portion and come to rest in the engaging portion  24  in the manner of the spacer device being snapped onto the reinforcing mesh fabric elements which, once inside the locking portion cannot escape. Triangular shaped mold spacer portions  30  and  32  are provided that extend beyond both of the locking portions to space both sides of a double-fabric assembly from corresponding mold walls. 
       FIGS. 1D and 1E , show at  40 , an embodiment similar to that shown in  FIGS. 1A-1C  with the exception that only a single mold spacer portion  32  is provided. Such a spacer may be useful in assembling a reinforcing structure in an application such as a sanitary sewer, or the like, in which leakage through the structure in the vicinity of the spacers cannot be tolerated. 
     Alternate exemplary embodiments are illustrated in  FIGS. 2A-2C . In  FIG. 2A , there is shown an alternate embodiment  50  in which a first locking portion  52  has an entrance facing away from and generally parallel to the central portion  54  such that a spacer  50  can simply be inserted through an opening in the mesh of a first fabric and the locking portion  52  snapped directly onto an element of the spaced second fabric and then the second locking portion shown at  56  simply snapped onto a corresponding element of the first fabric without the need to maneuver or manipulate the spacer device further. That embodiment is shown with one mold spacer extension  58 , but it will be appreciated that an additional mold spacer may be provided to extend from the locking portion  52 , if desired. 
       FIG. 2B  illustrates yet another embodiment  60  in which the first and second spaced locking portions  62  and  64 , respectively, are arranged generally as in the embodiments of  FIGS. 1A-1E , however, this embodiment is produced without mold spacer extensions.  FIG. 2C  shows yet another embodiment  70  in which first and second locking portions  72  and  74  are provided with a single inward directed capture member or retention member as at  76  for retaining a captured reinforcement fabric element. Mold spacers are shown at  78  and  80 . 
     It will be appreciated that many other variations with respect to other embodiments are possible within the scope of the inventive concept. For example, any of the shown embodiments can be made with none, one or two mold spacer portions extending beyond the locking portions. In addition, any of the locking portions can be made using opposed pairs of capture or retention members or single capture or retention members. It will also be appreciated that double side-by-side locking portions can also be used having one or two retention members. 
     Additional alternate embodiments are shown in  FIGS. 3A-3B  and  4 A- 4 B. The embodiments of  FIGS. 3A-3B  illustrate a concept in which a spacer element  100  includes a central portion  102  which may be fabricated of a stamped metal shape which reinforces and connects spaced first and second locking portions  104  and  106 , respectively. A mold spacer extension is shown at  108 . In this embodiment, the first and second spaced locking portions  104  and  106  both include a pair of spaced locking portions as shown in  FIG. 3B . The two spaced locking portions provide two points of contact and capture with each of the spaced fabric elements to which the spacer is attached. This adds strength and stability to the system where necessary. The mold spacer element or mold spacer portion  108  also is configured to provide a finger hold at  110  for use in installing the spacer device  100 . 
     Yet another embodiment  120  is shown in  FIGS. 4A and 4B  in which a metal central portion  122  connects first and second spaced locking portions  124  and  126 . In this embodiment, the locking portion  126  is shown as a relatively wide portion compared to the locking portion  124 , however, both locking portions, together with a mold spacer extension portion  128 , are molded integrally with the metallic central connecting portion  122 . A finger-manipulating hold is shown at  130 . 
     The mold spacer portions in the various embodiments are shown as triangular or pyramidal in shape, however, they may be of any convenient shape and also, they may be of any desired length. This is also true of the central portions of the various embodiments inasmuch as the device may be made of any convenient length necessary to connect fabric configurations spaced at any convenient distance as they can be used to create a variety of reinforcement structures. 
     It will also be appreciated that it is an important aspect of the invention that all of the embodiments of the invention are constructed such that only a straight line or push-pull-type action is required to connect the first locking portion over a more remote fabric element. This can easily be accomplished by simply using finger grips provided on the opposite ends of the devices or by gripping the opposite end. Thus, the first locking portion can be easily used to capture the element of interest in a far fabric and the second or near locking portion snapped onto a corresponding element where leverage to do so is available at the near fabric. 
     The embodiments of  FIGS. 1A-1D  and  2 A- 2 C are generally designed to be fabricated of molded plastic materials, with or without internal reinforcing. It will be appreciated, however, that other materials such as reinforced fiberglass can be used as well. The embodiments of  FIGS. 3A-3B  and  4 A- 4 B combine metal and plastic materials to arrive at strong, easily assembled devices. 
     The spacers of the present invention are designed to join prefabricated cages or other configurations of meshed metal reinforcement structures which may be square, rectangular, round or any other shape so long as a pair of parallel structures are to be joined at a plurality of elements. The spacers of the invention can be applied to connect horizontal or vertical mesh fabric elements with equal ease. The reinforcing fabrics may be made of any stable reinforcing material, such as wire rebar or even fiberglass reinforced rod. Of course, the locking portions may be made of any size to best accommodate a particular size rebar or other mesh rod used in the reinforcing fabric. 
       FIG. 5  shows a spacer in accordance with the invention in place, connecting two mesh structures  150  and  152 , reinforcing box pyramid structure. The spacer shown in  FIG. 5  is provided with mold spacer portions  156  and  158  on both ends to space the network between two walls of a mold. It will be appreciated that while the invention has been described as connecting two mesh structures, three or more consecutive structures can be spaced and connected in the same manner, if desired. 
     This invention has been described herein in considerable detail in order to comply with the patent statutes and to provide those skilled in the art with the information needed to apply the novel principles and to construct and use embodiments of the example as required. However, it is to be understood that the invention can be carried out by specifically different devices and that various modifications can be accomplished without departing from the scope of the invention itself.