Abstract:
A latch mechanism using a natural unlatching, releasing, pull movement has a slidable latch release which is carried on a device being latched, such as an electronic module. This slidable latch release has a pair of recesses or cavities at least partially defining cams that engage and displace a latch member from engagement with a latching surface on the device being latched. A latch release member is provided with a pair of wing members that are resilient and are deformed as a result of movement of the latch release relative to the latched device. Deformation provides a bias to restore the latch release member to a position capable of permitting latching upon the reinsertion of the device into a host device, such as a computer or the like.

Description:
CROSS REFERENCE TO RELATED UNITED STATES PATENT APPLICATIONS 
     The following are related co-pending United States patent applications: 
     REMOVABLE SMALL FORM FACTOR FIBER OPTIC TRANSCEIVER MODULE CHASSIS, Ser. No. 09/489,870, filed Jan. 20, 2000, by Scott M. Branch, David P. Gaio and William K. Hogan; 
     REMOVABLE LATCH AND BEZEL ELECTRO-MAGNETIC INTERFERENCE GROUNDING FEATURE FOR FIBER-OPTIC TRANSCEIVERS, Ser. No. 09/410,786, filed Oct. 1, 1999, by Scott M. Branch, David P. Gaio and William K. Hogan; 
     REMOVABLE SMALL FORM FACTOR FIBER OPTIC TRANSCEIVER MODULE AND ELECTROMAGNETIC RADIATION SHIELD, Ser. No. 09/489,184, filed Jan. 20, 2000, by Scott M. Branch, David P. Gaio and William K. Hogan; 
     PIVOTING TYPE LATCH FOR REMOVABLE ELECTRONIC DEVICES, Ser. No. 09/591,640, filed Jun. 9, 2000, by Scott M. Branch, Leland L. Day, David P. Gaio, Michael F. Hanley and William K. Hogan; 
     PULL TYPE LATCH MECHANISM FOR REMOVABLE SMALL FORM FACTOR ELECTRONIC MODULES, Ser. No. 09/657,214, filed Sep. 7, 2000, by Scott M. Branch, David P. Gaio, Michael F. Hanley and William K. Hogan; and 
     PULL TYPE LATCH MECHANISM FOR REMOVABLE SMALL FORM FACTOR ELECTRONIC MODULES, Ser. No. 09/669,624 filed Sep. 25, 2000 by Scott M. Branch, David P. Gaio, Michael F. Hanley and William K. Hogan, all of which are incorporated herein in their entireties by this reference. 
     FIELD OF THE INVENTION 
     This invention relates to the field of connecting cables or other devices to computers and, more specifically, to the latching of connectors and connections together to ensure reliable service and uninterrupted data transmission and reception. 
     BACKGROUND OF THE INVENTION 
     Increasingly, computers and servers are being interconnected with other computers and servers to form communications and data networks. Prodigious amounts of data and other communications are transmitted and received over such networks and require reliable connection of coaxial or fiber-optic cables either to the computer/server or to interface devices connected to the computer/server to insure continued and uninterrupted connections. In order to provide the services or data that a computer or server is intended to provide to the remote computers upon demand, networked computers or servers typically operate continuously, twenty-four hours a day. 
     Easy connection/disconnection and reliable cable connections are necessary to permit rapid, easy and reliable changing of cables as needs arise. One approach, which is rapidly becoming a standard within the industry, utilizes a transceiver module to receive signals from the network cable and to transmit signals to the computer or server, or vice-versa. 
     This type transceiver module may be designed in various versions, but all are compatible with the particular connector and port in a particular computer or server. Some transceivers can receive optical signals and output electronic signals to the computer and vice-versa. Other transceiver modules may be designed to receive electronic signals from the network cables and output or transmit computer compatible electronic signal and vice-versa. Transceiver modules are inserted into and connected to the data ports of a computer or server. The transceiver modules must be reliably latched into data ports and be retained against reasonable forces exerted on cables without being disconnected from the data ports. At the same time, the latching of the transceiver modules must not be so resistive to unintentional disconnection forces that the transceiver module is damaged if the cables are pulled excessively. 
     The latching devices preferably are disposed on the transceiver modules so that these latching devices are removed from the host device whenever the transceiver module is removed. Therefore, the latch itself cannot be left in the data port, unprotected as such, and face the possibility of breakage from impacts or forces exerted thereon. Such breakage is a problem presented by designs wherein the latch mechanism is not removed from the data port whenever a transceiver module is removed. Remaining as part of the host device, a latch release member is obviously exposed to damage as it will project from the host device without a protective device to shield the latch device. 
     The latch is designed and created to be an intentionally “weak link” in the retention apparatus to desirably protect from destructive forces, the more expensive components, such as a transceiver module; those forces include those exerted by a person tripping over the cables or pulling excessively hard on the cables. 
     OBJECTS OF THE INVENTION 
     It is an object of the invention to latch a modular device into a predetermined position or receptacle relative to a host device. 
     It is another object to the invention to enable a latch to hold the latched device in a latched condition pending release of the latching member from the modular device. 
     It is an additional object of the invention to effect latching of the latch mechanism as a part of an inserting motion. 
     It is still another object of the invention to effect unlatching as part of an extracting movement. 
     It is a still further object of the invention for the latch mechanism to be easily replaceable on the device being latched to the host device. 
     Other Objects of the Invention will become apparent from a complete understanding of the structural and operational aspects of the invention provided by the attached drawings and the Detailed Description of the Invention below. 
     SUMMARY OF THE INVENTION 
     This Summary of the Invention is intended to present a succinct and summary description of the invention and is not intended to be a basis for limiting of the invention in any manner. 
     An electronic module is latched to the host device by a latch spring with an inwardly turned end to engage a surface on the electronic module and block movement of the electronic module, thereby insuring that the electronic module remains inserted into and electronically engaged with the electronics within the host device. This connection allows the optical signals or other signals of a network not only to be received, converted and utilized by the host device but also to convert and transmit the signals of the host device to a form usable on the network. 
     The latch is formed of a portion of an electro-magnetic interference cage or shield or is fabricated of a resilient cantilevered member with an end thereof formed to create a latch portion extending substantially transverse to the axis of movement of the electronic module and disposable in the path of transverse surface, blocking movement of the electronic module in a disconnecting direction. The cantilevered member in the form of a beam spring may be separately formed and attached to some other rigid structure in the host device. 
     The latch is controlled to deflect and to release the electronic module for extraction or removal of the electronic module by a latch release member. The latch release member is attached to and carried by the electronic module in a manner that permits movement relative to the electronic module. The latch release member is preferably spring-biased to a retracted position which causes disengagement from the latch member, permitting the latch member to flex and restore to the effective, latching position. 
     The latch release member may be pulled in a natural removal or extraction direction to cause camming surfaces on the latch release member to engage and cam the latch member out of the path of the latching surface on the electronic module and permit the pulling of the latch release member to further pull the electronic module from engagement with and within the host device. 
     The latch release member is dislocated against the force of a restore spring arms extending from the body of the latch release member and are arranged to abut against a juxtaposed surface to better provide the extraction or removal force to the electronic module. 
     The invention permits release and removal of the electronic module from the host device and is accomplished by a natural pulling motion necessary to extract the electronic module. 
     The invention may be implemented into any type of module that must be latched into a host and must be removed from time to time. 
     A more complete understanding of the structure and operation of the latching mechanism of the invention may be gained from the attached drawings and the detailed description of the invention that follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of an electronic module carrying the latch mechanism of the invention disposed relative to a latch bar. 
     FIG. 2 is an isometric view of a portion of an electronic module and the latch release mechanism carried thereby. 
     FIG. 3 is an isometric view of the exposed surface of the latch release member. 
     FIG. 4 is an isometric view of the latch release member from the external grip end thereof. 
     FIG. 5 is an isometric view of the external end of the transceiver module and the grip end of the latch release member of the latch mechanism of the invention. 
     FIG. 6 is an isometric view of the host device and, particularly, the electro-magnetic interference shield and the latch member of the latch mechanism. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     OF THE BEST MODE FOR CARRYING OUT THE INVENTION 
     AS CONTEMPLATED BY THE INVENTORS 
     Referring to FIG. 1, the pull-to-release latch release member pull tab  34  is shown protruding from the transceiver module  10  and illustrates the transceiver module  10  latched into place by the latch member  16 . The transceiver module  10  is shown inserted within the electro-magnetic interference shield or cage  18 . A portion of the electro-magnetic interference cage  18  is formed both to be a cantilevered beam spring, functioning as latch member  16 , and to deflect to permit passage of the transceiver module  10  upon insertion into the electro-magnetic interference cage  18 . 
     Edge  21  of the upstanding portion or finger  20  of latch member  16  engages the transceiver module  10  to latch or retain the transceiver module  10  in the electro-magnetic interference cage  18  and is connected to the electronics (not shown) contained within the housing of the host device  14 . 
     The transceiver module  10  is illustrated mated with a ferrule  60  on the end of a fiber optic cable  62 . The fiber optic cable ferrule  60  is positioned above the pull-to-release latch member  34  to prevent ready access to the release member  34  while the fiber optic cable  62  is connected to the transceiver module  10  and presumably conveying optical signals to and from the transceiver module  10 . 
     Latch member or retention member  16  engaged with the transceiver module  10  resists the unintentional disengagement of the transceiver module  10  from the host device  14  and the unintentional withdrawal of the transceiver module  10  through the bezel  12  of host device  14 . Latch member  16  has an upstanding portion  20  which projects transverse to the path of movement of transceiver module  10  during insertion into and extraction from host device  14 . The upstanding portion  20  of latch member  16  will engage the latch surface  32  formed into the transceiver module  10  to retain and prevent extraction of the transceiver module  10 . 
     FIG. 2 illustrates the pull-to-release member  34  extending from the exposed end of the transceiver module  10  and the arrow indicates the direction of movement of the latch release member  26  for accomplishing the release of the latched condition retaining the transceiver module  10 , whenever the module  10  is inserted into the electro-magnetic interference cage  18  discussed above with reference to FIG.  1 . 
     The transceiver module  10  is provided with slides  38  both to retain the latch release body  28  and to guide its movement thereof along a path parallel to the longitudinal axis of the transceiver module  10 ; this also permits movement of the latch release body  28  parallel to the axis of insertion and withdrawal of the transceiver module  10  into and out of the electromagnetic interference cage  18 , shown in FIG.  1 . 
     The underside of the pull-to-release member  26  is illustrated in FIG.  3 . The latch release member  26  has a longitudinal body  28 , a pull tab  34  on an exposed end and a spring member or spring arms  44  formed into the opposite end of the longitudinal body  28 . The pull tab  34  is formed to permit engagement of its top surface  35  and bottom surface  37  thereof by the thumb and forefinger of a human hand. As illustrated in FIG. 1, the surfaces  35 ,  37  may be any of several different types such as smooth, ridged, textured, checkered or other suitable non-slip engageable surface textures to resist slippage of the thumb and forefinger, thereby insuring a good pulling grasp to unlatch the transceiver module  10  from the latch member  16  of the electro-magnetic interference cage  18  within the host device  14 . 
     Again referring to FIGS. 2 and 3, the latch release member  26  is provided with recesses or cavities  30  in the exposed underside thereof. These recesses  30  are preferably disposed on opposing edges of the exposed side or under surface of the latch release member  26 . This permits the reception into the recesses  30  of portions  20  of the latch member  16  extending from the electro-magnetic interference cage  18  as described earlier with reference to FIG.  1 . 
     The distal end surface  48  of the recess  30  is formed to create sloping cam or ramp surfaces  48 . The camming surfaces  48  may be engaged with the extending portions or fingers  20  of the latch member  16  that are resident within recesses  30  by a withdrawing movement of the latch release member  26 . The camming surfaces  48  act to progressively force the fingers  20  of the latch member  16  out of the recesses  30  and out of interference with the latch surface  32  of the transceiver module  10  whenever the latch release member  26  is translated longitudinally relative to the transceiver module  10 . 
     The fingers  20  are progressively displaced out of engagement with the transceiver module  10  and the spring arms  44  on the distal end of the longitudinal body  28  of the latch release member  26  are caused to flex at the flexure section  50  and act as springs. The spring arms  44  act to return and retain the latch release member  26  in its withdrawn or retracted position relative to the transceiver module  10  (FIG. 1) whenever there are no external forces exerted on the pull tab  34  of the latch release member body  28 . 
     With the latch release member  26  fully retracted, the latch member  16  and, particularly, fingers  20  thereof are free to enter into the recesses  30  and dispose the fingers  20  of latch member  16  in blocking interference with the transceiver module  10 , thereby preventing withdrawal of the transceiver module  10  from the electro-magnetic interference cage  18  and its connection with the host device  14 . 
     Upon release of pulling forces on pull tab  34 , latch release member  26  will be restored, due to the inherent resilience of spring arms  44 , to its retracted position upon release of pulling forces on the tab  34 . 
     Additionally, as best seen in FIG. 2, with the spring arms  44  resident in the slot-like recess  52  in the bottom of the transceiver module  10 , and when the spring arms  44  deflect in response to the movement of the latch release member  26 , the surfaces  46  of the spring arm members  44  and the surfaces  54  of the recess  52  engage and abut to limit travel of the latch release member  26 . In addition to this limiting of longitudinal travel, the engagement of the spring finger surfaces  46  (shown in FIGS. 2,  3 , and  4 ) and the transceiver module surfaces  54 , in FIG. 2, provides a substantial resistance to further deflection of the spring arms  44 . Consequently, such engagement both transfers substantially all of the force exerted on the pull tab  34  to the transceiver module  10  and also provides a very substantial force for extracting the transceiver module  10  from both the electro-magnetic interference cage  18  and those retaining frictional forces exerted on the transceiver module electronic connector (not shown). 
     The latch release member  26  is illustrated in detail in FIGS. 3 and 4. The latch release member  26  is provided with slide members  40 . The slide members  40  guide and stabilize the latch release member  26  during movement of the latch release member  26  relative to the transceiver module  10 . As can be observed in FIG. 2, the form of the slide members  40 , being wedge-shaped projections from the latch release member body  28 , permits easy insertion of the latch release member  26  into the slide channel  42  formed by the transceiver module  10 . 
     Typically, the slide channel  42  is formed into the transceiver module  10  as a part of the molding operation which results in the transceiver module  10  and provides the retention function necessary for the relative movement of the latch release member  26  and the transceiver module  10 . The recess or cavity  52  that accepts the spring arms  44  likewise is molded into the transceiver module  10 . 
     As shown in FIGS. 3 and 4, the latch release member  26  is assembled to the transceiver module  10  by forcing the body  28  of the latch release member  26  between the slides  38  that form a portion of the slide channel  42  of transceiver module  10 , spreading the slides  38  and forcing the wedge-shaped slides  40  on the sides of the latch release member body  28  until the slides  40  pass over the slides  38 , and the slides  38  snap back to shape. Similarly, a broken or damaged latch release member  26  may be removed by spreading the slides  38  and removing the broken or defective latch release member  26  between the slides  38 . Thereafter, a new latch release member  26  may be inserted as previously described, and the significantly more expensive transceiver module  10  may be returned to service by the operator or other relatively unskilled person without the assistance of a technician and the cost of a service call. 
     FIG. 5 shows the pull tab  34  of the latch release member body  28  protruding from below transceiver module  10 . This arrangements protects pull tab  34  and latch release member body  28  any time fiber optic cable  62  and ferrule  60  are connected to the transceiver module  10 , as in FIG.  1 . 
     The operation of the latching mechanism of the invention involves the insertion of the transceiver module  10  into the host device  14 , typically by inserting the transceiver module  10  into the electro-magnetic interference cage  18  and seating the transceiver module  10 . Referring to FIG. 6, the host device  14 , typically a computer or server, provides the latch member  16  for engagement with the latch release member  26 , preferably in the form of a portion of the metal electro-magnetic interference cage  18  or other deflectable member in the form of a cantilevered beam spring  16 . The latching portion  20  of the spring or latch member  16 , extending inwardly toward the transceiver module  10 , slides relative to the transceiver module  10  until passing the latch surface  32  of the transceiver module  10 . Thereafter, the latch member  16  relaxes and flexes to dispose at least a portion  20  of the latch member  16  in a position to block or interfere with the withdrawal of the transceiver module  10 . The latch member  16  extends into the recesses  30  on the body  28  of the latch release member  26 . These actions are best seen in FIGS. 1 and 2. 
     With the transceiver module  10  being latched into position by engagement of portion  20  of latch member  16  with the latch surface  32  and the latch release member  26  fully retracted into the transceiver module  10 , the latch member  16 , particularly, portion  20  is resident in the recesses  30  in the latch release member  26 . 
     Removal of the transceiver module  10  is accomplished by grasping and pulling the pull tab  34  of the latch release member  26 . Whenever the latch release member  26  is translated generally left to right as occurs in FIG. 2, the sloping surfaces  48  engage the edge  21  of portion  20  of the latch member  16  and cause the deflection of the cantilevered beam spring  16  forming the support for the latch surface  22  on portion  20  of the latch member  16 . Upon the deflection to the greatest extent possible by the sloped camming surfaces  48 , the latch member  16  is disengaged from latch surface  32  and the transceiver module  10  may be extracted from the host device  14  by further pulling pull tab  34 . 
     The spring arms  44  will flex relative to the transceiver module  10  to provide a restore movement for the latch release member  26 . Once the latch release member  26  is fully translated for extraction, the spring arms  44  will engage a blocking surface  54  of recess  52 ; such engagement not only will prevent further movement of the latch release member  26  relative to the transceiver module  10  but also will transmit a force exerted on the latch release member  26  to transceiver module  10  to pull the transceiver module  10  from the host device  14  and disconnect the electronic connectors on both the transceiver module  10  and the host device  14 . 
     The spring arms  44  and, particularly, the flexure regions  50  of the spring arms  44  may be sized to break away from the latch release member  26  if an excessive force is applied to the pull tab  34 . This feature insures a weak link in a relatively inexpensive part that can be easily replaced if latch release member  26  is broken or defective. 
     FIG. 6 shows a portion of the host device  14  where the electro-magnetic interference cage  18  is mounted on a circuit board  24  within the host device or computer  14 ; the bottom portion of the electromagnetic interference cage  18  is partially severed longitudinally to form the latch member  16  with the upstanding portions  20  projecting toward or into the space that would be occupied by the transceiver module  10 . The latch surface  22  of the latch  16  is the back side surface of the upstanding portions  20 . 
     The latch member need not be a leaf spring as illustrated if a reciprocal latch member is desired. The same latching function could be attained by a spring-biased member supported by the bezel or housing of the host device. The spring-biased member could be a reciprocally moveable latch member biased by a separate spring and guided by a structure mounted on the interior of the housing. 
     Other modifications of various aspects of the invention may become apparent to one of skill in the art. 
     While the description of the invention has been made with reference to a transceiver module for purposes of the preferred embodiment, other electronic modules or devices may be latched by the use of this design of latch mechanism. 
     Each element of the invention is described with reference to at least one figure of the drawings and it should be understood that description is applicable to the same element in any figure, notwithstanding a lack of specific reference to the element in a particular figure. 
     The detailed description has been made for purposes of disclosure and may not be used to limit in any manner the scope of protection afforded by the attached claims which define the scope of the invention. 
     This description is made of the preferred embodiment of the invention but other embodiments of and modifications and changes to the described invention will come to mind of one skilled in the art, and the modifications and changes do not remove the resulting article from the scope of protection afforded the invention by the attached claims.