Patent Document

BACKGROUND OF THE INVENTION 
   Cabinets adapted to house components of a distributed antenna system, such as fiber optic repeater and associated power source components, are commonly configured as unprotected, anchored structures. It is necessary, therefore, for such cabinets to adequately protect the components housed in the cabinets from damage, particularly damage which is intentionally inflicted, and yet readily permit service or replacement of the components when necessary. At the same time, such cabinets must be provided with adequate ventilation, particularly for fiber optic repeater components, by permitting adequate cooling air admission and heated air exhaust. This invention, accordingly, addresses three specific problems or needs related to deployment of fiber optic repeater distributed antenna systems. Specifically, the invention addresses the need to protect fiber optic repeater components from vandalism, the need to enclose power components directly below the repeaters, and the need for uninhibited ventilation, particularly of cabinet portions adapted to house fiber optic repeaters. 
   SUMMARY OF THE INVENTION 
   In accordance with one preferred embodiment of the invention, a cabinet is adapted to enclose a fiber optic repeater and power source components for the repeater. The cabinet includes a first cabinet portion partially enclosing a first chamber in which the repeater is receivable, a second cabinet portion at least partially enclosing a second chamber in which the power source components are receivable, and a door mounted to the first cabinet portion so as to be movable between a closed position, in which access to the first chamber is prevented, and an open position, providing access to the first chamber. A locking mechanism by which the door can be securely retained in the closed position includes a handle which is redundantly securable in an inoperative position, thereby preventing locking mechanism operation and precluding access to the first chamber through an opening to the first chamber which is covered by the door. In the particular embodiment described, the first chamber is an upper chamber and the second chamber is a lower chamber, but this is not necessarily so. 
   The handle is preferably redundantly securable in the inoperative position by a pair of locks. A post, preferably secured to the door and extending through an opening in the handle when the handle is in its inoperative position, advantageously includes a hole through which a shackle of a padlock forming one of the locks can extend. The shackle and the post are sized so that the shackle closely matches an outer contour of the post so as to preclude placement of a cutting device between the shackle and the outer contour. The other lock is preferably disposed at an end of the handle, adapted to retain the handle in its inoperative position, and operable by way of a particular tool, such as a wrench. 
   The first and second cabinet chambers are ventilated, with the first chamber including at least one manifold adapted to direct air entering into said first chamber to a cooling air intake of the repeater and/or to direct heated air exiting the repeater out of the first chamber. The first chamber includes a shelf which is adapted to accommodate any of several types of fiber optic repeaters and which is slidable between a first position, in which the repeater may be in use, and a second position, in which the repeater may be serviced or replaced. 
   The first and second chambers are separated by a divider having openings therein adapted to permit interconnection of the repeater and the power source components. In the preferred embodiment of the invention, three connections are enabled: (1) a fiber connection from the ground to the repeater in the upper chamber, (2) a coaxial cable connection from the repeater back out to the antenna mounted on a pole, and (3) a power cable connection from the ground to the power source in the lower chamber and then from the power source to the repeater in the upper chamber. 
   An enclosure according to the invention thus defines two compartments. One of these compartments is for a repeater, while the other is for power components. A door providing access to the repeater compartment has a dual locking system to prevent vandalism, and the repeater compartment contains a sliding shelf or drawer to hold the repeater equipment. The sliding shelf has interchangeable mountings so as to accommodate both ADC and Mikom/Andrew repeaters, and includes openings for electrical, coaxial, and fiber optic connections. 
   The cabinet enclosure is designed to provide optimal ventilation. To this end, the bottom front panel enclosing the power equipment compartment is ventilated, the top front panel has a ventilation manifold opening located so as to provide air flow directly to an intake duct on the front of a repeater, and the top hood of the enclosure is also ventilated. 
   The cabinet, optimally configured, is a ventilated aluminum box having the sliding drawer assembly and the locking, vandal-proof front access door, with the lower, inside panel/door made of steel. Materials other than aluminum, such as steel or plastic, could be used to produce the cabinet. Again, the sliding drawer assembly that holds the fiber optic repeater may be configured with interchangeable mounts to accommodate two (or more) types of repeaters, and ventilation is optimized by having the lower front panel, the upper front panel, and the top hood ventilated. The aluminum is finished with a baked-on powder coating paint which is applied post-manufacture and which serves to make it easier to remove any sort of painted-on graffiti. 
   In terms of preventing vandalism, the enclosure actually has a two level system. To open the main access door to the fiber optic repeater (i.e., the door providing access to the upper compartment), a heavy gauge padlock must be opened. The padlock is small and positioned so that it is impossible to place a bolt cutter between the door lock assembly and the shackle of the padlock. Once the padlock is open, a particular tool, such as a 7/16″ can wrench, is required to get the door open. The fact that a can wrench is not usually carried by members of the public, combined with the fact that the unique padlock system is not susceptible to vandalism by bolt cutters, make the enclosure highly secure. 
   Other features of the invention will become apparent from the following description when considered in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a front view of a cabinet according to the present invention; 
       FIG. 2  is a rear view of the cabinet shown in  FIG. 1 ; 
       FIG. 3  is a view of the interior side of a door which closes an opening to an upper chamber of the cabinet; 
       FIG. 4  is a view of the upper chamber of the cabinet showing a sliding shelf within the upper chamber in a pushed-in position; 
       FIG. 5  is a view of the cabinet with its front lower panel removed and showing a lower cabinet chamber; 
       FIG. 6  is a view of a top wall of the upper chamber shown in  FIG. 4 ; 
       FIG. 7  is a view of the upper chamber which is similar to the view of  FIG. 4  but in which the sliding shelf is illustrated in a pulled-out position; 
       FIG. 8  is a view showing openings in a divider wall located between the upper and lower chambers of the cabinet; 
       FIG. 9  is a view of a handle forming part of the locking mechanism in an inoperative or closed position; and 
       FIG. 10  is a view of the handle in an operative or open position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   A door  10  and a cabinet front lower panel  12  are best seen in the view of the cabinet illustrated in  FIG. 1 , while cabinet rear upper and lower panels  14  and  16  are best seen in the illustration provided by  FIG. 2 . The door  10  and the panels  12 ,  14 , and  16  are all provided with slots  18  which permit air circulation in a manner which will be described. The door and the panel material is deformed immediately above each of the slots so as to define overhanging, rain-deflecting protrusions  20 . 
   The cabinet rear upper panel  14  forms part of an upper cabinet frame portion, which is generally designated  22  as shown in  FIG. 4 , while the cabinet rear lower panel  16  forms part of a lower cabinet frame portion, which is generally designated  24  as shown in  FIG. 5 . The upper and lower cabinet frame portions may be unitary but, as illustrated, are separately constructed and then joined together. A hinge  26  is secured by connectors  23  such as bolts or other fasteners, rivets, or welds, as appropriate, to both the door  10  and the upper cabinet frame portion and interconnects the door and the upper cabinet frame portion so that the door  10  can swing between the closed position shown in  FIG. 1  and the open position shown in  FIGS. 3 and 4 . 
   A lower divider wall  28  defines a base or bottom of an upper chamber  30 , adapted to receive the repeater, and separates the upper chamber  30  from a lower chamber  32 , adapted to receive the power components for the repeater. The divider wall  28  thus constitutes a floor of the upper cabinet frame portion  22 , and, as is apparent from  FIG. 3 , may operate to secure that upper cabinet frame portion  22  to the lower cabinet frame portion  24  through the use of connectors  23 . 
   The upper cabinet frame portion  22  includes the divider wall  28 , a pair of side walls  34  extending upwardly from the divider  28 , and a top wall  31  (see  FIG. 6 ) interconnecting the side walls  34  at the upper ends of the side walls. The cabinet rear upper panel  14 , the lower divider wall  28 , the top wall  31 , and the side walls  34  may be of a one-piece, unitary construction and together form the upper cabinet frame portion  22 . 
   The front surface  36  of the top wall  31  is visible in  FIG. 4 . A flange  29  (see  FIG. 8 ), defined at forwardly facing edges of the divider wall  28 , the side walls  34 , and the front surface  36 , delimits a forward opening into the upper chamber  30 , and is provided with resilient sealing material  38 . The material  38  provided on the flange delimiting the upper chamber opening cooperates with another flange  40  defined around the perimeter of the door  10  in order to provide adequate sealing against water intrusion when the door  10  is closed. 
   The lower cabinet frame portion  24  includes the cabinet rear lower panel  16  and a pair of side walls  42  with flanges  44  defined at least partially around the perimeter thereof. The cabinet rear lower panel  16  and the side walls  42  with the flanges  44  may be of a one-piece, unitary construction and together form the lower cabinet frame portion  24 . A front upper lateral member  46  and a front lower lateral member  48  are adapted to be fastened by connectors  23  to the flanges  44 . The flanges  44  at the forward facing portion of the frame portion  24  and the front lateral members  46  and  48  delimit a forward opening into the lower chamber  32 . 
   As is best shown in  FIG. 5 , a flange or flanges  50  depending from the lower edge of the cabinet front lower panel  12  can be received in a hole or holes  51  in the front lower lateral member  48 , and at least one rotatable locking element  52  cooperates with the front upper lateral member  46 , thereby securing the cabinet front lower panel  12  in place on the lower cabinet frame portion  24 . As illustrated, two rotatable locking elements  52 , which are star locks, are provided. The use of a can wrench such as that which will be described may be required to rotate each locking element  52 . Alternatively, the use of a key or other such element could be required. 
   A top cover  54  is secured by connectors  23  to the top of the upper cabinet frame portion  22  and encloses the top wall  31  of the upper cabinet frame portion  22 . The top wall  31  includes an opening therein, which opening is visible in  FIG. 6 . A ventilation grid  33  is secured to the inner surface of or, alternatively, formed in, the top wall  31  as shown in  FIG. 6 . Air is thus permitted to flow out of the upper chamber  30  through the ventilation grid  33  and then through spaces (not shown) defined between rear and front overhanging portions  57  and  59  of the top cover  54  and the upper surface of the top wall  31 . 
   As best seen in  FIGS. 3 ,  4 , and  5 , screen filters  56  are secured, by adhesive  58 , to the inner surfaces of the door  10  and the panels  12 ,  14 , and  16  so as to prevent insects from entering into the chambers  30  and  32  through the slots  18 . A screen filter may optionally be secured over the ventilation grid  33  for the same reason, as shown in  FIG. 6 . 
   The door  10  is provided with a supply manifold  60  riveted or otherwise attached to the interior thereof. The supply manifold  60  has an opening  61  which is adapted to line up with a cooling air intake of a fiber optic repeater, which is to be located in the upper chamber  30 , so as to direct air entering into the chamber  30  through the slots  18  in the door  10  to that cooling air intake. The cabinet rear upper panel  14 , similarly, is provided with an exhaust manifold  62  riveted or otherwise attached to the interior thereof. Heated air exiting the repeater will enter an opening  64  of the exhaust manifold  62  and is then directed out of the cabinet. A deflector  66 , best shown in  FIG. 7 , facilitates entry of the heated air exiting the repeater into the exhaust manifold opening  64 . 
   A substantially U-shaped bracket  70  is secured by connectors  23  to each of the side walls  34  forming part of the upper cabinet frame portion  22 . The brackets  70  oppose and are parallel to each other. Each bracket  70  has a track  72  provided on its side facing the other bracket  70 . Each track  72  is adapted to receive a corresponding guide  74  provided on opposite lateral sides  78  of a sliding shelf  76 . The tracks  72  and the guides  74  cooperate to permit the shelf to slide between a pushed-in position, illustrated in  FIGS. 4–5  and  8 , and a pulled-out position, illustrated in  FIG. 7 . The fiber optic repeater, in use, is disposed on the shelf  76 . By way of the tracks  72  and the guides  74 , the shelf is readily displaced between its pushed-in position, in which the repeater may be in use, and its pulled-out position, in which the repeater may be serviced or replaced. 
   The shelf  76  has openings  80  defined therein which are adapted to accommodate any of several types of fiber optic repeater equipment, such as the Mikom/Andrew and ADC fiber optic repeaters mentioned. The openings  80  provide for mounting of either type of repeater, should it be necessary or desirable to replace one repeater type with another. It is alternatively possible, of course, to replace one shelf  76  having openings specific to one type of repeater with another shelf  76  having openings specific to another type of repeater. 
   As illustrated in  FIGS. 3 ,  4 ,  7 , and  8 , the divider wall  28  is provided with access holes  82  for the necessary electrical, coaxial, and fiber optic cable connections. Bearing rings  84 , in the form of rubber grommets, are incorporated in the access holes to prevent cable damage. 
   A crank  86 , best shown in  FIG. 3 , is mounted on and affixed to a crankshaft  88  extending through the door  10  by way of an appropriate bearing element  90 . Rods  92  are pivotally secured to opposite ends of the crank  86 , and pass through guides  94  affixed to the interior of the door  10 . Rotation of the crankshaft  88  in a clockwise direction as seen in  FIG. 3  causes rotation of the crank  86  which, in turn, causes ends  96  of the rods  92  to retract or move toward one another, while rotation of the crankshaft  88  in a counterclockwise direction causes the ends  96  to extend or move away from one another. Ends  96  may be configured as rollers. By appropriate rotation of the crankshaft, therefore, the ends  96  of the rods may be displaced into and out of engagement with a rear surface of the flange  29 , best seen in  FIG. 8 , so as to lock and unlock the door  10  when the door is in its closed position. At the same time, a locking plate  100  defined on or attached to the crank  86  is moved into and out of engagement with the flange rear surface. The door  10  may therefore be securely retained in its closed position at three separate locations by the ends  96  of the rods  92  and the locking plate  100 . 
   Referring now to  FIGS. 9 and 10 , operation of the overall locking mechanism of the door  10 , which locking mechanism includes the crank  86 , the rods  92 , and the plate  100  mentioned, will be described. A handle seat  112  is welded or otherwise secured to the exterior surface of the door  10 , and includes a central opening  114 . The central opening of the handle seat is configured so as to receive a handle  110 , which forms part of the locking mechanism, when that handle is in its inoperative or closed position.  FIG. 9  shows the handle  110  in its closed position, while  FIG. 10  shows the handle  110  in its operative or open position. 
   At its upper end  116 , the handle  110  is secured by a conventional ball joint and pin or other such coupling (not shown) to the crankshaft  88 , which extends through the door  10  to the crank  86 . The coupling is configured such that the handle  110  is permitted by the coupling to pivot outwardly, e.g. about an axis defined by the coupling pin, with respect to the door  10  but is rotationally fixed to the crankshaft  88 , e.g. by the pin, so that rotation of the handle produces rotation of the crankshaft which, in turn, causes rotational movement of the crank  86  and the locking plate  100  and longitudinal movement of the rods  92  with respect to the guides  94 . 
   The handle  110  also includes a first opening  120  roughly near the longitudinal midpoint thereof and a second opening  122  closer to its lower end  124 . A padlock post  126  is welded or otherwise secured to the door  10 , as best seen in  FIGS. 9 and 10 , and extends outwardly from the door  10 . When the handle  110  is in the closed position shown in  FIG. 9 , the padlock post  126  extends through the first handle opening  120 . The padlock post  126  includes a hole or bore  128  provided therein which is adapted to receive the shackle of a particularly configured, heavy gauge padlock, in a manner which will be described, which assists in locking the handle  110  in its closed position. 
   The padlock used is sufficiently small in size, and the diameter of the padlock post  126  is sufficiently large, that the shackle of the padlock closely matches the contour of the padlock post  126 , thereby making it impossible to place a bolt cutter between the padlock post and the shackle of the padlock. 
   A receptacle  130  is mounted to the interior of the door  10  and is adapted to receive an oblong plate or other locking element  132  of a handle mounted lock  136  disposed at the lower end  124  of the handle  110 . The locking element  132  can be operated by rotation of an actuation element to retain the end  124  of the handle in place or to permit movement of the end  124 . Operation of the handle-mounted lock  136 , by engagement and disengagement of the locking element  132  which will be described, is effected by rotating a hexagonally-shaped head  134  of a bolt-shaped actuation element. 
     FIG. 10  shows the locking element  132  disposed in a first position by solid lines and in a second position by phantom lines. The locking element  132  is rigidly connected, by a shaft of the actuation element, to the hexagonally shaped head  134 , which also forms part of the actuation element. When the locking element  132  is in its first position, the longer sides of the locking element are aligned with the body of the handle  110 , and the locking element  132  can pass through an oblong opening  140  defined in the door  10 . The handle  110  can be freely moved about the coupling at its upper end  116  between the inoperative or closed position shown in  FIG. 9  and the operative or open position when the locking element  132  is in its first position. If the locking element  132  is moved out of its first position and into a second position such as that illustrated in phantom in  FIG. 10 , the locking element  132  is prohibited from passing through the oblong opening  140 . After the locking element  132  has passed through the opening  140  so that it is received within the receptacle  130 , therefore, the locking element  132  can be moved out of its first position by rotation of the hexagonally-shaped head  134  to preclude movement of the handle  110  out of the inoperative or closed position shown in  FIG. 9 . Conversely, the locking element can also be moved from a second position back into its first position by rotation of the hexagonally shaped head  134 . Once the padlock has been removed from the padlock post  126 , therefore, a particular tool, such as a 7/16″ can wrench, is still required to produce the requisite rotation of the hexagonally shaped head  134  in order to get the door  10  open. Since such a tool is typically not readily available to the public, and since the particularly configured padlock is not susceptible to vandalism by bolt cutters, the handle  110  is redundantly locked in its closed position in a manner which is highly secure. 
   The invention can be used to house Mikom/Andrew and ADC fiber optic repeaters and the associated power transformers in a particularly advantageous manner, and defines a standard for a ground mounted, vandal-proof, highly secure, and ventilated electrical enclosure that meets NEMA (National Electrical Manufacturers Association) 3 rainproofing standards. In one preferred configuration, the invention is 53″ high by 22″ wide by 29″ deep. The lower compartment is 19″ high and designed to hold the power components associated with fiber optic repeaters in distributed antenna systems. The 39″ high upper compartment contains the sliding drawer assembly and is designed to securely house and provide ready access to a fiber optic repeater and, specifically, the Andrew/Mikom and ADC type components used in Nextel&#39;s Distributed Antenna System networks across the country. 
   The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications to the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons of ordinary skill in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.

Technology Category: h