Patent Application
20110219721
1. Field of the Invention
The present invention relates generally to the field of reinforced concrete. More specifically, the present invention discloses a spacer for positioning reinforcing mesh in concrete.
2. Prior Art
Reinforcing mesh has long been used to enhance the structural properties of concrete. This mesh is typically a rectangular grid of steel reinforcing strands that is positioned in a concrete form and then becomes embedded in the concrete when the form is filed with wet concrete. A wide variety of spacers have been used in the past to hold the reinforcing mesh in a desired position within a form, so that the mesh will have the desired location and depth within the finished concrete slab or component.
A number of criteria must be considered in designing a suitable mesh spacer. Large numbers of mesh spacers are required for large construction projects, which dictates that manufacturing costs and installation costs at the job site are major factors. In particular, many conventional mesh spacers are made of steel and have very sharp edges that can injure workmen. Steel mesh spacers also rust, which can reduce the structural integrity of the concrete. The present invention addresses these requirements by providing a plastic mesh spacer that is simple and expensive to manufacture and install, and that minimizes the risk of injury to workers.
This invention provides a mesh spacer for reinforced concrete having vertical members that extend outward with an X-shaped cross-section. The horizontal dimensions of the spacer allow it to be inserted into an opening in a lower layer of reinforcing mesh in a first orientation (i.e., an orientation with the vertical members diagonal to the reinforcing strands of the mesh). Notches in the lateral edges of the vertical members engage the reinforcing strands of the lower layer of mesh in a second rotational orientation of the spacer (i.e., an orientation with the vertical members parallel to the reinforcing strands of the mesh). An upper layer of mesh can be placed on the top surfaces of the vertical members and secured with ties that pass through openings in the vertical members.
These and other advantages, features, and objects of the present invention will be more readily understood in view of the following detailed description and the drawings.
The present invention can be more readily understood in conjunction with the accompanying drawings, in which:
Turning to
The mesh spacer has bottom surfaces that serve as the feet to support the spacer in a concrete form. It also has top surfaces for supporting an upper layer of reinforcing mesh 40, as will be discussed below. A number of windows or openings 14, 16 extend through the vertical members of the mesh spacer. These openings 14, 16 allow concrete and aggregate to flow around and through the mesh spacer, thereby reducing the chance of voids and creating a mechanical bond between the mesh spacer and the concrete.
The lateral edges of the vertical members 10, 11 each include at least one notch 12 at a uniform vertical distance from the bottom of the mesh spacer. These notches 12 should be sufficiently large to effectively engage the reinforcing mesh grid, as will be described below. In addition, the overall dimensions of the mesh spacer in a horizontal plane must be carefully selected based on the corresponding dimensions of the reinforcing mesh. As previously mentioned, conventional reinforcing mesh 30 is typically made of an orthogonal grid of metal reinforcing strands that define an array of rectangular openings having standard dimensions. The horizontal cross-sectional dimensions of the mesh spacer must be sufficiently small to allow the mesh spacer to be inserted into the openings in the reinforcing mesh 30 when turned in the diagonal orientation shown in
In use, each mesh spacer is initially inserted into an opening in a layer of reinforcing mesh 30 as shown in
After the mesh spacer has been inserted to an elevation at which its notches 12 align with the mesh 30, the mesh spacer is rotated about the normal axis as shown in
A second, upper layer of reinforcing mesh 40 can then be placed atop the mesh spacers and secured with a number of ties 20, as shown in
An array of mesh spacers may be used to support a large pieces of reinforcing mesh 30 as illustrated in
It should be noted that the mesh spacer can be easily removed and relocated, if needed. It can be readily detached from the upper layer of reinforcing mesh 40 by cutting or untwisting the ties 20. The mesh spacer can also be readily detached from the lower layer of reinforcing mesh 30 by rotating the mesh spacer a quarter turn to a diagonal orientation and then lifting it out of the opening in the mesh 30.
After assembly of the mesh spacers and reinforcing mesh, concrete can then be poured into the form to cover the mesh spacers and both layers of reinforcing mesh 30, 40. The openings 14, 16 in the mesh spacer allow concrete to freely flow through the mesh spacer so that it becomes an integral part of the finished concrete slab. The mesh spacers remain embedded in the concrete slab along with the reinforcing mesh 30, 40 as the concrete cures. It should be noted that the mesh spacers can be stacked in a variety of configurations, if additional layers of reinforcing mesh are required for a particular job.
The mesh spacer can be made of any suitable material, including plastic, metal, or composite materials. In the preferred embodiment, the mesh spacer is made of polypropylene. This material is light weight, relatively inexpensive, dimensionally consistent, doesn't rust, and has no sharp edges that might injure workers.
The mesh spacer can be formed as a single piece or assembled from two or more planar pieces. In the preferred embodiment shown in the figures, the vertical members are mold for plastic as two separate pieces. Complementary slots 18, 19 in both pieces enable the vertical members 10, 11 to slide together in an orthogonal arrangement as depicted in
It should be understood that alternative shapes and configurations of the mesh spacer and the vertical members could be readily substituted. For example, the vertical members are not necessarily planar or orthogonal. The number of vertical members could also be changed. More than one notch 12 could be provided on each lateral edge of the vertical members to accommodate a variety of elevations for the lower reinforcing mesh, or allow a plurality of lower mesh layers. The structural rigidity of the mesh spacer could be enhanced by including a central body or shaft with vertical members extending radially outward.
The above disclosure sets forth a number of embodiments of the present invention described in detail with respect to the accompanying drawings. Those skilled in this art will appreciate that various changes, modifications, other structural arrangements, and other embodiments could be practiced under the teachings of the present invention without departing from the scope of this invention as set forth in the following claims.
