US20070157541A1

US20070157541A1 - Wire rebar chair

Info

Publication number: US20070157541A1
Application number: US11/329,570
Authority: US
Inventors: Niels Mossbeck; Darrell Richmond
Original assignee: L&P Property Management Co
Current assignee: L&P Property Management Co
Priority date: 2006-01-11
Filing date: 2006-01-11
Publication date: 2007-07-12

Abstract

A unitary wire chair is disclosed for supporting concrete reinforcing rebar or the like above a supporting surface onto which concrete is poured. The unitary wire chair is so constructed such that it may be snapped or otherwise secured onto the rebar or other concrete reinforcing element and retained thereon without the use of any tie wire or other attachment devices.

Description

TECHNICAL FIELD

The present invention relates to spacers, or so-called chairs, that are used in construction for the support of rebar, post-tension cables or wire mesh. More particularly, the present invention relates to chairs made of wire that are used for the support of rebar, post-tension cables, or wire mesh in poured concrete.

BACKGROUND OF THE INVENTION

Spacers, or so-called chairs, are commonly used in the concrete construction industry for the support of rebar or post-tension cables or mesh above a surface onto which concrete is to be poured. Typically, rebar, cable or mesh, when used to reinforce concrete, must be supported above the surface onto which the concrete is poured. Chairs are generally used with poured concrete decks, pre-cast work, and bridges, roads or so-called slab-on-grade applications. In use, a rebar supporting surface on the chair supports the rebar while the base of the chair rests on the deck or surface to which the concrete is to be applied. When the concrete is poured, the chair maintains the cable or rebar a proper distance above the supporting surface.
Currently, one of the most popular chairs used to support rebar is made from a pair of bent wires. A first bent wire is generally in the shape of an inverted U and has a recessed surface in the cross bar at the top onto which the rebar is located. The sides of the U-shaped wire support the recessed cross bar in an upright condition above the supporting surface. A second wire is formed as an inverted U and is welded to the bottom edge of the cross bar of the first wire and extends at 90° to that cross bar. The second wire also has vertically extending legs which support the second wire above the supporting surface. Generally, to prevent the rebar supported from this type of wire chair during pouring of the concrete, the rebar is tied to the supporting surface of the chair by a tie wire.
One problem with this type of wire chair is that it is relatively expensive to manufacture because of the welding required in the course of its manufacture, but also because it requires substantial hand labor to manually attach the rebar to the chair by means of tie wires. It has therefore been an objective of this invention to provide a wire chair which is less costly to manufacture and which eliminates the need for tie wires to attach the wire chair to the rebar.
There have been rebar supporting chairs manufactured which do not require the use of tie wires for attachment of the chair to the rebar. For example, as disclosed in U.S. Pat. No. 5,893,252, there are chairs which may be snap-fit onto the rebar so as to support that rebar above a supporting surface, but such snap-on-type of rebar supporting chairs have generally been made of plastic and are substantially more expensive and difficult to manufacture than wire rebar supporting chairs. It has therefore been another objective of this invention to provide a wire rebar supporting chair which may be snapped onto a rebar and frictionally held thereon without the need for tie wires or a complex plastic snap-fit connection.

SUMMARY OF THE INVENTION

The wire rebar chairs of this invention are formed from a single unitary wire which supports a concrete reinforcing rebar or the like and which are so constructed that they may be snapped onto or otherwise secured onto the rebar or other concrete reinforcing element and retained thereon without the use of tie wires or other attachment devices. To that end, one embodiment of the invention comprises three parallel cross bars, a central one of which is adapted to be received atop a rebar and the other two parallel cross bars of which are adapted to be received on the underside of the rebar with connecting bars connected to opposite ends of the central one of the three parallel cross bars and riser bars extending downwardly away from the ends of each of the other two parallel cross bars, which riser bars terminate in a supporting foot. The supporting foot is intended to rest upon the supporting surface while concrete is poured onto that supporting surface. Preferably, this wire chair is heat-treated after formation of the chair so as to impart spring-like qualities to the wire chair, such that when secured onto a rebar, the spring-like qualities retain the wire chair on the rebar against any forces which it might otherwise tend to displace it.
Another embodiment of the invention comprises a single unitary wire formed as two riser bars extending upwardly from opposite ends of a support foot section of wire. The two upwardly extending riser bars terminate in generally U-shaped loops which snap over and onto opposite sides of a rebar or like concrete reinforcing wire.
In yet another embodiment of the invention, a single unitary wire has a straight upper horizontal bar section from the opposite ends of which are formed generally U-shaped loops which snap over a rebar or rebar-like concrete reinforcing wire. At the end of the loops opposite the straight horizontal bar section, riser bars extend generally downwardly to supporting foot sections of wire.
As a still further modification of the embodiment described immediately hereinabove, the generally U-shaped loops are connected to a generally V-shaped nose section of the chair wire rather than a straight upper bar section of the unitary wire.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other variations and embodiments of this invention will be more readily apparent from the following description of the drawings, in which:
FIG. 1 is a perspective view of one embodiment of the wire chair of this invention supporting a rebar shown in phantom;
FIG. 2 is a perspective view of multiple chairs supporting a rebar above a supporting surface;
FIG. 3 is a side elevational view of the wire chair of FIG. 1 supporting a rebar;
FIG. 4 is a top plan view of the wire chair of FIG. 1, the rebar being shown in phantom;
FIG. 5 is a perspective view illustrating how the wire chair of FIGS. 1-4 is applied to the rebar;
FIG. 6 is a perspective view of a modified form of chair incorporating the invention of this application; and
FIGS. 7, 8 and 9 are perspective views of three further embodiments of the invention of this application.

DETAILED DESCRIPTION OF THE INVENTION

With reference first to FIG. 1, there is illustrated a concrete reinforcing element of rebar 10 and a rebar chair 12 made of one piece of wire 5 for supporting that rebar 10 a predetermined distance above a support surface 14 (see FIG. 2). The chair 12 comprises three parallel cross bars 16, 18 and 20, the centermost one, 18, of which is connected to the other two 16 and 20 via connector bars 22 and 24. As may be seen most clearly in FIG. 3, the centermost one of these three cross bars 18 is located atop the rebar 10 and the two other cross bars 16 and 18 are located on the underside of the rebar 10. At its opposite ends, the centermost cross bar 18 is connected to the cross bars 16 and 20 by connector bars 22, 24 which extend downwardly and outwardly from opposite ends of the uppermost cross bar 18. Ninety degree (90°) bends 26, 28 in the wire connect the opposite ends of the cross bar 18 to the connector bars 22 and 24, respectively. See FIG. 4. Similarly, another ninety degree (90°) bend in the wire 5 connects each of the connecting bars 22, 24 to cross bars 16 and 20, respectively. See FIG. 4.
The ends of the outermost cross bars 16 and 20 opposite the end connected to the connector bars 22 and 24 is connected via ninety degree (90°) bends 34, 36, respectively, to riser bars 40, 42. The riser bars 40, 42 extend downwardly and outwardly away from the cross bars to which they are connected and terminate in supporting feet 44, 46. Each supporting foot 44, 46 is connected to the lower end of the riser bars 40, 42, respectively, by ninety degree (90°) bends 48 and 50, in the wire, respectively. See FIG. 4.
In the embodiment of the invention illustrated in FIGS. 1-4, each of the cross bars 16, 18 and 20, as well as each connector bars 22 and 24, and each riser bar 40, 42 is a linear straight bar connected to its next adjacent bar by a ninety degree (90°) bend in the wire 5. So constructed, this embodiment of wire chair 12 may be easily formed on a conventional wire bending machine.
As may be seen most clearly in FIG. 3, when the chair 12 is placed over a rebar 10 or other concrete reinforcing element, the cross bars 16, 18 and 20, as well as the supporting feet 44 and 46 are all located in a horizontal plane with the supporting feet 44 and 46 intended to be resting upon the support surface 14 over which concrete is to be poured to encase the rebar or concrete reinforcing element in the concrete. In the embodiment here illustrated, the connecting bars 22 and 24 extend downwardly and outwardly from the horizontally extending cross bar 18 at an angle a approximately thirty degrees (30°) to a vertical plane 52 through the cross bar 18. And in the preferred embodiment, the riser bars 40, 42 extend downwardly and outwardly from the horizontal cross bars 16 and 20 at an angle β at approximately thirty degrees (30°) to a vertical plane 54 through the cross bars 16 and 20, respectively.
In order to accommodate the chair to differing applications, the angles α and β may vary, as well as the length of the riser bars and connector bars. For example, if a smaller rebar or concrete reinforcing wire or element is utilized, the connector bars 22 and 24 will be shortened and/or the angle a increased to as to accommodate the smaller diameter rebar or wire. And similarly, if the rebar or concrete reinforcing element is to be increased in elevation relative to the supporting surface 14, the length of the riser bars 40 and 42 would be increased and/or the angle β decreased to accomplish the increased elevation of the supported rebar or reinforcing element.
In one preferred embodiment of this invention, after formation of the chair 12, the chair is preferably subjected to a heat treatment so as to improve and increase the formed stability of the formed chair. One suitable heat treatment involves subjecting the formed chair to a temperature of 450 to 550° F. and then cooling the chair to room temperature so as to result in its having spring-like resilient qualities. Not only does this heat treatment increase the forms or shaped stability of the chair, but it better enables the chair to grip a rebar 10 inserted into the gaps 56, 58 between the cross bars 16, 18, 20 as explained more fully hereinafter.
With reference now to FIG. 5, it will be seen that in order to attach a chair 12 to a rebar 10, all that is required is for the chair 12 to be moved into a position relative to the rebar 10 in which the rebar is located within one of the pockets or gaps 56, 58. Pocket 56 is defined between cross bars 18 and 20. Pocket 58 is defined between cross bars 18 and 16. See FIG. 4. Thereafter, the chair 12 may be rotated ninety degrees (90°) so as to position the rebar 10 within the other of the two pockets 56, 58. See FIG. 5. When so positioned, the centermost cross bar 18 is located atop the rebar 10 and the other two cross bars 16 and 20 are located on the underside of the rebar 10. Preferably, the connector bars 22 and 24 are of such a length and the angles a are such that in the course of rotating the chair ninety degrees (90°) so as to position the rebar 10 within the two pockets 56 and 58, the cross bars 16 and 20 are forced outwardly away from the centermost cross bar 18 so as to securely lock the rebar 10 within these pockets 56, 58.
With reference now to FIG. 6, there is illustrated another embodiment of this invention. This embodiment of wire chair 12′ is identical to the embodiment of FIGS. 1-5 except that the connector bars 22′ and 24′ are semicircular rather than straight bars. There are bending machines which will accommodate this configuration of wire bending without the need for ninety degree (90°) bends between the cross bars and connecting bars as in the embodiment of FIGS. 1-5.
In the embodiment of FIG. 6, there may be detents (not shown) formed in the cross bars 18, 16 and 20, respectively, so as to better enable the rebar 10 supported by the chair to be locked into the pockets 56, 58 of the chair. The detents will assist in preventing the chairs from being inadvertently knocked off of the rebar in the event that the force of the poured concrete contacting the chair tends to dislocate it, or in the event that workmen working in connection with the rebar step over or on it and tend to displace it.
With reference now to FIG. 7, there is illustrated another embodiment of a wire chair incorporating the invention of this application. This chair 60 comprises a unitary wire, the center portion of which comprises a straight horizontal bar section 62 at the opposite ends of which there are formed generally U-shaped loops 64, 66 which are so sized as to be snapped over a rebar 68 or similar concrete reinforcing wire or rod. These loops 64, 66 terminate in a generally vertically extending riser bar 70, 72 at the end of each of which there is a horizontal extending supporting foot 74, 76. These supporting feet, 74, 76, support the chair 60 upon the surface to which concrete is to be applied after the rebar or concrete reinforcing wire or bar 68 is snap-fit into the loops 64, 66 of the chair 60.
With reference now to FIG. 8, there is illustrated yet another embodiment of a chair incorporating the invention of this application. This chair 80 is very similar to the chair 60 of FIG. 7 except that instead of the generally horizontally extending straight bar 62, the generally U-shaped loops 84, 86, which are intended to be snap-fit over a rebar 68 or concrete reinforcing wire or rod, are connected to a generally V-shaped nose piece 82. The opposite ends of this V-shaped nose piece 82 terminate in the loops 84, 86 within which the rebar 68 is received. The lower ends of these loops 84, 86 are connected to riser sections 88, 90 of the chair 80 which in turn are connected to supporting feet 92, 94. In use, the feet 92, 94 rest upon the supporting surface to which concrete is to be applied while the chair supports the rebar or concrete reinforcing rod or wire above that supporting surface.
With reference now to FIG. 9, there is illustrated yet another embodiment of a unitary wire chair incorporating the invention of this application. This chair 100 comprises a generally Z-shaped supporting foot 102 which forms the center portion of the wire chair. Riser bars 104, 106 extend upwardly from opposite ends of this Z-shaped generally supporting foot 102. These riser bars 104, 106 terminate in generally U-shaped loops 108, 110 at the upper ends of the riser bars 104, 106, respectively. In use of this chair 100, the rebar 68 or concrete reinforcing rod wire 68 is inserted into the loops 108, 110, one of which is located on one side of the rebar or rod, and the other of which is located on the opposite side. The rebar 68 is snap-fit into these loops 108, 110, after which the rebar is firmly held by the chair 100 against movement or displacement of the chair 100 during pouring of the concrete.
It will readily be apparent to persons skilled in the art that while we have described several embodiments of our invention, other changes and modifications may be made without departing from the spirit of our invention. Therefore, we do not intend it to be limited except by the scope of the following appended claims.

Claims

1. A unitary wire chair for supporting concrete reinforcing rebar or the like above a supporting surface while concrete is poured onto that supporting surface, which chair comprises:

at least three parallel cross bars connected by two connecting bars, a central one of said three parallel cross bars being adapted to be received atop a rebar and the other two parallel cross bars being adapted to be received on the underside of said rebar; and

riser bars extending downwardly away from an end of each of said other two parallel cross bars.

2. The unitary wire chair of claim 1 wherein said two connecting bars are connected to opposite ends of said central one of said three parallel cross bars.

3. The unitary wire chair of claim 1 wherein each of said riser bars is connected at its lower end to a supporting foot.

4. The unitary wire chair of claim 3 wherein each supporting foot comprises a linear bar which extends parallel to said three parallel cross bars.

5. The unitary wire chair of claim 1 wherein said chair is adapted to be secured onto a rebar by locating the rebar between two of said three parallel cross bars and then rotating said chair 90° to lock said chair onto said rebar.

6. The unitary wire chair of claim 1 wherein said chair is subjected to heat treatment after formation of said chair.

7. The unitary wire chair of claim 6 wherein said heat treatment comprises heating said chair to a temperature of between 450° to 550° F. and then cooling said chair to impart improved form stability to said chair.

8. A unitary wire chair for supporting a concrete reinforcement element above a supporting surface while concrete is poured onto that supporting surface, which chair comprises:

at least three parallel cross bars connected by two connecting bars, a central one of said three parallel cross bars being adapted to be received atop a reinforcement element and the other two parallel cross bars being adapted to be received on the underside of said reinforcement element; and

9. The unitary wire chair of claim 8 wherein said two connecting bars are connected to opposite ends of said central one of said three parallel cross bars.

10. The unitary wire chair of claim 8 wherein each of said riser bars is connected at its lower end to a supporting foot.

11. The unitary wire chair of claim 10 wherein each supporting foot comprises a linear bar which extends parallel to said three parallel cross bars.

12. The unitary wire chair of claim 8 wherein said chair is adapted to be secured onto a reinforcement element by locating the reinforcement element between two of said three parallel cross bars and then rotating said chair 90° to lock said chair onto said reinforcement element.

13. The unitary wire chair of claim 8 wherein said chair is subjected to heat treatment after formation of said chair.

14. The unitary wire chair of claim 13 wherein said heat treatment comprises heating said chair to a temperature of between 450° to 550° F. and then cooling said chair to impart improved form stability to said chair.

15. A unitary wire chair for supporting a concrete reinforcing element above a supporting surface, which chair comprises:

at least three parallel cross bars connected by at least two connecting bars, at least one of said parallel cross bars being adapted to be received atop a reinforcing element and at least two parallel cross bars being adapted to be received on the underside of said reinforcing element; and

riser bars extending downwardly away from an end of at least two of said parallel cross bars.

16. The unitary wire chair of claim 15 wherein each of said riser bars is connected at its lower end to a supporting foot.

17. The unitary wire chair of claim 16 wherein each supporting foot comprises a linear bar which extends parallel to said three parallel cross bars.

18. A unitary wire chair for supporting concrete reinforcing element above a supporting surface while concrete is poured onto that supporting surface, which chair comprises:

at least three parallel cross bars connected by two connecting bars, a central one of said three parallel cross bars being adapted to be received atop a concrete reinforcing element and the other two of said three parallel cross bars being adapted to be received on the underside of said concrete reinforcing element, said two connecting bars being connected to opposite ends of said central one of said three parallel cross bars; and

a pair of riser bars extending downwardly away from an end of each of said other two parallel cross bars.

19. The unitary wire chair of claim 18 wherein each of said riser bars is connected at its lower end to a supporting foot.

20. A unitary wire chair for supporting concrete reinforcing rebar or the like above a supporting surface while concrete is poured onto that supporting surface, which chair comprises:

at least three parallel cross bars connected by two connecting bars, said two connecting bars being connected to opposite ends of a central one of said three parallel cross bars; and

a riser bar extending downwardly away from an end of each of said other two parallel cross bars.

21. The unitary wire chair of claim 20 wherein each of said riser bars is connected at its lower end to a supporting foot.

22. The unitary wire chair of claim 21 wherein each supporting foot comprises a linear bar which extends parallel to said three parallel cross bars.

23. The unitary wire chair of claim 21 wherein said chair is adapted to be secured onto a rebar or the like by locating the rebar between two of said three parallel cross bars and then rotating said chair 90° to lock said chair onto said rebar or the like.

24. A unitary wire chair for supporting concrete reinforcing rebar or the like above a supporting surface, which chair comprises:

a central section of said wire having generally U-shaped loops formed at its opposite ends, each of said loops terminating in a generally vertically extending riser bar; and

a supporting foot formed on an end of each riser bar.

25. The unitary wire chair of claim 24 wherein said central section of wire is a straight linear section of wire.

26. The unitary wire chair of claim 24 wherein said central section of wire is generally V-shaped.

27. A unitary wire chair for supporting concrete reinforcing rebar or the like above a supporting surface, which chair comprises:

a lower central foot supporting section;

riser bars extending upwardly from said lower central foot section;

generally U-shaped loops formed on the upper ends of each of said riser bars, said loops being adapted to be snap-fit onto a rebar or other type of concrete reinforcing wire or rod.

28. A unitary wire chair for supporting concrete reinforcing rebar or the like, said chair being formed from a single length of wire having at least one portion of the wire so configured that it may be snap-fit onto a rebar or the like and retained thereon without any other attachment device.

29. The unitary wire chair of claim 28 wherein said chair comprises riser bars which support said snap-fit portion spaced from at least one supporting foot portion of said chair.