Abstract:
A case ( 1 ) for housing at least one unit of electronic equipment ( 2 ) includes at least one fan ( 3 ) and an opening ( 15 ) for extracting the fan ( 3 ). A moving element ( 18, 28, 4, 33 ) is provided which, when the fan ( 3 ) is inside the case ( 1 ), is maintained in contact with at least one side of the fan ( 3 ). When the fan ( 3 ) is not inside the case ( 1 ), the moving element is maintained in contact with the case ( 1 ) so as to obstruct the opening ( 15 ) of the case ( 1 ) through which the fan is extracted.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The field of the invention is the fan-cooling of electronic equipment. The invention relates more specifically to a case for containing electronic equipment that needs to be cooled. 
     2. Description of Related Art 
     In the prior art, such a case contains two openings, with a fan close to a first opening aspirating the air contained in the case so as to propel it to the outside through the first opening. The resulting low pressure inside the case creates a draft through the second opening which, by flowing over the electronic equipment, cools it. 
     To avoid having to shut down the equipment when the fan fails, the case is equipped with several fans. Thus, when one fan fails, the cooling continues to be provided by one or more other fans operating as a backup. 
     To replace the failed fan, it is extracted from the case through an opening provided especially for this purpose. Another fan is then inserted into the case through this same opening. 
     In the absence of a fan inside the case, the insertion-extraction opening creates a draft in the case toward the other fan which, by reducing the low pressure inside the case, is detrimental to the proper cooling of the electronic equipment, and possibly to the operational state of the backup fan. 
     It is of course possible to place a cover over the insertion-extraction opening while waiting to install another fan. However, the problem of the draft between the moment in which the fan is extracted and the moment in which the cover is put in place, and between the moment in which the cover is removed and the moment in which the other fan is inserted, still exists. 
     SUMMARY OF THE INVENTION 
     In order to eliminate the drawbacks of the prior art mentioned above, the subject of the invention is a case comprising at least one unit of electronic equipment and an opening for extracting a first fan. The case comprises a moving element which: 
     when the fan is inside the case, is maintained in contact with at least one side of the fan and, 
     when the fan is not inside the case, is maintained in contact with the case so as to obstruct the opening of the case. 
     Thus, as soon as the fan has left the case, the plate immediately obstructs the insertion opening without any additional external manipulation. No discontinuity in the cooling of the electronic equipment is observed. 
     It is possible to use, as the moving element, a plate maintained in position so as to obstruct the opening, for example by means of a spring. By shifting said plate, it is possible to clear the opening so as to allow the fan to be extracted, said plate being held against the fan during the extraction by an increase in the stress on the spring. In this way, the plate directly closes the opening as soon as the fan has completely left the case. 
     However, the device mentioned in the preceding paragraph requires a manipulation prior to the extraction of the fan, i.e., that of shifting the plate. An additional advantage is provided by the invention when said moving element is maintained by the presence of the fan inside the case in a position that leaves the opening clear for extracting the fan, which eliminates the prior operation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     A particular embodiment of the invention is explained in the following description in reference to the figures, in which: 
     FIGS. 1 a,    1   b,    1   c  show a case lacking the characteristics of the invention, 
     FIGS. 2 a,    2   b,    2   c  show a first exemplary case according to the invention, 
     FIGS. 3 a,    3   b,    3   c  show a second exemplary case according to the invention, 
     FIGS. 4 a,    4   b,    4   c  show a third exemplary case according to the invention, 
     FIGS. 5 a,    5   b,    5   c  show a fourth exemplary case according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1 a,  a case  1  comprises electronic equipment  2  and two fans  3 ,  4 . The fans  3 ,  4  are provided for propelling an air flow  5  through a first opening on one side  6  of the case. The air flow  5  is aspirated from the inside of the case  1  to the outside. The low pressure thus produced in the case  1  causes an air flow  8  to enter through a second opening on a side  9  opposite the side  6 . The case  1  is airtight enough for the flow  8  to be equal to the flow  5 . 
     This device ensures air circulation in the case  1  from the side  9  to the side  6 , along the electronic equipment  2 . This air circulation makes it possible to cool the electronic equipment  2 . The side  9  is not necessarily the side opposite the side  6 . In the event that the side  9  is a lateral side of the case  1 , the second opening is disposed so as to ensure enough air circulation along the electronic equipment  2 , in accordance with the prior art. The teaching described herein for fans that aspirate the air from the case  1  also holds true for fans that aspirate external air in order to compress it inside the case. In this case, the high pressure thus created inside the case  1  propels the air toward the outside through the second opening on the side  9 . The high pressure solution increases the turbulence of the air flow inside the case  1 . Increased turbulence promotes heat exchange, but compression increases the temperature of the circulating air. One skilled in the art would choose the most appropriate solution by calculating the optimal exchange coefficients. 
     When a fan fails, for example the fan  3 , the flow  5 ,  8  is weakened. As illustrated in FIG. 1 b,  the fan  3  is removed through an opening  15 , so that it can be replaced. The fan  4  operates as a backup in order to extract an air flow  10  from the case  3 , preferably equivalent to the flow  5 . During the extraction of the fan  3 , the opening  15  remains practically obstructed by the fan, and the flow  10  is approximately equal to a flow  11  entering through the side  9 . As long as the fan  3  is not completely removed, the fan  4  continues to cool the electronic equipment  2 . 
     When the fan  3  is completely removed as illustrated in FIG. 1 c,  the opening  15  allows an air flow  13  to enter the case at low pressure. The flow  13  has the effect of considerably reducing the flow entering through the side  9 , leaving only a weak flow  14  whose circulation along the electronic equipment  2  no longer provides optimal cooling. The flow  12  aspirated by the fan  4  is equal to the sum of the flows  13  and  14 . After the extraction of the fan  3 , it is possible to obstruct the opening  15  with a plate  16  or with a new fan  3 . However, the time interval that separates the end of the extraction of the fan  3  from the placement of the plate  16  or the new fan, is detrimental to the proper cooling of the electronic equipment  2 . 
     Referring to FIGS. 2 a  through  2   c,  magnets  17  are attached to the side of the fan  3  opposite the opening  15 . Magnets  21  are attached to an interior side of the case  1  on the periphery of the opening  15 . 
     Referring to FIG. 2 a,  the magnets  17  magnetically hold a plate  18 , whose area is larger than the area of the opening  15 . The cooling of the device of FIG. 2 a  is identical to that provided by the device of FIG. 1 a.    
     Referring to FIG. 2 b,  the extraction of the fan  3  through the opening  15  carries along the plate  18  held in contact with the side of the fan  3  to which the magnets  17  are attached. This side being the one furthest from the opening  15  for the part of the fan  3  still inside the case  1 , the plate is moved toward the opening  15  during the extraction of the fan  3 . As long as the side to which the magnets  17  are attached is inside the case  1 , the fan  3  obstructs the opening  15 . The cooling of the electronic equipment  2  is identical to that which results from FIG. 1 b.    
     Referring to FIG. 2 c,  when the side of the fan  3  to which the magnets  17  are attached leaves the case  1 , the plate  18 , whose area is larger than that of the opening  15 , is held in place by the case  1  at the level of this opening. The plate  18  is then maintained in contact with the case  1  by the magnets  21  attached to it. Thus, the plate  18  obstructs the opening  15  as soon as the fan  3  has left the case  1 . The outgoing air flow  10  is equal to the incoming air flow  11  in the absence of the fan  3  inside the case  1 , at all times. 
     The insertion of a fan  3  into the case  1  is performed by a reverse process that moves backward through FIGS. 2 c  to  2   a.  The plate  18  is therefore initially maintained in contact with the case by the magnets  21 , as shown in FIG. 2 c.  The insertion of the fan  3  pushes the plate  18 , which separates from the magnets  21 , as shown in FIG. 2 b.  The plate  18  is maintained in contact with the fan  3  by means of the magnets  17 . The insertion of the fan  3  obstructs the opening  15  so that the value of the flows  10  and  11  remains substantially constant. The fan  3  being fully inserted into the case  1  as shown in FIG. 2 a,  the plate  18  is maintained in contact with the fan  3 . 
     Because of the device represented in FIGS. 2 a  through  2   c,  the proper cooling of the electronic equipment  2  is not subject to any interruption during the extraction or insertion of the fan  3  through the opening  15  in the case  1 . 
     Referring to FIGS. 3 a  through  3   c,  a first end of a spring  23  is attached to an interior surface of the case  1  on one edge of the opening  15 . A first edge of a plate  28  is attached to a second end of the spring  23 . The spring  23  is compressed in rotation. 
     Referring to FIG. 3 a,  the fan  3  presses on the plate  28  so as to maximally compress the spring  23 . The compression of the spring  23  maintains the plate  28  in contact with an edge  26  common to the bottom side of the fan  3  and to the vertical side of the fan  3  closest to the spring  23 . The bottom side of the fan  3  in this case is the side furthest from the opening  15 . The cooling by the device of FIG. 3 a  is identical to that provided by the device of FIG. 1 a.    
     Referring to FIG. 3 b,  during the extraction of the fan  3  through the opening  15 , the plate  28  is maintained in contact with the edge  26  of the bottom side of the fan  3  by the compression of the spring  23 . This side being the one furthest from the opening  15  for the part of the fan  3  still inside the case  1 , the extraction of the fan  3  decompresses the spring  23 , which has the effect of rotating the plate  28  so as to move it toward the opening  15 . As long as the bottom side is inside the case  1 , the fan  3  obstructs the opening  15 . The cooling of the electronic equipment  2  is identical to that which results from FIG. 1 b.    
     Referring to FIG. 3 c,  when the bottom side of the fan leaves the case  1 , the plate  28 , whose area is larger than that of the opening  15 , is held in place by the case  1  at the level of this opening on a stop  27 . The plate  28  is therefore maintained in contact with the case  1  by the spring  23 , which is attached to it so as to still be sufficiently compressed. Thus, the plate  28  obstructs the opening  15  as soon as the fan  3  has left the case  1 . The outgoing air flow  10  is equal to the incoming air flow  11  in the absence of the fan  3  inside the case  1 , at all times. 
     The insertion of a fan  3  into the case  1  is performed by a reverse process that moves backward through FIGS. 3 c  to  3   a.  The plate  28  is therefore initially maintained in contact with the case by a slight compression of the spring  23 , as illustrated in FIG. 3 c.  The insertion of the fan  3  pushes the plate  28 , which is subjected to a rotating movement, as illustrated in FIG. 3 b.  The plate  28  is maintained in contact with the fan  3  by means of the spring  23 , which is more strongly compressed. The insertion of the fan  3  obstructs the opening  15  so that the value of the flows  10  and  11  remains substantially constant. The fan  3  being fully inserted into the case  1  as illustrated in FIG. 3 a,  the plate  28  is maintained in contact with the fan  3 . 
     Because of the device represented in FIGS. 3 a  through  3   c,  the proper cooling of the electronic equipment  2  is not subject to any interruption during the extraction or insertion of the fan  3  through the opening  15  in the case  1 . 
     According to a variant of the device of FIG. 3 c,  it is possible to replace the stop  27  with a magnet of the same type as the magnet  21 , which ensures a complete obstruction of the opening  15  by the plate  28  in the absence of the fan  3 . 
     In the example of FIGS. 1 a  through  3   c,  the fans  3 ,  4  are connected in series. The teaching described also holds true for fans connected in parallel, and for more than two fans. FIGS. 4 a  through  4   c  present one particular example in the case where the fans  3 ,  4  are connected in series. 
     Referring to FIG. 4 a,  the fan  4  closest to the external side  6  is maintained in contact with the fan  3  by means of springs  29  attached to the interior wall of the side  6 . The springs  29  are compressed against a side of the fan  4  adjacent to the side  6 . Two rails  19 ,  20  connected to a power supply not represented, carry a supply voltage for the fans  3 ,  4 . The fan  3  comprises a connector  22  plugged into the rail  20  and a connector  24  plugged into the rail  19 . Likewise, the fan  4  comprises two connectors  25 , each plugged into one rail  19 ,  20 . 
     Referring to FIG. 4 b,  during the extraction of the fan  3  through the opening  15 , the fan  4  is maintained in contact with the fan  3  by the compression of the spring  29 . The connectors  22 ,  24  leave the rails  19 ,  20 . As long as the bottom side of the fan  3  is inside the case  1  the fan  3  obstructs the opening  15 , and the fan  4  is maintained in position. The cooling of the electronic equipment  2  is identical to that which results from FIG. 1 b.    
     Referring to FIG. 4 c,  when the bottom side of the fan  3  leaves the case  1 , the fan  3  no longer holds the fan  4 , pushed by the spring  29 , in place The decompression of the springs  29  moves the fan  4  away from the side  6 . The connectors  25  of the fan  4  slide on the rails  19 ,  20  so as to allow the continuity of its power supply. By taking the place of the fan  3 , the fan  4  obstructs the opening  15  as soon as the fan  3  has left the case  1 . The outgoing air flow  10  is equal to the incoming air flow  11  in the absence of the fan  3  inside the case  1 , at all times. An opening  30  through which the fan  4  was inserted, remains wide open. The opening  30  is not detrimental to the proper cooling of the electronic equipment  2  because the flow  10  aspirated or extracted by the fan  4  is equal to the flow  11 . 
     The insertion of a fan  3  into the case  1  is performed by a reverse process, that moves backward through FIGS. 4 c  to  4   a.  The fan  4  is therefore initially maintained in contact with the inside of the case by a slight compression of the springs  29 , as illustrated in FIG. 4 c.  Advantageously, the springs  29  do not press directly on the fan  4 , but on a plate  31  in contact with the external side of the fan  4 . The plate  31  is provided in order to prevent any bypass along the sides of the fan  4 . The plate  31  projects slightly from the case  1  through the opening  30 . This makes it possible to slide the plate  31  to the right, compressing the springs  29 . It may now be said that a new fan  3  plays the role of a new fan  4 , the old fan  4  having replaced the old fan  3 . The insertion of the fan  3  replaces the fan  4 , as illustrated in FIG. 4 b.  The plate  31  is maintained in contact with the fan  3  by means of the compressed springs  29 . The insertion of the fan  3  obstructs the opening  30  so that the value of the flows  10  and  11  remains substantially constant. The new fan  3  being fully inserted into the case  1  as illustrated in FIG. 4 a,  the plate  31  is maintained in contact with the fan  3 . 
     Because of the device represented in FIGS. 4 a  through  4   c,  the proper cooling of the electronic equipment  2  is not subject to any interruption during the extraction or insertion of the fan  3  through the opening  15 , or respectively through the opening  30 , in the case  1 . 
     The insertion of the new fan  3  into the case plugs its connectors  22 ,  24 , respectively, into the rails  19 ,  20  so as to allow it to be supplied with power. This rail connection device is particularly useful for the device of FIG. 4 because it allows a continuous power supply of the fan  4  during its lateral translational movement inside the case  1 . This connection device is usable in the other figures. It has not been represented because more conventional connection devices are also suitable. 
     Referring to FIGS. 5 a  through  5   c,  a first end of springs  32  is attached to an external surface of the case  1  on one edge of the opening  15 . A first edge of a plate  33  is attached to a second end of the spring  32 . The springs  32  are stretched tight. 
     Referring to FIG. 5 a,  the tension of the spring  32  holds the plate  33  over the fan  3  so as to close the opening  15 . The cooling by the device of FIG. 5 a  is identical to that provided by the device of FIG. 1 a.    
     Referring to FIG. 5 b,  the plate  33  is shifted laterally on the case  1  so as to clear the opening  15  for the extraction of the fan  3 . The movement of the plate  33  causes an overextension of the springs  32 , which tends to return the plate  33  to its initial position over the opening  15 . During the extraction of the fan  3  through the opening  15 , the plate  33  is maintained in contact with a vertical side of the fan  3  by the overextension of the springs  32 . This overextension causes an increase in the stress of the springs  32 , which holds the plate  33  against the fan  3 . As long as the vertical side of the fan  3  is inside the case  1 , the fan  3  obstructs the opening  15 . The cooling of the electronic equipment  2  is identical to that which results from FIG. 1 b.    
     Referring to FIG. 5 c,  when the vertical side of the fan  3  leaves the case  1 , the plate  33  is pushed back over the fan  15  by the spring  32 . Thus, the plate  33  obstructs the opening  15  as soon as the fan  3  has left the case  1 . The outgoing air flow  10  is equal to the incoming air flow  11  in the absence of the fan  3  inside the case, at all times. 
     An insertion of the fan  3  into the case  1  is performed by a reverse process that moves backward through FIGS. 5 c  to  5   a.  The plate  33  is therefore initially held over the opening  15  by a slight extension of the spring  32 , as represented in FIG. 5 c.  The plate  33  is shifted laterally so as to clear the opening  15 . The insertion of the fan  3  maintains the plate  33  in the shifted position, as illustrated in FIG. 5 b.  The plate  33  is maintained in contact with the vertical side of the fan  3  by means of the spring  32 , which remains more tightly stretched. The insertion of the fan  3  obstructs the opening  15  so that the value of the flows  10  and  11  remains substantially constant. The fan  3  being fully inserted into the case  1  as illustrated in FIG. 5 a,  the plate  33  is pushed back over the opening  15  by the spring  32 . 
     Because of the device represented in FIGS. 5 a  through  5   c,  the proper cooling of the electronic equipment  2  is not subject to any interruption during the extraction or insertion of the fan  3  through the opening  15  in the case  1 . While this invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, the preferred embodiments of the invention as set forth herein, are intended to be illustrative, not limiting. Various changes may be made without departing from the true spirit and full scope of the invention as set forth herein and defined in the claims.