Anchor Bolt Locator
An anchor bolt locator is provided that is inexpensively manufactured on automatic die-press machines from sheet steel and a structural nut that does not require any welding, while also being easy to use and install with current, commonly-used building practices and anchor designs. The anchor bolt locator is made from a galvanized sheet metal chair and a structural nut attached to the chair by way of a friction fit.
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The present invention relates to a concrete embedded insert, called an anchor bolt locator, for properly locating and supporting a bolt or anchoring member during the pouring and curing of a concrete member, such that bolt will be properly placed in the cured concrete.
A concrete slab member is a common structural element of modern buildings. Horizontal slabs of steel-reinforced concrete are used to construct slab foundations, floors, ceilings, decks and exterior paving.
Concrete slabs are built using formwork - a type of boxing into which the wet concrete is poured. Typically, if the slab is to be reinforced, steel reinforcing rods are used, and these are positioned within the formwork before the concrete is poured. This steel reinforcing is often called rebar. Plastic tipped metal, or plastic bar chairs are typically used to hold the reinforcing rods away from the bottom and sides faces of the formwork, so that when the concrete sets it completely envelops the reinforcing rods. For a slab resting on the ground, the formwork may consist only of sidewalls pushed into the ground. For a suspended slab, the formwork is shaped like a tray, often supported by a temporary scaffold until the concrete sets. The formwork is commonly built from wooden planks and boards, plastic, or steel. After the concrete has set the formwork can be removed or remain in place. In some cases formwork is not necessary - for instance, a ground slab surrounded by brick or block foundation walls, where the walls act as the sides of the tray and the hardcore earth acts as the base.
Concrete slab members are also typically built in a manner that allows for anchor members and fasteners to be built into the slab so that other building elements can be easily and securely anchored to the concrete member. It is very common to see a slab with many different bolts and fasteners protruding from the slab after it has cured and the formwork has been removed. These preset anchors or inserts are typically used for securing pipes or conduits to concrete ceilings, or for securing framing to a concrete foundation or floor.
When anchors such as bolts and threaded rod are to be embedded in a concrete slab, they must be supported during the concrete pour. It is important that the anchors are located properly in the slab and remain undisturbed during the pour, so that subsequent building elements can be attached to them properly. The proper location of anchors in slabs is especially important for decks where the anchor will fasten a safety railing to the deck and for lateral force resisting systems where the anchors must be placed carefully to provide the proper anchorage without interfering with other structural members. Proper location is also important for the integrity of the anchor and the strength of the anchorage. If the anchor is set too close or at an improper angle so that it is too close to the sides of the slab water penetrating into the slab can degrade the anchor, and the strength of the anchorage is also compromised if there is insufficient concrete surrounding the anchor.
Typically, certain of the anchors located in the slab will be located close enough to the edges of the slab that they can be supported by a member attached to the side formwork during the pour. Other anchors will be located sufficiently far away from the sides of the form that they must be supported in some other manner. Sometimes the anchors can be tied to and supported by the reinforcing rods. Other times it is preferable to support the anchor on the underlying surface of the formwork. The present invention is a free-standing anchor bolt locator that attaches to the underlying formwork and holds an anchor or bolt during the concrete pour. Many such devices appear in the patent literature, including: U.S. Pat. No. 5,957,644, granted Sep. 28, 1999, to James A. Vaughan, U.S. Pat. No. 5,050,364, granted Sep. 24, 1991, to Michael S. Johnson et. al., and U.S. Pat. No. 5,205,690, granted Apr. 27, 1993, to Steven Roth.
The present invention improves upon the prior art by providing an anchor bolt locator that is inexpensively manufactured on automatic die-press machines from sheet steel and a structural nut that does not require any welding, while also being easy to use and install with current, commonly-used building practices and anchor designs.
SUMMARY OF THE INVENTIONIt is an object of the present invention is to provide an anchor bolt locator, and a method for making an anchor bolt locator that is economically efficient to produce. It is also an object of the present invention to provide an anchor bolt locator that is easy to use and install. These objects are achieved by forming the chair of the anchor bolt locator out of sheet metal, and forming the anchor bolt locator in such a way that a structural nut can be permanently attached to the sheet metal chair without having to weld the nut to the chair. In this manner an anchor bolt locator is formed that can receive a piece of threaded rod in the nut in the typical fashion currently used for creating threaded rod anchorages with the nut at the proper height for such an anchorage. This type of anchorage is typical in the industry and uses two structural nuts sandwiching a structural plate washer between them. The structural nut of the present invention is designed to serve as the lower nut for a double-nut and plate washer anchorage. By avoiding welding the nut to the chair the structural integrity of the nut is better preserved, and the process does not need to include a welding station. Welding can crack nuts, especially if they are heat treated.
It is also an object of the present invention to provide an anchor bolt locator where the connection between the threaded rod and the locator is easily made. This object is achieved by providing a central opening in the anchor bolt chair that allows the user to precisely position the anchor bolt locator, while also providing tongues that serve as stop to prevent the anchor from being inserted too far into the structural nut. The threaded rod is rotated into the nut and tongues or prongs stop the threaded rod from being inserted farther than is necessary into the nut. If the anchor is threaded too far into the nut, the bottom of the anchor may be placed too close to the bottom of the concrete form which can lead to degradation of the anchor, and it will also mean that less of the anchor protrudes from the top of the form for attaching other devices.
As shown in
As shown in FIGS. 1E and 2D-2F, the bridge 4 is formed with a depression 8 that receives the structural nut 3. The structural nut 3 is connected to the bridge 4 by frictional engagement and is held securely in place. The inner surface 9 of the side wall 10 of the depression 8 in the bridge 4 frictionally engages with the outer surface 11 of the outer side wall 12 of the nut 3. Preferably, the outer side surface 11 of the nut 3 is made with flat faces 13 to have a polygonal, preferably hexagonal, cross-section. As shown in
As shown in
As shown in
Since the anchor bolt locator 1 is preferably made from thin sheet steel the bridge 4 and legs 5 and 6 are, preferably, generally planar, thin members. See
As shown in
As shown in
Mounting holes 27 are provided in the bridge 4, preferably at all four corners of the bridge 4. As shown in
The anchor bolt locator 1 is preferably formed from galvanized, stainless-steel formed in a sheet. Steel is sufficiently rigid, and can be cold-formed to grip the structural nut 3 after it has been placed in the depression 8. In the preferred method of making the anchor bolt locator 1, any openings that are to be made in the bridge 4 are formed first, usually with or right after the blank for the chair 2 is cut from the sheet stock. See
As shown in
Claims
1. An anchor bolt locator, comprising:
- a. a chair, having a plurality of legs, a bridge connecting the legs, said bridge having a top surface, with the plurality of legs extending from the bridge in the same direction away from said top surface of said bridge,
- b. a depression formed in the bridge of the chair, the depression having a side wall with an inner surface, the side walls extending away from the top surface of the bridge, the depression also having a bottom floor with a top surface,
- c. a structural nut received in the depression of the bridge, the structural nut having a top end, a bottom end, an internal, threaded bore forming an internal, threaded side wall, said structural nut also having an outer side wall defining an outer surface of said nut, wherein, the bottom end of the structural nut rests on the top surface of the bottom floor of the depression, and portions of the outer surface of the outer side wall of the structural nut are in contact with and in frictional engagement with portions of the inner surface of the side wall of the depression such that the structural nut is secured to the chair.
2. The anchor bolt locator of claim 1, wherein:
- the depression is formed with an opening in the bottom floor.
3. The anchor bolt locator of claim 1, wherein:
- the opening in the bottom floor of the depression is located in the center of the depression.
4. The anchor bolt locator of claim 1, wherein:
- the bottom floor of the depression is made from one or more tongues that extend inwardly from the side wall.
5. The anchor bolt locator of claim 4, wherein:
- one or more of said one or more tongues extends inwardly past the internal side wall of the internal bore of the structural nut.
6. The anchor bolt locator of claim 1, wherein:
- edge openings are formed in the side wall of the depression.
7. The anchor bolt locator of claim 1, wherein:
- a portion of said bridge surrounding said depression in said bridge of said chair is a substantially planar and relatively thin member.
8. The anchor bolt location of claim 7, wherein:
- said structural nut between said top end and said bottom end has a thickness that is substantially greater than said relatively thin portion of said bridge surrounding said depression.
9. The anchor bolt locator of claim 7, wherein:
- said depression in said bridge has a depth from said top surface of said bridge to said bottom floor of said depression with portions of said side wall of said depression extending from said top surface of said bridge to said bottom floor of said depression and said depth of said depression is substantially greater than said relatively thin portion of said bridge surrounding said depression.
10. A method of making an anchor bolt locator, comprising:
- a. cutting a planar blank for a chair from a sheet of steel;
- b. bending said blank for said chair, so that a bridge is formed connecting downwardly depending legs on either side of said bridge, said legs extending away from a top surface of said bridge;
- c. forming a depression in said bridge, the depression having a side wall with an inner surface, the side walls extending away from the top surface of the bridge, the depression also having a bottom floor with a top surface;
- d. forming one or more embossments in the bridge in one or more portions of the bridge near the depression;
- e. placing a structural nut in the depression of the bridge, the structural nut having a top end, a bottom end, an internal bore forming an internal side wall, said structural nut also having an outer side wall defining an outer surface of said nut, such that the bottom end of the structural nut rests on the top surface of the bottom floor of the depression, and portions of the outer surface of the outer side wall of the structural nut is in alignment and in close proximity to portions of the inner surface of the side wall of the depression;
- f. following the placement of the structural nut in the depression in the bridge, pressing the embossments in the bridge in one or more portions of the bridge near the depression towards the original planar position of the bridge such that the metal that makes the embossments flows toward the depression and portions of the side wall of the depression are pressed against the outer side wall of the nut, creating a friction fit that secures the structural nut to the chair.
11. The method of claim 10, wherein:
- an opening is formed in the depression of the bridge before the structural nut is placed in the depression of the bridge.
12. The method of claim 11, wherein:
- mounting openings are formed in the bridge.
13. The anchor bolt locator of claim 1, wherein:
- said outer side surface of the nut is made with flat faces to have a polygonal cross-section.
Type: Application
Filed: Feb 25, 2013
Publication Date: Jan 2, 2014
Applicant: Simpson Strong-Tie Company, Inc. (Pleasanton, CA)
Inventors: Jin-Jie Lin (Livermore, CA), Timothy S. Ellis (Thousand Oaks, CA)
Application Number: 13/776,349
International Classification: E04B 1/41 (20060101);