Abstract:
A convection-cooled electronic system includes an electronic device and a stand. The electronic device has air intake openings in a lower housing portion and air exhaust openings in an upper housing portion. The stand has air intake openings. The stand has a periphery, a flat base, and a slot extending across the widest portion of the stand. The slot has a shape configured to receive the lower portion of the device housing. Heat emitted by electronic components within the device housing creates airflow by convection, which causes air to be drawn into the stand through the stand air intake openings and communicated into the device air intake openings. The air is heated as it passes through the device housing, and the heated air exits the device housing through the air exhaust openings.

Description:
BACKGROUND 
     Various types of electronic equipment contain electronic components that generate thermal energy, i.e., heat, as an undesired by-product of their operation. Electronic equipment therefore commonly includes thermal management or “cooling” systems for dissipating excess heat that could otherwise impair the components. For example, the housing or enclosure of such equipment may include vents. A fan in the housing causes air to flow into the housing through one vent or set of vents, through the housing, and then out of the housing through another vent or set of vents. The airflow carries excess heat from the interior of the housing to the external environment. 
     In a home or small business office, there may be a need to install a small, i.e., desktop or tabletop, telecommunications device, such as modem, residential gateway, wireless access point, etc. Such telecommunications devices commonly have box-shaped enclosures, with various switches, connector sockets, indicator lights, etc., on the sides of the enclosure. To provide a compact shape that can rest unobtrusively on a desk or table, the enclosure may have a length substantially greater than its thickness, somewhat resembling a book in shape. For various reasons, design constraints may be imposed on the location of vents and other thermal management features in the enclosure. 
     SUMMARY 
     Embodiments of the invention relate to a system and method in which an electronic device is cooled by air convection through a stand on which the device is mounted. In an exemplary embodiment, the electronic device has a device housing and one or more thermal energy-emitting electronic components mounted within the housing between lower and upper portions of the device housing. The lower device housing portion has multiple air intake openings, and the upper device housing portion has multiple air exhaust openings. In the exemplary embodiment, the stand has a housing with a periphery and a substantially flat base. The stand housing also has multiple air intake openings distributed about the periphery that allow air to flow in from the exterior of the stand housing to the interior of the stand housing. The stand housing has a slot located across the periphery. The slot has a shape corresponding to the shape of the lower device housing portion such that the lower device housing portion is configured to fit within the slot. When the lower device housing portion is received in the slot, the device air intake openings extend into the slot. 
     In operation, the heat emitted by the electronic components within the device housing creates airflow by convection. Convection causes air to be drawn into the stand through the stand air intake openings and communicated from the interior of the stand into the device air intake openings that extend into the slot. Heat in the device housing is transferred to the air as the air passes through the device housing, and the heated air exits the device housing through the device air exhaust openings in the upper device housing portion, thus removing heat from the device housing. 
     Other systems, methods, features, and advantages will be or become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the specification, and be protected by the accompanying claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. 
         FIG. 1  is a perspective view of a system in which an electronic device is mounted on a stand, in accordance with an exemplary embodiment of the invention. 
         FIG. 2  is a front elevation view of the system of  FIG. 1 . 
         FIG. 3  is a side elevation view of the system of  FIG. 1 . 
         FIG. 4  is a top plan view of the stand of the system of  FIG. 1 . 
         FIG. 5  is a bottom plan view of the system of  FIG. 1 . 
         FIG. 6  is a top plan view of the system of  FIG. 1 . 
         FIG. 7  is an assembly view of the system, showing the mounting of the electronic device to the stand. 
         FIG. 8  is a perspective view of the bottom of the electronic device. 
         FIG. 9  is a perspective view of the stand mounted on the bottom of the electronic device. 
         FIG. 10  is a perspective view of the stand and cable tray mounted on the bottom of the electronic device. 
         FIG. 11  is a sectional view taken on line  11 - 11  of  FIG. 1 , showing airflow through the system that promotes cooling of electronic components within the electronic device. 
     
    
    
     DETAILED DESCRIPTION 
     As illustrated in, for example,  FIGS. 1-3 , in an illustrative or exemplary embodiment of the invention, a system  10  includes a stand  12  and an electronic device  14 . Electronic device  14  can be, for example, a modem, a residential gateway, a wireless access point, or a hybrid of such devices or similar types of devices. Generally, electronic device  14  is of a type that is placed on a table, desk, shelf or similar flat surface (not shown) and connected by one or more electrical or optical signal cables (not shown) to another electronic device, such as a computer, or to a digital communications network. Although in other embodiments such an electronic device can have other shapes, in the exemplary embodiment electronic device  14  has a box-shaped housing defined by a first side panel  16  ( FIGS. 1 and 2 ), a second side panel  18  ( FIG. 2 ) parallel to first side panel  16 , a front panel  20  ( FIGS. 1-3 ), a rear panel  22  ( FIG. 3 ) parallel to front panel  20  and perpendicular to side panels  16  and  18 , a top panel  24  ( FIGS. 1-3 ), and a bottom panel  26  ( FIGS. 1-3 ) parallel to top panel  24 . The terms “front,” “rear,” “side,” “top” and “bottom” are used only for convenience of description and are not intended to imply any characteristics or other limitations. Front panel  20  can have, for example, indicator lamps  28  or other features. Although not shown for purposes of clarity, rear panel  22  can have connector jacks or other features. 
     In the exemplary embodiment, stand  12  has a generally circular periphery. More specifically, in the exemplary embodiment stand  12  has a frusto-conical shape defined by a generally circular base  30 , a generally circular or disc-shaped top  32  of smaller diameter than base  30 , and a sloping sidewall  34  between base  30  and top  32 . Base  30  defines a plane on which stand  12  can be rested on a table, desk, shelf or other surface (not shown). In other embodiments, such a stand may have other suitable shapes, such as rectangular, square, triangular, etc. 
     As further illustrated in  FIG. 4 , stand  12  has a slot  36  with a substantially rectangular shape. Accordingly, slot  36  has a length (“L_SLOT”) and a width (“W_SLOT”). Slot  36  extends length-wise across the widest part or diameter (“DIA”) of stand  12 . Slot  36  thus also extends across the diameter of top  32 , forming a substantially rectangular opening in top  32  between the exterior and interior of stand  12 . It can also be noted that slot  36  intersects sidewall  34 . In embodiments (not shown) in which the periphery has a shape other than circular, such a slot can extend across the width or widest part of the stand. 
     Sidewall  34  has air intake gratings  38  and  40  on opposing sides of slot  36 . Each of air intake gratings  38  and  40  is defined by closely spaced apertures or openings between the exterior and interior of stand  12 . Each opening has an elongated, substantially rectangular shape, elongated parallel to the surface of sidewall  34 . On each side of slot  36  these closely spaced openings are distributed in sidewall  34  along an arc-shaped region defining a respective one of air intake gratings  38  and  40 . 
     As illustrated in  FIGS. 5 and 8-10 , a device air intake grating  42  is defined by closely spaced, parallel apertures or openings in bottom panel  26  of device  14 , i.e., between the exterior and interior of the housing of device  14 . As illustrated in  FIGS. 6-7 , a device air exhaust grating  44  is similarly defined by closely spaced, parallel apertures or openings in top panel  24  of device  14 , i.e., between the exterior and interior of the housing of device  14 . Note that in the exemplary embodiment side panels  16  and  18  have no openings or other airflow or vent features. 
     The openings that define air intake gratings  38 ,  40  and  42  and air exhaust grating  44  can have a uniform width and rounded ends to promote smooth airflow, i.e., inhibit turbulent airflow. The spacing between adjacent openings can be uniform and substantially equal to or even slightly less than the width of the openings, to promote both airflow and structural integrity. Note that the spacing of the openings that define air intake gratings  38  and  40  is slightly less than the width of the openings, thereby providing a louvered appearance and airflow effect. 
     As illustrated in  FIG. 7 , the lower portion of the housing of device  14 , defined primarily by bottom panel  26 , fits snugly within slot  36 . More specifically, the device housing has a thickness or width (“W_DEV” in  FIG. 2 ) almost or substantially equal to the slot width (“W_SLOT” in  FIG. 4 ) of slot  36 , thereby providing a snug fit, such as an interference fit or frictional fit. As a result of this snug or frictional fit and additional attachment features described below, stand  12  provides a stable base for supporting electronic device  14 . The relative dimensions between stand  12  and device  14  can aid this stabilizing function. In the exemplary embodiment, the device housing length (“L_DEV” in  FIG. 3 ) is greater than the slot length (“L_SLOT” in  FIG. 4 ) of slot  36 . Thus, when device  14  is mounted on stand  12 , device  14  overhangs or extends beyond the ends of slot  36  in this housing length (“L_DEV”) dimension. This feature can promote stability in a forward-rearward direction. In addition, it can be noted that in the exemplary embodiment the device housing height (“H_DEV” in  FIG. 3 ) is approximately twice the device housing length (“L_DEV”), such that the device housing has an elongated rectangular shape. In other embodiments, the device housing can have a still greater height relative to its length, as the configuration can provide a stable support for such “tall” electronic devices. The configuration can promote lateral stability even for relatively tall electronic devices because, among other reasons, the device housing thickness or width (“W_DEV”) is about one-third of the diameter (“DIA” in  FIG. 4 ) of stand  12 . Note that the diameter (“DIA”) of stand  12  relates to the stability or tendency to remain upright of stand  12  when resting on a surface (not shown). Correspondingly, the slot width (“W_SLOT”) of slot  36  is about one-third the diameter (“DIA”) of stand  12 . In other embodiments (not shown), the slot width of such a stand can be between about, for example, one-quarter and one-half the stand diameter. 
     Additional features promote a secure connection between stand  12  and device  14 . These features include two hooked tabs  46  ( FIGS. 4 and 7 ) on stand  12 . To assemble stand  12  to device  14 , hooked tabs  44  are inserted into two corresponding openings  48  ( FIG. 8 ) in bottom panel  26  of device  14 . Then, the lower portion of device  14  is seated within slot  36  to form the assembly shown in  FIG. 9 . Note that when the lower portion of device  14  is seated within slot  36 , device air intake grating  42  extends into slot  36  and thus into the interior of stand  12 . In this position, air can be communicated between the interior of stand  12  and device air intake grating  42 . 
     As illustrated in  FIG. 10 , a cable tray  50  is then inserted inside stand  12 . A screw  52  is then routed through corresponding holes  54  ( FIG. 9 ) in cable tray  50  and stand  12  into a threaded bore  56  ( FIG. 8 ) in bottom panel  26  to secure cable tray  50  and stand  12  to electronic device  14 . Although not shown for purposes of clarity, an optical or electrical cable that is connected to a connector  58  ( FIGS. 8-10 ) of device  14  can be wound inside cable tray  50  for storage. A portion of the cable can exit stand  21  through a guide structure  60  ( FIGS. 5 and 10 ) in cable tray  50 . 
     As illustrated in  FIG. 11 , a number of thermal energy-emitting electronic components  62  are mounted on a printed circuit board (PCB)  64  in electronic device  14 . Standoff structures  66  and  68  capture PCB  64  to help position PCB  64  within the housing of device  14 . In operation, electronic components  62  emit heat, which generates air movement or airflow by convection. As illustrated by the arrows in  FIG. 11 , this airflow enters the interior of stand  12  through air intake gratings  38  and  40 . The airflow continues into the interior of the housing of device  14  through device air intake grating  42  ( FIGS. 5 and 8-10 ). The resulting airflow through the housing and past the heat-emitting electronic components  62  carries the emitted heat away. The airflow exits the housing through device air exhaust grating  44  ( FIGS. 1, 6 and 7 ). The airflow thus removes heat from the interior of the device housing that could otherwise impair electronic components  62  or other features of electronic device  14 . Also, as stand  12  supports bottom panel  26  above the desk, table or other surface (not shown) on which stand  12  rests, the surface is protected against potential damage by heat emanating from bottom panel  26 . 
     One or more illustrative or exemplary embodiments of the invention have been described above. However, it is to be understood that the invention is defined by the appended claims and is not limited to the specific embodiments described.