Patent Publication Number: US-2007098490-A1

Title: Low profile barriers

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This application is a continuation-in-part of U.S. patent application Ser. No. ______ filed on Oct. 24, 2005, which is incorporated herein by specific reference. 
    
    
     BACKGROUND OF THE INVENTION  
      1. The Field of the Invention  
      The present invention relates to barriers, and more particularly, portable, reusable, control barrier systems that can be used in delineating runways, airfield construction zones, and other construction sites.  
      2. The Relevant Technology  
      Control barriers are used in a variety of situations. For example, control barriers can be selectively positioned at special events or construction sites to help direct pedestrian and automobile traffic in a desired direction. Similarly, control barriers can be used at airports to delineate construction zones and direct ground traffic and taxiing aircraft in a desired direction. Alternatively, control barriers can be put up to help limit access to select areas. In yet other embodiments, control barriers can be put up to define an entertainment stage or the boundaries of a playing field. For example, control barriers can be used to define the boundaries of a soccer field or an ice skating rink.  
      Conventional control barriers have long comprised individual sawhorse type barriers or collapsible V-shape barricades. Such barriers, however, have limited use since they are generally lightweight and are thus easily tipped over or moved. This can be a problem particularly when used in conjunction with aircraft where the barriers cannot withstand the propeller wash or jet blast produced by aircraft and will be blown over or blown out of position. Other problems can arise due to the height of the barriers, which can cause damage to engines, wings, or other portions of aircraft that do not clear the height of the barrier. Furthermore, such barriers are typically not connected and often have spaces or gaps extending therethrough. As such, it is possible for individuals or ground equipment to either slip between or through the barriers.  
      Other barriers comprise various gates or walls that are mechanically assembled. Such barriers, however, require extensive time to assemble and disassemble. In yet other alternative embodiments, concrete barriers have been used. Although concrete barriers are not easily tipped over and can withstand the propeller wash or jet blast of aircraft, such barriers are extremely heavy. As such, they are difficult to move and place in, desired locations. Often, special equipment such as fork lifts or cranes are required. Furthermore, concrete barriers can be both difficult and expensive to move over large distances and require a large area to store. Concrete barriers can also be dangerous in that they are rigid and non-forgiving when impacted by a person, car, or taxiing aircraft.  
      In one attempt to overcome some of the above problems, plastic barriers have been made. The plastic barriers are hollow and can be filled with water for stabilizing. Although an improvement, existing plastic barriers also have several limitations. For example, plastic barriers are typically large and bulky. As a result, they are not easily stacked and require large areas to store and transport. Furthermore, conventional plastic barriers are typically too large to meet the strict requirements of being placed on the taxiway or runway of an airport.  
      In view of the foregoing, it would be desirable to have barriers that solved the foregoing problems.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      Various embodiments of the present invention will now be discussed with reference to the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope.  
       FIG. 1  is a top perspective view of one embodiment of a barrier of the present invention;  
       FIG. 2  is a bottom perspective view of the barrier shown in  FIG. 1 ;  
       FIG. 3  is a cross-sectional front view of the ends of a pair of barriers shown in  FIG. 1  coupled together;  
       FIGS. 4-6  are top plan views of a pair of barriers shown in  FIG. 1  coupled together at various angles of connection;  
       FIG. 7  is a perspective view of one end of the barrier shown in  FIG. 1  showing an alternative engaging mechanism;  
       FIG. 8  is a cross-sectional front view of a pair of barriers shown in  FIG. 1  stacked together for storage or transport;  
       FIG. 9  is a top perspective view of an alternative embodiment of a barrier according to the present invention;  
       FIG. 10  is a bottom perspective view of the barrier shown in  FIG. 9 ;  
       FIG. 11  is a top perspective view of another alternative embodiment of a barrier according to the present invention;  
       FIG. 12  is a bottom perspective view of the barrier shown in  FIG. 11 ; and  
       FIG. 13  is a bottom perspective view of an alternative embodiment of a light that can be mounted on the barrier shown in  FIG. 1 .  
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Depicted in  FIGS. 1 and 2  is one embodiment of an inventive barrier  10  incorporating features of the present invention. Barrier  10  comprises a housing  12  having an interior surface  14  bounding a chamber  16  that is adapted to receive a ballast. As used in the specification and appended claims, the term “ballast” is broadly intended to include any materials which can be poured into internal chamber  16 . By way of example and not by limitation, the ballast can include water, salt water, non-freezing fluids, sand, rock, cement, concrete, and the like.  
      Housing  12  comprises a central body  18  having a floor  20  and a longitudinal axis  22  extending between a first end  24  and an opposing second end  26 . Central body  18  further comprises opposing side walls  28  and  30  extending between floor  20  and a top wall  32 . End walls  34  and  36  extend between at least a portion of side walls  28  and  30  at first end  24  and second end  26 , respectively. Housing  12  further includes a first projection  38  and a second projection  40  projecting outward from the first and second ends  24  and  26 , respectively, along the longitudinal axis  22 .  
      Side walls  28  and  30  of central body  18  are depicted as being substantially rectangular. Side walls  28  and  30  are substantially parallel to each other and both are substantially perpendicular to top wall  32  and floor  20 . Thus, when floor  20  is horizontally disposed, side walls  28  and  30  are substantially vertically disposed and top wall  32  is substantially horizontally disposed. Thus, barrier  10  substantially forms a square or rectangle when viewed along the longitudinal axis  22 . In alternative embodiments other shapes can be formed.  
      Barrier  10  can vary in height, width, and length. In one embodiment barrier  10  has a maximum height extending between floor  20  and top wall  32  that is typically in a range between about 6 inches to about 20 inches with about 8 inches to about 12 inches being more common. Barrier  10  has a maximum width extending between opposing side walls  28  and  30  that is typically in a range between about 6 inches to about 20 inches with about 8 inches to about 12 inches being more common. Finally, barrier  10  has a maximum length extending between the terminal ends of projections  34  and  40  in a range between about 80 inches to about 120 inches with about 90 inches to about 110 inches being more common. Other dimensions can also be used. The size of barrier  10  is in part dictated by the intended use. For example, use of barrier  10  at an airport runway or taxi area requires that barrier  10  be sufficient size so that when internal chamber  16  is filled with a ballast, barrier  10  has sufficient weight to prevent unwanted movement when subject to propeller wash or jet blast of an aircraft. As such, barrier  10  is typically sized to that internal chamber  16  can hold at least 30 gallons of water. In other embodiments, internal chamber  16  can hold at least 35 gallons of water or at least 40 gallons of water. Other sizes can also be used.  
      In one embodiment of the present invention, at least a portion of one or both of side walls  28  and  30  can be sloped. For example, in the embodiment depicted, side wall  28  has a sloped portion  42  that is recessed within side wall  28  and is substantially rectangular. In other embodiments, other shapes can be used. Slope portion  42  typically comprises at least 70% of side wall  28  and more commonly at least 80% or at least 90%.  
      In the embodiment depicted, sloped portion  42  is sized so that reflective tape  44 , such as a high intensity reflective sheeting, can be attached thereto. Alternatively, a reflective coating can be painted on or otherwise attached to sloped portion  42 . Sloped portion  42  angles inward toward side wall  30  as sloped portion  42  rises toward top wall  32  to reflect light upward toward a pilot when the pilot is many feet above the ground in an airplane cockpit. The slope is such that the distance between sloped portion  42  and side wall  30  is greatest near floor  20  than near top wall  32 . For example, in the embodiment depicted, sloped portion  42  forms an angle θ of about three degrees relative to vertical. In alternative embodiments, angle θ can be in a range between about 2° to about 15° with about 2° to about 10° or about 2° to about 5° being more preferred. Other angles can also be used. It is appreciated that side wall  30  can include a sloped portion  46  in like manner to side wall  28 . Thus, in other embodiments sloped portions  42  and  46  can be disposed in parallel planes, can each slope in intersecting planes, or one wall can be vertical while the other wall slopes relative thereto.  
      One or more brackets can be mounted to barrier  10  for various purposes. For example, a bracket can be mounted which upwardly projects from top wall  32  to be used in mounting peripheral equipment such as a barrier light to barrier  10 . Depicted in the embodiment shown in  FIG. 1  is a bracket  48  attached to top wall  32 , which is used to secure a barrier light  50  to barrier  10 . Barrier light  50  comprises a housing  52  in which a battery is disposed and a lens  54  in which a light filament is disposed. Barrier light  50  can have a variety of other configurations. Bracket  48  is made of metal, but other materials may alternatively be used, such as hard plastic. An aperture  56  is formed in bracket  48  to aid in securing light  50  to barrier  10 . Aperture  56  can be a hole, a slit, or other type of opening.  
      In some embodiments, brackets  48  are attached to barrier  10  within recesses formed in top wall  32 . For example, depicted in  FIG. 1 , a first recess  58  and a second recess  60  are formed on top wall  32  of central body  18 . Recesses  58  and  60  are each sized to at least partially receive barrier light  50 . In the depicted embodiment, recesses  58  and  60  are generally rectangular shaped although other shapes can also be used. Recesses  58  and  60  are each bounded by a floor  62  and a perimeter sidewall  64  extending between the top surface of top wall  32  and floor  62 . Floor  62  has a circular indent  168  formed therein that can receive a cylindrical handle for a rotating light that mounts onto bracket  48 .  
      Specifically, depicted in  FIG. 13  is a bottom perspective use of a rotating light  170 . Light  170  comprises a substantially cylindrical handle  172  having a first end  174  and an opposing second end  176 . A substantially cylindrical lens  178  is mounted on second end  176  of handle  172 . A light bulb is disposed within lens  178  and is adapted to continuously rotate in a 360 degree pattern. A substantially U-Shaped clamp,  180  is mounted on handle  172 . Clamp  180  has a closed first end  182  and a forked second end  184 . A bolt  186  extends across forked second end  184  so as to secure clamp  180  onto handle  172 .  
      A mounting bolt  188  extends through first end  182  of clamp  180 . During mounting, first end  174  of handle  172  is received within circular indent  168  formed on one of recess  58  or  60  of barrier  10  ( FIG. 1 ). Mounting bolt  188  extends through aperture  56  on bracket  48  so that first end  182  of clamp  180  biases against bracket  48 . A nut  190  and washer  192  are then advanced along mounting bolt  188  and tightened against bracket  48  on the opposing side of clamp  180 , thereby securing light  170  to bracket  48 . It is appreciated that light  170  can be operated by a battery and/or a solar cell.  
      In the embodiment depicted in  FIG. 9 , bracket  48  is L-shaped having a base  49  and an upright  51  orthogonally projecting therefrom, aperture  56  being formed on upright  51 . Base  49  attaches to floor  62  of recess  60 . Upright  51  projects up from recess  60  and is used to secure light  50  to barrier  10 . Base  49  is riveted to floor  62  of recess  60  using two rivets  66 , thereby securing bracket  48  with recess  60 . Other fastening methods can alternatively be used to fasten bracket  48  to barrier  10 , such as screws, bolts, clips, Velcro or other known fastening methods. A bracket  48  can be attached to recess  58  in like manner.  
      Returning to  FIG. 1 , light fixture  50  can be secured to bracket  48  using any conventional methods such as screws, bolts, clips, Velcro or other known fastening methods. In the embodiment depicted, a bolt  68  having an enlarged head is selectively passed through aperture  56  so as to engage housing  52 , thereby securing barrier light  50  with bracket  48  within recess  60 . As will be discussed below in greater detail, bracket  48  can also be configured to allow stacking and coupling of two barriers  10  while brackets  48  remain attached to barriers  10 .  
      Depicted in  FIG. 2  is the exterior surface of floor  20  of central body  18  according to one embodiment. A pair of forklift channels  70  are recessed on floor  20  and extend between side walls  28  and  30 . Fork lift channels  70  are configured to receive the tines of a fork lift such that, if desired, barrier  10  can be moved by a fork lift even if filled with ballast. Means can also be provided for increasing the coefficient of friction of barrier  10  by securing pads or other similar devices to floor  20  as described in U.S. Pat. No. 6,086,285, which is incorporated herein by reference (hereinafter “the &#39;285 patent”).  
      In one embodiment of the present invention, means are provided for filling internal chamber  16  with ballast. By way of example and not by limitation, as depicted in  FIG. 1 , internal chamber  16  communicates with the exterior through an opening  72  located on top wall  32 . Opening  72  can be selectively closed or sealed by a cap (not shown). A threaded insert can be molded, welded, or otherwise attached to opening  72  to allow the cap to be screwed onto barrier  10 . In alternative embodiments, opening  72  can be positioned at other locations on barrier  10 . Means are also provided for selectively draining ballast from barrier  10 . By way of example and not by limitation, a drain hole  74  extends through side wall  28  adjacent floor  20 . Drain hole  74  can be threaded or a threaded insert can be attached thereto. A plug (not shown) can be screwed into or otherwise attached to drain hole  74  for sealing drain hole  74  closed. In alternative embodiments, drain hole  74  can also be positioned at other locations on barrier  10 . To help prevent the plug from accidentally being knocked out of drain hole  74 , drain hole  74  is preferably positioned within a recess  78  formed on side wall  28 .  
      Upwardly projecting from floor  20  of barrier  10  is a substantially conical post  80 . Post  80  is vertically aligned with opening  72  on top wall  32  of barrier  10  (see  FIG. 8 ). Post  80  is configured to be received in the end of a hollow pole such as a flag pole, support pole, or any other type of pole that is passed down through opening  72 . As a result of post  80  being substantially conical, post  80  can be snugly received within a variety of alternative pole sizes. In alternative embodiments, post  80  can be configured to receive different pole configurations. Further details concerning possible pole configurations that can be used with the present invention are given in the &#39;285 patent.  
      As mentioned above, housing  12  further includes a first projection  38  and a second projection  40  projecting longitudinally outward from first and second ends  24  and  26  of central body  18 , respectively. Projections  38  and  40  are configured such that for identical housings  12  the first projection  38  of one housing can overlap the second projection  40  of the other housing while the floor of both housings are resting on a common support surface, as discussed in further detail below.  
      With continued reference to  FIGS. 1 and 2 , first projection  38  comprises a top surface  82  and an opposing bottom surface  84  with a perimeter sidewall  86  extending therebetween. In the embodiment depicted, top surface  82  of first projection  38  lies in the same plane as top wall  32  of central body  18  and is thus horizontally displaced. Top surface  82  alternatively can lie in a different plane than top wall  32 . Bottom surface  84  projects longitudinally outward from first end wall  34  on first end  24  and is substantially parallel to top surface  82  and thus horizontally disposed in the embodiment depicted. Perimeter sidewall  86  is substantially vertical as it extends between top surface  82  and bottom surface  84 . First projection  38  is rounded on a distal end such that the end is substantially semi-circular when viewed from a position perpendicular to bottom surface  84  of first projection  38 . In the embodiment depicted one end of sidewall  86  attaches to central body  18  and lies in the same vertical plane as side wall  28  and the other end attaches to central body  18  and lies in the same vertical plane as side wall  30 .  
      Second projection  40  comprises a top surface  88  and an opposing bottom surface  90  with a perimeter sidewall  92  extending therebetween. In the embodiment depicted, bottom surface  90  of second projection  40  lies in the same plane as floor  20  of central body  18  and is thus horizontally displaced. Bottom surface  90  alternatively can lie in a different plane than floor  20 . Top surface  88  projects longitudinally outward from second end wall  36  on second end  24  and is substantially parallel to bottom surface  90  and thus horizontally disposed in the embodiment depicted. Perimeter sidewall  92  is substantially vertical as it extends between top surface  88  and bottom surface  90 . Second projection  40  is rounded on a distal end such that the end is substantially semi-circular when viewed from a position perpendicular to top surface  88  of second projection  40 . In the embodiment depicted one end of sidewall  92  attaches to central body  18  and lies in the same vertical plane as side wall  28  and the other end attaches to central body  18  and lies in the same vertical plane as side wall  30 .  
      Turning to  FIG. 3  in conjunction with  FIGS. 1 and 2 , first and second projections  38  and  40  are configured so that the bottom surface  84  of first projection  38  is disposed either in substantially the same plane as top surface  88  of second projection  40  or is disposed above top surface  88  of second projection  40 . The term “above” is defined as being a further distance away from floor  20 . As depicted in  FIG. 3 , because bottom surface  84  is either in the same plane as or above top surface  88 , the first projection  38  of one housing  10 A can overlap the second projection  40  of another identical housing  10 B while floor  20  of central body  18  of both housings are resting on a common support surface. First projection  38  and second projection  40  are also configured so that for identical housings  10 A and  10 B, one of the housings can be selectively positioned relative to the other housing over an angle formed between the longitudinal axis  22  of the one housing and the longitudinal axis  22  of the other housing in a wide range of angles, as shown in  FIGS. 4-6  and discussed in more detail below.  
      In one embodiment of the present invention means are provided for mechanically engaging first projection  38  of one barrier with second projection  40  of an identical housing in a releasable fashion when first projection  38  of one of the barriers is overlapping second projection  40  of the other barrier. By way of example and not by limitation, the means for mechanically engaging can comprise one or more engagers projecting from one of the projections  38 ,  40  and one or more pockets recessed on the other projection  38 ,  40 , the pockets being configured to receive the engagers of an identical barrier. For example, depicted in the embodiment of  FIGS. 1 and 2  is a pair of engagers  94  projecting from bottom surface  84  of first projection  38  and a plurality of pockets  96  formed on top surface  88  of second projection  40 . Each engager  94  is substantially similarly sized and shaped, and the distance between the center of the pair of engagers  94  is shown as d 1 .  
      The embodiment depicted includes eight pockets  96 . In other embodiments the number of pockets can be six or ten or any other number. The plurality of pockets  96  are configured to receive a pair of engagers  94  disposed on a separate identical barrier. Each pocket  96  is formed in top surface  88  to be able to receive a single engager  94 , as shown in  FIG. 3 . The plurality of pockets  96  are disposed in a substantially circular pattern having a second diameter d 2  substantially equal to the distance d 1  between engagers  94 , and each pocket  96  has a matching pocket  96  diametrically opposed to it on the opposite side of the circle (for example,  96 A and  96 B). This allows each pair of pockets  96  to be able to receive the pair of engagers  94 . As shown in  FIG. 3 , two identical barriers  10 A and  10 B are situated such that first projection  38  of barrier  10 B overlaps second projection  40  of barrier  10 A. The pair of engagers  94 A and  94 B are received in the pair of pockets  96 A and  96 B.  
      Returning to  FIG. 1 , there are four pairs of diametrically opposed pockets  96  formed in top surface  88  of second projection  40  in the embodiment depicted. This allows angles of multiples of 45 degrees to be able to be formed between the two engaged barriers  10 A and  10 B when engaged, as shown in  FIGS. 4-6 . To receive the pair of engagers  94  in a different pair of pockets  96 , first projection  38  of second barrier  10 B is lifted off second projection  40  of first barrier  10 A until no engagers  94  are received in any pockets  96 . Second barrier  10 B is then rotated with respect to first barrier  10 A until the engagers  94  on first projection  38  of barrier  10 B become vertically aligned with another pair of pockets  96  on second projection  38  of barrier  10 A. First projection  38  of barrier  10 B is then lowered onto second projection  38  of barrier  10 A, causing the different pair of pockets  96  to receive the pair of engagers  94 .  
      Turning to  FIG. 7 , a single annular pocket  98  can be used instead of a plurality of individual pockets  96  to receive engagers  94 . In this regard a singe engager  94  can also be used. Annular pocket  98  is formed in top surface  88  of second projection  40 . Pocket  98  forms a continuous ring recessed on top surface  88  and has a diameter d 3  substantially equal to the distance d 1  between engagers  94 . Pocket  98  comprises a side wall  100  that curves down from top surface  88  at an inner edge  102  and returns back to the surface at an outer edge  104 , defining the pocket. The cross-sectional shape of pocket  98  substantially mirrors the shape of engagers  94  so that pocket  98  can receive the pair of engagers  94  or a single engager  94 .  
      Because annular pocket  98  is a continuous channel, engagers  94  can be received by pocket  98  at any location around pocket  98 , thus allowing a continuum of angles to be formed between the engaged barriers. In the depicted embodiment, the range of angles that can be formed between two engaged barriers is about +90° to about −90°. Rotating barrier  10 B with respect to barrier  10 A is easier than when using individual pockets  96 , depicted above. To receive the pair of engagers  94  in a different location within pocket  98 , first projection  38  of second barrier  10 B is only slightly lifted, then rotated with respect to first barrier  10 A until the desired angle is obtained. First projection  38  of barrier  10 B is then lowered onto second projection  38  of barrier  10 A, causing the pair of engagers  94  to be received in a different location within pocket  98 .  
      In view of the foregoing, projections  38  and  40  and the means for engaging are formed so that a selective angle α can be formed between the longitudinal axis  22  of each of the coupled barriers  10 . Some of these angles are shown in  FIGS. 4-6 . For example, in  FIG. 5  angle α is shown at +45 degrees and can also extend to −45 degrees. In  FIG. 6 , the angle α is shown a +90 degrees and can also extend to −90 degrees. Here it is appreciated that by increasing the number of pockets  96 , barriers  10  can be set at a larger number of predefined angles. Likewise, by using annular pocket  98 , barriers  10  can be set at any defined angle. In addition, by moving end walls  34  and  36  back, angle α can be made larger than 90 degrees. For examples, barriers  10  can be formed to extend over an angle of at least +120 degrees to −120 degrees.  
      Although engagers  94  have been disclosed as being disposed on bottom surface  84  of first projection  38  and pockets  96  have been disclosed as being disposed on top surface  88  of second projection  40 , it is appreciated that in alternate embodiments, engagers  94  and pockets  96  can be disposed on the opposite surface. In other words, engagers  94  can alternatively be disposed on top surface  88  of second projection  40  and pockets  96  can alternatively be disposed on bottom surface  84  of first projection  38 . Also, although the preceding discussion discloses a pair of engagers being received by different pairs of pockets within a plurality of pockets, it is appreciated that the present invention can also be accomplished by having only a single pair of pockets. The present invention can also be accomplished using only a single engager that is received within a single pocket, including a single engager received within one of a plurality of pockets or by three or more engagers.  
      In an alternative embodiment of the means for mechanically engaging, a fastener can connect barriers  10  together. This alternative means can be used in place of or in conjunction with means that use engagers and pockets as described above. For example, returning to  FIG. 3  in conjunction with  FIGS. 1 and 2 , a kiss-off  106  is disposed on first projection  38  of barrier  10 . Kiss-off  106  extends between top surface  82  and bottom surface  84 . Kiss-off  106  comprises a top inset  108  that projects from top surface  82  into chamber  62  toward bottom surface  84 . Top inset  108  has an outside face  110  and an inside face  112 . Outside face  110  bounds a recessed, blind pocket  114  on top surface  82  while inside face  112  communicates with chamber  62 . Kiss-off  106  also comprises a bottom inset  116  that projects from bottom surface  84  into chamber  62  toward top surface  82 . Bottom inset  116  has an outside face  118  and an inside face  120 . Outside face  118  bounds a recessed blind pocket  122  on bottom surface  84  while inside face  120  communicates with chamber  62 .  
      As shown in  FIG. 3 , a portion of top inset  108  and a portion of bottom inset  116  are connected together within chamber  62  such as by being integrally molded together at a joint  124 . Joint  124  is encircled by chamber  62 . A hole  126  is formed through joint  124  allowing pocket  114  to communicate with pocket  122 , creating a passage  128  extending from top surface  82  to bottom surface  84 . An elongated fastener  130 , such as an eyebolt, can be extended down through passage  128  and project below bottom surface  84  of first projection  38 .  
      Means for receiving fastener  130  can be included in second projection  40  to secure fastener  130  and thus secure first projection  38  of one barrier to second projection  40  of another barrier. As shown in  FIG. 3 , a socket  132  is formed within top surface  82  of second projection  40 . Socket  132  is configured to receive a threaded insert  134  into which a screw or bolt can be screwed. Insert  134  can be directly molded into barrier  10  or can be subsequently secured within socket  132 . As a result, when projection  38  is centrally overlapping projection  40 , fastener  130  can be passed through projection  38  and screwed into threaded insert  134 , thereby securing first projection  38  of one barrier to second projection  40  of another barrier. It is appreciated that a variety of different coupling techniques can be used to connect fastener  130  to projection  40 . This engagement help prevent unwanted separation between the barrier  10  when subject to high loads, such as the propeller wash or jet blast from an aircraft.  
      If a fastener  130  is used in conjunction with engagers  94  and pockets  96  in engaging two identical barriers  10 A and  10 B, the barriers  10 A and  10 B are first engaged using engagers  94  and pockets  96 , as described above. Once the two barriers  10 A and  10 B are engaged in a desired rotation, fastener  130  is securely attached through passage  128  within first projection  38  of barrier  10 B to the means for receiving the fastener within the top surface  88  of second projection  40  of barrier  10 A, which is the threaded insert  134 .  
      In one embodiment of the present invention means are provided for mechanically mating a pair of barriers together for transport and/or storage. Turning to  FIG. 8  in conjunction with  FIGS. 1 and 2 , by way of example and not by limitation, projecting from top wall  32  are a pair of spaced apart tenons  138  and  140 . In the depicted embodiment, each tenon comprises an outwardly projecting ring  142  that terminates at an end wall  144  and encircles a cavity  146 . A pair of spaced apart mortises  148  and  150  are formed on floor  20  in alignment with tenons  138  and  140 . Tenons  138  and  140  are configured complementary to mortises  148  and  150 , respectively. Each mortise  148  and  150  comprises an annular wall  152  inwardly projecting from floor  20  that terminates at a recessed end wall  154 . A frustum  156  centered on end wall  154  projects out from end wall  154 , terminating at or about the same plane as floor  20 . The frustum  156  is sized and shaped to be able to be received within cavity  146  of the corresponding tenon  138  or  140  on top wall  32  of a separate identical barrier.  
      As depicted in  FIG. 8 , by seating a second barrier  10 B on top of barrier  10 A and mating top wall  32  of barrier  10 A to floor  20  of barrier  10 B, tenons  138  and  140  of barrier  10 A are received within corresponding mortises  148  and  150 , respectively, of barrier  10 B. As such, barriers  10 A and  10 B are mated together. The overall mated structure has a substantially parallelepiped configuration. As a result, the mated barriers  10 A and  10 B are easily stacked for transport or storage. In alternative embodiments, tenons  138  and  140  and mortises  148  and  150  can be a variety of alternative configurations and need only be constructed so that they mate together.  
      In some embodiments, a port  160  can centrally extend through end wall  144  of one or both of mortises  148  and  150  so as to communicate with internal chamber  16 . Elongated members such as poles, flags, guide rails, sign posts or others support structures can be passed down through one or both ports  160  so as to be supported by barrier  10 . The bottom end of the elongated member can be received within a pocket  162  formed on the interior surface of each mortise  148  and  150  to further support the elongated members.  
      In the embodiment depicted, barriers  10 A and  10 B are configured so that when mated the top surface and bottom surface of the assembled barriers are substantially flat except for tenons  138  and  140  that receive mortises  148  and  150 . This enables groups of assembled barriers to be easily and compactly stacked on top of and adjacent to one another for efficient storage and/or transport.  
      As described above, one or more brackets  48  can be mounted on top wall  32  of barrier  10  and upwardly project therefrom. Also as described above, a pair of fork lift channels  70  can extend between side walls  28  and  30  and along floor  20 . To allow stacking of barriers  10  without removing brackets  48 , each bracket  48  can be sized and positioned on top wall  32  to be aligned with one of the pair of fork lift channels  70  so at least a portion of the bracket  48  fits within the fork lift channel  70  when top wall  32  is seated against floor  20  of another identical barrier. If the brackets  48  are mounted within recesses formed on top wall  32 , the recesses can also be aligned with the forklift channels  70 . For example, as depicted in  FIGS. 1 and 8  recesses  58  and  60  are vertically aligned with forklift channels  70  which allows the stacking of barriers  10  without removing brackets  48 . Specifically, recesses  58  and  60  are positioned on barrier  10 A such that when second barrier  10 B is stacked on top of first barrier  10 A for transport or storage, recesses  58  and  60  of the first barrier  10 A are longitudinally aligned with forklift channels  70  of the second barrier  10 B. This allows brackets  48  attached to first barrier  10 A to be received within forklift channels  70  of second barrier  10 B.  
      Barrier  10  is typically made of a resiliently deformable polymeric material having strong, semi-rigid, and energy absorbing properties. Such materials include linear or cross-linked plastics that will deform under pressure but will not fail in a brittle manner. Examples of conventional polymeric materials include polyethylene (including High Density Polyethelene (HDPE)), polyvinylchloride, nylon, polycarbonate, and polypropylene. Additives such as dyes, pigments, and reinforcements, such as fibers, can also be added to the material. Florescent dies can be added to help barriers  10  glow at night for better direction of traffic. In one embodiment, it is preferred that barrier  10  be made from a recyclable plastic such as polyethylene or HDPE. This enables old or broken barriers to be ground down and recycled into new barriers.  
      Barrier  10  is typically made by blow molding. Of course, other molding processes, such as rotational molding, injection molding or die molding, can also be used. In the depicted embodiment, an opening  158  is formed on the second projection  40  ( FIG. 2 ) to allow air to be blown into the barrier during the molding process to force the plastic material to fill the edges of the mold as the barrier is being formed. A fitting can be formed within sidewall  92  of second projection  40  to aid in this process. Opening  158  can be closed by a plug. Independent of the method used, it is generally desirable that barrier  10  have a substantially uniform thickness T, as shown in  FIG. 3 , so as to minimize shrink deformation. In one embodiment, barrier  10  has a thickness T in a range between about 0.2 cm to about 1.5 cm with about 0.3 cm to about 0.8 being more common. The thickness is chosen to optimize desired deflection and required strength properties. Other dimensions can also be used.  
      Depicted in  FIGS. 9 and 10  is an alternative embodiment of a barrier  200  according to the present invention wherein like elements between barriers  10  and  200  are identified by like reference characters. Barriers  10  and  200  are substantially similar except that instead of having a plurality of pockets  96  disposed on top surface  88  of second projection  40 , barrier  200  has a single pocket  202  that is recessed within top surface  88 . Pocket  202  has a floor  204  that is recessed within top surface  88  and a perimeter sidewall  206  extending between top surface  88  and floor  204 . Pocket  202  comprises a center section  208  and a plurality of arms  210  radially extending outward from center section  208 . Similar to the plurality of pockets  96  of barrier  10 , each arm  210  has a matching arm  210  diametrically opposed to it on the opposite side of center section  208  (for example,  210 A and  210 B). This allows each pair of arms  210  to be able to receive the pair of engagers  94  that project down from first projection  38 . Engagers  94  a can also be shaped accordingly to allow a snug fit within arm  210 .  
      Depicted in  FIGS. 11 and 12  is another alternative embodiment of a barrier  220  according to the present invention wherein like elements between barriers  10  and  220  are identified by like reference characters. Barriers  10  and  220  are substantially similar except that barrier  220  contains no engagers or pockets on either projection  38  or  40 . The first projection  38  of barrier  220  can still overlap the second projection  40  of an identical barrier  220 , but the engagement is strictly by use of fastener  130  ( FIG. 3 ) that extends through passage  128  on first projection  38  and engages with insert  134  on second projection  40 , thereby securing the barriers together as previously discussed.  
      As mentioned above, additional features which can be incorporated into the present invention are disclosed in the &#39;285 patent.  
      In view of the foregoing, it is appreciated that various embodiments of the present invention have a number of unique benefits. For example, select embodiments provide an engaging means in which one end of the barrier can overlap the end of another barrier, forming an almost continuous wall. By using engagers that are received within pockets, a solid connection is made between barriers that prevents unwanted movement or rotation of one barrier relative to the other. Furthermore, use of fastener  130  prevents unwanted separation of the barriers. By providing tenons and mortises on the barriers and aligning attached brackets with fork lift channels, select embodiments of the current invention allow for easier stacking, while allowing the brackets to remain attached to the barrier. This saves time and money when transporting or storing the barriers.  
      A number of advantages are realized when used in an airport setting. For example, in some embodiments a portion of the side wall is sloped upward, which allows pilot to more easily see any reflective tape or coating on the sloped portion of the side wall, thus providing a safer airport construction environment. The low profile nature of the barriers helps to ensure that the barriers will not obstruct or damage planes while still providing necessary guidance. In addition, the barriers are of sufficient size so that when filled with a ballast that they will not be unintentionally moved by the propeller wash or jet blast of an aircraft. Some embodiments provide a bracket for securely attaching a barrier light to the bracket. This provides an added degree of safety for the airport environment.  
      The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.