Abstract:
A connection system for interconnecting communication media comprises a housing including a cavity and an airflow opening, a cover adapted to cooperate with the housing to define an air reservoir, and an airflow agitator for causing air to move from the air reservoir to the housing through the airflow opening. The air reservoir contains at least a portion of the housing including the airflow opening, and the air reservoir and the housing cooperate to prevent fluid from entering the cavity. One method for dissipating heat within a connection system comprises providing a connection system including a housing with an airflow opening and a cover adapted to cooperate with the housing to define an air reservoir containing at least a portion of the housing and the airflow opening. The method further includes forcing air from the air reservoir to the housing through the airflow opening.

Description:
FIELD 
   The present invention relates to a connection system and a method for interconnecting communications media. In particular, the present invention relates to a waterproof underground cabinet for interconnecting communications media having a system for cooling components within the underground cabinet, and the present invention relates to a method for cooling the components within the underground cabinet. 
   BACKGROUND 
   Currently, there is a requirement for communications media, such as fiber optic, copper, coaxial cables, or the like to be interconnected at various locations in order to provide communication services over distributed areas, such as to individuals&#39; houses, or the like. This is typically achieved by providing junction boxes or cabinets to interconnect wires, with the cabinets being located underground in a convenient location. 
   An underground cabinet typically contains electrical connections and optionally other electronic components. The electrical components during operation will heat up and without proper cooling may become damaged. It is important that the contents of the underground cabinet are protected from contaminants such as dust and moisture. Various designs have been developed for protecting the underground cabinet from contaminants. However, such designs often cannot provide for adequate airflow into and out of the underground cabinet to properly cool the electrical components while also protecting the electrical components in the underground cabinet from contaminants. 
   BRIEF SUMMARY 
   A connection system for interconnecting communication media comprises a housing including a cavity and an airflow opening, a cover adapted to cooperate with the housing to define an air reservoir, and an airflow agitator causing air to move from the air reservoir to the housing through the airflow opening. The air reservoir contains at least a portion of the housing including the airflow opening, and the air reservoir and the housing cooperate to prevent fluid from entering the cavity. 
   One method for dissipating heat within a connection system for interconnecting communication media comprises providing a connection system including a housing with an airflow opening and a cover adapted to cooperate with the housing to define an air reservoir containing at least a portion of the housing and the airflow opening. The air reservoir and the housing cooperate to prevent fluid from entering the housing. The method further includes forcing air from the air reservoir to the housing through the airflow opening. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is perspective view of one embodiment of the connection system of the present invention. 
       FIG. 2  is a longitudinal vertical sectional view of the housing and cover of the connection system. 
       FIG. 3  is a longitudinal sectional view of the housing and cover of the connection system, as taken along lines  3 - 3  in  FIG. 2 , with some details removed for clarity of illustration. 
       FIG. 4  is a longitudinal sectional schematic of the lifting mechanism lifting the connection system of the present invention. 
       FIG. 5  is a longitudinal sectional schematic of an embodiment of a connection system of the present invention. 
       FIG. 6  is a longitudinal sectional schematic of another embodiment of a connection system of the present invention. 
   

   While the above-identified figures set forth several embodiments of the invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the spirit and scope of the principals of this invention. The figures may not be drawn to scale. Like reference numbers have been used throughout the figures to denote like parts. 
   DETAILED DESCRIPTION 
     FIG. 1  is perspective view of one embodiment of the connection system of the present invention. A similar connection system is disclosed in PCT Application number PCT/US2004/009986, titled “Connection System,” filed on Apr. 1, 2004, the disclosure of which is hereby incorporated by reference. An underground cabinet  100  includes a housing  110  and a separable cover  130 . The housing  110  has an upper cavity  112 , a lower cavity  114 , sides  113   a  and  113   b , and ends  115   a  and  115   b . A lid  116  covers the otherwise open top of the upper cavity  112 . An upper lip  118  is provided around the perimeter of the upper cavity  112  to allow for the lid  116  to be removably mounted to the upper cavity  112  for access to the contents of the housing  110 . The lid  116  may be attached to the upper lip  118  by a variety of attaching means, such as screws, clips, or the like. The lid  116  may also be sealed to the upper lip  118 . 
   Located on the lid  116  is an airflow-in opening  124  and an airflow-out opening  126 , which provide airflow access into and out of the housing  110  of the underground cabinet  100 . The airflow-in opening  124  and airflow-out opening  126  may each be covered with a filter, which prevents dust and other debris from entering the housing  110 . In one embodiment, the filter can be any suitable 3M™ Filtrete™ Filter, available from 3M Company of St. Paul, Minn., USA. 
   A gasket  128  is provided along the lid  116  and sides  113   a  and  113   b  of the exterior of the housing  110 . In the embodiment shown in  FIG. 1 , the gasket extends entirely along the sides  113   a  and  113   b  of the exterior of the upper cavity  112  to the lower lip  120 . The gasket  128  separates the airflow-in opening  124  from the airflow-out opening  126 . The gasket  128  may be positioned at various locations on the lid  116  and sides  113   a  and  113  (see  FIG. 1 ,  2 ,  5 ). In other embodiments, the gasket  128  may extend along only a portion of the sides  113   a  and  113   b  of the exterior of the housing  110  or along only a portion of the lid  116 . 
   The cover  130  fits over the upper cavity  112  of the housing  110  and has a bottom edge  131 , which rests along two lower lips  120  extending along an exterior edge of the upper cavity  112 . The lower lips  120 , in the embodiment shown in  FIG. 1 , extend on two opposites sides  113   a  and  113   b  of the housing  110  on the upper cavity  112 . The bottom edge  131  of the cover  130  rests on and attaches to the lower lips  120  by any suitable attaching means, such a screws, clips, or the like to secure the cover  130  to the housing  110 . In  FIG. 1 , the underground cabinet  100  is shown with the lower lips  120  extending only along the lengths of the sides  113   a  and  113   b  of the underground cabinet  100 . It is understood that the lower lips  120  may extend along the length of the ends  115   a  and  115   b  of the underground cabinet  100  with the appropriate changes made to the positioning of the gasket  128 , airflow-in opening  124 , and airflow-out opening  126 . 
     FIG. 2  is a longitudinal vertical sectional view of the assembled underground cabinet  100  shown in  FIG. 1 . The cover  130  is resting and attached to the lower lips  120 . (See  FIGS. 1 and 2 ). However, the lower lips  120  are not located on all four sides of the housing  110  such that when the cover is in place over the housing  110 , end openings  132   a  and  132   b  are formed between the cover  130  and housing  110  on the ends  115   a  and  115   b  of the housing  110  where the lower lips  120  are missing. 
     FIG. 3  is a longitudinal sectional view of the assembled underground cabinet  100  shown in  FIG. 1 , taken horizontally through the cover  130  and upper cavity  112 . As can be seen, the cover  130  is larger than the upper cavity  112 . The bottom edge  131  of the cover  130  contacts and attaches to the lower lip  120  but extends beyond the ends  115   a  and  115   b  of the upper cavity  112  not having the lower lip  120  to form the end openings  132   a  and  132   b . The end openings  132   a  and  132   b  allow for airflow access into the gap created between an outer wall of the housing  110  and inner wall of the cover  130 , which creates an air reservoir  140  there between (see  FIG. 2 ). While only end opening  132   a  and  132   b  are illustrated, the end openings  132   a  and  132   b  could be located anywhere about the periphery of the housing  110  to allow access to the gap between the housing  110  and the cover  130 . 
     FIG. 4  is a longitudinal sectional schematic of the lifting mechanism for the connection system of the present invention with the cover  130  removed. In use, the underground cabinet  100  is adapted to be placed in a pit  150  in the ground G, to allow underground cables  159  to be connected to each other. The housing  110  is shown as positioned in a pit  150  lifted by a lifting mechanism  160 . The lid  116  is shown in an open position, which allows access to the contents of the cavities  112  and  114 . The pit  150  includes a base  152  and sidewalls  154  with the top of the pit  150  open. A surface lid  156 , as shown in  FIGS. 5 and 6 , is provided to rest on a rim lip  158  of the pit  150  (the surface lid  156  is removed in  FIG. 4 ). The pit  150  may be formed of any suitable material, such as concrete, and may be precast or built on site. Cables  159  enter the pit  150  for connection to the underground cabinet  100 . 
   The pit  150  includes a lifting mechanism  160  for lifting the underground cabinet  100 . The lifting mechanism  160  is coupled to one side wall  154  and is described in PCT application number PCT/US2004/009986, titled “Connection System,” filed on Apr. 1, 2004, which is hereby incorporated by reference. 
   Tines  164  extend outwardly from the lifting mechanism  160 , parallel to the base  152  of the pit  150 . The tines  164  engage a lower side of the upper cavity  112 , and can be moved by manipulation of the lifting mechanism  160  to raise and lower the housing  110  relative to the pit  150 . 
   In one embodiment, a withstand leg  166  is provided opposite from the lifting mechanism  160  to support the tines  164 . Located along the sidewall  154  of the pit  150  is a channel  167 , within which the withstand leg  166  travels vertically. The withstand leg  166  includes a vertical section  168  and a horizontal section  169 . The vertical section  168  is attached to the end of the tines  164  opposite the lifting mechanism  160 . The horizontal section  169  extends from a lower portion of the vertical section  168  and connects to the channel  167 . Within the channel  167  is a stop mechanism. The stop mechanism allows for the withstand leg  166  to travel up the channel  167  but prevents the withstand leg  166  from traveling down the channel unless the stop mechanism is disengaged. The stop mechanism can be a stop bar placed in the channel  167 , a release pin mechanism placed within or adjacent the channel  167  or other type of device which supports the withstand leg  166  and tines  164 . In use, when the lifting mechanism  160  raises or lowers the tines  164 , the withstand leg  166  passes along the channel  167  and rests on the stop mechanism to support for the end of the tines  164  opposite the lifting mechanism  160 . 
   The lifting mechanism was described with respect to underground cabinet  100 , but it is understood that the lifting mechanism may be used with underground cabinet  200  as shown in  FIG. 6  or other such underground cabinets within the scope of the present invention. 
     FIG. 5  is a longitudinal sectional schematic of an embodiment of a connection system of the present invention. In use, the underground cabinet  100  allows underground cables  159  to be connected to each other. The cables  159  enter the pit  150  and are inserted into aperture  122 , which is then sealed to prevent water, dust, and airflow into or out of the cavities  112  and  114 . The aperture  122  may be sealed using any number of sealing techniques and products such as Cold Shrink Tubing (CST), available from 3M Company of St. Paul, Minn., USA, which is an open ended tubular rubber sleeve of high stretch rubber that has been factory expanded and assembled onto a removable hollow core. CST Tubing may be formed from rubber, silicon rubber, or the like and can be coupled to the aperture  122  and then extended over the cables  159 , as will be appreciated by persons skilled in the art. Alternatively, a seal between the aperture  122  and the cables  159  can be achieved using mastic rubber, self bonding sealing tape, adhesive lined heat shrink PVC tubing, or the like. 
   The presence of the lid  116  and filters covering the airflow-in opening  124  and airflow-out opening  126  prevent dust and other debris from entering the cavities  112  and  114 . However, the airflow-in opening  124  and airflow-out opening  126  do not prevent moisture from entering the cavities  112  and  114 . In some applications, it is desirable that cabinets, in particular underground cabinets, be capable of providing protection for the internal components at a standard of IP68 (according to (AS 1939-1990)-IEC529-1989 degrees of protection provided by enclosures for electrical equipment (IP code)). IP6X represents total protection against dust, and IPX8 represents total protection against submersion, such that IP68 is total protection against dust and submersion. 
   The cover  130  placed over the housing  110  provides the additional level of protection against submersion. The positioning of the cover  130  over the housing  110  forms an air reservoir  140 . In the event the underground cabinet  100  is immersed in water, the rising water level will cause air to be trapped in the air reservoir  140  (which includes air trapped between the cover  130  and housing  110 , as well as the air within the cavities  112  and  114 ). The air pressure in the air reservoir  140  prevents water from rising up the sides  113   a  and  113   b  (see  FIG. 1 ) and ends  115   a  and  115   b  of the housing  110  to the upper lip  118 , thereby preventing water from entering the cavities  112  and  114 . 
   Electrical components  170  located within the underground cabinet  100  produce heat when operating. Typically, it is desirable to maintain the temperature within the housing  110  at less than 50 degrees Celsius under the transmission power 200 Watts. Therefore, to properly maintain the temperature within the housing  110 , a heat dissipation system  180  is included to move cooler air from within the pit  150  to within the housing  110 . 
   The heat dissipation system  180  includes an airflow agitator  182 , a temperature sensor  184 , and a power supply  190 . The airflow agitator  182  may be a DC fan, an AC fan, or other type of device for causing airflow movement. The airflow agitator  182  is located within the housing  110  and arranged to move air from the first air reservoir  142 , into the housing  110 , and then out of the housing to the second air reservoir  144 . As shown in  FIG. 5 , the airflow agitator  182  is positioned to pull air from the first air reservoir  142 . However, the airflow agitator  182  may be positioned to push air from the housing  110  into the second air reservoir  144 . Further, the housing may have a separate compartment, which is in communication with the airflow-in opening  124 , where the fan is located to pull air from the compartment and force air into the remaining portion of the housing  110  where the electrical components  170  are located. The airflow agitator  182  may be positioned within the air reservoir  140  to either push air into the housing  110  or pull air from the housing  110 . 
   The temperature sensor  184  senses the current temperature within the housing  110 , and when the temperature within the housing  110  reaches a threshold level, the airflow agitator  182  is activated to cool the housing  110 . When the air within the housing  110  has cooled to below the threshold level, the airflow agitator  182  is deactivated and is no longer supplied power to operate. 
   The power source  190  provides a source of power to operate the airflow agitator  182 . The power source  190  may be a battery, such as a Ni—Cd battery located within the housing  110 , or some other suitable power source. 
   When the airflow agitator  182  is activated, air from within the pit  150  is pulled into an opening  132   a  to the first air reservoir  142 . The arrows A in  FIG. 5  are representative of the airflow. Typically, the air in the pit  150  is cooler than the air within the housing  110  because the electrical components  170  within the housing  110  heat up the air within the housing  110 . The airflow agitator  182  pulls the air from the first air reservoir  142  through the airflow-in opening  124  and into the housing  110 . The airflow agitator  182  is designed such that cool air pulled in from the first air reservoir  142  passes across the electrical components  170  to cool the air within the housing  110  by convection. Once the air passes across the electrical components  170 , the air then exits the housing  110  through the airflow-out opening  126 . From the airflow-out opening  126 , the warmer air enters the second air reservoir  144  and enters the pit  150 . When filters cover the airflow-in opening  124  and the airflow-out opening, dust and debris are prevented from entering the housing  110 . 
   The gasket  128  provides an airflow seal between the upper cavity  112  and the cover  130  to effectively separate the cooler air in the first air reservoir  142  going into the housing from the warmer air in the second air reservoir  144  exiting the housing. When the cover  130  is in place on the housing  110 , the gasket  128  engages the opposed walls of the cover  130  and housing  110  in a sealed relation, thereby separating the reservoirs  142  and  144 . 
   Although not shown, when the underground cabinet  100  is submerged in water, water may cover the end openings  132   a  and  132   b  into the first air reservoir  142  and out of the second air reservoir  144 . However, because of the air pressure from the air trapped in the cover  130  and housing  110 , the water does not reach a level high enough to enter the housing  110 . When the end openings  132   a  and  132   b  are covered with water, the airflow agitator  182  would not pull in cool air from the pit  150  because the end openings  132  are blocked. However, typically when water is surrounding the underground cabinet  100 , the water effectively cools the underground cabinet  100  to appropriate levels by conduction. 
   It is understood that although the description of the movement of the airflow was with respect to the airflow agitator  182  positioned such that it is pulling cool air from the first air reservoir  142 , the airflow agitator  182  may be positioned such that it is pushing warm air from the housing  110  into the second air reservoir  144 . 
     FIG. 6  is a side view of another embodiment of a connection system of the present invention. A similar connection system is disclose in PCT Application number PCT/US2004/009986, titled “Connection System,” filed on Apr. 1, 2004, the disclosure of which is hereby incorporated by reference. An underground cabinet  200  is shown as positioned in the pit  250  in the ground G. In this embodiment the underground cabinet  200  includes a housing  210  and a separable cover  230  positioned over the housing  210 . The housing includes an upper cavity  212 , a lower cavity  214 , sides, and ends  215   a  and  215   b  (similar to the underground cabinet shown in  FIG. 1 ). Extending around the upper perimeter of the upper cavity  212  is an upper lip  218 , to which a lid  216  may be removably attached by a variety of attaching means, such as screws, clips, or the like. The lid  216  may also be sealed to the upper lip  218 . 
   Located on the lid  216  is an airflow opening  224 , which provides airflow access into and out of the housing  210  of the underground cabinet  200 . The airflow opening  224  may be covered with a filter, which prevents dust and other debris from entering the housing  210 . In one embodiment, the filter can be any suitable 3M™ Filtrete™ Filter, available from 3M Company of St. Paul, Minn., USA. 
   The cover  230  fits over the upper cavity  212  of the housing  210  and has a bottom edge, which rests along two lower lips extending along an exterior edge of the upper cavity  212  as with cabinet  100  shown in  FIGS. 1-2 . The lower lips, similar to the lower lips  120  as shown in the embodiment in  FIG. 1 , extend on two opposites sides of the housing  210  on the upper cavity  212 . The bottom edge of the cover  230  rests on and attaches to the lower lips by any suitable attaching means, such a screws, clips, or the like to secure the cover  230  to the housing  210 . The underground cabinet  200  has lower lips extending only along the lengths of the sides of the underground cabinet  200 . It is understood that the lower lips may extend along the lengths of the ends  215   a  and  215   b  of the underground cabinet  200 . 
   The bottom edge of the cover  230  rests and attaches to the lower lips. However, the lower lips are not located on all four sides of the housing  210  such that when the cover  230  is in place over the housing  210 , end openings  232  are formed between the cover  230  and the housing  210  on the ends  115   a  and  115   b  of the housing  210 , where the lower lips are missing. The end openings  232  allow for airflow access into the gap created between an outer wall of the housing  210  and the inner wall of the cover  230 , which creates an air reservoir  240  there between. 
   The cover  230  placed over the housing  210  provides the additional level of protection against submersion. In this embodiment, no gasket is provided between the cover  230  and the housing  210 . Therefore, the positioning of the cover  230  over the housing  210  forms a single air reservoir  240 . In the event the underground cabinet  200  is immersed in water, the rising water level will cause air to be trapped in the air reservoir  240  (which includes air trapped between the cover  230  and housing  210 , as well as the air within the cavities  212  and  214 ). The air pressure in the air reservoir  240  prevents water from rising up the sides and ends  215   a  and  215   b  of the housing  210  to the upper lip  218 , thereby preventing water from entering the cavities  212  and  214 . 
   As with the embodiment described with respect to  FIGS. 1-5 , within the underground cabinet  200  are electrical components  270  which, when operational, create heat. Therefore, to properly maintain the temperature within the housing  210 , a heat dissipation system  280  is included to move cooler air from outside of the underground cabinet  200  to within the housing  210 . 
   The heat dissipation system  280  includes an airflow agitator  282 , a temperature sensor  284 , and a power supply  290 . The airflow agitator  282  may be a DC fan, an AC fan, or other type of device for causing airflow movement. The airflow agitator  282  is located within the housing  210  and arranged to move air from the air reservoir  240  into the housing  210 , and then out of the housing  210  through the airflow opening  224 . The airflow agitator  282  may be located within the air reservoir  240  and arranged to move air from the air reservoir  240  into and out of the housing  210 . 
   The temperature sensor  284  senses the current temperature within the housing  210 , and when the temperature within the housing  210  reaches a threshold level the airflow agitator  282  is activated. The power source  290  provides a source of power to operate the airflow agitator  282 . The power source  290  may be a battery, such as a Ni—Cd battery located within the housing  210 , or some other suitable power source. 
   When the airflow agitator  282  is activated, air within the housing  210  is agitated such that some of the air exits the housing  210  and some air enters the housing  210  through the airflow opening  224 . The arrows A in  FIG. 6  illustrate the desired airflow patterns. The air that enters the housing  210  from the air reservoir  240  and the pit  250  is cooler than the air within the housing  210  because the electrical components  270  within the housing  210  heat up the air within the housing  210 . The airflow agitator  282  ultimately pushes air from the housing  210  to the air reservoir  240  resulting in some air from the air reservoir  240  entering the housing  210 . The airflow agitator  282  is designed such that cool air from the air reservoir  240  enters the housing  210  and passes across the electrical components  270  to cool the air within the housing  210  by convection. Once the air passes across the electrical components  270 , some of the air then exits the housing  210  through the airflow opening  224 . From the airflow opening  224 , the warmer air enters the air reservoir  240  and enters the pit  250 . 
   Although not shown, when the underground cabinet  200  is submerged in water, water may cover the openings  232  into and out of the air reservoir  240 . In such a case, the airflow agitator  282  would only circulate air within the housing  210  and air reservoir  240 , and the airflow agitator  282  would not pull in cool air from the pit  250  because the openings  232  are blocked. However, typically when water is surrounding the underground cabinet  200 , the water effectively cools the underground cabinet  200  to appropriate levels by conduction. 
   Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.