The present application relates generally to truss structures and, more specifically, to a modular truss.
Truss structures may be used to support lights, speakers, screens, scenery, drapes, or other equipment in performance or display spaces. For ease of transporting such truss structures, the structure may be assembled on site from modular segments that are bolted or otherwise coupled together. The assembled truss structure may then be attached to an overhead building structure or to ground-based overhead supports and raised above the performance or display space.
In accordance with a first aspect of the present invention, there is provided a truss that includes two chords and a solid rig bar extending between the two chords at panel points of the truss. The rig bar is fixedly coupled at one end to one of the two chords and at its other end to the other chord. The rig bar includes an aperture that can receive, without the use of tools, a removable coupler that is operable to suspend the truss from above.
In accordance with a second aspect of the present invention, there is provided a truss section that includes a plurality of chords extending longitudinally along the truss section. The truss section also includes a corresponding plurality of cross-bars, where each cross-bar extends between a pair of chords, and the cross-bars are located adjacent to one end of the truss section. The truss section further includes an end plate fixedly coupled to the cross-bars, where the end plate has a plurality of apertures and a plurality of ear portions. Each of the ear portions extends from the end plate to cover a corresponding end of one of the chords. The apertures are configured to align with corresponding apertures in an end plate of an adjacent truss section. The apertures can receive connectors that are passed through the adjacent truss section's apertures to fixedly couple the truss sections together.
In accordance with a third aspect of the present invention, there is provided a truss section that includes a plurality of chords extending longitudinally along the truss section and a solid rig bar. The rig bar extends between two of the chords and is fixedly coupled at one end to one of the two chords and at its other end to the other chord. The rig bar includes an aperture that can receive, without the use of tools, a removable coupler that is operable to suspend the truss from above. The truss section further includes first and second pluralities of cross-bars extending between pairs of chords, the first plurality of cross-bars located adjacent to one end of the truss section and the second plurality of cross-bars located adjacent to the other end of the truss section. The truss section also includes first and second end plates fixedly coupled to the first and second pluralities of cross-bars, respectively. The first and second end plates each have a plurality of apertures and a plurality of ear portions. Each plurality of ear portions extends from its end plate to cover corresponding ends of its plurality of chords. The end plates' pluralities of apertures are configured to align with corresponding apertures in an end plate of an adjacent truss section and to receive connectors passed through the adjacent truss section's apertures to fixedly couple the truss sections together.
Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions and claims.
Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.
For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:
A sling 206 is passed beneath the two top chords of the truss 202 at a panel point and the body of a shackle 208 threaded through the ends of the sling. A threaded pin is passed through one lug of the shackle 208, through the eye of the wire rope 204, and screwed into the other lug of the shackle 208. Typically, at least two wire ropes are used to hang the truss 202, each wire rope with an associated sling, where the wire ropes are positioned above panel points of the truss so as to hang vertically. A panel point is a location on a truss where diagonal members are welded next to each other on the truss chords.
Many safety codes require a second, non-flammable tie between the shackle 208 and the truss 202, to keep the truss 202 from falling if the sling 206 should fail, for example in a fire. For such a safety tie, a second wire rope 210 may also be passed beneath the two top chords of the truss 100 and coupled to the shackle 208 using a second shackle 212. In this way, should the sling 206 fail, the truss 202 will still be supported from the wire rope 204 by the shackle 208, the shackle 212, and the wire rope 210.
The truss section 300 includes chords 302 and cross-bars 304 located near the ends of the chords 302. Each cross-bar 304 extends from one chord 302 to another chord 302. Welded to the cross-bars 304 are connection pieces 306A and 306B. The connection pieces 306A and 306B are mirror image L-shaped brackets. A first leg of connection piece 306A is welded to an end-facing surface of a vertical cross-bar 304. Each end of a second leg of the connection piece 306A is welded to a cross-truss facing surface of a corresponding one of the two horizontal cross-bars 304. The connection piece 306B is similarly welded to the other vertical cross-bar and the two horizontal cross-bars,
The connection pieces 306A and 306B have apertures 308 for receiving bolts to clamp the truss section 300 to a similar truss section abutted end-to-end. The cross-bars 304 are set back from the ends of the chords 302 by approximately the thickness of the first legs of the connection pieces 306A and 306B. As such, the exposed faces of the first legs of the connection pieces 306A and 306B are approximately coplanar with the ends of the chords 302.
Similar to the connection pieces 306A and 306B described with reference to
As may be seen in
While the truss section 500 has a rig bar 520 at each panel point, in other embodiments a truss section may have only one rig bar at a central panel point or any other desired number of rig bars at desired panel points. While the truss section 500 has rig bars 520 extending between both the top pair and bottom pair of chords, in other embodiments, a truss section according to the disclosure may have rig bars extending only between the top pair of chords or only between the bottom pair of chords.
Rig bars according to the disclosure may be stamped or otherwise marked with a load rating for the rig bar and/or truss section. Rig bars according to the disclosure may be fabricated with a suitable thickness, to achieve a desired load rating. While the present disclosure shows solid rig bars, it will be understood that in other embodiments, tubular rig bars may be used, with a rig bar according to the disclosure fabricated from a suitable material or with a suitable wall thickness to achieve a desired load rating.
The embodiment shown in
While
In further embodiments, rig bars may be positioned vertically, between a top chord and a bottom chord, to provide connection points for shackles on cables used to restrain horizontal motion of a truss section or truss according to the disclosure. In other embodiments, rig bars extending between either top chords or bottom chords of a first truss section according to the disclosure may receive shackles coupled to cables used to suspend other trusses or truss sections, speakers, screens, scenery, drapes, or other equipment from the first truss section.
An end plate 906 according to the disclosure includes ear portions 907 and apertures 908. (To make
The ear portions 907 are adapted to prevent or minimize crushing or other damage to the ends of the chords 902 when the truss section 900 is dropped, dragged, collides with a wall, another truss section, or any other item, or is otherwise impacted. Such damage to the end of a chord can render a truss section unsafe for continued use, requiring the truss section to be, removed from service, de-rated, or scrapped. The ear portions 907 thus may operate to extend the useful life of the truss section 900.
The end plates 906 are welded to the cross-bars 904 by beads 932 and beads 934. (Only three of the beads 932 and two if the beads 934 are visible in
The end plate 906 is stronger than the connection pieces 306 and 406 described with reference to
The end plates 906 are the same thickness as the legs of the connection pieces 306 and 406, but the endplate 906 includes more material, resulting in a stronger mechanical coupling between truss sections. Additionally, there is more contact area between the end plates 906 on adjacent truss sections than with connection pieces 306 and 406, which may improve compression loading on the conjoined truss sections. Further, the welding pattern for the end plates 906 may use less welding material, however the placement of the welding beads may create a stronger connection between the end plates 906 and the cross-bars 904 than with connection pieces 306 and 406. Still further, the welding pattern for the end plates 906 makes the end plates quicker to install than the connection pieces 306 and 406, which may decrease manufacturing costs.
Additionally, the single plate 906 may be manufactured in a one-step process, which may decrease manufacturing cost from connection pieces 306 and 406, which are typically manufactured in a three-step process. Further, the single endplate 906 replaces a plurality of conventional connection pieces, which may also decrease manufacturing costs.
An end plate 1006 according to the disclosure includes ear portions 1007 and apertures 1008. The ear portions 1007 extend from corners of the end plate 1006 to cover the ends of each of the chords 1002. The end plates 1006 are welded to the cross-bars 1004 by beads 1032 and beads 1034. An aperture 1036 may be formed in the end plate 1006. The end plate is preferably a ⅜″ aluminum plate.
Different from the end plate 906 described with reference to
The rig bars and end plates according to the disclosure may be used with any size truss or truss section. While the embodiments shown are all trusses and truss sections having square cross sections, it will be understood that the rig bars and end plates according to the disclosure may be used with trusses and truss sections having any shape cross section and any number of chords.
While the embodiments described herein are truss sections, it will be understood that other embodiments may be complete, un-segmented trusses. In some embodiments, rig bars according to the disclosure may be used in a complete truss that does not have connection pieces or end plates. In other embodiments, a truss section having rig bars and/or end plates according to the disclosure may be used as a complete truss in one application and combined with other truss sections in other applications.
Although the present disclosure has been described with exemplary embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.