Abstract:
A mounting frame system is disclosed that facilitates the mounting of optical connector modules to printed circuit boards. The mounting frame system can include a mounting frame that is configured to attach to a printed circuit board, and is adapted to attach to a connector module. Thus, the mounting frame system can further allow releasable mounting of optical connector modules to the printed circuit board, such that the mounting is achieved in a safe and reliable manner.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    The present disclosure relates to a mounting frame system for the mounting of a, preferably optical, connector module to a printed circuit board (PCB). 
       BACKGROUND 
       [0002]    In many electronic applications, signal lines (such as optical signal lines) are connected to substrates, such as printed circuit boards. The mounting and connection of signal lines, and in particular optical signal lines, to the printed circuit board can require specific connector modules, in particular if the optical signal line, and the respective corresponding optical connector module, is intended to be releasable mountable to the PCB. 
         [0003]    US 2008/0248678 describes a connector fastening arrangement that mounts a connector housing to a printed circuit board. The connector housing comprises a number of electrical contact terminals ending in corresponding solder contact ends that in assembled condition are in contact with respective solder pads of the printed circuit board. The housing of the connector is directly attached to the printed circuit board, namely by means of locking bolts having a crank pin-like configuration including an offset peg portion that protrudes eccentrically with respect to the axis of rotation and which is dimensioned and designed that it can be inserted through a passage hole provided in the printed circuit board. After inserted through the passage hole, the locking bolt is displaced by a rotational movement, such that the offset peg portion moves a part of the locking device under the bottom side of the PCB, thereby locking the connector housing to the printed circuit board. 
       SUMMARY 
       [0004]    In accordance with one aspect of the present disclosure, a mounting frame system facilitates the mounting of in particular optical connector modules to printed circuit boards. The mounting frame can allow a releasable mounting of e.g. an optical connector module to a PCB, such that the mounting is achieved in a safe and reliable manner. 
         [0005]    These and other aspects which will become apparent upon reading the following description are solved by a mounting frame system according to claim  1 . 
         [0006]    According to the present disclosure, a mounting frame system for the mounting of a connector module, in particular an optical connector module, to a printed circuit board (PCB) is provided, which system comprises a mounting frame that is attachable to the surface of the PCB and which is adapted for the mounting of the connector module thereon. The mounting frame can for example be glued and/or soldered onto the surface of the PCB or it can be attached thereon by means of a screw fixation or similar. The mounting frame itself needs not necessarily to be attached releasable on the PCB. In preferred embodiments, the mounting frame comprises an interposer or similar intermediate substrate to provide an electrical interface between the mounting frame and the module. The mounting frame can thus also be considered as a socket and the connector module as the corresponding plug connector. Preferably, the mounting frame comprises an essentially rectangular base frame made for example from plastic, which has on an outside wall thereof at least one locking undercut portion accessible from a peripheral side of the wall and which is designed or formed to provide the female counterpart of a twistlock. As the skilled person recognizes, a twistlock connection usually requires a female part and a male part. The male part in its simplest form is a bolt having a locking protrusion on one end and the female part is provided with a corresponding aperture or opening, which allows the insertion of the locking projection of the male part, if the male part is arranged in a suitable angular orientation with respect to the opening of the female part. After insertion of the respective male part of the twistlock connection, the twistlock can be closed or locked by rotating the male part for a suitable angular amount, like for example 180 degrees, in which orientation it is no longer be possible to remove the male part. Thus, by providing an undercut portion on an outside wall of the base frame the present invention allows to use female twistlock members, which are not fully enclosed apertures provided in the base frame but which are open on at least one side. Due to the inventive construction of a locking undercut provided on the outside wall of the rectangular base frame which is accessible from the peripheral side of the wall, the use of male twistlock members with particularly advantageous locking projections is possible, which can for example be particularly larger than in the above cited prior art and offer thereby a more reliable connection. In addition, preferably, the mounting frame may have a cut-out in the shape of a semi-circle on an outside wall of the base frame, which cut-out allows access to the undercut portion from the top side of the frame. 
         [0007]    The base frame can include a mount or mate assist member adapted to hold a corresponding (optical) connector module in a pre-assembled position. The mount assist member can for example be provided in form of one or more latching arms adapted to latch onto a corresponding portion of a connector module at the beginning of the mating process of module and mounting frame, so that the latching arm(s) latch onto the module before the same is inserted into the fully mated position. The latching arm thus holds the module in close proximity to the mounting frame, whereby for example a manual mounting of the module to the frame is facilitated. Most preferably, at least one pair of latching arms is provided. 
         [0008]    The base frame can be essentially rectangular having walls protruding perpendicular from the surface of the PCB when it is attached thereto. The locking undercut is thereby arranged in an outer peripheral wall of the base frame and accessible from the peripheral side of the wall, i.e. from a direction parallel to the plane defined by the rectangular base frame. In other words, the locking undercut is accessible from a direction which is parallel to the plane defined by the PCB, which carries the mounting frame in assembled condition. Preferably, the mounting frame, respectively the base frame thereof, has a top side and a bottom side. The bottom side of the frame is the side facing the surface of the PCB when mounted thereon and the top side is the side opposite of the bottom side. To facilitate the mounting of the module onto the frame, the top side has preferably at least one cut-out in the shape of essentially a semi-circle, which cut-out allows additionally access to the undercut portion from the top side of the frame. 
         [0009]    The mounting frame system can further include a corresponding (in particular: optical) connector module, which is adapted to be preferably releasable mountable to the mounting frame. To this end, it is preferred that the module comprises at least one male twistlock member adapted to engage the locking undercut to releasable mount the module onto the mounting frame. 
         [0010]    In accordance with certain embodiments, the male twistlock member provided on the module comprises a bolt, which extends through the optical connector module and which bolt is arranged on the module such that it is moveable in axial or longitudinal direction of the bolt and such that it is arranged rotatable around the longitudinal axis of the bolt. Most preferably, the axial or longitudinal extension of the bolt is parallel to the general mating direction of the module, i.e. the bolt is arranged moveable in the mating direction of the module. This facilitates the mounting process, as will be described in more detail below under reference to the figures. A particularly advantageous design is achievable, when the male twistlock member has an upper part projecting from the top face of the optical connector module and a lower part, which projects from the bottom face of the optical connector module. In other words, the male twistlock member, respectively the bolt of the twistlock member, extends completely through at least a part of the module. The upper part of the bolt projecting from the top face of the module is preferably provided with a suitable compression spring. The compression spring rests with one end on the housing of the module and the other end of the compression spring is functionally connected with the upper part of the bolt. Thereby, when moving the bolt in longitudinal direction, (i.e. in mating direction of the module) the compression spring is biased and provides a bias or load force acting in the opposite direction, i.e. in the un-mating direction of the module. The lower part of the bolt in turn comprises a locking projection, which extends perpendicular to the longitudinal axis of the bolt, so that the bolt is held onto the module despite the three of the compression spring. In preferred embodiments, the locking projection of the bolt has for example a semi-circular cross-section in a plane perpendicular to the longitudinal axis of the bolt and offers thereby a particularly large active locking surface and thus a particularly reliable and secure locking function in connection with the corresponding locking undercut of the base frame. 
         [0011]    In accordance with certain embodiments, the optical module comprises an essentially rectangular base shape and has four male twistlock members, arranged in respective four opposite sides of the base, as for example on the four corners of the rectangular base. Correspondingly, also the essentially rectangular mounting frame comprises four undercut portions, i.e. the female counter parts of the twistlock, in alignment with the four male twistlock members of the module. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    In the following, the invention is described exemplarily with reference to the enclosed figures, in which 
           [0013]      FIG. 1  shows a schematic three dimensional view of a mounting frame and an optical connector module; 
           [0014]      FIG. 2  shows the same part as  FIG. 1  in assembled condition; 
           [0015]      FIG. 3  shows a three dimensional detailed view of the mounting frame of  FIG. 1 ; 
           [0016]      FIG. 4  shows the same mounting frame seen from the bottom side; 
           [0017]      FIG. 5  shows a detail of a locking undercut provided on the mounting frame; 
           [0018]      FIG. 6  shows a male twistlock member from different perspectives; 
           [0019]      FIG. 7  shows the optical connector module of  FIG. 1  in a schematic three dimensional view; 
           [0020]      FIG. 8 a - d    shows in a detailed three dimensional view the ocking process of connector module to mounting frame; 
           [0021]      FIG. 9  shows a side view of the connector module assembled to the mounting frame. 
       
    
    
     DETAILED DESCRIPTION 
       [0022]      FIG. 1  shows a mounting frame  10  attached to a printed circuit board (PCB)  70 , Further, an optical connector module  40  is shown, which is not yet assembled to the mounting frame  10 . The PCB  70  is for example a mother board and the mounting frame  10  comprises an interposer  14  as well as contact terminals to establish a signal connection between the mounting frame and for example the conductive traces (not shown) of the PCB  70 . The mounting frame  10  comprises an essentially rectangular base frame  12  having four walls protruding perpendicular from the surface of the PCB in the attached condition as shown. In the outside walls  17  of the base frame—in the shown embodiment at the corners of the rectangular base frame  12 —four locking undercuts  20  are provided, which are accessible from a peripheral side of the wall  17 , i.e. from a direction parallel to the plane defined by the PCB  70  or the rectangular base frame  12 . As will be described in more detail in the following, the undercuts  20  are formed to provide the female counterpart of a twistlock, which is in the shown embodiment of the bayonet type. 
         [0023]    Further, the base frame  12  comprises two mate assist members  30 , which are adapted to hold the connector module  40  in a preassembled position, to facilitate the mating or mounting process. In the shown embodiment, the mount or mate assist members  30  each comprise a pair of latching arms  31 ,  32 , which interact together and are adapted to latch onto a corresponding latching portion  43  of the connector module  40 . 
         [0024]    The connector module  40  comprises a housing  41  having an essentially rectangular housing frame  42 . At the four corners of the housing frame  42  male twistlock members  50  are arranged. Each male twistiock member  50  has a bolt  54  having a locking projection  53  on one end and a handle  52  on the opposite end. The bolt  54  is arranged coaxially in a compression spring  51 . As the skilled person will recognize from considering the figures, the compression spring  51  will bias the bolt against a movement in axial direction of the bolt from the top face of the module towards the bottom face of the module, i.e. in the orientation shown in  FIG. 1  in a downward movement towards the mounting frame  10  (it is clear to the skilled person that the shown elements can in practice be arranged in any spatial orientation and that expressions such as “downwards” are merely used in connection with the figures to facilitate the description). Thereby, the module is spring loaded onto the mounting frame in mounted condition. This spring loaded connection provides particularly advantageous contact normal forces between the socket or frame contacts and the module contacts and provides a facilitated installation and removal of the module from the frame. The male twistlock members  50  extend through the housing frame  42  of the connector module  40 , such that each bolt  54  is moveable in longitudinal direction of the bolt and at the same time rotatable around the longitudinal axis of the bolt. 
         [0025]    The housing frame  42  further comprises latching portions  43 , which are adapted to be engaged by the latching arms  31 ,  32 . Thereby, the mating process of connector module to mounting frame  10  is significantly facilitated: In order to achieve a first attachment or connection of connector module to mounting frame, it is simply sufficient to press the connector module  40  downward towards the mounting frame  10 , until the latching arms  31  and  32  latch onto the latching portion  43 . This arrangement is shown in  FIG. 2 , which shows the connector module  40  mated or mounted to the mounting frame  10 . 
         [0026]    Now turning to  FIG. 3 , the mounting frame  10  is shown in more detail. Also in  FIG. 3 , the mounting frame  10  is attached to the surface of a PCB  70 . One can clearly see from  FIG. 3 , that the mounting frame  10  has a symmetrical design comprising mate assist members  30  on two opposite sides thereof. In the shown embodiment, the mate assist members  30  are integrally formed and monolithic with the base frame  12 . Likewise integrally formed and monolithic with the base frame  12 , namely in the outside walls of the frame, four locking undercuts  20  are provided. As one can take from the figure, the undercuts  20  are accessible from the peripheral side of the wall, due to an opening denoted in the following as access  22 . In addition, in the top side of the mounting frame, i.e. the side visible in  FIG. 3 , semi-circular cut-outs  21  are provided, which additionally allow access to the undercut portion  20  from the top side of the frame. 
         [0027]      FIG. 4  shows the same mounting frame  10  as seen from the bottom side, i.e. from the side which faces the surface of the PCB in the attached condition shown in  FIG. 2 . Thus, the bottom side faces opposite the top side. At the bottom side of the mounting frame a large number of solder balls  15  are provided, which together with the terminals  16  provided on the top face of the mounting frame enable a signal or electrical connection to for example the traces and electronic components of the PCB. 
         [0028]    In  FIG. 4 , one can further see details of the particular shape of the undercuts  20 . Each undercut  20  comprises an arc-shaped, for instance a semi-circular, cavity  25 , which is adapted to receive the locking projections  53  of the male twistlock members  50 . By rotating the male twistlock members around the longitudinal axis of bolt  54 , the locking projections  53  thereof are moved into the semi-circular cavity  25 . To facilitate the locking process, a stop wall  23  is provided and on the opposite end an inclined ramp  24 , which facilitates the movement of the locking projections into the cavity  25 . The embodiment shown in the figures is a most preferred embodiment and represents the to-date best known arrangement. 
         [0029]      FIG. 5  shows another detailed view of undercut  20 . One can see in connection with  FIGS. 6 , which shows a detailed view of a male twistlock member  50  (with the compression spring removed for the sake of clarity), how the member  50  is particularly adapted to interact with undercut  20 . To this end, the male twistlock member  50  comprises a locking projection  53 , which has a semi-circular cross-section in a plane perpendicular to the longitudinal axis of bolt  54 . The handle  52  facilitates the manual rotation and thus locking of the male twistlock members  50  and serves at the same time as fixation for the compression spring. The handle can e.g. be screwed onto the bolt  54 , thereby enabling a simple mounting of the members  50  onto the connector module  40 . Locking projection  53  and semi-circular cavity  25  are correspondingly shaped, such that the locking projection  53  can easily be rotated into the cavity  25  by rotating bolt  54 . However, due to ramp  24  the locking projection  53  remains in the locked position if no external force is applied. 
         [0030]    In  FIG. 7 , the connector module  40  is again shown in a slightly enlarged view without the mounting frame. From this view, it can be seen how the male twistlock members  50  have an upper part  55  projecting from the top face of the connector module and lower part  56  projecting from the bottom thee of the connector module. The compression spring  51  is arranged on the upper part  55  and the locking projection is arranged on the lower part  56 . 
         [0031]    The locking process is in the following explained in more detail under reference to  FIGS. 8( a ) to ( d ) . In  FIG. 8 a    the situation is shown, when the connector module  40  is in a pre-mated position, where the mate assist member  30  of the mounting frame  10  is latched onto latching portion  43 , thereby retaining the connector module  40  in the position shown in  FIG. 8 a   . However, the mate assist member  30  only serves to facilitate the actual locking or mating process, which is achieved by means of the male twistlock members  50  and the corresponding undercuts  20 . In  FIG. 8   a,  the male twistlock member  50  is not yet locked, and the locking projection  53  thereof is arranged above the semi-circular cut-out  21  and extends in a direction away from the corners of the frame. Bolt  54  is however in alignment with the semi-circular cut-out  21 , so that it is possible to manually push the member  50  downwards in the figures, until the locking projection  53  is in alignment with the undercut  20  and adjacent the peripheral access  22  to the undercut. This situation is shown in  FIG. 8 b   . One can see how compression spring  51  is now compressed. In  FIG. 8 c   , the member  50  is rotated around the longitudinal axis of the bolt by approximately 180 degrees. Thereby, the locking projection  53  enters the undercut  20 , respectively the semi-circular cavity  25  formed by the undercut. In the situation of  FIG. 8 c   , male member  50  is still manually compressed downwardly.  FIG. 8 d    shows the completely locked position, when no further pressure is applied on the top of member  50 . One can see from a comparison of  FIGS. 8 c  and  d   , that at  8   d  the compression spring moved the male member  50  slightly upwards in the figure, so that the locking projection  53  now securely rests inside of undercut  20 . The skilled person will recognize that thereby the module is spring loaded onto the mounting frame in this mounted condition. 
         [0032]      FIG. 9  shows the same situation as  FIG. 2 , however seen from a lateral side of connector module  40  and mounting frame  10 .