Abstract:
A compact, highly compatible shading member-equipped optical connector plug that makes the optical connector plug compact while having the compatibility to engage existing connector receptacles. The shading member includes a shutter housing enclosing a plug frame slidably on an outside thereof, and inserted into an engagement opening of a connector receptacle to be engaged when the shading member-equipped optical connector is connected, a shutter one end of which is supported by the shutter housing at a front part of the housing and another end of which is urged by an elastic force and closes so as to shade the optical fibers at a position in front of the ferrule, and an elastic member disposed between the plug frame and the shutter housing that urges said shutter housing forward.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an optical connector plug that detachably connects with a connector receptacle or adapter in a connector for an optical cable, and more particularly, to a shading member-equipped optical connector plug provided with means to block light from an optical fiber cable. 
         [0003]    2. Related Art 
         [0004]    Conventionally, in optical communications, since the power of the light source increases as the optical communication volume increases, looking directly into an optical signal while connecting an optical connector can damage the eye. Further, in recent years, with the introduction of optical communications-based Internet in companies and homes, the opportunities for ordinary people other than specialists to come into contact with optical connector plugs has increased, and with it the danger of looking directly into an optical signal and suffering consequent eye damage. Moreover, it is also necessary to protect the end of an optical cable from contamination by dirt and the like. Consequently, a shutter has come to be provided on optical connector plugs as eye protection means as well as dust protection means. 
         [0005]    For example, in an optical connector described in JP-A-07-333454, a movable member is provided on an outer periphery of a connecting front surface side of an optical connector to which an optical cable is connected, and a cap member composed of a plurality of cap pieces is connected to a front surface side of the movable member by an opening/closing shaft. This opening/closing shaft is urged in a direction in which the cap pieces close, which enables the cap pieces to move in a direction of a diameter in conjunction with a sliding of the movable member with respect to the optical connector so as to open and close. 
         [0006]    In addition, an optical fiber connector described in JP-A-2005-092082 comprises a plug shutter unit, which in turn comprises a movable cylinder, a shutter door, and an engagement piece. The shutter door is opened and closed in accordance with the movement of the movable cylinder. The engagement piece engages an engagement hook on a connector receptacle side and the movable cylinder is moved together with the connector receptacle. Then, when the optical finer plug is drawn out from the connector receptacle, the movable cylinder is moved by itself and the shutter door is closed. 
         [0007]    However, in the invention described in JP-H07-333454-A, after the plug is engaged with the connector receptacle, even when such plug is removed the movable member does not automatically return to its original position, and therefore there is a risk that a worker might look directly into the light. Moreover, in the invention described in JP-A-2005-092082, although there is an automatic return means for the shutter, a specialized engagement piece is used for that return means, and accordingly it cannot be used as is with conventionally existing optical connector plugs. Further, although a method that uses a biasing means as the return means for the movable member is shown, that biasing means appears on the outside of the plug, which vitiates its operability and increases the likelihood of a malfunction due to the sandwiching of foreign matter therewithin. Indeed, any structure that covers the body of the plug with a housing intended as a shutter increase the overall size of the plug, which makes it unsuitable for high-density mounting and in which the plug engagement piece is completely covered by the housing, which makes it difficult to guide and complicates fitting when inserting the plug into another connector receptacle. 
       SUMMARY OF THE INVENTION 
       [0008]    The present invention has as its object to solve the above-described problems of the background art and provide a compact, highly compatible shading member-equipped optical connector plug that makes the optical connector plug compact while having the compatibility to engage existing connector receptacles. 
         [0009]    Accordingly, a shading member-equipped optical connector plug according to the present invention comprises an optical connector plug including a synthetic resin plug frame that containably supports a cylindrical stick-shaped ferrule that holds a front end of an optical fiber and a cylindrical ferrule holder assembly that supports said ferrule; a cylindrical synthetic resin stop ring attached to a rear end of said plug frame and to which a front end of a synthetic resin hood that protects an optical cable covering the optical fiber is fitted; a spring that urges the ferrule forward; a planar metal slider engagingly attached to a side wall of the plug frame; and a synthetic resin knob engagingly supported by a pair of engagement projections formed on the slider; and a shading member that blocks light from the optical fiber on a connection side of the optical connector plug, wherein the shading member comprising: a shutter housing enclosing the plug frame slidably on an outside thereof, and inserted into an engagement opening of a connector receptacle to be engaged when the optical connector is connected; a shutter one end of which is supported by said shutter housing at a front part of the housing and another end of which is urged by an elastic force and closes so as to shade the optical fiber at a position in front of the ferrule; and an elastic member disposed between the plug frame and the shutter housing that urges the shutter housing forward. 
         [0010]    In addition, preferably, a pair of flexible engagement pieces is provided on a rear end of the shutter housing, engagement projections that engage said flexible engagement pieces are provided on an outer periphery of said plug frame, and said knob encloses the rear end of said shutter housing and has notches formed in an outer periphery thereof that releases engagement of said flexible engagement pieces outside so as to make the shading member attachable to and detachable from the plug frame. 
         [0011]    Further, preferably, the shutter comprises a pair of opposed shutter pieces disposed within said shutter housing so as to be rotatable about a support shaft, the shutter disposed so as to be urged by said elastic member and close at a position in front of said ferrule, a closing part where front ends of the shutter pieces contact each other disposed so as to project outside front side opening edges of the shutter housing. 
         [0012]    According to the shaded member-equipped optical connector plug of the present invention, since the shutter housing encloses the plug frame slidably on an outside thereof, and inserted into an engagement opening of a connector receptacle to be engaged when the optical connector is connected, attachment can be smooth. Moreover, compatibility is high because even with the addition of the shading member to the plug side, there is no need to make special changes to the configuration on the connected connector receptacle side, and therefore connection can be carried out as conventionally. Further, the shading member does not project outside the external dimensions of the knob of the optical connector plug, and thus poses no obstacle to high-density installation. 
         [0013]    The shading member can be attached to and detached from the optical connector plug and is functionally independent, and thus even when removed from the optical connector plug, poses no problem for the connection function of the plug. Therefore, a shading member removed from one optical connector plug can be used for another optical connector plug. 
         [0014]    The closing parts of the shutter projects from the front side opening edge of the shutter housing, and thus the shutter housing experiences no relative movement when an object strikes the front surface side of the plug connector because it strikes the shutter pieces first. Therefore, there is no looking directly into the light, and further, there is no scratching of the plug connection end surfaces. 
         [0015]    Other features and advantages of the present invention will be apparent from the following description when taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the several views thereof. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0016]      FIG. 1A  is a perspective view from a front side of a partial cross-section of a shading member-equipped optical connector plug according to an embodiment of the present invention; 
           [0017]      FIG. 1B  is a perspective view from the rear side of a partial cross-section of the shaded member-equipped optical connector plug; 
           [0018]      FIGS. 2A   2 B and  2 C are top, side and front views, respectively, of the shading member-equipped optical connector plug; 
           [0019]      FIG. 3A  is a sectional view along a line  3 A- 3 A shown in  FIG. 2A ; 
           [0020]      FIG. 3B  is a sectional view along a line  3 B- 3 B shown in  FIG. 2B ; 
           [0021]      FIG. 4  is a perspective view of a plug frame of the shaded member-equipped optical connector plug; 
           [0022]      FIG. 5  is a perspective view of a slider of the shaded member-equipped optical connector plug; 
           [0023]      FIGS. 6A ,  6 B,  6 C,  6 D, and  6 E are top, front, rear, side, and sectional views along a line  6 E- 6 E shown in  FIG. 6A , respectively, of a knob of the shaded member-equipped optical connector plug, 
           [0024]      FIG. 7  is a perspective view of the shaded member-equipped optical connector plug with the shading member removed; 
           [0025]      FIGS. 8A ,  8 B,  8 C,  8 D,  8 E,  8 F and  8 G are perspective, top, front, rear, side, sectional along a line  8 F- 8 F shown in  FIG. 8E , and sectional views along a line  8 G- 8 G shown in  FIG. 8B , respectively, of a shutter housing of the shaded member-equipped optical connector plug; 
           [0026]      FIGS. 9A ,  9 B,  9 C, and  9 D are top, front, side and rear views, respectively, of a shutter of the shaded member-equipped optical connector plug; 
           [0027]      FIGS. 10A and 10B  are top and side views, respectively, of a shutter spring of the shaded member-equipped optical connector plug; 
           [0028]      FIGS. 11A and 11  B are top and vertical sectional views along a line  11 B- 11 B in  FIG. 11A , respectively, of the shaded member-equipped optical connector plug and a connector receptacle engaged; 
           [0029]      FIGS. 12A and 12B  are side and vertical sectional views along a line  12 B- 12 B in  FIG. 12A , respectively, of the shaded member-equipped optical connector plug and connector receptacle engaged; 
           [0030]      FIGS. 13A and 13B  are top and vertical sectional views along a line  13 B- 13 B in  FIG. 13A , respectively, showing motions of the respective parts when the shaded member-equipped optical connector plug and connector receptacle are just detached; 
           [0031]      FIGS. 14A and 14B  are side and vertical sectional views along a line  14 B- 14 B in  FIG. 14A , respectively, showing motions of the respective parts when the shaded member-equipped optical connector plug and connector receptacle are just detached; and 
           [0032]      FIGS. 15A and 15B  are side and vertical sectional views along a line  15 B- 15 B in  FIG. 15A , respectively, of the shaded member-equipped optical connector plug and connector receptacle completely separated. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0033]    A detailed description will now be given of an exemplary embodiment of the present invention, with reference to the accompanying drawings. In so doing, although specific terminology is employed for the sake of clarity, the present disclosure is not to be limited to the specific terminology so selected. Therefore, it is to be understood that each specific element includes all technical equivalents thereof that operate in a similar manner and achieve a similar result 
         [0034]    As shown in  FIGS. 1A through 3B , a shading member-equipped optical connector plug  1  according to the present invention is provided with a shading member  13  on a connection side of the optical connector plug, which blocks light from an optical fiber  2 . That is, the shading member-equipped optical connector plug  1  is comprised of an optical connector plug including a synthetic resin plug frame  10  that containably supports an assembly of a cylindrical stick-shaped ferrule  3  that holds a front end of the optical fiber  2  and a cylindrical ferrule holder  4  having a front side hole into which the ferrule  3  is pressed so that the cylindrical ferrule holder  4  supports the ferrule  3 , a cylindrical synthetic resin stop ring  6  attached to a rear end of said plug frame  10  and to which a front end of a synthetic resin hood  9  that protects an optical cable  8  covering the optical fiber  2  is fitted, a spring  7  that urges the ferrule forward, a planar metal slider  11  engagingly attached to a side wall of the plug frame  10 , and a synthetic resin knob  12  engagingly supported by a pair of engagement projections  11   a ,  11   b  formed on the slider  11 ; and said shading member  13 . 
         [0035]    The spring  7  contacts an E-shaped ring  5  engaged to circumferential grooves provided on a rear outer peripheral surface of the ferrule holder  4  and uses a step formed in the stop ring  6  as a spring seat, and thus urges the ferrule  3  forward. 
         [0036]    The plug frame  10 , as shown in  FIG. 4 , is a cylinder that the outside is formed into substantially a square and the inside is formed into a cylinder. The inside wall surface of the plug frame  10  slidably supports the ferrule holder  4 , with the front of the ferrule  3  projecting from a front surface side opening  10   a . Engagement portions  10   c  for the slider  11  are formed in lateral wall surfaces  10   b  of the plug frame  10 , in front of which grooves  10   d  are formed to guide and contain the front of the slider  11 . 
         [0037]    This groove  10   d  is formed by providing a pair of walls  10   h ,  10   h  oppositely disposed in a long direction, in which each wall  10   h  has a tapered portion  10   i  to widen a flexible engagement hook  19   d  of another engaged connector receptacle  19  (see  FIGS. 12A and 12B ) on connecting with the plug frame  10  and a vertical portion  10   j  falling vertically from the rear end of a flat surface communicated with the tapered portion  10   i . In a space between the pair of walls  10   h ,  10   h , a release jig  11  of the slider  11  to be described later is received, which is not engaged while connected but releases engagement of the flexible engagement hook  19   d  by moving backward on detaching the engaged connector receptacle  19 . 
         [0038]    Further, concave portions  10   e  that in cross-section form an arc corresponding to roughly one-quarter of a circle are formed in the four comers of the square-shaped plug frame  10  so as to extend all the way to the rear of the plug frame  10  in a long direction thereof. Each of these concave portions  10   e  contains a spring  18  to be described later The springs  18  are supported by spring seats  10   f  at the back, so as to generate a forward-biasing force. 
         [0039]    The slider  11 , as shown in  FIG. 5 , is a planar body of predetermined width, which engages the engagement projections  10   c  of the plug frame  10  and in which is formed at substantially a center portion thereof an engagement hole  11   c  that allows the slider  11  to slide back and forth within a predetermined range. A release jig  11   d  having a tapered portion for releasing engagement of the flexible engagement hook  19   d  of the engaged connector receptacle  19  by moving the knob  12  backward is formed on the front of the slider  11 . A recess  11   e  is formed adjoining the rear end of the releasing jig  11   d  for receiving the flexible engagement hook  19   d . It should be noted that the pair of engagement projections  11   a ,  11   b  engage engagement holes  12   a  in the knob  12  shown in  FIG. 6  to be described later. According to the slider  11 , the flexible engagement hook  19   d  is functioned to be widened separately on connecting and detaching with and from the pair of walls  10   h ,  10   h  and the releasing jig  11   d , and thus incomplete connection of the shading member-equipped optical connector plug  1  with the connector receptacle  19  may not be caused. 
         [0040]    The knob  12 , as shown in  FIG. 6 , is a substantially rectangular cylindrical body that encloses the rear of the plug frame  10 , the front of the stop ring  6 , and a rear of a cylinder-like shutter housing  14  (see  FIG. 8A-8G ) to be described later. A reversed-“C”-shaped concave portion  12   b  is formed in a front end of the knob  12 , in which fits a projection  14   c  that forms an opening  14   a  in the shutter housing  14 . Further, notches  12   c ,  12   c  are formed in a front end side surface, use of which enable engagement by flexible engagement pieces  14   e ,  14   e  of the shutter housing  14  to be released from the outside. 
         [0041]    A shading member  13  is further attached to the front end of the optical connector plug shown in  FIG. 7 . The shading member  13  is comprised of a synthetic resin shutter housing  14 , a shutter  16  (see  FIG. 9 ) a base of which is rotatably mounted on a support shaft  15  itself mounted between shaft holes  14   b  formed in wall surfaces in the long direction of the opening  14   a  provided in top and bottom wall surfaces of the shutter housing  14 , a shutter spring  17  (see  FIG. 10 ) that is an elastic member that continuously urges the shutter  16  so as to close, and the springs  18  (see  FIGS. 3A ,  3 B) that are elastic members that constantly urge the shutter housing  14  forward. 
         [0042]    The shutter housing  14 , as shown in  FIGS. 1A-1B  and in  FIGS. 8A-8G  is shaped substantially as a rectangular cylinder so as to slide along the outside of and enclose the cylinder-shaped plug frame  10  that contains and supports the ferrule  3  that holds the end of the optical fiber  2  as well as to be inserted into the interior of an engagement opening  19   a  of a connector receptacle  19  (see  FIGS. 11A and 11B ) when connecting the optical connector. 
         [0043]    Vertically opposed openings  14   a  are formed in the rectangular cylinder-shaped shutter housing  14 , with a guide projection  14   d  that engages an engagement guide slit  19   b  in the connector receptacle  19  formed on a top surface side of the shutter housing  14 . At the same time, flexible engagement pieces  14   e ,  14   e  that engage rear end surfaces  10   g  of the engagement projections  10   c  of the plug frame  10  and prevent forward slippage of the shutter housing  14  are provided on both lateral wall surfaces of the shutter housing  14 , in the rear ends of which inwardly projecting engagement hooks  14   f  are formed. By releasing the engagement of these flexible engagement pieces  14   e ,  14   e , the shutter housing  14  can be removed from the plug frame  10 , making the shutter housing  14  attachable to and detachable from the plug frame  10 . 
         [0044]    The shutter  16 , as shown in  FIGS. 3A and 3B , is comprised of a pair of pieces  16   a ,  16   b  mounted in the shape of double doors so as to close the front opening in the shutter housing  14 . As shown in  FIGS. 9A-9D , the shutter  16  is a plate made of a metal such as stainless steel, with shaft bearing holes  16   c  formed in both rear comers and a front end  16   d  bent in the shape of an “R”, such that, when the two shutter pieces  16   a ,  16   b  close, these front ends  16   d  contact each other tightly. It should be noted that the shutter may be supported at one end by the shutter housing  14  and formed as a sheet of flexible metal piece that is itself bent so that its other end bends in front of the ferrule  3  and shade the optical fiber  2 . 
         [0045]    The shutter spring  17 , as shown in  FIG. 10 , in the present embodiment is formed as a torsion spring, and mounted on the support shaft  15  in the openings  14   a  in the shutter housing  14  (see  FIGS. 1A and 1B ), so as to urge the fronts of the shutter pieces  16   a ,  16   b  to close in substantially a triangle shape in front of the ferrule  3 . 
         [0046]    The spring  18  is a coil spring, which is contained in each of the concave portions  10   e  that are formed in the four comers of the square-shaped plug frame  10  as shown in  FIG. 4  as well as along an inner circumferential wall of the shutter housing  14  so as to urge the shutter housing  14  forward at all times. Specifically, the rear end of each spring  18  is supported by one of the spring seats  10   f  at the rear of the plug frame  10  and the front end of each spring  18  contacts another spring seat  14   g  provided at the four inside comers of the shutter housing  14 . 
         [0047]    Engagement of the shading member-equipped optical connector plug  1  configured as described above with the connector receptacle  19  is shown in  FIG. 11A  through  FIG. 12B . When the front end of the shutter housing  14  of the shading member-equipped optical connector plug  1  is inserted in the opening  19   a  in the connector receptacle  19 , the guide projection  14   d  is engagingly inserted in the engagement guide slit  19   b  in the connector receptacle  19 , and the front end surface of the projection  14   c  contacts the opening end surface  19   c  and pushes the shutter housing  14  backward against the biasing force of the springs  18 . 
         [0048]    Then, the flexible engagement hooks  19   d ,  19   d  of the connector receptacle  19  slide on the tapered portions  10   i  of the plug frame  10  to ride on the flat portions of the pair of walls  10   h ,  10   h  and further move to fall at the vertical portion  10   j  to be engaged therewith and at the same time to be received in the recess  11   e  of the slider  11  adjoining the rear end of the releasing jig  11   d . By moving the shutter housing  14  backward, the shutter pieces  16   a ,  16   b  contact the cylindrical body of the plug frame  10 , rotate against the biasing force of the shutter spring  17  about the shaft  15 , and contact the outer peripheral wall surface of the plug frame  10  and retreat, enabling light connection of the ferrule  3 . In addition, the projection  14   c  of the shutter housing  14  is engagingly contained within the concave portion  12   b  formed in the front end of knob  12 . 
         [0049]    Thus, as described above, the shading member-equipped optical connector plug  1  engages the connector receptacle  19 . It should be noted that the connector receptacle  19  is pre-existing, and just because there is the shading member  13  in the shading member-equipped optical connector plug  1  does not therefore mean that a special connector receptacle  19  is thus required. 
         [0050]    Next, in order to detach the shading member-equipped optical connector plug  1  from the connector receptacle  19 , as shown in  FIG. 13A  through  FIG. 14B , first, the knob  12  of the optical connector plug  1  is pulled back. When that is done, the knob  12  and the slider  11  engaged together with it are pulled back, which moves the release jig  11   d  of the slider  11  backward. As shown in  FIG. 14B , the slant portion of the release jig  11   d  pushes the flexible engagement hook  19   d  of the connector receptacle  19  out to go widened. As the result, the catch portion of the flexible engagement hook  19   d  comes onto the flat portion of the release jig  11   d , enabling movement to the backward, thus releasing the engagement by pulling the shading member-equipped optical connector plug  1 . 
         [0051]    Thereafter, as shown in  FIGS. 15A and 15B , when the shading member-equipped optical connector plug  1  is pulled backward from the connector receptacle  19 , the front end of the shading member-equipped optical connector plug  1  detaches from the opening  19   a  in the connector receptacle  19 . This detachment results in the shutter housing  14  being urged forward by the springs  18  and the shutter housing  14  moves forward, causing the engagement hooks  14   f ,  14   f  of the flexible engagement pieces  14   e ,  14   e  to catch on the rear end surfaces  10   g  of the engagement portions  10   c  of the plug frame  10 . In addition, this movement forward of the shutter housing  14  causes the fronts of the shutter pieces  16   a ,  16   b  to project forward from the cylindrical body of the plug frame  10 , rotate about the shaft  15  by the biasing force of the shutter spring  17 , and close completely as shown in  FIG. 3 . 
         [0052]    It should be noted that, in the shutter  16 , the two shutter pieces  16   a ,  16   b  are disposed in the shutter housing  14  opposite each other like double doors, such that the front ends of the shutter pieces  16   a ,  16   b  that close together may be configured so as to project outside the edge surfaces of the front opening  14   h  in the shutter housing  14 . For example, the front ends of the closing portion  16   d  of the shutter  16  may be set to project approximately 0.2 mm beyond the end surfaces of the opening in the shutter housing  14 . Such a configuration means that, even when an object strikes the front end of the plug it strikes the plug engagement portion first, and thus the shutter housing  14  experiences no relative movement Therefore, there is no looking directly into the light, and further, there is no scratching of the plug connection end surfaces. 
         [0053]    As many seemingly widely different embodiments and variations of the present invention are possible without departing from the spirit and scope thereof, it is to be understood that the present invention is not limited to the specific embodiments thereof and described herein except as defined in the appended claims.