WELDLESS REBAR CHAIRS

Abstract

A form for creating a weldless rebar chair has an elongate rod arranged along a predetermined direction, said rod being formed into at least a plurality of partial elongate loops spaced from each other along the predetermined direction and arranged in a common plane defined by the elongate rod and the elongate loops. A method of producing a weldless rebar chair comprising the steps of arranging an elongate rod along the predetermined direction and bending it to create the elongate loops spaced and bending the loops at transition points to form intermediate portions arranged in a common plane and free ends that extend in directions normal to the plane, alternate free ends being bent in opposite directions and having lengths that are substantially equal to provide legs that can be placed on a surface to stabilize the rebar chairs.

Claims

1. A form for creating a weld-less rebar chair comprising a continuous elongate rod arranged along a predetermined direction, said rod being formed into at least a plurality of loops extending substantially equal distances in a common direction normal to said predetermined direction spaced from each other along said predetermined direction and arranged in a common plane defined by said elongate rod and said elongate loops.

2. A form as defined in claim 1, wherein said loops are elongate loops.

3. A form as defined in claim 1, wherein said loops are open loops.

4. A form as defined in claim 1, wherein said loops are closed loops.

5. A form as defined in claim 1, wherein said elongate rod is made of ASTM A1035 CS Grade 100 steel.

6. A form as defined in claim 1, wherein said elongate rod is made of ASTM A1035 CS Grade 120 steel.

7. A form as defined in claim 1, wherein said elongate rod is made of steel that achieves yield strength between 100 and 120 Ksi of the ASTM A1035 specification while maintaining ductility and tensile-to-yield ratio above 1.25.

8. A weld-less rebar chair comprising an elongate rod arranged along a predetermined direction, said rod being formed into at least a plurality of loops extending substantially equal distances in a common direction normal to said predetermined direction spaced from each other along said predetermined direction, said loops having free ends and intermediate portions between said free ends and said elongate rod, said intermediate portions being arranged in a common plane defined by said elongate rod and said intermediate portions and said free ends being bent out of said common plane in directions generally normal to said intermediate portions, alternate free ends being bent in opposite orthogonal directions in relation to said common plane, said intermediate portions having lengths within said common plane that are substantially equal to provide legs that can be placed on a surface to stabilize the rebar chair.

9. A weld-less rebar chair as defined in claim 8, wherein said loops are elongate loops.

10. A weld-less rebar chair as defined in claim 8, wherein said loops are open loops.

11. A weld-less rebar chair as defined in claim 8, wherein said loops are closed loops.

12. A weld-less rebar chair as defined in claim 8, wherein said elongate rod is made of ASTM A1035 CS Grade 100 steel.

13. A weld-less rebar chair as defined in claim 8, wherein said elongate rod is made of ASTM A1035 CS Grade 120 steel.

14. A weld-less rebar chair as defined in claim 8, wherein said elongate rod is made of steel that achieves yield strength between 100 and 120 Ksi of the ASTM A1035 specification while maintaining ductility and tensile-to-yield ratio above 1.25.

15. A method of producing a form for creating a weld-less rebar chair comprising the steps of selecting a length of an elongate continuous rod and arranging it along a predetermined direction; bending said rod to create a plurality of loops extending substantially equal distances in a common direction normal to said predetermined direction spaced from each other along said predetermined direction in a common plane defined by said elongate rod and said elongate loops.

16. A method as defined in claim 15, wherein said loops are open loops.

17. A method as defined in claim 15, wherein said loops are closed loops.

18. A method as defined in claim 15, wherein said elongate rod is made of ASTM A1035 CS Grade 100 steel.

19. A method as defined in claim 15, wherein said elongate rod is made of ASTM A1035 CS Grade 120 steel.

20. A method as defined in claim 15, wherein said elongate rod is made of steel that achieves yield strength between 100 and 120 Ksi of the ASTM A1035 specification while maintaining ductility and tensile-to-yield ratio above 1.25.

21. A method of producing a weld-less rebar chair comprising the steps of selecting a length of an elongate continuous rod and arranging it along a predetermined direction; bending said rod to create at least a plurality of loops extending substantially equal distances in a common direction normal to said predetermined direction spaced from each other along said predetermined direction, bending said loops at transition points to form intermediate portions arranged in a common plane defined by said elongate rod and said intermediate portions and free ends that extend out of said common plane in directions generally normal to said intermediate portions, alternate free ends being bent in opposite orthogonal directions in relation to said common plane, said intermediate portions having lengths within said common plane that are substantially equal to provide legs that can be placed on a surface to stabilize the rebar chairs.

22. A weld-less rebar chair comprising an elongate rod arranged along a predetermined direction and defining an axis, said rod being formed into at least a plurality of loops extending substantially equal distances in a direction normal to said predetermined direction spaced from each other along said predetermined direction, alternate loops being angularly offset relative to a plane passing through said axis and each forming angles with said plane less than 90.

23. A method of producing a weld-less rebar chair comprising the steps of selecting a length of an elongate continuous rod and arranging it along a predetermined direction and defining an axis; bending said rod to create at least a plurality of loops extending substantially equal distances in a direction normal to said predetermined direction spaced from each other along said predetermined direction; and angularly offsetting alternate loops about said axis to opposite sides of a plane passing through said axis and each forming angles with said plane less than 90.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Those skilled in the art will appreciate the improvements and advantages that derive from the present invention upon reading the following detailed description, claims, and drawings, in which:

[0017] FIG. 1 is a side elevational view of a form for creating a weldless rebar spacer or chair that includes a plurality spaced closed loops that project within a common plane in a direction away from the rod;

[0018] FIG. 2 is a side elevational view of a form for creating a weldless rebar spacer or chair that includes a plurality spaced open loops that project within a common plane in a direction away from the rod;

[0019] FIG. 3 is a side elevational view of a rebar spacer or chair formed from the form shown in FIG. 1;

[0020] FIG. 4 is a top plan view of the rebar spacer or chair shown in FIG. 3;

[0021] FIG. 5 is similar to FIG. 3 but showing a rebar spacer or chair made with the form shown in FIG. 2;

[0022] FIG. 6 is a top plan view of the rebar spacer or chair shown in FIG. 5;

[0023] FIG. 7 is a perspective view of three different spacers or chairs created from the open loop form shown in FIG. 2 wherein the intermediate portions are varied to change the heights of the rebar-supporting rods;

[0024] FIG. 8 is a perspective view showing two different height rebar spacers or chairs of the type shown in FIG. 7 for supporting reinforcing bars or rebars at two different heights or levels prior to pouring of concrete;

[0025] FIG. 9 is a top plan view of the spacers or chairs and attached rebars as shown in FIG. 8;

[0026] FIG. 10 is an end elevational view of an alternate configuration of a rebar chair; and

[0027] FIG. 11 is similar to FIG. 10 showing a modified form of the alternate configuration that raises the height of the chair for rebars.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0028] Referring now specifically to the Figures, in which identical or similar parts are designated by the same reference numerals throughout, and first referring to FIG. 1, a form for producing rebar spacers or chairs is designated by the reference numeral 10 comprises an elongate rod 12 that defines a predetermined direction, along axis A, the rod being formed with a plurality of at least partial elongate loops 14, generally uniformly spaced from each other as shown along the axis A. The rod 12 and the elongate loops 14 define a common plane (the plane of FIG. 1). The loops 14 in the form 10 are generally closed loops as shown. In the illustrated configuration the loops are spaced a distance S along the axis A. The widths of the individual loops 14 are designated by the dimension s although neither the dimensions S nor s is critical for the purposes of the present invention. These may be selected to meet specific requirements on a particular project, conform to required cost loads.

[0029] Further described in connection with FIGS. 3 and 4 the form 10 can be formed into rebar chairs or spacers by only using bending equipment. This requires that the bar or rod 12 is not only sufficiently strong to support the rebars but also must be ductile to allow bending or deformation of the steel to create the loops without undue effort or cost. This has been difficult if not impossible to do with stainless steel or other steels that are generally corrosion resistant. ChromX 9000 Series steels marketed by MMFX Technology Corp., of Irvine Calif. is an ideal material for use in connection with the rebar spacers or chairs in accordance with the invention. The use of ChromX 9000 Series steels, including 9100 (ASTM A1035 CS Grade 100 Steel) and 9120 (ASTM A1035 CS Grade 120 Steel) steels, with the subject invention save construction time and labor. The product's corrosion protection extends the service life and reduces the life cycle cost for concrete structures even in highly corrosive environments. Its uncoated corrosion protection means no additional costs from special handling, coating, inspection and repair. The aforementioned MMFX steels are more fully disclosed in U.S. Pat. No. 4,671,827 issued on Jun. 9, 1987 to Thomas et al., for Method of Forming High-Strength, Tough, Corrosion-Resistant Steel. Additional patents that have been issued relating to MMFX Steel that describes such corrosion resistance steel products include: U.S. Pat. Nos. 4,170,499; 4,619,714; 6,273,968; 6,709,534; 7,118,637; 6,746,548; 6,827,797; and 7,214,27.

[0030] The rod 12 can be bent by conventional machinery. The rods can be formed as shown in FIG. 1 either in predetermined or fixed lengths or be continuous. Referring to FIG. 3 and 4, the advantages of the weldless method of creating rebar spacers or chairs will become immediately appreciated. The closed loops 14 shown in FIG. 1 have free ends 14a and intermediate portions 14b between the free ends 14a and the elongate steel rod 12. The intermediate portions 14b are arranged in a common plane, in the plane of the drawing, with the elongate rod 12 and the intermediate portion and the free ends 14a being bent out of the common plane in a direction generally normal to the intermediate portions. In order to form the spacers or chairs alternate free ends 14a are bent in opposite orthogonal directions in relation to the common plane. The intermediate portions 14b have lengths within the common plane which are substantially equal to provide legs 22 that can be placed on a surface to stabilize the rebar spacers or chairs.

[0031] The specific configurations of the loops that are formed from the rod 12 are not critical. What is important is that the loops extend from the rod along a direction A.sub.T so that the loops can define a transition point 14c that separates the free ends 14a and the intermediate portions 14b. In FIGS. 1, 3 and 4 the loops are shown to be closed loops. In FIGS. 2, 5 and 6 the loops are shown as open loops 16. Either one can be used with different degrees of advantage. In both configurations, the loops extend along a transverse direction A.sub.T to the axis A and have a total length L. The free ends have a length m while the intermediate portions have a length equal to l so that L=l+m. In forming a spacer or chair from either one of the forms shown in FIGS. 1 and 2, the loops 14, 16 are bent at the transition points 14c , 16c respectively to form intermediate portions 14b, 16b arranged in the common plane defined by the elongate rods 12 and the intermediate portions while the free ends 14a, 16a respectively extend out of the common plane in directions generally normal to the intermediate portions as shown. Alternate free ends are bent in opposite orthogonal directions in relation to the common plane so that the intermediate portions have substantially equal lengths l within the common plane to provide similarly dimensioned legs 22 that can be placed on a surface to stabilize the rebar space or chair.

[0032] Referring to FIG. 7, three different configurations 20, 20, 20 of the open loop rebar spacer or chair of the type shown in FIGS. 2, 5 and 6 are shown. Each of these was initially formed from the same open loop form 10 each having loops with the same longitunal length L. The spacer or chair 20 was formed by bending the open loop 16 to provide an intermediate portion 16b that generally raises the height of the rod 12 above the support surface at the same time generally decreasing the length of the free end 16a. The intermediate spacer or chair 20 shown in FIG. 7 is formed to lower the height of the rod 12 by decreasing the height of the intermediate portion 16b, thereby increasing the length of the free end 16a. As indicated, the total lengths the free ends and the intermediate portions will be equal to the initial overall length L of the loops. Similarly, the spacer or chair 20 is similar to the other chairs 20, 20 except that now the rod 12 has been lowered still further by decreasing the dimension of 16b while, as before, the length of the free end 16a increases. Clearly, the lengths of the free ends 16a, 16a and 16a is not critical and can be any dimension. The only critical dimension is the heights of the intermediate portions which can be customized to accommodate any given height requirement without considering the otherwise needed dimensions or heights. Referring to FIGS. 8 and 9, there is illustrated the means for supporting two levels of reinforcement bars or rebars at two different heights, using the lowest height spacer or chair 20 shown in FIG. 7 and the higher height spacer or chair 20. The lower rebars are designated by the reference numeral 24 while the higher rebars are designated by the reference numeral 26. Transverse rebars 28 can also be secured to the rebars 24, 26 that rest directly on the spacers or chairs. Conventional ties 30 can be used to secure the rebars to each other or rebars to the chairs or spacers as shown.

[0033] It will be appreciated that the present invention provides tremendous flexibility in the construction trades. Not only is the product superior and can last over a hundred years without corrosion the inventory problem is virtually eliminated or significantly reduced. Whether the loops are closed, open or otherwise a steel of the type under discussion that can be readily bent to provide the desired heights of the spacers or chairs can be made in whatever heights are needed from the same forms by making the dimension L sufficiently large to allow the formation of rebar spacers or chairs with legs determined by the desired or required dimension l. These can provide the full gamut of heights that may be needed at a construction site.

[0034] While the presently preferred embodiments utilize MMFX steels as aforementioned, other steels that have similar properties can also be used, namely high strength, good ductility and corrosion resistant steels. Preferably, the steel should be corrosion resistant for at least one hundred years. Thus, while the initial cost of both the steel and production might be higher than the use of conventional steels such higher initial cost is offset by the extended corrosion resistance so that over the long term the effective costs of installation, construction and repair will be reduced.

[0035] FIGS. 10 and 11 illustrate alternate configurations 32 of a rebar chair that can use the forms 10 or 10. However, instead of bending the loops 14, 16 at transition points 14c. 16c to modify the heights of the chairs alternate loops 14, 16 are angularly offset about the axis A of the rod 12. In. FIG. 10 alternate loops are offset angles .sub.1 and .sub.2 in relation to a vertical plane extending through the axis A of rod 12 to elevate the rod 12 a height h.sub.1. While angles .sub.1, .sub.2 do not need to be identical they are preferably equal or substantially equal. When the height of the chair needs to be increased the loops can be deflected or angularly offset by smaller angles .sub.3, .sub.4 to increase the chair height to h.sub.2. Again the angles .sub.3, .sub.4 are preferably equal or substantially the same.

[0036] All of the embodiments provide a wide range of height adjustability by either shifting the locations of the transition points 14c, 16c along the lengths L of the loops 14, 16 or by changing the angles .sub.1-.sub.4.

[0037] The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.