Abstract:
An automatic barricade includes a trench across a road that is covered by a grate allowing vehicular traffic during normal dry weather. Inside the trench is a series of barricade elements, each of which includes a float. When rising water fills the trench to a predetermined level, each float rises and elevates the elements above the road. The barricade elements are sufficiently robust and intimidating to deter motorists from driving over them but are spaced apart to be light enough to be easily actuated by the float. The barricade elements are sufficiently close together that vehicles cannot pass between them. In another embodiment, a sensor is adjacent the trench to detect rising water and communicates with a motor connected to the barricade elements for raising them to a traffic blocking position.

Description:
RELATED APPLICATIONS 
   This application is based on provisional application Ser. No. 60/444,412, filed Feb. 3, 2003, entitled AUTOMATIC BARRICADES FOR LOW WATER CROSSINGS, and is a continuation-in-part of application Ser. No. 10/769,454, filed Jan. 30, 2004, now abandoned originally entitled AUTOMATIC BARRICADES FOR LOW WATER CROSSINGS. 
   This invention relates to a barricade across a road at a location adjacent a low water crossing to deter motorists from driving through rising flood water, and more particularly to a barricade that is automatically elevated by rising water. 

   BACKGROUND OF THE INVENTION 
   It is well known that vehicle drivers frequently underestimate the force of water flowing across a low water crossing. During floods, news reports are replete with situations where otherwise rational people drive across a low water crossing only to be stranded in the road or swept downstream by flowing water. Sometimes these situations end in disaster, sometimes rescue personnel risk their safety and lives to rescue the drivers and occupants of vehicles. 
   Governmental authorities in flood prone areas have typically responded to this situation by sending police or firemen to place standard traffic barricades in the road adjacent low water crossings. These barricades must be placed in a timely manner at appropriate locations, must be sufficient in size and placement to deter motorists and must be monitored to prevent the barricades from being moved or removed by motorists or flood water. 
   The failures of current techniques are in categories that match up with the requirements of effective barricades, i.e. they are not placed in a timely manner, they are not placed at appropriate low water crossings or are inappropriately positioned at proper low water crossings, motorists drive around or move barricades and flood waters turn barricades over or sweep them downstream. There is accordingly no dispute that current techniques are inadequate, the most persuasive evidence being motorists stranded in the road or swept downstream during floods. 
   There are many types of indicators or alarms that have been proposed or used to show attentive motorists that water has risen and by how much. The simplest and most widely used is a piece of pipe embedded in the ground near a low water crossing with marks on the pipe showing the height of water flowing over the road. A number of proposals have been made for alarms or indicators placed on the side of the road, which are actuated by rising water, to indicate that the water height is dangerous such as shown in U.S. Pat. Nos. 2,607,835 and 4,879,545. Other disclosures of interest are found in U.S. Pat. Nos. 4,377,352; 5,460,462; 5,862,775 and 6,623,209. 
   SUMMARY OF THE INVENTION 
   In this invention, an automatic barricade is placed across a road adjacent a low water crossing. The barricade is placed in a trench dug across the road at an elevation where the water level is sufficient to activate the barricade and raise it to a position blocking traffic from proceeding along the road. Thus, rising water fills the trench sufficient to raise the barricade and empties when water levels decline so the barricade lies down in the trench. The trench is covered by a grate which allows traffic to drive across the trench in normal dry conditions. If experience dictates that water rises a substantial distance during floods at a particular low water crossing, additional automatic barricades are preferably placed at different elevations spaced in the direction of travel. 
   The barricade is preferably actuated by a series of floats operably connected to each of a series of spaced apart barricade elements. The barricade elements are sufficiently intimidating to deter a motorist from driving over them, are spaced close enough together that a motorist cannot drive between them and are sufficiently light to be easily raised by rising water acting on the float. 
   In another embodiment, a sensor in or adjacent the trench detects rising water and delivers an output signal that operates a mechanism to raise the barricade elements. 
   It is an object of this invention to provide an automatic barricade placed across a road adjacent a low water crossing. 
   A further object of this invention is to provide an automatic barricade which is sufficient to deter motorists from attempting to cross a low water crossing in times of flood. 
   Another object of this invention is to provide an automatic barricade that does not require human intervention in the activation of the barricade and which does not require monitoring during times of flood. 
   A more specific object of this invention is to provide an automatic barricade placed across a road that is raised and lowered by a float inside a trench which houses the barricade. 
   Another more specific object of this invention is to provide an automatic barricade placed across a road that is raised and lowered in response to a sensor detecting rising water adjacent the barricade. 
   These and other objects and advantages of this invention will become more apparent as this description proceeds, reference being made to the accompanying drawings and appended claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a pictorial view of a low water crossing showing a series of barricades extending in the direction of travel; 
       FIG. 2  is a top view of part of the trench and grate; 
       FIG. 3  is a cross-sectional view of  FIG. 2 , taken substantially along line  3 — 3  thereof, as viewed in the direction indicated by the arrows, showing only one barricade element in an upright position; 
       FIG. 4  is a cross-sectional view of the  FIG. 2 , taken along line  4 — 4  thereof, as viewed in the direction indicate by the arrows, showing the barricade element in the stowed position; 
       FIG. 5  is a view of the open end of the trench of the barricade of this invention; 
       FIG. 6  is a broken isometric view of a more sophisticated float operated latch; and 
       FIG. 7  is a broken isometric view showing another embodiment of this invention; and 
       FIG. 8  is a plan view of the embodiment of  FIG. 7 . 
   

   DETAILED DESCRIPTION 
   Referring to  FIGS. 1–5 , there is illustrated a barricade  10  which is placed across a road  12  adjacent a low water crossing  14  created by a dry creek or drainage path  16  intersecting the road  12 . The barricade  10  acts in response to rising flood water to raise a series of barricade elements  18  to deter motorists from driving in a direction of travel  20  along the road  10 . The barricade elements  18  are preferably made of a resilient material or of an injection molded polymer to prevent damage to vehicles striking the elements  18 . 
   As used herein, the word road is intended to be sufficiently broad to include (1) the traffic surface  22 , (2) the traffic surface  22  and a shoulder  24  and/or (3) the traffic surface  22 , the shoulder  24  and all or part of the right-of-way  26 . As a practical matter, the barricades  10  of this invention will generally extend only across all or part of the traffic surface  22  and perhaps all or part of the shoulder  24 , depending on local conditions such as whether the shoulder  24  is paved, the slope of the shoulder  24  and the like. The traffic surface  22  may, of course, be asphalt, concrete, gravel, caliche or other suitable road materials. The direction of water movement  28  is transverse to the travel direction  20  and typically is perpendicular to the travel direction  20 . 
   The barricade  10  includes a trench  30  extending across the road  12 . To minimize flood borne debris from entering, the trench  30  includes a closed end  32  on the upstream side of the road  12  and an open end  34  on the downstream side of the road  12 . Rising water accordingly enters the trench  30  from the downstream side of the road  12  so most flood borne debris goes past the entrance to the open end  34  of the trench. The trench  30  is lined with concrete  36  to provide an open top receptacle  38  for receiving the movable components of the barricade  10 . 
   The top of the trench  30  is spanned by a cover or grate  40  allowing vehicle traffic over the trench  30  in normal weather. The grate  40  is of lattice work construction allowing water flow into the trench  30  and also provides a series of long slots  42 ,  44  allowing the barricade elements  18  to move from a stowed position in the receptacle  38  below the traffic surface  22  to an upright position blocking the road  12 . The slots  42 ,  44  are staggered or offset in the direction of travel  20  so the barricade elements  18  may be spaced closely enough to prevent a vehicle from travelling between them and may be sufficiently long to extend substantially out of the water even though it may be several feet deep. Although the barricade elements may be of any suitable length, a typical barricade element  18  in the elevated position extends 3–5′ above the traffic surface  22 . 
   The barricade elements  18  are sufficiently strong and intimidating in an upright position that no reasonable motorist will be tempted to drive over them. The barricade elements  18  are sufficiently light to be raised by any suitable mechanism which is simple, inexpensive, relatively maintenance free and durable. The barricade elements  18  are spaced apart transverse to the direction of travel  20  so they may be light but are close enough together to prevent vehicle travel between them. Although the barricade elements  18  are preferably mounted for independent movement, they may be tethered together to provide an additional visual or physical obstruction. It will be seen that the barricade elements  18  do not deter movement of water between them so the barricade  10  is permeable to water. 
   To these ends, the barricade elements  18  are each pivotally mounted in the receptacle  38  by a suitable bracket  46  and pivot pin  48 . The barricade element  18  includes a rod or elongate element  50  on which is mounted a float  52  of suitable size and buoyancy. The bracket  46  is slightly askew and a suitable stop  53  is positioned so the element  18  is tilted slightly so, when the float  52  subsides, the element  18  always falls in the correct direction. The upper end  54  of the barricade element  18  is preferably enlarged and provides suitable reflective markings  56  visible from a great distance. It will be seen that the float  52  may be connected to the barricade element  18  or may slide on the rod  50 . In any event, when water rises in the trench  30 , the float  52  rises in the receptacle  38  pivoting the element  18  to an upright position. When flood water recedes, water drains from the trench  30 , causing the float  52  to subside and the element  18  to lie back into the trench  30 . 
   If the low water crossing  14  is a situation where water rises substantially, one or more additional barricades  10  may be installed across the road  12  at increasing elevations away from the crossing  14 , all as shown in  FIG. 1 . The vertical distance between successive barricades  10  is selected to be less than the height of the barricade elements  18  above the traffic surface  22 . For example, if the barricade elements  18  extend four feet above the traffic surface  22 , the adjacent barricades  10  will typically be installed at elevation differences of two feet so that at least two feet of the barricade elements  18  will extend above the water in any situation. 
   Referring to  FIG. 2 , there is illustrated another feature of this invention. The upper elements  18  rotate about axes  60  while the lower elements  18  rotate about axes  62 . Thus, from the motorists viewpoint, the spacing between the upright barricade elements  18  is the distance from one of the axes  62  to the nearest axis  60 . An important feature of this invention is that the barricade elements  18  rotate, during movement from the stowed position in the trench  30  toward the upright position, in the same direction as the water flow direction  28 . The reason is that water flow will tend to keep the elements  18  upright. If the barricade elements  18  were pivoted in the opposite direction, water flow would tend to push them down and water flow of sufficient velocity would submerge them, thereby rendering the barricade elements  18  ineffective. 
   Referring to  FIG. 5  there is illustrated another feature of this invention. The illustration in  FIG. 5  assumes the trench  30  extends to the edge of the traffic surface  22  or to the edge of a paved shoulder  24 . The outside edge of the open end  34  of the trench  30  is accordingly inclined to match the slope on the edge of the road. In the event there is a potential for traffic outside the grate  40 , a suitable supplemental grate  66  may be provided as shown in  FIG. 5  where an alternative construction of the trench  30  is shown to be lined with pre-cast concrete elements providing a structural box. 
   Installation and use of the automatic barricade  10  of this invention should now be apparent. The desired depth of the trench  30  is established by design, based on the desired depth of water over the road sufficient to raise the barricade elements  18 . Using suitable surveying instruments, the depth of the trench  30  on the ground is located. A concrete saw (not shown) or other suitable device is used to cut the traffic surface  22  and a back hoe or other equipment is used to evacuate a ditch to receive the concrete lining  36  of the trench  30 . The concrete lining  36  may be poured on site or may comprise a pre-cast unit placed in the ditch. The brackets  46  are positioned in the trench  30  and the barricade elements  18  and floats  54  are installed. 
   There is always a problem maintaining outdoor equipment analogous to this invention. This invention, however, is relatively simple to maintain. Once or twice a year, a water truck drives to the low water crossing equipped with this invention and discharges into the trench  30  a volume of water ten-fifty times the volume of the trench. The water will run out of the open trench end  34  carrying with it any debris in the trench. This and an inspection of the working components of the invention and repair of any broken components will suffice. 
   The barricade elements  18  of any particular installation are designed to be upright at a predetermined water depth over the road  12 . With a simple pivoted barricade element  18  and float  52 , the barricade element  18  tends to rise up through the grate  40  before the full water depth is reached. In many installations, this is not material because when flood waters rise, they rise so fast that the interval between the time the barricade element  18  starts to rise and when it is fully upright is very short, e.g. a few minutes. In other installations where water rise is not historically so fast, it may be desirable to keep the barricade elements  18  below the grate  40  until the water over the road  12  reaches the predetermined design depth. In this event, a float operated latch  68  of any suitable type having a retractable element  70  may be provided to prevent movement of the barricade element  18  past the grate  40  until the water over the road  12  has reached its predetermined design depth. 
   Referring to  FIG. 6 , there is illustrated a more sophisticated float operated latch  70  incorporated into a bracket  72  pivotally mounting a rod or barricade element  74  for rotation about an axis  76 . To this end, the bracket  72  comprises a pair of L-shaped members  78 ,  80  secured to the concrete lining  82  of a trench  84  by suitable fasteners (not shown). A pivot pin  86  mounts the barricade rod  74  for rotation and a stop  88  between the bracket members  78 ,  80  prevents overrotation of the barricade rod  74 . As so far described, the barricade element  74  operates in the same manner as the barricade element  18 . 
   The float operated latch  70  includes a float  90  located below the top of the trench  84 , a rod  92  fixed to a crank arm or offset section  94  and a stop  96  fixed to the crank arm  94 . The crank arm  94  is mounted on the bracket  80  by a pin  98  for rotation about an axis  100 . The stop  96  extends through an arcuate slot  102  to underlie the end  104  of the barricade rod  74  in the normal towed position of the barricade rod  74 . A pair of stops  106 ,  108  on the bracket member  80  control the limits of rotation of the float rod  92 . When no flood water is in the trench  84 , the barricade rod  74  is more-or-less horizontal and the float rod  92  abuts the stop  106  as shown in  FIG. 6 . When flood water rises in the trench  84 , a float (not shown) on the barricade rod  74  provides a force tending to rotate the rod  74  in a counterclockwise direction so the rod end  104  abuts the stop  96  thereby preventing upward movement of the barricade rod  74  until the float  90  moves. When flood water rises in the trench  84 , the float  90  pivots toward the stop  108 . When the float  90  rotates a sufficient distance, the stop  96  moves through the arcuate slot  102  a sufficient distance to move off the rod end  104  thereby allowing the barricade rod  74  to rotate upwardly in a counterclockwise direction to raise the barricade element abruptly, rather than gradually as would occur without the float operated latch  70 . 
     FIG. 6  also shows another important feature of this invention. During receding of flood waters, it is desired that the barricade elements remain upright until water level subsides to a safe predetermined level and then abruptly fall back through the slots in the grate  109  into the trench  84 . It is accordingly desirable to provide a float operated latch  110  holding the barricade rod  74  in an upright traffic blocking position until flood waters recede to a safe level at which time the barricade elements  74  abruptly move to their stowed position inside the trench  84 . To this end, the latch  110  includes a pair of somewhat inclined slots  112 ,  114  aligned in the bracket members  78 ,  80 . A stop  116  extends through the slots  112 ,  114  and is made buoyant in any suitable manner. The simplest construction of the stop  116  is a hollow buoyant cylinder provided with a suitable keeper (not shown) so it freely rises and falls in the slots  112 ,  114  in response to rising and falling water levels in the trench  84  but does not move axially out of the slots  112 ,  114 . 
   When the barricade element  74  is buoyed to its upright traffic blocking position, the stop  116  has risen to the top of the slots  112 ,  114 . When water starts to recede, the barricade rod  74  rotates clockwise and moves away from its stop  88  against the buoyant stop  116 . As flood water continues to recede, the rod  74  applies an increasing force to the buoyant stop  116 . Ultimately, the stop  116  falls in the slots  112 ,  114  due to the applied weight of the rod  74 , due to movement of the stop  116  caused by the subsiding water level acting on the stop  116  or a combination of both. This allows the barricade rod  74  to abruptly rotate in a clockwise direction to its stowed position inside the trench  84 . 
   If the trenches  30  were located at the lowest spot in the road  12 , the floats  52 ,  90 ,  116  would act too early and the barricade elements  18 ,  74  would rise when the water level reached the lowest spot in the road. Thus, the trenches  30 ,  84  are located above the lowest spot in the road  12  by a distance sufficient to raise the barricade elements  18 ,  74  at a time when water rises a dangerous distance above the lowest spot in the road  12 . 
   Referring to  FIGS. 7 and 8 , there is illustrated another embodiment  120  of this invention comprising a concrete lined trench  122  extending across the road  124  at or adjacent the low water crossing  126 . A grate  128  covers the trench  122  and provides slots transverse to the direction of vehicle travel for allowing a barricade element  130  to move between a generally horizontal stowed position in the trench  122  and an upright position blocking traffic along the road. The barricade element  130  is conveniently pivoted by a pin  132 . 
   A sensor  134  is located to sense rising water in the crossing  126  and is equipped with a suitable communication link (not shown), such as a wire, radio link or the like, to energize a mechanism  136  to raise the barricade element  130  in response to rising water. Preferably, the sensor  134  is located in the trench  122  or in such close proximity to the trench  122  that the barricade elements  130  are not raised until dangerous conditions are more-or-less imminent. As used herein, the term adjacent the trench means inside or in close proximity to the trench. 
   The mechanism  136  may be of any suitable type, such as an electric hydraulic motor driven by a suitable power source, such as a connection to the power grid, a solar panel or the like. The mechanism  136  is connected in any suitable manner to the barricade element  130 , such as by a drive connection  138  connected to a link  140  rigid with the barricade element  130 . It will accordingly be seen that energizing the motor  136  rotates the barricade element  130  for an arc sufficient to raise the barricade element  130  upwardly out of the trench  122  into a traffic blocking position. 
   It will be apparent that the principles of this invention are equally applicable to other road structures, such as bridges, which are occasionally inundated by flood water, although the details of construction may have to be modified to take into account the construction of bridges or other road structures. 
   Although this invention has been disclosed and described in its preferred forms with a certain degree of particularity, it is understood that the present disclosure of the preferred forms is only by way of example and that numerous changes in the details of operation and in the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.