Patent Application
20130186030
There are numerous concrete products used in the construction industry in a variety of applications, such as foundations for supporting structures, as bridge and deck panels, and as beams for structures, just to name a few. Concrete is a material that is very strong in compression but relatively weak in tension. Masonry structures and the mortar holding them together have similar properties to concrete and also have a limited ability to carry tensile loads.
In order to compensate for this imbalance in the behavior of concrete and masonry structures, reinforcement bars, which are common steel bars, are typically used as a tensioning device to produce reinforced concrete and reinforced masonry structures. These reinforcement bars, commonly called “rebars”, are usually formed from carbon steel, and are given ridges for better mechanical anchoring into the concrete. While any material with sufficient tensile strength could conceivably be used to reinforce concrete, steel and concrete have similar coefficients of thermal expansion. Therefore, a concrete structural member reinforced with steel will experience minimal stress as a result of differential expansions of the two interconnected materials caused by temperature changes.
Traditional reinforced concrete is based on the use of rebars cast into a poured concrete structure. In addition, pre-stressed concrete is a method for further overcoming concrete's natural weakness in tension. It can be used to produce beams, floors or bridges with a longer span than is practical with ordinary reinforced concrete. Pre-stressing tendons, generally of high tensile steel cable, are used to provide a clamping load which produces a compressive stress that balances the tensile stress that the concrete compression member would otherwise experience due to a bending load.
One concrete product that utilizes the foregoing principles is a prefabricated concrete pile used to support foundations. These piles are driven into the ground using a device such as a pile driver. Concrete piles are available in a variety of cross-sectional shapes, including square, octagonal, and round cross-sections, and they are reinforced with rebar and are often pre-stressed. Foundations relying on concrete driven piles often have groups of piles connected by a pile cap (a large concrete block into which the heads of the piles are embedded) to distribute loads which are larger than one pile can bear. Pile caps and isolated piles are typically connected with the piles to tie the foundation elements together, so that lighter structural elements bear on the piles while heavier elements bear directly on the pile cap.
In the manufacture of reinforced and pre-stressed concrete structures, such as piles, a form of the desired shape is used with reinforcing spaced-apart steel bars positioned to create a frame. Then rebars or grout tubes are used to further strengthen the structure. When utilized, the rebars or grout tube must be centered and held in place as the concrete is poured to form the structure. Securing the rebars or grout tube within the steel bar frame is currently done by hand, using wires and cables to tie the rebars or grout tube to the frame. This is a time consuming and expensive process.
There is therefore a need for an improved way of securing a grout tube and rebars in place while the concrete is poured to form the concrete structure.
The invention is for preformed wire spacers that are shaped to grasp a grout tube and secure it to the steel frame within a concrete form. The spacer is formed from a continuous length of spring steel, wire that has a circular central portion of sufficient size to surround the grout tube. The free ends of the spacer extend outwardly from the central portion and are formed with hooks extending, with one free end having both a handle and a hook. Being a continuous length of spring steel, the central portion has a double wrap or overlapping portion which provides for the diameter of the central portion to be temporarily expanded in diameter by grasping the free ends and applying force to expand the central portion's size. This allows the spacer to be easily combined with the grout tube, since the spacers and tube can move relative to each other. Multiple spacers are used on a single tube and are spaced apart a distance to provide the proper support and positioning of the tube relevant to the frame and the finished concrete form.
In the preferred embodiment, the central portion 22 transitions to the free ends 24, 26 at an angle. Additionally, the angle designated as A in
Free end 24 has a fastener 27 which is preferably a hook 28 formed at its outer end 29 while free end 26 has a fastener 31 again preferably a hook 32, and a handle 34 at its outer end 35. The hooks 28, 32 engage a frame 40 of a future concrete structure as shown in
Handle 34 provides a grip for installing the spacer 20 by first securing the hook 28 over a portion of the frame 40 or cable 46 after which handle 34 is grasped to secure the hook 32 over a portion of the frame 40 or the cable 46 on the opposite side of the frame 40. Again, the angle of the handle 34 and the hook 32 can be varied, however, the angle designated as B shown in
The curved portions 50 of the spacer 20 are contiguous and form a secondary structure 52 in the central portion 22. Preferably the curved portions 50 touch against each other within at least a portion of the central portion 22, as shown in
Once spacers 20 are installed on the frame 40, a grout tube 12 can easily be slid through the spacers which position the grout tube 12 in the approximate center of the form resulting in a finished product as shown in
As is well known to those skilled in the art, a typical concrete pile or beam 10 is produced in a concrete form (not shown) of the desired length and cross-sectional shape. Referring to
Although it is contemplated that the spacer 20 will have a set diameter “d” for accommodating a specific sized grout tube, the size of the spacer 20, particularly the diameter of the central portion 22 can be varied during the manufacturing process to accommodate a specific sized grout tube. Additionally, the preferred material used to make the spacer 20 is spring steel which allows the spacer to have some flexibility. The flexibility allows the spacer 20 to go from its static first position to a second position when force is applied on the free ends 24, 26 toward the center portion 22. This application of force expands the diameter of the center portion 22. The greater the force applied the greater the expansion of the diameter of the center portion. Once the force is released, the spacer 20 returns to its normal first position. The ability to expand allows a particular spacer 20 to accommodate a variety of sizes of grout tubes.
The above description is for a preferred embodiment. There are numerous contemplated changes to the spacer which could vary from the preferred embodiment. Beginning with the free ends 24, 26, a variety of fasteners, other than hooks, with the ability to engage a portion of the frame 40 or cables 46. Similarly, the shape of the center portion 22 could be varied without making the spacer 20 inoperable. Furthermore, another embodiment could utilize a center portion 22 which does not entirely wrap around the grout tube. Instead, the center portion 22 could be a semi circle which wraps around only a portion of the grout tube 12. For instance, if the center portion wrapped the left side of the grout tube 12, then the next flanking spacer 20 could wrap the right side of the grout tube 12. Accordingly the grout tube 12 could be secured within the frame 40 without a complete circular center portion 22.
Having thus described the invention in connection with certain embodiments, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the invention.
The present application claims priority to provisional patent application 61/588,271 which was filed on Jan. 19, 2012, and is hereby expressly incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61588271 | Jan 2012 | US |
