Abstract:
A box tube clamping system featuring a variable geometry clamp for secure joining of telescoping box tubes. A variable geometry clamp aligns between an inner and an outer box tube and includes a center wedge plate flanked by adjoining wedge plates which are advanced towards the center wedge plate to force the center wedge plate in an upward direction to force the outer box tube and the inner box tube into forced and secure intimate frictional engagement. Installation spacers are included for use with the variable geometry clamp to provide user friendly accommodation of an inner box tube past and along the variable geometry clamp mounted in one end of the outer box tube.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is for a clamping system and, more particularly, is for a system including a variable geometry clamp joining telescoping box tubes, such as for gate arms. 
     2. Description of the Prior Art 
     Prior art clamping systems for gate arms were bolted together. The amount of time for assembly in the field was sometimes significant, because it was necessary to drill holes. In later years, the clamping systems came with predrilled holes, but sometimes the predrilled holes did not always align or were not drilled for the proper distances. 
     The present invention overcomes the problems with the prior art assembly of clamping systems for gate arms by providing a box tube clamping system. SUMMARY OF THE INVENTION 
     The general purpose of the present invention is to provide a box tube clamping system including telescoping box tubes and an interceding variable geometry clamp. Such joined box tubes can be used for railroad grade crossing arms, parking lot security arms, or other situations requiring the attachment of box tubes or arms along a longitudinal axis. An outer box tube telescopingly accommodates an inner box tube of slightly lesser dimension. The outer box tube and the inner box tube are dimensioned such that substantially planar portions of a variable geometry clamp can be accommodated between the lower planar panels of each of the box tubes. The lower panel of the larger of the box tubes includes an elongated hole through which vertically oriented posts of the variable geometry clamp protrude. The variable geometry clamp is comprised of a center wedge assembly flanked by a left wedge assembly and a right wedge assembly. Each wedge assembly includes a wedge plate having opposing bevels and a holed post extending downwardly from the bottom surface thereof. An upwardly facing bevel of the left wedge plate and an upwardly facing bevel of the right wedge plate align intimately in edge to edge, bevel to bevel, horizontal fashion to oppositely oriented downwardly facing bevels of the center wedge plate. A bolt extending through the holes in the downwardly extending posts is incorporated to draw the left and right beveled wedge plates of the left and right wedge assemblies together against the center wedge plate of the center wedge assembly to alter the geometry of the clamp by causing forced upward deflection of the center wedge assembly by action of the impinging bevels. Such a change to the vertical extent of the variable geometry clamp forces mutual frictional and secure engagement of the inner box tube and the outer box tube. 
     According to one embodiment of the present invention, there is provided a box tube clamping system for secure joining of telescoping outer nad inner box tubes. 
     An alternate embodiment discloses installation spacers in the variable geometry clamp which aid in insertion of the inner box tube into the outer box tube. 
     One significant aspect and feature of the present invention is a box tube clamping system having a variable geometry clamp disposed between like planar panels of telescoping box tubes. 
     Another significant aspect and feature of the present invention is a variable geometry clamp having a center wedge assembly disposed between adjoining wedge assemblies. 
     Still another significant aspect and feature of the present invention is the use of wedge assemblies having beveled wedge plates and holed posts extending downward therefrom. 
     Yet another significant aspect and feature of the present invention is the intimate horizontal alignment of beveled surfaces of the beveled wedge plates. 
     A further significant aspect and feature of the present invention is the forcing together of adjoining wedge assemblies of the variable geometry clamp to vary the vertical extents of the variable geometry clamp to force mutual frictional engagement of the inner box tube with the outer box tube. 
     Still another significant aspect and feature of the present invention is the use of installation spacers with a variable clamp assembly which maintains a low and orderly variable clamp assembly profile to aid in the installation of the inner box tube within the outer box tube. 
     Having thus described embodiments of the present invention and mentioned several significant aspects and features thereof, it is the principal object of the present invention to provide a box tube clamping system. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other objects of the present invention and many of the attendant advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, in which like reference numerals designate like parts throughout the figures thereof and wherein: 
     FIG. 1 illustrates an exploded isometric view of the box tube clamping system, the present invention; 
     FIG. 2 illustrates an exploded isometric view of the variable geometry clamp; 
     FIG. 3 illustrates the assembled components of FIG. 2; 
     FIG. 4 illustrates an assembled box tube clamping system; 
     FIG. 5 illustrates a cross section view of the box tube clamping system prior to actuation of the variable geometry clamp to urge the inner and outer box tubes into frictional and mutual engagement; 
     FIG. 6 illustrates a cross section view of the box tube clamping system subsequent to actuation of the variable geometry clamp to urge the inner and outer box tubes into frictional and mutual engagement; 
     FIG. 7, a first alternate embodiment, is an exploded isometric view of the variable geometry clamp of FIG. 2, including installation spacers; 
     FIG. 8 illustrates a cross section view of the box tube clamping system showing partial insertion of the inner box tube into the outer box tube and showing the use of installation spacers in the variable geometry clamp; and, 
     FIG. 9 is a cross section view showing the disengagement of the installation spacers from the variable geometry clamp. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 illustrates an exploded isometric view of the box tube clamping system  10  including an outer box tube  12 , an inner box tube  14  which is telescopingly accommodated by the outer box tube  12 , and a variable geometry clamp  16 . The outer box tube  12 , which preferably is open ended, includes upper and lower opposed panels  12   a  and  12   b  and opposed side panels  12   c  and  12   d . An elongated hole  18  is included in the lower panel  12   b . The inner box tube  14  includes upper and lower opposed panels  14   a  and  14   b  and opposed side panels  14   c  and  14   d . The greater and substantially planar portions of variable geometry clamp  16  align to the lower panel  12   b  and within the confines of the outer box tube  12 , while the lower vertically oriented portions of the variable geometry clamp  16  extend through and beyond the elongated hole  18  in the lower panel  12   b  of the outer box tube  12 . The variable geometry clamp  16  is comprised of a center wedge assembly  22 , adjoining left and right wedge assemblies  24  and  26 , and a bolt  28  and lockwasher  30 , as described later in detail with reference to FIG.  2 . 
     FIG. 2 illustrates an exploded isometric view of the variable geometry clamp  16 . The left wedge assembly  24  includes a wedge plate  32  having a transversely aligned upwardly facing bevel  32   a  opposed to a transversely aligned upwardly facing bevel  32   b . The wedge plate  32  also includes a bottom surface  32   c  and a top surface  32   d . A post  34  including a longitudinally oriented body hole  36  is located off center with respect to the wedge plate  32 . One side of the post  34  aligns to the lower edge of the bevel  32   b  and extends downwardly from the lower edge of the bevel  32   b  and from the bottom surface  32   c  of the wedge plate  32   b.    
     The right wedge assembly  26  includes a wedge plate  38  having a transversely aligned upwardly facing bevel  38   a  opposed to a transversely aligned upwardly facing bevel  38   b . The wedge plate  38  also includes a bottom surface  38   c  and a top surface  38   d . A post  40  including a longitudinally oriented threaded hole  42  is located off center with respect to the wedge plate  38 . One side of the post  40  aligns to the lower edge of the bevel  38   b  and extends downwardly from the lower edge of the bevel  38   b  and from the bottom surface  38   c  of the wedge plate  38 . 
     The center wedge assembly  22  includes a wedge plate  44  having a transversely aligned downwardly facing bevel  44   a  opposed to a transversely aligned downwardly facing bevel  44   b . The wedge plate  44  also includes a top surface  44   c  and a bottom surface  44   d . A post  46  including a longitudinally oriented elongated body hole  48  is located at the center of the wedge plate  44  and extends downwardly from the bottom surface  44   d  of the wedge plate  44 . A plurality of gripping ridges  50   a - 50   n  are located along and about the top surface  44   c  of the wedge plate  44  to facilitate and enhance frictional engagement of the center wedge assembly  22  with the lower panel  14   b  of the inner box tube  14 . The post  34  of the left wedge assembly  24  is oriented towards the post  46  of the center wedge assembly  22  and the post  40  of the right wedge assembly  26  is oriented towards the post  46  of the center wedge assembly  22  for best stabilization and alignment of the components of the variable geometry clamp  16 . The bolt  28  extends through body hole  36  of the left wedge assembly  24  and through the elongated body hole  48  of the center wedge assembly  22  to threadingly engage the threaded hole  42  of the right wedge assembly  26 . 
     FIG. 3 illustrates the assembled components of FIG.  2 . Insertion of the bolt  28 , as previously described, serves to group and align the left wedge  24  assembly, the right wedge  26  assembly and the center wedge assembly  22 . When assembled, the left and right wedge assemblies  24  and  26  are urged into close intimate contact with and about the center wedge assembly  22  with the actuation of the bolt  28 . Accordingly, the upwardly facing bevel  32   b  of the left wedge assembly  24  is in intimate contact with the downwardly facing bevel  44   b  of the center wedge assembly  22 , and the upwardly facing bevel  38   b  of the right wedge assembly  26  is in intimate contact with the downwardly facing bevel  44   a  of the center wedge assembly  22 . Rotary actuation of the bolt  28  in the correct direction draws the left wedge assembly  24  and the right wedge assembly  26  towards each other resulting in the forcing of the center wedge assembly  22  vertically as resultant movement during sliding and forced impingement of the intimately engaged bevels  32   b  and  44   b  and the intimately engaged bevels  38   b  and  44   a.    
     FIG. 4 illustrates an assembled box tube clamping system  10 , the present invention. Illustrated in particular are the posts  34 ,  46  and  40  and the bolt  28  extending through the accommodating elongated hole  18 . 
     Mode of Operation 
     FIGS. 5 and 6 further depict the invention and best illustrate the mode of operation of the box tube clamping system  10 . FIG. 5 illustrates a cross section view of the box tube clamping system  10  prior to actuation of the variable geometry clamp  16  to urge the inner and outer box tubes  14  and  12  into frictional and mutual engagement. Prior to any engagement of the inner and outer box tubes  14  and  12 , the variable geometry clamp  16  is first placed into the elongated hole  18  located in the lower panel  12   b  of the outer box tube  12 , preferably with the bolt  28  rotated appropriately to cause distanced displacement of the left wedge assembly  24  with respect to the right wedge assembly  26 . Such distancing of the left wedge assembly  24  and the right wedge assembly  26  requires that the top surface  32   d  of the wedge plate  32  and the top surface  38   d  of the wedge plate  38  are higher than the gripping edges  50   a - 50   n  extending upwardly from the top surface  44   c  of the wedge plate  44 . The inner box tube  14  can then be aligned within the outer box tube  12  at any time after suitable placement of the variable geometry wedge  16  into the elongated hole  18 . The placement of the variable geometry clamp  16  places the bottom surfaces  32   c  and  38   c  of the left wedge plate  32  and right wedge plate  38 , respectively, in intimate contact with the upper surfaces of the lower panel  12   b  at common areas surrounding the elongated hole  18 . The bolt  28 , the lockwasher  30 , and the posts  34 ,  40  and  46  extend downwardly though the elongated hole  18  and at a sufficient distance beyond the panel  12   b  to await rotation of the bolt  28  for actuation of the variable geometry clamp  16 . 
     FIG. 6 illustrates a cross section view of the box tube clamping system  10  subsequent to actuation of the variable geometry clamp  16  to urge the inner and outer box tubes  14  and  12  into frictional and mutual engagement. During such actuation, the bolt  28  is rotated in the appropriate direction to draw the left wedge assembly  24  and the right wedge assembly  26  towards each other. As the bolt  28  is rotated, the engagement of the threads of the bolt  28  in intimate engagement with the threads of the threaded hole  42  of the post  40  draws the post  40  along a portion of the elongated hole  18 , thus causing the bottom surface  38   c  of the attached wedge plate  38  to slide longitudinally along the lower panel  12   b , as well as along and about a portion of the elongated hole  18 , whereby the right wedge assembly  26  is forcibly repositioned towards the left wedge assembly  24 . An opposing and simultaneous motion occurs with respect to the left wedge assembly  24 . As the bolt  28  is rotated, the engagement of the bolt  28  and lock washer  30  in intimate engagement about the body hole  36  of the post  34  draws the post  34  along a portion of the elongated hole  18 , thus causing the bottom surface  32   c  of the attached wedge plate  32  to slide longitudinally along the lower panel  12   b , as well as along and about a portion of the elongated hole  18 , whereby the left wedge assembly  24  is forcibly repositioned towards the right wedge assembly  26 . As previously described, the upwardly facing bevels  32   b  and  38   b  of the wedge plates  32  and  38  are in intimate contact with the downwardly facing bevels  44   b  and  44   a  of the wedge plate  44 . As the left wedge assembly  24  and the right wedge assembly  26  advance horizontally towards each other, the center wedge assembly  22  is urged and forcibly advanced upwardly by interaction of the advancing and upwardly facing bevels  32   b  and  38   b  with the downwardly facing bevels  44   b  and  44   a . The elongated hole  48  in the post  46  allows for movement of the post  46  of the center wedge assembly  22  about the bolt  28 . The bolt  28  is rotated until the center wedge assembly  22  ultimately causes intimate forced contact of the gripping edges  50   a - 50   n  with the lower panel  14   b  and resultant intimate forced planar contact of the upper panel  14   a  of the inner box tube  14  with the upper panel  12   a  of the outer box tube  12 . Although the use of one variable geometry clamp  16  is described, a plurality of variable geometry clamps  16  could be utilized should additional clamping be desired for the joining of box tubes being of greater length or weight. The joining of box tubes is demonstrated in the invention; however, other tubes or structures could be joined incorporating the teachings of the invention such as, but not limited to, joining dimension lumber to an outer box tube, joining fiber glass railroad crossing arms to an outer box tube, joining an I-beam to an outer box tube, or joining a round inner tube to a rectangular or round shaped tube. Modification of the shape of the wedge plates, such as to provide curved or arced wedge plates or other geometric configurations, shall not be deemed as limiting to the scope of the invention. 
     First Alternative Embodiment 
     FIG. 7, a first alternative embodiment, illustrates an exploded isometric view of the variable geometry clamp  16  shown with similarly constructed installation spacers  52  and  54 . Each of the installation spacers  52  and  54  is fashioned preferably of a plastic, such as a polycarbonate available under the registered trademark LEXAN, or of other suitable plastic or other material, and can be utilized to facilitate and promote substantially unrestricted entry of the inner box tube  14  within the outer box tube  12 , as shown in FIG. 8, without significant interference from the variable geometry clamp  16 . The use of the installation spacers  52  and  54  ensures that a low and orderly profile of the variable geometry clamp  16  is maintained during insertion of the inner box tube  14  into the outer box tube  12 . Each of the installation spacers  52  and  54  is U-shaped and each includes a slot  55  formed by an arcuate surface  56  having vertically aligned wall extensions  58  and  60  extending upwardly therefrom. Installation spacer  52  aligns as a spacer between the post  34  of the left wedge assembly  24  and the post  46  of the center wedge assembly  22  and over and about a portion of the bolt  28  which is accommodated by the slot  55 . In a similar fashion, the installation spacer  54  aligns as a spacer between the post  46  of the center wedge assembly  22  and the post  40  of the right wedge assembly  26  and over and about a portion of the bolt  28  which is accommodated by the slot  55 . 
     FIG. 8 illustrates a cross section view of the box tube clamping system  10  showing partial insertion of the inner box tube  14  within the outer box tube  12  prior to actuation of the variable geometry clamp  16  to urge the inner and outer box tubes  14  and  12  into frictional mutual engagement. Dashed line pairs show the insertional paths  14   e  and  14   f  of the inner box tube  14 . Prior to any engagement of the inner and outer box tubes  14  and  12 , the variable geometry clamp  16  utilizing the installation spacers  52  and  54 , which maintain a low and orderly variable geometry clamp  16  profile, is first placed into the elongated hole  18  located in the lower panel  12   b  of the outer box tube  12 . The installation spacers  52  and  54  are placed as described previously in FIG. 7 between the posts  34 ,  46  and  40  and over portions of the bolt  28  with the bolt  28  being rotatingly positioned to cause the alternatingly spaced posts  34 ,  46  and  40  and the alternatingly spaced and appropriately dimensioned installation spacers  52  and  54  to draw together until the bolt  28  is prevented from further rotation by the compressed geometry of the posts  34 ,  46  and  40  and the interposed installation spacers  52  and  54 . The longitudinal dimensioning or thickness of the installation spacers  52  and  54  is such that upon full tightening of the bolt  28 , the upward travel of the center wedge assembly  22  is limited as the travel of the left wedge assembly  24  and the right wedge assembly  26  is restricted. The inner box tube  14  can be aligned fully within the outer box tube  12  at any time after suitable placement of the variable geometry wedge  16  utilizing installation spacers  52  and  54  into the elongated hole  18 . 
     With respect to the removal of the installation spacers  52  and  54 , as depicted in FIG. 9, it is to be noted that the vertical dimensions of the installation spacers  52  and  54  are such that spaces, such as the immediately viewable and near space  62 , are located between the upper portions of the wall extensions  58  and  60  and the areas of the lower panel  12   b  surrounding the elongated hole  18 . If required, a prying member such as a screwdriver can be inserted into such spaces to pryingly urge the installation spacer  52  from between the post  34  and the post  46  and the installation spacer  54  from between the post  46  and the post  40  in the event that a slightly oversized inner box tube  14  causes resistance to suitable retractive rotation of the bolt  28 . 
     FIG. 9 illustrates a cross section view of the box tube clamping system  10  where the inner box tube  14  has been fully advanced within the outer box tube  14  and advanced along and past the noninterferring variable geometry clamp  16 . Subsequently, the bolt  28  is then rotatingly actuated (as shown) to relieve the compression along the alternatingly spaced posts  34 ,  46  and  40  and the alternatingly spaced installation spacers  52  and  54  prior to actuation of the variable geometry clamp  16  for engagement with the inner box tube  12 . Compressional relief allows the installation spacers  52  and  54  to disengage from frictional engagement between the respective posts  34 ,  46  and  40  and to be released from the structure of the variable geometry clamp  16 . The bolt  28  is then actuated to force the center wedge assembly  22  upwardly to engage the inner box tube  14  and thus join the inner box tube  14  with the outer box tube  12 , as previously described. 
     Various modifications can be made to the present invention without departing from the apparent scope hereof. 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 BOX TUBE CLAMPING SYSTEM PARTS LIST 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 10 
                 box tube clamping 
               
               
                   
                   
                 system 
               
               
                   
                 12 
                 outer box tube 
               
               
                   
                 12a 
                 upper panel 
               
               
                   
                 12b 
                 lower panel 
               
               
                   
                 12c-d 
                 side panels 
               
               
                   
                 14 
                 inner box tube 
               
               
                   
                 14a 
                 upper panel 
               
               
                   
                 14b 
                 lower panel 
               
               
                   
                 14c-d 
                 side panels 
               
               
                   
                 14e-f 
                 insertional paths 
               
               
                   
                 16 
                 variable geometry 
               
               
                   
                   
                 clamp 
               
               
                   
                 18 
                 elongated hole 
               
               
                   
                 22 
                 center wedge 
               
               
                   
                   
                 assembly 
               
               
                   
                 24 
                 left wedge 
               
               
                   
                   
                 assembly 
               
               
                   
                 26 
                 right wedge 
               
               
                   
                   
                 assembly 
               
               
                   
                 28 
                 bolt 
               
               
                   
                 30 
                 lock washer 
               
               
                   
                 32 
                 wedge plate 
               
               
                   
                 32a-b 
                 bevels 
               
               
                   
                 32c 
                 bottom surface 
               
               
                   
                 32d 
                 top surface 
               
               
                   
                 34 
                 post 
               
               
                   
                 36 
                 body hole 
               
               
                   
                 38 
                 wedge plate 
               
               
                   
                 38a-b 
                 bevels 
               
               
                   
                 38c 
                 bottom surface 
               
               
                   
                 38d 
                 top surface 
               
               
                   
                 40 
                 post 
               
               
                   
                 42 
                 threaded hole 
               
               
                   
                 44 
                 wedge plate 
               
               
                   
                 44a-b 
                 bevels 
               
               
                   
                 44c 
                 top surface 
               
               
                   
                 44d 
                 bottom surface 
               
               
                   
                 46 
                 post 
               
               
                   
                 48 
                 elongated body 
               
               
                   
                   
                 hole 
               
               
                   
                 50a-n 
                 gripping ridges 
               
               
                   
                 52 
                 installation 
               
               
                   
                   
                 spacer 
               
               
                   
                 54 
                 installation 
               
               
                   
                   
                 spacer 
               
               
                   
                 55 
                 slot 
               
               
                   
                 56 
                 arcuate surface 
               
               
                   
                 58 
                 wall extension 
               
               
                   
                 60 
                 wall extension 
               
               
                   
                 62 
                 space