Abstract:
An improved vault that facilitates the underground storage of electronic equipment, such as instrumentation for wireless telecommunications antenna systems. The vault preferably includes an flood evacuation system that prevents the electronic equipment from being submerged under water when the vault floods, a break-away lid to reduce or minimize injury, and a grated lid to prevent water from entering the main equipment chamber.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 60/483,332, filed Jun. 27, 2003, which application is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to subterranean enclosures for electronic equipment and, more particularly, to a subterranean vault for underground storage of electronic equipment, such as instrumentation for wireless telecommunications transceiver systems, and an evacuation system that protects the equipment against flooding. 
     BACKGROUND OF THE INVENTION 
     Public demand for wireless communications has grown at a tremendous rate. An increasing number of people rely on their wireless phones and other devices for an increasing number of uses including voice, messaging, data, video, and internet access. This enormous public demand has in turn fueled the need for additional carrier antenna sites to provide expanded wireless coverage to communities. 
     As the need for additional antenna sites has grown, so too has the installation restrictions set by many municipalities. Wireless carriers are being required to place their transceiver equipment in an aesthetically pleasing manner. In many municipalities the planning departments are unwilling to grant permit applications for unsightly tower installations. There is also a growing tendency for many of these municipalities to require even the smallest of transceiver circuitry units to be placed underground, and for the antennas to be disguised or stealthed. 
     The units housing the transceiver or transmitting and receiving circuitry for wireless communications systems come in different sizes, and have different power and transceiver configurations. The standard or “macro-cell” unit is a compact base transceiver station (“BTS”), which stores six (6) to eight (8) transceivers or radios requiring 1800 to 2200 watts of power. The smallest unit currently used, primarily where a mono-pole transceiver system is inappropriate, is a “micro-cell”, which typically houses one (1) to two (2) transceivers requiring 170 to 600 watts of power. To meet the restrictions imposed by the municipalities, these macro- and micro-cell units are placed in self contained, sealed subterranean vaults. These may be made of concrete or steel. 
     The problem with any self-contained, sealed underground vault is that the telecommunications equipment enclosed therein generates heat, which ultimately damages or destroys the equipment. Moisture, either from evaporation or flooding from rain, can also damage or destroy the equipment. These problems are typically solved by using an air conditioner and dehumidifier in conjunction with a water pump. However, in the case of flooding, if the pump is unable to keep up with incoming flow of water, the telecommunications equipment can become submerged in water and ultimately damaged or destroyed. 
     Thus, it would be desirable to provide the wireless communications industry with a vault to house telecommunications equipment underground that maintains proper climate control for equipment longevity and protects the equipment against flooding. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to an improved vault or cabinet for subterranean storage of electronic equipment, such as wireless telecommunications equipment. In a particularly innovative aspect of the invention, the cabinet includes a flood evacuation system that prevents the electronic equipment from becoming submerged as the cabinet floods with water. In a preferred embodiment, the flood evacuation system comprises a float-type member coupled to an equipment rack below the level of the electronic equipment. 
     In an alternative embodiment, the vault includes a break-away lid releasably coupled to the equipment rack to prevent or minimize injuries in the case of the lid being lowered onto someone&#39;s foot or hand. Preferably, the break-away lid is attached to the equipment rack with a spring loaded coupling. 
     In another alternative embodiment, the vault includes a grated lid or top to control heat management of the vault without having to use external or internal cooling systems. The grated lid allows air to flow into vault vent chambers and out of the main equipment chamber due to a chimney effect to keep electronic equipment housed in the vault at its ambient air temperature. Preferably, the grated lid includes a plurality of elongate vents or slots extending the width of the lid and having a diverter that diverts water into a gutter. The gutter then channels out of the lid. 
     Other aspects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an isometric view of a subterranean electronic equipment vault of the present invention. 
         FIG. 2  is a top view of the vault shown in  FIG. 1  with the lid gasket removed. 
         FIG. 3  is a partial isometric view of an equipment rack of the present invention. 
         FIG. 4  is a side view of the interior of the vault with the equipment rack in a lowered position. 
         FIG. 5  is a side view of the interior of the vault with the equipment rack in a partially raised position from a partially extended lift mechanism. 
         FIG. 6  is a side view of the interior of the vault with the equipment rack in a partially raised position from water rising in the equipment compartment. 
         FIG. 7  is a partial side view of the interior of the vault and cooling system. 
         FIG. 8  is a side view of the interior of the vault showing the and cooling system. 
         FIG. 9  is a plain view of closure device of the cooling system. 
         FIG. 10  is a side view of the interior of the vault with the equipment rack in a lowered position and having an alternative lid embodiment. 
         FIG. 11  is a detail view taken along line  11  in  FIG. 10  showing the coupling of a break-away lid spring coupled to the equipment frame. 
         FIG. 12  is a detail view taken along line  12  in  FIG. 10  showing the grated lid. 
         FIG. 13  is an isometric view of a single vent or slot of the grated lid shown in  FIG. 12 . 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Referring in detail to the figures, a cabinet or vault  10  for subterranean storage of electronic equipment is shown. As depicted in  FIG. 1 , the cabinet  10  includes an enclosure  11  that is preferably formed as a metal weldment. In a preferred embodiment, the enclosure  11  is a stainless steel weldment. Use of a metal, such as stainless steel, advantageously allows the surrounding earth to aid in the dissipation of heat from the vault  10  and, also, advantageously enables the vault  10  to be smaller, without sacrificing strength or equipment security. As a result, the vault  10  can advantageously be placed next to or under vertical structures, such as a light standard, in existing public rights of way. 
     Alternatively, the enclosure  11  may be formed of reinforced ultra violate inhibitent plastic injection molded material and may be made to any size necessary to accommodate the electronic equipment to be stored. 
     The enclosure  11  includes vertical side walls  12  coupled to a bottom plate or base  13 . As depicted in  FIGS. 4-6 , interior walls  14  and  15  divide the interior of the enclosure into a main or radio equipment compartment  16  and vent and other equipment compartments  17  and  18 . A top plate  20  ( FIG. 1 ) is coupled to the walls  12  and  14  at the top of the vault  10  and includes an equipment access opening  21  through which telecommunication and other electronic equipment can be loaded into the vault  10  or accessed for repair and maintenance. A lid  24  and rubber gasket  22 , which are discussed in greater detail below, seal the access opening  21 . 
     The equipment compartments  18  and vent air compartments  17  include releasably or hingedly coupled covers or lids  19  and  23 . The covers  19  and  23  may be opened to provide access to the vent and equipment compartments  17  and  18 . The vent compartment lids  23  preferably includes lowered air vents  26  covered with an air permeable mesh, preferably metal, to keep out debris and check valves  25  which are part of a water evacuation system discussed below. The lids  19  and  23  may include a handle (not shown), a releasably lockable hinge or shock absorber-type hinge (not shown) to maintain the lids  19  and  23  in a generally vertical position, a security locking system (not shown), and a magnetic seal similar to those used on refrigeration units (not shown). The equipment compartment lids  19  preferably provide locked access for lift control and equipment maintenance. 
     Referring to  FIGS. 2-6 , the cabinet  10  of the present invention preferably includes a rack  30  mounted inside the enclosure  11  to place telecommunications equipment in the enclosure  11  and to allow easy access by maintenance personnel when repairs are needed. The rack  30  includes four (4) generally vertically positioned posts  31  and bottom horizontally disposed frame member  33 , coupled to the posts  31 , and an equipment platform  32  coupled to the posts  31  and disposed above the bottom frame member  33 . A transceiver or radio cabinet  50  and equipment brackets  51 , comprising battery backup and charger  52  and control and load panels and main disconnect switch  53  and the like mounted thereto, are preferably mounted on the platform  32 . The lid  24  is preferably coupled to the posts  31 . The posts  31 , cross-members  33 , platform  32  and lid  24  are preferably sized such that the outer extremities of the rack  30  are positioned closely adjacent to the inner walls of the cabinet  10 . Four (4) guide rails or posts  35  are preferably positioned within the cabinet  10  adjacent the interior walls and the corner posts  31  of the rack  30  to guide the vertical ascent and descent of the rack into and out of the cabinet  10 . 
     As shown in  FIGS. 4 and 5 , the cabinet  10  preferably includes a scissor-like lift mechanism  40  to raise and lower the rack  30 . The lift mechanism is operably and releasably couplable to the bottom frame member  33  of the rack  30  and is preferably motorized, but may, in the alternative, be spring loaded. The spring force would be sufficient to cause a fully loaded unrestrained rack  30  to rise out of the enclosure  11  as shown in  FIG. 5 . The spring force is preferably 25 to 50 pound greater than a fully loaded rack  20 , thus requiring a maintenance worker to apply 25 to 50 pounds of offset downward force to position the rack  30  and electronic equipment in the enclosure  11 . If motorized, controls (not shown) would be provided to expand (see  FIG. 5 ) and contract (see  FIG. 4 ) the lift mechanism  40  to raise or lower the rack  30 . 
     In an alternative embodiment, a pulley and weight system, as described in U.S. patent application Ser. No. 09/614,496, which is incorporated herein by reference, may be substituted for the lift mechanism  40 . The weights are of sufficient weight such that a fully loaded unrestrained rack  30  is caused to rise out of the enclosure  11 . An offset force of 25 to 50 pounds is necessary to reposition the rack  30  in the enclosure  11 . 
     As shown in FIGS.  2  and  4 - 6 , rack stops  42  are provided within the enclosure  11  to position the rack  30  within the enclosure. Rack arms  44  are coupled to the bottom frame member  33  and are sized and positioned to abut the rack stops  42  to limit the upward and downward travel of the rack  30 . 
     Referring to  FIGS. 4-6 , the cabinet  10  includes a water evacuation system which is capable of venting any pooled water from the bottom of cabinet  10 . The evacuation system includes several float-type sump pump  60  located in the bottom of the cabinet  10 . A piping system (not shown) extends from the pumps  60  to exhaust valves  25  mounted to the vent compartment lids  17  shown in  FIGS. 1 and 2 . The exhaust valves  25  are commonly known one-way, pressure-type check valve. 
     Although the construction of the cabinet  10  advantageously allows the surrounding earth to aid in the dissipation of heat from the cabinet  10 , this cooling effect may be insufficient in certain climate conditions or as a result of equipment power consumption. A reduction in humidity or condensation within the cabinet may also be desirable for increased component life even when the temperature within the cabinet is being maintained at a desirable level, i.e., at or below about 100° Fahrenheit. To accommodate these potential cooling requirements, the cabinet  10 , as shown in  FIGS. 4-9 , includes a cooling system that preferably comprises separate cooling or vent compartments  17 , each sharing a common wall  14  with the radio or main equipment compartment  16 . 
     The cooling compartments  17  comprises a lid or top panel  18  and an opening or cooling vent  70  in the common wall  14 , preferably positioned toward the top of the common wall  14  to allow hot air and moisture to vent from the main compartment  16  to the cooling compartments  17 . The cooling compartment  17  has air vents  26  in the top panel  23 , exposed to surface air. The vents  26  are preferably louvered so that rain or water entering the cooling compartment  17  cannot fall through the opening  70  in the common wall  14 . 
     Should rain or other water enter the interior  71  of the cooling compartment  17  such that it rises to the level of the cooling vent  70 , a closure system  72 , as depicted in  FIGS. 7 and 8 , is provided to seal the cooling vent  70 . The closure system  72  preferably comprises a door  73  and a flotation device  74 . The door  73  is mounted in moveable relation with the common wall  14  and is adapted to seal the cooling vent  70  in the common wall  14 . As shown in  FIG. 9 , the door  73  is slidably mounted within a pair of opposing tracks or guides  76 . The tracks  76  are mounted on the common wall  14  and run vertically adjacent to the sides of the cooling vent  70  in the common wall  14 . The tracks  76  preferably extend from the top of the cooling vent opening  70  toward the bottom of the cooling compartment  17  beyond the bottom of the opening  70 . As shown in  FIGS. 7 and 8 , the door  73  slides or travels up from the bottom of the cooling compartment  17  to completely seal the opening  70  in the common wall  14  as the water level in the interior  71  of the compartment  17  rises. 
     The flotation device  74  comprises a floatable pad  77  attached to the door  73  on the inside  71  of the cooling compartment  17 . Preferably, the pad  77  is formed from Styrofoam, but may be formed from other suitable material or may comprise an inflatable bladder. The pad  77  is substantially the same height and width as the door  73  and approximately one-inch thick, and preferably has a buoyancy value sufficient to raise the door  73  as water fills the compartment  17 . To increase the surface area and, thus, the buoyancy of the pad  77 , a series of channels or cutouts  78  are formed in the pad  77 . If water floods the cooling compartment  17 , the door  73  simultaneous rises as the water level rises in the interior  71  of the cooling compartment  17 . With the aid of the water forcing the door  73  against the common wall  14 , the door  73  forms a water tight seal between the main compartment  16  and the cooling compartment  17 . However, in the absence of rain or flooding, the door  73  is open, allowing venting of heat and moisture from the cabinet  10 . 
     In an alternative embodiment, the closure mechanism  70  may include a float and pulley system (not shown) adapted to raise the door  73  as the water level in the cooling compartment  17  rises. Also, a gasket or the like may be positioned between the door  73  and the common wall  14  to further facilitate a water tight seal between the main compartment  16  and the cooling compartment  17 . 
     Unlike conventional designs, the vault or cabinet  10  of the present invention can be placed in virtually any city, near any existing vertical structure, e.g., a light standard, which is mounted on or near a sidewalk, while being fully disguised, and tending to pose no hazards to pedestrians, who might otherwise trip on an exposed unit. 
     The cabinet  10  of the present invention also advantageously includes an equipment flood evacuation system to prevent the expensive and sensitive telecommunication and other electronic equipment housed in the main equipment compartment  16  from becoming submerged and, thus likely destroyed, if the main compartment  16  of the cabinet  10  were to flood with water. The evacuation system preferably includes a flotation device  80  coupled to the rack  30  to raise the rack  30  as the water level within the main compartment  16  rises. Preferably, the evacuation system is configured to lift the telecommunication and other electronic equipment ( 50 - 53 ) clear out of the main compartment  16  while leaving a portion of the rack  30  within the compartment. 
     As depicted in  FIGS. 4-6 , the rack flotation device preferably comprises a floatable pad or block  80  disposed between the equipment platform  32  and the bottom frame member  33  of the rack  30 . Preferably, the block  80  is formed from Styrofoam, but may be formed from other suitable material or may comprise an inflatable bladder. The block  80  preferably has a buoyancy value sufficient to raise a fully loaded rack  30  as water fills the compartment  16 . To increase the surface area and, thus, the buoyancy of the block  80 , a series of channels or cutouts (not shown) similar to those discussed in regard to the pad  77  above may be formed in the block. 
     In operation, if water floods the main compartment  16 , the rack  30  simultaneous rises as the water level rises in the interior of the main compartment  16 . With the lid  24  of the cabinet  10  fixed to the rack  30 , the rack  30  can freely rise out of the cabinet  10  without human intervention with aid of the water forcing the rack  30  upward. As with the lift mechanism  40 , the ascent of the rack  30  is guided by the guide rails  35  and limited by the rack stops and arms  42  and  44 . However, in the absence of flooding, the rack  30  remains within the main compartment  16  with the lid  24  pressing against the gasket  22  to form a water tight seal between the exterior of the cabinet  10  and the main compartment  16 . In order to insure a water tight seal, the gasket  22  is preferably about three to six (3 to 6) inches wide. 
     In an alternative embodiment, the evacuation system may include a float and pulley system (not shown) adapted to raise the rack as the water level in the main compartment  16  rises. 
     Turning to  FIGS. 10 and 11 , an alternative embodiment of the vault  100  is depicted. As shown in  FIG. 11 , a break-away lid  224  is releasably coupled to the equipment rack  30  allowing the lid  224  to give in the case of contact with something such as someone&#39;s foot or hand. Preferably, the break-away lid  224  is attached to the equipment rack  30  with a spring loaded coupling comprising a bolt or other fastener  230  coupled to the lid  224  and a spring  232  coupled to the bolt  230  and rack post  31 . One skilled in the art would recognize that the bolt  230  could be coupled to the post  31  and the spring could be coupled to the bolt  230  and the lid  224 . As depicted in  FIG. 11 , the bolt  230  and spring  232  assembly are preferably recessed within the post  31 . 
     The springs  232  are preferably sized to counter weigh the weight of the lid  224 . For instance, if the lid  232  weighed 200 lbs., the springs  232  would exert a 200 lbs. counter force against the lid  224 . 
     As depicted in FIGS.  10  and  12 - 13 , another alternative embodiment of the vault  100  includes a grated lid or top  224  to control heat management of the vault  100  without having to use external or internal cooling systems. The grated lid  224  prevents rain or other water from failing directly into the main chamber  16  and allows air to flow into vault vent chambers  17  and out of the main equipment chamber  16  due to a chimney effect to maintain electronic equipment housed in the vault  100  at its ambient air temperature. To increase the chimney effect, it may be preferable to lower the location of the cooling vents  70  in the common walls  14 . 
     Preferably, the grated lid  224  includes a plurality of elongate vents or slots  240  extending the width of the lid  224 . Each slot is defined by a pair of vertical walls  244  and  246  and includes a diverter or sloping wall  245  extending off of the first wall  244  and sloping towards the second wall. The diverter  245  diverts water into a gutter or channel  242  extending off of the second wall. The gutter is preferably sloped towards one side of the lid  224  and channels the water toward a sloped faced vault skirt  225  and out or off of the lid  224 . The gutter  242  includes a generally horizontal bottom wall  241  and an upwardly sloping side or retaining wall  243  directed toward the first wall  244  of the vent  240 . Alternatively, the gutter  242  may comprise a single curved wall. A slotted plate or connective member  248  is coupled to all of the vertical walls  244  and  246  to form the grated lid  224 . 
     As shown in  FIG. 10 , the vault  100  preferably includes a skirt  225  located substantially at grade level. The skirt  225  preferably includes a sloped face  227  to ease transition from grade level to a slightly elevated lid  224 . In the grated lid embodiment, the sloped face  227  and internal wall  223  are preferably perforated to allow water channeled from the gutter  242  of the grated lid  224  to flow off or out of the lid  224 . 
     While the invention is susceptible to various modifications and alternative forms, a specific example thereof has been shown in the drawings and is herein described in detail. It should be understood, however, that the invention is not to be limited to the particular form disclosed, but to the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the appended claims.