Multi fiber optical interconnect system, with push—push type insertion/withdrawal mechanism, MT-type connector and shuttered adapter and method for using same

An optical fiber interconnect system comprising a connector for carrying an array of optical fibers along a longitudinal axis. The adapter comprises a push-push coupling mechanism configured to receive and couple with the connector upon application of a first pushing force to the connector. The connector is disengaged and may be withdrawn from the adapter upon application of a second pushing force upon the connector. The pushing forces can be applied at a pushing region by using a stylus member.Spring-biased automatic shutters are included in the adapter to provide protection against dust and other contaminants, as well as eye injuries, when only one of the connectors is inserted in the adapter. The release mechanism that disengages the connector and adapter facilitates the handling of a small connector. When the release is operated, the separation of the connector and adapter is initiated actively without the need of a strong pull.

FIELD OF INVENTION

The invention relates to fiber optics or fiber optical interconnect systems and, more particularly, to a multi-fiber optic interconnect system consisting of fiber connectors and corresponding adapters for the precise end-to-end mating of fiber optic cables. More particularly, the invention further relates to an MT-type interconnect system consisting of fiber optic connectors and corresponding adapters with a “push-push” insertion/withdrawal mechanism and a method for using the same.

BACKGROUND OF INVENTION

In the fiber optics field, the need frequently arises to connect or disconnect connectors and adapters in both single channel and multiple channel connectors and adapters. The invention here disclosed applies primarily to multiple fiber applications. There is a continuously increasing demand for higher density interconnect systems in fiber optics applications, especially in those cases where multiple fiber connectors or multiple fiber ferrules are not conveniently reachable due to small size, routing or other considerations.

In the fiber optics field, the need frequently arises to transfer light from one fiber to another either permanently or temporarily. Optical connector plugs or connectors are one of the solutions used for this purpose. Fibers terminated with optical connector plugs can be coupled together and disconnected when necessary, either to end the connection or to route the light to a different fiber. Optical connector plugs can be of the single or multiple fiber variety. Single fiber connector plugs (simplex connector plugs) provide the connection of only one fiber to another single fiber. In multiple fiber connector plugs, several fibers are simultaneously coupled with another set of similar fibers. The invention here disclosed applies primarily to multi-fiber applications.

Traditionally, in multi-fiber connectors, the connection is achieved by the use of MT-type ferrules. The ferrules, which may be manufactured mostly from plastic, have a number of channels of a diameter slightly larger than the optical fiber. It is appreciated that the ferrules may be manufactured from materials other than plastic including, but not limited to ceramics, metal and glass and not depart from the scope of the present invention. In use, the optical fibers are inserted into the channels and maintained fixed therein by the use of adhesives such as, but not limited to, epoxy, or mechanical clamping. The ends of the fibers are preferably made to be flat or protrude slightly from the end surfaces of the ferrule and are then terminated, generally by a polishing procedure or other means that provides a very smooth surface of optical quality.

Two connectors may be mated using an adapter. Each connector preferably comprises the ferrule and a ferrule holder. One of the two mated connectors usually has a ferrule with a pair of alignment pins, while the other connector has a ferrule with a pair of alignment holes. Modern fiber optic connectors usually have a spring mechanism that pushes the ferrules towards one another with a controlled force in order to achieve physical contact of both of the ferrules' ends, thereby improving the optical performance of the connection.

The termination or polishing of the fiber ends is a very involved and delicate procedure which results in the fiber position being either slightly below or above the ferrule end-face surface. The protrusion of the fibers from the ferrule end has to be controlled to very tight tolerances in order to avoid damage of the fiber ends when in physical contact. The pressure between fibers has to be kept in a narrow range in order to keep the glass in its elastic region and thereby prevent fiber rupture as well as preventing the movement of the fibers inside the ferrule channels (pistoning) when the two connectors are mated. It is also very important to obtain a very smooth surface free of scratches and other defects, especially in the central core section of the fiber where the light travels. In particular, since ferrule ends and fibers are preferably polished together, it is necessary to prevent released ferrule material from damaging the fiber ends during this procedure.

Keeping fiber optic connector plugs free from contaminants such as dirt or dust is also very important. Dirt or dust on fiber ends can scatter or absorb light, causing excessive loss of signal and corresponding poor system performance. Presence of contaminants inside the connector plug could cause misalignment with similar consequences. Likewise, because of the intensity of the light being transferred, it is important to shelter users from unintended viewing thereof, so as to prevent eye injury.

There is also a continuously increasing demand for higher density interconnect systems in fiber optics applications. The introduction by the present invention of a multi-fiber connector with the standard MT type ferrule has resulted in a small multi-fiber connector/adapter system with a push-push mechanism that allows for very high density configurations.

SUMMARY OF INVENTION

One object of the present invention is to provide a small footprint, multi-fiber optical interconnect system suitable for high density applications which has a push-push mechanism for quick and convenient connect/disconnect operation in an environment where it is difficult to reach and activate a conventional fiber optical interconnect system. One embodiment of the system disclosed herein comprises two miniature connectors and an adapter. The miniature connectors can handle multi-channel MT standard ferrules so as to enable the acceptance of bare and cabled fiber optics. The push-push mechanism is controlled by the connectors' internal springs as well as by two identical springs in the adapter, and works automatically when connectors are connected or disconnected to or from the interior of the adapter. In this version of the invention, pushing a first time on the connector connects the connector to the adapter, while pushing on the connector a second time serves to disconnect the connector from the adapter.

The connectors can handle standard MT ferrules in an embodiment to accept bare and cabled fiber optics. In this version of the invention, dust and laser protection shutters are located at both sides of the adapter. The shutters are preferably controlled by a spring mechanism, and open and close automatically when connectors and adapters are attached or separated. Latches are also included that keep the connection securely together, and a release mechanism that actively uncouples the connector and adapter is included in the body of the connector. The adapter also is preferably made of a material or coated so as to provide for protection from EMI (electromagnetic interference).

The adapter is designed to provide sufficient freedom to enable alignment of the ferrules during the mating or connecting process. Ideally, the goal is to provide for a floating connection of the ferrules within the adapter housing. This also is true for connectors using angle-polished ferrules which can have ends polished to a variety of angles including a preferred embodiment of about 8 degrees relative to the optical axis. The angled ends of the ferrules are the mating surfaces of the two connectors in face-to-face fashion.

In a preferred embodiment of the shuttered adapter version of the invention, an adapter shutter mechanism comprises a serpentine-shaped spring acting upon cams of shutter doors that are mounted to rotate about a vertical axis at each end of the adapter. Other types of springs and means for biasing the shutter doors into a normally closed position, such as, but not limited to, spring clips, coil springs, torsion springs and elastic materials, should be considered as being within the scope of this invention. When the adapter does not have a connector inserted in an open end, the serpentine-spring pushes against the cam of the shutter door at the open end so as to urge it into the closed position. When the connector is pushed into the open end of the adapter, the front of the connector pushes against the adapter shutter door and overcomes the force of the serpentine-spring on the adapter shutter door so as to automatically move the shutter door into the open position.

Spring loading of the ferrule inside of the connector is preferably provided by two coil springs serving to bias the ferrule forward within the connector housing; however, other types of springs and means for biasing the ferrule forward, such as, but not limited to, spring clips, torsion springs and elastic materials, should be considered as being within the scope of this invention.

Numerous other features and advantages of the present invention will become apparent from the following detailed description of the invention, the accompanying drawings and the appended claims, wherein like reference numerals refer to like parts.

DETAILED DESCRIPTION OF DRAWINGS

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and will herein be described in detail several specific embodiments, with the understanding that the present disclosure is to be considered merely an exemplification of the principles of the invention and the application is limited only to the appended claims.

Referring toFIGS. 1 through 7, there is shown one embodiment of a miniature MT type connector/adapter system with a push-push insertion/withdrawal mechanism. The miniature MT type connector/adapter system includes a male connector1, an adapter2, and a female connector3.

InFIG. 1, male connector1is shown as a structure designed for fiber optic ribbon cable with straight strain relief boot4in the position before being inserted into adapter2, and female connector3is shown as having a small strain relief boot6designed for bare ribbon when it is fully inserted into adapter2and fixed in the mated condition. Any other combinations of connector types with different gender, different boots, ferrule mode types (single and multi mode), number of channels, etc. are possible and should be considered within the scope of present invention.

FIG. 2is an isometric view of the male connector1ofFIG. 1showing a miniature MT-type ferrule7with two pins8which makes it a male connector. It also shows front housing9with two latch openings10(only one opening is visible) and a dual pin11. In addition, it shows rear housing12with pushing tab13and straight strain relief boot4. Different configurations of the boot (for example 90°, 60°, 45°, etc.) should be considered in the scope of the present invention.

FIG. 3is a partially exploded view of the connector1ofFIG. 2. It shows MT ferrule7with internal boot14which is inserted into the ferrule7from the rear. It also shows preassembled pin holder15and two alignment pins16. It should be understood that pin holder15is preassembled with pins16only in the male configuration of the connector1. If connector1should be assembled as a female configuration then alignment pins16are not installed.

Pin holder15(with or without alignment pins16) pushes or biases ferrule7straight ahead by two connector springs17. Rear housing18has two nests for springs17so they can push pin holder15and, consequently, ferrule7up to the stop (not shown) inside of the connector housing9. Rear housing18is preferably secured inside of the connector housing9by two latches19that snap into two openings10in the connector housing9(only one latch and one opening are shown). Once connected, ferrule7is spring loaded with a standard force designed for optimal contact between fibers. Rear housing18also has a tab20which is used for pushing the male connector1by pen or stylus for insertion or withdrawal when density does not allow human fingers to do that job.

In addition, rear housing18preferably has a grooved tail21which serves, together with the oval crimp tubing22, as a holding means for a fiber optic cable's aramid yarn. It should be understood that the bare ribbon version of the connector has a rear housing18without the grooved tail and no crimp tubing is present.

The male connector1also preferably has a strain relief boot4(can be of many different configurations) for use with cables or a small boot6(as shown inFIG. 1for the female connector3) for use with bare ribbons.

Referring now toFIG. 4, the adapter2is shown with two apertures23and24at its ends, where two connectors1and/or3(SeeFIG. 1) are intended to be inserted.FIG. 4also shows outer shell25which serves as a holder (i.e., it holds the various parts of the adapter together) and a cover of all the internal parts as well as an EMI shield. Adapter2also preferably has two latches5(only upper latch is visible) and two stoppers26(only upper stopper is visible) that are designed to assist in mounting the adapter on a panel (not shown) having a particular thickness. While the adapter is shown as being flangeless, it is appreciated that it may be flanged and not depart from the scope of the present invention.

FIG. 5shows an exploded view of the push-push adapter2(seeFIG. 4). In this view, two push-push mechanisms27are shown near each of the apertures23and24. Each mechanism27consists of triple prong spring clip28, flipper29, and nest30, which serves as a vertical axis about which the flipper29rotates or pivots. Also shown inFIG. 5are dual shutter mechanism31and its cover32.FIG. 5also shows the serpentine-shaped spring33which outwardly biases two cams34, each of which is respectively attached to ends of vertically mounted internal shutters35and36. Shutters in this example each have a vertical axis of rotation. When connectors1are not inserted into the receiving apertures23and24of the adapter2, spring-biased cams34are pushed by spring33and rotate so that the internal shutters35and36are in the closed position to provide protection against dust and other contaminants, as well as to prevent eye injuries due to the intensity of the light being transferred. It is appreciated that the connector may be a male connector or a female connector and not depart from the scope of the present invention.

Adapter also preferably contains a barrel containing an alignment sleeve (not shown) that can, to some extent, freely float inside of the barrel to assist in optimally aligning two ferrules being engaged in physical, end-to-end contact from two opposite sides of the adapter2.

It should be understood that dual pin11(shown onFIG. 2) is an integral part of the push-push mechanism27, since this dual pin11serves as an actuator of the mechanism27. Each triple prong spring clip28has two side arms37that keep flipper29in the middle position in line with the longitudinal axis of the adapter when the push-push mechanism27is not actuated. Triple prong spring clip28also has a horizontally positioned arm39that presses flipper29down in order to maintain its constant contact with dual pin11(seeFIG. 2) while performing push-push action during insertion and withdrawal of the connector1into or out off the adapter2. The insertion of connectors1into this engaged and retained relationship with adapter2can be accomplished by, among other things, applying a longitudinal force to tab13(seeFIG. 2) by using a stylus, pen point, paper clip end or the like.

FIGS. 6aand6bshow the flipper29in detail.FIG. 6ais an isometric view of the bottom surface of the flipper29, whileFIG. 6bis a bottom plan view of the flipper29.FIGS. 6aand6bshow that flipper29includes pin40providing a vertical axis X about which flipper29swings or pivots to the left and to the right during the push-push operation. Also shown are inclined cam surfaces41and42of projection43and inclined cam surface44of projection45which urge flipper29to swing to the left or to the right based on direct contact with dual pin11of the connector1, depending upon whether dual pin11(seeFIG. 2) moves forward or backward respectively, during either the insertion or withdrawal operation.

As further shown inFIG. 7d, V-grooved surface46of projection45reliably keeps connector1in its mating position by holding squared portion of dual pin11with the force of two internal connector springs (not shown). Cams48and49facilitate the flipper's29movement over the ramped edges50and51while the non-ramped opposite vertical sides of those edges50and51prevent flipper29from sliding back and swinging in the wrong direction during insertion or withdrawal of connector1into or from adapter2. As pushing force PP1continues to move left inFIG. 7buntil it reaches face42of projection43which as shown inFIG. 7c, acts as a stop, while flipper29rotates upwardly about axis X, which extends longitudinally through the center of pin40, as shown inFIG. 6a.

FIGS. 7athrough7fschematically show the interaction between flipper29and dual pin11during insertion and withdrawal of connector1into or from adapter2. In those diagrams, arrows FRand FLrepresent right and left biasing forces created by two side legs37of the spring clip28(seeFIG. 5). Those forces tend to keep flipper29in the neutral position when inactive. Arrows PP1represent the insertion force when connector1moves into the adapter2during the first “push” action. Arrows PCrepresent the force provided by two main connector springs (not shown inFIG. 7) which tends to either: (1) keep connector1in the mating position with the adapter2or, (2) push connector1out of the interior of adapter2after the second “push” action.

As shown inFIG. 7e, Arrow PP2represents a force of a second “push” action. Each ofFIGS. 7athrough7falso has a virtual 2 mm ruler which shows the relative position of flipper's29different elements described earlier and both square and circular elements of dual pin11during each step of the insertion and withdrawal processes.

In reference toFIGS. 7athrough7c, in operation, connection is initiated by pushing connector1in the direction of arrow PP1ofFIG. 7a, until it is received in opening24of adapter2(FIG. 4). As square portion of pin11of connector1contacts and then slides along in contact with surface44, it is guided along ramped cam surface48until it reaches the stopped position (FIG. 7c) by resting against angled surface42. Further movement of connector1into the interior of adapter2is thus prohibited. Because flipper29is free to rotate about axis X, corresponding to pin40and hole30(FIG. 5), the spring force FRprovided by the side legs37of spring clip28is overcome and flipper29rotates counterclockwise as viewed inFIG. 7b, until pin11reaches the stop position against surface42as shown inFIG. 7c. When connector1is released and no longer pushed inwardly into the interior of adapter2, biasing forces Frand F1of spring clip28tend to move flipper back to the center position ofFIG. 7d, while ramped cam surface48tends to urge pin11downwardly into the mated position so as to abut surfaces50and46as shown inFIG. 7dby capturing square portion of pin11therein.

To unmate and withdraw connector1from adapter2, connector1is again pushed inwardly along the longitudinal axis as viewed inFIGS. 7eand7fand towards the interior of adapter2. Pin11is then unseated from the mated position as follows. As inward force PP2is applied, pin11moves up ramped surface49and along surface41(so that it is no longer captured between surfaces50and46) and it slides along surface51. Once pin11is freed, connector1can then be withdrawn from adapter2. Because flipper29can rotate about axis X, the biasing force FLis overcome and flipper29rotates clockwise as viewed inFIGS. 7eand7f.

Many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described. Various modifications, changes and variations may be made in the arrangement, operation and details of construction of the invention disclosed herein without departing from the spirit and scope of the invention. The present disclosure is intended to exemplify and not limit the invention.