GB2351814A

GB2351814A - Optical fibre connector with snap fastened base and cover

Info

Publication number: GB2351814A
Application number: GB0009293A
Authority: GB
Inventors: Philippe Pouyez; Stephane Doit; Pierre-Henri Kayoun
Original assignee: Amphenol Socapex SA
Current assignee: Amphenol Socapex SA
Priority date: 1999-04-16
Filing date: 2000-04-17
Publication date: 2001-01-10
Anticipated expiration: 2020-04-17
Also published as: FR2792421B1; GB0009293D0; FR2792421A1; GB2351814B

Abstract

An optical connector (10, Fig.1) comprises a body having a base (12) and a cover (14), said base having a connection face 24 and a top face (18), at least two recesses (26, 28) opening out into said top face and into said connection face and extending in a direction that is orthogonal to the plane of the connection face, the recesses having a right section that is V-shaped, each recess being suitable for receiving the end portion of a respective optical conductor (61, 62); said cover having a bottom face (20) provided with a longitudinal plane bearing face (53) and with snap fastening fixing means 54, (56, Fig.3) for fixing it to said base so that said bearing face of the cover overlies said longitudinal recesses at least in the portions thereof closest to the connection face. Face 20 is separated form pegs 42,44 in use. Two housings 38,40 for receiving two centering pegs 42,44 extend parallel to recesses 26,28 and have means 50,51 forming integral portions of the base 12 to press the pegs 42,44 down against the v-shaped portions of their housings. The base 12 may have two fixing pegs (70, Fig.1) for fixing the connector eg on a printed circuit.

Description

1 2351814 A MULTI-CHANNEL OPTICAL CONNECTION DEVICE The present invention

relates to an optical connector and to a method of mounting optical conductors in the connector.

The development of optical networks for data transmission constituted by optical fibers has given rise to a corresponding development of a large number of optical components enabling such opical fibers to be interconnected or enabling such optical fibers to be 10 connected to other apparatuses having optical interfaces. Such components include, in particular, optical connectors which enable optical fibers to be connected to an apparatus or optical fibers to be connected to one another. is It will be understood that with a connector, one of the key problems lies in its ability to position the end portions of the optical fibers very accurately relative to the body of the connector and relative to the indexing members of the connector body for coupling the connector 20 with an apparatus or with another connection element. To solve that problem, proposals have been made in particular for optical connectors in which holes are provided in the body of the connector to enable end portions of optical fibers to be positioned very accurately relative to said body.

In addition, with the development of such optical networks, it is becoming necessary to have optical connectors available that are of manufacturing cost that is low as possible and that enable optical fiber end portions to be mounted on the connector body in a manner that is easy, and if possible automatic.

To resolve the problem of mounting being automatic, connectors have already been proposed in which the body is made by injection molding or by extrusion. However, in connectors of that type, the end portions of the oPtical fibers are positioned by means of orifices of very small diameter formed in the body of the connector 2 and which enable such positioning to be achieved. it will be understood that when the cable has a plurality of fibers, inserting end portions of the fibers in such orifices can be quite difficult, and in any event requires a considerable amount of time and is ill suited to implementing automatic assembly operations.

A first object of the present invention is to provide an optical connector which enables the end portions of optical fibers to be positioned Accurately while also enabling the fibers to be assembled in the connector automatically or quasi-automatically, with the connector itself still being made by injection molding of suitable plastics materials.

To achieve this object, the invention provides an optical connector comprising a body suitable for receiving the end portions of at least two optical conductors, the connector being characterized in that said body consists in a base and a cover suitable for fixing on said base, said base and said cover being made by molding, said base having'a connection face and a top face, at least two recesses opening out into said top face and into said connection face and extending in a direction that is orthogonal to the plane of the connection face and presenting a V-shaped right section, each recess being suitable for receiving the end portion of an optical conductor, and two housings opening out into said connection face and having respective centering bottom walls for receiving two centering pegs, said housings extending parallel to said recesses, each housing having means forming integral portions of said base for the purpose of pressing said pegs against said centering bottom walls; said cover having a bottom face provided with a plane longitudinal bearing face and means for fixing to said base so that said bearing face of the cover overlies said longitudinal recesses at least over the portions thereof closest to the connection face and so that it does not come into contact with said pegs when 3 said cover is fixed on said base, said base and said cover having first and second snap-faBtening means forming integral portions of the base and the cover and suitable for cc-operating to secure the cover to the base.

in addition, the action of the bottom face of the cover on the optical conductors ensures that the conductors are properly positioned in the Vsection recesses.

It will be understood that by making the connector body in two parts, it is possible to put the terminal portions of the optical fibers into place easily since the triangular section recesses for receiving them are directly accessible before the cover is put into place.

Once the fibers have been put properly into place, the cover is fixed on the base and adhesive is preferably inserted so as to keep the end portions of the optical conductors in place in their recesses.

Furthermore, because the connector body is made in two parts, it is easy to manufacture by molding while still presenting very good accuracy, particularly concerning the definition of the recesses.

Furthermore, the cover is secured to the base after the end portions of the optical f ibers have been put into place by means of snap-fastening elements which form integral portions respectively of the base and of the cover. The two parts of the connector body can thus be secured to each.other easily by means of automatic systems.

Another object of the invention is to provide a method of mounting optical conductors in an optical connector which makes it possible both to obtain a very good surface state for the ends of the optical conductors and to obtain effective mechanical linking between the connector body and the optical conductors.

4 According to the invention, this object is achieved by an assembly method which comprises the following steps; - the end portions of the optical conductors are placed in the recesses in the base in 5uch a manner that their ends project from the connection surface; - thereafter the cover is put into place on the base and is fixed thereto; - an adhesive material is inserted through the orifice of said cover; - at least the ends of the end portions of the optical conductors are polished by abrasion; and - the two centering pegs are put into place in the two housings of the base.

other characteristics and advantages of the invention will appear better on reading the following description of a preferred embodiment of the invention given as a non-limiting example. The description refers to the accompanying figures, in which:

- Figure I is a perspective view of the connector as a whole, comprising its base, its cover, and its positioning pegs; - Figure 2 is a perspective view of the base of the connector on its own; - Figure 3 is a perspective view of the cover of the connector on its own; and - Figure 4 is a section view on plane IV-IV of Figure 1.

As can be seen more particularly in Figures 1 and 4, the optical connector 10 is constituted essentially by a body 12 comprising both a base 14 and a cover 16. The base 14 has a top face 18 for co-operating with the bottom face 20 of the cover 16. In the central portion of the top face IS of the base 14 there is a substantially plane middle surface 22 which extends to the connection face 24 of the connector body. in the middle surface 22 there are formed two parallel longitudinal recesses 26 and 28 of right section in a plane parallel to the plane of the face 24 that is Vshaped. The recesses 26 and 28 open out into the connection face 24. The recesses 26 and 28 are extended towards the rear portion of the base 14 via gulleys 30 and 32 of right section greater than that of the recesses 26 and 28. Each recess is designed to receive an end portion of an optical fiber. The transverse dimensions of the recesses are such that when an optical conductor is placed therein, the top portion of the conductor projects above the surface 22.

On either side of the middle face 22 provided with the recesses 26 and 28, there are two longitudinal ribs 34 and 36 which project from the face 22 outside the set of recesses 26 and 28. The ribs 34 and 36 separate the middle face 22 from two longitudinal housings 38 and 40 for receiving removable positioning pegs 42 and 44 and connected to the connection surface 24 via respective chamfers 45. The pegs 42 and 44 serve to position the connector relative to the component with which it is to be coupled. In order to enable the pegs 42 and 44 to be positioned accurately and held in position, each of the housings 38 and 40 has two solid portions with respective references 46 and 48 that are offset in the long direction of the connector body and through which respective holes 50 and 51 are formed having top portions with a radius of curvature that is significantly greater than the radius of curvature of the right section of a peg. These top edges in the holes tend to press the positioning pegs down against the V-shaped portions of their respective housings, thereby ensuring that the pegs are accurately positioned relative to the base of the connector.

In addition, and preferably, the base 14 has two fixing pegs 70 for fixing the c onnector 10, e.g. on a printed circuit.

With reference now to the bottom face 20 of the cover 16 of the connector body, this face has a bearing surface 53 in its middle portion projecting from said bottom face 20. The width of this bearing face h is also slightly smaller than the distance h' between the ribs 34 and 36 on the base of the connector body. The cover 16 also has an orif ice 52 in its middle portion passing right through it and positioned so as to lie over the end portions of the recesses 26 and 28 when the cover is fixed on the base. As explained below, the orifice 52 is designed to receive adhesive for fixing the end portions of the optical fibers in the recesses 26 and 28. Finally, the cover 16 has snap-fastening systems 54 and 56 suitable for co-operating with the side walls 58 and is 60 of the base 14 of the connector body so as to secure the cover to the base. Longitudinal connection is provided by co-operation between the solid portions 46 and 48 and corresponding slots provided in the cover.

With reference more particularly to Figure 4, there follows a description of the preferred embodiment of the connector 10 and the method of putting the end portions 61 and 62 of the optical conductors into place.

Before the cover 16 has been put into place on the base 14, it is easy to put the end portions 61 and 62 into place in the V-shaped recesses 26 and 28 in such a manner that the ends of the optical fibers project a little from the connection face 24. The cover 16 is then put into place. During this operation, the portion 53 of the bottom face of the cover does not come into contact with the middle face 22 of the base, so the surface 53 presses the optical fibers against the angled walls of the recesses 26 and 28, thus ensuring that the optical end portions are positioned and centered in said recesses. It will be understood that each optical fiber is centered by its contacts with the V-faces of the recesses and with the face 53 of the cover, thereby constituting a "triangle". The cover is fixed to the 7 base by the snap-fastening means 54 and 56, or the like. A certain quantity of adhesive is passed through the orifice 52 of the cover so that it penetrates into the gap between the cover and the base, thereby providing a mechanical link between the optical conductors and the connector body. The ribs 36 and 34 limit spreading of the adhesive prior to setting, thereby ensuring that it does not penetrate into the housings 38 and 40 for receiving the positioning pegs 42 and 44. Because the gulleys 30 and 32 are of dimensions greater than those of the optical conductors, the coating material surrounds the optical conductors completely in this region. This provides good mechanical linking between the connector and the optical conductors-. An abrasion operation serves to polish the ends of the optical fibers 61 and 62 projecting from the connection face 24 so as to guarantee the quality of their surface states. During this operation, it is also possible to abrade a wide area of the connection face 24. The end faces of the optical conductors can be abraded so as to be orthogonal to the longitudinal axis of the connector, or so as to f orm a predetermined angle relative thereto, e.g. an angle of 82".

The abrading tool is positioned, on the basis of the four outside faces of the base of the connector. It is therefore necessary for these faces to be made with care during manufacture of the connector base, e.g. by molding. These faces are constituted by the side walls 58 and 60, the bottom face 64, and the top face 65 which comprises no more than the top portions of the side walls 58 and 60. In addition, after assembly, the top face 68 of the cover is set back from the top face 66 of the base. In the following step, the positioning pegs 42 and 44 are put into position in the housings So and 51 provided for that purpose. It should be observed that the bottom face 20 of the cover 16 does not press against the centering pegs 42 and 44, nor does it press against 8 the top faces of the ribs, thereby making it possible for the middle face 53 of the cover to act effectively on the end portions of the optical fibers 61 and 62 under the effect of the snap-fastening or the like holding the 5 cover against the base.

Because of the presence of the chamfers 45, the Vshaped bearing surfaces of the housings 38 and 40 are not in danger of being spoilt during the polishing operation.

Naturally, it would not go beyond the invention if the middle portion 22 of the top face 18 of the base of the connector body had more than two recesses of V-shaped right section so as to enable some higher number of optical fibers to be positioned and fixed in the connector.

9

Claims

CLAIMS I/ An optical connector comprising a body suitable for receiving

the end portions of at least two optical conductors, the connector being characterized in that said body consists in a base and a cover suitable for fixing on said base, said base and said cover being made by molding, said base having a connection face and a top face, at least two recesses opening out into said top face and into said connection face and extending in a direction that is orthogonal to the plane of the connection face and presenting a V-shaped right section, each recess being suitable for receiving the end portion of an optical conductor, and two housings opening out into said connection face and having respective centering bottom walls for receiving two centering pegs, said housings extending parallel to said recesses, each housing having means forming integral portions of said base for the purpose of pressing said pegs against said centering bottom walls; said cover having a bottom face provided with a plane longitudinal bearing face and means for fixing to said base so that said bearing face of the cover overlies said longitudinal recesses at least over the portions thereof closest to the connection face and so that it does not come into contact with said pegs when said cover is fixed on said base, said base and said cover having first and second snap-fastening means forming integral portions of the base and the cover and suitable for co-operating to secure the cover to the base.

2/ An optical connector according to claim 1, characterized in that said centering bottom walls of said housings are of V-shaped right section.

3/ An optical connector according to claim 2, characterized in that said means for pressing each centering peg against the centering bottom wall comprise oolid portions of!3aid baoe pierced by reapective orifices suitable for receiving corresponding ones of said pegs.

4/ An optical connector according to claim 3, characterized in that said cover has two slots, each slot being suitable for receiving the top end of one of said solid portions.

5/ An optical connector according to any one of claims 1 to 4, characterized in that said cover has an orifice extending between its top face and its bottom face and opening out into said bearing face, said orifice being designed to enable adhesive material to be put into place is on the optical conductors after they have been put into place in the body of the connector.

61 An optical connector according go claim 5, characterized in that the base of said body also has two longitudinal ribs projecting on either side of the portion of its top surface in which said longitudinal recesses open out and extending substantially parallel to said recesses, said ribs being suitable for limiting the spread of the adhesive material inserted through said orifice in the cover, so as to prevent said material from penetrating into said housings.

71 An optical connector according to any one of claims 1 to 6, characterized in that the ends of said housings open out into the connection face via chamfers.

81 A method of assembling optical conductors into a connector according to claim 5, the method being characterized in that it comprises the following steps:

- the end portions of the optical conductors are placed in the recesses in the base in such a manner that their ends project from the connection surface; 11 - thereafter the cover is put into place on the base and is fixed thereto; - an adhesive material is inserted through the orifice of said cover; - at least the ends of the end portions of the optical conductors are polished by abrasion; and - the two centering pegs are put into place in the two housings of the base.

91 A method according to claim 7, characterized in that polishing is performed so as to abrade the ends of the optical conductors and the connection face simultaneously.