Patent Publication Number: US-2012033922-A1

Title: Optical connector, removal tool, and optical connector-removing structure

Description:
TECHNICAL FIELD 
     The present invention relates to an optical connector, a removal tool for removing the optical connector from an optical adapter, and an optical connector-removing structure including the same. 
     BACKGROUND ART 
     The optical connector is intended to be attached to ends of optical fiber cables and then attached to the optical adapter (or an optical receptacle, the same shall apply hereinafter), to thereby connect the optical fiber cable to another optical fiber cable or optical communication module so as to provide optical communication. 
     For example, in Patent Literature 1, there is disclosed an optical connector, which has a locking lever for preventing the connector from coming off from the optical adapter. The optical connector is configured to engage the locking lever with the optical adapter to prevent the connector from coming off from the optical adapter. Pressing down and resiliently deforming the locking lever results in disengagement of the locking lever from the optical adapter, and the optical connector is allowed to be removed from the optical adapter. 
     CITATION LIST 
     
         
         Patent Literature 1: Japanese Patent Application Laid-open No. 2009-109978 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     The optical connector as described above can be removed from the optical adapter by anyone pushing down the locking lever. However, in the case of the optical connector connected to a server, for example, security problems may arise if it is feasible for anyone to remove the optical connector. 
     An object to be achieved by the present invention is to allow the removal of the optical connector from the optical adapter only by predetermined manipulations, thereby improving security. 
     Solution to Problem 
     In order to achieve the above-mentioned object, the present invention provides an optical connector which includes: a ferrule attached to an end of an optical fiber; a housing for holding the ferrule; a locking lever having a locking portion which engage with an optical adapter, a front end fixed to a top surface of the housing, and a rear end capable of flexibly moving up and down; and a covering member having an holding portion which holds an entire outer periphery of the housing, a covering portion which covers top surface of the rear end of the locking lever, and a tool insertion hole which is provided between the holding portion and the covering portion so as to extend through the covering member in an optical axis direction. 
     Here, the “optical axis direction” refers to the direction in which the optical fiber extends (left-right direction of  FIG. 2 ), an end side of the optical fiber in the optical axis direction (right side of  FIG. 2 ) is referred to as “front” and the opposite side thereof (left side of  FIG. 2 ) is referred to as “rear”. Further, one direction orthogonal to the optical axis direction is described as an up-down direction. However, this is defined for convenience of illustrating relative positional relationships among each of the components and not intended to limit use aspects of the optical connector. 
     In this way, the top surface of the rear end of the locking lever is covered by the covering portion, and hence the locking lever cannot be pressed from above. With this configuration, the removal of the optical connector from the optical adapter is restricted and security of an equipment connected to the optical connector (for example, a server) can be improved. The removal of the optical connector from the optical adapter is achieved by inserting the removal tool into the tool insertion hole of the covering member from the rear side of the connector and pushing down the rear end of the locking lever positioned under the covering portion. 
     In the optical connector as described above, if the covering portion deforms easily, there is a risk that the covering portion is pressed from above to deform, and the covering portion thus deformed in turn pushes down the locking lever, thereby causing the removal of the optical connector from the optical adapter. Thus, under a state in which the optical connector is attached to the optical adapter, if the covering portion extends to a position to partially cover a top surface of the optical adapter, even when the covering portion is pressed from above, the covering portion can abut the top surface of the optical adapter to restrict the deformation of the covering portion, to thereby reliably prevent the locking lever to be pushed down. 
     In addition, the optical adapter may have an engagement hole formed through the top surface thereof for engaging with the locking lever of the optical connector. If the locking lever is manipulated through this hole, there is a risk that the optical connector is removed from the optical adapter. Thus, under a state in which the optical connector is attached to the optical adapter, if the covering portion covers the engagement hole of the optical adapter, it is possible to prevent the locking lever from being manipulated through the engagement hole. 
     In the optical connector described above, the holding portion provided in the covering member has a cylindrical shape to hold the entire outer periphery of the housing. Therefore, assembly of the covering member and the housing is achieved, for example, by covering the holding portion over the housing from the rear side thereof. At this point, if the ferrule and the optical fiber cable have been already assembled to the housing, the optical fiber cable hinder the covering member from being assembled onto the housing from the rear side thereof. Thus, the holding portion of the covering member is configured to include an upper holding part which holds the top surface of the housing and a lower holding part which holds bottom surface of the housing. As a result, even when the ferrule and the optical fiber cable have been already assembled onto the housing, it is possible to assemble the upper holding part and the lower holding part in such a manner that the upper holding part and the lower holding part clamp the optical fiber cable from above and below, house the optical fiber cable within an inner periphery of the holding portion, and subsequently assemble the covering member onto the housing from the rear side thereof. 
     The optical connector described above can be removed from the optical adopter using a removal tool which includes an operation lever having a front end capable of flexibly moving up and down. Under a state in which the operation lever is inserted into the tool insertion hole from the rear side thereof, the front end of the operation lever is positioned above the rear end of the locking lever, and the rear end of the operation lever projects rearward from the tool insertion hole. Specifically, under the state in which the operation lever of the removal tool is inserted into the tool insertion hole from the rear side thereof, it is possible to press the rear end of the operation lever projecting rearward from the tool insertion hole from above to cause the front end of the operation lever to be pushed down, thereby pushing down the rear end of the locking lever. As a result, the locking lever of the optical connector is disengaged from the optical adapter, and the optical connector can be removed from the optical adapter. 
     If it is possible to remove all optical connectors by one kind of removal tool, any optical connector can be removed as long as the removal tool is available, and thus security may not necessarily be sufficient. Thus, according to an optical connector-removing structure according to the invention, a recessed portion (or a projecting portion) is provided in the top surface of the operation lever, and correspondingly a projecting portion (or a recessed portion) is provided in the tool insertion hole of the covering member of the optical connector. If the recessed portion of the operation lever fit with the projecting portion of the tool insertion hole, the front end of the operation lever inserted into the tool insertion hole is positioned above the rear end of the locking lever. In this case, it is possible to push down the operation lever to cause the locking lever to be pushed down, to thereby remove the optical connector from the optical adapter. On the other hand, if the recessed portion of the operation lever does not fit with the projecting portion of the tool insertion hole, the operation lever inserted into the tool insertion hole is pushed down by the projecting portion of the tool insertion hole, so that the front end of the operation lever cannot be positioned above the rear end of the locking lever. In this case, pushing down the operation lever does not cause the locking lever to be pushed down, and thus the optical connector cannot be removed from the optical adapter. Therefore, according to the optical connector-removing structure described above, only a specific removal tool which is adapted to the optical connector can be used for removing the optical connector from the optical adapter, thereby further improving security. 
     Advantageous Effects of Invention 
     As described above, according to the present invention, in order to remove the optical connector from the optical adapter, it is required to provide an operation to insert the removal tool into the tool insertion hole of the covering member and push down the locking levers. As a result, it is possible to more reliably prevent the optical connector to be removed by an unauthorized person and improve security. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates a perspective view of the optical connector according to an embodiment of the present invention. 
         FIG. 2  illustrates a side view of the optical connector. 
         FIG. 3  illustrates a front view of the optical connector. 
         FIG. 4  illustrates a partial cross-sectional view of the optical connector. 
         FIG. 5  illustrates a perspective view of the covering member of the optical connector. 
         FIG. 6  illustrates a front view of the covering member. 
         FIG. 7A  illustrates a perspective view of one of the steps of assembling the covering member of the optical connector. 
         FIG. 7B  illustrates a perspective view of one of the steps of assembling the covering member of the optical connector. 
         FIG. 8  illustrates a perspective view of the removal tool adapted to the optical connector. 
         FIG. 9  illustrates a partial cross-sectional view of one of the steps of removing the optical connector from the optical adapter using the removal tool. 
         FIG. 10  illustrates a partial cross-sectional view of one of the steps of removing the optical connector from the optical adapter using the removal tool. 
         FIG. 11  illustrates a partial cross-sectional view of one of the steps removing the optical connector from the optical adapter using the removal tool. 
         FIG. 12  illustrates a partial cross-sectional view of one of the steps removing the optical connector from the optical adapter using the removal tool. 
         FIG. 13  illustrates a perspective view of the removal tool adapted to another optical connector. 
         FIG. 14  illustrates a partial cross-sectional view of the removal tool in  FIG. 13  under a state of being attached to the optical connector in  FIG. 1 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     An embodiment of the present invention is now described with reference to the drawings. 
       FIGS. 1 to 3  illustrate an optical connector  1  according to an embodiment of the present invention. The optical connector  1  is a LC type optical connector, and attached to ends of optical fiber cables  3  each having an optical fiber (not shown) therein. The optical connector  1  mainly includes ferrules  10  each attached to a end of one of the optical fibers, housings  20  each holding one of the ferrules  10 , locking levers  30  each provided on a top surface of each of the housings  20 , a covering member  40  attached to a rear end of the housings  20 , and boots  50  each for protecting one of the optical fiber cables  3  which extend rearward from the housings  20 . The optical connector  1  according to this embodiment is a so-called duplex optical connector, in which a pair of housings  20  is integrated into the covering member  40 . Note that, an “up-down direction” refers to the height direction in  FIG. 2 , and a “width direction” refers to the direction orthogonal both to an optical axis direction and to the height direction (left-right direction in  FIG. 3 ). 
     Each of the ferrules  10  has a through-hole (not shown) which extends in the optical axis direction and through which the optical fiber is inserted. By attaching the optical connector  1  to the optical adapter  2  (shown as a dot-dash line in  FIG. 2 ), and causing each of the ends of the ferrules  10  to abut a corresponding one of the ends of the ferrules of a mating optical connector, the optical fibers are connected with each other so as to provide optical communication. 
     The housings  20  are, for example, formed of resin into a generally rectangular parallelepiped shape, which is adapted to be inserted into an attachment hole of the optical adapter  2 . Each of the housings  20  holds one of the ferrules  10  within its inner periphery, and the ends of the ferrules  10  project forward from the housings  20 . A spring (not shown) is provided inside each of the housings  20 , which springs maintain the ferrules  10  in a forwardly biased state. 
     Each of the locking levers  30  is connected to the top surface of each of the housings  20  on the front end and apart from the top surface of each of the housings  20  on the rear end. As a result, it is possible to flexibly move the rear ends  32  of the locking levers  30  (see  FIG. 2 ) up and down. In this embodiment, the locking levers  30  extend obliquely-upward and rearward from the top surfaces of the housings  20 , and the locking levers  30  and the housings  20  are integrally molded of resin. Each of the locking levers  30  has locking portions  31  provided in the middle in the optical axis direction and on both sides in the width direction. As illustrated in  FIG. 4 , the locking portions  31  of the locking levers  30  engage with engagement holes  2   a  provided in the optical adapter  2  in the optical axis direction, to thereby prevent the optical connector  1  from coming off from the optical adapter  2 . Flexibly pushing down the rear ends  32  of the locking levers  30  causes the locking portions  31  of the locking levers  30  to be disengaged from the engagement holes  2   a  of the optical adapter  2 . 
     As illustrated in  FIGS. 5 and 6 , the covering member  40  includes a holding portion  41  which holds the entire outer periphery of the housings  20 , a covering portion  42  which covers top surfaces of the locking levers  30 , and a tool insertion hole  43  which is provided between the holding portion  41  and the covering portion  42  so as to extend through the covering member  40  in the optical axis direction. 
     The holding portion  41  has a pair of holding holes  41   a  extending through the holding portion  41  in the optical axis direction. Inserting the rear ends of the housings  20  in these holding holes  41   a  allows the entire outer periphery of the rear ends of the housings  20  to be held by the holding portion  41 . Engagement protrusions  41   b  are formed on the inner peripheral surfaces of the holding holes  41   a . Specifically, each of a pair of holding holes  41   a  has two engagement protrusions  41   b  formed on both sides in the width direction of its inner wall. On the other hand, each of the housings  20  has two recessed portions  21  provided on both side surfaces in the width direction of the rear ends (see  FIG. 7A ). When the housings  20  are inserted into the holding holes  41   a  of the holding portion  41 , the engagement protrusions  41   b  of the holding portion  41  fit in the recessed portions of the housings  20  and the engagement protrusions  41   b  and the recessed portions engage with each other in the optical axis direction, to thereby prevent coming off of the housings  20  relative to the holding portion  41 . 
     As illustrated in  FIG. 6 , the holding portion  41  includes an upper holding part  44  and a lower holding part  45 . The upper holding part  44  has an top wall portion  44   a  which holds top surfaces of the housings  20 , a pair of outer wall portions  44   b  which hold side surfaces of the housings  20  on the outside in the width direction, and a central wall portion  44   c  which holds side surfaces of the housings  20  on the central side in the width direction. The lower holding part  45  has a bottom wall portion  45   a  which holds bottom surfaces of the housings  20  and a central wall portion  45   b  which holds sidewalls of the housings  20  on the central side in the width direction. Engagement of a locking claw  45   c  provided on the central wall portion  45   b  of the lower holding part  45  with a locking groove  44   d  provided on the central wall portion  44   c  of the upper holding part  44  causes the lower holding part  45  to be integrated with the upper holding part  44 . 
     The covering portion  42  is provided above the holding portion  41  via a covering sidewall portions  46  which extend upward from a top surface of the holding portion  41  on both ends in the width direction. In this embodiment, the covering portion  42 , the covering sidewall portions  46 , and the upper holding part  44  are integrally molded of resin. The covering portion  42  bridges top ends of the covering sidewall portion  46 , and extends forward to cover the top surfaces of the rear ends  32  of the locking levers  30  (see  FIG. 2 ). A projecting portion  47  is provided on an underside of the covering portion  42 . The projecting portion  47  has a different location and shape for each optical connector  1 , and in the illustrated example, the projecting portion  47  is formed at the center in the width direction of the covering portion  42  and extends in the optical axis direction. The projecting portion  47  has, on its rear end, an inclined surface which is inclined rearward and obliquely-upward. 
     As illustrated in  FIG. 6 , the tool insertion hole  43  includes a space defined by the covering portion  42 , the covering sidewall portions  46 , and the top wall portion  44   a  of the upper holding part  44 . In this embodiment, as viewed in the front view illustrated in  FIG. 3 , the rear ends  32  of a pair of the locking levers  30  are positioned within an inner periphery of the tool insertion hole  43 . 
     Assembly of the covering member  40  to the housings  20  is achieved in the following steps, for example. First, as illustrated in  FIG. 7A , the upper holding part  44  and the lower holding part  45  are assembled in such a manner that the upper holding part  44  and the lower holding part  45  clamp the optical fiber cables  3  from above and below, and the optical fiber cables  3  are positioned within the inner periphery of the holding holes  41   a . Subsequently, as illustrated in  FIG. 7B , the covering member  40  is moved forward, and the rear ends of the housings  20  are inserted into the holding holes  41   a  of the holding portion  41  of the covering member  40  from the front thereof. Then, the engagement protrusions  41   b  formed on the inner peripheral surfaces of holding holes  41   a  (see  FIG. 6 ) are engaged with the recessed portions  21  of the housings  20  ( FIG. 7A ), thereby securing the covering member  40  and the housings  20 . 
     As illustrated in  FIG. 2 , the rear ends  32  of the locking levers  30 , which project rearward from the optical adapter  2 , are covered by the above-located covering portion  42  of the covering member  40 , and hence the locking levers  30  cannot be pressed from above. As a result, the removal of the optical connector  1  from the optical adapter  2  can be restricted. In particular, a front end of the covering portion  42  extends to a position to partially cover the top surface of the optical adapter  2 . Therefore, even when the covering portion  42  is pressed from above, the covering portion  42  may abut the top surface of the optical adapter  2 , to thereby reliably prevent the covering portion  42  from downwardly deforming and pushing down the locking levers  30 . 
     Further, as illustrated in  FIG. 4 , the optical adapter  2  is formed with engagement holes  2   a , which engages with the locking portions  31  of the locking levers  30 . The engagement holes  2   a  are formed through the top surface of the optical adapter  2 , for convenience of molding. When an elongated needle-like tool or the like is inserted into the engagement holes  2   a  and pushes down the locking levers  30 , there is a risk that the locking portions  31  are disengaged from the engagement holes  2   a  and the optical connector  1  is removed from the optical adapter  2 . Therefore, as illustrated in  FIG. 4 , by extending the covering portion  42  to a position to cover the engagement holes  2   a  of the optical adapter  2 , it is possible to prevent the possibility of the engagement holes  2   a  being used to cause the removal of the optical connector  1 . 
     A removal tool  60  for removing the optical connector  1  from the optical adapter  2  is illustrated in  FIG. 8 . The removal tool  60  includes a base portion  61  and an operation lever  62  which extends forward from a top surface of the base portion  61 . The base portion  61  includes fitting portions  61   a  which fit around outer peripheral surfaces of the boots  50 . The fitting portions  61   a  are partial cylindrical surfaces which are open in the outside in the width direction, and covers an area equal to or larger than half the circumference of the outer peripheral surfaces of the boots  50 . When the fitting portions  61   a  fit around the outer peripheral surfaces of the boots  50 , the removal tool  60  is aligned relative to the optical connector  1  in a direction orthogonal to the optical axis direction. In particular, the optical connector  1  according to this embodiment is a duplex optical connector, so that fitting one fitting portion  61   a  around the two boots  50  respectively enables restriction of the rotation of the removal tool  60  around the boots  50 . 
     The operation lever  62  has a rear end connected to the base portion  61  and a front end  63  capable of flexibly moving up and down. Specifically, the operation lever  62  includes a inclined portion  62   a  extending obliquely-upward and forward from the top surface of the base portion  61 , a horizontal portion  62   b  extending horizontally forward from a leading edge of the inclined portion  62   a , and a reinforcing portion  62   c . The front end  63  of the horizontal portion  62   b  is capable of flexibly moving up and down. In this embodiment, the operation lever  62  is integrally formed of resin. The horizontal portion  62   b  is provided with a recessed portion which fits with the projecting portion  47  provided on a bottom surface of the covering portion  42 . In the illustrated example, a through-hole  62   d  extending up and down through the horizontal portion  62   b  is provided as the recessed portion. The through-hole  62   d  is provided at the center in the width direction of the horizontal portion  62   b  and has a rectangular shape extending in the optical axis direction. The reinforcing portion  62   c  is provided substantially parallel to the horizontal portion  62   b , has a rear end connected to the middle of the inclined portion  62   a , and has a front end connected close to the front end  63  of the horizontal portion  62   b . In this way, providing the operation lever  62  with the reinforcing portion  62   c  allows for increased strength and elastic restoring force when pushing down the operation lever  62 . 
     Hereinafter, steps of removing the optical connector  1  attached to the optical adapter  2  using the removal tool  60  is described. 
     First, two optical fiber cables  3  are fitted into the fitting portions  61   a  of the base portion  61  of the removal tool  60 . Next, the removal tool  60  is moved forward as illustrated in  FIG. 9  to position the front end  63  of the operation lever  62  to a rear opening of the tool insertion hole  43  of the covering member  40 . At this point, the base portion  61  of the removal tool  60  is in fitting relationship with two optical fiber cables  3 , so that the movement of the removal tool  60  in the direction orthogonal to the optical axis direction is restricted. The shape of the removal tool  60  is determined to enable the operation lever  62  to be inserted into a predetermined position (close to the top end) of the tool insertion hole  43  when the removal tool  60  is moved forward in this state. 
     When the removal tool  60  is pushed further forward, as illustrated in  FIG. 10 , the front end  63  of the operation lever  62  is flexibly pushed down by the projecting portion  47  of the covering portion  42 . In the course of this movement, the front end  63  of the operation lever  62  is guided along an inclined surface provided at the rear end of the projecting portion  47 , and thus smoothly pushed down. 
     When the removal tool  60  is further pushed forward, as illustrated in  FIG. 11 , the projecting portion  47  of the covering portion  42  is fitted into the through-hole  62   d  provided in the horizontal portion  62   b  of the operation lever  62 . At the same time, the operation lever  62  which has been pushed down by the projecting portion  47  flexibly returns to its original position, and the horizontal portion  62   b  of the operation lever  62  abuts or is brought into close proximity with the bottom surface of the covering portion  42 . Then, the base portion  61  of the removal tool  60  abuts the holding portion  41  of the covering member  40 , thereby completing the attachment of the removal tool  60  to the optical connector  1 . At this point, the front end  63  of the operation lever  62  is positioned above the rear ends  32  of the locking levers  30 . In addition, the rear end of the operation lever  62  projects rearward from the tool insertion hole  43  of the covering member  40 . In the illustrated example, more than half part of the operation lever  62  is exposed to the outside. 
     Next, as indicated by an arrow in  FIG. 12 , the part of the operation lever  62  of the removal tool  60  which is exposed to the outside is pushed down from above. As a result, the operation lever  62  is flexibly deformed to cause the front end  63  to be pushed down, and the front end  63  of the operation lever  62  in turn pushes down the rear ends  32  of the locking levers  30 . In this way, the locking portion  31  of the locking levers  30  is disengaged from the engagement hole  2   a  (see  FIG. 4 ) of the optical adapter  2 . Keeping this state and pulling the removal tool  60  and the optical connector  1  rearward allows the optical connector  1  to be removed from the optical adapter  2 . 
     The optical connector  1  and the removal tool  60  described above are configured to enable the projecting portion  47  provided on the covering portion  42  to fit into the recessed portion (through-hole  62   d ) provided on the operation lever  62 , to thereby position the rear ends  32  of the locking levers  30  above the front end  63  of the operation lever  62  (see  FIG. 11 ). On the contrary, if the projecting portion  47  of the covering portion  42  does not fit into the through-hole  62   d  of the operation lever  62 , the front end  63  of the operation lever  62  cannot be positioned above the rear ends  32  of the locking levers  30 . This configuration is described in detail below. 
     For example, the removal tool  60  illustrated in  FIG. 13  has through-holes  62   d  formed at two positions spaced from each other in the width direction of the horizontal portion  62   b  of the operation lever  62 . When the removal tool  60  is attached to the optical connector  1  described above, the projecting portion  47  and the through-holes  62   d  are not aligned with each other in the width direction, and thus the projecting portion  47  does not fit into the through-hole  62   d . Accordingly, as illustrated in  FIG. 14 , the operation lever  62  continues to advance forward under a state of being held down by the projecting portion  47 , the front end  63  of the operation lever  62  cannot be positioned above the rear ends  32  of the locking levers  30 . In the illustrated example, the front end  63  of the operation lever  62  abuts the rear ends  32  of the locking levers  30  from the rear side thereof. If the operation lever  62  is pushed down in this state, the rear ends  32  of the locking levers  30  cannot be pushed down. 
     In this way, if the position and size of the projecting portion  47  of the covering portion  42  do not match those of the through-hole  62   d  of the operation lever  62 , the optical connector  1  cannot be removed from the optical adapter  2  using the removal tool  60 . In other words, in case of the optical connectors  1  attached to a plurality of optical connection terminals (optical adapters) provided on a server or the like, providing a different position and size of the projecting portion  47  on the covering portion  42  for each of the optical connector  1  leads to the necessity of using the removal tool  60  which has the recessed portion (through-hole  62   d ) fittable with the projecting portion  47  of the optical connector  1  when the optical connector is removed. In this way, the removal tool  60  serves as a “key” adapted to each of the optical connector  1 , to thereby more reliably prevent the optical connector  1  to be removed by an unauthorized person and further improve security. 
     The present invention is not limited to the above-described embodiment. For example, although in the above-described embodiment the covering portion  42  is provided with the projecting portion  47  and the operation lever  62  is provided with the recessed portion (through-hole  62   d ), in contrast to this configuration, the covering portion  42  may be provided with the recessed portion and the operation lever  62  may be provided with the projecting portion. 
     In addition, although in the above-described embodiment the present invention is described as applied to the duplex optical connector  1 , the present invention is not limited to this type of optical connector and is applicable to a simplex optical connector, for example. 
     REFERENCE SIGNS LIST 
     
         
           1  optical connector 
           2  optical adapter 
           2   a  engagement hole 
           3  optical fiber cable 
           10  ferrule 
           20  housing 
           30  locking lever 
           31  locking portion 
           40  covering member 
           41  holding portion 
           42  covering portion 
           43  tool insertion hole 
           44  upper holding part 
           45  lower holding part 
           50  boot 
           60  removal tool 
           61  base portion 
           62  operation lever