Abstract:
A breakaway sign support system that is useful for supporting ground mounted signs located within zones that are vulnerable to vehicular impacts. A bracket assembly containing a combination of mounting plates and reinforcement plates bolted together is used to attach a sign post to a sign stub. The sign support system can be fabricated in the field without having to send measurements to a fabricator. The bracket assembly keeps the sign post stable but also allows for a clean break away upon impact.

Description:
[0001]    This application claims priority to U.S. Provisional Patent Application Ser. No. 60/880,645, entitled “BREAKAWAY SIGN SUPPORT SYSTEM,” filed on Jan. 16, 2007, the entire content of which is hereby incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    This invention pertains to a breakaway support system for signs, and particularly to an omni-directional breakaway system for supporting ground mounted signs located within zones that are vulnerable to vehicular impacts. 
         [0003]    Accident research and field experience have demonstrated that vehicles often leave the roadway and impact structures at high angles of incident. Breakaway sign posts have proven to be highly effective in reducing vehicle damage and occupant injury resulting from collision with highway marker signs. A variety of breakaway sign post constructions intended to meet safety requirements for highway installations have been used before for installation of highway traffic signs. 
         [0004]    Conventional breakaway systems are typically used between a relatively short section of base post that is set in a concrete base in the ground, and a longer section of sign post that extends upwardly above the ground from the base post and supports the sign. When a car collides with the sign post, the section of the sign post above the ground is typically sheared off or hinged over to allow the car to continue on its path with minimum damage to the vehicle and without injury to its occupants. Laws and regulations typically require that the base post extend no more than a few inches above the ground following a collision to avoid damage to fuel lines or penetration of the vehicle passenger compartment as the vehicle passes over the broken-off posts. 
         [0005]    It is important that a predictable and reliable breakaway attachment be provided between the post sections to insure that the sign post will break without imparting excessive force to the car or causing injury to its occupants, and to insure that the stub height of the base post does not cause damage to the vehicle as the vehicle passes over the base post following a collision. It is also important that such sign posts be capable of withstanding ambient wind loads normally encountered by highway sign installations. What is further needed is a breakaway attachment that provides for a predictable and omni-directional break regardless of the direction or angle of impact. 
       SUMMARY 
       [0006]    The present invention relates generally to support systems for signs In particular, the present invention relates to a breakaway support system for ground mounted signs located within roadside clear zones or other locations vulnerable to vehicular impacts. 
         [0007]    The support system is designed to break away quickly and cleanly upon impact, thus saving lives and reducing property damage costs. The support system can also be fabricated in the field, eliminating the need to take measurements to a fabricator. A user can verify the length needed, cut the post, attach the brackets, and mount to the ground stub, all in the field. This will save a great deal of time and money. The support system works with a standard fiberglass I-beam or steel I-beam and will retrofit to any existing I-beam stub in the ground. 
         [0008]    In addition to superior safety performance, the support system provides high structural load carrying capacity. New national signing standards specify increased sign sizes for visibility, in addition to increased wind load levels. These changes create a significant increase in structural demands on sign supports. The support system is designed to support a wide range of post sizes, up to and including the largest permitted by American Association of State Highway Transportation Officials (“AASHTO”). The flexibility built into the system provides many choices when selecting post types and sizes for specific applications. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  shows a side perspective view of one embodiment of the support system and the bracket assembly that has not been assembled; 
           [0010]      FIG. 2  shows a top view of one embodiment of the support system and the bracket assembly that has not been assembled; 
           [0011]      FIG. 3  shows a side perspective view of one embodiment of the support system and the bracket assembly that has been assembled; 
           [0012]      FIG. 4  shows a side view of one embodiment of the support system and the bracket assembly that has been assembled and mounted to a ground stub; and 
           [0013]      FIG. 5  shows a side perspective view of one embodiment of a mounting plate that is part of the bracket assembly. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0014]    Generally, the present invention relates to a breakaway sign support system which will break away cleanly upon impact and is ideal for areas vulnerable to vehicular impact. 
         [0015]    The support system can be configured in a variety of ways to support different sign configurations and post types. The high-strength coupling and L-bracket design provides increasing structural capacity as the size of the post increases. This unique feature offers unmatched load-carrying capacity, and accommodates many different post types for both single and multiple post configurations. 
         [0016]    For example, and without limitation, the support system can be used in association with 4 inch and 5 inch standard I-beam posts, as well as 6 inch, 8 inch, and 10 inch up to 21 inch wide flange I-beam posts. The I-beam posts can be made of fiberglass or steel. The support system can also be retrofitted to any existing I-beam stub that is already in the ground. 
         [0017]    Due to the unique design of the support system, users can fabricate the system in the field without having to take measurements to a fabricator. After verifying the length in the field, the user can cut the post, attach the brackets, and mount the system to the stub. This saves time and money by eliminating the need to use an off-site fabricator. 
         [0018]    No special tools or equipment are required to properly install and maintain the support system. All components are easily secured using the American Institute of Steel Construction (“AISC”) Turn-of-Nut Tightening method, which eliminates the torque requirement typical with other systems. 
         [0019]    Referring now to  FIG. 1 , one embodiment of the breakaway sign support system  10  is shown. The support system  10  utilizes a sign post  20  and a sign stub  30 . In this embodiment, both the sign post  20  and the sign stub  30  are in an I-beam configuration. The I-beam shaped sign post  20  includes a front post flange  22  and a rear post flange  24 , as well as a center post structural support  26 . The I-beam shaped sign stub  30  also includes a front stub flange  32 , a rear stub flange  34 , and a center stub structural support  36 . In a preferred embodiment, the sign post  20  is made of fiberglass or steel and the sign stub  30  is made of fiberglass or steel. Attaching the sign post  20  to the sign stub  30  is the bracket assembly  40 . The bracket assembly  40  does not include the sign post  20  and the sign stub  30  but does include various brackets, plates, and bolts used to connect the two. 
         [0020]    The bracket assembly  40  preferably includes a front post mounting plate  42  and a rear post mounting plate  44 . These mounting plates are in an L-bracket type shape in this embodiment. The front post mounting plate  42  is secured to the front post flange  22  through its front post mounting holes  46 , and the rear post mounting plate  44  is secured to the rear post flange  24  through its rear post mounting holes  48 . The front post mounting holes  46  match up with front post holes  28  and the rear post mounting holes match up with rear post holes  29 . These holes can accommodate standard bolts that can be secured with washers and nuts. Other attachment devices can also be used. In preferred embodiments, the front post mounting plate  42  also includes a front post stiffener plate  52 , and the rear post mounting plate  44  also includes a rear post stiffener plate  54 . The post stiffener plates act as a gusset or a support to add to the structural integrity of the bracket assembly  40 . 
         [0021]    The front post mounting plate  42  also preferably includes a front post mounting cleat  56 , and the rear post mounting plate  44  includes a rear post mounting cleat  58 . These mounting cleats contain front post connecting slots  62  and rear post connecting slots  64 , which can accommodate standard bolts, nuts, and washers for connection of the sign post  20  to the sign stub  30 . Sign stub  30  also includes a front stub mounting cleat  66  disposed on the front stub flange  32  and a rear stub mounting cleat  68  disposed on the rear stub flange  34 . In preferred embodiments, these stub mounting cleats can be further supported with stub stiffener plates, such as the rear stub stiffener plate  72 . The stub mounting cleats also contain connecting slots, the front stub connecting slots  74  and the rear stub connecting slots  76 . 
         [0022]    Disposed between the sign post  20  and the sign stub  30  is the bolt keeper plate  80 . The bolt keeper plate  80  has front bolt keeper holes  82  and rear bolt keeper holes  84 . When the bracket assembly  40  is assembled, a standard bolt can pass though a front post connecting slot  62 , a front bolt keeper hole  82 , and a front stub connecting slot  74  to hold the entire assembly together. Similarly, a bolt can pass through a rear post connecting slot  64 , a rear bolt keeper hold  84 , and a rear stub connecting slot  76 . 
         [0023]    For added stability, the bracket assembly  40  can also include a right side reinforcement plate  92  and a left side reinforcement plate  94  that can, in this embodiment, fit within the U-shaped void spaces on either side of the sign post. The right side reinforcement plate  92  has right side front reinforcement holes  96  that line up with the front post mounting holes  46  and the front post holes  28  on the right side of the sign post  20 . Thus, a standard bolt can pass through a front post mounting hole  46 , a front post hole  26 , and a right side front reinforcement hole  96  to ensure that the front post mounting plate  42  and the right side enforcement plate  92  are fastened to the sign post  20  and to each other to add stability. Similarly, a standard bolt can pass through a rear post mounting hole  48 , a rear post hole  29 , and a left side reinforcement hole  104  to attach the rear post mounting plate  44  and the left side reinforcement plate  94  to the sign post  20  and to each other. The right side rear reinforcement holes  102  also engage the rear post mounting holes  48 . 
         [0024]    Referring now to  FIG. 2 , a top view of one embodiment of the support system  10  and the bracket assembly  40  is shown. The sign post  20  is located in the center. When the support system  10  is assembled, front post mounting plate  42  will be attached to front post flange  22 . Front post mounting plate  42  also includes a front post mounting cleat  56  having front post connecting slots  62 . A front post stiffener plate  52  is also attached to the front post mounting plate  42  for added stability. To the left of the sign post  20  is a left side reinforcement plate  94 , and to the right side of the sign post  20  is a right side reinforcement plate  92 . These reinforcement plates also add stability to the bracket assembly  40  when all of the bolts are attached. Adjacent to the rear post flange  24  is the rear post mounting plate  44  having a rear post mounting cleat  58  with rear post connecting slots  64 . The rear post mounting plate  44  will be attached to the rear flange  44  when the bracket assembly  40  is assembled. The rear post mounting plate  44  also has a rear post stiffener plate  54  for added stability. 
         [0025]      FIG. 3  shows a side, angled view of one embodiment of the support system  10  in which the bracket assembly  40  has been assembled to connect the sign post  20  to the sign stub  30 . Rear post mounting plate  44  has been attached to rear post flange  24  and both side reinforcement plates with rear post bolts  112 . Right side reinforcement plate  92  is also attached to front post flange  22  and front post mounting plate  42  with front post bolts  110 . Rear post connecting bolts  120  pass through the rear post mounting cleat  58 , the bolt keeper plate  80 , and rear stub mounting cleat  68 . Although not shown in  FIG. 3 , front post connecting bolts also pass through the front post mounting cleat  56 , the bolt keeper plate  80 , and the front stub mounting cleat  66 . Rear post stiffener plate  54  and rear stub stiffener plate  72  provide added stability. Also, in preferred embodiments, any bolts, plates, or brackets attached as part of the support system can be welded to the post or stub for added stability. 
         [0026]      FIG. 4  shows a direct rear view of one embodiment of the support system  10  in which the bracket assembly  40  has been assembled to connect the sign post  20  to the sign stub  30 . The rear post mounting plate  44  is attached to the rear post flange  24  with rear post bolts  112 . A rear post stiffener plate  54  runs between the rear post mounting cleat  58  and the rear post mounting plate  44  and provides stability. A rear stub stiffener plate runs between the rear stub mounting cleat  68  and the rear stub flange  34  and provides stability. The sign post  20  is attached to the sign stub  30  by connecting bolts, illustrated in  FIG. 4  as rear post connecting bolts  120 . The rear post connecting bolts  120  pass through a flat washer  124 , the rear post mounting cleat  58 , another flat washer  124 , the bolt keeper plate  80 , the rear stub mounting cleat  68 , another flat washer  124 , and a connecting nut  122 . 
         [0027]    Further embodiments of the support system can include various modifications to the bracket assembly, the sign post, and the sign stub. For example, the connecting slots located in the mounting cleats on both the sign post and the sign stub can be holes rather than slots.  FIG. 5  shows an alternate embodiment for one of the mounting plates  200 . In this embodiment, the connecting bolts  202  are not visible as they pass through the mounting cleat  204 . In addition, particularly if the sign post is very large, several post bolts  206  can be located on the post mounting plates  200 . The portion of the mounting plate  200  that is meant to contact the sign post can also have a series of step-like levels of increasing thickness  208  to add stability.