Abstract:
A hoist pick up bar, which has its entire clamp system inside the footprint of the truss. A benefit of placing the hoist inside the truss allows designers to raise the truss structure itself higher since the hoist is no longer above it. In embodiments, the device has clamps that move out of the way so that the device can be lowered on to the truss.

Description:
[0001]    This application claims priority from provisional application No. 61/541,388, filed Sep. 30, 2011, the entire contents of which have herewith been incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    Trusses are often used in stage lighting applications to hold stage lights and other items as supports relative to the stage, e.g., above the stage level as supported from a supporting beam above a stage or other object of lighting. 
         [0003]    Overhead items such as lights, winches and other overhead items, can be mounted on a truss. 
         [0004]    Different ways of truss mounting can be desirable. 
       SUMMARY 
       [0005]    An embodiment describes a truss end support that supports between open ends of trusses. According to an embodiment, this allows mounting items such as a hoist inside the outer extent of the truss. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIGS. 1A-1D  shown the truss support holding a chain hoist, inside a truss, from different angles of the truss; 
           [0007]      FIG. 2  shows details of the adjustable truss end support in its open position; 
           [0008]      FIG. 3  shows the truss end support in its closed position, closed around supports of a truss; 
           [0009]      FIG. 4  shows a side view of the truss; and 
           [0010]      FIGS. 5A-5E  show different size truss bars, and their hole configurations. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    An embodiment describes a hoist pick-up bar intended to mount on a truss and hold a held device inside the truss. The hoist pick up bar is designed specifically for the demands of the concert touring industry. In this embodiment, the bar holds a chain hoist inside a truss and allows the chain to be moved up and down once in operation. This allows for pre-rigging of most hoists inside the truss while preparing in the shop and then hanging the pre-rigged hoist. Using pre-rigged hoists to travel inside the truss allows all work be done prior to site install. This can expedite time on site during load-ins and load-outs as well as tightening the truck pack. 
         [0012]    The Pick-up Bar, when attached, is entirely inside the footprint of the truss. A benefit of placing the hoist inside the truss allows designers to raise the truss structure itself higher than would otherwise be possible with a top mounted hoist. The attached hoist can also be located entirely inside that footprint, according to an embodiment. 
         [0013]    An embodiment is fabricated of aluminum in an embodiment and is available in three standard truss sizes—20.5-inch, 24-inch and 30-inch. 
         [0014]    The device is used for hanging chain motors inside or under stock aluminum box trusses. It can also be flipped upside-down to attach a chain motor to lift the trusses. 
         [0015]    Embodiments are described in the detail in the attached. 
         [0016]      FIGS. 1A-1D  show the device as attached/ installed in a truss.  FIG. 1A  shows a front view of the truss assembly, including the truss,  100 , which is attached to either permanently or temporarily, a truss dolly  110 . The truss dolly  110  includes wheels  115  allowing moving the truss. This can be used to assemble the truss components and prepare for install. 
         [0017]    The truss itself  100  includes spaced support bars that form the truss. The hoist pick up bar  140  is attached between two of these support bars, connected to a hoist drive  130  with a movable chain  150 .  FIGS. 1A ,  1 B and  1 C and  1 D show this from different angles, showing how the hoist pick up bar is attached to the truss in a way that maintains the hoist itself  130  inside the outer perimeter of the truss. 
         [0018]    Note also that while the chain  150  is shown extending outside the outer perimeter of the truss  100 , here into the area of the truss dolly  110 , this chain can be contracted further so that it stays within the truss area itself, or extended so that it extends even further outside the truss. 
         [0019]      FIG. 2  shows a drawing of the truss pickup bar  140  in its open position, where the clamps of the pickup bar are not clamped to sides of a truss. The truss pickup bar includes a housing part  200  formed of two separated aluminum spanners formed of machined aluminum plates. The spanners are shown as  400 ,  402  in  FIG. 4 . These two spanners are separated by a spacing device, e.g., a bolt. The spanners also include connection portions such as  205  for connecting attached parts, and also includes connection holes such as  210  for holding a loadbearing hook or other structural part, shown as  220 . Many of these parts are located between the two different spanner sides  400 ,  402 , thereby placing them in the center of gravity or off the center of the hoist pickup bar. 
         [0020]    Each of the two sides includes a clamp attachment portion shown generally as  220 . The clamp attachment portion includes a truss-engaging portions  225 ,  226  at opposite ends of the portion. A first rounded portion  225  is formed on an outer surface of the two separated spanners. A second rounded portion  230  is attached to and moveable relative to, the spanners. The second rounded portion  230  is formed as part of a clamp portion  235 . The clamp  235  is loosened and tightened via a threaded bolt  236  which is adjusted via a wingnut  237 . 
         [0021]    When the clamp  235  is loosened, it is in the position shown in  FIG. 2  with the two rounded portions  225 ,  230  being separated. This facilitates placing the supporting bar of the truss between the rounded portions. In this open position, the body of clamp  235  is horizontally and innerly offset from the rounded portion  225 . This allows the portions  225 ,  226  to be lowered onto respective bars of an appropriately sized truss, e.g., the bar  300  of the truss as shown in  FIG. 3 . In this open position, the bottom part of the clamp can be moved horizontally, out of the way. 
         [0022]    Once the body is located on the truss, the clamps can be moved to below the two supports of the clamp, and the wingnut  237  can be tightened to drive the clamp portion  235  and  236  towards and against the rounded portions  225 ,  226 . 
         [0023]    In an embodiment, each of the curved portions define less than 120° of an arc of a circle. This allows the curved portions to connect to the truss without extending outside the outer horizontal extent of the truss. For example, this is shown in  FIGS. 1B and 1D , where the outer extent of the truss shown as  155  is substantially even with or slightly extended from the end  156  of the pickup bar. When clamped into place, this leaves approximately 120° or more of the truss on clamped, but prevents the pickup bar from extending outside the horizontal extent of the truss. 
         [0024]    The holes such as  210  can also hold shackle  220  between the two spanners sides, with the shackle having a load holding portion  221  adapted to carry the chain hoist or other device. The shackle can be held in place by the bolt  210  which extends through both sides of the spanner, with the bolt terminated with a Cotter pin  211 . 
         [0025]    In operation, the clamps  235  have their rounded section  230  at one side, and at the other side includes a beveled area  242 . The beveled area when tightened presses against the support along the slot area shown generally as  244 , thereby even further pressing the parts into place. 
         [0026]    The slot area  244  sliding the bolt  236  into that open position shown in  FIG. 2 , and then into the closed position as shown in  FIG. 3  where the two rounded areas oppose one another. This facilitates hanging the device over a truss, since in the open position, the device can be lowered onto the truss, without the bottom portions interfering with the lowering of the truss. This is facilitated by the 
         [0027]    According to embodiments, the pickup bar can be formed in different sizes including 20.5 inches, 24 inch, 30 inch, or any other size to fit a standard size truss, thereby pressing and hinging the rounded area  230  into adjacency with supports of the truss. 
         [0028]    The holes that hold the Shackle are intentionally off-center so that the center post of the Shackle can be held between the two holes and centered in between those two holes. In different embodiments, there can be different numbers of holes, to allow the shackle to be located in the different locations. In one embodiment, the engraving on the device explains the load path, to facilitate the users using this properly.  FIGS. 5A and 5B , for example, show the etching on two different sides of the 30 inch bar. The words “load path” are shown as  502  on one side of the device, showing also the location where the Cotter pin  504  is located through the device. 
         [0029]      FIGS. 5C and 5D  show the hole dimensions for the 24 inch bar, and  FIG. 5E  shows the hole placement and dimensions for the 20½ inch bar. 
         [0030]    Where a specific numerical value is mentioned herein, it should be considered that the value may be increased or decreased by 20%, while still staying within the teachings of the present application, unless some different range is specifically mentioned. Where a specified logical sense is used, the opposite logical sense is also intended to be encompassed. 
         [0031]    The previous description of the disclosed exemplary embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these exemplary embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.