Abstract:
The present invention is directed to a framing member for use in a steel framed flooring structure. The framing member has a U-shaped rectangular cross section with two parallel spaced apart flanges and a central web bridging the flanges and connected to one edge of each of the flanges. The central web has an extension on each end thereof, the extension extending beyond the flanges a distance of at least half the width of the flange.

Description:
CROSS REFERENCE TO EARLIER APPLICATION 
     This application is a continuation of application Ser. No. 10/655,619, filed Sep. 5, 2003, now abandoned. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed to a metal framing member, particularly a metal floor joist, having an integral reinforced end. 
     BACKGROUND OF THE INVENTION 
     The framing of buildings for residential and commercial construction has traditionally been accomplished using suitably dimensioned wood members. While the use of wood members makes the construction relatively simple, the use of wood members has its shortcomings. The supply of lumber is getting scarcer and costs have increased during recent years. In addition wood can warp and go out of shape when it becomes wet as well as being susceptible to attack by vermin of various kinds including termites. 
     In recent years buildings framed with sheet metal framing members have been employed. The use of sheet metal framing members provides advantages of dimensional stability, ease of manufacture and conservation of natural resources among others. However the use of sheet metal members, particularly, joists has not gained widespread acceptance for various reasons. One such reason is that the ends of the joists where they are attached to a vertical wall require that they be securely attached to the rim joist and that they be provided with some reinforcement to provide the joist with the capability of supporting the load at the ends. In the past this has commonly been accomplished by using an L shaped bracket of a height about equal to the web of the joist. One leg of the bracket is attached to the web at the end of the joist and the other leg is attached to the web of the rim joist. Another solution employs a section of steel stud or track equal in height to the height of the joist web. The web of the stud or track section is attached to the web of the joist and one flange of the stud is attached to the web of the rim joist. A variation on this is shown in U.S. Pat. No. 5,625,995 issued May 6, 1997 to Byron Martin. This patent describes a special bracket shaped like a stud section for attaching this joist to the header. While these solutions provide the required attachment and reinforcing for the floor joist, they significantly increase the labor time required to install the steel joist system. Consequently steel joist systems have not gained widespread acceptance among the framing trades. 
     A modified ledger or rim joist has recently been described in U.S. Pat. No. 5,956,916 issued Sep. 18, 1999 assigned to Steel Floor Ltd. in an attempt to overcome the above problems. The web of the ledger is provided with struck out tabs which extend perpendicularly inwardly of the web at a regular spacing, typically 16 inches on center. The tabs act as a locating means and attachment means for the floor joist as well as reinforcing the end of the web of the floor joist. While the modified ledger joist makes the attachment of the floor joist easier, it also introduces new problems. The alignment of the ledger must be closely controlled so that the floor joists spanning the space between the ledge will be properly aligned with the struck out tabs. This will require additional labor time by the framing trades. Additionally, as the location of the tabs are fixed at the time of manufacturing of the ledger, the flexibility in the spacing of the floor joists is limited. In some cases such as to avoid a service stack or to provide additional support below partition walls, it may be necessary to adjust the spacing of the floor joist or to install additional joists. In addition if the load characteristics change, the joist spacing required to support the load may change. Another situation where the floor joists will not properly align with the tabs is if the floor joist meets the ledger joist at other than right angles, e.g. 45 degree angles commonly encountered in bay window bump outs. In those cases, another means for providing the attachment and reinforcing of the end of the joist would be required such as the bracket or stud section described above, thus defeating the advantages of the modified rim joist. 
     There thus still remains a need for an easy to install means of attaching a steel framing members such as a steel joist to a supporting framing member such as a rim joist and reinforcing the end of the framing member. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a framing member for use in a steel framed structure. The framing member has a U-shaped rectangular cross section with two parallel spaced apart flanges and a central web bridging the flanges and connected to one edge of each of the flanges. The central web has an extension on each end thereof, the extension extending beyond the flanges a distance of at least half the width of the flange. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred embodiments of the present invention are illustrated in the attached drawings of which: 
         FIG. 1  is a perspective view of a floor joist constructed in accordance with the present invention; 
         FIG. 2  is a perspective view of the end of the floor joist of  FIG. 1 ; and 
         FIG. 3  is a perspective view of a floor constructed using the floor joist of  FIG. 1 ; 
         FIG. 4  is a perspective view of two floor joists of  FIG. 1  meeting over a beam; 
         FIG. 5  is a top plan view of the joists of  FIG. 4 ; and 
         FIG. 6  is a perspective view of a second floor constructed using the floor joist of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A first preferred embodiment of a framing member, particularly a floor joist according to the present invention is illustrated in the attached figures generally indicated by the numeral  10 . 
     The floor joist  10  has a generally C shaped cross section with a web  12  spanning two parallel flanges  14  at opposite edges of the web  12 . The opposite edge of the flanges  14  have an inwardly turned extension to strengthen the flanges when under load. The central web  12  is provided with extensions  16  on each end, the extension  16  having a height slightly less than the height of the web  12 . The extension  16  extends beyond the end of the flange  14  a distance of at least half the width of the flange  14 . Preferably the extension  16  extends beyond the end of the flange  14  a distance of about the width of the flange  14 . When the joist is manufactured, the extensions  16  lie in the plane of the web  12  this allowing the joist to be easily stacked for transportation. In order to make the bending of the extension  16  easier, slots  18  are provided along the desired bend line  20  between the web  12  and the extension  16 . The provision of the slots  18  also forces the extension  16  to be bent along this line. 
     In the construction of a floor, the rim or header joists  30  are attached to the wall, generally by being attached to the top plate  40  of the wall or being directly attached to the vertical surface of a stud  42  of the wall as is common in balloon framing and with walls formed from insulated concrete forms. The extensions  16  of the floor joists  10  are bent, generally perpendicular to the web  12 . The end of the joist  10  is placed in the opening of the rim joist  30 , butting the extension  16  against the web  32  of the rim joist  10 . The extension  16  is then screwed to the web  32  of the rim joist  30  by suitable screws  36  and the flange  14  of the floor joist  10  secured to the flange  34  of the rim joist  30  by screw  36 . 
     As illustrated in  FIG. 4 , when two floor joists  10  meet over a beam  48 , the extensions  16  reinforce the ends of the joists  10 . In those situations, the webs  12  of the joists are attached to one another with suitable fasteners such as screws  36  or bolts. The flange  14  of the floor joists  10  are secured to the beam  48  by suitable fasteners such as screws  36 . 
     As illustrated in  FIG. 5 , the floor joists  10  of the present invention are of particular use where the joists  10  connect to the rim joist or header at other than right angles. In these circumstances, the extension  16  of the floor joist  10  is bent at an angle to match the angle between the floor joist  10  and rim joist  30 . In this way, the extension  16  butts against the web  32  of the rim joist  30  and is easily secured to the web  34  of the rim joist  30 . 
     The framing member of the present invention is manufactured using typical machinery such as roll formers to bend the flanges from a suitable sized blank of metal. The extension and slots may be formed by a cutting machine either before or after the roll forming operation. Once produced the framing members are easily stackable one within another in the typical manner as there are no protrusions beyond the usual C shaped cross section. 
     The dimensions of the framing members of the present invention are those typically used in metal forming. Floor joists produced in accordance with the present invention typically have a depth of 8 to 14 inches, more preferably 8, 10 or 12 inches and the flanges are typically 1½ to 2 inches wide. The joist are typically formed of 14 to 20 gauge steel, most preferably 16 or 18 gauge. 
     As illustrated in  FIG. 3 , the provision of the reinforced end is also of use in the construction of bridging members  50  which are used to interconnect two joists  10  intermediate their ends. The bridging member  50  is provided with the extensions  52  on either end which are bent over to allow the bridging member  50  to be attached to the webs  12  of the joists  10  by screwing through the extensions  52  and into the web  12  of the joist  10 . The length of the bridging member is the same as the spacing between the joists  10 , typically 16 inches, although other lengths are possible depending upon the design of the floor. In order to allow the bridging member  50  to fit between the inwardly turned extensions of the flanges  14 , the height of the bridging member is selected to be equal to or less than the spacing between the inwardly turned extensions. Typically for 8 and 10 inch joists, the height of the bridging member will be 6 inches. This allows the bridging member to fit in the space and be formed using the machinery generally used for 6 inch steel framing members. 
     The extensions may also be used to reinforce the ends of lintels formed by attaching two joists of the required length together back to back, each of the joists having the extensions at either ends. The extensions are bent over to be attached to the studs framing the opening bridged by the lintel. 
     The framing member, particularly the floor joist of the present invention provides for numerous advantages over those of the prior art. The securement of the floor joist to the rim joist does not require the use of additional support members such as brackets or short sections of metal studs, thus resulting in significant labour savings. Similarly, the connection of two floor joists to one another over a beam does not require additional support members, also resulting in labour savings. The floor joists of the present invention are also easily adaptable to situations where the floor joists meet the rim joist or header at other than right angles. 
     Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.