Abstract:
A cargo bar for retaining loads in a cargo container having opposing side walls. The cargo bar includes telescoping sections and end devices at the opposed ends of the cargo bar. The end devices are elastameric and absorb excessive forces that induce pressure grip extension of the telescoping sections.

Description:
RELATED APPLICATION 
     The present invention is a Non-Provisional Application of Provisional Application No. 60/607,721 filed Sep. 7, 2004 entitled “Compressible Foot Member for Friction Type Cargo Stabilization Devices,” claims priority to said provisional application, and incorporates its specification in its entirety by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to the use of extendable cargo bars that are forcibly extended between opposing wall surfaces for pressure induced grip retention of the bars to the walls. 
     BACKGROUND OF THE INVENTION 
     The use of cargo bars for sectioning off cargo loads is well known. Typically, a cargo carrying truck box has opposed side walls and often it happens that a partial load needs to be transported and that cargo load likely needs to be held in place in the truck box. Cargo bars are elongate extendable/contractible members (e.g., telescoping square tubes) having end pads that can be forcibly pressed against the side walls to grip the flat surfaces of the side walls and hold the cargo bars in place. The bar is butted against the partial load and the ends of the cargo bar pressed into the side walls to fix the bar and thereby retain the load. It will be apparent that although such use is a typical use of the “cargo bar” there are many applications and this description is intended to provide an understanding of the inventive concept and is not intended to limit the applicability of the product of this invention. 
     The cargo bar as explained above relies on opposing pressure gripping end portions and typically encompasses thin rubber or elastameric pads at the opposed ends which function as a slip resistant facing and also to avoid damage to the opposing walls. An important characteristic of truck box application for the cargo bars of the prior art is that the walls will resistively flex to enhance or generate ongoing pressure gripping. 
     As explained the applications for the cargo bar varies and one important consideration is the use of the bar in applications where the opposing walls do not resistively flex. In such instances the forced expansion can cause damage e.g., to the non-flexing side walls or to the cargo bar itself. 
     BRIEF DESCRIPTION OF THE INVENTION 
     A previously proposed solution to this problem is to incorporate metal springs into the cargo bar ends i.e., between the rigid end of the bar and the elastameric pad. Such incorporated springs has not been deemed satisfactory. The spring components add considerable expense and complexity. Also, the resistive force of the spring must be reliably sufficient to produce the necessary gripping force and yet have a predictable release to avoid buckling of the bar and/or opposing walls. This criteria has not been satisfactorily achieved by existing metal spring mechanism and has prompted the present invention. 
     The present invention is believed to solve the deficiencies of the metal springs by the provision of molded rubber bar end devices. The molded rubber bar end devices may be referred to as bar end feet and are configured to fit the bar ends and as fitted to the bar ends, may provide varying degrees of resistive deformation. Such devices can be produced of differing durometers for adapting the bars to differing applications. That is, where the structure of the walls and the cargo bar are substantial and the bars are needed to provide equally resistive cargo retention, the devices will accordingly be provided with a durometer that deforms only when subjected to high forces. The durometer will be reduced where the bar and/or walls are more fragile. Further, the design of the devices can be tailored to produce different levels of resistance. 
     The above invention as briefly explained will be more fully understood and appreciated upon reference to the following detailed description and the drawings referred to therein. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A ,  1 B, and  1 C illustrate a use of the cargo bar for securing a load; 
         FIGS. 2A and 2B  are prior art devices that are in a failed condition; 
         FIGS. 3A and 3B  illustrate the securement devices of the present invention; 
         FIGS. 4A and 4B  illustrate a different embodiment of the invention; and 
         FIGS. 5A and 5B  illustrate a further variation of the invention. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       FIGS. 1A ,  1 B and  1 C illustrate the application of a cargo bar  10  being applied between opposing side walls  12 ,  14 . The cargo bar  10  includes telescoping square tubes having a smaller sized tube  16  slideable into a larger sized tube  18 . A locking device  20  is of conventional design and includes a releasable ratchet wheel  22  and hand lever  24 . Ratchet teeth formed on the small tube are engaged by the ratchet wheel and as the lever  24  is manually pivoted e.g., from the position of  FIG. 1A  to the position of  1 B and then to  FIG. 1C , the bar length is extended (compare the bar length of  FIG. 1A  to that of  FIG. 1C ). 
     In operation, the lever  24  is pivoted to the forward most position ( FIG. 1A ) where the teeth of the wheel  22  disengage from the teeth of tube  16 . The tube section  16  is manually pulled to extend the bar length until the ends substantially span the distance between walls  12 ,  14 , and then the handle  24  is pivoted to force pressure engagement of both bar ends  26 ,  28  against walls  12 ,  14 . During this procedure and with lever  24  only partially thrown, the bar ends will fully engage the walls  12 ,  14 . A final forced pivoting of the lever  24  produces pressure retentive locking of the bar to the walls. 
       FIGS. 2A and 2B  represent problems that may occur with the cargo bar as generally described above. In  FIG. 2A  the walls  12 A and  14 A are rigid. Whereas the bar ends have a thin elastameric pad  30 , they provide insufficient give for the overthrow of lever  24 , and with the successful forcing of level  24  to the closed position, such may result in the buckling of the bar as illustrated at reference  32 .  FIG. 2B  illustrates a more flimsy wall structure  12 B,  14 B. The forced closing of lever  24  may result in the wall being forced beyond its elastic resistivity and thus formed into a permanent bow (see wall  12 B), or the wall may fracture as shown at wall  14 B. 
     Reference is now directed to  FIGS. 3 through 6  which illustrate in more detail the improvement of the present invention. In  FIG. 3A  the entire bar end  26  is an elastamer of a determined durometer and includes gripping nodules  34  formed on the outer face of an elastameric block  36  and having an elastameric connecting flange  38 . The flange  38  is configured to fit the end opening of tubes  16 ,  18 . A pin or bolt  40  extends through a hole in the tube end and through an aligned hole  42  in the flange  38  for securing the bar end  26  to the tube end. 
       FIG. 3B  illustrates the reaction of the bar end  26  to forced engagement of cargo bar  10  with walls  12  and  14 . Whereas the entire bar end  26  will collapse or compress to some degree, the smaller sections of the segments will at least initially bear the brunt of the compression. Note that nodules  34  are visibly compressed and hole  42  is visibly elongated, i.e. flange  38  is forced further into the tube end. This activity occurs when a wall structure  12 ,  14  has a greater resistance to the engaging force C then does the elastameric resistance of the bar end  28 . 
     From the above it will be appreciated that the bar end  26  and the design of the bar end (both structural design and durometer of the elastamer) can be varied to produce greater or lesser force absorption as compared to the resistive force of the walls  12 ,  14 . An example of such design modification structurally is illustrated in  FIG. 4 . Note that, as compared to the design of  FIG. 3 , the flange  38  includes a shoulder segment  44 . 
     In  FIG. 4A , prior to forced engagement of the bar end  26 ′ with wall  12 , there is a space  46  between the tube end and the shoulder segment  44 . Following initial engagement and compression of the nodules  34  and elongation of flange hole  42 , the space  46  is closed and the tube end engages the shoulder segment  44  as shown in  FIG. 4B . At this point the resistance to further compression of the bar end  26 ′ is enhanced. 
       FIGS. 5A and 5B  illustrate a modification to the bar end of  FIG. 4  whereby the spacing  46  is eliminated (shoulder  44 ′ is longer and abuts the tube end in the non compressed state). The various segments of the bar ends  26 ,  26 ′ can be reconfigured as desired to have a different pattern of resistance. It is further repeated with the elastamer itself can be modified to have a different durometer and again provide different patterns of resistance. 
     In conclusion, the concept of the invention is the provision of an elastameric bar end that is tailored to produce a desired compressibility that (a) achieves resistive retention of the cargo bar as applied to opposing walls of a structure, while (b) protecting the wall structure and/or bar structure against a destructively high locking extension via forced closing of the bar&#39;s lever. 
     This concept is believed unique to the design of cargo bars and solves a major concern for users without substantial cost increases. Within the confines of this unique concept, those skilled in the art will likely conceive of numerous modifications and variations without departing from the essence of the invention. Accordingly, such variations and modifications are intended to be encompassed within the broadly defined terms of the claims appended hereto.