Abstract:
A modular truss system includes six-way box connectors to which truss beams can be bolted and pinned together in a wide variety of configurations and to any or all of the six identical faces. Each box connector face and each truss beam endplate is fitted with matching center holes for bolts and spring pin arrangements on the peripheral corners. These make aligning and attaching the truss beams and box connectors to one another a quick and simple job that does not require any tools. The truss beam endplates have one or more spring pins and a center hole that matches the ones in each of the six faces of the box connectors.

Description:
RELATED APPLICATIONS 
       [0001]    This non-provisional application claims priority from United States Provisional Patent Application, titled Modular Truss System, Ser. No. 61/398,857, filed Jul. 1, 2010. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to truss systems typically used in homes, offices, retail space, stages and trade shows. In particular, the present invention relates to truss systems that are built up from six-way box connectors. 
         [0004]    2. Description of Related Art 
         [0005]    Trusses are widely used to support overhead lighting units powered by electrical power cords dressed along the truss raceways. Truss systems for stages and tradeshow floors are available in I-beam, triangle, and square truss sections made from aluminum or steel. Steel trusses are strong enough to permit 40-foot spans, and aluminum trusses have the advantage that they can be made from extruded pieces. Extrusions allow the possibility of including power tracks inside for track lighting heads. 
         [0006]    Trussing typically comes in ten-foot sections, and can be interconnected with 2, 3, 4, 5, and 6-way corners. Conventional interconnections at the ends include the tube-in-socket kind, and those that butt and bolt together at the truss end plates. 
         [0007]    Many trusses erected to support lighting, frames, screens, and other devices are temporary and used over and over again at many different concert and tradeshow locations. It is therefore important that they assembly quickly, easily, and securely. They also need to be light and portable, and rugged enough to keep looking good and resist breaking and damage. Truss systems that can snap together and require no tools for assembly and disassembly are especially desirable. 
       SUMMARY OF THE INVENTION 
       [0008]    Briefly, a modular truss system embodiment of the present invention includes six-way box connectors to which truss beams can be bolted and pinned in a wide variety of configurations to any of the six identical faces. Each box connector face and each truss beam end is fitted with matching center holes for bolts and spring pin arrangements on the peripheral corners. These make aligning and attaching the truss beams and box connectors to one another a quick and simple job and does not require any tools. The ends of the trusses have end plates with one or more spring pins and a center hole that matches the ones in each of the six faces of the box connectors. 
         [0009]    The above and still further objects, features, and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, especially when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a perspective view diagram of three truss beams connected to orthogonal faces of a six-way box connector in a modular truss system embodiment of the present invention; 
           [0011]      FIG. 2  is a perspective view diagram of a six-way box connector useful in the modular truss system of  FIG. 1 ; 
           [0012]      FIG. 3  is a perspective view diagram of a truss beam useful in the modular truss system of  FIG. 1 ; 
           [0013]      FIG. 4  is a perspective view diagram showing how the endplates of two truss beams can be joined in a modular truss system like that of  FIG. 1 ; 
           [0014]      FIG. 5  is a perspective view diagram showing how a six-way box connector useful in the modular truss system of  FIG. 1  can be made from two identical sheetmetal stampings; and 
           [0015]      FIG. 6  is a perspective view diagram showing how a six-way box connector useful in the modular truss system of  FIG. 1  can be made from six individual sheetmetal stampings. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]      FIG. 1  represents a modular truss system embodiment of the present invention, and is referred to herein by the general reference numeral  100 . Assembling modular truss systems  100  begin with six-way box connectors like box connector  102 . In  FIG. 1 , such forms a 90-degree square corner when three truss beams  104 - 106  are attached. Each of the six faces of box connector  102  are identical and provided with five holes. The center hole, e.g.,  108 - 110 , is provided with a weld-nut or cage nut behind, e.g.,  112 - 114 . A knurled bolt (not seen here) is used to secure each of the three truss beams  104 - 106  to box connector  102  without needing a wrench or any other tool. 
         [0017]    The four holes, e.g.,  116 - 119 , at the corners accommodate a spring pin (not seen here) that protrudes from a matching position in the ends of the three truss beams  104 - 106  attached. The central location of the center holes allows the beam trusses to be rotated on the knurled bolts until the corresponding spring pins find a matching corner hole and drops in and locks. 
         [0018]      FIG. 2  provides greater detail of a six-way box connector  200 , in an embodiment of the present invention. The basic shape is a hollow cube  202  made of metal or plastic. The materials are chosen according to the kinds of loads and stresses that will be applied. Twelve access cutouts are provided, e.g.,  204 - 209 , for passing through electrical wiring or the like amongst the attached truss beams. Each of the six faces has a center hole, e.g.,  210 - 212 , for a knurled bolt  214  with a knob  216 , and four equally sized corner holes, e.g.,  218 - 229 , to receive one to four spring pins (shown in  FIG. 3 ). A machine nut, e.g.,  230 - 232 , is disposed behind each of the center holes on the six faces. These can be weld-on nuts, caged nuts, blind nuts, rivet nuts, threaded inserts, or other captive nut. 
         [0019]    The distance between the center hole and each of the four corner holes on each face is the same. During assembly this allows an installer to rotate a truss beam that is loosely held on to a box connector with knurled bolt  214  so a spring pin on the truss beam end plate can find and lock into any of the four corner holes. The knurled bolt  214  is then fully tightened by the installer to secure the connection. 
         [0020]      FIG. 3  represents a truss beam  300  with end plates  302  and  304  that match and can mate with any of the six faces of a box connector like those of  FIGS. 1-2 . A spring pin  306  is disposed in end plate  302 , as is a spring pin  308  in end plate  304 . The spring plate is attached to the end plate by rivet  309  or other means. Each end plate has a center hole, e.g.,  310 , and four corner holes, e.g.,  312 - 315 . These match corresponding holes in the box connectors of  FIGS. 1-2 . 
         [0021]    Four rails, e.g.,  316 - 318 , span between end plates  302  and  304 . When the lengths of truss beams  300  exceed two feet, it is usual to include webbing or one or more gusset spiders  320 , about every two feet maximum. Truss beams  300  are typically provided in standard lengths of two, four, six, eight, ten, and twelve feet. 
         [0022]      FIG. 4  provides further details for the modular truss system illustrated thus far in  FIGS. 1-3 . Two truss beams can be joined at their respective ends  402  and  404  to one another in about the same manner as joining a truss beam to a six-way connector box. Truss beam end  402  has four rails  406 - 409  that terminate in an end plate  410 . A knurled bolt  412  is passed through a center hole  414  in end plate  410  and a matching center hole  416  in end plate  412 . A knurled nut  418  fastens onto the knurled bolt  412  to secure the two truss beam ends  402  and  404  together after a spring pin locks in to an adjoining truss beam end. 
         [0023]    Each truss beam end  402  and  404  includes a spring pin  420  and  422 . In  FIG. 4  they are aligned 180-degrees apart from one another, but they also could be aligned 90-degrees and 270-degrees apart because there are four corner holes to accommodate them on each end plate  410  and  412 . All four corner holes  424 - 427  can be seen for end plate  412  in  FIG. 4 . 
         [0024]      FIG. 5  represents a practical way to manufacture a six-way connector box in an embodiment of the present invention referred to herein by the general reference numeral  500 . Connector box  500  comprises two identical sheetmetal stampings  502  and  504  that are folded and then welded together at their endplates  506  and  508  by tabs  510 - 513 . Only two such tabs  514 - 515  on endplate  508  can be seen in  FIG. 5 . The distal ends of each stamping  502  and  504  are respectively provided with matching tabs  516 - 519 , and  520 - 523 , to complete the welding. 
         [0025]    All six faces of the cube thus formed are provided, e.g., with a center hole  520  and four equally spaced and equally set corner holes  522 - 525 . These are equivalent to center hole  108  and corner holes  116 - 119  in  FIG. 1 ; center hole  210 - 212  and corner holes  218 - 229  in  FIG. 2 ; center hole  310  and corner holes  312 - 315  in  FIG. 3 ; and, center hole  416  and corner holes  424 - 427  in  FIG. 4 . A weld-nut is typically provided behind each center hole  520 . 
         [0026]    Each sheetmetal stamping  502  and  504  is provided with nine access cutouts, e.g.,  530 - 539 . Access cutouts  533  and  539  are full ovals while the rest are half ovals. These allow stage wiring, for example, to be passed through between truss beams joined by connector box  500 . 
         [0027]      FIG. 6  represents another practical way to manufacture a six-way connector box in an embodiment of the present invention referred to herein by the general reference numeral  600 . Connector box  600  comprises six identical sheetmetal stampings, e.g., endplates  601 - 606  that are welded together at their four edges by eight interlocking tabs, e.g., tabs  611 - 618  on endplate  601 . 
         [0028]    All six faces of the cube formed are further provided, e.g., with a center hole  620  and four equally spaced and equally set corner holes  622 - 625 . These are equivalent to center hole  108  and corner holes  116 - 119  in  FIG. 1 ; center hole  210 - 212  and corner holes  218 - 229  in  FIG. 2 ; center hole  310  and corner holes  312 - 315  in  FIG. 3 ; and, center hole  416  and corner holes  424 - 427  in  FIG. 4 . A weld-nut, e.g.,  630 - 632 , is typically provided behind each center hole  620 . 
         [0029]    Embodiments of the present invention are not limited to the six-face box connectors described herein. Three, four, and five faces are also possible, as well as faces set at other than 90-degree orthogonal planes. Each face is nevertheless configured to mate with and be fastened to an end plate of a truss beam using a central bolt and spring pins and holes set at regular intervals around the periphery of the faces and the truss beam end plates. 
         [0030]    Although particular embodiments of the present invention have been described and illustrated, such was not intended to limit the invention. Modifications and changes will no doubt become apparent to those skilled in the art, and it was intended that the invention only be limited by the scope of the appended claims.