GB2025649A

GB2025649A - Optic fibre connector

Info

Publication number: GB2025649A
Application number: GB7830009A
Authority: GB
Original assignee: AMP Inc
Current assignee: TE Connectivity Corp
Priority date: 1978-07-15
Filing date: 1978-07-15
Publication date: 1980-01-23
Also published as: GB2025649B

Abstract

In a connector for a plurality of optical fibre cables, a cap member 30 is releasably attached to the cable receiving end and is formed with apertures for respective cables 38. The cap member engages helical springs 40 mounted on the cables to secure ferrules 44, terminating the cables, in passageways of the connector 10 in a spring loaded condition. <IMAGE>

Description

SPECIFICATION Termination of optical fibre cables in connectors The invention relates to the termination optical fibre cables in connectors and is an improvement in the invention disclosed in our U.S. Patent 3,999,837 corresponding to U.K. patent application 51530/75 (Serial No. 1503979).

In US Patent 3,999,837 and the corresponding applications there is disclosed an optical fibre cable termination comprising a plastics ferrule having an optical fibre receiving through passageway with a fibre centering funnel section tapering towards a front end; a metal ring for crimping about the ferrule to secure the ferrule to the cable; a bush formed with a through passagway having a flared mouth at one end adapted to receive the front end of the ferrule as a force fit; a cap formed with a central passageway, and a co-operable attachment means provided on the bush and the cap, the cap being locatable on the ferrule to secure the ferrule to the bush with radial compression of the front end of the ferrule about the associated optical fibre.

Suitably the flared mouth of the bush is defined by two axially spaced annular ribs of arcuate crosssection and different radii, reducing towards the front end of the bush, and the ferrule has a tapered nose receivable as a force fit in the mouth of the bush.

In a multiple connector according to the disclosure of US patent 3,999,837, a connector body is formed with a plurality of through passagways each having flared mouth portions for receiving the front ends of respective ferrules as a force fit. Individual cap members are associated with respective through passageways to secure the ferrules to the connector body with radial compression of the front ends of the ferrules about the associated optical fibres.

A connector for individually terminating a plurality of optical fibre cables and adapted to mate with a complementary connector according to the present invention comprises a connector body having a plurality of through passageways extending from a cable receiving end to a mating face, a cap member releasably attachable to the cable receiving end, and formed with apertures for passage of respective cables, a ferrule member for each passageway adapted to be secured to a respective cable received within an axial bore, the front end of each ferrule being tapered for receipt with a force fit in a correspondingly profiled forward portion of the associated body passageway, each ferrule having a rearwardly directed shoulder, and a helical spring adapted to be mounted on each cable and compressed between the cap and the shoulder of the associated ferrule to secure the ferrule in the passageway in a spring loaded condition.

The invention will now be described by way of example with reference to the accompanying partly diagrammatic drawings, in which: Figure 1 is an exploded perspective view of a connector according to the invention; Figure 2 is a perspective view of the connector of figure 1 in assembled condition and arranged for mating with a complementary connector; Figure 3 is a sectional side elevation-of the connectors of figure 2 in mating engagement; Figure 4 is a perspective, partly exploded view of a connector having a two-part cap member; Figure 5 is an enlarged, fragmentary, exploded sectional view of parts of the two-part cap member of figure 4 prior to engagement, and Figure 6is a view similar to that of figure 5with the parts in engagement.

The connector 10 of figures 1 to 3 comprises a body 12 having a mating face 14with keying projections 16,18 and a plurality of parallel through passageways 20. The body 12 is formed at opposite sides with resilient latch arms, 22, 24 for releasable securing the connector to a complementary connector48, and adjacent the rear, cable receiving end of the body 12, uppper and lower detents 26, 28 are provided. A cap member 30 is adapted to fit over the rear of the body 12 and includes upper and lower latch arms 32,34 for snap engagement with body detents 26,28. 28. The cap member 30 is formed with a plurality of apertures 36 corresponding to the through passageways 20 of the body 12.The apertures 36 are formed as slots open at the upper side of the cap member 30 to admit lateral entry of respective optical fibre cables 38 and facilitate assembly of the connector.

Each cable 38 is terminated by a ferrule member 44 in the manner disclosed in US patent 3,999,837 and the corresponding patent applications in other countries. A stripped end of each cable 38 is. inserted through a helical spring 40 into the profiled bore of a ferrule member 44 and is secured within the ferrule by a crimping ring 46. As seen in figure 3, each passageway 20 of the body 12 is formed at its forward end by a convergent throat 54 having an arcuate surface in crnss-section, which is convex towards the passageway axis, the rear portions 52 of the passageways being of straight cylindrical form.

In assembled condition a tapered forward end of each ferrule member 44 engages the associated convergent throat 54 in a force fit under the spring loading of the associated helical spring 40 which is compressed between the cap member 30 and a shoulder on the ferrule defined by the crimping ring 46. Forward ends of the ferrule members 44 project from the mating face of the body to expose ferrule bores 42 at which the contained cable fibre or fibres terminate.

The complementary connector 48 of figures 2 and 3 comprises a transducer assembly mounted on a printed circuit board 50, and having a connector housing 56 having a mating face 58 with a plurality of apertures 60 corresponding to the passageways 20 of connector 10. Each aperture 60 has a frustoconical entry, converging away from the mating faces 58 and leading to a chamber 62 containing an optical transducer 64 electrically connected to the circuitry 68 of printed circuit board 50. The mating face 58 is suitably formed with keying slots, not shown, for receiving the keying projections 16, 18 of the connector 10, and at opposite sides is formed with detents 70 for engaging the latch arms 22 of the connector 10 in a snap fit.In connected condition the forward portions of the ferrules 44 exposed from the mating face of connector 10 are received in the frusto-conical entry portions of apertures 60 to admit engagement of the forward faces of the ferrules 44 with respective transducers 64.

It is to be understood that the connector 10 can, in similar manner, mate with complementary connectors terminating optical fibre cables to effect optical connection between complementary cables.

In the embodiment of figure 4, a modified connector 10 is provided with a two-part cap adapted also to serve as a cable clamp. The cap comprises a pair of hermaphroditic members 138, 140 each having a front face 142, l44formedwith a a peripheral flange 146, 148 around three sides formed with apertures 150, 152 for latchingly engaging the body detents 26, 28. Semicircular slots 154, 156 are formed in the fourth side of the front faces 142, 144 corresponding to the passageways in the connector body. Rearwardly of the front faces 142, 144 each cap member 138, 140 is formed with a recess 158 and at the rear of each recess 158 with a transverse rib 160. Studs 162 and apertures 164 on each member provide means for securing the two cap members together, with the ribs 160 serving to clamp and support the cables 38 entering the connector, the recesses 158 defining a cable passageway, the slots 156 defining respective passageways for the cables 38, leading to respective passageways in the connector body, and the front face 144 serving to engage and compress the helical springs and bias the ferrules 44 of the connector into the body 10.

As shown in figure 5, each stud 162 is suitably formed internally with a blind bore 168, and each aperture 164 with a narrow entry neck 170 leading to an enlarged bore 172. Engagement of the stud 162 within the aperture 164 effects resilient collapse of the walls around the blind bore 168; latchinglyto engage the stud 162 in the aperture as shown in figure 6.

Claims

1. Aconnectorforindividuallyterminating a plurality of optical fibre cables and adapted to mate with a complementary connector which comprises a connector body having a plurality of through passageways extending from a cable receiving end to a mating face, a cap member releasably attachable to the cable receiving end, and formed with apertures for passage of respective cables, a ferrule member for each passageway adapted to be secured to a respective cable received within an axial bore, the front end of each ferrule being tapered for receipt with a force fit in a correspondingly profiled forward portion of the associated body passageway, each ferrule having a rearwardly directed shoulder, and a helical spring adapted to be mounted on each cable and compressed between the cap and the shoulder of the associated ferrule to secure the ferrule in the passageway in a spring loaded condition.

2. A connector as claimed in claim 1, in which the cap member has at least one resilient latch arm for engaging a detent formed on the body in a snap fit.

3. A connector as claimed in claim 1, in which the cap member is formed with apertures open at a side of the member for lateral insertion of cables.

4. A connector as claimed in claim 1, in which the cap member comprises a pair of hermaphroditic members together forming a cable passage, each said member having a cable strain relief member extending transversely of said passage, first latching means to secure said members together, and second latching means to secure said cap member on said housing member.

5. A connector as claimed in claim 4, in which the first latching means comprises at least one projection having a blind bore therein, and a matirig recess having a narrow neck opening whereby insertion of the projection into said neck causes radial collapse of said projection and a locking grip therebetween.

6. A connector as claimed in claim 1 and substantially as described with reference to figures 1 to 3 or figures 4 to 6 of the accompanying drawings;