Patent Application
20110214381
The present invention relates to reinforcing bars (“rebars”) used in construction, and more particularly to retaining a rebar, a wire mesh, an electrical conduit, plumbing or other elongated bar in a desired configuration during construction.
Concrete is commonly used as a construction material because of its relatively low cost. Concrete is very strong in compression, but weak in tension. To increase the tensile strength of concrete, steel reinforcement bars (“rebars”) are added. For foundations, road work or other flat constructions, the rebar is often laid out in a grid pattern beneath the surface of the construction. To hold the rebar together in a grid, the bars are tied together where they intersect.
Various codes specify where the rebar must be placed. For example, the American Concrete Institute (ACI) in Section 318 of their code specifies that the rebar in a slab-on-grade foundation must be placed at the midpoint depth of the foundation. Thus, for example, in a four inch foundation slab, the rebar grid would normally be placed at a depth of approximately two inches. Consequently, the grid must be elevated off the ground to the desired position before concrete is poured. In many cases, concrete laborers use stones, pieces of broken bricks or materials to elevate the grid. This can cause the grid to be uneven or sag when the concrete is poured.
For concrete pillars and beams, the rebar is tied to a set of wooden frames and placed in a mold. The concrete is then poured into the mold to form the pillar, beam or other construction. However, this method suffers many disadvantages. First, it is difficult to align the rebar in parallel around the frames. Second, the frames often break or shift when the concrete is poured, causing the rebar to become misaligned. This reduces the tensile strength of the construction.
In one embodiment of the present invention, a support structure for retaining a reinforcing bar comprises a reinforcing bar engaging portion, where the reinforcing bar engaging portion comprises a receptacle to receive the reinforcing bar. The receptacle comprises a channel sized to receive the reinforcing bar, where the channel comprises a first portion and a bar retaining portion defined by sidewalls that extend radially outward from a first end to a second end. The retaining features are disposed on the walls of the channel, where the sidewalls are configured to spread so that the reinforcing bar passes the retaining features and rests in the bar retaining portion as the reinforcing bar moves down the channel. Additionally, the support structure comprises a support portion supporting the reinforcing bar engaging portion, where the support portion comprises a plurality of legs which project outward from a central axis. In addition, the support structure comprises a base configured to distribute weight of the support structure.
In another embodiment of the present invention, a support structure for retaining a wire mesh comprises a wire mesh engaging portion, where the wire mesh engaging portion comprises a receptacle to receive the wire mesh. The receptacle comprises a channel sized to receive the wire mesh, where the channel comprises a first portion and a bar retaining portion defined by sidewalls that extend radially outward from a first end to a second end. The retaining features are disposed on the walls of the channel, where the sidewalls are configured to spread so that the wire mesh passes the retaining features and rests in the bar retaining portion as the wire mesh moves down the channel. The support structure further comprises a support portion supporting the wire mesh engaging portion, where the support portion comprises a plurality of legs which project outward from a central axis. In addition, the support structure comprises a base configured to distribute weight of the support structure.
The foregoing has outlined rather generally the features and technical advantages of one or more embodiments of the present invention in order that the detailed description of the present invention that follows may be better understood. Additional features and advantages of the present invention will be described hereinafter which may form the subject of the claims of the present invention.
A better understanding of the present invention can be obtained when the following detailed description is considered in conjunction with the following drawings, in which:
Embodiments described herein provide systems for retaining a rebar, a wire mesh, an electrical conduit, plumbing or other elongated bar in a desired configuration during construction. Embodiments described herein will be described primarily in the context of a rebar, but it should be understood that the embodiments are not limited to rebars and can be used to retain other types of bars.
Support structure 100 can be formed of a suitable material, such as resilient plastic or other material, and can be manufactured to surpass requirements from the Uniform Building Code, International Building Code, American Concrete Institute, American Association of State Highway and Transportation Officials and standard practices as specified by the American Concrete Institute, the Concrete Reinforcing Steel Institute and other requirements. According to one embodiment, support structures 100 can be manufactured to have a capacity exceeding expected construction loads, which typically range between 250-300 pounds. Support structures 100, according to one embodiment of the present invention, can have a critical load in axial compression of 320 pounds or more. According to one embodiment, support structures 100 can have a critical load in axial compression of approximately 400 pounds. Other embodiments can have higher or lower critical loads as needed or desired. In one embodiment, support structure 100 can be configured so that it does not require ties or caps to retain the rebar.
Crown 107 can be used in a variety of applications for supporting the rebar in cement, including, but not limited to, foundations and cement beams. Rebar engaging portion 102 comprises one or more receptacles to receive the rebar. In the case of
According to one embodiment, each set of paired receptacles can be sized to fit different sizes of rebar. In other embodiments, each set of paired receptacles can be sized to fit the same size of rebar. The depth of bar receptacles 110, 112 and 114 can be offset from each other so that the bars supported by engaging portion 102 can cross each other at the center of engaging portion 102. The bar receptacles of engaging portion 102 can be positioned so that the bars cross at a 90 degree angle or other desired angle. The bar receptacles can be snap-fit receptacles that allow a bar to be fully inserted by a human while inhibiting removal of the bar. The snap fit can provide feedback to the user so that the user knows when the bar has been sufficiently inserted and can result from the spring action of the bar receptacles.
Support portion 104 provides supports such as a plurality of leaves or legs 116 which project outward from a central axis and support rebar engaging portion 102. Support portion 104 can include any number of legs 116 or supports and the legs can have various configurations. Various embodiments of legs 116 are discussed below. Legs 116 can include feet 118 on which support portion 104 rests. According to one embodiment, each leg 116 can taper toward the respective foot 118 to leave area 120 open. This can allow concrete to flow beneath the legs 116 and between the feet 118.
Base 106 can be shaped to distribute weight. In the embodiment of
Additionally, base 106 can include foot receptacles 124. Foot receptacles 124 can be sized and positioned to receive the feet of a different sized crown 107. Thus, a single base can be made for use with interchangeable crowns 107.
Having a separate crown 107 and base 106 provides many advantages over existing systems. Crown 107 can be used in a number of applications with or without base 106 as needed or desired. Using crown 107 without base 106 provides advantages over prior art rebar chairs described in U.S. Pat. No. 6,282,860 (the “'860 patent”). When the rebar chairs of the '860 patent are used in the construction of concrete beams, the bases of the chairs will typically show through the side of the beam as large unsightly rings. This requires the beam to be painted or have another coating applied to hide the rings. Crowns 107 of the present disclosure, on the other hand, can be used without bases 106 and therefore will not leave exposed rings. In this case, if a portion of a crown 107 shows, it is only the bottom of the feet 118, which is a very small area. The same type of crown 107 can be used with base 106 in applications that require more stability or weight distribution, such as building over soft earth or sand. Thus, the same model of crown has different modes of operation.
In operation, the rebar can be inserted in a first portion 138 of channel 130. As the rebar moves down channel 130, sidewalls 132 can spread slightly so that the rebar can pass bumps 137 and rest in bar retaining area 139 on base 141. According to one embodiment, bumps 137 snap over the bar to inhibit the bar from coming out of channel 130. The material, thickness or other properties of sidewalls 132 can be selected so that the rebar can be inserted manually.
The receptacles can be joined to each other by arms 143. According to one embodiment, the sidewalls of the receptacles and arms can be formed by a continuous, unitary shaped rib of material that projects radially outward from a first edge near the center of crown 107 to an outer edge. The rib can be laid out in an annular shape with an opening or gap between paired receptacles. Thus, each receptacle, according to one embodiment, does not extend to the base of the paired receptacle (e.g., the base 141 of receptacle 110a does not extend across engaging portion 102 to the base of receptacle 110b). Instead, there may be a gap between the paired receptacles at the center of crown 107.
Rebar running in a first direction can be snapped into the crowns (step 206). If rebar running in another direction is to be used, the rebar can be snapped in the crowns in a second direction (step 208). The rebar running in the first direction may be at any angle as allowed by the crown up to 90 degrees from the rebar running in the second direction. If different sizes of rebar are used, the larger rebar is snapped in over the smaller rebar. However, in other embodiments, the smaller rebar can be snapped over the larger rebar. The steps of
While embodiments above have been discussed in the context of rebar, embodiments of the present application can be used with graphite tubing, glass tubing, plumbing, conduit, wire mesh, or any other elongated rod.
As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, product, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, article, or apparatus. Further, unless expressly stated to the contrary, “or” refers to an inclusive or and not to an exclusive or. For example, a condition A or B is satisfied by any one of the following: A is true (or present) and B is false (or not present), A is false (or not present) and B is true (or present), and both A and B are true (or present).
Additionally, any examples or illustrations given herein are not to be regarded in any way as restrictions on, limits to, or express definitions of, any term or terms with which they are utilized. Instead these examples or illustrations are to be regarded as being described with respect to one particular embodiment and as illustrative only. Those of ordinary skill in the art will appreciate that any term or terms with which these examples or illustrations are utilized encompass other embodiments as well as implementations and adaptations thereof which may or may not be given therewith or elsewhere in the specification and all such embodiments are intended to be included within the scope of that term or terms. Language designating such non-limiting examples and illustrations includes, but is not limited to: “for example,” “for instance,” “e.g.,” “in one embodiment,” and the like.
Further modifications and alternative embodiments of various aspects of the disclosure will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the disclosure. It is to be understood that the forms of the disclosure shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the disclosure may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the disclosure. Any dimensions provided are provided by way of example only and not limitation. Changes may be made in the elements described herein without departing from the spirit and scope of the disclosure.
This application is related to the following commonly owned co-pending U.S. Patent Application: Provisional Application Ser. No. 61/309,787, “System and Method of Supporting Rebar with Interchangeable Crowns,” filed Mar. 2, 2010, and claims the benefit of its earlier filing date under 35 U.S.C. §119(e).
| Number | Date | Country | |
|---|---|---|---|
| 61309787 | Mar 2010 | US |
