Patent Publication Number: US-7222466-B2

Title: Foldable support structure with hinged sawtooth wall members

Description:
FIELD OF THE INVENTION 
   The present invention relates to portable support structures for use in temporary fixtures such as trade shows and conventions, and particularly to a portable folding truss system having identical hinging side elements. 
   BACKGROUND OF THE INVENTION 
   Commercial displays such as those used in trade show booths require strong structures that can be easily transported and configurable in a wide variety of forms. Such structures need to be lightweight, portable, and able to be quickly set up and broken down. 
   Prior art solutions have utilized truss members with folding elements that utilize rigid wall members coupled with rotatable wall members. The rotatable side members allow the truss to collapse. The trusses include internal diagonal pivoting members that serve to lock the truss into an open position. Although useful in some applications, this approach has deficiencies. 
   Using differently designed rigid and rotatable wall members increases the required inventory of piece parts needed to build the truss, thereby making the truss more complicated and expensive to manufacture. More importantly, the non-symmetry of the assembled structure (due to the non-rigidity of the rotatable wall members) gives such a truss non-uniform load bearing characteristics when deployed horizontally. Therefore, if the user is not careful and/or cognizant of the requirement for a certain orientation, a structure according to the prior art design might be deployed in an unsafe manner with potentially catastrophic results. 
   What is needed is a collapsible/foldable truss member that is strong, easy fabricated and easily assembled into a temporary or permanent structure for a commercial display or other structural application. What is further needed is a truss member that can be configured to provide horizontal support regardless of the truss member&#39;s orientation. The present invention fulfills these and other needs, and addresses other deficiencies of prior art implementations. 
   SUMMARY OF THE INVENTION 
   To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a foldable truss member having a plurality of adjacently connected side members together forming a peripheral boundary of the truss member. Each side member includes an elongated support member with a side surface and a first end and a bridging member fixably connected to the side surface of the support member at an attachment point of the support member. The bridging member has an extension at an edge of the bridge member opposite the attachment point. A plurality of hinge members pivotably joins the extension of each side member to the support member of the adjacent side member. Each hinge member allows relative rotation of adjacent side members. 
   Each bridging member may include a sawtooth-shaped member having a first and second set of oppositely disposed peaks. The first set of peaks is attached to the attachment point of the associated support member. The extensions of each bridging member are formed by the second set of peaks. 
   At least one of the hinge members can be configured to resist relative rotation of the associated extension at the deployed configuration of the truss member. A hinge member may include an increased friction to resist relative rotation of the associated extension at the deployed configuration of the truss member. A hinge member may include a feature to elastically deform the associated extension to resist relative rotation of the associated extension at the deployed configuration of the truss member. 
   Each hinge member may include a mounting surface and a hinge channel breaking (i.e. bridging or spanning over) a portion of the mounting surface. The extensions of the bridging member of the adjacent side member are locatable within the hinge channel. The mounting surfaces fixably attach to the support members. The hinge channel of each of the hinge members may further include a first and second end, and the first and second ends are flared. The first and second ends may each include a center portion contacting the associated extension when the truss member is in the deployed configuration, at least one terminal portion contacting the associated extension when the truss member is in a folded configuration, and at least one intermediate portion contacting the associated extension when the truss member is in an intermediate configuration between the folded configuration and the deployed configuration. The intermediate portion can be made to offer a resistance to rotation of the associated extension, and the terminal portion can allow substantially free rotation of the associated extension. In one configuration, the center portion offers a resistance to rotation of the associated extension, the resistance of the center portion being less than the resistance of the at least one intermediate portion. 
   In another embodiment of the present invention, a foldable truss member includes a plurality of side member means. The side member means are adjacently arranged so that the lower edges of the adjacently arranged side member means form a closed shape. A plurality of pivoting means are connected between adjacently arranged side member means. The pivoting means allow relative rotation between adjacently arranged side member means so that the side member means are foldable into a substantially flat assembly. 
   Each of the side member means may include a sawtooth-shaped member and an elongated support member. The sawtooth-shaped member has a first and second set of oppositely disposed peaks. The first set of peaks is fixably attached to the support member. The second set of peaks form hinge extensions of the side members. The hinge extensions pivotably attach to the associated pivoting means. Each of the pivoting means may include a mounting surface and a hinge channel breaking a portion of the mounting surface. The mounting surface of each of the pivoting means fixably attaches to the support member of each of the side member means. The hinge extension of the adjacent side member means is locatable within the hinge channel. The hinging means may include friction means to resist relative rotation between adjacently connected side member means at a deployed configuration of the truss member. The hinging means may include elastic deformation means to resist relative rotation between adjacently connected side member means by elastically deforming a portion of the side member means at a deployed configuration of the truss member. 
   In another embodiment of the present invention, a foldable display structure, includes first and second truss members as described hereinabove. A plurality of locking members is disposed between the first ends of the first truss member and the first ends of the second truss member, the first ends of the first truss member being adjacent to the first ends of the second truss member. 
   In one configuration, the first ends of the side members of the first and second truss members each include a recess. Each locking member can include a locking post, the locking posts receivable into the recesses of the side members. At least one locking member may include a locking hole, and the first ends of the associated side members of the first and second truss members each further include a locking hole. The locking members are removably connectable with the associated side members so that the locking hole of the locking members are in alignment with the locking hole of the associated side member. An elongated interference member may be included that is passable through any of the locking holes of the locking members and the locking hole of the associated side member to prevent relative motion of the side members with respect to the locking members. 
   In yet another embodiment of the present invention, a method of assembling a display structure involves forming a truss member by adjacently coupling a plurality of side members to form a peripheral boundary for the truss members. Each of the side members include an elongated edge pivotably attached to the adjacent side member. The truss member is put in an intermediate configuration by relatively rotating the adjacent side members about the elongated edges of the truss member until a resistance to relative rotation is encountered. The truss member is put in a deployed configuration by further relatively rotating the adjacent side members about the elongated edges until a decreased resistance is encountered. 
   The method may further involve slidably connecting an unconnected edge of a second truss member to an unconnected edge of the first truss member to connect the first and second truss members. A locking member can be slidably connected between the first and second truss members. A fastening member can be attached to the first and second truss members to positively connect the truss members together. 
   The above summary of the present invention is not intended to describe each embodiment or every implementation of the present invention. Advantages and attainments, together with a more complete understanding of the invention, will become apparent and appreciated by referring to the following detailed description and claims taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is perspective view of a foldable truss according to one embodiment of the present invention; 
       FIG. 2  is a side view of a side member according to an embodiment of the present invention; 
       FIG. 3A  is a perspective view of a hinge member according to one embodiment of the present invention; 
       FIG. 3B  is a perspective view of the hinge member interacting with a bridge member extension according to the present invention; 
       FIG. 3C  is a perspective view of an alternate hinge member illustrating locking features according to the present invention; 
       FIG. 4  is an end view of the foldable truss member showing a partially folded configuration; and 
       FIG. 5  is a partial side view of a display structure according to one embodiment of the present invention. 
   

   While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail herein. It is to be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. 
   DETAILED DESCRIPTION OF THE VARIOUS EMBODIMENTS 
   In the following description of the illustrated embodiments, references are made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration, various embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized, and structural and functional changes may be made without departing from the scope of the present invention. 
   Referring now to  FIG. 1 , a truss member, generally indicated by reference numeral  100 , includes a plurality of side members  102 . The side members  102  are adjacently connected to form a peripheral boundary of the truss member  100  such that lower (or upper) edges  101  of the side members  102  form a closed shape (e.g. a rectangle). The side members  102  include a support member  104  and a bridging member  106 . The bridging members  106  in the illustrated embodiment are formed of a continuous length of tubular material formed into a generally planar sawtooth shape. The bridging members  106  include one or more extensions  107  located at an edge opposite where the bridging members  106  join the support members  104 . In the configuration illustrated, the extensions  107  are located at distal angular corners of the sawtooth shape. The truss member  100  is formed by joining multiple side members  102  using a plurality of hinge members  108 . 
   The edges  101  of the side members  102  may include receiving members  114 . The receiving members  114  can be used to join multiple truss members  100  together to form a structure. The receiving members  114  in  FIG. 1  are shown as recesses in the support members  104 , although alternate configurations are possible. 
   The hinge members  108  shown in  FIG. 1  are fixed to the support members  104  and pivotably join with the bridging member  106  of an adjacent side member  102 . The hinge members  108  allow relative rotation of adjacent side members  102  while preventing the adjacent side members  102  from separating. In an especially useful configuration, the truss member  100  contains four, pivotable, side members  102 , thereby allowing the truss member  100  to be folded substantially flat for storage and shipment. 
   The hinge members  108  can be configured to hold the truss member  100  in a deployed configuration. In a deployed configuration, the side members  102  are rotated to an orientation so that the truss member  100  takes on the shape desired for the intended installation. Typically, this shape is a rectangle or square (as exemplified in  FIG. 1 ) although it may be desired to make the deployed shape a parallelogram, triangle, or other polygon. The hinge member  108  can include locking or frictional features that hold the side members  102  into position once the side members  102  are oriented in the deployed configuration. Details of the locking and/or frictional features of the hinge members  108  will be described at a later point hereinbelow. 
   Turning now to  FIG. 2 , a side view of an embodiment of a side member  102  is shown. The truss member  100  is formed by adjacently connecting a plurality of side members  102  to form the outer walls of the truss member. Note that the side members  102  can be made substantially identical. Not only does this reduce the number of fabricated piece parts required to fabricated the truss member  100 , it is appreciated that a truss member  100  utilizing substantially identical side members will have symmetric transverse load characteristic (i.e. loads that are perpendicular to the long axis of the truss member). This makes such a truss member  100  ideal for horizontal installations, as there is no need for a preferred orientation of the side members  102 . 
   The side member  102  is formed by fixably attaching a bridging member  106  to a support member  104 . The support member  104  is preferably formed from a tubular material, although it need not be hollow. Any cross-sectional shape of the support member  104  is appropriate, although a rectangular, square, or round cross sectional shape is typically the most useful. The illustrated support member  104  is formed from a square tube material. 
   The bridging member  106  is fixed to one side of the support member  104  at attachment points  204 . The bridging member  106  can be a tubular or bar member bent to a sawtooth shape and attached (e.g. welded or clamped) to the support member  104 . It is appreciated that the bridging member  106  can alternatively be formed from various elements, including a pattern cut from a sheet or any elongated member (e.g. bar) formed into the desired shape. Further, although the bridging members  106  and other truss member components are typically made from metals (e.g. steel, aluminum, copper, brass, zinc, etc), the components can also be made alternate materials such as woods, plastics, carbon fiber and composites. 
   The bridging member  106  includes extensions  107  that interface with hinge members  108  of an adjacent side member  102 . The hinge members  108  are attached to the support member  104  at a location on the support member  104  generally in alignment with the bridging member extensions  107 . The hinge members  108  are typically removably (as opposed to permanently) attached, thereby making assembly easier and allowing for disassembly/reassembly of the truss member  100  for repairs. 
     FIG. 3A  shows an embodiment of an attachable hinge member  108 . The hinge member  108  includes a mounting surface  302  with mounting holes  305 . The mounting holes  305  align with holes on the support member  102  (not shown). The mounting holes  305  are adapted to receive fasteners, such as bolts, screws, rivets, locking pins, etc. The hinge member  108  includes a hinge channel  306  for receiving the extension  107  of a bridging member  106  therethrough. The hinge channel  306  breaks through a portion of the mounting surface  302  and includes flared ends  308  that allow a generally curved extension  107  to freely rotate about 180 degrees within the hinge channel  306 . 
   The hinge member  108  may include features that allow substantial locking of a truss member  100  into a deployed configuration. These features are detailed in  FIGS. 3B and 3C . In  FIG. 3B , a portion of a bridging member  106  is shown in solid line with the extension  107  located within the hinge channel  306  oriented in a typical deployed configuration of the truss member  100 . The orientations of the bridging member  106  corresponding to the folded configurations of the truss member  100  are shown using broken lines. Between the orientations illustrated are intermediate configurations, where the bridging member  106  is located when truss member  100  is being folded or deployed. In one embodiment, the hinge member  106  includes features that hold the extension  107  in a deployed configuration by using either friction and/or elastic deformation of the extension  107 . 
   An example is shown in  FIG. 3C , where the flared end  308  of the hinge channel  306  includes three portions of differing geometry. These portions include one or more terminal portions  310 , a center portion  312  and one or more intermediate portions  314 . These portions  310 ,  312 ,  314  correspond to the orientation of the extension  107  within the hinge member  106  when the truss member  100  is in the folded, deployed, and intermediate configurations, respectively. The terminal portions  310  are designed to offer little or no interference with the extension  107 , thereby allowing easy rotation of side members  102  in the folded configuration. The intermediate portions  314  offer resistance at least where the intermediate portions  314  are adjacent the center portion  312 . The center portion  312  typically offers some resistance to rotation of the extension  107 , although preferably less resistance than the intermediate portions  314 . Having less resistance at the center portion  312  gives the user feedback that the truss member  100  has attained the deployed configuration, because the extensions  107  will “snap” into center portion  312 . 
   The portions  310 ,  312 ,  314  can offer changing resistance to rotation of the extension by various means. In the example of  FIG. 3C , the portions  310 ,  312 , and  314  are formed by fillets that form the hinge channel  308 . It is appreciated that forming a fillet radius different than the inner bend radius of the extension  107  will cause the fillets to ride (interfere) at contact points against portions of the extension  107 . Also, the portions  310 ,  312 ,  314  are arrayed generally radially about a rounded portion  318  of the hinge channel  306 . The rounded portion  318  has a substantially constant semicircular profile throughout the hinge channel  306  in order to effectively restrain the side members  102  during deployment of the truss member  100 . The portions  310 ,  312 ,  314  may have varying shapes and be located varying radial distances from the rounded portion  318  in order to increase or decrease interference with the extension  107 . For example, the intermediate portions  314  are located radially closer to the rounded portion  318  than the other portions  310 ,  312  and are somewhat flattened, thereby giving the flared end  308  a peaked appearance. In this way, the intermediate portion  314  causes an increase in friction and/or elastic deformation of the extension  107 , thereby resisting rotation of the extension  107 . 
   Truss members  100  may be constructed that have a large number of extensions  107  along the side members  102 . In this case, it may be desirable to include a mixture of hinge members  108  alternately configured according the configurations shown in both  FIG. 3A  and  FIG. 3C . This allows the folding action of the truss assembly  100  to be “tuned”, so that holding forces are not excessive while still allowing the hinge members  108  to hold the truss member  100  in the deployed configuration. 
   A truss member  100  can be assembled by locating the extensions  107  of a first side member  102  within the channels  306  of associated hinge members  108 . The hinge members  108  are then attached to the support member  104  of a second side member  102 , trapping the extensions  107  of the first side member  102  between the hinge members  108  and the support member  104 . This process is repeated for all side members  102  so the side members  102  form a closed periphery. 
   After assembly, the truss member  100  can be expanded for use or folded into a substantially flat folded configuration for storage or transport.  FIG. 4  illustrates an end view of a partially folded truss member  100 . The truss member  100  is folded by moving the side members  102  in the direction indicated by the curved arrows in  FIG. 4 . While being folded, the adjacent side members  102  rotate relative to each other at the edges of the side members  102  joined by the hinge members  108 . Expanding the truss member  100  to the deployed configuration involves moving the side members  102  in a direction opposite that indicated by the curved arrows. 
     FIG. 5  is a partial view of a display structure  400  created by connecting two truss members  100  to using locking members  500 . The first and second truss members  100  are expanded to the deployed configuration and placed with edges  101  facing each other. The locking members  500  are slidably attached to the receiving ends  114  on the edges  101  of the first truss member  100 . The second truss member  100  is similarly attached to the locking members  500  and thereby rigidly coupled to the first truss member  100 . 
   A fastening member (e.g interference members)  502  can be used to create a positive locking engagement between the locking members  500  and the truss members  100 . Support member holes  503  (best seen in  FIG. 2 ) and locking member holes  504  are included. During assembly, the holes  503 ,  504  and aligned so that fastening members  502  can be placed through the holes  503 ,  504 . In this example, exemplary fastening members  502  include a quick release pin  510 , a welded nut/lockscrew assembly  512  and a nut/bolt assembly  514 . Other fastening members  502  such as clips, rivets, wire ties, snaps, etc., can also be used to fasten trusses and locking members  100 ,  500 . 
   The truss member  100  and display structure  400  according to the present invention can be beneficially be adapted for all manner of structural uses, particularly those of a temporary or seasonal nature. In particular, one such configuration desirable for uses such as displays or point of sale fixtures is described herein in detail. A truss member  100  having approximately 12″×12″ cross sectional dimensions is preferable in these applications. The individual truss member lengths can vary from about 6″ to about 80″. The support members  102  are formed from ¾″ to 1″ square steel tubing welded to 3/16″ wire lacing forming the bridging members  106 . The hinge members  108  are investment cast from steel and finished with a smooth finish along the hinge channel surfaces  306 . Fabricating the truss assembly  100  from steel offers advantages of low cost, high strength, and magnetic properties for easy attachment of magnetic graphics. The steel is typically powder coated for appearance and corrosion resistance. The support members can be of different sizes and of different materials than stated above, such as round tubes and plastics, aluminum or other materials with sufficient strength. In general, the strength of coupled truss members  100  in this specific application should be able to be safely used over a 40 foot span with no load. Loads up to a few hundred pounds can be supported either applied centrally or distributed. Such load bearing capability would enable the truss to safely support item such as computer or TV monitors, lights and signage, typically used in an exhibit/display. The weight of the truss member  100  so configured will range from ½ pound to 10 lbs for truss lengths between 6″ and 80″ 
   It will, of course, be understood that various modifications and additions can be made to the preferred embodiments discussed hereinabove without departing from the scope of the present invention. Accordingly, the scope of the present invention should not be limited by the particular embodiments described above, but should be defined only by the claims set forth below and equivalents thereof.