Abstract:
An optical connector adapter has an optical connection sleeve having a first end portion and a second end portion opposite the first end portion. A sleeve holder has a first cylindrical member having a first through-hole receiving the first end portion of the optical connection sleeve. The sleeve holder is disposed in a tubular housing which has a second cylindrical member having a second through-hole receiving the second end portion of the optical connection sleeve. Engagement members engage the sleeve holder and the housing together in a state that a first end of the first cylindrical member and a first end of the second cylindrical member are abutted against each other. Engagement convex portions project radially inward at respective second ends of the first cylindrical member and the second cylindrical member for regulating movement of the optical connection sleeve in an axial direction.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a structure for supporting an sleeve to optically connect an optical connector adapter that is reduced in the number of parts, and to an optical connector adapter using same. 
     2. Description of the Prior Arts 
     The conventional optical connector adapter represented by an SC type optical connector adapter incorporates an optical connection sleeve to provide alignment between opposite ferrules having therein an optical fiber and to optically couple between the optical fibers. The optical connection sleeve is held by a sleeve holder that is axially divided into two. The sleeve holder is in turn held by a housing axially divided into two. 
     Herein, FIG.  11  and FIG. 12 show an outside appearance and longitudinal view of an SC type connector adapter. As shown in the figures, an optical connection sleeve  101 , such as a split sleeve having a slit, is incorporated in a pair of sleeve holders  102  and  103 . Also, the pair of sleeve holders  102  and  103  are held by a pair of housings  104  and  105 . 
     The sleeve holders  102  and  103  have respective support holes  102   a  and  103   a  to incorporate therein the optical connection sleeve  101 . The support holes  102   a  and  103   a  each have, at one end, a stop  102   b ,  103   b  provided in a circumferential direction and having a circumferential edge inwardly projecting. The stops  102   b  and  103   b  are to abut against an end face of the optical connection sleeve  101  to regulate the optical connection sleeve  101  from moving in an axial direction. Also, the pair of sleeve holders  102  and  103  are of a structure to clamp axially oppositely the optical connection sleeve  101 . Consequently, the axially inner ends are of a fitting structure, at circumferential edges of which are provided flanges  102   c  and  103   c.  The sleeve holders  102  and  103  each have, in radially opposite positions, a pair of claw portions  102   e  and  103   e  having respective engagement claws  102   d  and  103   d  at their tips. 
     On the other hand, the housings  104  and  105  respectively have flanges  104   a  and  105   a  to connect the both and support grooves  104   b  and  105   b  formed in inner surfaces that clamp and support the flanges  102   c  and  103   c  of the sleeve holders  102  and  103 . By welding the flanges  104   a  and  105   a  of the housings  104  and  105  through ultrasonic waves, etc., the sleeve holders  102  and  103  are clamped and held in the support grooves  104   b  and  105   b  formed in the inner peripheral surface of the housings  104  and  105 . Also, the housings  104  and  105  each have, on an opposite side to the flange  104   a ,  105   a , an opening  104   c ,  105   c  in which an optical connector plug can be inserted. 
     Incidentally, one housing  105  is provided, at an outer peripheral surface, with a plate  106  as a metal-make engagement spring to engage with an optical connector mount panel. 
     As described above, the conventional optical connector adapter requires to implement ultrasonic welding, screwing and riveting after combining the five parts. This results in a problem with increased assembling operation and hence mount-up of cost. Also, many parts leads to increase of material cost. 
     Meanwhile, there also is a problem of difficulty in enhancing the accuracy of positioning the left and right housings. There is possibly a case of causing change in optical connection stability, particularly in reproducibility of optical loss upon repeating connector connection and disconnection or in optical loss when applying tension or bending to an optical fiber cord. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide, in view of the above circumstances, a support structure of an optical connection sleeve for an optical connector adapter, and an optical connector adapter, which are reduced in the number of parts and improved in the accuracy of positioning left and right housing. 
     A first form of the present invention to solve the problem lies in an optical connector adapter having a penetration hole for incorporate and support an optical connection sleeve, comprising: a sleeve holder integrally provided with a first cylindrical member forming lengthwise one end of the penetration hole; a housing integrally provided with a second cylindrical member forming the lengthwise other end of the penetration hole and having a shape to internally hold the sleeve holder; engagement means for engaging the sleeve holder and the housing in a state that the first cylindrical member and the second cylindrical member at respective one ends are abutted against each other; and engagement convex portions integrally formed projecting radially inward at respective other ends of the first cylindrical member and the second cylindrical member to regulate the optical connection sleeve from moving in an axial direction. 
     A second form of the invention lies in an optical connector adapter, wherein in the first form the engagement means has an engagement pin inserted and held in the housing in a state that the sleeve holder is assembled with the housing, and an engagement portion integrally provided on the sleeve holder to engage the engagement pin in a state combined with the housing. 
     A third form of the invention lies in an optical connector adapter, wherein in the first form the engagement means has an engagement claw provided on any one of the housing and the sleeve holder to be elastically deformable in an radial direction, and an engagement recess provided on the other to engage the claw. 
     A fourth form of the invention lies in an optical connector adapter, wherein in any of the first to third forms the housing is formed with an aperture to be coupled with an optical connector plug. 
     In the optical adapters of the invention, the optical connector adapter can be assembled by merely assembling the housing with the sleeve holder through the engagement means in a state an optical connection sleeve is internally assembled. 
     A fifth form of the invention lies in an optical connector adapter, each pair of claw portions are provided appositely of shorter sides of the flange such that they sandwich the first cylindrical member and the housing second cylindrical member, and have a pair of claw portions and having engagement claws at tips. These claw portions are to couple with an optical connector plug. Further the claw portion having a thickness continuously decreasing toward the engagement claw. 
     The claw portion of the above form can reduce the strength of deforming the claw portion when coupling a connector plug. As a result, an optical connector adapter is available that is easy to couple. 
     A sixth form of the invention lies in an optical connector adapter, wherein in the fifth form the claw portion is in a concave form on an outer periphery side of the cylindrical member. By forming in a concave-form curved surface, it is possible to prevent fatigue and breakage in the claw portion due to repetition of connector plug connection and disconnection. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an exploded perspective view of an optical connector adapter according to Embodiment 1 of the present invention; 
     FIG. 2 is a perspective view partly cut away of a housing of the optical connector adapter according to Embodiment 1 of the present invention; 
     FIG. 3 is a perspective view partly cut away of a sleeve holder of the optical connector adapter according to Embodiment 1 of the present invention; 
     FIG. 4 is a perspective view partly cut away of the optical connector adapter according to Embodiment 1 of the present invention; 
     FIG. 5 is an exploded perspective view of an optical connector adapter according to Embodiment 2 of the present invention; 
     FIG. 6 is a perspective view partly cut away of a housing of the optical connector adapter according to Embodiment 2 of the present invention; 
     FIG. 7 is a perspective view partly cut away of a sleeve holder of the optical connector adapter according to Embodiment 2 of the present invention; 
     FIG. 8 is a perspective view partly cut away of the optical connector adapter according to Embodiment 2 of the present invention; 
     FIG. 9 is an exploded perspective view of an optical connector adapter according to Embodiment 3 of the present invention; 
     FIG. 10 is a perspective view partly cut away of the optical connector adapter according to Embodiment 3 of the present invention; 
     FIG. 11 is a perspective view partly cut away of an SC type optical connector adapter according to a prior art; 
     FIG. 12 is a sectional view the an SC type optical connector adapter according to the prior art; 
     FIG. 13 is a perspective view of a sleeve holder of the optical connector adapter of the present invention; 
     FIG. 14 is a sectional view of a claw portion of the invention; 
     FIG. 15 is an exploded perspective view of an optical connector adapter according to Embodiment 6 of the present invention; 
     FIG. 16 is a perspective view partly cut away of a sleeve holder of the optical connector adapter according to Embodiment 6 of the present invention; 
     FIG. 17 is a perspective view partly cut away of a housing of the optical connector adapter according to Embodiment 6 of the present invention; 
     FIG. 18 is a perspective view partly cut away of the optical connector adapter according to Embodiment 6 of the present invention; and 
     FIGS. 19A-B are a sectional view and a side view of the optical connector adapter according to Embodiment 6 of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will now be described with reference to the drawings. 
     (Embodiment 1) 
     FIG. 1 is an exploded perspective view of an optical connector adapter according to Embodiment 1. FIG. 2 is a perspective view partly cut away of a housing of the same, FIG. 3 is a perspective view partly cut away of a sleeve holder with of the same, and FIG. 4 is a perspective view partly cut away of an assembly state. 
     An optical connector adapter  10  of this embodiment is an SC type optical connector adapter having a sleeve holder  20  and a housing  30  supporting the sleeve holder  20 . 
     The sleeve holder  20  has a first cylindrical member  21  forming a lengthwise one end of a penetration hole  11  to incorporate an optical connection sleeve  1 . The first cylindrical member  21  has, at an axial one end, a stop claw  22  formed projecting radially inward to engage the optical connection sleeve  1 . The first cylindrical member  21  also has, at the other end, a rectangular-formed flange  23  provided on an outer periphery thereof. 
     Meanwhile, each pair of claw portions  24  and  25  are provided oppositely of shorter sides of the flange  23  such that they sandwich the first cylindrical member  21  and the housing second cylindrical member, hereinafter referred, and have a pair of claw portions  24  and  25  having engagement claws  24   a and  25   a  at tips. These claw portions  24  and  25  are to couple with an optical connector plug. The flange  23  also has a pair of engagement protrusions  26  provided at respective ends of the shorter sides thereof. The flange  23  has a recess  27  formed in an opposite surface to the first cylindrical member  21 . 
     The housing  30  has a penetration hole  31  with a structure to incorporate therein a sleeve holder  20 . Grooves  32  are provided oppositely of shorter sides of the penetration hole  31 , with which the ends of the flange  23  are respectively fitted. Meanwhile, on an opposite side to insertion from an axial center in the penetration hole  31  toward the flange  23 , there are provided a flange  33  to fit with the recess  27  of the flange  23  and a second cylindrical member  34  axially extending from the flange  33 . The second cylindrical member  34  has, at end, a stop claw  35  projecting radially inward to engage the optical connection sleeve  1 . The flange  33  has, oppositely of shorter sides, insertion holes  36  in which a pair of claw portions  25  are respectively to be inserted. 
     The housing  30  has a wall provided with an insertion groove  37  formed by a groove penetrated on widthwise opposite sides so that an engagement pin  40  can be inserted to engage between the sleeve holder  20  and the housing  30 . 
     Here, the engagement pin  40  in this embodiment is in generally a squared-U form having a pair of arms  41  for insertion in the penetration hole  37   a  is engagable with the engagement protrusion  26  of the sleeve holder  20 . 
     On the other hand, a fixing flange  38  is provided at axial center on a side surface of a shorter side of the housing  30 . The fixing flange  38  is provided with a fixing groove  38   a  to fix the housing  30 . Furthermore, on opposite side surfaces of the shorter sides on axial one side of the housing  30  and surfaces between them, respective continuing recesses  39  are formed. The recesses  39  are to be fitted with a plate  50  that has a metal engagement claw  51  and in a squared-U form. 
     To assemble an optical connector adapter  10  in this embodiment explained above, the sleeve holder  20  is inserted in the housing  30  with optical connecting sleeve  1  sandwiched between the first cylindrical member  21  and the second cylindrical member  34 . Then the engagement pin  40  may be inserted in the insertion groove  37 . 
     Here, each of the sleeve holder  20  and the housing  30  can be integrally formed. The sleeve holder  20  is preferably formed by plastic molding, and the housing  30  is preferably by plastic molding, metal injection molding (MIM) or die cast. 
     (Embodiment 2) 
     FIG. 5 is an exploded perspective view of an optical connector adapter according to Embodiment 2. FIG. 6 is a perspective view partly cut away of a housing of the same, FIG. 7 is a perspective view partly cut away of a sleeve holder of the same, and FIG. 8 is a perspective view partly cut away of an assembly state. 
     An optical connector adapter  10 A of this embodiment is same in basic structure as that of Embodiment 1 except for differences therefrom in a sleeve holder  20 A and in engagement means for engaging a housing  30 A holding the sleeve holder  20 A. Hence, the same elements having a same function are denoted by the same reference characters to omit duplicated explanations. 
     The sleeve holder  20 A is different from that of Embodiment 1 in that a pair of guide member  61  are provided standing, along a pair of claw portions  24 , at ends on shorter sides of a rectangular flange  23  provided on an outer periphery at an end of a first cylindrical member  21  and an engagement protrusion  65  is provided on an outer side of a tip of the guide member  61 . Also, the guide member  61  is formed with a window  63  in an opposed position to the claw portion  24  not to interfere with elastic deformation of the claw portion  24 . Incidentally, the pair of guide members  61  have an exterior dimension to generally fit with the penetration hole  31  of the housing  30 A. 
     On the other hand, the housing  30 A is different from that of Embodiment 1 in that an engagement hole  69  is provided in a side surface with which an engagement protrusion  65  provided in the guide member  61  engages. 
     To assemble an optical connector adapter  10  of the present embodiment explained above, the sleeve holder  20 A is inserted in the housing  30 A with the optical connection sleeve  1  sandwiched between the first cylindrical member  21  and the second cylindrical member  34 . Then the engagement protrusion  65  of the guide member  61  may be engaged with the engagement hole  69  of the housing  30 A. 
     (Embodiment 3) 
     FIG. 9 is an exploded perspective view of an optical connector adapter according to Embodiment 3. FIG. 10 is a perspective view party cut away of an assembly state. 
     An optical connector adapter  10 B of this embodiment is similar in basic structure to that of Embodiment  2  except that it is an MU type optical connector adapter. Hence, the same elements having a same function are denoted by the same reference characters to omit duplicated explanations. The connector adapter  10 B has a sleeve holder  20 B and a housing  30 B supporting the sleeve holder  20 B. 
     The sleeve holder  20 B has a first cylindrical member  21 B forming a lengthwise one end of a penetration hole  11 B to incorporate an optical connection sleeve  1  which has small radius for MU type optical connector. The first cylindrical member  21 B has, at an axial one end, a stop claw  22 B formed projecting radially inward to engage the optical connection sleeve  1 B. The first cylindrical member  21 B also has, at the other end, a rectangular-formed flange  23 B provided on an outer periphery thereof. The flange  23 B is provided guide members  71  on respective short-side side. 
     The guide members  71  have an exterior shape to be generally fit with guide grooves  32 B provided in a penetration hole  31 B of the housing  30 B, hereafter referred. At inner side of the guide member  71 , respective one pairs of engagement claws  72  and  73  are provided. These engagement claws  72  and  73  are to couple with an MU type connector plug. Also, an engagement protrusion  75  is provided at an outside of the first cylindrical member  21 B of the guide member  71 . 
     On the other hand, the housing  30 B has guide grooves  32 B with which the guide members  71  is to be fit, and an engagement hole  79  with which the engagement protrusion  75  is to be engaged. Incidentally, the housing  30 B in its surface is formed with a recess  39 B with which a plate  50 B having an engagement claw  51 B is to be fit. 
     To assemble an optical connector adapter  10 B in this embodiment explained above, the sleeve holder  20 B is inserted in the housing  30 B with optical connecting sleeve  1 B sandwiched between the first cylindrical member  21 B and the second cylindrical member  34 B. Then the engagement protrusion  75  of the guide member  71  may be engaged with the engagement hole  79  of the housing  30 B. 
     (Embodiments 4 and 5) 
     FIG. 13 is a perspective view partly cut away of a sleeve holder, wherein on an outer peripheral side of the claw portion  24 ,  25  a slant surface is formed having a thickness decreasing toward an axial outer side. FIG. 14 is a figure showing a state of a mechanical strength when the elastic deformation of the claw portion  24  becomes a maximum. The elastic deforming portion has a length L of 6.2 mm and the width of the elastic deforming portion in a vertical direction of the figure is 4 mm. Here, the maximum stress σ at a region A can be by providing a thickness T 1  of 1.0 mm or greater to a root of the claw portion  24  and a continually decreasing thickness T 2 , e.g. of 0.5 mm to 0.9 mm, to a connection portion with a tip engagement recess. In the figure, a sectional form of the claw portion at outer side of the cylindrical member is a concave-formed curved surface. Also, because the reduction in elastic load P can also be avoided in the vicinity of the engagement recess, there is no inconvenience for coupling and disconnection operation between the optical connector plug and the optical connector adapter. 
     Here, by setting T 1  as a maximum claw thickness at from 1.0 mm to 1.2 mm and T 2  as a minimum thickness at from 0.6 mm to 0.8 mm, the maximum stress a at the region A becomes 12 to 16 kgf/mm 2 . The elastic load for this case can be given from 1.0 to 1.5 kgf. 
     (Embodiments 6) 
     FIG. 15 is an exploded perspective view of an optical connector adapter according to Embodiment 6 of the present invention. FIG. 16 is a perspective view partly cut away of a sleeve holder of the optical connector of the same. FIG. 17 is a perspective view partly cut away of a housing of the optical connector adapter of the same. FIG. 18 is a perspective view partly cut away of the optical connector adapter of the same. FIG. 19A is a sectional view from cut line K of FIG. 19B, which is a side view of the optical connector adapter of the same. 
     An optical connector of this invention has a pair of sleeve holder  20 , corresponding sleeve  1  and a housing  30  supporting the sleeve holders  20 . The sleeve holder  20  has a first cylindrical member  21  forming a lengthwise one end of a penetration hole  11  to incorporate an optical connection sleeve  1 . The first cylindrical member  21  has, at an axial one end, a stop claw  22  formed projecting radially inward to engage the optical connection sleeve  1 . Further a pair of guide members  81  has a pair of engagement protrusions  85 . 
     The housing  30  has a flange  33  and a second cylindrical member  34  axially extending from the flange  33 . The second cylindrical member  34  has, at end, a stop claw  35  projecting radially inward to engage the optical connection sleeve  1 . 
     (Others) 
     As explained above, according to the present embodiment, the number of parts for the SC type optical connector adapter can be reduced from conventional six to four, thus reducing cost. 
     Also, assembling operation is possible, for example, only by driving a pin with omitting ultrasonic welding, screwing, riveting or the like, thereby greatly simplifying operation process. 
     Furthermore, because the housing is made integral, the shaft having a shape to receive the plug does not deviate left and right, enabling stable optical connection. 
     Although the present embodiment was explained by exemplifying the SC type, MU type or LC type optical connector adapter, the invention is not limited to that structure. It is needless to say that the invention is applicable to other similar adapters. 
     As explained above, according to the present embodiment, because the number of parts for the SC type optical connector adapter can be reduced from conventional six to four and assembling operation can be greatly simplified, it is possible to greatly reduce cost.