Patent Publication Number: US-6658806-B1

Title: Support for a strap holdown

Description:
BACKGROUND 
     This invention relates to an elongate connector for securing a vertically disposed structural member to a concrete foundation. The connector is partially embedded in a concrete foundation and fasteners attach the connector to the structural member to be anchored. According to the present invention, the embedded portion of the connector is formed with a keyhole opening or slot that, in the preferred embodiment, can receive the intermediate head and hold the shank of a standard double-headed nail. The slot is located in the embedded portion of the connector such that the tip of the nail can be partially driven into a wooden form board or other member. A form board, as used here, is a member used to define the boundaries of a poured concrete foundation or other cementitious member. By connecting the double-headed nail to the connector and to the form board the nail serves as a brace for the connector. This helps to keep the connector plumb, during the pouring of the concrete. 
     As is evidenced by such previous patents as U.S. Pat. No. 5,150,553, granted to Alfred D. Commins on Sep. 29, 1992, and U.S. Pat. No. 5,813,182, also granted to Alfred D. Commins on Sep. 29, 1998, connectors that are partially embedded in a concrete foundation and are attached to a vertically disposed structural member by means of fasteners are well known in the prior art. U.S. Pat. Nos. 5,150,553 and 5,813,182 are incorporated herein by reference. These connectors, commonly called strap anchors, have been widely accepted by builders due to the ease with which they can be installed, and their relatively low cost in comparison to other types of anchors. 
     Strap anchors, as described above, are generally elongate members. They protrude above the upper level of the foundation considerably. Strap anchors are generally designed to be attached with light fasteners such as nails. A large number of nails are generally needed to make a secure attachment between the connector and the structural member. Thus the upper portion of the connector must be rather long to accommodate the larger number of fasteners. 
     The fact that a considerable portion of a strap anchor protrudes above the level of the foundation raises problems during the pouring of the cement around the strap anchor. Generally, strap anchors are attached to the outer form boards near the tops of the form boards by means of typical fasteners such as nails. The inventor has found that during a typical foundation pour, the flowing concrete has a tendency to move the strap anchor out of the alignment it originally had when it was attached to the form board. This is thought to occur because the attachment of the strap anchor to the form board is insufficient. 
     To improve the connection between the form board and the strap anchor so that the anchor is less likely to be moved out of its original alignment, the inventor has devised an additional attachment between the form board and the strap anchor. 
     SUMMARY OF THE PRESENT INVENTION 
     It is an object of the present invention to provide an improved connection and a method of making that connection between a connector and the form from which it is suspended, so that the connector remains in alignment during the pouring of a cementitious member. 
     The improved connection is achieved by making an additional attachment between the connector and the form. The additional attachment is made possible because the embedded portion of the connector is formed with a opening that can receive and hold the shank of a nail that is partially driven into a form board. 
     In one form of the invention the additional attachment is made with a double-headed nail. Preferably, the embedded portion of the connector holds the upper portion of the shank of the double-headed nail between the end most head and the intermediate flanges or head of the nail. 
     In another form of the invention, the nail is held by a narrow or constricted portion of a specially shaped opening, having both an enlarged portion and a constricted portion. This shaped opening can be keyhole-shaped. The constricted portion of the opening is shaped so that the side of the opening lies closely adjacent to the shank of the fastener near at least two points on the shank of the fastener. The constricted portion of the opening can be shaped with two substantially opposed side edges spaced just enough from each other to receive the shank of the nail. The enlarged portion of the opening can be circular in shape to closely receive the head of a fastener. 
     To make the connection the nail is moved into position by inserting the nail through the wide portion of the opening such that the shank is received thereby. The nail is driven partially into the form board. Then the shank of the fastener is slid out of the wide portion and into the narrow portion of the keyhole opening. The form board is preferably the same form board to which the strap anchor is already attached. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1A is a orthogonal view of a strap anchor suspended from a foundation form board. A double-headed nail is shown that is ready to be inserted partially through an opening in the foot section of the strap anchor. 
     FIG. 1B is a orthogonal view of a strap anchor suspended from a foundation form board. A double-headed nail has been inserted partially through the keyhole opening in the foot section of the connector and hammered partially into the form board. The shank of the nail is shown being received by the enlarged portion of the opening in the foot section. 
     FIG. 1C is similar to FIG. 1B, except that the shank of the nail is shown being received by the constricted portion of the opening in the foot section. 
     FIG. 2 is a front view of a connector embedded in a foundation. The foot portion of the connector is shown in solid lines although it would be hidden by the foundation. Phantom lines show a portion of a form board disposed on the outer surface of the foundation. 
     FIG. 3A is a side view of a connector suspended from a foundation form board. A standard nail is shown ready to be partially inserted into a keyhole opening in the foot section of the connector. The keyhole opening is shown in phantom lines. 
     FIG. 3B is a side view of a connector suspended from a foundation form board. A double-headed nail has been partially inserted through the keyhole opening in the foot section of the connector and hammered partially into the form board. The shank of the nail is shown being received by the enlarged portion of the opening in the foot section with the uppermost head of the fastener disposed on the side of the foot section away from the form board. The intermediate head of the fastener is disposed between the foot section of the connector and the form board. 
     FIG. 3C is similar to FIG. 3B, except that the shank of the nail is shown being received by the constricted portion of the opening in the foot section and the concrete has been poured into the form. The foot section is shown in solid line although it would be hidden by the cement of the foundation. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION 
     As is best shown in FIGS. 1C and 2, one aspect of the present invention is a connection between a connector  1  and a form board  2 . The form board  2  is used to form a cementitious member  3 . The form board  2  has an inner surface  4 . As is shown in FIG. 3C, the cementitious member  3  has an outer surface  5  that is, at the least, in a partially abutting relationship with the inner surface  4  of the form board  2 . The cementitious member  3  also has a top surface  6 . 
     Referring to FIG. 3A, the connection between the form board  2  and the connector  1  is provided in part by a fastener  7 . As is best shown in FIG. 3A, additional fasteners  8  can be used to attach the connector  1  to the form board  2 . As is shown in FIG. 1C a special holder  9  can be also be used instead of additional fasteners  8  to attach the connector  1  to the form board  2 . 
     According to the present inventive connection, the fastener  7  is held by the form board  2  and protrudes from the inner surface  4  of the form board  2 . Referring to FIG. 3A, the fastener  7  has an elongated relatively narrow shank  10 . The shank  10  has a tip  11  that is formed to be embedded in the form board  2 . The fastener  7  also has a head  12  at the opposite end of the shank  10  from the tip  11 . The head  12  is held way from the inner surface  4  of the form board  2 . The head  12  is wider than the relatively narrow shank  10 . 
     As is shown in FIG. 3C, in the present inventive connection, the connector  1  has an attachment section  13  that has at least some portion protruding out of the cementitious member  3 . The attachment section  13  is connected to the foot section  14 . The foot section  14  is at least partially embedded in the cementitious member  3 . As is shown in FIG. 1A, the foot section  14  is formed with at least one opening  15 . The opening  15  has a constricted portion  16  communicating with an enlarged portion  17 . The enlarged portion  17  is larger than the constricted portion  16 . The constricted portion  16  is too narrow to allow the head  12  of the fastener  7  to be received therethrough. In the inventive connection, the foot section  14  is embedded in the cementitious member  3 , the tip  11  of the shank  10  is embedded in the form board  2  and the shank  10  of the fastener  7  is received by the constricted portion  16  of the opening  15  in the foot section  14  of the fastener. All of the figures, except FIG. 3A, show the preferred fastener  7 ′ which is a double-headed fastener  7 ′. 
     As is shown in FIGS. 1A , 2  and  3 A, in the preferred embodiment of the connection the foot section  14  has a first side face  18  and a second side face  19 . The first side face  18  is disposed towards the inner surface  4  of the form board  2 . 
     Also in the preferred form of the connection, the fastener  7 ′ has a second head  120 ′ that lies between the tip  11 ′ of the shank  10 ′ and the head  12 ′ at the end of the shank  10 ′. This is shown in FIG.  3 B. The second head  120 ′ of the fastener  7 ′ is also wider than the relatively narrow shank  10 ′ of the fastener  7 ′. 
     Such a fastener  7 ′ with two heads  12 ′ and  120 ′ is typically called a double-headed fastener  7 ′. Such fasteners  7 ′ are commonly used in building a form for a cementitious member  3 . The intermediate head  120 ′ of the double-headed fastener  7 ′ can prevent the nail  7 ′ from being driven completely into a wooden member. This allows the nail  7 ′ to be more easily removed from the member, if it is desirable to disassemble the connection made with the fastener  7 ′. For example, after a concrete foundation  3  has been poured and set, the form is disassembled by removing the form boards  2  so that only the concrete foundation  3  remains. If any nailed connections are made with double-headed fasteners  7 ′ and the head  12 ′ at the end of the shank  10 ′ is accessible, the nail  7 ′ can be removed rather easily with the pry bar end of a typical framing hammer. 
     In the preferred form of the connection, as. shown in FIG. 3B, the second head  120 ′ is positioned between the first side face  18  of the foot section  14  and the inner surface  4  of the form board  2 , while the head  12 ′ at the end of the shank  10 ′ is disposed above the second side face  19  of the foot section  14  with the foot section  14  between the head  12 ′ at the of the shank  10 ′ and the form board  2 . 
     This arrangement of the end most and intermediate heads  12 ′ and  120 ′ of the fastener  7 ′ and the foot section  14  of the connector  1  prevents the connector  1  from being pushed either toward or away from the form board  2 , helping to maintain the alignment of the attachment section  13  of the connector  1 . 
     In the preferred form, the opening  15  in the foot section  14  of the connector  1  is formed with the constricted portion  16  of the opening  15  in the shape of an elongated, narrow slot extending away from the enlarged portion  17  of the opening  15 . The narrow slot is closely adjacent or touches the shank  10 ′ of the fastener  7 ′ at at least two points. This is shown in FIG.  2 . This helps to insure that the foot section  14  will not move substantially toward or away from the form board  2 , because the foot section  14  will encounter one of the heads  12 ′ or  120 ′ of the fastener  7 ′. Although the preferred form of the constricted portion  16  is a narrow slot, other arrangements of the side or boundary of the constricted portion  16  are possible. 
     Also in the preferred form, the enlarged portion  17  of the opening  15  in the foot section  14  is circular in shape and has a similar but slightly larger diameter than the intermediate head  120 ′ of the fastener  7 ′. 
     In the preferred form of the invention, the connector  1  has a foot section  14  with substantially planar portions. The foot section  14  has a top end and a bottom end, and, as stated above, the foot section  14  is formed with at least one opening  15  therethrough. The opening  15  has a constricted portion  16  and an enlarged portion  17  communicating with the constricted portion  16 . The enlarged portion  17  is preferably large enough to receive a shank  10 ′ and the intermediate head  120 ′ of a double-headed fastener  7 ′. A double-headed fastener  7 ′ has an intermediate head  120 ′ disposed between the tip  11 ′ of the fastener  7 ′ and the head  12 ′ at the opposed end of the fastener  7 ′. The constricted portion  16  of the opening  15  is preferably formed so that there is at least one point along its length where it is only large enough to closely receive the shank  10  of the fastener  7 ′ on substantially opposed sides of the fastener  7 ′, so that at that point, the opening  15  is too constricted to allow either of the heads of the fastener  7 ′ to pass through the opening  15 . 
     The side of the constricted portion  16  can also closely approach the shank  10 ′ of the fastener  7 ′ at two points on the shank  10 ′ to achieve the desired result of requiring the fastener  7 ′ to be substantially displaced so that the heads  12 ′ and  120 ′ of the fastener &#39; 7  can once again pass through the opening  15 . 
     As is shown in FIG. 1A, the preferred connector  1  is also formed with an elongated, substantially planar attachment section  13  integrally connected to the top end of the foot section  14 . The attachment section  13  is disposed at a selected angle  20  to the foot section  14  to direct the foot section  14  away from the inner surface  4  of the form board  2 . This angle is dependent on such factors as the length of the foot section  14 , and the dimensions of the cementitious member  3 . 
     As is shown in FIG. 1A, in the preferred embodiment, the attachment section  13  is formed with a plurality of restricted openings  21 . These openings  21  are large enough to receive the shank  22  of standard nailable fasteners  23  but too small to receive the heads  24  of standard nailable fasteners  23  when said fasteners  23  are driven through said openings  21  and into a structural member adjacent the attachment section  13 . These fasteners  23  are preferably  16   d  nails. 
     As is shown in FIG. 1A, in the preferred embodiment, the connector  1  is formed with a hook section  25  integrally connected to the bottom end of the foot section  14 . The hook section  25  is formed to provide mechanical interlock with the cementitious member  3 . 
     As is shown in FIG. 2, in the preferred embodiment of a connector  1  formed in accordance with the present invention, a portion of the hook section  25  is wider than the foot section  14 . The hook section  25  is formed with a generally orthogonal bend  26  for creating mechanical interlock with the concrete member  3 . Also, in the preferred embodiment, the hook section is formed with a longitudinal embossment  27  that stiffens both the generally orthogonal bend  26  and the hook section  25 . 
     The location of the opening  15  in the foot section  13  that receives the preferred fastener  7 ′ is determined primarily by the length of the fastener  7 ′ and the angle  20  of the main longitudinal bend  28 . 
     The preferred embodiment of the foot section  14  may also be formed with such features as curled side edges  29 , a drawn opening  30  and a second opening  31  to improve the connection of the foot section  14  with the cementitious member  3 . 
     The preferred embodiment of the connector  1  is formed from galvanized sheet metal. This permits the connector to be made on standard, automated machinery which is common in the sheet metal connector industry. Furthermore, the preferred form requires no secondary operations after it is formed, such as welding or painting. This further reduces manufacturing costs. 
     The preferred form of the connector  1  is also formed in accordance with the preferred embodiment of U.S. Pat. No. 5,813,182, granted Sep. 29, 1998, the contents of which are herein incorporated by reference. 
     As an example, the following is a description of a connector  1  formed in accordance with the preferred form of the present invention that would be used to make a stem-wall-to-wooden stud connection in a typical wood-framed building. The connector  1  is formed from 12 gauge G60 galvanized sheet metal, and is approximately 3″ wide. The foot section  14  and the hook section  25 , together, reach an embedment depth of approximately 8″. 
     The longitudinal embossment  27  in the hook section  25  is approximately 1″ wide by 2¾″ long. The displaced portion of the hook section  25  is 1½″ long by 3″ wide. 
     The foot section  14  is formed with curled side edges  29 , a drawn opening  30 , and the opening  15  for receiving the double-headed fastener  7 ′. The drawn opening  30  is located approximately 4½″ from the orthogonal bend  26  in the hook section  25 . The drawn opening  30  is formed as an obround slot that is approximately 1⅞″ long and ⅞″ wide. The curled side edges  29  reduce the width of the foot section  14 , making it approximately 2 {fraction (7/16)}″ wide. The enlarged portion  17  of the opening  15  for receiving the double-headed fastener  7 ′ is located approximately 4⅝″ from the main bend  28  in the connector  1 . The enlarged portion  17  of the opening  15  is circular and has a diameter of 0.4375″. The constricted portion or slot  16  extends approximately {fraction (13/16)}″ from the center of the enlarged portion  17  of the opening  15 . The slot  16  is approximately 0.1875″ wide between its side edges  32 . 
     The attachment section  13  is approximately 21⅝″ long and 3″ wide. The attachment section  13  is formed with twenty-four obround openings  21  for receiving  16   d  sinkers nails  23  to permanently attach the connector  1  to a stud. Two openings  33  are added to the attachment section  13  near the top end of the foot section  14  to temporarily attach the connector  1  to a form board  2 . The connector  1  is formed with embedment indicia to aid the installer in attaching the connector  1  to the form board  2  at the proper height, so that the fasteners  23  enter the stud at the best height. The foot section  14  is displaced from the plane of the attachment section  13  at a selected angle  20  of 206 degrees. 
     Use and the formation of a connection according to the present invention is illustrated in FIG.  1 A. 
     First, a form is created that is to be filled with an uncured cementitious member  3 . The form consists of form boards  2 , and at least some of the form boards  2  having inner surfaces  4  that will define the outer surfaces  5  of the foundation when the cementitious member  3  has cured. Further, at least some of the form boards  2  have a top surface  34  that will be equal to or above the top  5  of the cementitious member  3  when it has cured. 
     Second, a fastener  7  is selected. According to the present invention, the fastener  7  has a narrow shank  10  with a head  12  attached thereto at one end, the head  12  of the fastener  7  being wider than the shank  10 , and the shank  10  having a tip  11  at an opposite end from head  12  of said fastener  7 . 
     Third, a connector  1  is selected. The connector  1  has an attachment section  13  and a foot section  14 . The attachment section  13  has a bottom end. The foot section  14  is formed with at least one opening  15  therethrough. In the preferred embodiment, the opening  15  has a constricted portion  16  communicating with an enlarged portion  17 . The enlarged portion  17  is larger than the constricted portion  16  of the opening. The constricted portion  16  is too narrow to allow the head  12  of the fastener  7  to be received therethrough. Preferably, the constricted portion  16  is also shaped so that two side edges  32  of the constricted opening closely approach the shank  10  of the fastener  7  at two different points. 
     The foot section  14  also has a top end and a bottom end, and the attachment section  13  and the foot section  14  are connected together at a transition area  35 . The transition area  35  comprises the bottom end of the attachment section  13  and the top end of the foot section  14 . 
     The connector  1  is then suspended in the form such that the transition area  35  is substantially adjacent to the inner surface  4  of one of the form boards  2 . Furthermore, the connector  1  is suspended in such a manner that at least a portion of the attachment section  13  of the connector  1  protrudes out of the form. This is preferably accomplished with the special holder  9 . This holder  9  consists of a base  36  and a wedge  37  that fits into the base  36  and pinches the attachment section  13  of the connector against the base  36 . The base  36  is preferably, removably attached to the form board  2  with double-headed fasteners  7 ′. 
     Suspended in this manner, at least a portion of the attachment section  13  of the connector  1  will protrude out of the cementitious member  3  after it has cured, and preferably, substantially all of the attachment section  13  will protrude out of the cementitious member  3  after it has cured. Meanwhile, the bottom end of the foot section  14  of the connector  1  is disposed within the form and is removed from the inner surface  4  of the form board  2  to which the transition section  35  is substantially adjacent. 
     Next, the shank  10  of the fastener  7  is inserted through the enlarged portion  17  of the opening  15  in the foot section  14  of the connector  1 , and the tip  11  of the fastener  7  is driven into the same inner surface  4  of the form board  2 , such that the fastener  7  is supported by the form board  2 , and the head  12  of the fastener  7  is disposed adjacent to the foot section  14  of the connector  1 . 
     Then, the shank  10  of the fastener  7  is slid into the constricted portion  16  of the opening  15 , which is easily accomplished by tapping on the shank  10  of the fastener  7  in the direction of the constricted portion  16  of the opening  15  with a hammer. 
     Finally, the form is filled with the wet cementitious member  3  and the cementitious member  3  is allowed to cure. 
     According to the preferred method of making the connection, the foot section  14  has a first side face  18  and a second side face  19 . The first side face  18  is disposed towards the inner surface  4  of the form board  2 , when the connector  1  is suspended in the form. Furthermore, the preferred fastener  7 ′ to be used in the preferred method has a second head  120 ′ that lies between the tip  11 ′ of the shank  10 ′ and the head  12 ′ at the end of the shank  10 ′. This second head  120 ′ is also wider than the relatively narrow shank  10 ′. 
     In the preferred method of making the connection, the fastener  7 ′ is driven into the form board  2  at an angle so that the heads of the nail lie parallel with the general orientation of the preferred foot section  14  of the connector  1 . However, the inventor has found that the angle of the fastener  7 ′ is not critical to the performance of the connection. 
     In the preferred method of making the connection, after the tip  11 ′ of the fastener  7 ′ is driven into the inner surface  4  of the form board  2 , the second head  120 ′ is disposed between the first side face  18  of the foot section  14  and the inner surface  4  of the form board  2 , and the head  12 ′ at the end of the shank  10 ′ is disposed above the second side face  19  of the foot section  14  with the foot section  14  between the head  12 ′ at the end of the shank  10 ′ and the form board  2 . 
     In the preferred method of making the connection, the constricted portion  16  of the opening  15  is formed as an elongated, narrow slot extending away from the enlarged portion  17  of the opening  15 . The narrow slot  16  can extend away from the attachment section  13  of the connector  1  or towards the attachment section  13  of the connector  1 . If the narrow slot  16  extends away from the attachment section  13 , the fastener  7 ′ slides into the constricted portion  15  by pulling it down or tapping the shank  10 ′ with a hammer from above. This motion is essentially perpendicular to the shank  10 ′ of the fastener  7 ′.