Double ferrule SC connector and adapter

This application is a continuation of U.S. patent application Ser. No. 08/720,764, filed Oct. 3, 1996 now U.S. Pat. No. 5,692,080.

1. Field of the Invention

This invention pertains to fiber optic connectors and adapters for coaxially connecting fiber optic cables. More particularly, this invention pertains to an adapter to accept two ferrules to double the density of connections.

2. Description of the Prior Art

Fiber optics have revolutionized telecommunications throughout the world. With the increased use of fiber optics, it is increasingly important to be able to connect and disconnect fiber optic cables from various sources. Two fiber optic cables can be optically coupled so that they are in communication with one another by using well-known SC connectors and an SC adapter thereby putting each fiber optic cable in communication with the other. The SC 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.

An example of an SC adapter and connector are shown in commonly assigned U.S. Pat. No. 5,317,663 to Beard, et al. dated May 31, 1994. In the '663 patent, the adapter is shown in FIG. 4 and the connector is shown in FIG. 3 . The disclosure of the '663 patent is incorporated herein by reference.

Fiber optic connectors are commonly organized such that two adjacent connectors and adapters perform transmit and receive functions, respectively, in the fiber optic circuit. Historically, such separate transmit and receive connectors and adapters would be positioned in close proximity. The prior art has developed so-called duplex adapters where transmit and receive connectors are joined. An example of such is a Single Mode Duplex SC and Multi Mode Duplex SC of Amp Corporation. Such prior art duplex SC connectors require a substantially increased volume over single SC connectors such as that shown in U.S. Pat. No. 5,317,663. It is desirable to increase the density of connectors in a telecommunications plant. It is the object of the present invention to provide a dual SC connector and adapter requiring no greater area than that required by the single SC connector and adapter shown in U.S. Pat. No. 5,317,663.

According to a preferred embodiment of the present invention, an optical fiber connector assembly includes a fiber optic connector and a fiber optic adapter. The connector includes a connector housing having a leading end. A first and second ferrule are contained within the connector housing. The first and second ferrules are positioned in parallel, spaced-apart alignment at the leading end. Also, the ferrules have exposed ends at the leading end of the connector housing. The connector housing includes a first mating fastener exposed on exterior sides of the connector housing. The adapter includes an adapter housing having an open end sized to slidably receive the leading end of the connector housing. The connector housing moves within the adapter housing to a full insert position. The adapter housing contains first and second parallel sleeves which are positioned to slidably receive respective ones of the first and second ferrules as the connector housing is moved to the full insert position. The adapter housing includes a second mating fastener exposed to an interior of the adapter housing to releasably mate with the first mating fastener when the connector housing is in the full insert position.

FIG. 1 is a plan view of an adapter according to the present invention coupled to a connector according to the present invention to form a connector/adapter assembly according to the present invention.

FIG. 2 is a view taken along line 2 — 2 of FIG. 1 ;

FIG. 3 is a cross-sectional longitudinal view of the assembly of FIG. 1 rotated 90° from the view of FIG. 2 ,

FIG. 4 is a front, top, and side perspective view of a connector according to the present invention;

FIG. 5 is the view of FIG. 4 with an outer housing of the connector removed to expose an interior housing;

FIG. 6 is a longitudinal cross-sectional view of the connector of FIG. 4 ;

FIG. 7 is the view of FIG. 4 rotated 90°;

FIG. 8 is a perspective view of an adapter of the present invention;

FIG. 9 is a perspective view of a first mating half of a housing of the adapter shown in FIGS. 1-3 ; and

FIG. 10 is a perspective view of a second mating half of an adapter housing containing a sleeve sub-assembly.

With reference now to the several drawing figures in which identical elements are numbered identically throughout, a description of the preferred embodiment of the present invention will now be provided.

With initial reference to FIGS. 1-3 , a fiber optic connector/adapter assembly 10 includes a fiber optic connector 12 and a fiber optic adapter 14 . Single ferrule fiber optic connectors and adapters are shown in commonly assigned U.S. Pat. No. 5,317,663 incorporated herein by reference. Such adapters include openings for receiving two connectors in order to optically couple the connectors. In FIGS. 1-3 , only a single connector 12 is shown inserted into the adapter 14 for purposes of clarity. It will be appreciated that, in use, two connectors 12 will be coupled to a single adapter 14 in order to optically couple the two connectors 12 .

The connector 12 is separately shown in FIGS. 4-7 . Shown best in FIGS. 4 and 5 , the connector 12 includes a connector housing 16 formed by an outer housing 18 slidably received over an inner housing 20 . In FIG. 5 , the outer housing 18 is not shown so that the inner housing 20 may be clearly illustrated. In FIG. 4 , 6 and 7 , the outer housing 18 is shown over the inner housing 20 .

Two ferrules 22 are contained within the inner housing 20 with the ferrules 22 mounted in parallel, spaced-apart alignment. Ends of the ferrules 22 extend beyond a leading end 16 a of the housing 16 .

Each of the ferrules 22 is mounted in a hollow ferrule hub 24 . The hubs 24 and attached ferrules 22 are slidably moveable within the inner housing 20 in a direction coaxial with the longitudinal axes of the ferrules 22 . Hubs 24 may be keyed to inner housing 20 to restrict rotation of hubs 24 .

Springs 26 surround the hubs 24 with the springs 26 urging the ferrules 22 outwardly from the leading end 16 a. Each of the ferrules 22 and springs 26 are independent such that each of the ferrules 22 is separately urged outwardly from leading end 16 a.

The inner housing 20 further includes a mandrel 28 onto which a fiber optic cable (not shown) may be attached. The fiber optic cables are not shown in the figures, but such a cable would include a narrow or thin optical fiber which would extend within the axial bore of the ferrules 22 . Such cables would also include sheathing to be secured to the mandrels 28 . A strain relief jacket 30 surrounds the mandrel 28 and is secured to the inner housing 20 .

The inner housing 20 includes opposite side walls 32 ( FIG. 5 ) having an exposed detent 34 with the two detents 34 positioned on opposite sides of the inner housing 20 . The outer housing 18 includes opposite side walls 35 ( FIG. 4 ) having cutouts 36 such that the side walls 32 and detents 34 are exposed through the side walls 35 . Therefore, the detents 34 are exposed on exterior sides of the connector housing 16 . The outer housing 18 further includes a guiding tab 38 and a knurled handle 40 . The side walls 35 further include a ramp or cam surface 42 in the region of the cutout 36 and positioned adjacent the detents 34 .

The adapter 14 is shown in FIGS. 1-3 . The adapter includes an adapter housing 46 formed of identical mating halves 46 a, 46 b. A single adapter housing mating half 46 a is shown separately in FIG. 9 . Half 46 b is separately shown in FIG. 10 . The adapter housing 46 includes side walls 60 opposing the outer side walls 32 , 35 of the outer housing 18 and inner housing 20 . Pins 47 are added to the half 46 a aligned with a hole 47 a on half 46 b so that halves 46 a, 46 b may be joined to form a complete housing 46 . The pins 47 permit alignment so that a seam between halves 46 a, 46 b may be ultrasonically welded.

The adapter 14 is symmetrical relative to a transverse axis X—X (FIG. 3 ). For purposes of this description of the preferred embodiment, a description of the side of adapter 14 to receive connector 12 (i.e., to the right of axis X—X in FIG. 3 ) will be described. It will be appreciated that the opposite side of adapter 14 (i.e., to the left of axis X—X in FIG. 3 ) is identical in construction to receive a similar connector 12 .

The adapter housing 46 includes an open end 48 sized to slidably receive the leading end 16 a of the connector housing 16 . Exterior surfaces of the outer connector housing 18 are complementarily shaped to the interior surface of the adapter housing 46 so that housing 18 is in close tolerance to housing 46 and is guided by housing 46 as housing 18 is inserted. The connector housing 16 moves toward a full insert position shown in FIGS. 1-3 along a path of travel parallel to the ferrules 22 . The housing 46 has a slot 37 to receive tab 38 .

A sleeve subassembly 50 is contained within an interior of the adapter housing 46 . The sleeve subassembly 50 includes identical mating halves 52 joined to define a flange 53 . The flange 53 is received within a mating groove 54 of the adapter housing 46 . The subassembly mating halves 52 define two parallel bores 56 formed therethrough aligned with the ferrules 22 . Two ferrule sleeves 58 are retained within the bores 56 . The sleeves 58 are positioned to slidably mate with the ferrules 22 when the connector 12 is inserted into the adapter 14 to the full insert position shown in FIGS. 1-3 .

As shown in FIGS. 2 and 3 , when a single connector 12 is inserted into the adapter 14 to the full insert position, the terminal ends of the ferrules 22 extend beyond the axis X—X. When a second connector is inserted into the opposite side of the adapter 14 , the ferrules of the second connector will abut the ferrules 22 of the first connector 12 . The springs 26 will permit the ferrules 22 to move away from axis X—X and reach an equilibrium point such that opposing ferrules will be in face-to-face abutting engagement at a part line along axis X—X. The sleeves 58 maintain the opposing ferrules in coaxial alignment such that opposing ferrules are provided with their contained optical fibers being optically aligned and coupled.

The adapter housing side walls 60 are provided with cutouts 62 . Contained within the cutouts 62 are cantilevered clips 64 . Cantilevered clips 64 are positioned to be received within the detents 34 when the connector 12 is inserted into the adapter 14 at the full insert position. Further, the cam surface 42 of outer housing 18 opposes the clips 64 Accordingly, when the outer housing 18 is moved in a parting or separating direction relative to the inner housing 20 , the cam surface 42 engages the clips 64 moving the clips 64 outwardly to free the clips 64 from the detents 34 permitting removal of a connector 12 from the adapter 14 It will be noted that by providing the cutouts 62 , the clips 64 may expand at least partly into the side walls 60 .

With respect to the structure shown in U.S. Pat. No. 5,317,663, the adapter of the prior art includes solid side walls. A sleeve subassembly includes clips contained completely within the interior of the adapter such that the clips remain completely within the interior of the adapter as the clips are deflected in response to a connector inserted into the adapter.

In the present invention, the clips 64 are moved to the exterior walls of the adapter such that the clips 64 may partially deflect into the exterior walls 60 of the adapter 14 This arrangement greatly increases the available volume within the adapter 14 such that two ferrules 22 may be inserted into the adapter 14 of the present invention while only a single ferrule could be inserted into the adapter of the prior art shown in U.S. Pat. No. 5,317,663 thereby doubling the density. Accordingly, for an adapter 14 having identical external dimensions (i.e., “footprint”) to that shown in U.S. Pat. No. 5,317,663, the present invention permits a doubling of the optical coupling within the adapter. The product of the '663 patent uses a standard 2.5 mm diameter ferrule. In the present invention, to achieve the same footprint either 1.25 mm or 2.5 mm diameter ferrules 22 can be used.

In addition to increasing the density of the optical coupling, two related fibers (i.e., namely transmit and receive fibers) can be simultaneously connected within a single adapter 14 . This facilitates the connections made by a technician since only a single connection need be made in order to couple related transmit and receive fibers whereas a single SC adapter such as that shown in U.S. Pat. No. 5,317,663 requires two such connections per related transmit and receive fibers.

From the foregoing, it has been shown how the objects of the invention have been attained in a preferred manner Namely, with the same external volume as a prior art single SC adapter shown in U.S. Pat. No. 5,317,663, applicant has modified the adapters 14 and connectors 12 to permit two fibers to be simultaneously connected in a single adapter 14 having the same external volume of the prior art single adapter. This both increases the functionality and density of fiber optic connections over the prior art.

While the invention has been disclosed in a preferred embodiment, it will be appreciated that modifications and equivalents of the disclosed concepts such as those which readily occur to one skilled in the art shall be included within the scope of the claims which are appended hereto.