Abstract:
An apparatus including a heat sink compatible with a rail, the heat sink including two engagement windows that align with a corresponding pair of rail engagement windows when the apparatus is positioned in the rail. A handle engaged with the heat sink, the handle to enable a retention position and a retraction position of the apparatus. A first latch and a second latch laterally opposed and positioned within a first cavity and a second cavity, respectively, of the heat sink. A first spring and a second spring laterally opposed and positioned within the first and second cavities, respectively, of the heat sink, the first and second springs engaged with the handle and the first and second latches, wherein the first and second springs to push a first latch end of each latch into the rail engagement window when the apparatus is in a retention position, wherein the first and second springs to actuate the retraction of the first latch end of each latch when the handle is used to place the apparatus in a retraction position.

Description:
BACKGROUND  
       [0001]     1. Field  
         [0002]     Embodiments of the invention relate to the field of latching mechanisms and more specifically, but not exclusively, to an optical device latching mechanism.  
         [0003]     2. Background Information  
         [0004]     Optical networks are used in telecommunication and enterprise networks to move data and communications. Optical signals provide high-speed, superior signal quality, and minimal interference from outside electromagnetic energy. Optical networks utilizing Dense Wavelength Division Multiplexed (DWDM) systems offer tunable multi-channel optical links. Such optical links may operate at line rates up to 10 Gigabits per second (Gb/s).  
         [0005]     Optical networks may use switches to pass signals between optical networks and servers, host systems, and communication devices. A switch may include several optical devices, such as transceivers, to convert between optical signals and electrical signals. In today&#39;s switches, optical devices are often mounted in racks using screws or fasteners.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0006]     Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.  
         [0007]      FIG. 1  is a perspective view of a latching mechanism in accordance with one embodiment of the present invention.  
         [0008]      FIG. 2A  is a perspective view of a latching mechanism in accordance with one embodiment of the present invention.  
         [0009]      FIG. 2B  is an exploded view of a latching mechanism in accordance with one embodiment of the present invention.  
         [0010]      FIG. 3  is an exploded view of a latching mechanism in accordance with one embodiment of the present invention.  
         [0011]      FIG. 4A  is a perspective view of a latching mechanism in accordance with one embodiment of the present invention.  
         [0012]      FIG. 4B  is an exploded view of a latching mechanism in accordance with one embodiment of the present invention.  
         [0013]      FIG. 5  is a block diagram of a latching mechanism in accordance with one embodiment of the present invention.  
         [0014]      FIG. 6A  is a block diagram of a latching mechanism in accordance with one embodiment of the present invention.  
         [0015]      FIG. 6B  is a block diagram of a latching mechanism in accordance with one embodiment of the present invention.  
         [0016]      FIG. 6C  is a block diagram of an angled wall of a heat sink holding a latching mechanism in accordance with one embodiment of the present invention.  
         [0017]      FIG. 7A  is a block diagram of a latching mechanism in accordance with one embodiment of the present invention.  
         [0018]      FIG. 7B  is a block diagram of a latching mechanism in accordance with one embodiment of the present invention.  
         [0019]      FIG. 7C  is a block diagram of a latching mechanism in accordance with one embodiment of the present invention.  
         [0020]      FIG. 8  is a block diagram of a system including a latching mechanism in accordance with one embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0021]     In the following description, numerous specific details are set forth to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that embodiments of the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring understanding of this description.  
         [0022]     Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.  
         [0023]     Embodiments of the present invention are in compliance with the “ X 2  MSA  ( Multi - Source Agreement ):  A Cooperation Agreement for a Small Versatile  10  Gigabit Transceiver Package, ” Feb. 28, 2003, revision 1.0 b (referred to hereafter as the “X2 MSA”). However, it will be understood that embodiments of the invention are not limited to use in X2-compliant transceivers, but may be used in various optical devices.  
         [0024]     Turning to  FIGS. 1-4B , an embodiment of a transceiver  102  having a latching mechanism  103  is shown.  FIG. 1  shows a perspective top view of transceiver  102 .  FIG. 2A  shows a perspective bottom view of transceiver  102 .  FIG. 2B  shows an exploded bottom view of transceiver  102 .  FIG. 3  shows an exploded bottom view of transceiver  102 .  FIG. 4A  shows a perspective view of transceiver  102 .  FIG. 4B  shows an exploded bottom view of transceiver  102 . It will be understood that point of reference terms, such as “top” and “bottom,” are used herein for clarity to the reader and are not intended to limit the placement or mounting of transceiver  102  to any particular orientation. It is further noted that  FIG. 2A  shows a longitudinal centerline  190  of transceiver  102  that is used herein as a reference for describing embodiments of the present invention.  
         [0025]      FIG. 1  shows the engagement of transceiver  102  to a host board  118  using a rail  120 . In an embodiment compliant with the X2 MSA, the X2 MSA defines the configuration of rail  120 . An X2 MSA compliant rail  120  is approximately 37 millimeters (mm) wide, 77 mm long, and 7 mm high.  
         [0026]     Rail  120  allows unblocked airflow over the full length of the top surface of transceiver  102 . Transceiver  102  may be mounted on the front panel, mid-board, or on a conventional Peripheral Component Interface (PCI) of a compact PCI blade. Rail  120  includes opposing engagements windows  122 A and  122 B. As discussed further below, latches  108 A and  108 B fit into engagement windows  122 A and  122 B, respectively, for securing transceiver  102  to rail  120 . Tabs  130 A and  130 B of rail  120  fit into corresponding grooves  105 A and  105 B on opposing sides of heat sink  104  for aligning transceiver  102  with rail  120 .  
         [0027]     Transceiver  102  includes heat sink  104  coupled to an optics assembly  112  and a Printed Circuit Board (PCB) assembly  114 . In one embodiment, heat sink  104  includes a single piece formed from metal. Heat sink is formed to hold optics assembly  112 , PCB assembly  114  and latching mechanism  103 .  
         [0028]     In general, transceiver  102  converts between optical and electrical signals. Optics assembly  112  may be connected to optical fiber, or other optical waveguides, for sending and receiving optical signals. PCB assembly  114  connects to a socket  116  for sending and receiving electrical signals. PCB assembly  114  includes a board-edge connector  124  that fits into socket  116 .  
         [0029]     Referring to  FIG. 2B , latching mechanism  103  includes a handle  106 , opposing latches  108 A and  108 B, and opposing springs  110 A and  110 B. Latches  108 A,  108 B and springs  110 A,  110 B fit into cavities  140 A and  140 B of heat sink  104 . Portions of handle  106  fit into recesses at the bottom of cavities  140 A and  140 B.  
         [0030]     In one embodiment, latches  108 A and  108 B are each molded as a single plastic piece using injection molding. In another embodiment, handle  106  is molded using plastic injection molding. In yet another embodiment, springs  110 A and  110 B are formed from sheet metal.  
         [0031]     Latches  108 A,  108 B and springs  110 A,  110 B are identical. Thus, there is not a “left” or “right” part, but the latches and springs are interchangeable. Such a design reduces manufacturing costs and makes assembly fast and easy since the latches and springs are manufactured to fit on either side of the latching mechanism  103 . Symmetrical latches and springs also reduce occurrences of incorrect assembly. It will be understood that embodiments of the invention that are discussed in terms of the “A” side of latching mechanism  103 , such as latch  108 A, may include mirrored embodiments on the “B” side of latching mechanism  103 , such as latch  108 B.  
         [0032]     Latch  108 A includes a knife-edge pivot  109 A. In one embodiment, the top and bottom of the knife-edge pivot  109 A include a raised protrusion that fits into a well in cavity  140 A (discussed further below). The raised protrusion is on the top and bottom of latch  108 A. In one embodiment, latch  108 A is a single piece of plastic that does not utilize a separate axle piece. Latch  108 B includes a corresponding knife-edge pivot  109 B.  
         [0033]     Latch  108 A also includes a latch end  111 A that fits through engagement window  122 A for retention of transceiver  102 . Handle  106  includes a slot  107 A and  107 B for receiving one end of spring  110 A and  110 B, respectively. Latch  108 A and spring  110 A fit into cavity  140 A of heat sink  104 . Latch  108 B and spring  110 B into cavity  140 B.  
         [0034]     Referring to  FIG. 3 , when fully assembled, a PCB cover  150  fits over PCB assembly  114  and a portion of optics assembly  112 . An optics assembly cover  152  fits over a portion of optics assembly  112 . In one embodiment, latches  108 A,  108 B, and springs  110 A,  110 B, are captured in cavities  140 A and  140 B by PCB cover  150 . Thus, the components of latching mechanism  103  are not attached to each other using glue or fasteners, but fit together within cavities  140 A and  140 B.  
         [0035]     In one embodiment, latch mechanism  103  may use a drop-in assembly. Glue, screws, fasteners, or the like, are not used to connect components of latching mechanism  103 . Latch  108 A may be placed into cavity  140 A. Spring  110 A may then be positioned in cavity  140 A with one end of spring  110 A dropped into slot  107 A. Thus, the latch  108 A and spring  110 A engage each for retention and retraction of transceiver  102 , but latch  108 A and spring  110 A are not affixed to each other. Similarly, spring  110 A is not affixed to handle  106 , but rather engages handle  106  via slot  107 A.  
         [0036]     Embodiments of the latching mechanism described herein may use inexpensive parts. Further, these parts are easy and quick to assemble into latching mechanism  103 . The lower assembly time equates to lower manufacturing costs. In one embodiment, it is estimated that manufacturing at high volume (e.g., 200,000 pieces) may cost about $1.40 per latching mechanism (that is, handle  106 , springs  110 A,  110 B, and latches  108 A,  108 B).  
         [0037]     Turning to  FIGS. 5, 6A ,  6 B,  6 C,  7 A,  7 B and  7 C, embodiments of the functioning of latching mechanism  103  will be discussed.  FIG. 5  illustrates a bottom view of handle  106  and heat sink  104  without latch  108 A and spring  110 A.  FIGS. 6A-6C  illustrate an embodiment of pushing transceiver  102  into rail  120  for retention of transceiver  102 .  FIGS. 7A-7C  show an embodiment of retraction of transceiver  102  from rail  120  using the latching mechanism  103 . It will be understood that FIGS.  5 ,  6 A- 6 C, and  7 A- 7 C are not to scale or necessarily in proportion. While embodiments of latch  108 A and spring  110 A are discussed below, it will be understood that opposing latch  108 B and spring  110 B operate in a similar fashion.  
         [0038]     Turning to  FIG. 5 , cavity  140 A includes a well  502 A for receiving latch  108 A. In one embodiment, well  502 A is an indentation molded into heat sink  104  that may receive a raised protrusion of knife-edge pivot  109 A. Handle  106  includes slot  107 A. A portion of handle  106 , shown at  506  with a dotted line, is generally flush with the bottom of cavity  104 . Latch  108 A and spring  110 A ride on top of handle portion  506 .  
         [0039]      FIG. 6A  shows a bottom view of latching mechanism  103  as transceiver  102  is being pushed into rail  120 . Grooves  105 A and  105 B of transceiver  102  have been lined up with corresponding tabs  130 A and  130 B of rail  120 . Before latch end  111 A of latch  108 A reaches rail  120 , latch end  111 A protrudes out of heat sink  104  by spring force from spring  110 A. For example, in  FIG. 1 , latch end  111 A of latch  108 A extends out of heat sink  104 .  
         [0040]     In  FIG. 6A , a portion of rail  120  pushes against latch end  111 A, forcing latch  108 A into cavity  140 A of heat sink  104 . Latch  108 A pivots about knife-edge pivot  109 A when retracting into cavity  140 A. Knife-edge pivot  109 A turns within well  502 A.  
         [0041]     Turning to  FIG. 6B , latching mechanism  103  is in a retention position. Latch end  111 A extends from heat sink  104  into the engagement window  122 A of rail  120 . A spring force of spring  110 A pushes against latch  108 A to keep latch  108 A in the retention position.  
         [0042]     In one embodiment, latching mechanism  103  includes a self-locking geometry against a pull-out force placed on transceiver  102 . In one embodiment, this self-locking geometry includes an angled wall  602 . Angled wall  602  is a wall of heat sink  104  and also serves as a wall of cavity  140 A opposite from handle  106 .  
         [0043]     Angled wall  602  angles away from handle  106  to widen latch window  504 .  FIG. 6C  shows angle  606  formed between angled wall  602  and reference line  604 , where reference line  604  is normal to longitudinal centerline  190  of transceiver  102 . In one embodiment, angle  606  of angled wall  602  is approximately 2 degrees.  
         [0044]     Angled wall  602  aids in the retention of transceiver  102 . If transceiver  102  is moved without using the retraction mode of latching mechanism  103 , then angled wall  602  guides latch  108 A away from the transceiver longitudinal centerline  190  and into engagement window  122 A. Latch  108 A may more easily move into the engagement window  122 A then swing against angled wall  602  to retract into cavity  140 A.  
         [0045]     In another embodiment of the self-locking geometry, latch  108 A is slightly shorter in length than cavity  140 A. Also, well  502 A may be larger than the pivot protrusion of latch knife-edge pivot  109 A. In this embodiment, latch  108 A may shift slightly within cavity  140 A. In the retention mode of latching mechanism  103 , this “slight play” of latch  108 A aides in the retention of transceiver  102 . Referring to  FIG. 6B , when transceiver  102  is pulled from rail  120  without use of handle  106 , latch end  111 A pushes against rail wall  608 . The “slight play” of latch  108 A may shift latch  108 A within cavity  140 A (and well  502 A) so that latch  108 A pushes against angled wall  602 . Thus, friction between latch  108 A and angled wall  602  helps prevent latch  108 A from moving into cavity  140 A. As discussed below, this friction between latch  108 A and angled wall  602  is released during the retraction of transceiver  102  using latching mechanism  103 .  
         [0046]     Turning to  FIGS. 7A-7C , the retraction of the transceiver  102  is shown. In  FIG. 7A , handle  106  is being pulled to remove transceiver  102  from rail  120 . As handle  106  is pulled, spring end  710 A is dragged along latch  108 A. In  FIG. 7A , spring  110 A starts at the retention position, shown by the dotted line. It is noted that latch end  111 A stills extends from heat sink  104  while spring  110 A is traveling along latch  108 A.  
         [0047]     Turning to  FIG. 7B , spring end  710 A has reached latch end  708 A. It is noted that latch end  111 A stills extends from heat sink  104  into engagement window  122 A. Latch end  708 A has a ramped end so that spring end  710 A does not climb over latch end  708 A.  
         [0048]     Referring to  FIG. 7C , handle  106  has been pulled slightly more to actuate the retraction of latch  108 A. During the actuation, spring end  710 A pushes against latch end  708 A. Latch  108 A pivots at the knife-edge pivot  109 A and swings into cavity  140 A. At this point, transceiver is no longer retained by rail  120  and may be completely pulled from rail  120 .  
         [0049]     In an embodiment of latching mechanism  103  having self-locking geometry, the “slight play” of latch  108 A may also aid in the transition from retention to retraction as shown in  FIGS. 7B and 7C . In  FIG. 7B , latch  108 A may shift slight to the left to move latch  108 A away from angled wall  602  so the latch  108 A is not touching angled wall  602 . Thus, when latch  108 A pivots to the retraction position, as illustrated in  FIG. 7C , latch  108 A may swing freely within cavity  140 A without rubbing against angled wall  602 .  
         [0050]     It will be appreciated that spring  110 A provides dual functionality. In the retention mode of latching mechanism  103 , spring  110 A provides a spring function to push latch  108 A into the engagement window  122 A. In the retraction mode, spring  110 A acts as an actuator to translate the movement of handle  106  into the retraction of latch  108 A into heat sink  104 .  
         [0051]     Embodiments of latching mechanism  103  provide a mechanism to retain an optical device in a corresponding rail without use of glue, fasteners, or the like. In one embodiment, latching mechanism  103  may be constructed using a drop-in assembly. In another embodiment, components of latching mechanism  103  may be symmetrical and thus, inexpensive to manufacture.  
         [0052]     Turning to  FIG. 8 , a system  800  utilizing a latching mechanism as described herein is illustrated. A switch  802  is connected to an optical network  804  by optical link  803 . In one embodiment, optical link  803  includes one or more optical fibers. Switch  802  may be connected to one or more computer systems  806  and/or one or more phone devices  808 . Switch  802  converts between optical signals of optical network  804  and electrical signals used by computer systems  806  and phone devices  808 . Computer system  806  includes a router, a server, a host, or the like. In one embodiment system  800  includes a Dense Wavelength Division Multiplexed (DWDM) system.  
         [0053]     Switch  802  may include one or more transceivers  810  having a latching mechanism as described herein. In one embodiment, transceiver  810  includes a transceiver compliant with the X2 MSA.  
         [0054]     Transceiver  810  includes an optical interface  822  for sending and receiving optical signals to/from optical network  804  using optical link  803 . Optical interface  822  is coupled to optical receiver  818  and optical transmitter  820 . Optical receiver  818  and optical transmitter  820  are coupled to a Physical Medium Attachment (PMA)  814 . PMA  814  includes a multiplexer/demultiplexer. The multiplexer may interleave multiple channels into a serialized data transmission to be sent by optical transmitter  820  while the demultiplexer separates a serialized data transmission received from optical receiver  818  into two or more channels.  
         [0055]     PMA  814  is also coupled to electrical interface  812 . Electrical interface  812  is used to electrically connect transceiver  810  to a host board of switch  802 . In one embodiment, electrical interface  812  may include a board-edge connector.  
         [0056]     A control system  816  is coupled to electrical interface  812 , PMA  814 , optical receiver  818 , and optical transmitter  820 . In one embodiment, control system  816  is implemented using a microcontroller. Control system  816  may make adjustments to components of transceiver  810  based on changes in environmental temperature or changes in the configuration of switch  802 .  
         [0057]     The above description of illustrated embodiments of the invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various equivalent modifications are possible, as those skilled in the relevant art will recognize. These modifications can be made to embodiments of the invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification. Rather, the following claims are to be construed in accordance with established doctrines of claim interpretation.