Abstract:
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.

Description:
BACKGROUND OF THE INVENTION 
     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 INVENTION 
     It 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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a perspective view of the anchor bolt locator of the present invention. 
         FIG. 1B  is an alternate perspective view of the anchor bolt locator of the present invention. 
         FIG. 1C  is an exploded, perspective view of the anchor bolt locator of the present invention, showing the placement of fasteners to secure the anchor bolt locator. 
         FIG. 1D  is a perspective view of the anchor bolt locator of the present invention, attached to and set in a concrete slab form. 
         FIG. 1E  is a side view of the anchor bolt locator of the present invention, attached to and set in a concrete slab form, showing the concrete in the form. 
         FIG. 2A  is a plan view of the blank of the chair of an anchor bolt locator of the present invention. 
         FIG. 2B  is a plan view of a chair of an anchor bolt locator of the present invention, after openings have been cut in the chair, and the depression and the legs bent from the bridge of the chair. 
         FIG. 2C  is a plan view of an anchor bolt locator of the present invention. The structural nut has been attached to the chair. 
         FIG. 2D  is a sectional view of a chair of an anchor bolt locator of the present invention taken along line  2 D- 2 D of  FIG. 2B . 
         FIG. 2E  is a sectional view of a chair of an anchor bolt locator of the present invention taken along line  2 E- 2 E of  FIG. 2B , with a structural nut shown above the chair and ready for placement in the chair. 
         FIG. 2F  is a partial sectional view of an anchor bolt locator of the present invention similar to  FIG. 2E , with the structural nut now set in place on the chair, and the chair having been modified to frictionally engage the nut, securing it in place. 
         FIG. 3A  is a plan view of a blank of a chair of an anchor bolt locator of the present invention. The anchor bolt locator shown in  FIGS. 3A-3F  is similar to the anchor bolt locator shown in  FIGS. 2A-2F , except the anchor bolt locator shown in  FIGS. 3A-3F  receives a smaller structural nut. 
         FIG. 3B  is a plan view of a chair of an anchor bolt locator of the present invention, after openings have been cut in the chair, and the depression and the legs bent from the bridge of the chair. 
         FIG. 3C  is a plan view of the anchor bolt locator of the present invention. The structural nut has been attached to the chair. 
         FIG. 3D  is a sectional view of the chair of the anchor bolt locator of the present invention taken along line  3 D- 3 D of  FIG. 3B . 
         FIG. 3E  is a sectional view of the chair of the anchor bolt locator of the present invention taken along line  3 E- 3 E of  FIG. 3B , with the structural nut shown above the chair and ready for placement in the chair. 
         FIG. 3F  is a partial sectional view of the anchor bolt locator of the present invention similar to  FIG. 3E , with the structural nut now set in place on the chair, and the chair having been modified to frictionally engage the nut, securing it in place. 
         FIG. 4A  is a plan view of a blank of a chair of an anchor bolt locator of the present invention. The anchor bolt locator shown in  FIGS. 4A-4F  is similar to the anchor bolt locator shown in  FIGS. 2A-2F  and  FIGS. 3A-3F , except the anchor bolt locator shown in  FIGS. 4A-4F  receives an even smaller structural nut. 
         FIG. 4B  is a plan view of a chair of an anchor bolt locator of the present invention, after openings have been cut in the chair, and the depression and the legs bent from the bridge of the chair. 
         FIG. 4C  is a plan view of the anchor bolt locator of the present invention. The structural nut has been attached to the chair. 
         FIG. 4D  is a sectional view of the chair of the anchor bolt locator of the present invention taken along line  4 D- 4 D of  FIG. 4B . 
         FIG. 4E  is a sectional view of the chair of the anchor bolt locator of the present invention taken along line  4 E- 4 E of  FIG. 4B , with the structural nut shown above the chair and ready for placement in the chair. 
         FIG. 4F  is a partial sectional view of the anchor bolt locator of the present invention similar to  FIG. 4E , with the structural nut now set in place on the chair, and the chair having been modified to frictionally engage the nut, securing it in place. 
         FIG. 5A  is a plan view of a blank of a chair of an anchor bolt locator of the present invention. The anchor bolt locator shown in  FIGS. 5A-5F  is similar to the anchor bolt locator shown in  FIGS. 2A-2F ,  FIGS. 3A-3F  and  FIGS. 4A-4F , except the anchor bolt locator shown in  FIGS. 5A-5F  receives an even smaller structural nut. 
         FIG. 5B  is a plan view of a chair of an anchor bolt locator of the present invention, after openings have been cut in the chair, and the depression and the legs bent from the bridge of the chair. 
         FIG. 5C  is a plan view of the anchor bolt locator of the present invention. The structural nut has been attached to the chair. 
         FIG. 5D  is a sectional view of the chair of the anchor bolt locator of the present invention taken along line  5 D- 5 D of  FIG. 5B . 
         FIG. 5E  is a sectional view of the chair of the anchor bolt locator of the present invention taken along line  5 E- 5 E of  FIG. 5B , with the structural nut shown above the chair and ready for placement in the chair. 
         FIG. 5F  is a partial sectional view of the anchor bolt locator of the present invention similar to  FIG. 5E , with the structural nut now set in place on the chair, and the chair having been modified to frictionally engage the nut, securing it in place. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1A , shows the preferred, non-welded anchor bolt locator  1  of the present invention made from a galvanized sheet metal chair  2  and a structural nut  3  attached to the chair  2  by way of a friction fit. 
     As shown in  FIG. 1A , preferably the chair  2  of the anchor bolt locator  1  is a u-shaped body having a bridge  4  that connects two legs  5  and  6 . Preferably, the bridge  4  is substantially rectangular with pairs of opposed sides and the legs  5  and  6  of the chair  2  are connected to the bridge  4  at one pair of opposed sides. Preferably, the legs  5  and  6  of the chair  2  depend from the bridge  4  at right angles to the bridge  4 . Preferably, the plurality of legs  5  and  6  extend away from the top surface  7  of the of the bridge  4 . 
     As shown in FIGS.  1 E and  2 D- 2 F, 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  FIGS. 1B ,  2 C and  2 D, edge openings  14  may be formed in the side wall  10  of the depression  8  where the flat faces  13  of the outer surface  11  of the polygonal nut  3  meet at nut side edges  15 . These edge openings  14  are particularly needed when a deep depression  8  must be made for a tall structural nut  3 , and the metal of the side walls  10  must be particularly stretched to make the depression  8 . The edge openings  14  may also be formed in the side wall  10  to extend into the bottom floor  16  of the depression  8  where the nut side edges  15  meet the bottom end  17  of the nut. The side wall  10  of the depression  8  extends away from the top surface  7  of the bridge  4 . 
     As shown in  FIGS. 2B and 2C , the depression  8  in the bridge  4  is formed with a bottom floor  16  that has a top surface  18 . As shown in  FIGS. 1A-1E , the structural nut  3  is received in the depression  8  of the bridge  4 . As best shown in  FIGS. 2C and 2E , the structural nut  3  has a top end  19 , a bottom end  17 , an internal, threaded bore  20  forming an internal, threaded side wall  21 , and an outer side wall  12  defining an outer surface  11  of the nut  3 . The bottom end  17  of the structural nut  3  rests on the top surface  18  of the bottom floor  16  of the depression  8 , and portions of the outer surface  11  of the outer side wall  12  of the structural nut  3  are in contact with and in frictional engagement with portions of the inner surface  9  of the side wall  10  of the depression  8  such that the structural nut  3  is secured to the chair  2 . 
     As shown in  FIGS. 1A and 2E , preferably, the outer side wall  12  of the nut  3  extends at a right angle to the top and bottom ends  19  and  17  of the nut  3 . Preferably, the side wall  10  of the depression  8  in the bridge  4  extends at right angle to the generally planar portion  22  of the bridge  4  surrounding the depression, and the generally planar portion  22  of the bridge  4  surrounding the depression  8  extends at a right angle to the outer side wall  12  of the structural nut  3 . 
     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  FIGS. 2C and 2F . Preferably, a portion  22  of the bridge  4  surrounding the depression  8  in the bridge of the chair  2  is a substantially planar and relatively thin member. As such, the structural nut  3  between the top end  19  and the bottom end  17  will have a thickness that is substantially greater than the relatively thin portion  22  of the bridge  4  surrounding the depression  8 . Similarly, the depression  8  in the bridge  4  to accommodate the structural nut  3  will have a depth from the top surface  7  of the bridge  4  to the bottom floor  16  of the depression  8 , with portions of the side wall  10  of the depression  8  extending from the top surface  7  of the bridge to the bottom floor  16  of the depression  8 , and that depth of the depression  8  will be substantially greater than the relatively thin portion  22  of the bridge  4  surrounding the depression  8 . 
     As shown in  FIGS. 1B and 2B , preferably, the depression  8  in the bridge  4  of the anchor bolt locator  1  is formed with an opening  23  in the bottom floor  16 . Preferably, the opening  23  is located at the center of the depression  8  and will align with the center of the internal bore  20  in the nut  3 . This allows for accurate placement of the anchor or threaded rod  24 . The opening  23  is preferably an irregular opening  23  that creates a plurality of tongues  25  that extend underneath and support the structural nut  3  at is bottom end  17 . Preferably, at least one of the tongues  25  that make up the bottom floor  16  of the depression  8  extends sufficiently inward from the side walls  10  of the depression  8  to extend past the internal side wall  21  of the structural nut  3 , so as to block the passage created by the internal bore  20  so as to interfere and stop the travel of any threaded rod or anchor  24  received and threaded into the internal passage  20  of the nut  3  past the bottom end  17  of the structural nut  3 . 
     As shown in  FIGS. 1A and 1E , each leg  5  and  6  of the chair  2  is formed with a flow passage  40  to ensure that concrete  26  flows around and under the anchor bolt locator  1  and the threaded rod  24  attached to the nut  3 . 
     Mounting holes  27  are provided in the bridge  4 , preferably at all four corners of the bridge  4 . As shown in  FIGS. 1C ,  1 D and  1 E, fasteners  28 , preferably nails when the form board bottom  29  is wood, are inserted through the mounting holes  27  and fastened to the form board decking  29 , securing the anchor bolt locator  1  to the form  30  in the desired location. 
     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  FIGS. 2A ,  3 A,  4 A and  5 A. Then, the depression  8  in the bridge  4  for receiving the nut  3  is formed and the legs  5  and  6  are bent down from the bridge  4  along bend lines  31 . See  FIGS. 2B ,  2 D,  3 B,  3 D,  4 B,  4 D and  5 B,  5 D. At the same time, embossments  32  are formed in the bridge  4  outwardly from the depression  8 . The depression  8  of the chair  2  is then ready to receive the nut  3  which is placed in the depression  8 . See  FIGS. 2E ,  3 E,  4 E and  5 E. The structural nut  3  is placed in the depression  8  so that portions of the outer surface  11  of the outer side wall  12  of the structural nut  3  are in alignment and in close proximity to portions of the inner surface  9  of the side wall  10  of the depression  8 . Once the nut  3  is received the embossments  32  formed outwardly from the depression  8  are clampingly pressed back into the original plane of the bridge  4  of the chair  2 . See  FIGS. 2C ,  2 F,  3 C,  3 F,  4 C,  4 F and  5 C,  5 F. This causes a spreading flow of the material of the embossments  32  toward the depression  8  which causes the side walls  10  of the depression  8  to be pressed against the outer side surface  11  of the nut  3 , causing frictional engagement that holds the structural nut  3  in place. 
     As shown in  FIGS. 1B and 1C , preferably, the attachment between the anchor  24  and the nut  3  is made by means of corresponding threads in the internal cavity  20  of the structural nut  3  and threads  33  on the outer surface  34  of the anchor  24 . As shown in  FIG. 1E , the anchor  24  is formed with an elongated shank  35  that can protrude above the top level  36  of the concrete slab  26 .  FIG. 1E  shows the top level  36  of the form  30  and the side wall  41  of the form  30 . 
       FIGS. 1D and 1E  illustrate use of the invention. The anchor bolt locator  1  shown is used with a wood form  30  upon which concrete  26  will be poured. In  FIG. 1D , rebar members  37 , a specific type of steel concrete reinforcing member, are shown placed in the form  30 . In  FIG. 1D , chalk lines  38  are also shown on the bottom member  29  of the form  30  to aid in locating the anchor bolt locator  1 . The installer need merely look through the opening  20  in the nut  3  and line up the center of the opening  20  with the intersection of the chalk lines  38 . The installer then nails or screws the anchor bolt locator  1  to the bottom  29  of the form  30  by running the fasteners  28  through the mounting holes  27  in the anchor bolt locator  1 . Once the anchor bolt locator  1  is firmly fastened to the bottom  29  of the formwork  30 , the appropriate anchor  24  or threaded rod is inserted and threaded onto the nut  3 , until the tongues  25  of the depression  8  stop its further downward travel. As shown in  FIG. 1E , typically a washer  38  will then be placed over the anchor  24  so that it rests on the top surface  19  of the structural nut  3  and a second structural nut  39  will be threaded onto the anchor  24  so that it engages the top surface of the washer  38 . This type of double-nut-washer anchorage is commonly used in the industry, because the components are readily available and inexpensive, and yet well documented for their performance as anchors. Concrete  26  is then poured into the formwork  30 , so that the anchor bolt locator  1 , the structural nuts  3  and  39 , the washer  38 , and the threaded rod  24  are all surrounded and embedded in the concrete  26  with the top of the threaded rod  24  or anchor protruding from the top surface  36  of the concrete  26 . When the concrete  26  hardens the form  30  can be removed. If there is access to the bottom  29  of the form  30 , it can be removed as well and the ends of the fasteners  28  that were driven into the bottom formwork  29  can be broken off where they protrude from the concrete foundation  26 .