Abstract:
An optical circuit assembly is composed of a board for mounting an optical circuit element, an optical adapter that connects an optical fiber cable to the optical circuit element, and an adapter supporting member which movably supports the optical adapter. The adapter supporting member allows the optical adapter to move between first and second positions. The first position is located substantially at an edge of the board, and the second position is located above the board away from the edge.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to an optical circuit assembly. More particularly, the present invention relates to an optical circuit assembly provided with an optical adapter to connect an optical module to an optical fiber.  
           [0003]    2. Description of the Related Art  
           [0004]    Optical adapters are used for connecting optical fibers to optical modules. Various structures are proposed for facilitating the connection of an optical adapter and an optical fiber.  
           [0005]    Japanese Laid Open Patent Application (Jp-A-Heisei 5-249345) discloses a print circuit unit provided with optical adapters. As shown in FIG. 1, a print circuit board  101  is provided with an optical adapter  102 . The optical adapter  102  is coupled to an optical fiber cable  103 . The optical adapter  102  is coupled to the printed circuit board  101  by a fixture  104 . As shown in FIG. 2, the fixture  104  includes a fixing board  105  coupled to the optical adapter  102 , and a base  106  coupled to the printed circuit board  101 . The fixing board  105  swings in the direction perpendicular to the print circuit board  101  on the axis  107 . The swing of the fixing board  105  allows the optical adapter  102  and the printed circuit board  101  apart, and facilitates the connection of the optical adapter  102  and the optical fiber cable  103 .  
           [0006]    Japanese Laid Open Utility Model Application (JU-A-Heisei 2-78903) discloses another optical adapter installation structure. A plurality of fixing members are provided in the structure, each of which is coupled to an optical adapter. When an operator connects optical fiber cables to the optical adapters, the fixing members are separately rotated toward the operator. The rotation of fixing members facilitates the connection by the operator.  
           [0007]    Other optical adapter installation structures are disclosed in Japanese Patent Office Gazette (Jp-B 2505865 and Jp-B 2988203). In these structures, an optical adapter is coupled to a printed circuit board by a fixture. The fixture allows the optical adapter to be drawn outside the printed circuit board, and facilitates the connection of the optical adapter to an optical fiber cable.  
           [0008]    Also, still another optical adapter installation structure is disclosed in Japanese Laid Open Patent Application (Jp-A-Heisei 9-178998). In this structure, an optical adapter is installed in a tray. The tray is rotatably fixed on an axis. The tray is rotated to be drawn out of a housing to facilitate the connection of the optical adapter to an optical fiber cable.  
           [0009]    Yet still another optical adapter mounting structure is disclosed in Japanese Patent Office Gazette (Jp-B 2891925). In the structure, optical adapters are fixed to a board having a notch. The optical adapters are located besides the notch. The notch provides a space for connection of optical fibers to the optical adapters, which facilitates the connection.  
           [0010]    When an optical adapter is provided on a board, the optical adapter is preferably close to the edge of the board for facilitating the connection of an optical adapter and an optical fiber cable. However, this enlarges protrusion of the optical fiber cable from the edge of the board.  
           [0011]    If the optical adapter is fixed away from the edge of the board, the protrusion of the optical fiber cable from the edge of the board is reduced. However, the easiness of the handle of the optical fiber cable and the optical adapter is also reduced.  
         SUMMARY OF THE INVENTION  
         [0012]    Therefore, an object of the present invention is to provide an optical adapter mounting structure for reducing protrusion of the optical fiber from an edge of a board on which optical adapter is mounted.  
           [0013]    Another object of the present invention is to provide an optical adapter mounting structure for facilitating connection of an optical adapter and an optical fiber cable.  
           [0014]    Still another object of the present invention is to provide an optical adapter mount structure for reducing vibration of an inner optical fiber cable provided above a board.  
           [0015]    In order to achieve an aspect of the present invention, an optical circuit assembly is composed of a board for mounting an optical circuit element, an optical adapter that connects an optical fiber cable to the optical circuit element, and an adapter supporting member which movably supports the optical adapter. The adapter supporting member allows the optical adapter to move between first and second positions. The first position is located substantially at an edge of the board, and the second position is located above the board away from the edge.  
           [0016]    The adapter supporting member preferably includes a grip for handling by an operator to move the optical adapter.  
           [0017]    The adapter supporting member preferably includes a first fixing member which locks the optical adapter to the first position.  
           [0018]    In this case, it is preferable that the adapter supporting member preferably further includes a grip for handling by an operator to move the optical adapter, and the first fixing member releases the optical adapter from the first position by the handling.  
           [0019]    The adapter supporting member preferably includes a second fixing member which locks the optical adapter to the second position.  
           [0020]    In this case, it is preferable that the adapter supporting member further includes a grip for handling by an operator to move the optical adapter, and the second fixing member releases the optical adapter from the second position by the handling.  
           [0021]    Preferably, the adapter supporting member further includes a sliding piece, and the second fixing member releases the optical adapter from the second position in response to sliding of the sliding piece.  
           [0022]    The sliding piece is preferably located substantially at the edge.  
           [0023]    The adapter supporting member preferably includes a swinging bar coupled to the optical adapter, and an axis which is connected to one of ends of the swinging bar to allow the supporting bar to swing on the axis.  
           [0024]    The adapter supporting member preferably includes an adapter carrier coupled to the optical adapter, an adapter guide member slidingly connected to the adapter carrier to guide the adapter carrier such that the optical adapter moves between the first and second positions.  
           [0025]    The optical circuit assembly may be further composed of an optical fiber guide member connected on the board. In this case, the optical circuit element includes an inner optical fiber cable coupled to the optical adapter, and the optical fiber guide member guides the inner optical fiber cable to move substantially in an plane.  
           [0026]    In this case, the optical fiber guide member is preferably composed of first and second planar boards, and the inner optical fiber cable passed between the first and second planar boards.  
           [0027]    The optical circuit assembly may be further composed of a fiber supporting member connected on the board, and the optical circuit element may includes an optical device, and an inner optical fiber cable connected between the optical device and the optical adapter. Also, the adapter supporting member may be provided on a first side of the board, and the optical device may be provided on a second side of the board opposite to the first side, and the board may be provided with a hole between the first and second side. In this case, the fiber supporting member preferably supports the inner optical fiber cable such that the inner optical fiber cable passes through the hole.  
           [0028]    The fiber supporting member preferably includes a tube surrounding the inner optical fiber cable to protect the inner optical fiber cable.  
           [0029]    The fiber supporting member preferably supports the inner optical fiber cable such that a first portion of the inner optical fiber cable located on the first side moves by a movement of the optical adapter while a second portion of the inner optical fiber cable located on the second side stays substantially in the same place. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0030]    [0030]FIG. 1 shows a conventional optical adapter mounting structure;  
         [0031]    [0031]FIG. 2 shows the fixture  104  of the conventional optical adapter mounting structure;  
         [0032]    [0032]FIG. 3 shows a first embodiment of the optical circuit assembly according to the present invention;  
         [0033]    [0033]FIG. 4 shows a rotating mechanism  50 ;  
         [0034]    [0034]FIGS. 5A and 5B show the rotating mechanism  50 ;  
         [0035]    [0035]FIG. 6 shows the rotating mechanism  50  with a lock lever  8  locked by a guide piece  10 ;  
         [0036]    [0036]FIG. 7 shows the swing of the lock lever  8  for withdrawing an optical adapter  1  and an optical fiber cable  4 ;  
         [0037]    [0037]FIG. 8 shows the swing of the lock lever  8  for withdrawing the optical adapter  1  and the optical fiber cable  4 ;  
         [0038]    [0038]FIG. 9 shows the rotating mechanism  50  with the lock lever  8  locked by a lock plate  9 ;  
         [0039]    [0039]FIG. 10 shows a fiber holder  14  and plates  15 ,  16 , and  17 ;  
         [0040]    [0040]FIGS. 11A and 11B show the fiber holder  14  in detail;  
         [0041]    [0041]FIG. 12 shows the plates  15 ,  16 , and  17 .  
         [0042]    [0042]FIG. 13 shows the movement of inner optical fiber cables  7  in response to the rotation of lock lever  8 ;  
         [0043]    [0043]FIG. 14 shows a rotating mechanism  60  in a second embodiment;  
         [0044]    [0044]FIG. 15 shows the rotating mechanism  60 ;  
         [0045]    [0045]FIG. 16 shows a sliding mechanisms  90  in a third embodiment; and  
         [0046]    [0046]FIG. 17 shows the sliding mechanism  90 . 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0047]    Embodiments of an optical circuit assembly according to the present invention will be described below with reference to the attached drawings.  
       First Embodiment  
       [0048]    In a first embodiment of the optical circuit assembly according to the present invention, a mother board is provided with optical adapters. As shown in FIG. 3, the optical adapters  1  are coupled to the mother board  2   a . The optical adapters  1  are connected to optical fiber cables  4  for transfer optical signals between the optical circuit assembly and another optical processing unit.  
         [0049]    A daughter board  2   b  is coupled to the mother board  2   a  on the opposite side to the optical adapters  1 . Optical modules  3  are provided on the daughter board  2   b  for optical and electronic processing. The mother board  2   a  has an aperture  20 , and the optical modules  3  are connected to the optical adapters  1  by inner optical fiber cables  7  passing through the aperture  20 . Attenuators  18  are inserted between the optical adapters  1  and the inner optical fiber cables  7  to attenuate optical signals.  
         [0050]    The optical adapters  1  are connected to the mother board  2   a  by rotating mechanisms  50 . The rotating mechanisms  50  are screwed onto the mother board  2  to rotatably support the optical adapters  1 .  
         [0051]    [0051]FIG. 4 shows rotating mechanisms  50 . Each of the rotating mechanisms  50  includes a lock lever  8 , lock plate  9 , a guide piece  10  and a spring pin  11 . The lock lever  8  is coupled to the optical adapter  1 . The lock lever  8  is rotatably supported by the guide piece  10 , and allowed to swing on the spring pin  11  in a direction parallel to the mother board  2   a.    
         [0052]    The lock lever  8  includes a swinging bar  8   a , a protrusion  8   b  and a stopper  8   c  and a grip  8   d . The swinging bar  8   a  has a hole (not shown) through which the optical adapter  1  is inserted in a direction vertical to the swinging bar  8   a . The protrusion  8   b  and the stopper  8   c  are disposed at one end of the swinging bar  8   a . Both of the protrusion  8   b  and the stopper  8   c  protrude in the direction in which the swinging bar  8   a  extends. The grip  8   d  is vertically connected to the other end of the swinging bar  8   a . The grip  8   d  is used for handling of the optical adapter  1  by a user of the optical circuit assembly. A slit is preferably provided on the grip  8   d  for an easy pinch of the grip  8   d.    
         [0053]    The swinging bar  8   a  has a hole  8 e through which the spring pin  11  is passed. The spring pin  11  is fixed to the guide piece  10 , and the swinging bar  8   a  is rotatably supported by the guide piece  10  on the spring pin  11 . The hole  8 e has short and long axes orthogonal to each other. The long axis is parallel to the direction in which the swing bar  8   a  extends. The length of the long axis is longer than the protruding length of the protrusion  8   b.    
         [0054]    As shown in FIG. 5A and 5B, the swinging bar  8   a  can be accommodated in the guide piece  10 . As shown in FIG. 4, a block  10   a  is provided in the guide piece  10 . A crow  10   c  is formed on the block  10   a . In addition, a shaft  12   a  and a coil spring  13  are provided in the guide piece  10 . The shaft  12  is passed through the coil spring  13 . The coil spring  13  pushes the lock lever  8  toward the crow  10   c.    
         [0055]    The crow  10   c  is engaged to the protrusion  8   b  and the stopper  8   c  to lock the swinging bar  8   a  when the swinging bar  8   a  is accommodated in the guide piece  10 . The coil spring  13  pushes the lock lever  8  toward the crow  10   c  to tightly fix the lock lever  8 .  
         [0056]    The swinging bar  8   a  can be locked by the lock plate  9  at an angle of  45  degrees to the guide piece  10 . The lock plate  9  includes a plate body  9   a , a plate spring  9   b , and a wall  9   d . The plate body  9   a  is screwed to the mother board  2   a  to be disposed at an angle of  45  degrees to the guide piece  10 . The plate spring  9   b  is coupled to the plate body  9   a . The plate spring  9   b  is allowed to swing beside the plate body  9   a . One end of the plate body  9   a  away from the guide piece  10  is coupled to the wall  9   d . The plate spring  9   b  and the wall  9   d  are engaged to the protrusion  8   b  to lock the swinging bar  8   a  at an angle of  45  degrees to the guide piece  10 .  
         [0057]    When the optical processing is executed by the optical module assembly, the optical adapters  1  and the optical fiber cables  4  are withdraw to reduce the protrusion of the optic fiber cables  4 . The lock levers  8  are swung to withdraw the optical adapters  1  and the optical fiber cables  4 . The operation of the rotating mechanism  50  for withdrawing the optical adapter  1  optic and fiber cables  4  is described below.  
         [0058]    Suppose that the swinging bar  8   a  is accommodated in the guide piece  10  as shown in FIG. 6. At this time, the optical adapter  1  is located substantially at the edge of the mother board  2   a . An operator lifts up the lock lever  8  on the grip  8   d  against the pushing force of the coil spring  13   a  to release the swinging bar  8   a  from the crow  10   c  of the block  10   a . The lifting of the lock lever  8  allows the swinging bar  8   a  to swing. Next, the user pushes the grip  8   d  in an obliquely downward direction to swing the lock lever  8  as shown in FIG. 7.  
         [0059]    As shown in FIG. 8, the swinging of the lock lever  8  by the operator deforms the plate spring  9   b  and contracts the coil spring  13 . The deformed plate spring  9   b  returns back to the original state when the lock lever  8  is rotated at the angle of 45 degrees to the guide piece  10 . Then, the plate spring  9   b  and the stopper  8   c  of the supporter  8   a  are engaged to lock the lock lever  8 . The wall  9   d  of the lock plate  9  protects the lock lever  8  from being excessively rotated in the depth direction.  
         [0060]    When the optical fiber cables  4  are connected or disconnected to the optical adapters  1 , the optical adapters  1  are accommodated in the guide pieces  10  and placed at the edge of the mother board  2   a . The operation of the rotating mechanism  50  for placing the optical adapter  1  at the edge of the mother board  2   a  is described below.  
         [0061]    Suppose that the lock lever  8  is engaged to the lock plate  9  as shown in FIG. 9. The operator picks up the grip  8   d  of the lock lever  8  and then lifts up the grip  8   d  against the pushing force in a direction vertical to the plate spring  9   b . The lift of the lock lever  8  releases the stopper  8   c  from the spring plate  9   b . So, the operator, while lifting up the grip  8   d , swings the lock lever  8  to accommodate the swinging bar  8   b  in the guide piece  10 , then takes the grip  8   d  down. The protrusion  8   b  of the lock lever  8  is engaged to the crow  10   c  of the block  10   a  to lock the lock lever  8  to the guide piece  10 .  
         [0062]    The above-mentioned operations can be executing by using only the lever, which makes the operations easier.  
         [0063]    With reference to FIG. 3, the inner optical fiber cables  7  are moved and flickered by the swing of the lock levers  8  connected to the optical adapters  1 . The flicker of the inner optical fiber cables  7  may damage the inner optical fiber cables  7  through contact with other components provided in the optical circuit assembly.  
         [0064]    A fiber holder  14 , rectangular plates  15 ,  16 , and  17  are provided on the mother board  2   a  to guide the inner optical fiber cables  7 , preventing the inner optical fiber cables  7  from being applied with a mechanical force by a contact with other components. As shown in FIG. 10, the inner optical fiber cables  7 , which are connected between the optical modules  3  and the optical adapters  1 , are supported by the fiber holder  14 , and the plates  15 ,  16 , and  17 . The fiber holder  14  clamps the inner optical fiber cables  7 , and thereby the first portion of the inner optical fiber cables  7  between the optical modules  3  and the fiber holder  14  stands still without moving when the lock levers  8  are swung.  
         [0065]    [0065]FIG. 11A shows a front view of the fiber holder  14  viewed from direction vertical to the mother board  2   a , and FIG. 11B shows a side view of the fiber holder  14  viewed from a direction of the arrow C in FIG. 11A.  
         [0066]    The fiber holder  14  includes a holder body  14   a  and a clamp  14   b . The holder body  14   a  is fixed on the mother board  2   a . The clamp  14   b  is coupled to the holder body  14   b  and clamps the inner optical fiber cables  7 . Each of the inner optical fiber cables  7  are wrapped by a silicone tube  19  in the clamped portion thereof. A spiral notch is made in the silicon tube  19 . The soft silicone tube  19   b  protects the optical fiber cable  7 . Also, the silicone tube  19  increases the curvature radius of the optical fiber  7 , which is introduced between the surface  23   a  on which the rotating mechanisms  50  are provided and the surface  23   b  facing the daughter board  2   b.    
         [0067]    The second portion of the inner optical fiber cables  7  between the fiber holder  14  and the optical adapters  1  moves in response to the swing of the lock levers  8 . The plates  15 ,  16 , and  17  guide the second portion for avoiding the damage thereof.  
         [0068]    [0068]FIG. 12 shows the plates  15 ,  16 , and  17 . Gaps are respectively provided between the plate  15  and the plate  16  and between the plate  16  and the plate  17 . As shown in FIG. 3, the inner optical fiber cables  7  are introduced across the edge  24   a  and  24   b  and passed through the gaps to be guided in the same direction when moved by the rotating mechanism  50 . The plates  15 ,  16  and  17  have screw holes (not shown) in the corners  27   a ,  27   b ,  27   c  and  27   d . As shown in FIG. 12, supporters  22  are placed on the mother board  2   a , and the plates  15 ,  16  and  17  and the supporters  22  are screwed to the mother board  2   a  by screws  21   a , the supporters  22  being inserted between the plate  15  and the mother board  2   a.    
         [0069]    Shims  25   a  to  25   d  and  26   a  to  26   d  are provided for regulating the movement route of the inner optical fiber cables  7 . As shown in FIG. 12, the shims  25   a ,  25   b ,  25   c  and  25   d  are inserted between the plate  15  and  16 . The shims  26   a ,  26   b ,  26   c  and  26   d  are inserted between the plate  16  and  17 . The shims  25   a  to  25   d  and  26   a  to  26   d  are screwed to the mother board  2   a  and the plates  15 ,  16  and  17  by the above-mentioned screws  21   a . The shims  25   a  to  25   d  and  26   a  to  26   d  prevent the inner optical fiber cables  7  from being contacted with the screws  21   a . As shown in FIG. 3, the shims  25   a  to  25   d  and  26   a  to  26   d  are sectoral, and the sectoral shape of them increases a curvature radius of the inner optical fiber cables  7 .  
         [0070]    The shim  25   a  is located in the corner  27   a , which is formed between the edges  24   a  and  24   b . The shim  25   b  is located in the corner  27   b , which is formed on the other end of the edge  24   b . The shim  25   c  is located in the corner  27   c , which is formed on the other end of the edge  24   a . The shim  25   d  is located in the remaining corner  27   d  of the plate  15 . The radiuses of the shims  25   a  and  25   b  are larger than those of the shims  25   c  and  25   d.    
         [0071]    The shims  26   a ,  26   b ,  26   c , and  26   d  are respectively located in the corner  27   a ,  27   b ,  27   c ,  27   d.    
         [0072]    [0072]FIG. 13 shows the movement of the inner optical fiber cables  7  when the lock lever  8  is swung to withdraw the optical adapters  1  and the optical fiber cables  4 . The plates  15 ,  16  and  17  guide the inner optical fiber cables  7  in the same direction when the inner optical fiber cables  7  are moved by the rotating mechanisms  50 . Each of the inner optical fiber cables  7  are guided by the plates  15 ,  16  and  17  to move substantially in a plane parallel to the plates  15 ,  16 , and  17 . Also, the plates  15 ,  16  and  17  suppress the suspension of the inner optical fiber cables  7 , and protect the interference with the components on the mother board  3 . This suppresses the load applied to the inner optical fiber cables  7  and prevents the inner optical fiber cables  7  from being damaged.  
         [0073]    In the first embodiment, the optical adapter  1  is rotated and fixed above the mother board  2   a , and the protrusion of the optical fiber cables  4  from the edge of the mother board  2   a  is reduced when the optical circuit assembly is in service.  
         [0074]    In addition, the flicker of the inner optical fiber cables  7  during the shipment or the service is suppressed by the fiber holder  14  and the plates  15 ,  16 , and  17 .  
         [0075]    Furthermore, the rotating mechanisms  50  facilitate the connection and disconnection of the optical adapters  1  and the optical fiber cables  4 .  
       Second Embodiment  
       [0076]    In the second embodiment, the rotating mechanisms  50  in the first embodiment are replaced by rotating mechanisms  60  shown in FIG. 14. Except for the rotating mechanisms  60 , the configuration of the optical circuit assembly in the second embodiment is identical to that in the first embodiment.  
         [0077]    In the rotational mechanism  60 , the guide piece  10  and the lock plate  9  in the rotational mechanism  50  are respectively replaced by a lock piece  29  and a guide piece  30 . In addition, a hook lever  31  and a package front plate  32  are attached in front of the guide piece  30 .  
         [0078]    As shown in FIG. 15, the swinging bar  8   a  is accommodated in the guide piece  30  when swung to the edge of the mother board  2   a . As shown in FIG. 14, the guide piece  30  includes a block  30   a , a shaft  12 , and a coil spring  13 . A crow  30   c  is provided on the block  30   a  to be engaged to the protrusion  8   b  and the stopper  8   c  to lock the lock lever  8 . The coil spring  13  pushes the lock lever  8  by the shaft  12 . The spring pin  11 , which rotatably supports the lock lever  8 , is connected to the upper portion of the guide piece  30 .  
         [0079]    The lock plate  29  is composed of a plate body  29   a  disposed at an angle of 45 degrees to the guide piece  30 , a plate spring  29   b  in parallel along the plate body  29   a , and a hook lever  31 . The plate body  29   a  is screwed to the mother board  2   a . The plate body  29   a  has a wall  29   d  on the tip thereof. The plate spring  29   b  and the wall  29   d  are engaged to the swinging bar  8   a  on the stopper  8   c  such that the swinging bar  8   a  is locked at an angle of 45 degrees to the guide piece  30 .  
         [0080]    The hook lever  31  is composed of a lever  31   a , a hook lever body  31   b , a shaft  12   b , and a coil spring  13   b . The lever  31   a  is disposed in front of the package front plate  32 , and located substantially at the edge of the mother board  2   a . The lever  31   a  is allowed to slide on the package front plate  32  in the vertical direction. The hook lever body  31   b  is connected between the lever  31   a  and the plate spring  29   b . The hook lever body  31   b  and the plate spring  29   b  are shifted in response to the slide of the lever  31   a . The hook lever body  31   b  is coupled to the shaft  12   b . The shaft  12   b  penetrates the guide piece  30 , and supported by the coil spring  13   b . The coil spring pushes the hook lever body  31   b  by the shaft  12   b.    
         [0081]    When the lock lever  8  is accommodated in the guide piece  30 , the protrusion  8   b  is engaged to the crow  30   c  to lock the lock lever  8 . When engaged to the crow  30   c , the lock lever  8  is downwardly pushed by the coil spring  13   a  so that the lock of the lock lever  8  is not released.  
         [0082]    When the lock lever  8  is kept at the angle of 45 degrees to the guide piece  10 , the stopper  8   c  is engaged to the wall  29   d  and the plate spring  29   b . The wall  29   d , if the lock lever  8  is reclined at an angle of 45 degrees or more, collides with the stopper  8   c  to accordingly stop the rotation.  
         [0083]    A slide of the lever  31   a  by an operator releases the lock of the lock lever  8  from the lock plate  29 . When the lock lever  8  is locked by the lock plate  29 , the coil spring  13   a  pushes the lock lever  8  toward the lock plate  29  to keep the lock of the lock lever  8 . The downward slide of the lever  31   a  detaches the plate spring  29   b  from the lock lever  8  to release the lock of the lock lever  8 . Then the lock lever  8  is allowed to swing.  
         [0084]    The operator swings the lock lover  8  by the grip  8   d  to accommodate the swinging bar  8   a  in the guide piece  30 . The downward shift of the grip  8   d  by the operator engages the lock lever  8  and the guide piece  30  to lock the lock lever  8 .  
         [0085]    In the second embodiment, the hook lever  31  facilitates the release of the lock lever  8  from the lock plate  29 .  
       Third Embodiment  
       [0086]    In the third embodiment, the rotating mechanisms  50  in the first embodiment are replaced by sliding mechanisms  90  shown in FIG. 16. Except for the sliding mechanisms  90 , the configuration of the optical circuit assembly in the third embodiment is identical to that in the first embodiment.  
         [0087]    [0087]FIG. 16 is a side sectional view showing the sliding mechanisms  90 . FIG. 17 is a front view when the sliding mechanism  90  is viewed from a direction of an arrow E.  
         [0088]    As shown in FIG. 16, each of the sliding mechanisms  90  includes a lock lever  78  and spring pin  71  and a guide piece  80 . The lock lever  78  is coupled to the optical adapter  1 , which connects the optical fiber cable  4  and the inner optical fiber cable  7 . The attenuator  18  is inserted between the optical adapter  1  and the inner optical fiber cable  7 . The spring pin  71  is fixed to the upper portion of the guide piece  80 . The lock lever  78  is slidingly coupled to guide piece  80  on the spring pin  71 .  
         [0089]    The lock lever  78  is composed of a supporter  78   a , a wheel  78   b , a wheel shaft  78   c  and a grip  78   d . The supporter  78   a  is coupled to the optical adapter  1 . A hole (not shown) is made in the supporter  78   a , in order to insert the optical adapter  1  in a direction vertical to the supporter  78   a.    
         [0090]    The wheel  78   b  is connected by the wheel shaft  73   c  to a tip of the supporter  78   a . The grip  78   d  vertically is coupled to the other tip of the supporter  78   a . A U-shaped long hole  78   e  is provided through the grip  78   d . The spring pin  71  is inserted through the U-shaped long hole  78   e . The U-shaped long hole  78   e  includes a sliding portion  78   e   1 , locking portions  78   e   2  and  78   e   3 . The sliding portion  78   e   1  extends in the direction parallel to the extension direction of the grip  78   d . The locking portions  78   e   2  and  78   e   3  are provided at the both ends of the sliding portion  78   e   1 , and extend in the direction orthogonal to the sliding portion  78   e   1 . The locking portions  78   e   2  and  78   e   3  have a length longer than the radius of the wheel  78   b.    
         [0091]    The grip  78   d  is handled by an operator to slide the lock lever  78 . A slit is made in the grip  78   d  for an easy pinch of the grip  78   d.    
         [0092]    As shown in FIG. 17, The lock lever  78  is accommodated in the guide piece  80 . The guide piece  80  is composed of a plate  80   c , walls  80   d ,  80   e  and  80   f . The plate  80   c  horizontally guides the lock lever  78 . The walls  80   d ,  80   e  and  80   f  stop the horizontal movement of the lock lever  78 . A groove  80   a  disposed between the wall  80   d  and the plate  80   c ; and a groove  80   b  disposed between the wall  80   f  and the plate  80   c . The grooves  80   a  and  80   b  accommodate the wheel  78   b  to lock the lock lever  78 .  
         [0093]    When the optical circuit assembly is in service, the optical adapters  1  and the optical fiber cables  4  are withdrawn to the inside of the mother board  2   a . To withdraw the optical adapters  1  and the optical fiber cables  4 , the lock lever  78  is pushed away from the edge of the mother board  2   a . In detail, the operator lifts up the grip  8   d  along the locking portion  78   e   3  to release the lock of the lock lever  78  from the groove  80   b . The lock lever  78  is allowed to slide in the horizontal direction. Next, the operator pushes and slides the lock lever  78  by the grip  78   d . During the slide of the lock lever  78 , the wheel  78   b  is rolled on the plate  80   c  to guide the lock lever  78  in the horizontal direction. Then, the wheel  78   b  drops onto the groove  80   a  from the plate  80   c , and collides with the walls  80   d ,  80   e  to lock the lock lever  78 . The walls  80   d ,  80   e  protect the lock lever  78  from being excessively moved in the horizontal direction.  
         [0094]    To connect or disconnect the optical fiber cable  4  to the optical adapter  1 , The optical adapter  1  is drawn to the edge of the mother board  2   a . To draw the optical adapter  1 , the lock lever  78  is pulled to the edge of the mother board  2   a . In detail, the operator lifts up the grip  8   d  along the locking portion  78   e   2  to release the lock of the lock lever  78  from the groove  80   a . The lock lever  78  is allowed to slide in the horizontal direction. Next, the operator pulls and slides the lock lever  78  by the grip  78   d . During the slide of the lock lever  78 , the wheel  78   b  is rolled on the plate  80   c  to guide the lock lever  78  in the horizontal direction. Then, the wheel  78   b  drops onto the groove  80   b  from the plate  80   c , and collides with the walls  80   f  to lock the lock lever  78 . The wall  80   f  protects the lock lever  78  from being excessively moved in the horizontal direction.  
         [0095]    As mentioned above the sliding mechanisms  90  facilitate the connection and disconnection of the optical adapters  1  and the optical fiber cables  4 .  
         [0096]    Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been changed in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of the invention as hereinafter claimed.