GB1563077A - Connector for light conductive cables - Google Patents

Abstract

The plug device has a bush part (11) and a plug part (12), in which there is provided in each case a retaining part (17, 22) having mutually aligned openings in which the ends of the optical fibres (15, 21) are arranged. Guide elements (18) are displaceably arranged in openings on a retaining part (17) and can be inserted into openings in the other retaining part (22), in order to align the ends of the optical fibres (15, 21) mutually. <IMAGE>

Description

PATENTS ACT, 1949 SPECIFICATION NO 1563077 The following amendments were allowed under Section 29 on 15 June 1981: Page 3, lines 30,62,65,96,103 and 112, for 60 read 18 Substitute the following for Fig 7 on Sheet 1 of drawings, Fig 5a on Sheet 2 of drawings and Fig Sb on Sheet 3 of drawings

(54) CONNECTOR FOR LIGHT CONDUCTIVE CABLES (71) We, BUNKER RAMO CORPO RATION, a Corporation organised and existing under the laws of the State of Delaware, United States of America, of 900 Commerce Drive, Oak Brook, Illinois, United States of America, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention is directed to a connector for light conductive elements which provides improved and more consistent coupling of light between the elements.

In recent years fiber optic light transmission systems, wherein a single optically conductive fiber or a multiplicity of parallel optically-conductive fibers are arranged to form a flexible light-conductive cable bundle for conveying light from one location to another, have come into increasing use not only for providing illumination but also for conveying data from one location to another.

In the latter application a light source is modulated with data to be transmitted to one end of the cable bundle, and the data is recovered at the other end of the cable bundle by a photo-sensitive detector. Since the data is conveyed by a medium not subject to radio frequency interference or detection, such light transmission systems are particularly well adapted for high security applications, such as found in the data processing and military communications fields.

With the increasing use of fiber optic systems, the need has developed for a connector for connecting segments of light-conductive cable bundles with minimum detriment to the optical transmission path. Prior art connectors for this purpose have not been completely satisfactory, particularly where frequent connects and disconnects must be made under adverse environmental conditions, or where multiple fiber optic circuits must be connected in a single connector because of the difficulty of maintaining an accurate consistent alignment between the ends of coupled cable segments under such conditions. The present invention is directed to a connector which provides more accurate and consistent alignment of the terminal ends of fiber optic cable bundle elements under these conditions.

According to the present invention there is provided a connector assembly for joining the terminal ends of first and second elements of light conductive cables comprising, in combination: a receptacle including a shell having a forward mating end, and a first' recess extending rearwardly from said mating end; first terminal end support means including a first insert member disposed within said first recess for positioning the terminal end of one of said cable elements in a forwardly facing position ; a plug including a shell having a forward mating end, and a second recess extending rearwardly from said mating end; second terminal end support means including a second insert member disposed within said second recess for posi- tioning the terminal end of the other of said cable elements in a forwardly facing position exially adjacent the terminal end of said first cable element; and alignment means extending from one of said insert members into the other of said insert members when said plug and said receptacle are mated, for maintaining said terminal ends of said cable elements in axial, transverse and angular alignment with the terminal ends of the cable elements in close non-abutting relationship.

Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, of which: Figure 1 is a perspective view of a connector constructed in accordance with the invention in an unmated condition; Figure 2 is a cross-sectional view of the plug portion of the connector taken along line 2-2 of Figure 1 ; Figure 3 is a cross-sectional view of the receptacle portion of the connector taken along line 3-3 of Figure 1; Figure 4 is a perspective view, partially broken away, of a fiber optic termination pin utilized in the connector for terminating the ends of light-conductive cable bundle segments; Figure 5a is an enlarged side elevational view, partially in cross-section, of the connector in an unmated condition; Figure 5b is an enlarged side elevational view, partially in cross section, of the connector in a mated condition; Figure 6 is a perspective view of the termination pin of Figure 4 shown in conjunction with a pin removal tool ; Figure 7 is an enlarged cross-sectional view of a portion of the connector illustrating the use of the pin removal tool for removing a termination pin from the connector; Figure 8 is a perspective view of an alternate embodiment of the connector of the invention; Figure 9 is a cross-sectional view of the receptacle portion of the connector taken along line 9-9 of Figure 8; Figure 10 is a cross-sectional view of the plug portion of the connector taken along ling 10-10 of Figure 8; and Figure 11 is a side elevational view, partially broken away, of the connector of Figure 8 in a mated state.

Referring to the figures, and particularly to Figures 1-3, a connector 10 constructed in accordance with the invention includes a flange-mounted receptacle 11, and a cablemounted plug 12. Receptacle I1 could also of course be bulkhead-mounted or cablemounted as well without departing from the invention. The receptacle includes a generally sleeve-shaped metal shell 13 having a front or mating end for receiving plug 12, and a flange 14 rearwardly of the mating end for mounting the receptacle to a wall or bulkhead (not shown). Individual elements of light-conductive fiber bundle cable 15 for which interconnections are to be established by the connector enter the receptacle from the rear. A plug-receiving recess 16 extends rearwardly from the forward end of the receptacle. An insert assembly 17 positioned within shell 13 supports the projecting ends of four female fiber optic alignment sleeves 18 forming connecting assemblies associated with respective ones of light-conductive fiber bundle cable elements 15.

Plug 12 includes a generally sleeve-shaped elongated cylindrical shell having a front or mating end, and a recess 20 extending rearwardly from the front end of the plug for receiving in telescoping relationship the forward end of the receptacle shell 13. Fiber optic cable elements 21 to which interconnections are to be provided extend into the rear of the connector. A generally cylindrical insert assembly 22 dimensioned for telescop- ing insertion into recess 16 is disposed within recess 20, and includes four axiallyextending apertures 23 in which four female fiber optic connecting assemblies 24 (Figure 3) are positioned. A locking ring 25 of conventional construction is concentrically disposed over shell 19 to provide twist-lock engagement with protuberances 26 on shell 13 when the plug and receptacle are mated, in a manner well known to the art. A plurality of locating keys 27 on the side wall of insert assembly 22 coact with keyways 28 provided on the inside wall of recess 16 to assure correct orientation between the two insert assemblies.

Referring to Figures 4,5a and 5, fiber optic cables 15 and 21 may be entirely conventional in design and construction, having an outer jacket 30 and an inner light- conducting core of a single fiber of plural fibers generally designated 31. The fiber core can be constructed either of glass or a suitable plastics material, such as that marketed under the trade name Crofon by the DuPont Company. In the later instance each fiber in the core 31 may consist of a central strand of polymethyl methacrylate sheathed with a transparent polymer of lower refractive index. The outer jacket 30 can be formed from a polyethylene resin marketed under the trade name Alathon by the DuPont Company.

Referring to Figure 4, the ends of each of the light-conductive cable elements 15 and 21 are individually terminated by means of terminating pins 32. Each of these pins comprises a hollow generally cylindrical metal housing 33 having an axially extending bore 34 within which the fiber core 31 of the cable is disposed. A layer of adhesive such as epoxy 35 between the fiber core and the wall of the aperture holds the core firmly in place.

The end of the fiber core extends along the bore 34 of the terminating pin and is cut substantially flush with the open end of the termination to provide a flat optical coupling surface 36.

The housing 33 of terminating pin 32 includes a front portion of reduced diameter, and a rear portion of increased diameter, and an annular flange 37 between these two portions. Bore 34 has a corresponding front portion of reduced diameter and a corresponding rear portion of increased diamter joined by a transition of convenient angle or taper, the jacket 30 of the fiber optic cable abutting the tapered shoulder formed between these two portions.

Referring to Figures 5a and 5b, the insert assembly 17 within receptacle shell 13 is seen to consist of a disc-shaped face sealing member 40, a peripheral seal 40a, a cylindrical pin insert member 41, pin retention disc 42, and ear grommet 43, which are preferably constructed of high temperature elastomeric materials such as, for example, plastics and rubber. The face sealing member 40 includes four apertures 44 which are aligned with four apertures 45 in insert member 41, and with four apertures 46 in retention disc 42, and with four ribbed apertures 47 in grommet 43, to provide four continuous axially-extending bore-like passageways for receiving the terminal pins associated with respective ones of the four light-conducting cable segments 14.

The insert assembly 22 within the shell 19 of plug 12 is seen to include a cylindrical insert member 50, a retention disc 51, and a grommet 52 (Figure 5b). The insert member 50 includes an apertues 53 which is aligned with an aperture 54 in retention disc 51, and with an aperture 55 in grommet 52 to form a continuous axially-extending passageway for receiving terminal pins associated with respective ones of the four light-conducting cable segments 21.

In accordance with the invention, accurate alignment between the terminal pins associated with respective fiber optic cables 15 and the terminal pins associated with corresponding ones of fiber optic cables 21 is maintained by means of sleeves 60 positioned within the passageways formed in insert assembly 17.

The alignment sleeves, which may be formed from metal or similar rigid material, are snugly received within these apertures.

The sleeves are resiliently held in place during insertion or removal of plug 12 by means of annular flanges 61 on the outside surfaces of the sleeves. Referring specifically to Figure 5a, the sleeve is allowed some resi- lient axial movement upon mating by virtue of the flange 61 being captured in recess 62 formed in the elastomeric material of face seal member 40. Thus, when terminal cable ends are brought together, tines 63 push against the rear of ring 37, the front of ring 37 bears tightly against the end of the sleeve and the sleeve axially moves within recess 45 achieving equilibrium between similar forces associated with the other half of the mated connector pair.

The slight axial movement permits optimal alignment of both terminating ends on a per channe basis, always maintaining the proper axial separation between faces 36. This movement also allows tines 63 to be freely separated from ring 37 in the unmated condition, permitting unhindered removal of the terminating end 32 with the tool 70 of Figure 6.

The terminal pin 32 installed on the end of each of the four fiber optic cables 15 is inserted into its respective sleeve 60 from the rear, the annular flange 37 thereon abutting the rear edge of the sleeve. The inside dimensions of sleeve 60 are such that the terminating pin assembly 32 is snugly received therein and maintained in accurate alignment with respect thereto. A pair of tines 63 inwardly projecting from the wall of aperture 46 bear against rearwardly-facing surface of the annular flange to lock the terminating pin in position and foreclose axial movement thereof.

In plug 12 the terminating pin 32 of each fiber optic cable 21 is received in respective apertures 53 and 54 and locked in place by means of tines 64 which project inwardly from the walls of recess 54 against the rearwardly facing surface of the terminating pin annular flange 37. The front of the annular flange bears against a shoulder formed on the rear surface of insert member 50, thereby preventing the termination pin assembly from being pulled out during mating or unmating of the connector. Since no alignment sleeve is present in plug 12 the terminal pin assemblies associated with fiber optic cables 21 are not rigidly held in place, but rather are free to move axially and laterally to a limited extent.

When receptacle 11 and plug 12 are mated, as shown in Figure Sb, insert assembly 22 telescopes into recess 16 as the shell 19 of the plug 12 telescopes into the end of receptacle shell 13. This causes the four alignment sleeves 60 associated with receptacle 11 to extend into respective ones of the apertures 53 of insert assembly 22, in which the termination pin assemblies 32 associated with fiber optic cables 21 are disposed. As a result, the reduced diameter portions of the terminal pins associated with cables 21 are received in respective ones of sleeves 60. The resilient mounting of the termination pins in shell 19 facilitates this by enabling the pins to readily align themselves with the approaching sleeves. As the plug and receptacle become fully mated, the end faces 36 of the two terminal pin assemblies come into close, parallel, but non-abutting relationship, for high efficiency light transfer. Since the alignment sleeves 60 determine the positions of the termination pins, misalignment of the coating light transfer surfaces 36 is precluded.

In addition, when the connector is fully assemble as shown in Figure 5b, the grommets 43 and 52, the face seal 40, and the peripheral seal 40a are placed in a state of compression. As a result, the connector is completely sealed from impurities or contaminants that might be encountered in the environments where the connector is to be used.

The fiber optic terminal pin assemblies 32 associated with each fiber optic cable are removable from their respective passageways by inserting a small sleeve-shaped tool 70 into the passageways from the rear. This tool, as shown in Figure 6, serves in the case of receptacle 11 to compress tines 63 against the sidewalls of aperture 46, or, in the case of plug 12 to compress tines 64 against the sidewall of aperture 54, with the result that the pin assemblies are released and can be removed rearwardly from the connector members. This is a significant avantage since it enables individual fiber optic pins to be removed, as when correcting installation errors or replacing damaged connectors or components thereof.

An alternate arrangement for maintaining alignment between terminal pins in a shelltype connector is shown in Figures 8-11. In this embodiment a receptacle 80 is provided having an elongated shell 81 defining a recess 82 within which an insert assembly 83 is disposed having four flush-mounted fiber optic termination pin assemblies 32. The recepa- cle 80 is adapted to mate with a plug 84 having an elongated she ! ! 85 defining a recess 86 within which four additional termination pin assemblies 32 are flush mounted. The shell 85 of plug 84 is dimensioned to extend in telescoping relationship over the plug- receiving portion of shcll 81. Insert assemblies 87 and 88 similar to those provided in receptacle 11 and plug 12 are provided within receptacle 80 and plug 84 for holding the fiber optic termination pin assemblies in position.

Since the terminating pin assemblies 32 are positioned with their coupling surface 36 parallel to the exposed surfaces of the insert assemblies, the coupling surfaces of corresponding terminal pins are brought into close abutting relationship when the connector is mated, as shown in Figure 11. To maintain the accurate alignment required between coupling surfaces 36 for good efficiency, the insert assembly of the receptacle includes five axially-extending alignment pins 90 which extend into respective ones of five alignment sockets 91 provided in the surface of the insert assembly 88 of plug 84. By dimensioning these elements for a snug but non-binding engagement, the surfaces of the two insert assemblies are maintained in accurate alignment at all times during their engagement, irrespective of movement of either insert with respect to its shell.

It will be appreciated that while the invention has been shown in conjunction with connectors having round shells and four interconnections, it is also possible to practice the invention in connection with a greater or lesser number of interconnections, and with shells having other shapes and sizes, including rectangular and square crosssections.

While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made broader aspects.

Claims (15)

1. WHAT WE CLAIM ! S :- I. A connector assomhty for joining the terminal ends of first and second elements of tight conductive cabtos comprising, in combination : a recyt, ml imluding a shcli having a forward mating end, and a first recess extending rearwardty from said mating end; first terminal end support means including a first insert member disposed within said first recess for positioning the terminal end of one of said cable elements in a forwardly facing position ; a plug including a shell having a forward mating end, and a second recess extending rearwardly from said mating end; second terminal end support means including a second insert member disposed within said second recess for positioning the terminal end of the other of said cable elements in a forwardly facing position axially adjacent the terminal end of said first cable element; and alignment means extending from one of said insert members into the other of said insert members when said plug and said receptacle are mated, for maintaining said terminal ends of said cable elements in axial, transverse and angular alignment with the terminal ends of the cable elements in close non-abutting relationship.
2. 2. A connector assembly as claimed Claim 1, wherein said alignment means comprise a sleeve in which said terminal ends of said cable elements are slidably received.
3. 3. A connector assembly as claimed in Claim 2, wherein said first and second terminal end support means each include a generally sleeve-shapes terminal pin assembly disposed over the terminal end of the corresponding one of said cable elements and said pin assemblies are slidably received at opposite ends of said alignment sleeve.
4. 4. A connector assembly as claimed in Claim 3, wherein one of said terminal pins and the corresponding end of said alignment sleeve are resiliently disposed within said first insert member, and the other of said terminal pins is resiliently mounted within the second insert member.
5. 5. A connector assembly as claimed in Claim 2, wherein said first and second termi nal ends support means each include an aper ture, said apertures being axially aligned apertures, one end of said alignment sleeve extends into one of said and is resiliently mounted to the associated terminal end support means thereof, and the other end of said alignment sleeve extends into the other of said apertures and is slidably received therein when the plug and receptacle are mated.
6. 6. A connector assembly as claimed in Claim 1, wherein at least one of said terminal end support means includes a generally sleeve-shaped terminal pin assembly dis (,,-,, r fli,-t-rminql,-n (i (if th (- r (-, n (, ctive one of said cable elements and the terminal end support means includes an axially extending recess for slidably receiving said terminal pin assembly.
7. 7. A connector assembly as claimed in Claim 6, wherein said one terminal end support means includes retaining means for locking said terminal pin assembly within said axially-extending recess.
8. 8. A connector assembly as claimed in Claim 7, wherein said retaining means comprise resilient fingers disposed in the side wall of said axially-extending aperture, said fingers being displaceable from the rear of said aperture to release said terminal pin assembly.
9. 9. A connector assembly as claimed in Claim 1, wherein said alignment means comprise at least one axially-extending alignment pin disposed on one of said insert members, and a complementarily dimensioned and aligned pin-receiving socket on the other of said insert members.
10. 10. A connector assembly as claimed in Claim 9, wherein said terminal ends of the cable elements are substantially flush with the forwardly-facing surfaces of respective ones of said insert members.
11. 11. A connector assembly as claimed in Claim 1, further comprising key means for orientating said terminal ends of said receptacle and said plug in a predetermined relation.
12. 12. A connector assembly as claimed in Claim 11, wherein said key means comprises a plurality of keyways within said first recess and a corresponding plurality of locating keys on said second insert member.
13. 13. A connector assembly according to any of the preceding claims for joining the terminal ends of several pairs of elements of light conductive cables, in which the first insert member includes axially-extending passageways for receiving the terminal ends of first ones of each of said cable elements pairs in forward-facing alignment and a second axially-aligned recess extending substantially the length thereof, said shell being dimensioned for telescoping the second insert member includes second axiallyextending passageways aligned with said first passageways for receiving the terminal ends of second ones of said cable element pairs in forward-facing alignment; and a plurality of alignment members each of which extends from one of said insert members into the other of said insert members when said plug and receptacle are mated said alignment members maintaining said terminal ends of said cable elements in axial, transverse and angular alignment with said terminal ends of said cable elements in close, non-abutting relationship.
14. 14. A connector assembly as defined in Claim 13 wherein said first and second ter minal end support means each include generally sleeve-shaped terminal pin assemblies disposed over the terminal ends of the corresponding ones of said cable segments, and said alignment members each include an alignment sleeve with corresponding pairs of said pin assemblies being slidably received at opposite ends of one of said alignment sleeves.
15. 15. A connector assembly substantially as hereinbefore described with reference to the accompanying drawings.