Patent Abstract:
A retainer includes a device having at least one dovetail-shaped portion, a frame configured to receive the dovetail-shaped portion, and at least one expanding device. The expanding device is configured to compress the dovetail-shaped portion against the frame, thereby securing the device against the frame.

Full Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to retainers and, more particularly, to systems and methods for mounting devices using dovetail grooves and expanders.  
           [0003]    2. Description of Related Art  
           [0004]    Network devices commonly include non-compliant retainers, such as wedge locks, that lock circuit boards or other devices into position. These non-compliant retainers, however, do not allow for mounting of the circuit boards or other devices in a cantilevered state, such that the plane of the circuit board assembly or other device is supported only at one end or edge. Moreover, the network devices are not configured to allow for multiple wedge locks to be implemented in a coplanar fashion.  
           [0005]    Accordingly, there is a need in the art for systems and methods that improve the retention of circuit boards or modules in a network device.  
         SUMMARY OF THE INVENTION  
         [0006]    Systems and methods consistent with the present invention address this and other needs by using an expanding device, such as a wedge lock, to retain a processing module having a dovetail portion within a frame.  
           [0007]    In accordance with the principles of this invention as embodied and broadly described herein, an optical processing device includes a group of processing modules, a frame, and an expanding device. A portion of each of the processing modules is configured in a dovetail shape. The frame is configured to receive the dovetail end of the processing modules. The expanding device is configured to lock the dovetail end of the processing modules to the frame.  
           [0008]    In another implementation consistent with the present invention, a retainer includes a device having a dovetail-shaped portion, a frame configured to receive the dovetail-shaped portion, and at least one expanding device configured to compress the dovetail-shaped portion against the frame.  
           [0009]    In yet another implementation consistent with the present invention, a method for retaining a device, having a dovetail portion, in a frame is provided. The method includes attaching at least one expanding device to the dovetail portion or the frame, sliding the dovetail portion into the frame, and expanding the at least one expanding device to retain the dovetail portion in the frame.  
           [0010]    In a further implementation consistent with the present invention, a method for dissipating heat from a processing module, having a dovetail portion, to a frame is provided. The method includes attaching at least one expanding device to the dovetail portion or the frame, inserting the dovetail portion into the frame, and expanding the at least one expanding device to bring the dovetail portion into contact with the frame and allow for heat dissipation from the processing module to the frame. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate an embodiment of the invention and, together with the description, explain the invention. In the drawings,  
         [0012]    [0012]FIG. 1 illustrates an exemplary system in which systems and methods consistent with the present invention may be implemented;  
         [0013]    [0013]FIG. 2 illustrates an exemplary configuration of the line unit of FIG. 1;  
         [0014]    [0014]FIG. 3 illustrates an exemplary cross sectional view of the processing module/frame interface in an implementation consistent with the present invention;  
         [0015]    [0015]FIG. 4 illustrates an exemplary expanding device in an implementation consistent with the present invention;  
         [0016]    [0016]FIG. 5 illustrates the expanding device of FIG. 4 in an assembled, unexpanded state;  
         [0017]    [0017]FIG. 6 illustrates the expanding device of FIG. 4 in an assembled, expanded state;  
         [0018]    [0018]FIG. 7 illustrates an exemplary configuration of the processing module/frame interface in an alternative implementation consistent with the present invention;  
         [0019]    [0019]FIG. 8 illustrates an exemplary configuration of the dovetail interface in another implementation consistent with the present invention; and  
         [0020]    [0020]FIG. 9 illustrates an exemplary configuration of the processing module/frame interface in a further implementation consistent with the present invention. 
     
    
     DETAILED DESCRIPTION  
       [0021]    The following detailed description of implementations consistent with the present invention refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims and equivalents.  
         [0022]    Implementation s consistent with the present invention provide a dovetail interface for retaining modules within a frame of an underwater device. In an exemplary embodiment, an expanding device is attached to the frame of the underwater device. A dovetail portion of a processing module may be inserted within a receiving portion of the frame. Upon expansion of the expanding device, the dovetail portion is brought into compression with the receiving portion of the frame. Such a configuration enhances the dissipation of heat to the surrounding frame.  
       Exemplary System Configuration  
       [0023]    [0023]FIG. 1 illustrates an exemplary system  100  in which systems and methods consistent with the present invention may be implemented. As illustrated, system  100  includes two land communication portions that are interconnected via an underwater communication portion. The land portions may include land networks  110  and land terminals  120 . The underwater portion may include line units  130  (sometimes referred to as “repeaters”) and an underwater network  140 . Two land networks  110 , land terminals  120 , and line units  130  are illustrated for simplicity. It will be appreciated that a typical system may include more or fewer devices and networks than are illustrated in FIG. 1.  
         [0024]    The land network  110  may include one or more networks, such as the Internet, an intranet, a wide area network (WAN), a local area network (LAN), or another type of network. Land terminals  120  include devices that convert signals received from the land network  110  into optical signals for transmission to the line unit  130 , and vice versa. The land terminals  120  may connect to the land network  110  via wired, wireless, or optical connections. In an implementation consistent with the present invention, the land terminals  120  connect to the line units  130  via an optical connection.  
         [0025]    The land terminals  120  may include, for example, long reach transmitters/receivers that convert signals into an optical format for long haul transmission and convert underwater optical signals back into a format for transmission to the land network  110 . The land terminals  120  may also include wave division multiplexers and optical conditioning units that multiplex and amplify optical signals prior to transmitting these signals to line units  130 , and line current equipment that provides power to the line units  130  and underwater network  140 .  
         [0026]    The underwater network  140  may include groups of line units and/or other devices capable of routing optical signals in an underwater environment. The line units  130  include devices capable of receiving optical signals and transmitting these signals to other line units  130  via the underwater network  140  or to land terminals  120 .  
         [0027]    [0027]FIG. 2 illustrates an exemplary configuration of the line unit  130  of FIG. 1. As illustrated, the line unit  130  may include an outer case  210 , an insulating layer  220 , a frame  230 , groups of processing modules  240 - 246 , and expanding devices  250 . It will be appreciated that a typical line unit  130  may include other devices (not shown) that aid in the reception, processing, or transmission of optical signals.  
         [0028]    The outer case  210  holds the electronic circuits needed for receiving and transmitting optical signals to other line units  130  and land terminals  120 . The outer case  210  provides the electronic circuits with a pressure or watertight environment. As illustrated, the outer case  210  may be of a hollow cylindrical shape. Alternative configurations are also possible.  
         [0029]    The outer case  210  may be fabricated of a high strength material, such as beryllium copper, aluminum, steel, or the like. In an underwater or undersea environment, such a material should be chosen that provides good heat transfer characteristics for dissipating heat from inside the line unit  130  to the surrounding water.  
         [0030]    The insulation layer  220  electrically isolates the electronic circuits and circuit mountings within the line unit  130  from the outer case  210 . The insulator  220  may be applied uniformly to the inside of the outer case  210  to a thickness to withstand expected high voltage within the line unit  130 , but limited from any excessive thickness to maximize heat transfer through the insulator  220 .  
         [0031]    The frame (or chassis)  230  holds the processing modules  240 - 246  in place within the line unit  130 . The frame  230  may also act as a heat sink for the processing modules  240 - 246  and as a heat conduit for the layer of insulation  220 . The frame  230  may be constructed from a high conductivity material, such as aluminum.  
         [0032]    The processing modules  240 - 246  may include electronic circuits for receiving, processing, and transmitting optical signals. The processing modules  240 - 246  may be positioned so that free space exists between adjacent ones of them, allowing them to be free of stress when the line unit  130  is in a high pressure location (e.g., at sea bottom). As will be described in more detail below, one end of each of the processing modules  240 - 246  may have a dovetail configuration that allows the processing module  240 - 246  to be slid into place within the frame  230  in which it is installed.  
         [0033]    The expanding devices  250  lock the processing modules  240 - 246  in place within the frame  230 . With the expanding devices  250  in a relaxed (i.e., non-expanded) state, the processing modules  240 - 246  may slide freely into position within the frame  230 . This allows for a loose fit and generous tolerances in the designs of both the processing modules  240 - 246  and the frame  230 . As the expanding devices  250  are expanded, the interface between the processing modules  240 - 246  and the frame  230  is closed and put into compression. Keeping the processing modules  240 - 246  in intimate contact with the frame  230  assures good thermal conductivity. FIG. 3 illustrates this connection in greater detail.  
         [0034]    As illustrated, a dovetail interface exists between the processing module (e.g., processing module  240 ) and the frame  230 . The optimum angle of the dovetail may depend upon the mass of the processing module  240 , the distance of the center of mass from the base of the sliding dovetail, the direction of any external loads, such as gravity, shock impulses, vibration, centripetal forces, and the like, the width of the sliding dovetail, the desired compression at the interface of the processing module  240  with the frame  230 , and the load producing capability of the expanding device  250 . In an implementation consistent with the present invention, the dovetail angles may be between 30 and 75 degrees. Generally, steeper dovetail angles allow for a wider interface between the processing module  240  and the frame  230 , and the shallower the angle, the greater the compression force generated at the dovetail interface by the expanding device  250 .  
         [0035]    [0035]FIG. 4 illustrates an exemplary expanding device  400  in an implementation consistent with the present invention. It will be appreciated that other expanding devices may alternatively be used. As illustrated, the expanding device  400  includes a rail  410 , a group of wedge lock segments  420 - 428 , washers  440 , and a fastener  450 .  
         [0036]    The rail  410  allows for mounting of the wedge lock segments  420 - 428 . The length and composition of the rail  410  may be selected so as to ensure that the expanding device  400  is capable of locking a processing module  240 - 246  into position within the frame  230 . In one implementation consistent with the present invention, the length of the rail  410  may be approximately equal to the length of the line unit  130 . The rail  410  may be configured to have a “T” bar-like cross-section along its length. Such a configuration allows the rail  410  to retain the wedge lock segments  420 - 428  once the wedge lock segments  420 - 428  are in place. Other configurations may alternatively be used. The rail  410  may be securely mounted to the frame  230  via screws, adhesives, rivets, or the like.  
         [0037]    The wedge lock segments  420 - 428  may be of such a configuration as to allow the wedge lock segments  420 - 428  to slide onto and mate with the rail  410  in such a way that precludes the wedge segments  420 - 428  from becoming easily misaligned. In other words, the wedge segments  420 - 428  should not be able to rotate about the rail  410 , or be removed from the rail  410  except by sliding them off an end of the rail  410 . The wedge lock segments  420 - 428  may include ramped ends that allow the overall height of the expanding device  400  to be adjusted once the segments  420 - 428  are positioned on the rail  410 . The number of wedge segments, and the length of each wedge segment, may be varied in accordance with the type or size of expanding device desired. The wedge lock segments  420 - 428  may be composed of aluminum or other similar types of heat conductive materials.  
         [0038]    The washers  440  may include any conventional type of washers. The fastener  450  may be a screw or another type of fastening device capable of applying pressure to the wedge lock segments  420 - 428  in order to compress the various wedge segments  420 - 428  together and expand the expanding device  400  to the desired height.  
         [0039]    The expanding device  400  may be assembled in the following manner. The rail  410  may be attached to the frame  230  or another appropriate surface, such as the processing module  240 . As illustrated, the rail  410  may include a group of attachment holes  415  that allow the rail  410  to be mounted to the frame  230  via screws, rivets, and the like. Alternatively, the rail  410  may be mounted to the frame  230  through the use of adhesives.  
         [0040]    The end wedge segment  420  may be attached to the rail  410  via an attachment pin  430  or other similar type of mechanism. The end wedge segment  420  serves to retain the other wedge segments  422 - 428  on the rail  410 . The end wedge segment  420  may be attached to the rail  410  prior to or after the rail  410  has been mounted to the frame  230 .  
         [0041]    Once the end wedge segment  420  has been attached to the rail  410 , the other wedge segments  422 - 426  and end wedge segment  428  may be slid onto the rail  410 . As illustrated, the end wedge segment  428  may be configured with an unramped front end that allows the fastener  450  to apply pressure equally through the washers  440  to the wedge lock segments  420 - 428 . The washers  440  and fastener  450  should be locked in place so as to prohibit loosening during use. This may be accomplished, for example, through the use of a mechanical locking device or a thread-locking adhesive.  
         [0042]    Once the wedge segments  420 - 428  have been slid onto the rail  410 , the fastener  450  may connect to the rail  410  via the wedge lock attachment opening  460  in a well-known manner. FIG. 5 illustrates the expanding device  400  of FIG. 4 in an assembled, unexpanded state. As illustrated, when the expanding device  400  is in an unexpanded state, a gap may exist between the expanding device  400  and the processing module  240 . By tightening the fastener  450 , the expanding device  400  expands to fill the gap, as illustrated in FIG. 6. In such a position, the expanding device  400  causes the dovetail interface of the processing module  240  to come in contact with the frame  230  thereby improving thermal dissipation.  
         [0043]    [0043]FIG. 7 illustrates an exemplary configuration of the processing module/frame interface  700  in an alternative implementation consistent with the present invention. As illustrated, gap-filling thermal material  710  is positioned between the dovetail end of the processing module  240  and the frame  230 . The thermal material  710  may include any type of material (e.g., a mica-filled epoxy) that facilitates heat transfer from the processing module  240  to the frame  230 . The thermal material  710  may be applied uniformly to the frame  230  at a thickness to maximize heat transfer through the thermal material  710  to the frame  230 . While shown to fill only part of the gap between the processing module  240  and frame  230 , the thermal material  710  may fill a larger or smaller part of the gap. With the thermal material  710  in place, the transfer of heat from the processing module  240  to the frame  230  is improved.  
         [0044]    [0044]FIG. 8 illustrates an exemplary configuration of the dovetail interface  800  in another implementation consistent with the present invention. Depending upon the length of the processing modules  240 - 246 , two or more expanding devices may be used to lock the processing modules  240 - 246  in place within the frame  230 . For simplicity, two expanding devices  810  and  820  are illustrated in FIG. 8.  
         [0045]    The expanding devices  810  and  820  may be configured in a manner similar to the expanding device described above with respect to FIGS.  4 - 6 . For ease of access, expanding devices  810  and  820  may be accessible via different ends of the processing module  240 . For smaller processing modules, two or more expanding devices may be desirable to increase the compressive load, thereby supporting greater loads and enhancing thermal performance.  
         [0046]    [0046]FIG. 9 illustrates an exemplary configuration of the processing module/frame interface  900  in a further implementation consistent with the present invention. As illustrated, the processing module  240  may include dissimilar dovetail interfaces  910  and  920 . Dovetail angles may be selected so as to optimize thermal and/or structural performance. As described above, an optimum dovetail angle may be selected based on a variety of factors, such as the mass of the processing module  240 , the distance of the center of mass from the base of the sliding dovetail, the direction of any external loads, such as gravity, shock impulses, vibration, centripetal forces, and the like, the width of the sliding dovetail, the desired compression at the interface of the processing module  240  with the frame  230 , and the load producing capability of the expanding device  250 .  
       Conclusion  
       [0047]    Systems and methods, consistent with the present invention, improve retention of and heat dissipation from processing modules in an underwater device. A dovetail portion of a processing modules is forced into compression with a receiving portion of a frame through the use of an expanding device. As a result, heat transfer to the frame is enhanced.  
         [0048]    The foregoing description of exemplary embodiments of the present invention provides illustration and description, but is not intended to be exhaustive or to limit the invention to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of the invention. For example, while the above description focused on an underwater environment, implementations consistent with the present invention are not so limited. For example, the dovetail interface could alternatively be implemented in other environments, such as ground-based, space, or aerospace environments.  
         [0049]    No element, act, or instruction used in the description of the present application should be construed as critical or essential to the invention unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items. Where only one item is intended, the term “one” or similar language is used.  
         [0050]    The scope of the invention is defined by the claims and their equivalents.

Technology Classification (CPC): 5