Patent Application
20070209310
The invention relates generally to a solid, reinforced and pre-wired rebar support apparatus that supports, positions and firmly secures rebar in a footing. The apparatus is for use in supporting and securing rebar in the footings and foundations of buildings during a concrete pour.
Rebar support structures of one type or another have been used for many years in the construction industry to hold panels or walls in fixed relation while concrete is poured. Most often, the rebar support contains twisted wire, which serves to hold the rebar securely in place. Previous attempts have been made to improve the rebar support structures, certain features of which are generally described in U.S. Pat. No. 6,883,289 to Juedes et al; U.S. Pat. No. 6,837,017 to Hardy, Jr. et al.; U.S. Pat. No. 6,732,484 to Sotelo et al.; U.S. Pat. No. 6,629,393 to Pignataro; U.S. Pat. No. 6,571,526 to Queen; U.S. Pat. No. 6,526,721 to Nash; U.S. Des. Pat. No. D483,246 to McPherson; U.S. Pat. No. 6,354,054 to Verelli et al.; U.S. Pat. No. 5,819,493 to LeMoignan; U.S. Pat. No. 5,664,390 to Sorkin; U.S. Pat. No. 5,456,051 to Queen et al.; U.S. Pat. No. 4,756,641 to Hartzheim; U.S. Pat. No. 4,644,727 to Hanson et al.; U.S. Pat. No. 4,598,523 to Tolliver; U.S. Pat. No. 3,728,836 to Gates; and U.S. Pat. No. 1,268,887 to A. F. Schroeder, all of which are incorporated herein by reference.
U.S. Pat. No. 6,883,289 to Juedes et al. (the '289 patent) describes an apparatus and method for suspending and positioning structural reinforcement elements such as rebar within a framework for a slab-on-grade foundation or other type of concrete structure. Each rebar support comprises a plurality of rebar support arms that connect to other components of the foundation or concrete structure, and support one or more pieces of rebar in a desired orientation. The rebar support does not use tie wires, rather claps onto the rebar. The rebar support must be supported by a pre-existing tendon support in the structure.
U.S. Pat. No. 6,837,017 to Hardy, Jr. et al. (the '017 patent) describes a transverse bar assembly for use in constructing rebar mats for reinforcement of concrete paving. The assembly is capable of supporting and securing longitudinal reinforcing steel rods at their designed location and spacing in such a manner as to prevent the rebar mat from being displaced during concrete placement. The assembly includes a plurality of chairs and clips each having a lower portion that fixes to a transverse bar in the direction of its length and an upper portion for orthogonally receiving and holding locked in place a longitudinal bar. The chair also has a support extending to a base surface.
U.S. Pat. No. 6,732,484 to Sotelo et al. (the '484 patent) describes a chair support for metal reinforcements for use during a concrete pour. The chair is box shaped having grooves in the side walls of different width for supporting rebar of different diameter. Notches in the edge of the grooves on opposite sides of the chair support wire mesh of different diameter. The notches are shaped so that the wire mesh is snapped into the notch. Wall like braces extend across the inside of the chair and support the grooves from the opposite wall. The larger grooves are on the short sides of the chair to raise the rebar a longer distance off the underlying surface.
U.S. Pat. No. 6,629,393 to Pignataro (the '393 patent) describes a masonry reinforcing tie. The tie is formed of a pair of spaced apart, parallel elongated elements joined by a series of lateral cross members welded or otherwise affixed across the elongated members. The elongated members and cross members are preferably formed of heavy metal wire or rod. The elongated members each include a series of spaced apart joint spacing elements formed integrally therewith, with the spacing elements having a height equal to the standard mortar joint thickness. Use of the tie permits a person to lay multiple vertically stacked blocks or bricks neatly and evenly, assuring that the horizontal mortar joints are even and consistent.
U.S. Pat. No. 6,571,526 to Queen (the '526 patent) describes a concrete masonry unit vertical reinforcement and anchor bolt positioning device. The device positions reinforcement bar within a masonry block. The positioning device includes a core with a central opening and an openable seam, a support structure having support arms connected to the core and arranged and configured for holding the positioning device in a desired position in a cavity of the masonry block. The core is arranged such that a gap can be formed along the seam, the gap being configured to receive the reinforcement bar, and the core encloses the reinforcement bar within the central opening when the gap is closed.
U.S. Pat. No. 6,526,721 to Nash (the '721 patent) describes a fluid-impervious barrier/keyway form support apparatus, system and method. The support carries the barrier and a pair of spaced legs for attachment to a corresponding pair of stable mounting points, such as reinforcement members. The support is positioned such that the barrier is at least partially covered by concrete during the pouring of a first slab and then the remainder is covered when a second concrete slab is poured atop the first slab.
U.S. Des. Pat. No. D483,246 to McPherson (the '246 patent) describes a rebar chair. The patent covers an ornamental design of a rebar chair. The rebar chair includes support legs attached to rebar claps for holding the rebar a certain distance above the ground level.
U.S. Pat. No. 6,354,054 to Verelli et al. (the '054 patent) describes a rebar support system including a rebar chair with four legs between which there are defined two intersecting passages for receiving the intersecting portions of two rebars. The rebars are suspended by a fastening wire or supported by an auxiliary chair below the apparatus. The legs forming one of the passages have a uniform spacing and are adapted to closely straddle the rebar extending through the same. The legs of the second passage flare downwardly so that their spacing progressively increases from the body to the free ends from a spacing smaller than to a spacing greater than the uniform spacing between the legs of the first passage. A saddle is formed on the top of the body for supporting a third rebar.
U.S. Pat. No. 5,819,493 to LeMoignan (the '493 patent) describes a height adjustable rebar support system for supporting rebar at various elevations during pouring and curing of concrete with a single adjustable support member. The support includes a first panel having a first lower slot, a second panel pivotally attached to the first panel having a second lower slot, an aperture and a notch into the first panel near the first lower slot, and a beaded cord secured to the second panel. The end of the beaded cord opposite of the second panel selectively engages the first panel through the aperture thereby adjusting the separation of the first panel with respect to the second panel.
U.S. Pat. No. 5,664,390 to Sorkin (the '390 patent) describes a bolster for use in construction. The bolster includes a plurality of leg members arranged in parallel relationship and a beam integrally formed with the plurality of leg members and extending across the leg members. The beam includes connectors, which serve to connect adjacent bolsters.
U.S. Pat. No. 5,456,051 to Queen et al. (the '051 patent) describes a compression spacer for bar reinforcement. The spacer includes a support base and a receptacle welded together at interfitting angular flanges. A bearing plug includes a circular support plate covering the upper surfaces of the radial walls with a tapered stem projecting into a tapered center opening of the support base. The flexible engagement fingers allow one way movement of the rebar rod into the receptacle and the protrusions of the rod engage the ends of the fingers prohibiting separation of the spacer support and the rod.
U.S. Pat. No. 4,756,641 to Hartzheim (the '641 patent) describes a sand plate and concrete reinforcement support. A flat, disk-shaped sand plate is disposed in contact with the earthen bed and has a plurality of channels adapted to receive pedestal feel extending upwardly from its top surface and radially from its center toward the periphery. A pedestal is disposed atop the sand plate with feet wedged into the pedestal fool channels. The reinforcement bar is cradled atop the pedestal.
U.S. Pat. No. 4,644,727 to Hanson et al. (the '727 patent) describes a strand chair for supporting cable and cross-mesh in elongated precast concrete plank. The chairs include a lower chair portion for supporting multiple prestressing cables at the bottom of a plank and a narrow upper chair portion for supporting an upper prestressing cable located in the web between the hollow core of the prestressed plank. The upper chair portion can be inserted into the strand receiving cups of the lower portion to form a structurally sound support for accurately placing the top and bottom reinforcing strands in the plank as it is cast.
U.S. Pat. No. 4,598,523 to Tolliver (the '523 patent) describes a reinforcement support spacer for spacing one or more concrete reinforcement members from a surface on which concrete is poured. The spacer comprises a support which has at least one recess therein for receiving a reinforcement member. Barbs or tines formed integrally with the support project into the recesses. The barbs or tines on each recess are oriented so as to permit a reinforcement member to be forced past the barbs or tines into the recess, but substantially to prevent a reinforcement member from being forced passed the barbs or tines out of the recess once a reinforcement member has been inserted into the recess. The support spacers of the present invention permit reinforcement members to be preassembled in spaced relationship to each other.
U.S. Pat. No. 3,728,836 to Gates (the '836 patent) describes a concrete form tie and rebar chair. The twisted wire concrete form tie is characterized by a lower single-wire strand joined to an upper double-wire twisted section by a pair of return bends at opposite ends, all of which cooperate with one another to define an elongated endless loop. The portions of the length of wire that are laid side by side and twisted together to form the twisted section terminate in free ends that are bent to form upstanding stops with upwardly opening generally U-shaped rebar saddles on the inside thereof. The section of the return bend projecting outwardly beyond the adjacent stop is slightly longer on one end than the other.
U.S. Pat. No. 1,268,887 to A. F. Schroeder (the '887 patent) describes a reinforcing device or a tie brace. The tie brace connects to and holds reinforcing rods in proper spaced relation during the pouring of concrete. The tie brace is I-shaped and adapted for use in the manufacture of concrete I-beams or trussed flooring, in which a plurality of extending rods are to be embedded.
As used herein, the term “rebar” refers to a length of metal bar, often steel, which is placed into a footing before concrete is poured. It shall be understood that rebar is available in many grades and diameters. The term “splice” shall refer to the point where one piece of rebar ends and is lapped by the next piece of rebar. The lap distance is generally 48 times the diameter of the rebar used. The term “tie wire” as used herein shall be understood to mean wire which is used to fasten and maintain rebar in a particular position at splices and in a rebar support apparatus during concrete installation. The term “keyway” shall be used herein to represent a method of bonding masonry and concrete structures so as to prevent slippage and shear. The keyway is commonly a recessed area of one surface to accept a protruded portion of another. As used herein, the term “transverse rebar” shall mean rebar that is installed in a diagonal or perpendicular position to the main continuous runs of rebar. Transverse rebar may be required in a footing containing three or more continuous runs of rebar or a footing designed to support columns. As used herein, a “beam” is a horizontal unit designed to support an additional load. The term “footing” shall mean a self-supporting arrangement of rebar embedded in concrete, which will carry the entire load of the structure. The term “compressive strength” shall be understood to mean the capacity of a material to withstand axially directed pushing forces. When the limit of compressive strength is reached, materials are crushed.
Generally, the compressive strength of concrete normally improves with time. The ability of concrete to resist failure is enhanced by the use of reinforcement. Of utmost importance in any structure is the footing. Upon failure of the footing, the structure will fail. Installing all the necessary components of a footing can be labor intensive. The rebar must be installed and tied in place at a specific clearance and spaced a particular dimension from each other. The rebar must also be placed with attention to maintaining a minimal clearance from the bottom and sides of the footings containment area. The rebar support system must also withstand the tremendous forces encountered when the cement is poured. In many cases, when the cement is poured, the rebar support apparatus shifts and fails. Several conditions can contribute to the failure, such as welded wire collapsing, plastic rebar support apparatus collapsing, rusty tie wires snapping, or rebar moving when the cement is poured and ending up positioned incorrectly. Typical welded wire support apparatus devices, which are composed of three or more pieces of heavy gauge wire welded together, can puncture the moisture barrier membrane it rests on when weight or friction is applied to the apparatus. The puncture of the moisture barrier membrane allows moisture migration to originate around where the wire support apparatus is welded.
None of the methods and apparatus mentioned above describe a rebar support apparatus that includes a cement base with reinforced steel and tie wire embedded within the body of the rebar support apparatus, where the tie wire extends out of the body and secures rebar that rests in recessed depressions and wherein the body achieves a compressive strength of about 3,000 p.s.i. There is no known rebar support apparatus that achieves a compressive strength of about 3,000 p.s.i. and which serves to hold and secure the rebar in particular positions while cement is being poured through the use of embedded tie wires. Moreover, there is a need to eliminate the use of transverse rods, which are required in most footings containing three or more continuous lengths of reinforcing steel. Accordingly, there is a need in the art for an apparatus for use in supporting and securing rebar during a concrete pour that comprises a body made of a cement mixture having a triangular shape that includes a reinforcement structure located centrally within the body and recessed depressions wherein rebar is to be seated and secured. It is also desired for the apparatus to contain tie wires that are wound around the reinforcement structure and embedded into the body. The ends of the tie wires emanate from either side of the depressions and are twisted around the rebar, after the rebar is positioned, to secure the rebar and prevent it from shifting during the concrete pour.
The current invention satisfies the above needs by providing an apparatus that supports and positions rebar in a footing. It can be fashioned to accept any orientation of rebar. Each rebar support apparatus consists of tie wires wound to a piece of reinforcement. The rebar support apparatus is formed of both fine and lightweight cement aggregates combined into a specific mix. Integrated into the rebar support apparatus is sufficient reinforcement to rate it as a structural beam. Also embedded into the rebar support apparatus are wire ties which determine proper location for rebar in every direction. The rebar support apparatus is a solid member whose reinforcement and tie wire system is completely protected from moisture migration. The risk of the rebar support apparatus shifting or crushing during concrete installation is virtually non-existent. The rebar support apparatus can act as a substitute for transverse rods required in most footings containing three or more continuous lengths of reinforcing steel.
The invention provides a keyway molded along the side of the rebar support apparatus. Along the top of the rebar support apparatus are several recessed depressions which accept rebar. On each side of each depression, a corrosion resistant wire extends upwards. The wire is embedded in the rebar support apparatus where it forms a loop around, or is wrapped around, the equally embedded section of reinforced steel. The rebar support apparatus is poured in forms or casting moulds in a plastic state and consists of Portland cement, sand and some lightweight aggregates to achieve a compressive strength of nearly 3000 p.s.i. The reinforcing steel along with the wires are wet-stuck into the bench while it is still in a workable state.
The current invention also provides an apparatus for use in supporting and securing rebar during a concrete pour comprising a body having a triangular shape including a base and an apex, wherein the base forms a stable surface which rests on the ground or other suitable level building surface. The apparatus includes a reinforcement structure located centrally within the body, at least one depression in the apex of the body, wherein rebar is seated, and at least one tie wire, wherein the tie wire is wound around the reinforcement structure and emanates from either side of the depression and is twisted around the rebar, after the rebar is set in place, to secure the rebar and prevent it from shifting during the concrete pour.
The current invention further provides for a rebar support apparatus comprising a horizontal body with a base width of about three and a half inches and a height of about three and a half inches, wherein the horizontal body is composed of a cement mixture. The rebar support apparatus also includes at least one rebar receiving depression on a upper surface of the horizontal body, at least one reinforcement structure located within the horizontal body, at least one tie wire to secure the rebar into the receiving depression, wherein the tie wire is wound around the reinforcement structure with each end of the tie wire emanating from the horizontal body on either side of the rebar receiving depression, and at least one keyway along each side of the horizontal body.
The invention provides an apparatus for use in supporting and securing rebar during a concrete pour comprising a body having a triangular shape including a base and an apex, wherein the base is a bottom surface and the apex is an upper surface, wherein the body is composed of one and a half part course sand, one part Portland cement and one part vermiculite and wherein the length of the body may range from about ten inches to about five feet. The apparatus includes a reinforcement structure located within the body, wherein the reinforcement structure is a steel rod which strengthens the body and enables it to withstand about 3,000 p.s.i. before type one failure. The apparatus also includes at least one keyway along the side of the body, at least one depression formed in the apex of the body, wherein rebar is seated and secured; and at least one tie wire, wherein the tie wire is wound around the reinforcement structure and embedded in the body such that at least three inches of tie wire emanates from either side of the depression, and wherein the tie wire is twisted around the rebar, after the rebar is set in place, to secure the rebar and prevent it from shifting during the concrete pour.
These and other objects, features, and advantages of the present invention may be better understood and appreciated from the following detailed description of the embodiments thereof, selected for purposes of illustration and shown in the accompanying drawings.
The solid, reinforced and pre-wired rebar support apparatus provides support and positioning for rebar in a footing. Such a support apparatus is also called a “rebar bench”. The rebar support apparatus can be fashioned to accept any orientation of rebar.
As shown in
The interval between the rebar depressions 6 depends upon the use of the rebar support apparatus 1 and the load intended to be supported. In residential construction, the rebar support apparatus 1 is approximately ten inches (10″) in length. This allows for a one inch (1″) clearance on each side when a twelve inch (12″) site has been excavated. A typical rebar support apparatus 1 for residential use would contain two depressions 6 and hold the rebar 5 about six inches (6″) apart. In commercial construction or when the rebar support apparatus 1 is used to support columns, the typical rebar support apparatus 1 may be up to five feet (5′) in length. In such commercial uses, there may be from seven (7″) to eleven inches (11″) between the rebar 5.
The tie wires 4 serve to further secure the rebar 5 in place. As shown in
The rebar support apparatus 1 can be poured and vibrated or extruded. The rebar support apparatus 1 is most preferably composed of a cement mixture of one and a half part course sand, one part Portland cement, and one part vermiculite, such as zoelite or perlite. The necessary amount of water is also added to the mixture. Typically, the cement mixture includes two-thirds (⅔) part water, but will vary as humidity and moisture content of the dry materials will vary. Portland cement is defined by ASTM C 150 as hydraulic cement (cement that not only hardens by reacting with water but also forms a water-resistant product) produced by pulverizing clinkers consisting essentially of hydraulic calcium silicates, usually containing one or more of the forms of calcium sulfate as an inter ground addition. Clinkers are nodules of a sintered material that is produced when a raw mixture of predetermined composition is heated to high temperature. The low cost and widespread availability of the limestone, shales, and other naturally occurring materials make Portland cement one of the lowest-cost materials widely used over the last century throughout the world. Vermiculite is a member of the phyllosilicate group of minerals, resembling mica in appearance. Vermiculite is designated or named pursuant to two systems, Systems A and B, both of which depend upon the size of the particles. The preferred vermiculite contains particles that are 4 mm in size with a density of 72-90 kg/cu m. This is considered class 2 pursuant to System A and medium grade or 3, pursuant to System B. It is also acceptable to use vermiculite that contains particles that are 2 mm in size with a density of 75-112 kg/cu m. This vermiculite is considered class 3 pursuant to System A and fine grade or 2 pursuant to System B. An equal substitute for exfoliated vermiculite may be used but should not exceed a bulk density of seven pounds per cubic foot. The rebar support apparatus 1 may be various shapes, however, the most beneficial shape anticipated by this invention is triangular as shown in the sectional view of
The rebar support apparatus 1 of the preferred composition of one and a half part course sand, one part Portland cement, one part vermiculite, such as zoelite or perlite, and approximately two-thirds (⅔) part water. It is understood that the water content varies depending upon the moisture content of the starting ingredients and the humidity of the environment. This cement mixture exhibits superior properties when compared to other formulas. In a test comparing various compositions, the preferred composition provided the highest break point. The test involved three samples of concrete cubes which were submitted to increasing loads to determine the compressive strength of the composition before type 1 failure. The cubes were each about 4.2 to 4.4 square inches in area. The test was collected and reported in general accordance with ASTM C109, C143. The results of the test were as follows.
As shown in the above result table, specimen 1777 resulted in a compressive strength of 2,920 p.s.i. Specimen 1777 was the preferred composition, one and a half part course sand, one part Portland cement, one part vermiculite and about two-thirds (⅔) part water. It should be understood that the rebar support apparatus 1 of the invention could be comprised of various other similar ingredients while still retaining the majority of the desired features. Specimen 1776 was composed of one part Portland cement, one part vermiculite, two parts sand, and five-sixths (⅚) part water. Specimen 1778 was composed of one part Portland cement, one part vermiculite, one and three-fourths (1¾) part sand, and approximately two-thirds (⅔) part water.
Accordingly, it will be understood that the preferred embodiment of the present invention has been disclosed by way of example and that other modifications and alterations may occur to those skilled in the art.
