Abstract:
A composite wood/metal beam includes a metal support element having a vertical web and horizontal flanges which project from the top and bottom of the web. A plurality of studs which fit entirely between the flanges are attached to the support element. A wood member having the same length and width as the beam is attached to the flange at the top and bottom of the beam. Preferably, some of the studs are attached to the support element in a manner which allows them to be slid along the length of the beam.

Description:
BACKGROUND AND SUMMARY OF THE INVENTION  
         [0001]    This invention relates to a load supporting beam, and in particular to such a beam which is composed of both wood and metal components.  
           [0002]    Beams used in residential and light commercial construction are generally made of wood. Lightweight beams are typically dimension lumber. Intermediate beams are wood I-beams and glue-lam beams are used for heavy loads. However, wood is becoming less available and thus more expensive. Wood beams also have a relatively low strength to weight ratio. In addition, glue-lam beams deteriorate with time and sag. Finally, when a wood beam fails due to overload conditions, such as extreme snow loads, it generally completely fails, which causes serious damage to the structure.  
           [0003]    While metal I-beams could be used for residential and light commercial construction, they generally are not. Available metal I-beams are larger and stronger than are required for this type of application. Thus, they are heavier and more expensive than they need to be. Metal beams also typically require stiffening or bracing, which is labor intensive, and thus expensive. In addition, the majority of the structure in this type of construction is wood and it is more difficult to attach wood components to metal components than it is to attach them to other wood components. Finally, finish work, such as installing Sheetrock, cabinetry and trim is typically done by carpenters who are more familiar with and comfortable with wood components than they are with metal components.  
           [0004]    The subject invention provides a composite wood and metal beam which is lighter and stronger than wood alone, does not sag with time, is less expensive than wood and has plentiful nailable surfaces. The beam has a metal support element having a vertical web with horizontal flanges at its top and bottom extremities. Wood studs, which fit between the flanges and are contained entirely within them, are attached to the support element at desired locations along the beam. A wood member is attached to one or both of the flanges at the top and/or bottom of the beam.  
           [0005]    In one preferred embodiment the support element is a C-shaped channel. In this embodiment, spacer blocks are attached to the channel, on the side opposite the side the studs are attached. The wood member is dimensioned to cover the flanges of the channel and the ends of the spacer blocks.  
           [0006]    In another preferred embodiment, the support element is back-to-back C-shaped channels, the webs of which are joined together. In this embodiment the studs are located on both sides of the beam.  
           [0007]    In another preferred embodiment, the support element is a single I-beam. In this embodiment, studs also are located on both sides of the beam.  
           [0008]    Another aspect of the invention is that some of the studs can be slidably attached to the beam. This allows them to be located where needed once the beam is installed. One way to slidably attach the studs to the beam is to provide a downwardly facing lip at the extremity of the top flange and an upwardly facing lip at the extremity of the bottom flange so that the studs can fit between the web and the lips.  
           [0009]    The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0010]    [0010]FIG. 1 is an exploded view of a beam embodying the subject invention.  
         [0011]    [0011]FIG. 2 is a perspective view of the beam of FIG. 1.  
         [0012]    [0012]FIG. 3 is a perspective view of a modified version of the beam of FIG. 1.  
         [0013]    [0013]FIG. 4 is an exploded view of an alternative embodiment of the beam of the subject invention.  
         [0014]    [0014]FIG. 5 is an exploded view of yet another embodiment of the beam of the subject invention.  
         [0015]    [0015]FIG. 6 is a perspective view of the beam of FIG. 5.  
         [0016]    [0016]FIG. 7 is a perspective view of a modified version of the beam of FIG. 5.  
         [0017]    [0017]FIG. 8 is an exploded view of yet another embodiment of the beam of the subject invention.  
         [0018]    [0018]FIG. 9 is an exploded view of a modified version of the beam of FIG. 8. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]    Referring now to the drawings, a beam  10  combines a metal support element  12  with a wood member  14 . The resulting beam provides the superior strength to weight ratio and low degradation of a metal beam, with the ability to attach surrounding structure and surface materials to the beam with nails, which makes it more desirable for residential or light commercial construction. In addition, the combination of wood and steel provides greater strength than either material would provide alone.  
         [0020]    Referring now to FIGS. 1 and 2, in a first embodiment of the beam the metal support element is a C-shaped channel  16  having a vertical web  18 . Extending outwardly from the top extremity of the web is a top flange  20  and extending outwardly from the bottom extremity of the web is a bottom flange  22 . In the embodiment illustrated, the top flange  20  has a downwardly extending lip  24  at its extremity and the bottom flange has an upwardly extending lip  24  at its extremity. Channels of this type are common in the building arts and are typically rolled steel. The lips  24  are not essential, but they do add some strength and they accommodate attachment of wood studs  26  to the beam.  
         [0021]    The wood studs  26  have a thickness which is slightly less than the width of the flanges  20  and  22  and a height which is slightly less than the height of the web  18 . Thus, they fill the space between the web  16 , the lips  24  and between the top and bottom flanges  20  and  22 . The studs  26  typically are dimension lumber and thus have a width which is greater than their thickness. The studs typically are glued to the flanges  18  by an epoxy adhesive. However, depending on the length of the beam, one or more of the non-end studs may not be glued to the flange. As a result these studs can be slid along the beam to a desired location. This provides flexibility in the use of the studs as a nailing strip. In addition, it allows multiple studs to be placed at points of load concentration on the beam.  
         [0022]    Wood spacer blocks  28  are attached to the web  18  on the other side of the beam  12 . This also preferably is done with an epoxy adhesive. The spacer blocks typically have the same dimensions as the studs  26  and one of their wider sides is placed against the web  18 . Normally a stud and spacer block will be placed at each end of the beam and the number of internal studs and spacer blocks will depend on the length of the beam. The studs and spacer blocks add strength to the beam and serve as nailing strips.  
         [0023]    If desired, the studs and spacer blocks can be covered by thin C-shaped metal caps  30 . The caps  30  are attached to the studs and spacer blocks with an epoxy adhesive. Because the studs and spacer blocks are relatively thin they are prone to splitting when nails are driven into them and the caps  30  greatly reduce the amount of splitting.  
         [0024]    Finally, a wood member  14  is placed on the top and/or bottom of the beam to act as a nailing strip. The wood member has a width equal to the combined width of the flange  20  or  22  and the thickness of the spacer block. The wood member is attached to the respective flange and the ends of the spacer blocks by an epoxy adhesive. The embodiment illustrated in FIGS. 1 and 2 shows a wood member  14  attached to both the top and bottom of the beam and the embodiment shown in FIG. 3 shows it attached to only one side of the beam. In the beam illustrated in FIGS. 1 through 3 the studs  26 , spacer blocks  28  and wood members  14  all are 2×4 dimension lumber. If it is desired to make the beam larger and still utilize the same size channel  16  the spacer blocks  28  can be placed with their narrower sides facing the web  18  and the wood member  32  be 2×6 dimension lumber, as shown in FIG. 4. In this case the caps  30  are not required on the spacer blocks, since the spacer blocks are less likely to split in this orientation.  
         [0025]    The foregoing beam has sufficient strength for light applications such as trusses and typically would used instead of dimension lumber or wood I-beams. For larger applications, which typically require glue-lams, the beam of the subject invention would need to have a thicker web. This can be accomplished using the same components by joining together two of the C-shaped channels  16  with their webs back-to-back as shown in FIGS. 5 and 6. In order to maximize the strength of this beam, the two channels need to be strongly connected. This can be accomplished by spot welding.  
         [0026]    With this embodiment studs  26  are used on both sides of the beam and they are covered with caps  30 . Sliding studs can also be provided on both sides of the beam if desired, but this would not always be the case. If the channels  16  are the same size as the channels in the previous embodiment a 2×4 wood member  14  would be used. While this beam has the same width as the beam shown in FIG. 3, it is considerably stronger. Not only is the web twice as thick, a two-piece web is stronger than a single piece web having the same thickness. In addition, this beam has twice the flange area as the beam shown in FIG. 3. The same beam is shown in FIG. 7 with the wood members  14  only on one side.  
         [0027]    If desired, the support element formed from two back-to-back C-shaped channels can be replaced by a single I-shaped channel  34 , FIG. 8. The channel  34  would have an integral web  36  and flanges  38  with the flanges extending from both sides of the web. Otherwise this beam is similar to the beam shown in FIG. 6 and has studs  26  and caps  30  on both sides. Typically this beam would not have lips on the flanges so it would not have slidable studs. This same beam is shown in FIG. 9 with the wood member  14  only on one side.  
         [0028]    The terms and expressions which have been employed in the foregoing specification are used therein as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow.