Patent Publication Number: US-6708643-B2

Title: Portable airport traffic barricade

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates generally to barricades and, more particularly, to portable barricades used at airport facilities to separate aircraft from ground vehicles. 
     Because of construction and repair work conducted at operational airports, and for other reasons, it is often necessary to route aircraft and ground vehicle traffic in relatively close proximity. In such circumstances, portable barricades are often used to maintain safe separation between the aircraft and the ground vehicles. It is desirable that the barricades be relatively light to facilitate their transport and set up, while ensuring that the barricades remain operationally stable even when exposed to propeller wash or exhaust generated by the aircraft moving in close proximity. In the past, separate sand bags have been placed on the barricades, but the sand bags themselves are heavy and require additional time and labor when setting up the barricades. Additionally, sand bags often leak, discharging sand onto runways or adjacent airport traffic areas. 
     A need exists, therefore, for a truly portable barricade which can remain upright and operational when subject to high air flows from propeller-driven aircraft or from high velocity exhaust from jet aircraft. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a portable barricade for use in separating aircraft traffic and ground vehicles comprising an appropriately marked sign panel hanging from a horizontally extending frame member, the frame member and sign panel being supported by first and second pairs of legs that expand to form what is generally known as an A-frame barricade. The first and second pairs of legs are supported by two cross braces, the first having a tubular configuration and the second having a planar configuration. The barricade is positioned so that the side of the barricade having the tubular cross brace is adjacent the aircraft traffic, with the side having the planar cross brace adjacent the ground vehicle traffic. In this way, the airflow or exhaust generated by aircraft will exert a greater force on the planar cross brace than on the tubular cross brace, tending to maintain the barricade with its legs in an expanded, operational position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features, objects and advantages of the present invention will become apparent from the following description and drawings wherein like reference numerals represent like elements in several views, and in which: 
     FIG. 1 is a perspective view illustrating one preferred embodiment of the present invention; 
     FIG. 2 is a plan view illustrating the placement of the portable barricade at an airport facility between aircraft and ground vehicle traffic; 
     FIG. 3 is a partial exploded perspective view of a portion of the barricade illustrated in FIG. 1, showing details of the light mounting bracket; 
     FIG. 4 is a cross-sectional view taken along line  4 — 4  in FIG. 1; and 
     FIG. 5 is a view of the barricade shown in FIG.  1  and taken along line  5 — 5  of FIG. 2, illustrating the barricade&#39;s function when subject to aircraft generated airflow or exhaust. 
     FIG. 6 is a front view of a suitable sign panel for use in the portable barricade shown in FIG. 1; and 
     FIG. 7 is an enlarged segment view taken from FIG. 6 showing the arrangement of perforations in the sign panel. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A portable and collapsible barricade  10  is illustrated in FIGS. 1 and 2, being positioned to separate aircraft traffic from ground vehicle traffic. The barricade  10  includes a sign panel  12 , with suitable markings on both sides, hanging from a horizontal frame member  14 . The frame member and sign panel are supported by four legs; legs  16  and  18 , forming one pair, and being pivotally secured at one end of the frame member  14 , while legs  20  and  22  form the second pair and are pivotally secured at the other end of the frame member. Each pair of legs is moveable between a collapsed storage position and an expanded operational position. The expanded operational position is illustrated in FIGS. 1 and 5. Cross braces  30  and  32  are employed to provide structural support to the barricade  10  and to promote other advantages of the invention. One cross brace  30  has a generally tubular configuration and may be secured to legs  16  and  20  via U-bolts or any other well known securement technique. The other cross brace  32  has a generally planar configuration and is secured to legs  18  and  22  by bolts, or again by any conventional fastening mechanism. In accordance with the present invention, the tubular cross brace  30  generates less resistance to air flows or exhaust gases generated by nearby aircraft than does planar cross brace  32 . As a result, when the barricade is properly positioned between aircraft and other ground traffic, the aircraft air or jet blasts directed at the barricade (see generally Arrows  34  in FIG. 5) will generate greater forces on the planar cross brace  32  than on the tubular cross brace  30 , thereby maintaining the barricade&#39;s legs in their expanded, upright orientation. 
     Another feature of the invention is that, although the barricade  10  is capable of maintaining an upright operational position in the face of propeller wash or jet blast, it will readily collapse upon mechanical impact from aircraft or ground vehicles, minimizing damage to the barricade, aircraft or vehicle. 
     Preferably, the barricade employs a sign panel  12  approximately 2 ft. by 2 ft. in size and constructed from aluminum or other metal or rigid material. To minimize wind induced movement of the sign panel, it is preferably perforated. Quarter-inch diameter holes on three-eighths inch staggered centers have been found desirable in minimizing wind sway while maintaining optical clarity of the traffic markings. As shown in FIGS. 3 and 5, the sign panel  12  is also mounted to rotate vertically through 360° around frame member  14  and is maintained at a central position in barricade  10  by nesting the hanging brackets  40  within annular recesses  42  on frame  14 . 
     For a sign panel as described above, the tubular cross brace  30  is preferably constructed from four to five inch diameter PVC tubing, although other plastics or metals may also perform satisfactorily. A cylindrical configuration is preferred, but other tubing geometries, such as rectangular or triangular, may be employed, so long as the tubing dimension is minimized. In turn, the planar cross brace will preferably have minimum width of about five inches. It is also desirable to fill tubular cross brace  30  with a ballast material, such as sand. 
     Alternatively, the cross braces  30  and  32  may have other geometries provided the drag forces generated by the aircraft propeller wash or exhaust on the cross braces results in a net force tending to expand the barricade legs. It should be noted that the angular disposition of the cross brace  32  creates a lift force component acting on the barricade. 
     The ballast, for a barricade of the general size described above, will typically add about 25 pounds to the weight of the barricade, which in turn will have a total weight of about 40 pounds. Thus, the barricade is relatively lightweight, but will nonetheless withstand propeller wash and jet blasts from proximate aircraft. 
     As illustrated in FIGS. 1 and 3, the barricade  10  includes a pair of safety lights  50  which are mounted at opposed ends of the horizontal frame member  14  via mounting brackets  52 . The brackets  52  allow the lights to swivel when the barricade is collapsed, minimizing damage during transport or storage. The brackets  52  include tabs  54  each defining an internal shoulder or abutment  56  which act to limit the expansion of legs  16  and  18  and legs  20  and  22 . In addition, the shoulders  56  on each bracket  52  also act to self-align the lights in a generally horizontal orientation for proper optical positioning. 
     While the invention has been described with reference to the preferred embodiments thereof, it will be appreciated that numerous variations, modifications, and alternate embodiments are possible including the use of the apparatus with objects other than fasteners. Accordingly, all such variations, modifications, and alternate embodiments are to be regarded as being within the spirit and scope of the invention.