Patent Publication Number: US-2020284993-A1

Title: Optical fiber connector

Description:
CROSS-REFERENCES TO THE APPLICATION IN QUESTION 
     This Application is a Continuation of U.S. patent application Ser. No. 15/528,451, filed on 2 Oct. 2017, which is a National Stage Application of PCT/CN2015/095191, filed on 20 Nov. 2015, which claims benefit of Serial No. 201420700716.8, filed on 20 Nov. 2014 in China, and which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications. 
    
    
     TECHNICAL FIELD 
     In overall terms, this disclosure relates to a type of connector system, more specifically an optical fibre connector of a type of connector system. 
     PRIOR ART 
     Optical cables are widely used for the transmission of optical signals thus allowing high speed transmission of data. Optical cables generally comprise: one or more optical fibres, one or more buffer components surrounding the optical fibres, a reinforced layer surrounding said one or more buffer components and an external protective cover. Optical fibres are for the purpose of carrying optical signals. A typical optical fibre includes an internal core component surrounded by an encapsulating layer, the encapsulating layer being covered by a coating layer. Said buffer component (either a loose or tight buffer tube) is used to enclose and protect the coated optical fibre. The reinforced layer increases the mechanical strength of the optical cable, thus preventing strain being exerted on the optical fibre during installation or during subsequent processes. Examples of reinforced layers include aramid yarn, steel and epoxy reinforced glass roving. The external protective cover prevents damage due to crushing, abrasion and other physical damage. The external protective cover also prevents chemical damage (for instance by ozone, alkalis or acids). 
     Optical cable connector systems are useful in allowing in-situ connection and disconnection of optical cables where splicing is not necessary. A typical optical cable connector system connecting two optical cables includes optical fibre connectors installed at the ends of the optical cables, and an adapter that couples the optical fibre connectors together both optically and mechanically. Optical fibre connectors typically consist of an insertion core which supports the optical cable at its end. Typically, the end surface of the insertion core is at an angle and polished. The adapter includes a coaxial alignment port (such as a socket) capable of containing the optical fibre connectors requiring connection. The adapter includes an internal sleeve tube; when the connector is inserted into the said port of the adapter, said internal sleeve tube accommodates and aligns with the insertion core of the said optical fibre connector. When the insertion core and the optical fibre with which it is connected are aligned correctly within the sleeve tube of the optical fibre adapter, the optical fibre signal can be transmitted from one optical fibre to the next optical fibre. Typically, adapters also include mechanical securing devices to ensure that the optical fibre connector is mechanically retained within the adapter. 
     Typically, the housing wall of an MST or OTE housing (enclosure) in the adapter is captured by a raised edge on the adapter for instance in an arrangement such as a threaded nut fixing, the optical fibre connector system being installed within the housing by passing through an opening of a suitable size. The interaction between the raised edge of the adapter and the nut compresses a component, for instance a sealing “O” ring, thus achieving a sealed connection. 
     Our intention was to improve the optical fibre connector system. 
     SCOPE OF THE INVENTION 
     According to one aspect of this invention, it provides a type of connector system, which consists of: an adapter body with a first locking component; an extending raised edge which surrounds the said adapter body, that raised edge possessing a first connecting surface; and a locking ring, that locking ring being constructed such that it may be installed around the adapter body, said locking ring possessing a second connecting surface and a second locking component; said first locking component and said second locking component being constructed such that they connect together when said locking ring is rotated by an angle of 90 degrees or less than 90 degrees relative to the adapter body, thus allowing the positioning of the first connecting surface at a pre-set distance from the second connecting surface. 
     According to one illustrative embodiment of this invention, the adapter body is more or less cylindrical, the first locking component possessing a first protruding locking section and second protruding locking section extending radially from the adapter body. 
     According to one illustrative embodiment of this invention, the first locking component includes a first locking surface. 
     According to one illustrative embodiment of this invention, the second locking component includes a second locking surface being constructed such that it may connect with the first locking surface. 
     According to one illustrative embodiment of this invention, the second locking surface includes a first section at an angle to the second connecting surface and a second section that is parallel to the second connecting surface. 
     According to one illustrative embodiment of this invention, said second locking surface includes a stepped section between said first section and said second section. 
     In one illustrative embodiment of this invention, the connector system further includes a ribbed section adjacent to said stepped section, said ribbed section extending radially inwards into the central opening of said locking ring. 
     According to one illustrative embodiment of this invention, the connector system further includes a sealing component contained within said adapter body. 
     According to one illustrative embodiment of this invention, said locking ring delimits the central opening of said adapter body contained therein, while the second locking component protrudes radially inwards into said central opening. 
     According to one illustrative embodiment of this invention, the central opening of the locking ring is delimited by an axial slot constructed such that it contains said first locking component. 
     According to another aspect of this invention, it provides a type of connector system, which consists of: an adapter body that possesses a first end section and a second end section; a raised edge that surrounds the first end section of the said adapter body; a first locking component, said first locking component extending from the second end section of said adapter body and possessing a first locking surface; a locking ring, said locking ring possessing a central opening delimited by an axial slot, said axial slot being constructed such that it contains said first locking component; and a second locking component, said second locking component extending into said central opening and being constructed such that it connects with the second locking surface of said first locking surface. According to one illustrative embodiment of this invention, this connector system further includes: a first connecting surface delimited by said raised edge; a second connecting surface delimited by said locking ring; wherein, said first locking component and said second locking component are positioned such that they connect together when said locking ring is rotated by an angle of 90 degrees or less than 90 degrees relative to the said adapter body, their connection allowing the positioning of the said first connecting surface at a pre-set distance from the said second connecting surface. 
     According to one illustrative embodiment of this invention, the adapter body is more or less cylindrical, the first locking component possessing a first protruding locking section and a second protruding locking section extending radially from the adapter body. 
     According to one illustrative embodiment of this invention, said locking ring delimits a central opening, and additionally the second locking component includes a first protruding locking section and a second protruding locking section extending radially into said central opening. 
     According to one illustrative embodiment of this invention, this connector system further includes an installation tool, said installation tool comprising: a body; and a first dowel pin and second dowel pin extending axially from said body, wherein said locking ring delimits a first hole and second hole, the first hole and second hole being such that said first pin and said second pin can fit within them. 
     According to one illustrative embodiment of this invention, said locking ring possesses a first end section that delimits a connecting surface, and additionally, the second locking surface includes a first section at an angle relative to said connecting surface and a second section parallel to said connecting surface. 
     According to one illustrative embodiment of this invention, said second locking surface includes a stepped section between said first section and said second section. 
     According to one illustrative embodiment of this invention, the connector system further includes a ribbed section adjacent to said stepped section, said ribbed section extending radially inwards to the central opening of said locking ring. 
     According to one illustrative embodiment of this invention, said first locking component includes a first protruding locking section and a second protruding locking section extending radially from said adapter body, and additionally said central opening delimits and is for the purpose of containing the first axial slot and second axial slot of said first protruding locking section and said second protruding locking section. 
     According to one illustrative embodiment of this invention, the second locking component comprises a first protruding locking section and second protruding locking section extending into said central opening. 
    
    
     
       DESCRIPTION OF DRAWINGS 
         FIG. 1  is a 3-dimensional exploded view of various aspects of one embodiment of the optical fibre connector disclosed here; 
         FIG. 2  is another exploded view of the optical fibre connector depicted in  FIG. 1 ; 
         FIG. 3  is a perspective drawing of the components shown in  FIG. 1  and  FIG. 2  connected together; 
         FIG. 4  is a perspective drawing of one embodiment of the locking ring of the optical fibre connector system shown in  FIGS. 1 to 3 ; 
         FIG. 5  is an end elevation drawing of the locking ring shown in  FIG. 4 ; 
         FIG. 6  is a cut-away side view of the locking ring shown in  FIG. 4  and  FIG. 5 ; 
         FIG. 7  is a perspective drawing of one embodiment of the adapter of the optical fibre connector system shown in  FIGS. 1 to 3 ; 
         FIG. 8  is a partial perspective drawing of the optical fibre housing shown in  FIGS. 1 to 3 ; 
         FIG. 9  is a perspective drawing of the part of the optical fibre housing shown in  FIG. 8  which accommodates the adapter shown in  FIG. 7 ; 
         FIG. 10  provides a further sectional view of the various aspects of an embodiment of the optical fibre system disclosed herein; 
         FIG. 11  is a perspective drawing of the various aspects of an embodiment of the installation tool disclosed herein; and 
         FIG. 12  is a sectional view of the installation tool shown in  FIG. 11  connected to the optical fibre connector system shown in  FIG. 10 . 
     
    
    
     DETAILS OF THE EMBODIMENTS 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and the drawings are shown by way of illustration of specific embodiments of the invention. In this respect, where terms such as “top”, “bottom”, “front” or “back” are used in the description, reference should be made to the drawing or drawings to which they apply. Due to it being possible to orientate the components referred to in the embodiments in a number of different directions, the terms of direction are only used for descriptive purposes, and should not be seen as being in any way restrictive. It should be appreciated that, other embodiments and any modification of the structure or logic without departing from the scope of this invention would be possible. In view of this, the following detailed description should not be understood as restricting the scope of this disclosure. 
     For instance, the optical cables used in communication are commonly connected to one another using a wide variety of types of connectors. Optical cables are widely used for the high-speed transmission of data via the transmission of optical signals. Optical cables generally comprise: (1) one or more optical fibres; (2) one or more buffer components surrounding the optical fibres; (3) a reinforced layer surrounding said one or more buffer components; and (4) an external protective cover. Optical fibres are for the purpose of carrying optical signals. A typical optical fibre includes an internal core component surrounded by an encapsulating layer, the encapsulating layer being covered by a coating layer. The aforementioned buffer component (either a loose or tight buffer tube) is used to enclose and protect the coated optical fibre. The reinforced layer increases the mechanical strength of the optical cable, thus preventing strain being exerted on the optical fibre during installation or during subsequent processes. Examples of reinforced layers include aramid yarn, steel and epoxy reinforced glass roving. The external protective cover prevents damage due to crushing, abrasion and other physical damage. The external protective cover also prevents chemical damage (for instance by ozone, alkalis or acids). 
     Optical cable connector systems are useful in allowing in-situ connection and disconnection of optical cables where splicing is not necessary. A typical optical cable connector system connecting two optical cables include optical fibre connectors installed at the ends of the optical cables, and an optical fibre adapter that couples the optical fibre connectors together both optically and mechanically. Optical fibre connectors typically consist of an insertion core which supports the optical cable at its end. Typically, the end surface of the insertion core is at an angle and polished. The optical fibre adapter includes a coaxial alignment port (such as a socket) capable of containing the optical fibre connectors requiring connection. The optical fibre adapter includes an internal sleeve tube; when the connector is inserted into the port of the optical fibre adapter, said internal sleeve tube accommodates and aligns with the insertion core of the said optical fibre connector. When the insertion core and the optical fibre with which it is connected are aligned correctly within the sleeve tube of the optical fibre adapter, the optical fibre signal can be transmitted from one optical fibre to the next optical fibre. Typically, adapters also include mechanical securing devices to ensure that the optical fibre connector is mechanically retained within the adapter. 
       FIGS. 1 to 3  show various sections of various aspects of one embodiment of the optical fibre connector system  100  disclosed herein. The system  100  illustrative of this embodiment comprises an adapter  110  with an adapter body  112 , the adapter body  112  of the adapter possesses a ring-shaped raised edge  114  surrounding and extending from one end of the adapter body  112 . By clamping the wall  10  of a housing such as an MST or OTE housing between the adapter&#39;s raised edge  114  and the locking ring  120  of the adapter  110 , the connector system  100  depicted in the drawings can be installed onto the opening on the housing. More specifically, the raised edge  114  possesses a first connecting surface  116  for connecting to one side of the housing wall  10 , the locking ring possessing a second connecting surface  122  for connecting to the opposite side of said wall  10 . In the embodiment shown in the drawing, the interaction between the adapter  110  and the locking ring  120  compresses a sealing component such as an “O” ring  130  between the first connecting surface  116  and said wall  10 , thus providing a sealed connection. 
     Many of the connector systems of the current art rely on a threaded nut, rather than a locking ring  120  such as that shown in the drawing, and when connections are made relying on the current art, the nut is contained within the adapter body by a threaded connection, rotation of the nut tightening the nut on the adapter&#39;s raised edge thus compressing the “O” ring. However, due to the general lack of space within the housing, rotation of the nut by a number of turns in order to achieve the intended seal by tightening the nut sufficiently presents difficulties and takes time. Furthermore, it is difficult to determine at what stage the nut has been tightened sufficiently, and generally a torque wrench is required to determine that an appropriate level of torque has been applied. 
     According to this invention, the adapter body  112  possesses a first locking component  140  extending from the adapter body  112 . More specifically, the first locking component  140  of the connector system  100  shown comprises two protruding locking sections  140   a  and  140   b,  the protruding locking sections  140   a  and  140   b  extending from the end of the cylindrical adapter body  112  opposite to that which possesses the raised edge  114 , thus separating the first locking component  140  from the raised edge  114 . As shown in  FIG. 2 , the adapter body  112  is inserted into the housing wall  10  via opening  12 , resulting in the “O” ring  130  being positioned between the connecting surface  116  of the raised edge  114  and the surface of said wall  10 . As shown in  FIG. 3 , the locking ring  120  is positioned on the adapter body  112 . The locking ring  120  possesses a second locking component  150 , that second locking component  150  being constructed such that by partially rotating the locking ring  120  relative to the adapter body  112  bringing it into contact with the first locking component  140  results in the positioning of the first connecting surface  116  at a pre-set distance from the second connecting surface  122 . In certain embodiments, the locking ring  120  is rotated less than 360 degrees in order to secure the adapter  110  and seal it to the wall  10 ; additionally, in the embodiment depicted, rotation of 90 degrees or less allows locking and sealing of the adapter  110 . 
     In other words, it is no longer necessary to rotate a nut repeatedly in order to tighten the adapter so as to compress the “O” ring on the housing, the adapter  110  and locking ring  120  of the system  100  shown in the drawings possessing a first locking component  140  and a second locking component  150 , the interaction between the first locking component  140  and the second locking component  150  positions the first connecting surface  116  and the second connecting surface  122 , allowing the intended compression of said “O” ring  130  to be achieved, the angle of rotation of the locking ring  120  being less than 90 degrees. 
     In certain embodiments, the connector system  100  is used to connect external optical cable (for instance, optical cables from external equipment external to the housing) to optical cable within the housing  10 . The external optical cable is contained within the adapter  110  and carries the optical signal to the housing  10 , the optical fibre connector system  100  allowing that signal to be transmitted from an external optical cable to another optical cable within the housing  10 . As a result of this, in certain embodiments, the connector system  100  is hardened or strengthened. Such hardening or strengthening means that the adapter  110  of the connector is suitable for use in outdoor environments. For instance, the “O” ring  130  is compressed in position by the adapter  110  and the locking ring  120 , achieving the desired environmental seal, thereby preventing axial and/or radial entry of damp/water. In certain embodiments, the said connector system  100  revealed is used to achieve an IP68 grade seal. 
       FIGS. 4 to 6  further depict various aspects of the locking ring  120  shown in  FIGS. 1 to 3 ,  FIG. 7  depicting an embodiment of the adapter  110 . The locking ring  120  has a central opening  124 , that central opening  124  being constructed such that it holds the adapter body  112  shown in  FIG. 3 . Referring to  FIGS. 4 to 6 , the second locking component  150  extends into the central opening  124  of the locking ring  120 . In the embodiment depicted in the drawings, the locking component possesses a first and second protruding locking sections  150   a  and  150   b,  which protrude radially into the central opening  124 . 
     The central opening  124  further delimits a slot  126  extending axially from the connecting surface  122  to the end opposite the locking ring  120 . The slot  126  is delimited by the axial side  128  of the protruding locking sections  150   a  and  150   b  of the second locking component  150 , its size and shape corresponding to that of the protruding locking sections  140   a  and  140   b  of the first locking component  140  of the adapter  110 . This allows the protruding locking sections  140   a  and  140   b  to slide along the slot  126  as the locking ring  120  rotates around the adapter body  112  as shown in  FIG. 3 . As a result of this, the locking ring  120  rotates relative to the adapter body  110 , causing the first locking component  140  of the adapter  110  to come into contact with the second locking component  150  of the locking ring  120 . 
     In the embodiment revealed, each of the protruding locking sections  150   a  and  150   b  of the second locking component  150  is delimited by the locking surface  152 ; when the locking ring  120  is rotated relative to the adapter  110 , that locking surface  152  connects with the locking surface  142  corresponding to the protruding locking sections  140   a  and  140   b  of the first locking component  140  extending from the adapter body  112 . The locking surface  152  comprises an angled or slanted first section  154  and a second section  156  more or less parallel to the connecting surface  122 . As a result of this, when the locking ring  120  is rotated, the locking surfaces  142  of the protruding locking sections  140   a  and  140   b  of the first locking component  140  connect with the slanted first section  154 , as a result of which, as the locking surface  142  slides upwards along the angled first section  154 , it causes the connecting surface  116  of the adapter  110  and the connecting surface  122  of the locking ring  120  to move relative to each other in an axial direction. As the locking ring  120  continues to rotate, the locking surface  142  connects with the second section  156 . The second section  156  of the protruding locking sections  150   a  and  150   b  of the second locking component  150  is axially positioned, allowing the positioning of the first and second connecting surfaces  116  and  122  at pre-set distances from each other. The axial distance between connecting surfaces  116  and  122  depends on the thickness of the wall  10  and the amount of compression required to be exerted on the “O” ring  130 . 
     In the embodiment depicted, the stepped section  158  is located between the second section  156  of the locking surface  152  and the slanting first section  154 . When the locking surface  142  of the first locking component  140  rotates relative to the locking ring  120  and passes the angled first section  154 , the protruding locking sections  140   a  and  140   b  of the first locking component  140  are positioned axially between the axial sides  128  of the stepped sections  158  of the protruding locking sections  150   a  and  150   b  of the second locking component. The stepped sections  158  lock the protruding locking sections  140   a  and  140   b  of the first locking component  140  in place, and prevent the rotation of the locking ring  120  in the opposite direction. Furthermore, as the protruding locking sections  140   a  and  140   b  of the first locking component  140  pass the stepped sections  158  and come into contact with the second section  156  of the locking surface  152 , the “clicking” (snapping) that occurs provides an indication to the operator that the locking ring  120  has already been sufficiently rotated to cause it to lock into position. 
     Furthermore, in the embodiment shown in  FIGS. 4 to 6 , the ribbed section  160  extends radially inwards into the central opening  124 . The ribbed section  160  is positioned such that it is adjacent to each of the stepped sections  158  of the locking surface  152 , extending axially along the central opening  124 . When the protruding locking sections  140   a  and  140   b  of the first locking component  140  pass through the ribbed section  160 , the force required to rotate the locking ring  120  is reduced, giving further indication to the operator that installation is complete. Once the locking surface  142  of the first locking component  140  has already connected with the second section  156  of the locking component  150 , the ribbed section  160  is also capable of preventing rotation of the locking ring in the opposite direction. 
     In certain embodiments, the first locking component  140  and second locking component  150  of the adapter  110  and locking ring  120  both extend around 1.5 mm. As a result of this, the protruding locking sections  140   a  and  140   b  of the first locking component  140  both extend radially outwards from the adapter body  112  by around 1.5 mm, while the protruding locking sections  150   a  and  150   b  of the second locking component  150  extend radially into the central opening  124  by around 1.5 mm. As depicted in  FIGS. 4 to 6 , the central opening  124  is such that it has a first diameter d 1  of around 14.5 mm delimited by the internal surfaces of the protruding locking sections  150   a  and  150   b  of the second locking component  150 , while the internal surface of slot  126  delimits a second diameter d 2  of around 17.5 mm. The second section  156  of locking component  150  delimits a width w of around 7.3 mm. 
     The first locking component  140  and second locking component  150  are arranged such that locking surface  142  connects with the second section  156  of locking surface  152 , as a result of which, when locking ring  120  is rotated by a certain locking angle θ the locking ring  120  becomes locked in position relative to the adapter  110 . In certain embodiments, the locking rotation angle θ is less than 360 degrees. In certain embodiments, the locking ring  120  becomes locked at an angle of rotation of less than 90 degrees, and in the embodiment shown in the drawings, the locking angle θ is around 85 degrees to 87 degrees. 
     Referring to  FIGS. 7 to 9 , the adapter  110  includes a module that locks the adapter  110  in position within the housing  10  and that prevents the adapter  110  from rotating once the locking ring  120  of the adapter has been rotated into position. Key  180  extends beneath the raised edge  114  of the adapter body  112 . Furthermore, raised edge  114  delimits two flat sections  182  on its opposite side. Key  180  is contained within the slot  14  formed by the opening  12  extending through the housing  10 . In the embodiment shown in  FIGS. 7 and 8 , the opening  12  is enclosed by the sleeve ring  16  extending across the external surface of the housing  10 . The sleeve ring  16  delimits the flat section  18  that interacts with the flat section  182  of the raised edge  114 . When the adapter  110  is inserted into the opening  12 , the “O” ring  130  is positioned between the connecting surface  116  of the raised edge  114  and the wall of the housing  10 . Due to the sleeve ring  16  extending from the housing  10 , it is not possible to see the “O” ring  130  from the side, and additionally, the capacity of the seal of the connector system  100  to resist lateral loading is improved. 
       FIG. 10  is yet another sectional view showing various aspects of the connector system  100 . As mentioned above, in certain embodiments of this connector system  100 , it is arranged in a manner allowing connection of optical cables. In the embodiment shown in  FIG. 10 , the locking ring  120  interacts with the adapter  110  to tightly secure the connector system  100  within the opening  12  in the housing  10 . The “O” ring  130  is compressed between the connecting surface  116  of the raised edge  114  and the outer side wall of the housing  10 , the connecting surface  122  of the locking ring  120  connecting with the inner side wall of the housing  10 . As shown in the drawings, where the locking ring  120  has already been rotated until the first locking component  140  and second locking component  150  connect, the connecting surfaces  116  and  122  are positioned at a pre-set distance allowing satisfactory compression of the “O” ring  130 . 
     The first end of the adapter  110  contains a dust cap  210 , that dust cap  210  being sealed by the “O” ring  212 . 
     In this manner, the adapter  110  remains sealed until the adapter is used to connect the housing  10  to external optical cables, and as such, it is possible to include a dust cap strap  214  to retain the dust cap  212 . The adapter body  112  contains an internal adapter  216 , that internal adapter  216  possessing a protruding section  218  extending through the opening  144  of the protruding locking sections  140   a  and  140   b  of the first locking component  140 . One end of the internal adapter  216  is contained within the retention sections  220  and  222  of the retention sleeve tube  224 , the opposite end of said internal adapter containing the optical fibre connector  230 . 
     Referring back to  FIGS. 4 and 5 , the locking ring  120  possesses a hexagonal shape making rotation of the locking ring  120  convenient using a spanner. For convenience of installation in restricted spaces, holes  170  extend axially into the end of the locking ring  120  opposite to the connecting surface  122 . These holes  170  are provided such that the dowel pins of installation tool  240  fit into them.  FIG. 11  depicts an embodiment of the installation tool  240 , that installation tool  240  comprising a cylindrical body  242  with dowel pins  244 , those dowel pins  244  extending axially from the cylindrical body  242 . The dowel pins  244  are constructed such that they fit into holes  170  in the locking ring  120 . The hexagonal end section  246  is designed in relation to the dowel pins  244  in a manner that, when the dowel pins  244  are fitted into the holes  170 , a spanner can be used to rotate the installation tool  240  and the locking ring  120 . 
       FIG. 12  is a sectional view of the connector system  100 , wherein the installation tool  240  has already been connected to the locking ring. 
     More specifically, the cylindrical body  242  delimits the opening  248  capable of containing the internal adapter  216 . The dowel pins  244  are fitted into the holes  170 , in order to allow rotation of the installation tool  240  to rotate the locking ring  120 . 
     Various modifications and alternative embodiments of the present disclosure will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure, and it is to be understood that the scope of this invention should not be unduly restricted to the embodiments indicated in the diagrams in this text. 
     LIST OF COMPONENTS 
     
         
           10  housing wall 
           12  opening in housing wall 
           14  slot 
           16  sleeve ring surrounding opening 
           100  optical fibre connector system 
           110  adapter 
           112  adapter body 
           114  ring-shaped raised edge 
           116  first connecting surface 
           120  locking ring 
           122  second connecting surface 
           124  central opening in locking ring 
           126  slot in locking ring 
           128  side section of protruding locking section 
           130  “O” ring 
           140  first locking component 
           140   a  adapter protruding locking section 
           140   b  adapter protruding locking section 
           142  locking surface 
           150  second locking component 
           150   a  protruding locking section of locking ring 
           150   b  protruding locking section of locking ring 
           152  locking surface 
           154  first slanted section of locking surface 
           156  second section of locking surface 
           158  stepped section 
           160  ribbed section 
           170  holes in locking ring 
           180  adapter key 
           182  flat section of raised edge 
           210  dust cap 
           212  “O” ring 
           214  dust cap strap 
           216  internal adapter 
           218  protruding section of internal adapter 
           220  retention section 
           222  retention section 
           224  sleeve tube 
           230  optical fibre connector 
           240  installation tool 
           242  installation tool cylindrical body 
           244  installation tool dowel pin 
           246  installation tool hexagonal end section 
           248  installation tool body opening