Abstract:
A sign bracket for over-road highway signs and other signs. The bracket is comprised of a first assembly attached to the sign and a second assembly attached to a support structure. A shear pin prevents relative movement between the first assembly and second assembly in its normal state. When sufficient pressure is exerted on the sign the shear pin shears and the first assembly is freed to rotate the sign approximately ninety degrees. The sign is essentially laid flat either face up from wind force striking the face of the sign or face down from wind striking the rear of the sign. When the sign is laid flat it produces substantially reduced wind resistance and the support structure remains intact. The sign may then easily re-erected by insertion of a new shear pin.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to sign brackets, and more particularly, to highway overhead sign brackets that are capable of withstanding high wind load forces by changing the angle of incidence of the wind relative to the sign. 
     2. Description of the Related Art 
     Several designs for sign brackets have been designed in the past. None of them, however, includes a device that allows a highway sign to shift to the horizontal under heavy wind load to reduce the stress on both the sign and support structure while remaining easy to re-erect after risk of damaging winds subside. 
     Applicant believes that the closest reference corresponds to U.S. Pat. No. 4,503,631 issued to Kelly. However, it differs from the present invention because the Kelly device does not allow easy adjustment of the shear pressure exerted onto the sign to allow the sign to freely move and permits dangerous swinging of the sign after it begins to move. Furthermore, the Kelly design requires significant structure above the sign that is unnecessary in Applicant&#39;s invention. 
     Other patents describing the closest subject matter provide for a number of more or less complicated features that fail to solve the problem in an efficient and economical way. None of these patents suggest the novel features of the present invention. 
     SUMMARY OF THE INVENTION 
     It is one of the main objects of the present invention to provide a sign bracket that will allow a sign and supporting structure to survive high wind loads, such as during a hurricane. 
     It is an object of the present invention to provide a sign bracket that allows the use of significantly lighter and more economical sign support structure because the sign will change profile at a predetermined wind speed and therefore will impart less stress onto the support structure. 
     It is another object of this invention to provide a uniform device that is scalable to effectively work with a wide variety of sign dimensions. 
     It is still another object of the present invention to provide a sign bracket that is easy to re-erect after a high wind event. 
     It is yet another object of this invention to provide such a device that is inexpensive to manufacture and maintain while retaining its effectiveness. 
     Further objects of the invention will be brought out in the following part of the specification, wherein detailed description is for the purpose of fully disclosing the invention without placing limitations thereon. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       With the above and other related objects in view, the invention consists in the details of construction and combination of parts as will be more fully understood from the following description, when read in conjunction with the accompanying drawings in which: 
         FIG. 1  represents a perspective view of multiple sign brackets holding a sign. 
         FIG. 2  shows an elevation view of a sign bracket in its normal configuration. 
         FIG. 3  illustrates a perspective view of a sign bracket after a front wind load. 
         FIG. 4  is a representation of a perspective view of a sign bracket after a rear wind load. 
         FIG. 5  is an exploded perspective view of the various components of a sign bracket. 
         FIG. 6  is an elevation view of a variation of a shear pin. 
         FIG. 7  is an elevation view of another variation of a shear pin. 
         FIG. 8  is a plan view of the device as it might be attached to a sign and a sign post. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings, where the present invention is generally referred to with numeral  10 , it can be observed that it basically includes a hub assembly  18 , a drum assembly  32 , a drum assembly  44  and a plate assembly  68 . 
       FIG. 1  shows the device  10  as it could be in actual use to support a sign  12 . Overhead highway signage is often displayed over a roadway to provide navigational information to passing motorists. The present invention relates to brackets that connect a sign  12  to a support structure  14 . A typical configuration includes a vertical support post  16  affixed to a horizontal support post  14 . The present invention is an improved bracket  10  that connects the sign  12  to the horizontal support post  16 . In some configurations two vertical support posts  16  connect at each end of the horizontal support bar  14  to span the roadway below and provide for a more robust sign support structure. 
     Now referring to  FIGS. 2 ,  3  and  4  where the device is shown assembled and in more detail. In these representations the device is shown to include, inter alia, bores  72 , tab  70 , tab  40 , shear pin bore  38 , fasteners  64 , disk  24 , flange  34 , swing arm  54 , bores  56 , shear pin bore  22 , drum  36  and fastener  60 . Generally, a pair of swing arms  54 , one on each side of the device, are affixed to a horizontal support  14  such as demonstrated in more clearly in  FIG. 8 . In a preferred configuration the swing arms  54  are affixed to the horizontal support  14  by means of bolts (not shown) that penetrate bores  56  and connect to a corresponding mounting means (example shown in  FIG. 8  and discussion below) on the horizontal support  14 . Alternative means to affix the swing arms  54  to the horizontal support could include rivets, welding, brazing, clamping or other commonly known methods of attaching metal to metal. 
     Tab  70  connects the device to a sign  12  by means of bolts (not shown) fit through bores  72  and the sign  12 . Alternative means to affix the tab  70  to the sign  12  could include rivets, welding, brazing, clamping or other commonly known methods of attaching metal to metal. 
       FIG. 2  shows the device configured for normal use with the tab  70  projecting from the flange  34  on the opposite side of the swing arms  54 . This configuration holds the face of the sign  12  substantially vertical so that it can be read by passing motorists. In actual use a shear pin  62  (shown in  FIG. 5 ) penetrates shear pin bore  38  to prevent rotational movement of the disk  24  relative to the flange  34 . Fastener  60  affixes swing arm  54  to disk  24 . Disk  24  is rigidly affixed to a first end of axle  20  and disk  26  is rigidly affixed to a second end of axle  20 . 
       FIG. 3  is an example an up safe mode of the device after the shear pin  62  has broken under wind load on the obverse of the sign  12  and the sign  12  has been permitted to fall back to face skyward above the device. Generally, tab  70 , flange  34  and tab  40  are immovable relative to each other. Similarly, swing arms  54  are immovably affixed one each to disk  24  and corresponding disk  26 . During the transition from normal use shown in  FIG. 2  to the up safe mode in  FIG. 3  the shear pin  62  fractures and the tab  70 , flange  34  and tab  40  rotate around disk  24  and disk  26  until tab  40  and tab  50  (shown in  FIG. 5 ) contacts the edge of swing arms  54  and prevents further rotation. The total relative rotation from normal mode to up safe mode is about plus ninety degrees. 
       FIG. 4  shows the device in a down safe mode after the shear pin  62  has broken under wind load to the reverse side of the sign  12  and the sign  12  has been permitted to fall forward to face toward the ground below the device. During the transformation from normal use shown in  FIG. 2  to down safe mode shown in  FIG. 4  the shear pin  62  fractures and the tab  70 , flange  34  and tab  40  rotate around disk  24  and disk  26  until tab  40  and tab  50  (shown in  FIG. 5 ) contacts the edge of swing arms  54  and prevents further rotation. The total relative rotation from normal mode to down safe mode is about minus ninety degrees. 
       FIG. 5  shows an exploded view of the device further clarifying interaction between the various components of the device and are shown to include in addition to other elements previously described, inter alia, an axle  20 , a disk  26 , a swing arm bore  28 , a swing arm bore  30 , bores  42 , bores  46 , a drum  48 , a tab  50 , a flange  52 , a bore  58 , fasteners  66 , plate  74  and bores  76 . Generally the device is comprised of a first assembly and a second assembly that are moveable relative to each other when the shear pin  62  is not connecting them together. The first assembly is affixed to the sign  12  and the second assembly is affixed to the horizontal support  14 . 
     The first assembly is comprised of, inter alia, the plate assembly  68  sandwiched between the drum assembly  32  and the drum assembly  44 . A multiplicity of fasteners  64  fit through bores  42 , bores  76  and bores  46  and are secured with fasteners  66 . Fasteners  64  and fasteners  66  could be bolts and nuts, respectively, or other means commonly used to connect metal to metal such as rivets, welds, brazing or clips. Drum assembly  32  is substantially identical to drum assembly  44 . 
     The second assembly is comprised of, inter alia, the hub assembly  18  and swing arms  54 . Generally, the hub assembly  18  is placed into the first assembly before the first assembly is bolted together. Then the swing arms  54  are affixed to the disk  24  and disk  26 , respectively. Fasteners  60  penetrate bores  58  on each of the swing arms  54  and are affixed to disk  24  and disk  26  at bore  28  and bore  30 , respectively. 
     To prevent relative movement between the first assembly and second assembly the shear pin  62  passes through bore  38  on the first assembly and bore  22  on the second assembly. Only when the torque between the first assembly and second assembly is sufficient to shear the shear pin  62  will the first assembly be able to rotate relative to the second assembly. Optionally a solid state lubricant may be present on the rim of the disk  24  to facilitate rotation and inhibit corrosion. The drawings show that a shear pin  62  is only present connecting drum assembly  32  and disk  24  but it should be recognized that an additional shear pin between drum assembly  44  and disk  26  could also be present or alternatively present. 
       FIGS. 6 and 7  show various features of alternative shear pin designs and include, inter alia, threads  78 , a shaft  80 , a head  82 , threads  84 , a shaft  86 , a key  80 , a key  89  and a head  90 . Alternative shear pins are shown to provide various shear pins with specific predetermined shear or break point. There are advantages of having common diameter shear pins with differing shear points in that only the shear pin differs for different applications and the balance of the device remains consistent. 
     In one variation the placement of the threads  78  on the shaft  80  are adjacent to the head  82 . If this variation is utilized with corresponding threads in shear pin bore  38  and would hold the shear pin in place and allow for easy replacement. Key  89  is optionally provided to allow for a precisely calibrated shear strength while maintaining a constant diameter of the shaft  80  and threads  78 . The dimensions of the key  89  may be varied to adjust the shear strength. Alternatively, threads  84  may be on the shaft  86  opposite the head  90  and could engage into threaded shear pin bore  22 . 
     To calibrate the force at which a shear pin will shear a key  88  is optionally provided. Generally the presence of a key  88  will reduce the force required to break the shaft  88 . The larger the key  88  relative to the shaft  88  the less force required to shear the shear pin. It should be appreciated that any shear pin design could have threads at either end of the shaft or no threads at all and optionally have a key present. The head  82  or head  90  is preferably a hex head but could also take other forms to permit easy installation and removal of a shear pin. 
       FIG. 8  is provided to demonstrate an example of how the device could be attached to a sign  12  and a horizontal support. A mount  92  and mount  94  are not elements of the present invention and are included only to show how the device could be used. Generally, the swing arms  54  are affixed to the mount  94  and the tab  70  is attached to mount  92  on the sign  12 . A nut and bolt combination or other means commonly used to attach two pieces of metal together may used to affix the swing arms  54  to the mount  94  and the tab  70  to the mount  92 . 
     A preferred variation of the invention provides a bracket for connecting a sign to a support structure comprising a first assembly that is attachable to a sign and a second assembly that is attachable to a support structure; said first assembly and said second assembly are rotatable around a common axis; a shear pin preventing relative movement between said first assembly and said second assembly; said shear pin having a predetermined shear point; when sufficient torque is applied between the first assembly and the second assembly said shear point is exceeded and the shear pin is broken permitting said first assembly to rotate substantially ninety degrees in the direction said torque is applied relative to said second assembly. 
     Another preferred variation of the invention provides a bracket for connecting a sign to a support structure comprising a first assembly and a second assembly; said first assembly affixable to said sign and said second assembly affixable to said support structure; said first assembly and said second assembly capable of rotation about a common axis; said first assembly having tabs that limit said rotation relative to said second assembly to substantially 180 degrees; a shear pin securing said first assembly&#39;s movement relative to said second assembly at substantially the mid-point between said 180 degrees of rotation; said shear pin shear-able at a predetermined torque between said first assembly and said second assembly thereby permitting said first assembly to rotate about said common axis relative to said second assembly. 
     Yet another preferred variation of the invention provides a sign bracket comprised of a first assembly and a second assembly; said first assembly further comprised of a first drum assembly, a second drum assembly and a plate assembly; said second assembly further comprised of a hub assembly and one or two swing arms; said hub assembly disposed between said first drum assembly, said second drum assembly and said plate assembly; said swing arm attached to a first end of said hub assembly and if present, a second swing arm attached to a second end of said drum assembly; said first assembly and said second assembly rotatable relative to each other about a common axis; a shear pin affixing said first assembly and said second assembly at a predetermined first position relative to each other; said first assembly further having a pair of tabs one each to limit the rotation of said swing arm(s) to substantially ninety degrees in either a first direction or second direction relative to said first position; said shear pin shear-able at a predetermined torque between said first assembly and said second assembly. 
     The foregoing description conveys the best understanding of the objectives and advantages of the present invention. Different embodiments may be made of the inventive concept of this invention. It is to be understood that all matter disclosed herein is to be interpreted merely as illustrative, and not in a limiting sense.