Abstract:
A hybrid adapter permits connection of one type of connector, such as an SC-type, with a different type, such as an ST-type connector. An alternative adapter permits connection between an SC-type connector and an FC-type connector. A main body which holds the connectors in axial alignment includes a side opening. An inner housing is configured for mating with the different type connectors. The inner housing is inserted through the side opening, which is closed off by a cover. Various parts of the adapter are common between the two disclosed style adapters.

Description:
FIELD OF THE INVENTION 
     The invention generally relates to fiber optic adapters and connectors mated to the adapters. More particularly, the present invention relates to two coaxially aligned connectors mated to an adapter, where one connector is a first type, such as an SC-type, and the other connector is a different type, such as an ST-type, or an FC-type connector. 
     BACKGROUND OF THE INVENTION 
     Fiber optics have revolutionized communications throughout the world. Fiber optics are generally thin strings of glass designed to carry light which can be grouped together. 
     With the increased use of fiber optics, it has been increasingly important to be able to connect and disconnect fiber optic cables from various sources. Two fiber optic cables can be optically coupled together so that they are in communication with one another by using well-known SC-type connectors and an adapter, thereby putting each fiber optic cable in communications with the other. The SC-type connectors are placed on the end of each cable and then plugged into the adapter. The adapter has two openings, each one designed to receive a connector. The adapter is usually fixed to a dividing member. 
     U.S. Pat. No. 5,317,663 concerns an adapter for receiving two SC-type connectors. There is a need in the art for improved adapters which are easy to manufacture, and reliable in use. There is a further need for adapters which permit joining of an SC-type connector to a different type of connector, such as an ST-type connector or an FC-type connector. There is a further need in the art for reducing manufacturing costs associated with such hybrid adapters. 
     SUMMARY OF THE INVENTION 
     According to a preferred embodiment of the present invention, an adapter is shown for connecting an SC-type fiber optic connector with a different type of fiber optic connector, such as an ST-type or an FC-type connector. The adapter includes a main body including an axial cavity extending between first and second ends. The main body further has a side opening, and an internal axial cavity including a holding arrangement for slidably receiving an inner housing which is slidably inserted into the axial cavity through the side opening. A cover closes the side opening. The inner housing includes a first mating portion defining an SC mating portion positioned at the first end of the main body. The inner housing further includes a second mating portion positioned at the second end of the main body, and defining a mating portion matable with the housing of a different type connector, such as the ST-type or FC-type connector. 
     In one preferred embodiment, the first mating portion of the inner housing includes a first mating half including a cylindrical member for holding a ferrule, and a projecting clip for engaging the housing of an SC-type connector. The inner housing preferably includes a second mating half matable with the first half, and also including a cylindrical member for holding a ferrule of the second connector. A split sleeve is positioned between the first and second mating halves within the cylindrical members. Each of the first and second mating halves includes a flange. Both flanges are slidably received in a groove inside the main body of the adapter. The second mating portion of the inner housing includes a cylindrical member with either external threads for receiving an FC-type connector, or bayonets for receiving an ST-type connector. The second mating portion preferably includes an alignment feature. 
     The present invention also relates to a method of assembly wherein an inner housing configured to mate with different types of connectors is slidably inserted into a housing through a side opening, and subsequently enclosed with a cover the side opening. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front perspective view of a first embodiment of an adapter for mating an SC-type connector and an ST-type connector; 
     FIG. 2 is a rear perspective view of the adapter shown in FIG. 1; 
     FIG. 3 is an exploded front perspective view of the adapter shown in FIG. 1; 
     FIG. 4A is a front view of the main body of the adapter of FIG. 1; 
     FIG. 4B is a rear view of the front cover of the adapter of FIG. 1; 
     FIG. 5 is a front perspective view of a second embodiment of an adapter for mating an SC-type connector and an FC-type connector; 
     FIG. 6 is a rear perspective view of the adapter shown in FIG. 5; 
     FIG. 7 is an exploded front perspective view of the adapter shown in FIG. 5; 
     FIG. 8 is a front perspective view of a third embodiment of an adapter for mating an SC-type connector and an FC-type connector, and further including extended tabs like the adapter of FIG. 1; 
     FIG. 9 shows an exemplary SC-type connector. 
     FIG. 10 shows an exemplary ST-type connector. 
     FIG. 11 shows an exemplary FC-type connector. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to FIGS. 1-4B, a first preferred embodiment of an adapter  100  is shown configured for mating with two fiber optic connectors. Each end  102 ,  104  receives a fiber optic connector. First end  102  receives an SC-type connector. An exemplary SC connector  500  is shown in FIG.  9 . Opposite end  104  of adapter  100  is configured to receive an ST-type connector. FIG. 10 shows an exemplary ST-type connector  530 . Adapter  100  is a hybrid adapter in that two different type connectors are coaxially aligned and held to permit signal transmission between the fiber of one connector and the fiber of the other connector. 
     Referring to FIG. 9, SC-type connector  500  includes a cable  502  containing an optical fiber  504  which is held at the end by ferrule  506 . Ferrule  506  is held by housing  508  including a first inner portion  514 , and an axially slidable outer portion  516 . Housing  508  defines two slots  510  on opposite sides of housing  508 , and a key  512  orthogonal to the sides containing slots  510  used to mount connector  500  to adapter  100 . 
     Referring now to FIG. 10, ST-type connector  530  includes a ferrule  536  which holds a fiber  534  of cable  502 . Ferrule  536  is held by a housing  538  including an inner sleeve  540 , and a rotatable outer sleeve  544 . Inner sleeve  540  includes a key  542 . Outer sleeve  544  includes opposed slots  546  for receiving bayonets to mount connector  530  to adapter  100 . 
     Referring again to FIGS. 1-4B, adapter  100  includes a unitary main body  106  and an access plate or cover  108  which closes a side opening  109  in main body  106 . Adapter  100  has a central axis  116 . The fibers of the connectors are coaxially aligned with axis  116 . Adapter  100  further includes outwardly extending tabs  110 ,  112  to permit mounting to a dividing wall. Apertures  111 ,  113  are provided for receipt of a fastener, if desired. Retaining clips  114  are also provided to retain adapter  100  with a dividing wall, if desired. 
     An inner housing  120  of adapter  100  includes a plurality of mating portions including a first mating portion  122 , a second mating portion  144 , and a third mating portion  160 . First and second mating portions  122 ,  144  form mating halves which coaxially align the ferrules and the fibers of the SC and ST connectors. First mating portion  122  defines an SC mating portion for mating with an SC-type connector like connector  500  of FIG.  9 . Second mating portion  144  and third mating portion  160  define an ST mating portion for mating with an ST-type connector like connector  530  of FIG.  10 . 
     SC portion  122  of inner housing  120  includes a first flange  124  and side tabs  126  for mating with a flange  146 , and cooperating tabs  126  of second mating portion  144 . SC mating portion  122  further includes a cylindrical portion  128  having an internal lip  130 , and an axial bore  132 . SC mating portion  122  further includes two retaining clips  134  which extend in the axial direction on opposite sides of inner housing axis  178 . Second mating portion  144  includes a cylindrical portion  148  also having a lip  130 , and an axial bore  132 . SC mating portion  122  and second mating portion  144  are arranged where the flanges  124 ,  146  abut one another, and the cylindrical portions  128 ,  148  extend in opposite directions. The cylindrical portions  128 ,  148  receive an inner sleeve  140 , held by lips  130  of each cylindrical portion  128 ,  148 . Split sleeve  140  preferably includes a slot  142 , and a bore  143  coaxially aligned with axis  178  of inner housing  120 . Cylindrical portions  128 ,  148 , and split sleeve  140  form a ferrule holding bore of adapter  100  for holding an end of a ferrule of each connector mounted to adapter  100 . To assist with alignment of SC mating portion  122  and second mating portion  144 , each flange  124 ,  146  includes a half ring  150 , and a half recess  152  for mating with reciprocally shaped structures on the opposite flange. 
     Inner housing  120  further includes ST sleeve mating portion  160  defined by third mating portion  160  coaxially aligned with SC mating portion  122  and second mating portion  144 . ST sleeve mating portion  160  includes a flange  162  including two opposed flat portions  164 ,  165 . Opposed flat portion  165  includes an alignment tab  167 . A cylindrical portion  166  extends in the same direction as cylindrical portion  148  of second mating portion  144 . Cylindrical portion  166  is sized larger than cylindrical portion  148  of second mating portion  144 , so as to overlap and receive an end of cylindrical portion  148  within bore  168  of cylindrical portion  166 . An outer surface of cylindrical portion  166  is provided with two opposed bayonets  170 , and an axially extending slot  172 . Bayonets  170 , and slot  172  provide mounting structure for mounting ST-type connector  530 , the type shown in FIG.  10 . 
     Main body  106  of adapter  100  includes a front sidewall  180 , a back sidewall  182 , a right sidewall  184 , and a left sidewall  186 . Four ridges  188 ,  190 ,  192 ,  194  are positioned in each corner of axial cavity  118  adjacent first end  102 . Back sidewall  182  further includes a slot  196 . Ridges  188 ,  190 ,  192 ,  194  and slot  196  are configured for receipt of SC-type connector  500 , the type shown in FIG.  9 . Further, retaining clips  134  engage an exterior surface of the housing of SC-type connector  500 , while cylindrical portion  128  and split sleeve  140  receive a ferrule of the SC-type connector  500 . 
     Main body  106  of adapter  100  defines an axial cavity  118  accessible through side opening  109 . Axial cavity  118  receives inner housing  120 . Axial cavity  118  of main body  106  contains a plurality of ridges and grooves to hold inner housing  120  in place which in turn is used to hold each ferrule. A transversely extending groove  198  is sized for slidably receiving both flange  124  and flange  146  of the first and second mating portions  122 ,  144 . Groove  198  prevents axial movement of the first and second mating portions  122 ,  144 . A second groove  202  is positioned on an opposite side of wall  200  within axial cavity  118 . Second groove  202  receives flange  162  of ST mating portion  160 . Groove  202  has a reciprocally shaped profile for engagement with flange  162 , so as to receive flat portions  164 ,  165 , thereby preventing rotation of ST portion  160  relative to main body  106 . A hole  183  in back sidewall  182  receives tab  167  of flange  162 . This aligns slot  196  with slot  172 . 
     As shown in FIG. 4B, cover  108  includes a main body portion  204  and two grooves  198   a ,  202   a  which align with first and second grooves  198 ,  202  of main body  106 . Cover  108  is glued or ultrasonically welded, or otherwise fastened to main body  106  to close side opening  109 . If ST sleeve mating portion  160  is installed  180 ° about its axis, cover  108  engages tab  167  to prevent complete closure of cover  108  to main body  106 , thereby preventing misaligned slots  196 ,  172 . Aligned slots  196 ,  172  permit adapter  100  to be used with connectors with keyed orientations, such as connectors with angled ends or connectors that have been tuned. 
     In use, adapter  100  receives SC-type connector  500  and ST-type connector  530 , and securely holds them in coaxial alignment for signal transmission between the connectors. Key  512  of SC connector  500  is received in slot  196  of adapter  100 . Retaining clips  134  engage slots  510  of SC connector  500 . Cylindrical portion  128  and one end of inner sleeve  140  receives ferrule  506 . Opposite end  104  of adapter  100  receives ST connector  530  where ferrule  536  is received by cylindrical portion  148 , and an opposite end of inner sleeve  140 . Key  542  is received in slot  172 , and bayonet slots  546  receives bayonets  170 . 
     Referring now to FIGS. 5-7, a second preferred embodiment of an adapter  300  includes a different configuration for mating an SC-type connector  500  with an FC-type connector. An exemplary FC-type connector  560  is shown in FIG.  11 . FC-type connector  560  includes a ferrule  566  which holds a fiber  564  of cable  502 . An FC-type connector  560  differs from an ST-type connector  530  in several features. One significant difference is that a housing  568  includes a rotatable outer sleeve  570  including internal threads  572  for mating with a threaded adapter. Inner sleeve  574  holds ferrule  566  which in turn holds fiber  564 . 
     For adapter  300 , like parts have been numbered with the corresponding numbers of parts in adapter  100  shown in FIGS. 1-4B. End  302  of adapter  300  is configured and arranged for mating with FC-type connector  560 , such as shown in FIG.  11 . Adapter  300  further includes smaller retaining tabs  304 ,  306 , relative to adapter  100 . Inner housing  320  includes an SC mating portion  122 , a split sleeve  140 , a second mating portion  144 , and an FC mating portion  360 . FC mating portion  360  includes a flange  362  including opposed flat portions  364 ,  365 . Flat portion  365  includes an outwardly extending tab  367 , which is received in a hole  380  of main body  106 . FC mating portion  360  further includes a cylindrical portion  366  sized larger than cylindrical portion  148  of second mating portion  144  to overlap and receive an end of cylindrical portion  148 . An outer surface of cylindrical portion  366  includes threads  370 , and an axially extending slot  372  for mating with FC-type connector  560 . Bore  368  of cylindrical portion  366  is coaxially aligned with cylindrical portions  128 ,  126  of SC mating portion  122 , and second mating portion  144 , respectively. 
     In a like manner as with respect to adapter  100 , use of adapter  300  includes SC connector  500  securably held to adapter  300 . Opposite end  302  receives FC connector  560  where cylindrical portion  148 , and the opposite end of inner sleeve  140  receives ferrule  566 . Threads  572  threadably engage threads  370  to securably mount FC connector  560  to adapter  300 . Key  576  is received in slot  372 . 
     As can be seen, adapter  100 , and adapter  300  have several common parts, thereby providing manufacturing advantages for manufacturing and assembling an SC/ST hybrid adapter  100  or an SC/FC hybrid adapter  300 . 
     Referring now to FIG. 8, a third preferred embodiment of an adapter  400  is shown including the SC mating end  102 , and the FC mating end  302 , as shown in the adapter  300  of FIGS. 5-7, and the extended tabs  110 ,  112  of adapter  100  as shown in FIGS. 1-4B. 
     The above specification and examples provide a complete description of the manufacture and use of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the claims hereinafter appended.