Abstract:
A wall stud utilized in framing structures, the wall stud including C-shaped frame members supported by core elements. The walls studs can be aligned and secured in a track mounted adjacent the top and bottom ends of the wall studs. The wall studs provide good insulation, support, and easy access for the installation of electrical and plumbing equipment.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of Ser. No. 09/035,226 which was filed on Mar. 5, 1998, which is a continuation-in-part of Ser. No. 08/813,695 which was filed Mar. 7, 1997, now abandoned which was a continuation of Ser. No. 08/544,336 filed Oct. 17, 1995 and issued Mar. 3, 1997 as U.S. Pat. No. 5,609,006. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to wall studs generally replacing wooden studs utilized in framing structures such as houses. 
     Wooden studs are common in the construction industry. For many years, lumber was plentiful and inexpensive. Over the years, however, the supply of lumber has diminished. Consequently, lumber is more expensive and good quality lumber suitable for wall studs is more scarce. 
     Furthermore, traditional wood studs are not always the desired material in all applications. For example, fire resistant housing is essential in many areas. Traditional wood studs are also undesirable in areas infected with termites. In addition, it is difficult to run electrical wires and plumbing equipment through walls having solid wooden studs. Designing around these studs can be time consuming and expensive. 
     Previous attempts to design a substitute for wooden studs have been unsuccessful. As with wooden studs, it is difficult to install electrical and plumbing equipment through solid metal studs. Modifying such wall studs is time consuming and can cause structural defects. Because metal is a good conductor of heat, prior art metal studs are also poor insulators. Finally, prior art metal studs are not easily adapted to accommodate electrical outlets and switches and carpenters cannot use nails and screws for adapting the studs in woodwork and molding applications. 
     Therefore, the primary objective of the present invention is the provision of an improved wall stud. 
     A further objective of the present invention is the provision of an improved wall stud that is a good insulator. 
     Another objective of the present invention is the provision of an improved wall stud that provides for the easy installation of electrical and plumbing equipment. 
     A further objective of the present invention is an improved wall stud that is suitable for use with carpenter&#39;s nails and screws. 
     Another objective of this invention is the provision of a wall stud which can utilize cost efficient sold wood substitutes, such as oriented strand board (OSB). 
     A further objective of the present invention is the provision of an improved wall stud which is efficient in operation, economical in manufacture, and durable in use. 
     SUMMARY OF THE INVENTION 
     The foregoing objectives are achieved in the preferred embodiment of the invention, by an elongated wall stud mounted in a vertical position. The wall stud is comprised of two elongated C-shaped frame members, a top core element positioned within the cavity formed by the frame members toward the top end of the stud, and a bottom core element similarly positioned within the cavity between the frame members toward the bottom end of the stud. The core elements are rigid and accept nails and screws. 
     If the wall studs are utilized in framing an outside wall, the embodiment of the invention may include an insulative material positioned within the cavity between the frame members and between the top and bottom core elements. Metal by itself is a good conductor of heat and is therefore a poor insulator. Incorporating an insulative material such as polyurethane or oriented strand board into the stud provides good insulation for outside walls. In addition, the insulative material reinforces the wall stud to ensure that the stud maintains its structural integrity when placed under large loads in outside wall applications. 
     For inside walls, the invention may include additional core elements spaced apart between the top and the bottom end of the stud. These core elements are slidably mounted between the frame members and can easily be adjusted to a desired height to accommodate electrical outlets and switches. A substantial portion of the cavity remains hollow, allowing pipes and electrical wiring to be easily installed in the wall. 
     The core elements are particularly well suited for accepting carpenters nails and screws. As a result, carpenters can interchange wall studs of the present invention and wooden wall studs. A core element made from polyethylene is strong and does not split when deformed or compressed. To frame the stud, a U-shaped track is provided for aligning the studs and securing them to either the top or bottom structural surface. 
     As an alternative, a user with traditional building needs may wish to utilize a more traditional approach. An alternative embodiment uses only wood and steel, but benefits both economically and structurally by using a reinforced oriented strand board. This embodiment achieves all the insulative and structural benefits of wood, but because the care of oriented strand board may be thinner, it is cost effective. Further, by using OSB, the problems of new growth wood now used in traditional studs are avoided. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of the preferred embodiment of the wall stud showing the wall stud used in framing outside and inside walls. 
     FIG. 2 is a perspective view of the wall stud of FIG.  1 . 
     FIG. 3 is a perspective view of the wall stud of FIG. 1 showing a core element slidably mounted. 
     FIG. 4 is a perspective view of the wall stud showing insulative material stored within the cavity of the wall stud. 
     FIG. 5 is a sectional view taken along line  5 — 5  of FIG.  2 . 
     FIG. 6 is a sectional view taken along line  6 — 6  of FIG.  2 . 
     FIG. 7 is a sectional view taken along line  7 — 7  of FIG.  4 . 
     FIG. 8 is a partial perspective view showing wall studs used to frame an outside wall and an inside wall mounted to a lower track. 
     FIG. 9 is a partial perspective view showing an alternative embodiment of the invention. 
     FIG. 10 is a sectional view taken along line  10 — 10  of FIG.  9 . 
     FIG. 11 is an exploded and partial sectional view of an alternative embodiment of the invention. 
     FIG. 12 is a perspective view of one end of the invention. 
     FIG. 13 is a perspective, sectional view of the invention. 
     FIG. 14 is a sectional view taken along line  14 — 14  of FIG.  13 . 
     FIG. 15 is a partial perspective view showing a wall stud with a circuit box mounted thereto. 
     FIG. 16 is a partial perspective view showing a wall stud with a formed circuit box attached thereto. 
     FIG. 17 is a sectional view of another embodiment of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     FIG. 1 shows a plurality of wall studs  10 A and  10 B used in framing an outside wall  12  and an inside wall  14 , respectively. The wall stud  10 B used in framing the inside wall  14 , has two elongated C-shaped frame members  16 . Each frame member  16  has an inside surface  18 . The inside surfaces are spaced apart and facing to form an internal cavity  20 . 
     A bottom core element  22  is positioned within the cavity  20  at the bottom end  24  of the wall studs  10 A and  10 B. The inner surfaces  18  of the frame members  16  partially enclose the bottom core element  22 . To ensure that the frame members  16  do not separate from the bottom core element  22 , keepers  26  on each frame member  16  extend inward and ride between slits  28  in the bottom core element  22 . The top core element  30  is similarly constructed and positioned between frame members  16  at the top end  32  of the wall studs  10 A and  10 B. 
     A center core element  33  is positioned in the center of the stud  10 B within the cavity  20 . Additional core elements  34  and  35  are positioned within the cavity  20  between the top core element  30  and the center core element  33  and between the center core element  33  and the bottom core element  22 , respectively. Center core element  33  and additional core elements  34  and  35  give the wall stud  10 B additional support and also provide a structure for mounting electrical boxes  36 . 
     The electrical box  36  is used to house such things as electrical switches and electrical outlets. The electrical box  36  attaches to the core elements  33 ,  34 , and  35  in a variety of ways. Preferably, the electrical box  36  is glued to the core elements. Screws  38  and/or nails  40  can also be used. Although the center core element  33  is fixed in position along the wall stud  10 B, additional core elements  34  and  35  are left slidably mounted. Thus, the electrical box  36  can be easily adjusted to different heights along the wall stud  10 B by sliding the additional core elements  34  and  35  either up or down the wall stud (see FIG.  3 ). 
     Although the core elements  22 ,  30 ,  33 ,  34 , and  35  can be made from a variety of materials such as wood, polyethylene is the preferred material. Polyethylene will not crack when screws and nails are inserted into the core element. Further, polyethylene is a fire resistant and strong material. 
     Because the wall studs  10 A and  10 B are designed to facilitate the use of carpenter&#39;s nails and screws, a carpenter can easily interchange studs  10 A and  10 B and wooden studs. This is particularly important in customized window and door applications where wooden studs are often preferred. 
     For outside wall applications, a substantial portion of the cavity  20  in the wall stud  10 A is hollow. As a result, electrical wiring  42  and pipe  44  are easily inserted and installed inside the cavity  20 . 
     The wall stud  10 A used in outside wall applications is similar to the wall stud  10 B used in inside wall applications. The top and bottom core elements  30  and  22  are positioned at the ends of the wall stud  10 A. In framing an outside wall, it is desirable that the wall be a good insulator. Thus, wall studs  10 A also contain an insulative material  46  positioned within the cavity  20  between the top core element  30  and the bottom core element  22 . A variety of insulative materials can be used. The preferred material, however, is polyurethane. Polyethylene has an R-factor of approximately 7, more than three times that of wood. Furthermore, when wood absorbs moisture, its insulating factor is even lower. 
     In addition to providing good insulation, outside walls must also be able to support large loads. Polyurethane is a strong material and inserting polyurethane into the cavity  20  of the wall stud  10 A reinforced the stud and ensures that the stud maintains its structural integrity. 
     Polyurethane and other insulative materials can easily be cut and shaped to provide access for electrical wires  42  and pipe  44 . The electrical box  36  can be mounted to the insulating material  46  using glue, nails, screws, and the like, or any combination. 
     FIG. 5 is a sectional view of the frame members  16 . Each frame member has a back wall  48 , side walls  50  and  52 , and keepers  26 . The inside surfaces  18  of the frame members  16  partially enclose the core elements  22 ,  30 ,  33 ,  34 , and  35  and the insulative material  46  (see FIGS.  6  and  7 ). The preferred material for the frame members  16  is galvanized steel. 
     It is relatively inexpensive to increase the size of the wall studs  10 A and  10 B from, for example, a 2×4 to a 2×8. The same frame members  16  and only slightly larger core elements and insulative material are used. In contrast, increasing the size of a wooden stud results in a significant additional cost. 
     Once center core element  33  is slid into position in the center of the wall stud  10 B, the center core element  33  is secured by punching through side walls  50  and  52  of the frame members  16 . The resulting punch  54  secures the center core element  33  along the wall stud  10 B. Using a punch to secure the center core element  33  is only one means of securing the core element along the stud  10 B. Top and bottom core elements  22  and  30  are similarly secured at the top end  32  and bottom end  24  of the wall stud  10 A and  10 B, respectively. Additional core elements  34  and  35  are left slidably mounted along the wall stud  10 B so they can be easily adjusted in height to accommodate electrical boxes  36 . 
     As shown in FIG. 1, the top and bottom core elements  22  and  30  of the wall studs  10 A and  10 B can be nailed or screwed to wooden plates  56 . This represents a significant advantage over prior art metal studs that cannot easily be attached to wood. Although the embodiment as shown in FIG. 1 works well in a variety of appplications, there are many instances in which wood is not the desired material. An alternative means of mounting the studs  10 A and  10 B is shown in FIG.  8 . The wall studs  10 A and  10 B are positioned in a lower U-shaped track  58 . The lower track  58  is made of galvanized steel or similar material. 
     The lower track  58  has a back wall  60  and side walls  62  and  64  projecting upward. The bottom end  24  of the wall studs  10 A and  10 B abuts the back wall  60 . The side walls  50  and  52  of the frame members  16  fit against the side walls  62  and  64  of the lower track  58 . Nails or screws  66  are inserted through the back wall  60  and into the bottom core element  22  to secure the wall stud  10 A or  10 B in the lower track  58 . Similarly, a screw or nail  66  can be inserted from the bottom core element  22  and into the back wall  60 . The lower track  58  can be secured to the foundation using a variety of attachment mechanisms. 
     Note that wooden studs, in addition to wall studs  10 A and B, can also be easily mounted in the lower track  58 . Consequently, the same lower track  58  can be used with a wall consisting of both wooden studs and wall studs  10 A and  10 B. 
     Replacing the customarily used wooden plate  56  with a metal lower track  58  has many advantages. The metal lower track  58  is fire resistant, resilient, and light weight. In areas where termites are especially troublesome, replacing wood with metal also prolongs the life of the wall. 
     Similarly, an upper track can also be used to align and position the wall studs  10 A and  10 B at their top ends  32 . 
     As previously stated, it is particularly important that wall studs  10 A used in outside wall applications be able to support large loads. As the studs increase in size, additional support is often desired to withstand twisting and bending forces. This is particularly important when the design of the present invention is rotated and used as a joist. FIG. 9 illustrates an alternative embodiment of the invention. Except as described below, the structural member  68  is identical to the wall stud  10 A. Because the structural member  68  may be rotated to a horizontal position in operation, top and bottom core elements  30  and  22  are now referred to as the first and second core elements  70  and  72  (not shown), respectfully. Similarly, the top and bottom ends  32  and  24  of the frame members  16  are referred to as the first and second ends  74  and  76  (not shown). 
     The insulative material  46  is reinforced with a truss  78  that extends along the longitudinal axis of the frame members  16  within the cavity  20  between the frame members. The truss  78  is immersed within the insulative material  46  (see FIG.  10 ). Molding the insulative material  46  around the truss  78  reinforces the insulative material, which in turn reinforces the structural member  68 . This enables the structural member  68  to withstand large twisting and bending forces. The preferred material for the truss  78  is metal. 
     FIGS. 11 shows another embodiment of wall stud  10 C which, like wall studs  10 A and  10 B can be used in framing either an outside wall  12  or an inside wall  14 . The wall stud  10 C has two elongated generally C-shaped frame members  16 , and due to the unique shape of the channels  80 , varying depths of core material  82  can be utilized. The preferred material for the core  82  is OSB, or oriented strand board. For example, FIG. 11 shows a core material  82  which is approximately half the depth of a traditional wall stud. However, given the additional strength added by the channels  16 , the improved wall stud of the present invention has equal or greater strength. Further, oriented strand board is more cost efficient than traditional wooden studs and can be impregnated with fire and insect resistant chemicals or additives. It also is much less likely to warp than current new growth wood studs. 
     The C-shaped channels  80  extend substantially the entire length of the wall stud  10 C. A wooden cap  84  can be placed at either end of the core material  82  and can be mounted by screws, nails, adhesives, and the like to provide a solid base. C-shaped channels  80  are provided with a lip  86  for additional support of the cap  84  when mounted on the core material  82 . As shown in FIG. 11, cap  84  is secured to the core material  82  by a nail  88  or rivet  89 . Likewise lip  86  is attached to cap  84  by a nail or rivet  89 . A filler  90  or wooden level which approximates the shape of the space between the two C-shaped channels can also be added at the ends of the wall stud  10 C to provide a generally traditional wall stud cross section. A similar filler  90  is placed on the opposite side and can be mounted to core material  82  by screw  92 . C-shaped channel  80  can be mounted to core material  82  through the use of nails or rivets  89 , or by use of adhesive or epoxy. 
     As best shown in the FIG. 14, C-shaped channel  80  has an external side  94  which runs generally perpendicular to the core material  82 . This external side  94  is preferably the standard width of a wall stud, but can be varying sizes depending on the needs of the user. Diagonal portions  96  extend from the external side  94  toward the core material  82 . Flange  98  extends from the diagonal portion  96  of the C-shaped channel  80  and is used to hold the core material  82  in place or to attach the channel  80  to the core material  82 . Flange  98  can extend away from the external side  94  of the C-shaped channel  80  as shown in FIG. 13 or can extend inwardly as shown in FIGS. 14 and 17. As mentioned above, rivet  89  extends through flange  90  to attach channel  80  to the core material  82 . In addition, an adhesive or epoxy (not shown) can be used on the surface of flange  98  closest to core material  82  in addition to, or in lieu of, rivet  89 . 
     As with the previous embodiments, the core material  82  may be provided with passages  100  for electrical wiring, plumbing, and the like. 
     In addition, circuit boxes  36  may be mounted on fillers  90  as found at the ends of the stud  10 C and as shown in FIG.  15 . In addition, circuit boxes and other attachment can be molded to specifically fit the angle of the channel  80  as shown in FIG.  16 . 
     The embodiments of the present invention have been set forth in the drawings and specification, and although specific terms are employed, these are used in a generic or descriptive sense only and are not used for purposes of limitation. Changes in the form and proportion of parts as well as in the substitution of equivalents are contemplated as circumstances may suggest or render expedient without departing from the spirit and scope of the invention as further defined in the following claims.