Abstract:
A network cabinet comprising an electronic component a duct positioned therein. The electronic component has at least one exhaust vent and the duct defines first and second openings. The first opening aligns with the exhaust vent such that the duct receives exhaust therefrom and the duct extends from the first opening toward a side of the network cabinet such that the second opening faces the side of the cabinet to direct the exhaust thereto.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority to prior provisional patent application No. 60/805,157, filed Jun. 19, 2006. 
     
     FIELD OF INVENTION 
       [0002]    This invention relates to network cabinets for cable connections and more particularly to cooling systems for these cabinets for removal of heat generated by electronic equipment mounted therein. 
       BACKGROUND 
       [0003]    There is a need to provide cooling systems for cabinets which contain electronic equipment which generate heat. 
       SUMMARY OF THE INVENTION 
       [0004]    In one example, a network cabinet comprises an electronic component a duct positioned therein. The electronic component has at least one exhaust vent and the duct defines first and second openings. The first opening aligns with the exhaust vent such that the duct receives exhaust therefrom and the duct extends from the first opening toward a side of the network cabinet such that the second opening faces the side of the cabinet to direct the exhaust thereto. 
         [0005]    In another example, a method for venting a network cabinet comprises the steps of: positioning an electronic component within the network cabinet, the electronic component comprising an exhaust vent; positioning a duct within the network cabinet, the duct defining first and second openings; and aligning the first opening with the exhaust vent to receive exhaust from the electronic component and aligning the second opening to face a side of the network cabinet to direct the exhaust toward the side of the network cabinet. 
         [0006]    In another example, an exhaust duct system associated with a network cabinet comprises a duct positionable within the network cabinet. The duct defines an opening and comprises a means for mounting the duct to a portion of the network cabinet such that the opening is aligned with an exhaust vent of an electronic component to receive exhaust therefrom. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    Certain embodiments of the present invention are illustrated by the accompanying figures. It should be understood that the figures are not necessarily to scale and that details that are not necessary for an understanding of the invention or that render other details difficult to perceive may be omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein. 
           [0008]      FIG. 1  is a front perspective view of the network cabinet of the present invention; 
           [0009]      FIG. 2A  is a front perspective view of the base flame of the network cabinet of the present invention; 
           [0010]      FIG. 2B  is an enlarged partial exploded view of the front door mount and base frame shown in  FIG. 2A ; 
           [0011]      FIG. 2C  is an enlarged partial exploded view of the adjustable equipment rail and base frame shown in  FIG. 2A ; 
           [0012]      FIG. 3  is a cross-sectional view taken along line  3 - 3  in  FIG. 2A ; 
           [0013]      FIG. 4A  is a bottom perspective view of the base frame of  FIG. 2A  and top cover of the network cabinet of the present invention; 
           [0014]      FIG. 4B  is an enlarged partial view of the base frame and top cover shown in  FIG. 4A ; 
           [0015]      FIG. 5A  is a top view of the top cover of the network cabinet of the present invention; 
           [0016]      FIG. 5B  is an enlarged partial view of a cable entry knockout shown in  FIG. 5A ; 
           [0017]      FIG. 6  is a cross-sectional view taken along line  6 - 6  in  FIG. 2A ; 
           [0018]      FIG. 7A  is an exploded perspective view of the base frame, top cover, and side panels of the network cabinet of the present invention; 
           [0019]      FIG. 7B  is an enlarged partial exploded view of the base frame and side panel brackets shown in  FIG. 7A ; 
           [0020]      FIG. 8A  is a perspective view of the base frame, top cover, and side panels of the network cabinet of the present invention, with one side panel partially installed; 
           [0021]      FIG. 8B  is an enlarged partial view of the base frame, top cover, and side panel shown in  FIG. 8A ; 
           [0022]      FIG. 8C  is an enlarged partial view of the top cover and grounding clip shown in  FIG. 8B ; 
           [0023]      FIG. 9  is a cross-sectional view taken along line  9 - 9  in  FIG. 8A ; 
           [0024]      FIG. 10A  is a back perspective view of the network cabinet of the present invention; 
           [0025]      FIG. 10B  is an enlarged partial view of the door handle shown in  FIG. 10A ; 
           [0026]      FIG. 10C  is an enlarged partial view of the back of the door handle shown in  FIG. 10B ; 
           [0027]      FIG. 10D  is a back perspective view of the back doors of the network cabinet of the present invention with an alternative latch mechanism; 
           [0028]      FIG. 10E  is an enlarged partial view of the alternative latch mechanism shown in  FIG. 10D  in the open position; 
           [0029]      FIG. 10F  is an enlarged partial view of the alternative latch mechanism shown in  FIG. 10D  in the closed position; 
           [0030]      FIG. 11  is a cross-sectional view taken along line  11 - 11  in  FIG. 10A ; 
           [0031]      FIG. 12A  is a front perspective view of the network cabinet of the present invention, with the front door partially open; 
           [0032]      FIG. 12B  is an enlarged partial view of a safety hinge of the front door shown in  FIG. 12A ; 
           [0033]      FIG. 12C  is a back view of the safety hinge in  FIG. 12B ; 
           [0034]      FIG. 12D  is an enlarged partial view of a second safety hinge of the front door shown in  FIG. 12A ; 
           [0035]      FIG. 12E  is an enlarged partial view of a front door lifting mechanism of the front door shown in  FIG. 12A ; 
           [0036]      FIG. 12F  is a back perspective view of the front door of the network cabinet shown in  FIG. 12A  with an alternative latch mechanism; 
           [0037]      FIG. 12G  is an enlarged partial view of the alternative latch mechanism of the front door shown in  FIG. 12F ; 
           [0038]      FIG. 13  is a cross-sectional view taken along line  13 - 13  in  FIG. 12A ; 
           [0039]      FIG. 14A  is a front perspective view of the base frame of the network cabinet of the current invention with caster assemblies, cable management units, and slack management spools attached; 
           [0040]      FIG. 14B  is an exploded, enlarged partial view of a caster assembly shown in  FIG. 14A ; 
           [0041]      FIG. 15A  is a back perspective view of a right hand cable management unit; 
           [0042]      FIG. 15B  is a back perspective view of a left hand cable management unit; 
           [0043]      FIG. 16A  is an exploded partial enlarged view showing the attachment of a right hand cable management unit to the base frame of the network cabinet of the present invention; 
           [0044]      FIG. 16B  is all exploded partial enlarged view showing the attachment of a left hand cable management unit to the base frame of the network cabinet of the present invention; 
           [0045]      FIG. 17  is a cross-sectional view taken along line  17 - 17  in  FIG. 15B ; 
           [0046]      FIG. 18A  is an exploded partial enlarged view showing the attachment of a slack management spool to the base frame of the network cabinet of the present invention; 
           [0047]      FIG. 18B  is a side view of the slack management spool shown in  FIG. 18A ; 
           [0048]      FIG. 19  is a front perspective view of two network cabinets ganged together; 
           [0049]      FIG. 20  is a front perspective view of the network cabinets in  FIG. 19 , with the front doors open; 
           [0050]      FIG. 21  is a cross-sectional view taken along line  21 - 21  in  FIG. 20 ; 
           [0051]      FIG. 22  is a top rear perspective view of the base frame and top cover of the network cabinet of  FIG. 4A  wherein an electronic switching device is mounted along with an exploded view of the duct work of the present invention; 
           [0052]      FIG. 23  is a front perspective view of  FIG. 22  with side panel brackets; and 
           [0053]      FIG. 24  is a rear perspective view of  FIG. 23 . 
       
    
    
     DETAILED DESCRIPTION 
       [0054]    Referring to  FIG. 1 , one embodiment of the network cabinet  10  of the present invention is shown. The network cabinet generally includes a base frame  100 , top cover  200 , side panels  300 , back doors  400 , and front door  500 . When fully assembled, the exemplary network cabinet is approximately 32 inches wide, 40 inches deep, and 84 inches high and has 45 rack units with a 2,000 pound load rating. 
         [0055]    Referring to  FIG. 2A , an exemplary base frame  100  of the network cabinet  10  is shown. The base frame  100  is conductive and generally includes a pair of front vertical frame rails  105 , a pair of back vertical frame rails  110 , a pair of front to back base beams  115 , a pair of side to side base beams  120 , a pair of front to back top beams  125 , a pair of side to side top beams  130 , and front to back support beams  135 , all of which are typically steel. As can be seen in  FIG. 2A  and is described in more detail below, the front and back vertical frame rails  105 ,  110  are inset from the corners of the network cabinet  100 . This provides unobstructed space along all of the sides of the network cabinet  100  for cable management pathways. 
         [0056]    The side to side base beams  120  have a rectangular cross-section geometry and are positioned between and perpendicular to the front to back base beams  115 , which also have a rectangular cross-section geometry. The side to side base beams  120  are welded to the front to back base beams  115  to form a base for the network cabinet. The front vertical frame rails  105  and back vertical frame rails  110  have a generally “C” shaped cross-section geometry and are positioned vertically on the front to back base beams  115  and welded to the front to back base beams  115 . The side to side top beams  130  have a generally “U” shaped cross-section geometry and are positioned between and perpendicular to the front to back top beams  125 , which have a generally “C” shaped cross-section geometry. The side to side top beams  130  are welded to the front to back top beams  125  to form a support for the top cover. The front to back top beams  125  are positioned at the top end of the front and back vertical frame rails  105 ,  110  and welded to the front and back vertical frame rails  105 ,  110 . The front and back vertical frame rails  105 ,  110  are positioned so that they are set back from the corresponding ends of the front to back base beams  115 . The space created by setting the frame rails  105 ,  110  back from the ends of the front to back base beams  115  provides an area for cabling, etc., between the frame rails  105 ,  110  and the front and back doors  500 ,  400  when the network cabinet is fully assembled. 
         [0057]    The front to back support beams  135  have a generally “C” shaped cross-section geometry, are positioned between and perpendicular to corresponding front and back vertical frame rails  105 ,  110 , and are welded to the front and back vertical frame rails  105 ,  110 . By welding together all of the steel components of the base frame  100 , the base frame  100  is a single conductive bonded unit. A ground whip  25  is bonded, in this example, to front to back top beam  125  and is, in turn, connected at its opposing end to a main building ground. Ground whip  25  can also be attached to any other base frame  100  structural member to provide a single ground point for the base frame  100 . 
         [0058]    Referring to  FIGS. 2A and 2B , a pair of steel door mounts  15  are shown that have a generally “L” shaped cross-section geometry and are used to support the back and front doors  400 ,  500 . Each door mount  15  is attached to an end of each front to back base beam  115  by bolts  30  that extend through holes  16  in the door mounts  15  and thread into nuts  40  that are welded to end caps (not shown), which are attached and bonded to the ends of the front to back base beams  115 , such as by welding. In addition, as shown in  FIG. 2B , at one of the two attachment points the door mount  15  is also bonded to the front to back base beam  115  by placing an internal tooth lock washer  35  between the bolt  30  and the door mount  15 . The bolt  30  is inserted through the internal tooth lock washer  35  and through a hole  16  in the door mount  15  and is threaded into nut  40 . The internal tooth lock washer  35  has teeth that pierce the paint or coating on the door mount  15  and bite into the metal of the door mount  15  to provide a ground path between the door mount  15  and the front to back base beam  115  through washer  35 , bolt  30 , and nut  40 . An anti-oxidant paste could also be placed on the door mount  15 , between the door mount  15  and lock washier  35 , to prevent possible corrosion where the teeth of the lock washer  35  bite into the metal of the door mount  15 . Alternatively, a regular washer could be used and the area around the hole  16  could be masked off or a serrated head bolt could be used in place of the bolt  30  and internal tooth lock washer  35  to similarly provide a bond between door mount  15  and front to back base beam  115 . 
         [0059]    Referring to  FIGS. 2A. 2C , and  3 , steel adjustable equipment rails  20  are shown that have a generally, “L” shaped cross-section geometry and are used to mount equipment, such as patch panels, switches, or other network hardware equipment (not shown) in the network cabinet. As call best be seen in  FIG. 3 , the equipment rails  20  each have a series of mounting holes  23  that are used to mount equipment to the equipment rails  20 . In one example, the mounting holes  23  call be tapped holes that are threaded to accept a mounting bolt or screw (not shown) or in another example can be square holes that are adapted to accept a caged nut, which will then accept a mounting bolt or screw. In addition, as described in more detail below. the equipment rails  20  can be adjusted by sliding them forward and backward along the front to back support beams  135 . The equipment rails  20  enable heavy equipment to be mounted at four points and in the exemplary network cabinet  100  can accommodate mounting depths of up to 25.9 inches. 
         [0060]    Each equipment rail  20  extends approximately from a front to back base beam  115  to the corresponding front to back top beam  125  and is connected to each of the three front to back support beams  135  which are each positioned at different elevations opposing sides of the base frame  100 . The equipment rails are connected to two of the front to back support beams  135  by inserting a bolt  45  through a hole  21  in one side of the equipment rail  20  and through a slot  140  (see  FIG. 2C ) in the front to back support beams  135  so that the threaded end of the bolt  45  extends into a channel  145  formed by the front to back support beam  135 . A jam-nut  55  is positioned within the channel  145  and the bolt is threaded into the jam-nut  55 . The jam-nut  55  has an oblong configuration in which the length of the jam-nut  55  is greater than the width of the channel  145 , thereby preventing rotation of the jam-nut  55  within the channel  145 . The use of the jam-nut  55  allows the bolt  45  to be tightened without the need for a wrench or other tool to hold the nut securely within the channel  145 . In addition, the use of bolt  45  and jam-nut  55  allows easy loosening of tile connection between the adjustable equipment rails  20  and the front to back support beams  135 , allowing for easy adjustment of the equipment rails  20  alone front to back support beam  135 . 
         [0061]    In addition, as shown in  FIGS. 2C and 3 , at the third connection of equipment rail  20  to a front to back support beam  135 , the connection is bonded by placing an internal tooth lock washer  50  between the bolt  45  and the equipment rail  20  and a second internal tooth lock washer  51  between the jam-nut  55  and the front to back support beam  135 . The internal tooth lock washers  50 ,  51  have teeth that pierce the paint or coating and bite into the metal of the equipment rail  20  and front to back support beams  135 . An anti-oxidant paste could also be placed on the equipment rail  20  and front to back support beam  135 , underneath the lock washers  50 ,  51 , to prevent possible corrosion where the teeth of the lock washers  50 ,  51  bite into the metal of the equipment rail  20  and front to back support beam  135 . This provides a ground path from the equipment rail  20  to the front to back support beams  135  through the bolt  45 , washers  50 ,  51  and jam-nut  55 . This bonding makes adjustment of the equipment rails  20  more convenient since there are no jumper wires to disconnect and reconnect when the equipment rails  20  are moved. Alternatively, regular washers could be used and the area around the hole in the adjustable equipment rail  20  and the slot  140  in the front to back support beam  135  could be masked off or a serrated head bolt could be used in place of the bolt  45  and lock washer  50 . 
         [0062]    Referring to  FIGS. 4A and 4B , the top cover  200  is generally rectangular steel sheet having rolled over edges that is positioned on the front to back top beams  125  and side to side top beams  130  and secured to the front to back top beams  125 . Four steel threaded members  230  are welded to the bottom side of the top cover  200  and extend from the bottom side of the top cover  200  such that they align with holes or slots (not shown) in the top surfaces of the front to back top beams  125 . The threaded members  230  are aligned with and inserted into the holes in the front to back top beams  125  such that they extend through the holes. On three of the threaded members  230 , hex nuts  235  are threaded onto the threaded members  230  to secure the top cover  200 . On the fourth threaded member  230 , the top cover  200  is also bonded to the front to back top beam  125  by placing an internal tooth lock washer  240  between the hex nut  235  and the front to back top beam  125 . An anti-oxidant paste could also be placed on the front to back top beam  125 , underneath the lock washer  240 , to prevent possible corrosion where the teeth of the lock washer  240  bites into the metal of the front to back top beam  125 . This provides a ground path from the top cover  200  to the front to back top beam  125  through the threaded member  230 , hex nut  235 , and lock washer  240 . Alternatively, a regular washer could be used and the area around the hole in the front to back top beam  125  could be masked off or an internal tooth hex nut could be used in place of hex nut  235  and lock washer  240 . 
         [0063]    Referring to  FIGS. 5A and 5B , the top cover  200  also has a center knockout  205  and multiple cable entry knockouts  210 . The center knockout  205  can be removed to provide access to and ventilation for a fan mounted in the cabinet, for louvers, for cable entry, etc., and the cable entry knockouts  210  can be removed to provide cable entry access in an over-head cable deployment application. 
         [0064]    Each knockout  205 ,  210  is formed by cutting a slot  215  through the top cover  200  around the periphery of each knockout  205 ,  210 . The slot  215  is cut almost completely around the periphery of each knockout  205 ,  210 , except for the areas of the joining webs  225 , which connect the main portion of the top cover  200  to the knockouts  205 ,  210  and hold the knockouts  205 ,  210  in place prior to removal. Each knockout  205 ,  210  has a minimum of four joining webs  225 , as shown in  FIG. 5B . The use of at least four joining webs  225  securely holds the knockouts  205 ,  210  in place in the installed position, whereas typical larger-size knockouts in sheet-metal components have been loosely held with only two joining webs and have been susceptible to inadvertent removal. In addition, at the end of each portion of the slot  215 , there is all enlarged opening  220 , which is sized to accept common hand tool cutters that can be used to cut the joining webs  225 , which makes removal of the knockouts  205 ,  210  easier. 
         [0065]    Referring to  FIGS. 4A and 6 , four leveling legs  60  extend below the front to back base beams  115  to provide support and leveling capability for the network cabinet. As can best be seen in  FIG. 6 , each leveling leg  60  has a top portion  61  that extends through the top surface of the front to back base beam  115  and is accessible above the front to back base beam  115 . The top portion  61  has a slotted or hexagonal cross-section that can be used with a socket wrench or other similar tool to raise and lower the leveling legs  60 , as described below. Alternatively, the top portion  61  could be slotted so that it can be used with a screwdriver or other similar tool to raise and lower the leveling legs  60 . Each leveling leg  60  also has a threaded body portion  63 . The threaded body portion  63  is threaded through a nut  65  that is welded to a leveling leg support  70 , which is attached and bonded to the front to back base beam  115 , such as by welding. This secures the leveling leg  60  to the front to back base beam  115  and allows adjustment of the leveling leg  60 , as discussed below. The foot  64  of the leveling leg is positioned below the front to back base beam  115  and is the portion of the leveling leg  60  that rests on the ground or floor to provide support. 
         [0066]    To adjust the height or level the network cabinet, a socket wrench or other similar tool is placed on the top portion  61  and the leveling leg  60  is rotated. As the leveling leg  60  is rotated, the interaction of the threaded body portion  63  and the nut  65  will raise or lower the leveling leg  60  depending on the direction of rotation. In this fashion, adjustment of the height of the front to back base beam  115  off of the floor can be accomplished. Being able to access and rotate the leveling legs  60  from the top allows the leveling legs  60  to be easily adjusted without having to tip or move the network cabinet. It also assists with the installation/removal of optional casters, which is discussed in more detail below. Furthermore, when casters are not installed, the leveling legs  60  can be fully retracted into the front to back base beams  115  so that the front to back base beams  115  and side to side base beams  120  will sit on the ground and the cabinet load will be distributed. 
         [0067]    Referring to  FIGS. 7A ,  7 B,  8 A, and  9 , the side panels  300  are generally rectangular sheet steel that can be solid or perforated for aesthetics and air flow. Alternatively, rather than using a single side panel  300  per side of the network cabinet, multiple side panels could be used on each side. The side panels  300  have hooks  305  attached to the bottom inside surface of the side panels  300  and latches  315  attached to the top of the side panels  300 . 
         [0068]    To mount the side panels  300 , a bar  310  is attached between the front and back door mounts  15  by end brackets  312 . The bar  310  is also supported near its center by center bracket  311 , which is attached to the front to back base beam  115 . As can best be seen in  FIGS. 8A and 9 , the hooks  305  are placed over the bar  310  to support the side panel  300  and the side panel  300  is aligned. The side panel  300  is then rotated into a vertical position and the latches  315  secure the side panel  300  to a side flange  202  of the top cover  200 . Alternatively, the latches  315  can also have a locking assembly that allows the latches  315  to be locked into position once the side panels  300  have been mounted. 
         [0069]    As can best been seen in  FIG. 7B , a center bracket  320  is attached and bonded to the center front to back support beam  135  and side brackets  325  are attached and bonded to a front vertical frame rail  105  and a back vertical frame rail  110 . Trilobular screws  330  are inserted through holes  321  in the brackets  320 ,  325  and are threaded into the front to back support beam  135  and vertical frame rails  105 ,  110 , securing the brackets  320 ,  325  to the front to back support beam  135  and vertical frame rails  105 ,  110 . The trilobular screws  330  bond to the front and back support beam  135  and vertical frame rails  105 ,  110  by cutting threads into the metal of the front to back support beam  135  and vertical frame rails  105 ,  110 . An area around the holes  321  in the brackets  320 ,  325  is masked and left unpainted, thereby also bonding the trilobular screws  330  to the brackets  320 ,  325 . Alternatively, rather than masking portions around the holes  321 , a trilobular screw having teeth on the underside of the head that will cut into the metal of the brackets  320 ,  325  can be used. 
         [0070]    The brackets  320 ,  325  provide support for the side panels  300  and offset the side panels  300  from the front and back vertical frame rails  105 ,  110  and front to back support rails  135 , thereby providing easily accessible vertical cable management pathways between the side panels  300  and the front and back vertical frame rails  105 ,  100  and front to back support rails  135 . In addition, brackets  325  on each side of bracket  320  provide a guide or channel for placing cables extending in a vertical direction within the cabinet and proximate to the respective corners of the cabinet. 
         [0071]    Referring to  FIGS. 8A ,  8 B, and  8 C, the side panels  300  are bonded to top cover  200  through a grounding clip  335 . The ground clip  335  is attached to a masked, unpainted portion of the side flange  202  of the top cover  200 . Each side panel  300  also has a masked, unpainted portion of the inside surface that contacts the ground clip  335  and compressed the ground clip  335  once the side panel  300  is latched in place. The contact of the ground clip  335  with the masked, unpainted portions of the top cover  200  and side panel  300  bonds each side panel  300  to the top cover  200 . 
         [0072]    Alternatively, rather than using grounding clips  335  to bond the side panels  300  to the top cover  200 , the side panels  300  could be bonded to the base frame  100  through the bar  310  and hooks  305 . To provide bonding in this manner, one of the end brackets  312  (which is welded to the bar  310 ) would be attached to a door mount  15  so that a bond is created and one of the hooks  305  would be attached to the side panel  300  so that a bond is created, such as by welding or the use of internal tooth lock washers, trilobular screws, paint masking, etc. as described throughout. A bond would then be created between the bar  310  and the bonded hook  305  by paint masking the bar  310  in the area that will contact the hook  305 . 
         [0073]    Referring to  FIG. 10A , the back doors  400  are mounted to the back of the network cabinet  10  between the top cover  200  and the back door mount  15 . In the example shown, the back doors  400  are split doors and are generally rectangular sheet steel that can be solid or perforated for aesthetics and air flow. Alternatively, rather than using split doors, a single back door or any other type of door could be used as well. Each of the back doors  400  hinges open on pins at the top and bottom of the outside corners of the back doors  400 . 
         [0074]    Referring to  FIGS. 10A ,  10 B, and  10 C, in the example shown one of the back doors  400 ′ has a latch mechanism  405  that secures the door to the top cover  200  and back door mount  15 . The latch mechanism  405  has a door handle  410  that is accessible from the outside of the back door  400 ′ and can also have a cylinder lock  430  that call lock the door handle  410  in the closed position. On the inside of the back door  400 ′, the door handle  410  is connected to a cam plate  415  that can rotate as the door handle  410  is rotated. An upper rod  420  is attached to one end of the cam plate  415  and a lower rod  425  is attached to the other end of the cam plate  415 , opposite the upper rod  420 . The upper rod  420  extends generally vertically from the cam plate  415  up to the top cover  200  and the lower rod  425  extends generally vertically from the cam plate  415  down to the door mount  15 . When in the closed position the upper rod  420  extends into a hole in the top cover  200  and the lower rod  425  extends into a hole in the door mount  15 , thereby securing the back door closed. 
         [0075]    In the example shown in  FIGS. 10A ,  10 B, and  10 C, one of the back doors  400 ′ has a latch mechanism  405  and the opposite back door  400 ″ is overlapped by the back door  400 ′ with the latch mechanism to hold it in the closed position. Alternatively, rather than overlapping, both back doors  400 ′,  400 ″ could have latch mechanisms  405 . 
         [0076]    In another example, shown in  FIGS. 10D ,  10 E, and  10 F, one of the back doors  400 ′ again has a latch mechanism  405 A that secures the door to the top cover  200  and back door mount  15 . The latch mechanism  405 A has a door handle (not shown) that is accessible from the outside of the back door  400 ′ and can also have a cylinder lock  430 A that can lock the door handle in the closed position. On the inside of the back door  400 ′, the door handle is connected to a cam plate  415 A that can rotate as the door handle is rotated. An upper rod  420 A is attached to one end of the cam plate  415 A and a lower rod  425 A is attached to the other end of the cam plate  415 A, opposite the upper rod  420 A. The upper rod  420 A extends generally vertically from the cam plate  415 A up to the top cover  200  and the lower rod  425 A extends generally vertically from the cam plate  415 A down to the door mount  15 . When in the closed position, the upper rod  420 A extends into a hole in the top cover  200  and the lower rod  425 A extends into a hole in the door mount  15 , thereby securing the back door closed. 
         [0077]    Referring specifically to  FIGS. 10E and 10F , in the example shown, the back doors  400 ′,  400 ″ still over lap to hold the second door  400 ″ in the closed position, but also have an additional feature to provide extra security for the second door  400 ″. In the example shown, cam plate  415 A has a locking arm  416  that extends outward from and generally perpendicular to the axis of rotation of cam plate  515 A and back door  400 ″ has a plate  460  that includes a slot  465 , which is configured to receive locking arm  416 . Plate  460  can be a separate piece that is attached to back door  400 ″, such as by welding or screws, or plate  460  can be integrally formed with back door  400 ″. In addition, locking arm  416  can be shaped in a stair-step configuration towards the back door  400 ′ to move locking arm  416  away from the inside of the network cabinet  10 , which reduces the risk that locking arm  416  will pinch or catch cables or wiring that are in the cabinet  10 . 
         [0078]    As can be seen in  FIG. 10E , when the latch mechanism  405 A is in an open position, locking arm  416  extends downward and does not engage slot  465  and the back doors  400 ′,  400 ″ can be opened. Conversely, as can be seen in  FIG. 10F , when the latch mechanism  405 A is moved to a closed position, locking arm  416  rotates until it is generally horizontal and engages slot  465 . When in this position, the back door  400 ″ is secured by the overlap of back door  400 ′ over back door  400 ″ and also by the engagement of locking arm  416  with slot  465 . 
         [0079]    Referring to  FIG. 11 , each of the back doors  400  is bonded to the top cover  200  through a spring loaded hinge assembly  435 , which includes a generally cylindrical body  440 , hinge pin  445 , release arm  455 , and spring  450 . The body  400  is steel and is welded to the inside surface of the back door  400 . The hinge pin  445  is steel and is positioned inside the body  400 . The release arm  455  is generally “L” shaped, extends through a hole in the end of the body  440 , and threads into the hinge pin  445 . Spring  450  is positioned inside of the body  440  and is compressed between the hinge pin  445  and the end of the body  440 . Spring  450  biases the hinge pin  445  outward from the body  440  and allows the hinge pin  445  to be retracted when the release arm  455  is pulled. Hinge pin  445  extends from the end of the body  440 , through a hole in the top of the back door  400  and through bushing  260  in top cover  200 , where hinge pin  445  contacts a thread forming screw  255  that is bonded to the top cover  200 . 
         [0080]    To bond the thread forming screw to the top cover  200 , a steel ground angle  245  is welded to the inside surface of the top cover  200  and the thread forming screw  255  is threaded into the ground angle  245  and into a nut  250  that is welded to the ground angle  245 , thereby providing a bond between the top cover  200  and the screw  255 . 
         [0081]    To install or remove the back door  400 , the release arm  455  is pulled downward, which compresses the spring  450  and retracts the hinge pin  445  into the body  440 . With the hinge pin  445  below the level of the bushing  260 , the back door  400  can be placed in position or removed. Once the back door  400  is in position, the release arm  455  is released and the spring  450  pushes the hinge pin  445  outward through tile bushing  260  until the hinge pin  445  contacts the screw  255 . 
         [0082]    The spring loaded hinge assembly  435  provides the hinge mechanism for the back door  400  and also provides a positive grounding path when the back doors  400  are installed. This allows the removal of the back doors  400  without the need of disconnecting any grounding jumper wires. 
         [0083]    Referring to  FIGS. 2A and 2B , the door mounts  15  have holes  18  that are inset from the bushings  600  that receive the bottom fixed hinge pin for the back doors  300 . Although  FIGS. 2A and 2B  show the door mount  15  for the front door  500 , the two door mounts  15  are mirror images of each other and the door mount  15  for the back doors  400  contain identical holes  18 . Referring to  FIGS. 4A ,  4 B, and  11 , the top cover  200  has holes  265  that are inset from the bushings  260  that receive the hinge pin  445  of the spring loaded hinge mechanism  435 . Each of the holes  18  in the door mounts  15  are aligned in a generally vertical axis with a corresponding hole  265  in the top cover  200  and provide a storage mechanism for a back door  400  that has been removed. 
         [0084]    For example, as described above, a back door  300  can be removed by pulling downward on the release arm  455 , which retracts the hinge pin  445  and allows the back door  300  to be tilted and removed. Rather than having to lean the removed back door  300  on the cabinet  10  or against a wall or other equipment where it can he bumped into or knocked over, the removed back door  300  can be stored using holes  18  and  265  in the door mount  15  and top cover  200 . To store the removed back door  300 , the opposite back door is opened the fixed hinge pin on the bottom of the removed back door  300  is inserted into the hole  18  in the door mount  15  nearest tile bushing  600  of the open back door, and the hinge pin  445  of the spring loaded hinge mechanism  435  is inserted into the corresponding hole  265  in the top cover  200  by pulling downward on the release arm  455 . 
         [0085]    Referring to  FIG. 12A , front door  500  is mounted to the front of the network cabinet  10  between top cover  200  and the front door mount  15 . In the example shown, the front door  500  is generally rectangular sheet steel that can be solid or perforated for aesthetics and air flow, is dual hinged, as described in more detail below, and can be opened from either the left or right side giving full access to either the left or right rack and vertical cable management channels without having to remove front door  500 . Alternatively, rather than using a single dual hinged door, split doors, a single hinged door, or any other type of door could be used as well. 
         [0086]    Referring to  FIG. 12A , front door  500  has two latch mechanisms  505 , one on each side of the front door  500 . The latch mechanisms  505  have a door handle  510  (as shown in  FIG. 19 ), cam plate  515 , upper rod  520 , and lower rod  525 , and are substantially identical in operation to the latch mechanism  405  described above for the rear doors  400  (see  FIGS. 10B and 10C ). The latch mechanisms  505  can also have a cylinder lock  530  (as shown in  FIG. 19 ), which can lock the door handle  510  in the closed position. 
         [0087]    Referring to  FIG. 12A , at each top and bottom corner of the front door  500  (four positions total) is a locking hinge assembly  535 .  FIGS. 12B and 12D  show the locking hinge assemblies  535  on the bottom corners of the front door  500  and it will be understood that the assemblies on the top corners are identical to those described herein for the bottom corners.  FIG. 12C  show the backside of the latch mechanism shown in  FIG. 12B . Each locking hinge assembly  535  includes a hinge lever  540 , hinge support  542 , hinge pin  545 , an inner lever stop  555 , and an outer lever stop  570 . As used herein, an inner lever stop  555  is the lever stop that is closest to the hinge pin  545  and an outer lever stop  570  is the lever stop that is furthest from the hinge pin  545 . 
         [0088]    The hinge support  542  has a generally vertical wall  543  that is attached to the front door  500 , such as by welding, with screws, etc., and a generally horizontal wall  544  the extends generally perpendicular from the top of the vertical wall  543 . The hinge lever  540  is mounted to the vertical wall  543  of hinge support  542  by pin  560  such that lever arm  540  can rotate about pin  560 . Hinge lever  540  is also rotatably connected to a lower rod  525  (or upper rod  520  depending on which locking hinge assembly) at one end and to tile hinge pin  545  at the end opposite the lower rod  525 . The hinge pin  545  extends generally vertically through the front door  500  and through the horizontal wall  544 . 
         [0089]    A lever stop hinge pin  550 , as seen in  FIG. 12C , is attached to the front door  500  and the lever stops  555 ,  570  are mounted onto the lever stop hinge pin  550  such that the lever stops  555 ,  570  can rotate about the hinge pin  550 . Each of the lever stops  555 ,  570  has a generally vertical stop arm  556 ,  571  and a generally horizontal release arm  557 ,  572 . A torsion spring  565  is mounted on the lever stop hinge pin  565  and has ends that extend out to the stop arms  556 ,  571  of the lever stops  555 ,  570  to bias the lever stops  555 ,  570  into a forward position. 
         [0090]    In operation, when the front door  500  is closed (the closed position is defined as both top corners of the front door  500  seated against the top cover  200 , both bottom corners of the front door  500  seated against the door mount  15 , and all hinge pins  545  are engaged) the upper and lower rods  520 ,  525  are pulled towards the center of the front door  500 , thereby rotating the lever arms  540  and extending the hinge pins  545  into their corresponding bushings  600  in the door mount  15  or top cover  200 . Therefore, the hinge pins  545  in each of the four corners of the front door  500  engage the bushings  600  in the door mount  15  or top cover  200  and the front door  500  is fully secured. In addition, when in the closed position, the door mount  15  or top cover  200  will push against the release arms  557 ,  572  of both lever stops  555 ,  570 , thereby disengaging the stop arms  556 ,  571  of both lever stops  555 ,  570  from the hinge lever  540 . This allows the hinge lever  540  to rotate freely in either direction. Referring specifically to  FIG. 12B , when a door handle is rotated from a closed to an open position the lower rod  525  is lowered, the hinge lever  540  is rotated counter-clockwise about pin  560 , and the hinge pin  545  is raised. This enables the front door  500  to be hinged open about the hinge pins  545  in the opposite side. Conversely, when the lower rod  525  is raised (e.g. the door handle is moved from an open to a closed position), the hinge lever  540  will rotate clockwise about pin  560  and lower the hinge pin  545 . 
         [0091]    Referring specifically to  FIGS. 12B and 12D , operation of the locking hinge assemblies  535  is shown when the left side of the front door is unlocked and the front door is opened from left to right (as seen when facing the front of the network cabinet  10 ), as shown in  FIG. 12A .  FIG. 12B  shows the operation of the locking hinge assemblies  535  on the side of the front door  500  that remains engaged and  FIG. 12D  shows the operation of the locking hinge assemblies  535  on the side of the front door  500  that is disengaged. 
         [0092]    Referring to  FIG. 12B , when the front door  500  is moved from the closed position the door mount  15  no longer pushes against the release arms  557 ,  572  of the lever stops  555 ,  570  and the torsion spring attempts to push the lever stops  555 ,  570  into a forward position. Because the hinge lever  540  is still in the locked position, the inner lever stop  555  is blocked by the hinge lever  540  and cannot rotate forward. However, the outer lever stop  570  is not obstructed by the hinge lever  540  and is pushed into a forward position by the torsion spring. When the outer lever stop  570  is in the forward position, the stop arm  571  is positioned underneath the hinge lever  540 , thereby preventing the hinge lever  540  from rotating. Therefore, in this position, if a user were to attempt to turn the door handle (attempting to move the lower rod  525  downward) the stop arm  571  prevents the hinge lever  540  from moving, thereby preventing the door handle from being moved. This prevents an engaged hinge from being accidentally disengaged if the opposing hinge is disengaged and the front door  500  is open. Should this accidental disengagement not be prevented, front door  500  could easily fall onto and injure a person positioned in front of the network cabinet  10 . 
         [0093]    Referring to  FIG. 12D , to move the front door  500  from the closed position the locking hinge mechanisms  535  on the side to be opened must be disengaged. When a user turns the door handle the lower rod  525  is pushed down, which rotates the hinge lever  540  and pulls back the hinge pin  545 . After the locking hinge mechanisms  535  have been disengaged and the front door  500  is moved from the closed position, the door mount  15  no longer pushes against the release arms  557 ,  572  of the lever stops  555 ,  570  and the torsion spring attempts to push the lever stops  555 ,  570  into a forward position. Because the hinge lever  540  has been moved from the locked position, the outer lever stop  570  is blocked by the hinge lever  540  and cannot rotate forward. However, the inner lever stop  555  is not obstructed by the hinge lever  540  and is pushed into a forward position by the torsion spring. When the inner lever stop  555  is in the forward position, the stop arm  556  is positioned underneath the hinge lever  540 , thereby preventing the hinge lever  540  from rotating. Therefore, in this position, if a user were to attempt to turn the door handle (attempting to move the lower rod  525  upward) the stop arm  557  prevents the hinge lever  540  from moving, thereby preventing the door handle from being moved. This prevents the closing of the door handle until the front door  500  is in the fully closed position such that lever stop  555  has been pushed backward thereby unobstructing hinge lever  540  allowing hinge pin  545  to be lowered through and fully engage bushing  600 . 
         [0094]    As can be seen from the above description the locking hinge assemblies  535  require that the front door  500  be in a closed position before the user can change the state of the front door  500  (e.g. engage or disengage the locking hinge assemblies  535 ). This accomplishes two important goals: (1) it prevents unexpected and accidental removal of the front door  500  (when one side is open, the other side is locked and cannot be disengaged until the front door  500  is closed): and (2) it prevents a user from mistakenly thinking that the front door  500  is closed when it is still ajar (the door handle cannot be moved into the closed position until the front door  500  is completely closed and the lever stops allow movement of the hinge lever). 
         [0095]    To remove the front door  500 , the front door  500  is first placed in the closed position. In this position all of the inner and outer lever stops  555 .  570  of all of the locking hinge assemblies  535  are pushed into a retracted position allowing all of the hinge levers  540  to move freely. While in the closed position, both of the door handles are turned which will disengage all of the locking hinge assemblies  535  by extending the upper and lower rods  520 ,  525  and retracting the hinge pins  545  from their respective bushings  260 ,  600 , allowing removal of the front door  500 . Once the front door  500  has been removed, the inner lever stops  555  are move into their forward position by the torsion spring  565 , thereby obstructing the hinge lever  540  and preventing the door handles from being turned. To install the front door  500 , the above process is reversed. The front door  500  is placed against the door mount  15  and top cover  200  such that the hinge pins  545  are aligned with their respective bushings  260 ,  600 . In this position, the door mount  15  and top cover  200  will push the inner lever stops  555  backwards and out of the way of the hinge lever  540 , thereby allowing the hinge lever  540  to move freely. Both of the door handles are then turned to retract the upper and lower rods  520 ,  525  and thereby extend the hinge pins  545  into their respective bushings  260 ,  600 . 
         [0096]    Referring to  FIG. 12E , the engagement between the hinge pin  545  of the front door  500  and the door mount  15  is shown. The hinge pin  545  extends through and engages a bushing  600  that is positioned in a hole in the top of the door mount  15 . A lifting, screw  605  is threaded into the bottom portion of the door mount  15  just below, the bushing  600  that engages the hinge pin  545 . As the door handle is moved into the closed position, the hinge pin  545  moves down through the bushing  600  and contacts the lifting screw  605 . After the hinge pin  545  contacts the lifting screw  605 , the hinge pin  545  continues to move downward and lifts the front door  500  off of the bushing  600 . Therefore, the front door  500  rides on the hinge pin  545 , which provides clearance between front door  500  and door mount  15  when closing the front door  500  and compensates for door sag and/or worst case tolerance stack-ups. 
         [0097]    With the weight of front door  500  riding on hinge pin  545  (rather than on bushing  600 ), there is a constant force on the bottom hinge pins  545  attempting to push hinge pins  545  into a retracted position. If the door handle is not fully engaged when the front door  500  is in the closed position, the force on the hinge pins  545  could cause the door handle to rotate towards an open position and possibly disengage locking hinge assemblies  535 . To prevent this from happening an overcame latch mechanism can be used. Referring to  FIGS. 12F and 12G , the overcame latch mechanism  505 A is substantially identical to latch mechanisms  505  described above in that it has a door handle (not shown), a cam plate  515 A connected to the door handle, and upper and lower rods  520 ,  525  that are connected to lobes of the cam plate  515 A. The main difference between latch mechanism  505  and latch mechanism  505 A is the design of the cam plate  515 A. The cam plate  515  in latch mechanism  505  has lobes that are aligned and extend outward from the axis of rotation of the cam plate  515 . Conversely, the cam plate  515 A in the overcame latch mechanism  505 A has lobes  517 ,  518  that are generally perpendicular to each other and extend outward from the axis of rotation of the cam plate  515 A. 
         [0098]    As can best be seen in  FIG. 12G , when the front door  500  is in the closed position and the locking hinge assemblies  535  are engaged, the lobe  517  that is connected to lower rod  525  (and therefore bottom hinge pin  545 ) is extending substantially vertically. In operation, a force exerted on the lower hinge pin  545  that attempts to retract the hinge pin  545  (such as the weight of the front door  500  riding on hinge pin  545 ) will place a downward force on the lower rod  525 . However, since lobe  517  is oriented vertically, this downward force on lower rod  525  will not cause the cam plate  515 A (and therefore the door handle) to rotate. In order to rotate the door handle and cam plate  515 A, a positive rotational force must be placed on the door handle to move the lobe  517  from a vertical position. This design prevents the door cam plate  515 A and door handle from rotating due to the force exerted by the weight of front door  500  on lower hinge pin  545 . 
         [0099]    Referring to  FIG. 13 , the front door  500  is also bonded to the top cover  200  by spring loaded bearing assemblies  610 . Two spring loaded bearing assemblies  610  are positioned one at opposite corners of the top cover  200 , one near each bushing  600  and hinge pin  545 . In positioning spring loaded bearing assembly  610  near hinge pin  545 , bearing assembly  610  maintains contact with front door  500  as front door  500  is swung to an open position. By using two bearing assemblies  610 , the front door  500  stays bonded to the top cover  200  when closed, open to the left, or open to the right. Each spring loaded bearing assembly  610  has a generally cylindrical body  615 , a ball bearing  620 , a face plate  625 , and a spring  630 . Body  615  is steel and has external threads that permit body  615  to be screwed into paint masked compatible threads in the top cover  200  until the steel face plate  625  is flush with the top cover  200 , which provides a bond between the spring loaded bearing assembly  610  and the top cover  200 . Ball bearing  620  is steel and is biased towards face plate  625  by steel spring  630  and protrudes beyond face plate  625  so that it contacts the top of the front door  500 . The top of the front door  500  is masked where the ball bearing  620  will contact the front door  500 , which provides a bond between the bearing assembly  610  and the front door  500 . The bearing assemblies are positioned close enough to the bushing  600  and hinge pin  545  so that the front door  500  can open to approximately 160 degrees while maintaining the bond between the front door  500  and the top cover  200 . The use of the bearing assemblies  610  to create the bond between the front door  500  and the top cover  200  allows for the removal of the front door  500  without the need to disconnect any jumper wires. 
         [0100]    Alternatively, as can be seen in  FIGS. 12B and 12E , rather than bonding the front door  500  to the base frame  100  through a spring loaded bearing assembly  610  in the top cover  200 , the front door  500  can be bonded to the base frame  100  through the lifting screw  605  in the door mount  15 . To bond the front door  500  in this manner, the lifting screw  605  is first bonded to the door mount  15 . This can be done by using a trilobular lifting screw, by placing an internal tooth lock washer between the head of the lifting screw and the door mount, by using a lifting screw that has teeth on the under side of the head, or by paint masking the portion of the door mount that will contact the head of the lifting screw. The hinge pin  545  is then bonded to the front door  500 , such as by attaching a jumper wire between the hinge pins  545  and the front door  500 . Therefore, when the hinge pins  545  contact the lifting screws  605 , a bond is created between the front door  500  and the door mount  15  through the jumper wire, hinge pins  545 , and lifting screws  605 . 
         [0101]    As can be seen from the detailed descriptions above, when the network cabinet  100  is fully assembled, all of the components of the cabinet are bonded together. The components that make up the base frame  100  are all bonded by welding them together. The door mounts  15 , equipment rails  20 , and top cover  200  are bonded to the base frame by use of internal tooth lock washers. The side panels  300  are bonded to the top cover  200  by use of grounding clips  335 . The back doors  400  are grounded to the top cover  200  by spring loaded grounding hinge mechanisms  435 . Finally, the front door  500  is grounded to the top cover  200  by the spring loaded bearing assemblies  610 . By bonding all of the components of the cabinet together, separate grounding jumper wires are not required and the network cabinet  100  is completely grounded and requires only a single point of contact with the main building ground (the ground whip  25 ). 
         [0102]    Referring to  FIG. 14A , the network cabinet  10  can also include caster assemblies  700 , cable management fingers  800 , and slack management spools  900 . 
         [0103]    Referring to  FIGS. 14A and 14B , the caster assemblies  700  are mounted to the sides of the front and back vertical frame rails  105 ,  110 , alleviating the need to tip or turn the network cabinet  10  or base frame  100  in order to install, remove, or repair the caster assemblies  700 . The caster assemblies  700  include a body  705 , which is steel and is formed by a first wall  710 , a second wall  715  that extends generally perpendicular to the attachment wall  710 , and a pair of support walls  720  that extend between the first wall  710  and second wall  715  to provide strength and rigidity to the body  705 . 
         [0104]    A standard caster wheel  730  is attached to the second wall  715  of the body  705 . The first wall  710  of the body  705  has a pair of holes  711  and a wall member  712  that extends from the first wall  710  to form a slot  713  between the wall member  712  and the first wall  710 . 
         [0105]    As shown in  FIG. 14B , to install a caster assembly  700 , the base frame  100  is raised by rotating the leveling legs  60 . The first all  710  of the caster assembly  700  is placed against the back vertical frame rail  110  such that the wall member  712  extends into an aperture  111  in the vertical frame rail  110 . The caster assembly  700  is then lowered such that a tongue  112  formed in the aperture  111  engages the slot  713  formed between the wall member  712  and the first wall  710  and holes  711  in the first wall  710  are aligned with holes  113  that are formed in the back vertical frame rail  110 . A pair of bolts  725  are inserted through the holes  711  in the first wall  710  and the holes  113  in the back vertical frame rail  110  and are threaded into a jam-nut  114  that is welded to the back vertical frame rail  110 . The base frame  100  is then lowered by rotating the leveling legs  60  until the base frame rests on the caster assemblies  700 . In addition to attaching the caster assembly  700  to the back vertical frame rail  110 , the bolts  725  and jam-nut  114  also provide bonding between the caster assembly  700  and the back vertical frame rail  110 . To create the bond, the bolts  725  have serrations or teeth on the underside of the head that bite through any paint into the metal of the body  705  to provide a bond between the body  705  and the bolts  725 . Alternatively, standard bolts could also be used with internal tooth lock washers to provide the bond or standard bolts could be used and the area around the holes  711  could be paint masked to provide the bond. 
         [0106]    Referring to  FIGS. 14A. 15A , and  15 B, multiple left hand cable management units  800  and right hand cable management units  805 , which are mirror images of each other, can be mounted to the front and back faces of the front vertical frame rails  105 A.  105 B and the front and back faces of the back vertical frame rails  110 A,  110 B. As used herein, the front faces of the front and back vertical frames rails  105 A,  105 B,  110 A, and  110 B are the faces that face outward from base frame  100  and are directly accessible from tile outside of the base frame  100 . The back faces of the front and back vertical frame rails  105 A,  105 B,  110 A, and  110 B are the faces that are opposite the front faces, face inward towards the inside of the base frame  100 , and are generally accessible from the inside or sides of the base frame  100 . For convenience,  FIG. 14A  shows the left and right hand cable management units  800 ,  805  mounted only to the front and back faces for the front vertical frame rails  105 A and  105 B. 
         [0107]    As described in more detail below, the left hand cable management units  800  would be mounted to the front faces of tile left side front vertical frame rail  105 A (left side when facing the cabinet from the front) and left side back vertical frame rail  110 A (left side when facing the cabinet from the back) and to the back faces of the right side front vertical frame rail  105 B and right side back vertical frame rail  110 B. Right hand cable management units  805  would be mounted to the front faces of the right side front vertical frame rail  105 B and right side back vertical frame rail  110 B and to the back faces of the left side front vertical frame rail  105 A and left side back vertical frame rail  110 A. Five cable management units  800 ,  805  can be mounted oil the front faces of the front and back vertical frame rails  105 A,  105 B,  110 A, and  110 B and four cable management units  800 ,  805  can be mounted in the back faces of the front and back vertical frame rails  105 A,  105 B,  110 A, and  110 B. 
         [0108]    As can best be seen in  FIGS. 15A and 15B , each cable management unit  800 ,  805  is molded plastic and includes a base  810  and nine fingers  815  that protrude and extend from the base  810 . Each finger  815  has a generally vertically oriented cable retainer  816  at its distal end (opposite the base  810 ) that prevents cables from spilling out of the fingers  815  and provides approximately 6.2 inches of cable management length (shown as A in  FIG. 15A ) between the base  810  and cable retainers  816 . Each finger  815  has a semi-circular cross-section in which the outside surface  820  (the surface that faces outside the base frame  100  when installed and will contact cables) is solid and has a bend radius of approximately 0.25 inches and the inside surface  821  (the surface that laces inside the base frame  100  when installed) is cored out to make the fingers  815  generally hollow. The bend radius of the outside surface  820  provides for the management of cable without any sharp corners which can damage the cables. Conversely, the inside surface  821  does not generally contact the cables and therefore can be designed without bend radii and can be cored out for manufacturability purposes. 
         [0109]    The spacing between the tops of adjacent fingers  815  is approximately 1.75 inches (shown as B in  FIG. 15B ), which is equivalent to one rack unit (“RU”). Each finger  815  has a height of approximately 0.5 inches, which provides approximately 1.25 inches of cable management height (shown as C in  FIG. 15B ). The finger height and spacing combine to allow for management of 48 Cat 6 cables, 24 cat6A cables, or other types of cabling, such as communication cabling, in each RU. The area where the base  810  meets each finger  815  also has a bend radius of approximately 0.3 inches. 
         [0110]    Referring additionally to  FIGS. 16A and 16B , each cable management unit  800 ,  805  includes buttons  825  that protrude from the back surface of the base  810 , opposite the fingers  815 . The buttons  825  are adapted to engage corresponding apertures  150  in the faces of the front and back vertical frame rails  105 ,  110  to mount the cable management units  800 ,  805  to the vertical frame rails  105 ,  110 . The buttons  825  are inserted into the corresponding apertures  150  and the cable management unit  800 ,  805  is pushed down to snap it into place. This allows the manual assembly and removal of the cable management units  800 ,  805  with no additional fasteners or tools. In addition, when multiple cable management units are mounted a gap of approximately 0.75 inches is left between adjacent units to allow for removal of individual units without having to remove units mounted above. 
         [0111]    As can best been seen in the enlarged partial views in  FIGS. 16A and 16B , on each cable management unit  800 ,  805  one of the buttons  825  will also include a protrusion  830  that extends laterally from one side of the button. In the example shown, the protrusion  830  extends from the top of the button and is skewed to the left for left hand cable management units  800  and skewed to the right for right hand cable management units  805 . This protrusion  830  is adapted to coincide with a slot  155  that extends from one side of an aperture  150 . One button on each cable management unit  800 ,  805  will have a protrusion  830  and only selected apertures  150  in the vertical frame rails  105 ,  110  will have slots  155 , which acts as a keying feature to prevent cable management units  800 ,  805  from being mounted on the wrong side of a vertical frame rail  105 ,  110  or from being mounted upside down. Having the slots  155  only in predetermined apertures  150  also requires that the cable management units  800 ,  805  be mounted in predetermined positions. Alternatively, all of the buttons  825  could have protrusions  830  and all apertures  150  could have slots  155 . This would allow the vertical positioning of the cable management units  800 ,  805  anywhere along a vertical frame rail while still preventing the mounting on the wrong side of a vertical frame rail or mounting upside down. 
         [0112]    As can best be seen in  FIGS. 15A ,  15 B, and  17 , each cable management unit  800 ,  805  also has a cantilevered locking finger  835  formed in the back surface of the base  810 . The outside surface of the locking linger  835  has a shallow inclined lead in face  840 , which is angled from the back surface approximately 20-40 degrees (lead in angle shown as D in FIG.  17 ), and a steep inclined lead out face  845 , which is angled from the back surface approximately 30-50 degrees (lead out angle shown as E in  FIG. 17 ). The locking finger  835  and faces  840 ,  845  are adapted to engage and snap into a locking slot  160  in the vertical frame rails  105 ,  110  (see  FIGS. 16A and 16B ) to secure the cable management units  800 ,  805  to the vertical frame rails  105 ,  110 . The shallow lead in angle D allows for easy mounting of the cable management units  800 ,  805 , while the steep lead out angle E provides more resistance so that the cable management units  800 ,  805  can be, but are not easily, removed. 
         [0113]    Referring to  FIGS. 14A ,  18 A, and  18 B, slack management spools  900  can also be mounted to the front and back vertical frame rails  105 ,  110  via brackets  905 . 
         [0114]    Referring specifically to  FIG. 18 , a slack management spool  900  is shown that, in this example, is plastic and includes a generally cylindrical spool body  950 , a stop wall  955  formed at one end of the spool body  950 , and a mounting wall  960  formed at the second end of the spool body  950  opposite the stop wall  955 . The mounting wall  960  has a pair of generally cylindrical protrusions  965  that are adapted to engage mounting holes in the brackets  905 , as seen in  FIG. 18A  and as discussed in more detail below. Each of the protrusions  965  has a first section  966  that extends from the surface of the mounting wall  960  and has a first dimension and a second section  967  at the end of the first section  966  that has a second dimension, which is greater than the first dimension. In this example, first section  966  and second section  967  are generally circular in design, wherein the first and second dimensions are diameters. 
         [0115]    Referring specifically to  FIG. 18A , the mounting of a slack management spool  900  to a front vertical frame rail  105  by a bracket  905  is shown. The bracket  905 , in this example, is steel and is generally “L” shaped having a first wall  910  and a second wall  915  that extends generally perpendicular to the first wall  910 . The first wall  910  has a hole  911  and a wall member  912  that extends from the first wall  910  to form a slot  913  between the wall member  912  and the first wall  910 . The second wall  915  has a pair of mounting holes  916  that are adapted to receive and secure the protrusions extending from the mounting wall  960  of the slack management spools  900 . 
         [0116]    To mount a bracket  905  to the front vertical frame rail  105 , the first wall  910  of the bracket  905  is placed against the front vertical frame rail  105  such that the wall member  912  extends into an aperture  106  in the front vertical frame rail  105 . Apertures  106  are positioned spaced apart along the vertical frame rails  105 ,  110 . In this example, four apertures  106  are provided in each vertical frame rail  105 ,  110 , as can be seen in  FIG. 14A . The bracket  905  is then lowered such that a tongue  107  formed in the aperture  106  engages the slot  913  formed between the wall member  912  and the first wall  910 . The bracket  905  is lowered until the hole  911  in the first wall  910  is aligned with a hole  108  formed in the front vertical frame rail  105 . A trilobular screw  920  is inserted through the hole  911  in the first wall  910  and is threaded into the hole  108  in the front vertical frame rail  105 . The trilobular screw  920  provides a bond to the front vertical frame rail  105  by cutting threads into the metal of the front vertical frame rail  105 . To provide a bond between the trilobular screw  920  and the bracket  905 , the trilobular screw  920  has serrations or teeth on the underside of the head that bite into the metal of the bracket  905 . Alternatively, a standard bolt could be used with an internal tooth lock washer or a standard bolt could be used and the area around the hole  911  could be paint masked and the area within the hole  108  could be paint masked as well. 
         [0117]    A slack management spool  900  is then mounted to tile bracket  905  by inserting the protrusions  965  extending from the mounting wall  960  through the mounting holes  916  in the bracket  905  and sliding the spool  900  downward until the first section  966  of the protrusions  965  engage the mounting holes  916 . 
         [0118]    Referring to  FIGS. 19-21 , there is shown two network cabinets  10  that are ganged, or joined, together. To gang two network cabinets  10  together the left side panel  300  of the right cabinet is removed and the right side panel  300  is removed from the left cabinet. The cabinets are then positioned next to each other such that the sides with side panels  300  removed are positioned adjacent one another. The top covers  200  of the adjacent network cabinets  10  are secured together by inserting bolts through holes in the adjacent side flanges  202  (not shown in  FIGS. 19-21 ) of the top covers  200  and threading nuts onto the bolts to secure the top covers  200  together. Generally “L” shaped steel brackets  660  are also bolted or screwed to the adjacent ends of the front and back door mounts  15 . In addition, generally “U” shaped double spool brackets  970  could also he attached between the adjacent front vertical frame rails  105  and back vertical frame rails  10  of the ganged cabinets. 
         [0119]    Referring specifically to  FIG. 21 , the cross hatched areas (side cable management pathways  640  and center cable management pathway  650 ) show the cable management pathways that are created is a result of inset frame structure of the network cabinets  10 . The side cable management pathways  640  are bounded by the side panels  300  on the outside and the front and back vertical frame rails  105 ,  110  and front to back support beams  135  on the inside. The center cable management pathway  650  is a larger cable management pathway that is bounded on the left and right by the adjacent front and back vertical frame rails  105 ,  110  and front to back support beams  135 . Hinging the front doors  500  outward (as shown in  FIG. 21 ) provides clear access to the center cable management pathway  650 . Hinging the front doors  500  inward provides clear access to the corresponding side cable management pathways  640 , which can also be clearly accessed by removing the corresponding side panel  300 . 
         [0120]    Referring now to  FIGS. 22-24  one example of network cabinet  10  having an air flow management system is shown. The network cabinet  10  is shown without its side panels  300  and front and back doors  500 .  400 ′ and  400 ″. The structure of network cabinet  10  has been discussed in detail hereinabove. 
         [0121]    Different types of electronic equipment components may be mounted in network cabinet  10 . A common electronic component may include a network without such as a Cisco 6500 or 9500 Series Network Switch. In this example, electronic equipment  1005 , a Cisco 6500 Series Network Switch is mounted to adjustable mounting rails  20 . Such network switches generate heat while in operation. In order for the switches, cable connections, other electronic equipment and cables positioned within the network cabinet to operate efficiently, heat generated by electronic equipment  1005  must be removed from the network cabinet. 
         [0122]    Electronic equipment  1005 , such as the Cisco 6500 switch, typically have fans positioned within the equipment that generate air flow over components that are generating heat within the switch device. In one instance, these fans (not shown) draw air into front intakes  1010 , as seen in  FIG. 23 . The front intakes  1010  are positioned facing what is generally referred to as a cool aisle. The cool aisle will often be defined as an aisle formed by the front portions of network cabinets. 
         [0123]    The air pulled into front intakes  1010  flows through electronic equipment  1005  in a front to the back pattern to cool tile heat generating components therein. For example, with the Cisco 6500 Series switch, the air from the front intakes  1010  flows through the power supply portion, thereby removing heat generated by the power supply. The air that has been heated by the components is then exhausted, through rear exhaust vent  1015 , as seen in  FIGS. 22 and 24 . 
         [0124]    In addition to or instead of the front to back air flow described above, some electronic equipment  1005  may have a separate air flow that travels from one side of the equipment  1005  to an opposing side of the equipment  1005 . This side to side air flow is generated with the use of fans (not shown) positioned within equipment  1005 . The side to side air flow is utilized to cool various switch connections or other heat generating electronic components positioned within equipment  1005 . The air for this side to side air flow enters equipment  1005  through side intakes  1017 , as shown in  FIG. 24 . The side intakes  1017  are positioned on all opposing side of equipment  1005  from side exhaust vent  1020 , shown in  FIG. 22 . 
         [0125]    An exhaust duct system  1000 , is provided to direct exhaust air coming out of electronic equipment  1005  in a direction toward an area behind the cabinet, which is typically considered a hot aisle. A hot aisle is generally formed when a number of network cabinets are aligned such that the exhaust air flow comes out of the cabinets all on the same side into a single aisle. In this example exhaust duct system  1000  comprises first exhaust duct member  1025 , second exhaust member  1030  and rear exhaust duct member  1035 . These duct members may be constructed of a variety of materials such as sheet metal or plastic and may be constructed as a single component. 
         [0126]    First duct member  1025  is positioned over side exhaust vent  1020  and at least partially encloses the area adjacent to side exhaust vent  1020  such that the air exhausted through side exhaust vent  1020  is directed towards the back of the cabinet. First duct member  1025  is also positioned within the unobstructed space along the side of the cabinet formed between vertical frame rails  105  and  110  and a side panel (not shown), all of which is discussed in more detail hereinabove. Second duct member  1030  has, in the example shown, at least a portion thereof positioned within the unobstructed space described above. Also, in this example, second duct member includes a portion of vertical rail  110  positioned within its interior. However, other embodiments contemplate positioning vertical rail  110  outside of the interior of second duct member  1030 . 
         [0127]    It is understood that duct system  1000  may be secured within cabinet  10  in a number of conventional manners. For example, duct system  1000  may be secured to one or more of equipment rails  20  and/or to one or more vertical members  105 ,  110 . In the example shown, each of the first and second duct members  1025  and  1030  are secured to equipment rail  20  with screws securing tabs  1026  and  1031  which extend from duct members  1025  and  1030  respectively, see  FIGS. 22 and 24 . First and second duct members can be secured to each other in a number of conventional ways. In this example, the inner dimension of second duct member  1030  is slightly larger thin the outer dimension of the first duct member  1025  wherein a portion of the first duct member  1025  snuggly engages an interior portion of second duct member  1030 . Tab  1036  of rear duct member  1035 , with the use of screws, secures duct member  1035  to equipment rail  20  which is positioned on the opposite side of cabinet  10  than equipment rail  20  to which duct members  1025  and  1030  are secured. The other side of rear duct member  1035 , proximate to second duct member  1030 , secures to second duct member  1030  utilizing tabs positioned in rear duct member  1035  engaging slots positioned in second duct member  1030 . 
         [0128]    Second duct member  1030  extends from first duct member  1025  beyond the rear of switch  1005  and toward the rear of the cabinet  10  such that air from side exhaust vent  1020  is directed to the back of cabinet  10  and towards the hot aisle. The structure of first and second duct members  1025  and  1030  connected together, provides a conduit for directing side to side exhaust air  1040  to the rear of cabinet  10 , as seen in  FIG. 24 . Exhaust air  1040  travels through duct members  1025  and  1030  aid exits cabinet  10  through a perforated panel and/or door positioned at the rear of the cabinet adjacent to the open end of second exhaust member  1030 . 
         [0129]    In this example, the cross-sectional area exit openings of side exhaust vent  1020  is less than the cross-sectional area of the first duct member  1025  adjacent to the exit openings of side exhaust vent  1020 . In this example the cross-sectional area of the side exhaust vent  1020  is approximately 230 square inches and the cross-sectional area of first duct member  1025  adjacent to side exhaust vent  1020  is approximately 519 square inches. The increase in cross-sectional area of side exhaust vent  1020  to the cross-sectional area of first duct member  1025  provides for a pressure drop from the interior of electronic equipment  1005  to first duct member  1025 , with the fans in operation This pressure drop results in a more even air flow of the cooling air within equipment  1005  and prevents back pressure from forming at the side exhaust vent  1020 , thereby causing less resistance to the operation of the fan or fans associated with moving the air from side to side within equipment  1005 . 
         [0130]    Exhaust duct member  1035  is positioned to at least partially surround rear exhaust vent  1015 , as seen in  FIGS. 22 and 24 . Duct member  1035  directs the flow of exhaust air  1045  originating from the front to back air flow within equipment  1005  to exit the cabinet through a perforated panel and/or door positioned at the rear of the cabinet adjacent rear exhaust duct member  1035 . In the example shown, rear duct member  1035  is connected to second duct member  1030 . In other examples, rear duct member  1035  may be constructed as a single component with duct members  1025  and/or  1030 . Additionally, rear duct member  1035  may be constructed to be in open communication with adjacent second duct member  1030  or if duct system  1000  is constructed in a single duct component, the rear duct portion may be in open communication with the duct portion adjacent to it.