Patent Publication Number: US-2007107338-A1

Title: Hold-down connector

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to building construction components and, more particularly, to connectors for anchoring wall studs to foundations or underlying support structures.  
      2. Description of the Invention Background  
      Regardless of whether the frame of a building is constructed from wood and/or steel, such frame structures are commonly subjected to a variety of forces. Among the most significant of such forces are gravity, wind, and seismic forces. Gravity is a vertically acting force, while wind and seismic forces are primarily laterally acting.  
      The walls of a structure fabricated from wood components are commonly formed from a collection of wall studs that are connected to top and bottom members or “plates” at desired spacing schemes (i.e., 16 inches from center to center). The studs and plates usually comprise 2×4 and or 2×6 boards. In metal frame arrangements, the studs and plates commonly comprise C-shaped members that are interconnected, for example, by screws or other fastening techniques.  
      To provide the frame with resistance to the types of lateral forces mentioned above, shear wall panels are often attached to portions of the frame formed by the vertically extending studs and top and bottom plates or tracks such that they extend therebetween. Common forms of shear wall panels include one or more types of sheathing such as plywood, fiberboard, particleboard, and/or drywall to the inside or both sides of the wall frame. In multistory applications or applications wherein high shear forces are contemplated, shear wall panels comprising a sheet of steel with gypsum or other material affixed thereto are commonly employed. These shear wall panels transmit the lateral forces acting on the frame of the building to the walls of subsequent floors below it and ultimately to the foundation upon which the walls are supported.  
      In non-shear applications, common fastener such as nails, screws or bolts are employed to affix the wall structure to the underlying support structure. However, in applications wherein high shear and other forces are contemplated, conventional fastener arrangements employed in non-shear applications are often inadequate. Thus, over the years, various types of connection devices have been developed for connecting the wall studs of a shear wall to the underlying structure or foundation. Such connectors are commonly referred to in the industry as “hold-downs”. Examples of such hold-down connectors are disclosed in U.S. Pat. No. 4,665,672 to Commins et al., U.S. Pat. No. 4,744,192 to Commins, U.S. Pat. No. 4,825,621 to Jensen, U.S. Pat. No. 5,092,097 to Young, U.S. Pat. No. 5,249,404 to Leek et al., U.S. Pat. No. 6,112,495 to Gregg et al., U.S. Pat. No. 6,158,188 to Shahnazarian and U.S. Pat. No. 6,513,290 to Leek.  
      Prior hold-down connectors, however, are commonly screwed to metal studs. In applications wherein relatively high shear and deflection forces are anticipated, upwards of 10 and even up to 48 or more fasteners have been be used to fasten a hold-down to a corresponding stud and attain the required attachment strength. Regardless of whether the installer employs power tools to install the fasteners, the process of installing large numbers of fasteners results in an undesirably slow installation process. In addition, the hold-downs must be made with vertically extending portions that are large enough to accommodate the required number of fasteners.  
      Other attempts at fastening hold-down connectors utilizing welding proved to be difficult, time consuming and cumbersome because the welds were made at the outside back edges of the hold-down itself which provided little space for welding and also made it very difficult to inspect the quality of the welds.  
      Thus, as can be appreciated from the forgoing discussion, there is a need for a simple hold-down connector that can be quickly and easily coupled to metal studs without the use of large numbers of fasteners.  
     SUMMARY  
      In accordance with one embodiment of the present invention, there is provided a hold-down connector that comprises a base plate that has at least one base plate fastener opening therethrough. A back plate is attached to the base plate and at least one side gusset plate is attached to the base plate and the back plate such that it extends therebetween. At least one close-ended welding slot is provided through the back plate. The welding slot has a slot width and a slot length that is greater than the slot width and is less than the length of the back plate.  
      In accordance with another embodiment of the subject invention, there is provided a hold-down connector that comprises a base plate that has at least one base plate fastener opening therethrough. A back plate is attached to the base plate and at least one side gusset plate is attached to the base plate and the back plate such that it extends therebetween. A first welding slot is provided through the back plate. The first welding slot has a first slot width and a first slot length that is greater than the first slot width. A second welding slot is provided through the back plate. The second welding slot has a second slot width and a second slot length that is greater than the second slot width.  
      In accordance with yet another embodiment of the subject invention, there is provided a wall system that includes a support structure and a wall frame supported on the support structure. The wall frame comprises at least one vertically extending metal stud that has a stud web and two stud flanges that protrude from the stud web in spaced-apart relation to each other. The wall system further comprises a hold-down connector that includes a base plate that is attached to the support structure. A vertically extending back plate is attached to the base plate. The vertically extending back plate extends between the stud flanges and is welded to the stud web along at least one slot in the back plate.  
      In accordance with another embodiment of the subject invention there is provided a hold-down connector that comprises a base plate that has at least one base plate fastener opening therethrough and a back plate that is attached to the base plate. The back plate extends vertically therefrom from the base plate and has a length and a width. At least one side gusset plate is attached to the base plate and the back plate and extends therebetween. At least two elongated welding slots are provided through the back plate and at least one other elongated welding slot is provided through another portion of the back plate. At least one of the other elongated welding slots is axially aligned with at least one of the elongated welding slots.  
      Accordingly, various embodiments of the invention provide solutions to the shortcomings of other hold-down connectors and methods of attaching the hold-down connectors to studs in various applications. Those of ordinary skill in the art will readily appreciate, however, that these and other details, features and advantages will become further apparent as the following detailed description proceeds.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      In the accompanying Figures, there are shown present embodiments of the invention wherein like reference numerals are employed to designate like parts and wherein:  
       FIG. 1  is a side elevational view of a portion of a wall structure employing a plurality of hold-down connectors forming one embodiment of the present invention to attach the studs of the wall structure to a portion of a support structure;  
       FIG. 2  is a perspective view of a portion of a pair of studs of the wall structure of  FIG. 1  attached to the support structure with one hold-down embodiment of the subject invention;  
       FIG. 3  is a top view of one base plate embodiment of the subject invention;  
       FIG. 4  is a side elevational view of a hold-down embodiment of the subject invention;  
       FIG. 5  is a front elevational view of the hold-down of  FIG. 4  with the base plate shown in cross-section for clarity and the knockout of a conventional stud shown in phantom lines to illustrate the positioning of the weld slots of the hold-down in relation to the knockout;  
       FIG. 6  is a top view of a hold-down embodiment in relation to a single metal stud;  
       FIG. 7  is a front elevational view of an embodiment of a hold-down connector of the subject invention attached to the web of a stud by two sections of weld;  
       FIG. 8  is a top view of the hold-down and stud of  FIG. 7 ;  
       FIG. 9  is a front elevation al view of another hold-down embodiment of the subject invention with the base plate thereof shown in cross-section for clarity;  
       FIG. 10  is a front elevational view of the hold-down of  FIG. 9  welded to the web of a stud that does not have a knockout adjacent to the hold-down;  
       FIG. 11  is a front elevational view of the hold-down of  FIG. 9  welded to the web of a stud that has a knockout therethrough;  
       FIG. 12  is a front elevational view of another hold-down embodiment of the subject invention;  
       FIG. 13  is a front elevational view of the hold-down of  FIG. 12  welded to the web of a stud;  
       FIG. 14  is a front elevational view of another hold-down embodiment of the subject invention; and  
       FIG. 15  is a front elevational view of the hold-down of  FIG. 14  welded to the web of a stud.  
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      Referring now to the drawings for the purposes of illustrating the present embodiments of the invention only and not for the purposes of limiting the same,  FIG. 1  illustrates a shear wall structure  10  wherein at least two hold-down connectors  100  of one embodiment of the subject invention are employed to attach the shear wall structure  10  to a support structure  12 . The support structure  12  may comprise, for example, a concrete foundation or another wall assembly, etc. The wall structure  10  in this arrangement includes a conventional bottom track  14  that has a web  16  and two upstanding flanges  18 . The bottom track  14  is supported on the support structure  12  and may be attached to the support structure  12  utilizing appropriate conventional fasteners.  
      The shear wall structure  10  further includes a top track  20  that also has a web  22  and a pair of flanges  24 . The top track  20  may be attached to joists, girders, beams, tracks, etc. depending upon the structure that it is designed to support. A plurality of conventional metal studs  32  extend between the top and bottom tracks and are attached thereto. In the wall structure depicted in  FIGS. 1 and 2 , the metal studs  32  are arranged in “back-to-back” or “web-to web” pairs  30  that are spaced at desired intervals of, for example, 16,18, 24, etc. inches “on center”. The reader will appreciate, however, that, depending upon the wall structure&#39;s particular design requirements, single metal studs  32  may be arranged at desired spacing intervals in place of the pairs  30  of back-to-back studs  32 .  
      The metal studs  32  may be of conventional design and each have a web  34  and a pair of flanges  36 . See  FIG. 2 . A return  38  is formed on the end of each of the flanges  34  as shown. The pairs  30  of studs  32  may be attached together with their webs  34  in abutting relationship by fastener screws, welds, etc. The pairs  30  of studs  32  may be attached to the top track and the bottom track by fastener screws  44 . See  FIG. 1 .  
       FIGS. 2-8  illustrate one hold-down connector embodiment  100  of the present invention. As can be seen in  FIGS. 2, 4 , and  5 - 8 , hold-down connector  100  includes a base plate  110 , a back plate  120  and a pair of (“first and second”) side gusset plates  130 . One embodiment of the base plate  110  that is particularly well suited for use with a conventional 3.625 inch metal stud is depicted in  FIG. 3  and may be fabricated from ⅜ inch metal plate.  
      In this embodiment, the base plate  110  may be provided with an opening  112  for receiving a conventional fastener therethrough. In one embodiment, the opening comprises an elongated base plate hole or slot. One embodiment of the base plate  110  depicted in  FIG. 3  may be fabricated from ⅜ inch steel plate and have the following dimensions: dimension “A” is approximately 3 inches; dimension “B” is approximately 2 5/16 inches; dimension “C” is approximately 1⅜ inches; dimension “D” is approximately 1⅛ inches. To facilitate easy assembly and welding of the base plate  110  to the back plate  120  and the gusset plates  130 , the rear corners  114 ,  116  of the base plate  110  may be clipped as shown. For example, dimensions “E” may be approximately 3/16 inch and dimension “F: may be approximately 1 15/16 inches. The skilled artisan will appreciate, however, that the composition and the various dimensions and shape of the base plate  110  and fastener opening  112  may be altered depending upon the sizes of the components (studs, track, fasteners, etc.) without departing from the spirit and scope of the present invention.  
      As indicated above, this embodiment of the hold-down connector  100  of the present invention also includes a back plate  120  and a pair of gusset plates  130 . See  FIGS. 4-6 . The back plate  120  and the gusset plates  130  may comprise an integral component and be fabricated from single piece of steel or the gusset plates  130  may extend from the lateral sides  121 , 123  of the back plate  120  and be welded thereto in the configuration depicted in the above-mentioned Figures. In one embodiment, for example, the back plate  120  and the side gusset plates  130  are fabricated from 10 gage 50 ksi steel. However, other types and thicknesses of metal material could conceivably be used.  
       FIG. 4  illustrates the shape of the side gusset plates  130  of one hold-down connector embodiment of the subject invention. In this embodiment, for example, dimension “G” may be approximately 3½ inches; dimension “H” may be approximately 1 foot-6½ inches; and dimension “I” may be approximately ¾ inch.  
       FIG. 5  is a front elevational view of one embodiment of the hold-down connector  100  of the present invention. As can be seen in that Figure, the base plate  110  may be offset a distance “J” from the bottom ends of the back plate  120  and the side gusset plates  130  to facilitate welding (represented by weld  119 ) of the base plate  110  to at least the gusset plates  130  and preferably to the gusset plates  130  and the back plate  120 . The back plate  120  has a width “K” that will enable the back plate  120  to extend between the stud returns  38  as shown in  FIGS. 6 and 7 .  
      Also in this embodiment, the back plate  120  is provided with a pair of elongated (welding) slots  122  that have “closed ends”. As used herein, the term “closed end” means that the slot does not extend longitudinally through either end of the backing plate. In this embodiment, the slots  122  are oriented such that they extend past the lateral sides of a “knockout” opening  40  that is commonly provided through the web  34  of the metal stud  32 . See  FIGS. 5 and 7 . As can be seen in  FIG. 7 , the knockout opening  40  is typically approximately 4 inches long (dimension “L”) and its bottom edge is commonly approximately 10 inches (dimension “M”) from the bottom of the stud  32 . The knockout  40  is shown in phantom lines in  FIG. 5  for illustration only. In this embodiment, the knockout  40  does not form any part of the back plate  120 .  
      Each of the slots  122  has a slot length “N” and a slot width “O”. In one embodiment, the slot length “N” is greater than the slot width “O” and is less than the length “H” of the back plate  120  such that the slot  122  is not open ended. In one embodiment, for example, the slot length “N” is at least fifty percent of the length “H” of the back plate  120 , but is not greater than or equal to the length “H”. That is, in at least one embodiment, the slots  122  do not extend through the upper or lower ends of the back plate  120 , but stop short of those ends of the back plate  120 . See  FIG. 5 . For example, in one embodiment, the slot length “N” is approximately  10  inches, the slot width “O” is approximately ¼ inch and the length “H” of the back plate  120  is approximately 1 foot-6½ inches. The top edges of the slots  122  may be approximately 1 inch from the upper end of the hold-down  100  (dimension “P” in  FIG. 5 ). Each slot  122  has an inside edge  127  and an outside edge  129 . The inside edges  127  of each slot  122  may be approximately ¾ inch from the centerline (“CL”) of the hold-down  100  (dimensions “Q” in  FIG. 5 ). The back plate  120  may then be welded (welds  160 , 160 ′) to the web  34  of the stud  32  through the slots  122  as shown in  FIGS. 7 and 8  such that one weld  160  is applied to one of the outside edge  129  of one of the slots  122  and another weld  160 ′ is applied to the outside side  129  of the other slot  122 .  
      The hold-down connector  100  may be attached to the support structure  12  by a suitable fastener arrangement  170 . In the embodiment depicted in  FIGS. 2-8 , a conventional anchor bolt  172 , nut  174 , and washer  176  are employed. Other suitable fasteners may be employed without departing from the spirit and scope of the subject invention.  
       FIGS. 9 and 10  depict another hold-down connector embodiment  200  of the present invention. Hold-down connector  200  may be substantially similar to the hold-down connector  100  as described above, except that hold-down connector  200  has a single slot  222 . As can be seen in those Figures, the hold-down connector  200  has a base plate  210  that may be of the same construction and configuration as base plate  110  described above. Base plate  210  has a fastener opening  212  therethrough that may have the same characteristics as fastener opening  112  described above. Hold-down connector  200  also has a back plate  220  and a pair of gusset plates  230 . The gusset plates  230  may be integrally formed with the back plate  220  or they may comprise separate pieces that are welded to the back plate  220 . Gusset plates  230  may be of similar construction and size as the gusset plates  130  described above.  
      In this embodiment, a single slot  222  may be provided through the back plate  220 . In the embodiment depicted in  FIGS. 9 and 10 , slot  220  is axially aligned with the center axis CL of the back plate  220 . However, the slot  220  may be situated on either side of the axis CL if desired. The slot  222  has a slot length N′ and a slot width O′. In one embodiment, for a back plate  220  that has a length H′ of approximately 1 foot-6½ inches and a width K′ of approximately 2¾ inches, the slot length N′ may be approximately 1 foot-2 inches and the slot width O′ may be approximately 34 inches. Slot  222  has two side edges  223 ,  225 . Other slot sizes and shapes may be employed.  
      In the embodiment depicted in  FIG. 10 , the stud  32  does not have a knockout  40  located in the vicinity of the slot  222  when the hold-down connector  200  is positioned as shown. Thus, continuous beads of weld  260 ,  260 ′ may be applied to the edges  223 ,  225 , respectively as shown in  FIG. 10  to connect the hold-down connector  200  to the web  34  of the stud  32 . For those applications wherein the stud  32  does have a knockout  40  therethrough, depending upon the design loads of the hold-down connection  200 , the installer may be able to simply apply the welds  260 ,  260 ′ to the portions of the edges  223 ,  225  of the slot  222  oriented above and below the knock out  40  as shown in  FIG. 11 .  
      Somewhat similar to the embodiment depicted in  FIG. 11 , a hold-down connector  300  may be provided with at least two axially aligned slots  322  that each have edges  323 ,  325 . See  FIG. 12 . The hold-down connector  300  may otherwise be substantially identical to the hold-down connector  200  described above. In particular, the hold-down connector  300  has a base plate  310 , a back plate  320  and two gusset plates  330 . The base plate  310  has a fastener opening  312  therethrough. As can be seen in  FIG. 13 , the hold-down connector  300  is attached to the web  34  of the stud  32  by two beads or sections of welds  360 ,  360 ′ applied to the slot edges  323 ,  325 , respectively. In alternative embodiments, the slot  322  that is situated above the knockout  40  in the stud  32  may not be axially aligned along the central axis CL with the welding slot  322  that is situated below the knock out  40 . In addition, one or more of the slots may have opposing side edges or portions that are not parallel to each other.  
      Another embodiment of the present invention is depicted in  FIGS. 14 and 15 . As can be seen in those Figures, the hold-down connector  400  of this embodiment has three “upper” slots  422 ,  432 ,  442  located in a portion of the back plate  420  that would be above the hole  40  in a corresponding stud  32  when installed and three “lower” slots  426 ,  436 ,  446  in the portion of the back plate  420  located below the hole  40  in the corresponding stud  32 . In the embodiment depicted, the slots  422 ,  432 ,  442  are the same size and shape and are substantially laterally aligned with each other. However, in other embodiments, the upper slots  422 ,  432 ,  442  may have different sizes and shapes and/or may not be laterally aligned with each other. In addition, in the embodiment depicted in  FIGS. 14 and 15 , the upper slots  426 ,  436 ,  446  are substantially the same size and shape and are laterally aligned with each other. In other embodiments, however, the lower slots  426 ,  436 ,  446  may have different sizes and shapes and/or may not be laterally aligned with each other. Also, as shown in  FIGS. 14 and 15 , upper slot  422  is axially aligned with the lower slot  426 . The second upper slot  432  is axially aligned with the second lower slot  436  and the third upper slot  442  is axially aligned with the third lower slot  446 . In other embodiments, one or more of the upper slots may not be aligned with corresponding lower slots. It will also be appreciated that other numbers of upper and lower slots may be employed. For example, in another embodiment, only two upper slots and two lower slots are provided. In other embodiments two upper slots and three lower slots are provided and in yet another alternative three upper lost and two upper slots are provided. Thus, the number, size, shape and arrangement of upper and lower slots may vary depending upon the expected loading conditions.  
      The hold-down connector  400  may otherwise be substantially identical to the hold-down connector  200  described above. In particular, the hold-down connector  400  has a base plate  410 , a back plate  420  and two gusset plates  430 . The base plate  410  has a fastener opening  412  therethrough. As can be seen in  FIG. 15 , the hold-down connector  400  is attached to the web  34  of the stud  32  by beads or sections of welds  460  applied through each of the slots  422 ,  432 ,  442 ,  426 ,  436 ,  446 .  
      The various embodiments of the subject invention represent vast improvements over prior hold-down arrangements. Various embodiments may be attached to the web of a stud by welding, thus eliminating the need to install several fastener screws.  
      The invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. The embodiments are therefore to be regarded as illustrative rather than restrictive. Variations and changes may be made by others without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such equivalents, variations and changes which fall within the spirit and scope of the present invention as defined in the claims be embraced thereby.