Abstract:
An optical fiber connector system includes first and second mateable connectors ( 12, 14 ) with fiber blocks ( 32,72 ) that hold optical fiber termini ( 50 ), wherein forward (F) movement of the second connector housing ( 70 ) toward the first housing ( 30 ) results in automatic latching together of the fiber blocks with the latches taking the forces of termini springs that have been partially compressed. The second fiber block ( 72 ) can slide within the second housing ( 70 ) between front and rear positions, and is held in the front position by a cam ( 90 ) that engages a free end ( 104 ) of a cam follower arm ( 103 ) of the second housing. As the connectors mate, a rigid second fiber block latch ( 100 ) deflects a resilient first housing latch end ( 62 ) and rides forward of it until faces of the blocks are close together. The second housing continues to be pushed forward until a latch blocker ( 122 ) of the second housing prevents the first housing latch from deflecting to release the second fiber block, to thereby hold the fiber blocks close together. When the cam follower ( 104 ) on the second housing deflects around the cam ( 90 ) on the second block, the second block is released and it moves rearwardly a small distance so the second fiber block latch abuts the first housing latch to take the forces of the partially compressed springs.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    One type of optical fiber connector system includes first and second housings that each holds a fiber block with optic termini therein, with one set of termini being spring biased towards the other termini. When the second housing is moved into the first housing, the tips of fiber-holding ferules abut. The second fiber block is usually moved forwardly until it is close to the front of the first fiber block, with the second fiber block then moving rearward a small distance until the forces of the springs are transmitted between the two housings. This avoids requiring the circuit boards on which the connectors are mounted, to apply constant forces to overcome the partial compression of the termini springs. A variety of mechanisms have been suggested for accomplishing the functions of keeping the termini pressed together while the spring forces are maintained by engaging portions of the two connectors, but prior mechanisms have been complicated and often awkward to use. A system that accomplished the required function, but which was simple and compact, would be of value.  
         SUMMARY OF THE INVENTION  
         [0002]    In accordance with one embodiment of the present invention, an optical fiber connector system is provided which enables a second connector to be mated to a first one by simple forward movement of the second connector housing, the connectors then automatically latching in a position wherein optical termini of the two connectors firmly abut one another by compression of springs, and yet the spring compression forces are withstood by engagement of the two connectors, in a simple and compact latching arrangement. The first housing has a first housing latch and the second fiber block has a second fiber block latch that can deflect the first housing latch as the connectors mate, until the second fiber block latch lies forward of the first housing latch. Further forward movement of the second connector results in a latch blocker on the second housing preventing the first housing latch from deflecting to release the second fiber block latch. This assures latching together of the two fully mated connectors, and with the spring forces taken by the engaged first housing latch and second fiber block latch.  
           [0003]    The second fiber block latch can slide within the second housing. However, a cam retains the second fiber latch in its forward position. The cam on the second fiber block latch has front and rear surfaces that each engage the free ends of arms of the second housing to deflect them out of the way as the second fiber block moves forward or rearward between its two extreme positions. In one arrangement, the rear surface of the cam on the second fiber block forms a ramp that deflects the latch arms outwardly, while the front surface of the second fiber block cam forms a wedge that deflects the arm free ends apart.  
           [0004]    The novel features of the invention are set forth with particularity in the appended claims. The invention will be best understood from the following description when read in conjunction with the accompanying drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0005]    [0005]FIG. 1 is an exploded isometric view of an optical fiber connector system of the present invention, with the first connector mounted on a mother board and the second connector shown spaced from the daughter board on which it is usually mounted.  
         [0006]    [0006]FIG. 2 is an isometric view of the system of FIG. 1, which each connector mounted on its corresponding circuit board, and with the two connectors fully mated.  
         [0007]    [0007]FIG. 3 is an exploded view of the second connector of the system of FIG. 1.  
         [0008]    [0008]FIG. 4 is an exploded isometric view of the second connector of FIG. 3, with only a portion of the second housing shown and being shown in a sectional isometric view.  
         [0009]    [0009]FIG. 5 is an exploded partial sectional isometric view of the two connectors of FIG. 1, and also showing, in phantom lines, the connectors partially mated.  
         [0010]    [0010]FIG. 6 is a partial sectional view of the two connectors of FIG. 1, showing the second connector approaching the first connector but not yet mated to it.  
         [0011]    [0011]FIG. 7 is a view similar to that of FIG. 6, with minimum spring over-compression and with the second housing about to release the second fiber block.  
         [0012]    [0012]FIG. 8 is a view similar to FIG. 7, but with the termini springs over compressed to a maximum extent.  
         [0013]    [0013]FIG. 9 is a view similar to FIG. 8, but wherein the second connector fiber block has moved rearwardly slightly and the second housing has moved forwardly, so the connectors are in a fully mated final position.  
         [0014]    [0014]FIG. 10 is an exploded isometric view of a second connector of another embodiment of the invention, wherein the cam followers on each side of the second housing are deflected vertically apart.  
         [0015]    [0015]FIG. 11 is a side elevation view of the assembled connector of FIG. 10, showing a pair of cam follower arms.  
         [0016]    [0016]FIG. 12 is an isometric view of the second fiber block of the connector of FIG. 10. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]    [0017]FIG. 1 illustrates an optical fiber connector system  10  of the present invention, which includes first and second connectors  12 ,  14 . Each connector is intended to mount on a circuit board  20 ,  22 . The first circuit board  20  may be referred to a mother board, while the second circuit board  22  may be referred to as a daughter board. The first connector is a right angle connector in that its mating axis  24  is normal, or perpendicular, to the planes of the faces of the first circuit board  20 . The second connector  14  has a mating axis  26  that is concentric with axis  24  and parallel to the planes of the faces of the second circuit board  22 . Each connector is symmetrical about a vertical plane that passes through its axis  24  or  26 .  
         [0018]    The first connector  12  includes a first housing  30  and a first fiber block  32 . The first fiber block  32  includes two block parts  34 ,  36  which are installed from the rear end  40  of the first housing until latch retainers  42  hold the second block part  36  in place. The first connector includes a plurality of optical termini  50  with ferules  52  having tips  54  where the fiber tips are located. The ferules project rearwardly R from the first fiber block  32 .  
         [0019]    The first housing  30  has a pair of guides  60  at its laterally L opposite sides, and has first housing latches  62  at its laterally opposite sides. The first latches  62  include longitudinally M elongated latch arms  64  that allow the free rear ends  65  of the latches to deflect. The guides  60  have slots  66  that are useful in the latching operations described below.  
         [0020]    The second connector  14  includes a second housing  70  and a second fiber block  72 . The second fiber block is slideable in forward F and rearward R directions in the second housing. The rearward position of the second fiber block is indicated at  72 R while its forward position is shown in solid lines in FIG. 1. The second housing has a plurality of feet  80  that fit into holes  82  in the second circuit board  22 . The first housing fits into a square hole formed in the first circuit board.  
         [0021]    [0021]FIG. 4 shows that the second fiber block  72  has a cam  90  at each of its laterally opposite sides, each cam having front and rear cam surface  92 ,  94 . The second housing  70  has a pair of cam follower devices  102  formed by free rear ends, or cam followers  104  of resilient arms  103 . The front ends of the arms merge with the rest of the housing. When the second fiber block  72  moves to its forward position, the front cam surface  92  passes the arm free ends  104  and deflects them outwardly O. When the second fiber block moves to its rearward position, the rearward cam surface  94  moves across the arm free ends  104  and again deflects them outwardly. The second fiber block also has a second fiber block latch  100  which is fixed to the rest of the second fiber block, and which is used to hold the second fiber block to the first one.  
         [0022]    [0022]FIG. 5 shows portions of the first and second connectors  12 , 14  in solid lines when they are spaced apart, with portions of the second connector shown at  14 B in the course of mating the connectors. When the second connector  14  is moved forwardly F towards the first connector to mate with it, the guides  60  of the first connector move into guide-receiving slots  110  in the second connector housing  70 . Further forward movement of the second connector results in the second fiber block latch  100  moving against the first housing latch  62 . The first housing latch  62  has a resilient latch arm  64  that deflects in an outward O lateral direction to allow the second fiber block latch  100  to pass forward of the first housing latch  62 , to achieve the position shown in phantom lines in FIG. 5.  
         [0023]    When the second connector has achieved the position  14 B of FIG. 5, the second connector can still move further forward, until a front end  112  of the second fiber block at the position  72 B lies very close to a front end of the first fiber block  32 . Such slight additional forward movement of the second connector from the position  14 B results in the free end  104  of the cam follower  102  deflecting around the cam  90 . Until such forward movement occurs, the free end  104  of the cam follower cannot deflect laterally outward O because such outward movement is blocked by a rear end  120  of the guide  60  of the first housing. When the free end  104  is slightly further forward and deflects around the cam  90 , a latch blocker  122  of the second housing moves into a space  124  between the first housing latch arm  64  and an outer side  126  of the first housing  30 . Such forward movement of the latch blocker  122  prevents the first housing latch  62  from deflecting outwardly O, thereby preventing the second fiber block latch  100  from moving rearwardly.  
         [0024]    FIGS.  6 - 9  show the sequence of operation of the connectors as the second connector is moved forwardly to latch to the first one. FIG. 6 shows the second connector  14  approaching the first connector  12 . The second fiber block  72  is in its initial, forward position relative to the second housing  70 . In particular, the second fiber block latch at  100  is still rearward of the first housing latch  62 , and the block faces  112 ,  113  are widely spaced. As the termini springs are compressed, the free end  104  of the cam follower is prevented form moving outwardly O by the rear end  120  of the guide  60  on the first housing.  
         [0025]    [0025]FIG. 7 shows the first connector at  14 B, which has moved forwardly from the position of FIG. 6, so the block faces  112 ,  113  are closer together, although still spaced apart. The second fiber block latch at  100 B, has passed forward of the first housing latch  62 , and has moved slightly beyond the first housing latch to leave a small gap  130 B between them. During such forward movement of the second connector  14 B, the person connecting the connectors has pushed the second connector housing at  70 B forwardly F. The free end  104 B of the cam follower  102 B tends to deflect around the cam  90  of the second fiber block, but the rear end  120  of the second connector housing guide  60  prevents such deflection of the cam follower front end at  104 B. The front tip of the latch blocker  122  has reached a position to prevent outward deflection of the second fiber block latch  100 .  
         [0026]    [0026]FIG. 8 shows the connectors when the second connector at  14 C has moved even further forward, until the block faces  112 ,  113  almost abut one another (e.g. spaced 0.1 mm apart), which is as far forward as the second fiber block moves. In the position of FIG. 8, the front end  104 C of the cam follower at  102 C lies opposite the opening  66  in the first housing guide  60 . As a result, the free end  104 C of the cam follower deflects in the direction O around the cam  90  of the second fiber block, thereby allowing the second housing to move further forward. Such further forward movement allows the latch blocker  122  of the second housing to move securely beside the first housing latch  62  to prevent the first housing latch  62  from deflecting in the direction O.  
         [0027]    [0027]FIG. 9 shows the latch blocker  122  lying immediately outside the first block latch  62 . The second housing at  70 D cannot move any further forward because stops on the second housing and first connector abut, as when an edge of the daughter board  22  abuts the first housing. The second fiber block at  72 D has moved slightly rearward from its position in FIG. 8 due to the forces of the termini springs  154 , and due to the cam  90  of the second fiber block  72 D not being pushed forward by the latch free end  104 D. The second fiber block has moved rearward R until its cam  100  has been stopped by the latch end  62 . The engagement of the cam  100  with latch  62  results in all of the force applied by the terminus springs  154  being born by such engagement of the cam  100  with the latch  62 .  
         [0028]    When the connectors are in the fully mated final position of FIG. 9, the connectors can be unmated by a person pulling the second connector housing  70 D in a rearward direction R. The cam follower  104 D on the second connector housing will move rearward of the cam  90 . Until then, the second fiber block at  72 D cannot move rearward because the latch block  122  prevents the first housing latch  62  from deflecting. However, when the cam follower  104 D moves rearward of the cam  90 , the latch blocker  122  moves rearward by a like amount so latch  62  is free to deflect and release the first latch  62  so the entire second connector can move rearward.  
         [0029]    When the second connector is moved rearwardly out of engagement with the first connector, the front end  104 D of the cam follower device  102 D has moved rearward of the cam  90 , and the second fiber block lies in its forward position, wherein the second connector is ready for again mating with the first connector.  
         [0030]    The connector system is of compact and simple construction. As shown in FIG. 1, the only moveable part (during mating and unmating) of the first connector is the latch arm  64  that can flex outwardly. As shown in FIG. 5, the only moveable parts of the second connector are the second fiber block  72  which can shift forward and rearward, and the cam follower  102  which can deflect. Furthermore, the connectors are easily mated and unmated, with mating requiring that the second fiber block lie in its forward position, which it assumes when unmating the connectors. The relative forces for mating and unmating are determined by the inclines of the front and rear incline surfaces  92 ,  94  of the cam  90 , the termini springs, and friction between components.  
         [0031]    FIGS.  10 - 12  illustrate a second connector  200  of another embodiment, with a modified second housing  202  and modified second fiber block  204 . Instead of providing a single cam follower device at each side of the second housing, applicant provides an arrangement  206  with two cam follower devices  210 ,  212 , each with a resilient arm  214 ,  216  and with a free rear end  220 ,  222  forming a cam follower. The arms can not only deflect outwardly O, but can deflect vertically away from each other.  
         [0032]    The second fiber block  204  has a cam  230  with a rear side  232  that is inclined to extend at a forward F and outward O incline, to deflect the cam followers  220 ,  222  outwardly O as in the embodiment of FIGS.  1 - 9 . However, the cam has a front side with an upper surface  242  that extends at a forward F and downward D incline, and has a lower surface  244  that extends at a forward F and upward U incline.  
         [0033]    [0033]FIG. 11 shows that when the second housing  202  moves rearward R (but the block  204  does not move) during unmating of the connectors, that the free ends, or cam followers  220 ,  222  move against the upper and lower surfaces  242 ,  244  of the cam  230  on the second fiber block  204 . The cam followers  220 ,  222  then deflect apart to positions  220 A,  222 A until the cam follower ends pass the cam  230 . This has the advantage that disengagement can readily occur by pulling the second housing rearwardly without requiring it to be first pushed forwardly to push the second fiber block to its overtravel position. It would be possible to use only a single cam follower device such as  210  at each side. However, two of such devices whose arms deflect in opposite directions, avoids cocking the parts of the second connector, especially during unmating.  
         [0034]    In a connector that applicant has constructed and tested, the first connector housing  30  (FIG. 1) had a maximum width and height that were each 17.8 mm, with other dimensions relative to the width and height of the first housing as illustrated in the drawings. The connectors were found to be rugged and easily operable in a natural manner.  
         [0035]    Although terms such as “up” and “down” have been used to describe the invention as it is illustrated, the invention can be used in any orientation.  
         [0036]    Thus, the invention provides a latching and unlatching fiber optic connector of simple and compact construction, and which can be operated by natural movements which involve pushing the second connector housing forwardly to mate the connectors and pulling the second connector housing rearwardly to unmate the connectors. The connector has a minimum number of moveable or deflectable parts.  
         [0037]    Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art, and consequently, it is intended that the claims be interpreted to cover such modifications and equivalents.