WO2003076973A2

WO2003076973A2 - Single piece adapter

Info

Publication number: WO2003076973A2
Application number: PCT/US2002/033954
Authority: WO
Inventors: David Erdman; Dana Ramsey
Original assignee: Tyco Electronics Corporation
Priority date: 2001-10-23
Filing date: 2002-10-23
Publication date: 2003-09-18
Also published as: WO2003076973A3; AU2002367592A8; AU2002367592A1

Abstract

An adapter (300) comprising an integrally-formed structure comprising at least: (a) a housing (301) defining a first connector-receiving cavity (307); and (b) a first resilient latch (303) extending into the first connector-receiving cavity (307) for interengaging with a first optical connector.

Description

SINGLE PIECE ADAPTER

Reference to Related Application

This application claims priority to U.S. Provisional Application No. 60/345,323 filed on October 23, 2001, which is hereby incorporated by reference.

Field of the Invention

The present invention relates to adapters for the use with fiber optics, and more specifically relates to a single piece construction of a Multi-path Push-On (MPO) adapter.

Background of the Invention

With the increase in use of fiber optic systems, connectors have become necessary for connecting fiber optic cables together. Connecting various independent fiber optic cables can be challenging as a result of the nature of fiber optics. It is important that the optical fibers being connected are properly aligned, in both the axial and transverse directions, so that there is minimal loss of light resulting from the connection. Accordingly, connector systems have been developed to join fiber optic cables which ensure a high degree of optical coupling.

As the use of fiber optics and fiber optic connectors has expanded, there developed a need to connect larger volumes of fibers. Many ferrules used today no longer carry just a single optical fiber. Multi-fiber ferrules have been developed which can carry any number of individual fibers. The most common multi-fiber ferrules used in fiber connections are pin- fitting type ferrules— one multi-fiber ferrule has alignment pins extending outward from its face and a corresponding ferrule has alignment pin holes on its face. Two such ferrules can be coupled together form a connection, with the alignment pins fitting into the alignment holes to assure proper alignment of the fibers. Ferrules of this type are called a MT (mechanically transferrable) ferrules. To couple two MT ferrules together, a connector assembly is used. A common type of connector for use in applications where the fibers need to be coupled and uncoupled relatively frequently is the MPO (multi-path push-on) connector. The MPO connector assembly is a push-pull connector assembly. This means that when the connector is in the mated state, force applied to the fiber optic cables will not separate the connection.

However, although the connector will not separate when force is applied to the cables, it is easily uncoupled by applying force directly to the connector plugs. Because connections made using an MPO connector assembly can be quickly and easily coupled and uncoupled, the use of MPO connector assemblies has become a popular method of connecting optical fibers.

An MPO connector plug consists of an MT ferrule surrounded by two housings. As illustrated in Fig. 1, the MT ferrule 101 is located within an inner housing 103. The inner housing 103 is surrounded by an outer housing 105 which is capable of moving over the inner housing. The face of the MT ferrule 101 contains either guide pins 107 or alignment holes. For simplicity, only one plug is shown in Fig. 1 and guide pins 107 are illustrated extending outward from the forward face of the MT ferrule 101. It should be understood that the corresponding plug to which the connector plug illustrated will mate would contain corresponding alignment holes for the alignment pins 107.

To mate two corresponding MPO connector plugs, an MPO adapter 109 is used. The MPO adapter accepts an MPO connector plug in a connector receiving cavity 111 located on each end of the adapter 109. The connecter plugs extend into the adapter until the front ends of the MT ferrules mate with each other to complete the optical connection between the fibers located in each ferrule. The connector plugs are held in place by resilient latches 113 located within the adapter. Each resilient latch has a protruding tab 114 disposed on a side facing inward into the connector receiving cavity 111. This protruding tab snaps into a corresponding recess on the MPO connector plug to secure the plug in the appropriate position within the MPO adapter. This results in the faces of the MT ferrules being physically contacted to each other, with the alignment pins 107 extending into the corresponding alignment holes to assure proper fiber alignment. In this manner, the optical connection between the fibers contained within the MT ferrules is assured.

The prior art MPO adapter comprises four separate and distinct pieces. Fig. 2 shows a cross-sectional view of the MPO adapter 200 in accordance with the prior art. The adapter consists of two hermaphroditic halves; thus, for simplicity, only one half will be discussed in detail. It is understood the finished adapter is formed by combining the two halves.

Each half of the connector is formed by assembling two separate and distinct pieces. One piece is formed to create the outer portion of the adapter. The outer portion of the adapter comprises a generally rectangular housing 201. The housing is formed such that a connector receiving cavity 209 is created in the center into which an MPO connector plug can be inserted. The housing 201 contains a flange 207 which extends around the outside perimeter of the housing 201 at the end which will be at the center of the adapter once it is mated to an identical housing to form a complete adapter. There is a mounting hole 202 extending through the flange on each of the short sides of the generally rectangular housing. This mounting hole can be used to mount the finished connector assembly, and is also used to fasten the two halves of a complete MPO connector assembly together by using a rivet or clip which extends through the mounting holes 202.

A sleeve holder 203 is a second distinct piece in the prior art MPO adapter. The sleeve holder 203 is inserted inside of the housing 201 to form one-half of the finished MPO adapter. The sleeve holder 203 has a pair of radially resilient latches 205 positioned such that the radially resilient latches extend outward toward the opening of the connector receiving cavity. On the end of each radially resilient latch is a protruding tab 206 that locks into a corresponding notch on the connector plug as mentioned above.

To assemble the MPO adapter 200, a sleeve holder 203 is inserted into each of the two corresponding halves of the adapter housing 201. The sleeve 203 is shaped with a lip extending around the outer perimeter of the sleeve. There exists a groove in the housing 201 which forms a shoulder 204. The sleeve 203 slides into the housing 201 until the lip around the perimeter seats against the shoulder 204. Once two housings 201 have been fitted with two sleeves 203, the two housings are juxtaposed with the connector receiving passageways 209 of each facing outward to form the final assembled MPO adapter. The alignment pins 211 and holes 210 assure the two halves are properly positioned relative to each other. The two halves are connected to each other using the holes 202 located in the flange 207 surrounding the outer housing 201.

The MPO connector is popular in the fiber optic field for several reasons. It is easy to connect and disconnect, making it ideal for application which connecters are coupled and uncoupled frequently. The connection process is simple, as the plugs are merely inserted into the MPO adapter to form a connection. In addition, once the connector plugs are mated by inserting them into the connector adapter, the MPO connector maintains the push-pull feature previously described in that force applied to the fiber optic cable will not cause the connection to separate.

While the MPO connector is a desirable connector, it does have shortcomings. The MPO adapter comprises numerous intricate parts, resulting in a relatively complicated procedure for construction and assembly of the adapter. Hence, the cost to manufacture and assemble the MPO adapter is increased.

It has generally been considered problematic to manufacture the MPO adapter in a manner which would allow all of the necessary features to be integrated in a single piece adapter because of the physical configuration of the final assembled connector. Specifically, viewing one half of the prior art adapter shown in Fig. 2 (divided along line A-A), it is apparent that tabs 206 of the latches 205 extend into the connector-receiving cavity and thereby "constrict" the connector-receiving cavity at that point. Indeed, it is this constriction that serves to secure the connector to the adapter. This constriction, however, would also prevent a mold used to form an integral adapter from being released. This is referred to as a "trapped steel" situation.

To overcome this problem in the prior art, the sleeve and the adapter housing are made as two separate parts. As mentioned above, the sleeve is formed around a mold with a removable outer portion, allowing the tabs 206 to be formed and then the entire sleeve removed from the inner portion or core of the mold. The housing is formed in a separate operation, with a groove or shoulder 204 formed to receive the sleeve. The adapter is formed as two separate halves, thus allowing the sleeve 203 to be inserted into the housing prior to the two halves being combined to form the final adapter. This is necessary as the sleeve 203 needs to be inserted from the center of the adapter outward in order for the lip which extends around the perimeter of the sleeve to seat properly against the shoulder 204 formed on the housing 201. Two housings 201 with sleeves 203 inserted in them are then combined to form the assembled MPO adapter.

Therefore, applicants have identified a need to develop an integrally-molded adapter which avoids the trapped-steel situation mentioned above. The present invention fulfills this need among others.

Summary of the Invention

The present invention provides for a simplified adapter which avoids the complexities of prior art adapters. Specifically, the adapter of the present invention is a one-piece integrally-molded adapter having a resilient latch that extends into a connector-receiving cavity for interengaging with a connector. In developing this adapter, the applicants exploited the resiliency of the latch. That is, the resiliency of the latch is used not only during the mating of the adapter and connector (as is well known), but also during the molding process by allowing the latch to be deflected outward and to provide for the release of the mold which would otherwise be "trapped" in the molded structure. This exploitation of the resiliency of the latch during the molding process facilitates the molding of the adapter into a single integral structure.

The adapter of the present invention offers several advantages over prior art configurations. First, by reducing the number of distinct parts in the adapter, the time and expense currently associated with manufacture and assembly of the multi-component adapter is reduced. For example, it is no longer necessary to insert sleeve portions inside of the adapter housing, or to assemble the adapter from the previously assembled halves. Additionally, the features used to ensure proper alignment of the adapter components are eliminated. For example, there is no need for alignment pins, grooves, and positioning shoulders. This creates a simpler, more efficient adapter. Furthermore, there is no need to produce an adapter with an outer flange for coupling the halves together. This allows for greater flexibility and a smaller adapter can be provided if the flange is not desired. The adapter in accordance with the present invention therefore offers all of the advantages of the prior art adapter by maintaining a physical configuration similar to that of the prior art adapter, while adding the aforementioned advantages afforded as a result of the single piece construction.

Accordingly, one aspect of the present invention is an integrally-molded adapter. In a preferred embodiment, the adapter comprises an integrally-formed structure comprising at least: (a) a housing defining a first connector-receiving cavity; and (b) a first resilient latch extending into the first connector- receiving cavity for interengaging with a first optical connector.

Another aspect of the present invention is a method of forming an integrally-molded adapter. In a preferred embodiment, the method comprises: (a) defining a space of a structure with at least a first mold and a second mold, the structure comprising at least a housing having a first connector-receiving cavity and a first resilient latch extending into the first connector-receiving cavity, the first mold being disposed between a portion of the space defining the housing and the first resilient latch, and the second mold being disposed in the first connector-receiving cavity; (b) filling the space with a moldable material; (c) removing the first mold; and (d) after removing the first mold, removing the second mold, wherein during the process of removing the second mold, the first resilient latch is urged into the void left by the first mold.

Brief Description of the Drawings

Figure 1 depicts the structure of a prior art MPO connector system.

Figure 2 is a cross-sectional view of a four-piece MPO adapter shown in Figure 1. n accordance with the prior art. Figure 3 is a cross-sectional view of the single piece MPO adapter in accordance with the present invention.

Figure 4 is a cross-sectional view of both the MPO adapter and the tooling for manufacturing the MPO adapter shown as they would appear during the forming process in accordance with the present invention.

Figure 5a is an illustration of one embodiment of a finished MPO adapter in accordance with the present invention.

Figure 5b is an illustration of one embodiment of a finished MPO adapter in accordance with the present invention.

Detailed Description of the Invention

The present invention provides for a single integrally-molded adapter and a method for manufacturing it. As used herein, the term "adapter" refers to any structure configured to receive a connector in which a latch from the adapter interengages with the connector during mating. Examples of such adapters include coupling adapters (e.g., simplex, duplex and backplane interfaces) for coupling two connectors together, and connector interfaces on devices (e.g., passive devices, such as, add/drop filters, arrayed wave guide gratings (AWGs), splitters/couplers, and attenuators, and active devices, such as, optical amplifiers, transmitters, receivers and transceivers) for optically coupling a connector to the device. For purposes of illustration, the adapter of the present invention is discussed herein with respect to an MPO adapter for coupling MPO-type connectors. It should be understood, however, that the invention is not limited to this particular adapter type and that the present invention applies to any adapter which uses a resilient latch to interengage with the connector.

The single piece MPO adapter according to the present invention is illustrated in Figures 3, 4, 5a, and 5b. Referring to Fig. 3, it should be readily apparent that, aside from being integrally molded, the adapter of the present invention maintains the physical configuration of the assembled four-piece adapter used in the prior art. Accordingly, the similar details of this adapter and the prior art adapter will not be discussed herein in detail. Briefly, the single piece MPO adapter 300 has an integrally-molded structure 302 comprising a generally rectangular housing 301 which defines a connector-receiving cavity 307. Two radially resilient latches 303 are located within the housing. These latches are cantilevered and extend into the connector-receiving cavity 307 and outwardly toward the opening 306 of the connector-receiving cavity 307. On the cantilevered end of each radially resilient latch

303 is a protruding tab 305. This tab is beveled on the outward edge 308a and inward edge 308b.

When a connector plug is inserted into the connector- receiving cavity, the plug contacts the outward edge 308a of the protruding tab 305, causing the entire latch 303 to be deflected radially outward as the plug is inserted during mating. When the plug has been fully inserted, the protruding tab 305 interengages with a notch located on the connector, thereby returning to its non-deflected position and securing the connector within the adapter. When the connector is removed, the angled inner edge 308b of the protruding tab causes the resilient latch 303 to again be deflected, allowing the connector to be removed.

The method of forming the adapter of the present invention is performed using a

"two-pull" molding technique. This means that the forming mold comprises at least two components, a first mold and a second mold. Once the material forming the adapter is cured, the first mold is removed. This is the first pull of the two-pull process. After the first mold is pulled, the second mold can be pulled as the resilient latch deflects to allow its removal. This is the second pull of the two-pull process.

Referring to Figure 4, the two pull process is considered in greater detail. First, a space corresponding to the structure is defined by the first and second molds. The first mold 401 defines the inner surface 408 of the adapter housing 405 and the outer surface 407 of the resilient latch 402. These surfaces correspond to the inside of the housing and the outer edge of the sleeve portion used in the prior art. The second mold 403 forms the inner surface 404 of the resilient latch, including the angled edges 406a, 406b of the protruding tab on the end of the resilient latch. These surfaces correspond to the inner surface of the sleeve used in the prior art. Once the space is defined, a material suitable for molding is inserted in the space. Such materials are well known and, thus, will not be considered herein in detail.

When the plastic material comprising the adapter is cured, the first mold is pulled away. This process is shown on Figure 4 as the "1^st pull." Once the first mold has been pulled, a gap is created between the newly formed inside surface 408 of the adapter housing

405 and the outer surface 407 of the resilient latch 402. This gap enables the second mold to avoid becoming "trapped steel." Specifically, when the second mold is be pulled free (as shown in Fig. 5 as 2^nd pull), the resilient latches 402 are deflected into this newly created gap allowing the second mold to escape.

The beveled edges 406a, 406b of the protruding tabs 406 are key features in enabling this process to occur. As the second mold is removed, it applies pressure to the protruding tabs which were formed in a recess in the mold. The angled configuration of the inside edge 406b of the protruding tab causes the resilient latch 402 to be deflected outward, allowing the second mold to be removed freely.

Using this forming technique, the need to construct the MPO adapter with a separate sleeve insert has been eliminated. As mentioned above, the need to construct the prior art MPO housing out of four distinct pieces was a result of the need to insert the sleeve into the housing from the inside. This required the adapter to be constructed in two separate halves and then assembled to form the final connector. Because the present invention has eliminated the need for the separate sleeve insert, the adapter can now be formed as one piece instead of in two halves. The process described above is simultaneously applied to both sides of the MPO adapter according to the present invention, resulting in an adapter made of a single piece by a single forming process.

The present invention also provides for greater flexibility as adapters with or without a flange are now possible as shown in Figure 5a and Figure 5b, respectively. The prior art used holes located on the flange on the outside of the adapter housing to secure the two assembled halves to each other. Because the present invention no longer requires this final assembly step, the flange on the outside of the adapter is not necessary, although it can be useful to mount the entire connector assembly to a motherboard or other fixed carrier.

Accordingly, in Fig. 5a, the flange 501 located on the outside of the adapter housing is shown with slots 502 formed in the flange. In this embodiment, these slots provide for an efficient way to mount the adapter if desired. The embodiment illustrated in Figure 5b has eliminated the flange portion entirely. This embodiment would be preferred in applications where it is not desired to mount the adapter. The removal of the flange creates a smaller adapter that would be desirable in applications where space saving is a concern.

It should be understood that the foregoing is illustrative and not limiting and that obvious modifications may be made by those skilled in the art without departing from the spirit of the invention. Accordingly, the specification is intended to cover such alternatives, modifications, and equivalence as may be included within the spirit and scope of the invention as defined in the following claims.

Claims

What is claimed is:

1. An adapter for optically connecting at least one optical connector to a mating structure, said adapter comprising;

an integrally-formed structure comprising at least:

a housing defining a first connector-receiving cavity; and

a first resilient latch extending into said first connector- receiving cavity for interengaging with a first optical connector.

The adapter of claim 1, wherein said resilient latch is cantilevered.

3. The adapter of claim 2, wherein said resilient latch comprises a protruding tab at its cantilevered end, said protruding tab suited for interengaging with said first optical connector during mating.

4. The adapter of claim 1, wherein said connector-receiving cavity presents a substantially rectangular opening in said structure for receiving said first connector.

5. The adapter of claim 4, wherein said optical connector is an MT type connector.

6. The adapter of claim 5, wherein said MT-type connector is an MPO type connector.

7. The adapter of claim 1, wherein said adapter defines an optical axis, and said protruding tab has edges substantially normal to said optical axis, said edges being beveled.

8. The adapter of claim 1, wherein said adapter is for optically connecting two optical connectors, said adapter further comprising a second connector-receiving cavity opposed to said first connector-receiving cavity and a second resilient latch extending into said second connector-receiving cavity.

9. The adapter of claim 8, wherein said structure further comprising a mounting flange disposed on the outside of said housing.

10. The adapter of claim 8, wherein said structure does not have a mounting flange disposed on the outside of said housing.

11. A method of manufacturing an adapter comprising the steps of:

defining a space of a structure with at least a first mold and a second mold, said structure comprising at least a housing having a first connector-receiving cavity and a first resilient latch extending into said first connector-receiving cavity, said first mold being disposed between a portion of said space defining said housing and said first resilient latch, and said second mold being disposed in said first connector-receiving cavity;

filling said space with a moldable material;

removing said first mold; and after removing said first mold, removing said second mold, wherein during the process of removing said second mold, said^' first resilient latch is urged into the void left by said first mold.

11. The method of claim 10, wherein said space defines a structure having a second connector-receiving cavity with a second resilient latch extending into said second connector- receiving cavity, and wherein the step of defining said space further comprises using a third mold disposed between a portion of said space defining said housing and said second resilient latch, and the step of removing said first mold further comprises removing said third mold.

12. The method of claim 11 , wherein the step of defining said space further comprises using a fourth mold disposed in said second connector-receiving cavity, and the step of removing said second mold further comprises removing said fourth mold.

13. The method of claim 12, wherein said first and third molds are removed simultaneously.

14. The method of claim 12, wherein said second and fourth molds are removed simultaneously.