AU2020312171B2 - Tube coupling for fibre optic cable installation - Google Patents

Abstract

A fibre optic cable connector comprising a connector body (1) with an axial through bore (8) having a connector (2) at either end for the connection of a respective tube. An annular flange (20) extends radially into the through bore, each end face of the annular flange providing a stop surface for a respective tube end. The annular flange is undercut (21) such that it is inclined so that the axial dimension of the flange increases towards the axis. A plurality of axial splines (30) on the wall of the through bore in the vicinity of the annular flange deflect the outer wall of the tube as it approaches the flange.

Description

WO wo 2021/005041 PCT/EP2020/069089

TUBE COUPLING FOR FIBRE OPTIC CABLE INSTALLATION

The present invention relates to a fibre optic cable connector for use above or below

ground.

Such connectors used in the laying of fibre optic cables. The cables are used, for example,

to provide a fibre optic cable connection from a junction box to a building such as an office

or residence in order to provide a connection for internet data.

The fibre optic cables are provided in bundles of individual fibres which can be up to

several kilometres long. The fibre bundles/cables are fed through tubes (often referred to

as ducts/microducts/conduits) which are typically 50 metres long, but can be as long as

2000 metres. A number of tubes may therefore need to be connected together in order to

support the full run of the fibre bundle.

The connectors are provided with an annular flange at a midway point along the through

bore. When feeding a fibre or fibre bundle through the connector, this is done from a

location 100's of metres or even several kilometres away. If the fibre becomes snagged,

this can create a significant problem as the cable and connector may need to be dug up to

identify the problem.

A typical prior art arrangement is depicted in Figs. 4A and 4B. A central annular stop S has

radiused corners in order to avoid any abrupt transitions which might provide stressed

concentrations which promote propagation. However, as can be seen in Fig. 4A, the

radiused corner at the radially outermost part of the stop S means that the end face of the

tube T at either end cannot fully seat on the end face of the stop S. As a result a gap G is

created between the stop S and the tube T in which the fibre F can snag as shown in Fig.

4A. The situation in Fig. 4A assumes that the end of the tube T has been cut fully square.

However, as shown in the left hand side of Fig. 4B, the situation is even worse when the

tube T has been cut at an angle. In this case, the leading edge of the tube T (shown at the

top of Fig. 4B) engages with the radiused corned and the tube T stops at this point. As can

be seen at the bottom Fig. 4B, this creates an even bigger gap G' on the opposite side of

the connector thereby creating an even bigger snagging hazard.

The present invention is directed to solving the problem of snagging.

-2- 11 Jun 2025 11 Jun 2025

Anyreference Any referencetoto or or discussion discussion of of any any document, document,act actororitem itemofofknowledge knowledgein in this this

specification specification isisincluded included solely solely forfor thethe purpose purpose of providing of providing a context a context for the for the present present

invention. invention. ItItisis notnot suggested suggestedororrepresented represented that thatany anyof ofthese thesematters matters or orany any combination combination

thereof formed thereof at the formed at the priority prioritydate datepart partofof thethe common common general knowledge,ororwas general knowledge, was known known to to 5 5 be relevant be relevant to an to an attempt attempt to solve to solve anyany problem problem with with which which this this specification specification is is concerned. concerned. 2020312171

2020312171

According According to to thethe present present invention, invention, there there is provided is provided a fibre aoptic fibrecable opticconnector cable connector according according to to claim claim 1. 1.

10 By providing 10 By providing the the undercut undercut flange, flange, the the present present invention invention ensures ensures that that the the radially radially innermost innermost

edge of the edge of the tube tube engages engageswith withthe theannular annularflange flangebefore beforethe theradially radially outermost outermostedge edge engages. Thissignificantly engages. This significantly reduces or eliminates reduces or eliminates the the gap betweenthe gap between thetube tubeand and theannular the annular flange. In flange. In the thecase case of ofaatube tubeend end which which has beencut has been cutsquare, square,the thepresence presenceofofthe theundercut undercut will eliminate will thegap eliminate the gapon on both both sides sides of tube. of the the tube. In theIncase the of case of aendtube a tube end which haswhich not has not 15 15 beenbeen cut square, cut square, the presence the presence ofundercut of the the undercut will eliminate will eliminate the the gap gap on side on one one side of the of the

tube (unless tube (unless the the tube has been tube has beencut cutatat aa very very oblique oblique angle) angle) and, and, on onthe the opposite oppositeside sideof of the the tube, the tube, the gap is significantly gap is significantlyreduced reducedas asthe theleading leadingedge edge which which has landedon has landed onthe theannular annular flangehas flange hastravelled travelled further further into into thethe connector connector than than it it would would in the in theart. prior prior art.

20 Thus, 20 Thus, by making by making a simple a simple modification modification to thetoshape the shape of theofconnector, the connector, the snagging the snagging problem problem

is is significantly significantly reduced reduced oror eliminated. eliminated.

In In order to reduce order to reduceanyany stress stress concentrations, concentrations, the interface the interface with thewith the flange annular annularandflange the and the connector body connector body is preferably is preferably radiused radiused to provide to provide a curvedatransition. curved transition. Similarly,Similarly, the the 25 innermost 25 innermost corners corners of annular of the the annular flange flange are preferably are preferably radiused radiused to provide to provide a curved a curved

transition. transition.

In In the prior art, the prior art, the inner diameter the inner diameterof of thethe flange flange is set is set to the to be be same the same as or than as or bigger bigger the than the

inner diameter inner diameter of of thethe tube tube being being inserted inserted intoconnector. into the the connector. In the case, In the present present case, preferably preferably

30 30 the the inner inner diameter diameter of the of the flange flange is is smaller smaller than than thethe inner inner diameter diameter of of thethe tube,ininuse, tube, use, inserted inserted into into the theconnector. connector. This This aspect aspect of of the theinvention inventionextends extends to toaatube tubecable cable connector connector

in in combination with combination with a tube a tube inserted inserted intoconnector, into the the connector, thediameter the inner inner diameter of the flange of the flange

being smaller being smaller than than the the inner inner diameter diameter of theof the tube. tube.

- 2A - 2A -- 11 Jun 2025 11 Jun 2025

Thisisis aa counterintuitive This counterintuitivestep step as as this this deliberately deliberately is aisdecrease a decrease in the in the minimum minimum inner inner diameter throughthe diameter through theconnector. connector.However, However, making making the the diameter diameter of flange of flange slightly slightly smaller smaller

than the than the inner inner diameter of the diameter of the tube tube in in combination with the combination with the requirement for the requirement for the innermost innermost

corners of the corners of the annular annular flange flange to to be be radiused, radiused, means that although means that althoughthe theannular annularflange flange 5 5 protrudes slightlybeyond protrudes slightly beyondthe the inner inner diameter diameter of the of thethis tube, tube, this protrusion protrusion is a curved is a curved 2020312171

2020312171

transition such transition suchthat thatanyany fibre fibre which which abuts abuts against against one of one of themost the inner inner mostofcorners corners the of the

-3- 11 Jun 2025 2020312171 11 Jun 2025

annular flange annular flange simply simply guided guided through through the opening the opening in theIf, in the flange. flange. as setIf, asabove, out set out above, a small a small

gap does gap doesarise arisebetween between the the flangeand flange and thethe end end of of thethe tube,the tube, theradiused radiused corners corners guide guide thethe

fibre away fibre from away from thethe tube tube edge. edge. It is Itfar is far better better for the for the fibrefibre to encounter to encounter the radiused the radiused corner corner of the of the annular annular flange, flange, than than an an abrupt abrupt and exposededge and exposed edgeon on thethe end end of of a tube. a tube.

5 5 2020312171

Anotherproblem Another problemwhich which arises arises ininconnectors connectorsof of thistype this typeisis caused causedbybythe thefact fact that that the the tubes tubes

are generallysupplied are generally supplied wound wound on aThis on a coil. coil.tends Thistotends to flatten flatten the tubethe tube such thatsuch it is that it is

deformed froma atruly deformed from truly circular circular shape into an shape into an oval oval shape. When shape. When thetube the tubeisisinserted insertedinto into aa connector connector in in thisoval this oval configuration configuration and abuts and abuts againstagainst the annular the annular flange, flange, its its internal internal

10 diameter 10 diameter will bewill be larger larger in one in one direction direction andinshorter and shorter in a transverse a transverse direction. Indirection. In the direction the direction

whereititisis largest, where largest,this thiswill will expose expose thethe annular annular flange flange in these in these regions regions thereby thereby providingproviding a a snagging hazard. snagging hazard.

Preferably, therefore, Preferably, therefore, a plurality a plurality of of axial axial splines splines are are provided provided on theon theofwall wall the of the through through bore bore 15 in vicinity 15 in the the vicinity of annular of the the annular flangeflange to deflect to deflect thewall the outer outer walltube of the of the tube as it as it approaches approaches the the flange. The flange. splines will The splines willengage with any engage with part of any part of the the tube tube which which has has an enlargedradius an enlarged radiusand and exert radially exert radially inward inward force force in in order order to push to push thesethese portions portions radially radially inwardly inwardly by creating by creating a a more rounded more rounded shape shape at at thethe end end of of thethe tube tube meets meets thethe annular annular flange. flange. TheThe requirement requirement for for

axially axiallyextended splines does extended splines not mean does not meanthat thatthe thesplines splineshave havetotoextend extendininpurely purelyaxially axially 20 direction. 20 direction. Instead, Instead, it is sufficient it is sufficient that that they they extendextend a reasonably a reasonably axial axial extent extent such such that they that they will exert will the inward exert the inwardforce force on on thethe tubetube as itas it approaches approaches the annular the annular flange. flange.

Thesplines The splines may mayhave havea a constant constant thickness. thickness. However, However, preferably, preferably, thethe thickness thickness of of thethe

splines increases splines increases towards towards the annular the annular flange.flange. Thisthe This allows allows theparts thinner thinner parts of the of the splines splines

25 25 awayaway from from the annular the annular flange flange effectively effectively provide provide a tapered a tapered entryentry way way into into the the splined splined

section, while section, while increased increased spline spline thickness thickness provides an increased provides an increasedcompression compression force force thethe

closer thetube closer the tubegets gets to to thethe annular annular flange. flange. The presence The presence of theallows of the splines splines a allows a

compressive forcetotobe compressive force beprovided providedtotothe thenon-circular non-circular regions regions of of the the tube. tube. However, thereis However, there is still still space spacebetween adjacent splines between adjacent splines for for the the deformed tubedmaterial deformed tubed materialto to be be pushed pushedinto intososo 30 30 thatthat the the tube tube does does not not become become stuck stuck withinwithin the connector. the connector.

This idea This idea forms forms aa second secondaspect aspectofofthe thepresent presentinvention inventionwhich whichcan can bebe defined defined in in the the

broadest senseasasa afibre broadest sense fibre optic optic cable cable connector accordingtotoclaim connector according claim12. 12.

Preferably, the body comprises an outer sleeve and an inner sleeve, the inner sleeve being

configure to receive the distal end of a respective tube; the outer wall of the inner sleeve

being generally spaced from an inner wall of the outer sleeve to define an air gap, the inner

sleeve being supported on the outer sleeve by a discrete web of material which supports

the inner sleeve and maintains the gap between the inner and outer sleeve. With this

arrangement, rather than providing a number of external ribs as in a conventional

connector, the impact protection of the present invention may provide by an inner sleeve

which is spaced from an outer sleeve to define a gap. Preferably there is more than one

web. The webs are preferably in the same radial plane. The webs are preferably axially

offset from the annular flange so as not to impair visibility into that region.

With this arrangement the need for the ribs of the prior art can be significantly reduced.

Preferably, this eliminates the need for ribs all together so that preferably, the outer face of

the connector bodies is devoid of ribs. This removes any stress concentrators at the outer

surface of the connector as well as removing any potential dirt traps.

An example of a fibre optic cable connector in accordance with the present invention will

now be described with reference to the accompanying drawings in which:

Figs. 1A-1C are cut-away perspective views of the connector showing the progressive

insertion of a tube;

Fig. 2A is a cross-sectional view of the connector body in a plane perpendicular to the main

access of the connector body through line A-A in Fig. 2B;

Fig. 2B is a cross-sectional view of the connector body in plane through the main axis of

the body through line B-B in Fig. 2A;

Fig. 2C is a view in the same plane as Fig 2A showing a second example of a connector;

Fig. 2D is a view in the same plane as Fig. 2B showing the second example;

Fig. 3 is a cross-section in the plane of Fig. 2B of the connector with tubes connected and a

fibre bundle passing through;

Fig. 3A shows the central portion of Fig. 3 in greater detail;

Fig. 3B shows a view similar to Fig. 3A, with a different configuration of tubing and without

the fibre passing through;

Figs. 4A and 4B correspond to Figs. 3A and 3B illustrating a prior art arrangement;

Fig. 5 is an exploded perspective view of the connector from one end of the connector

body;

Fig. 6A is the equivalent to Fig. 5 in non-exploded form, showing the cartridge and collet in

a first angular configuration;

Fig. 6B is a cross-section through a plane in Fig. 6A through the locking tabs;

Figs. 7A and 7B are views corresponding to Figs. 6A and 6B respectively showing the

cartridge and collet in a second angular configuration; and

Figs. 8A and 8B corresponds to Figs. 7A and 7B but show the tube in situ.

The connector comprises a connector body 1 having a generally hollow cylindrical

configuration centred on a main axis X. A connector 2 (described in greater detail below) is

provided at either end to receive and grip a tube T at each end which is sealed by an O ring

3.

The body 1 is moulded from a non-opaque plastic. The plastic must be such that it is clear

enough that a visual inspection externally of the connector allows an operator to determine

whether a fibre cable or fibre bundle F is present in the centre of the connector. Ideally, the

body should be as close to transparent as possible. However, practical considerations

mean that the body will not be truly transparent. Instead, the body is likely to translucent to

a sufficient extent that the fibre is visible. Suitable materials are polycarbonate, polystyrene,

polyester, acrylic and nylon. The body 1 is formed in a moulding process and can optionally

be be polished polished to to improve improve the the clarity clarity of of the the body. body. As As can can be be seen seen in in the the various various figures, figures, the the

outer profile of the body is a smooth configuration which is devoid of external ribs thereby

eliminating any stress concentrations and orifices for the accumulation of dirt.

WO wo 2021/005041 PCT/EP2020/069089 - 6 -

The body 1 is made up of an outer sleeve 5 and an inner sleeve 6 which are connected by

at least one web 7 as described below.

The outer sleeve 5 has an axial bore 8 which is opened at the distal end 8 and which has a

first step 10 and second step 11 which receive the connector 2 as described below.

The inner sleeve 6 is retained by the web 7 so as to form a gap 12 of generally uniform

thickness as best seen in Fig. 2A.

As will be appreciated from Figs. 2A and 2B, the web 7 extends across only a very small

part of the inner sleeve 6 so that the gap 12 is present for most of the length and

circumference of the inner sleeve 6.

Any impact on the outer sleeve 5 which occurs during the installation of the tubing, or when

the tubing is dug up for maintenance can cause deformation of the outer sleeve 5.

By providing the gap 12, the effect of any external impact on the outer sleeve 5 is isolated,

to a significant extent, from the inner sleeve 6, and hence is largely prevented from causing

any change to the diameter of the inner bore 14 of the inner sleeve 6. Initial tests show that

this design is effective in resisting external impact. Further, this can be achieved in a a manner which does not require the addition of ribs and does not require an increase in the

outer diameter of the connector.

Use of the very small size of the web 7 means that the chance of an impact being directly

transmitted from the outer sleeve 5 to the inner sleeve 6 via the web 7 is greatly reduced.

Even if this were to occur (i.e. an impact were to be applied in the vertical downward

direction in Fig. 2A at the centre point connector in Fig. 2B), the inner sleeve 6 can still

deflect by an amount equivalent to the width of the gap 12 before any stresses occur on the

inner sleeve which would have an adverse effect on the internal bore 14 of the inner sleeve

6.

In order to mould the body 1 all of the plastic required for the inner sleeve 6 is required to

pass through the webs 7, 15. This represents a reasonably significant amount of plastic

which flows into a relatively complex and narrow flow path. In order to alleviate this, we are

contemplating providing one or more additional webs 13 depicted schematically in Fig. 2A

WO wo 2021/005041 PCT/EP2020/069089 PCT/EP2020/069089 - 7 -

these are angularly offset with respect to the web 7 and may also be axially offset to ensure

that there is no point at which the inner sleeve 6 is supported on diametrically opposed

sides. The additional web 13 provide further flow paths for the plastic into the inner sleeve

during the moulding process. Multiple webs can be made weaker than a single web such

that whichever web is closest to the impact will preferentially fracture under an applied load

leaving the remaining ribs to support the inner sleeve 6.

Instead of extending in a radial sense as shown in Fig. 2A, the or each web 15 may extend

tangentially as shown in Fig. 2C, or in any other direction across the gap 12. As shown in

Fig. 2D, the webs 15 are axially offset from an annular flange 20 so that they do not impair

the visibility into this region. The outer sleeve 5, inner sleeve 6, web(s) 7 and annular

flange are preferably all moulded as a single component as illustrated.

The manner in which the connector is configured in order to avoid snagging of the fibre F

will now be described with reference to Figs. 3, 3A and 3B with Figs. 4A and 4B being used

to provide a comparison with the prior art.

Fig. 3 shows the connector body 1 with a tube T fixed and sealed in either end. Once

connected in this way, the fibre F is blown from one end through the tube T, across the

interface between the tubes and into the adjacent tube.

The tubes T abut against the annular flange 20 at a midpoint of the inner sleeve 6. The

connectors 2 and O-rings 3 broadly have the same inner diameter as the inner diameter of

the inner sleeve 6 so that, when the tube T is pushed into the body 1, it is guided into the

inner sleeve 6. The end of the tube T then abuts the annular flange 20. As best seen in

Figs. 3A and 3B, each end of the annular flange 20 is provided undercut portion 21 such

that the thickness of the annular flange 20 in the axial direction increases towards the axis

X.

As a result of this, the innermost corner 22 of the tube T is the first part of the tube T to

abut the annular flange 20. This means that there is no gap between the inner face 23 of

the tube T and the annual flange 20.

8

The undercutportion The undercut portion 21 21 is radiused is radiused as shown as shown in 3A in Figs. Figs. 3A Similarly, and 3B. and 3B. Similarly, the radially the radially

innermost corners 24 of the annular flange are radiused to present a smooth surface to the

fibre. fibre.

In comparison with the prior art arrangement shown in Fig. 4A, the elimination of the gap G

between the end of the tube T and the annular flange 20 means that there is no exposed

abrupt edge of the tube T for the fibre F to snag on.

Fig. 3B depicts the situation where the left hand tube has been cut at an angle which is

slightly oblique to a plane perpendicular to the axis X. As a result of this, the uppermost

edge 25 of the tube T enters into the undercut region 21 and seats on the annular flange

20.

By comparison with Fig. 4B it can be seen that the gap between the tube T and the annular

flange 20 is eliminated in the top half of the figure and the gap at the bottom is significantly

reduced as compared to Fig. 4B.

As will to be apparent from Figs. 3A and 3B, the radially inward extent of the annular flange

20 is greater than the inner diameter of the tube T. As a result of this, the annular flange 20

protrudes slightly inwardly beyond the inner face 23 of the tube T. From a comparison of

Figs. 3B and 4B, if it is assumed that the fibre F is fed from right to left, and in the vicinity of

the connector 1 the tip of the fibre is travelling along the lower part of the inner face 23 in

Figs. 3A and 4B, in the Fig. 3B, this will initially encounter the corner of the annular flange

20 which projects slightly beyond the inner surface 23 of the tube T. However, the fibre F

can easily ride over this curved corner and, in doing so, this deflection should push the tip

of the fibre above the exposed edge 28 of the tube T. By contrast, in Fig. 4B, annular

projection S does not protrude beyond the inner surface 23 of the tube so there is nothing

to begin to deflect the fibre F back towards the centre of the bore. Further, the gap G' in

Fig. 4B is significantly larger than the corresponding gap in Fig. 3B. This, not only is fibre

not deflected away from this gap, the presence of the large gap affords a significantly

greater opportunity for fibre to enter the gap and become snagged on the edge 28 of the

tube T.

A further feature which prevents snagging of the tube is the splined arrangement listed as

best illustrated in Figs. 1 and 2.

WO wo 2021/005041 PCT/EP2020/069089 PCT/EP2020/069089 - 9 -

As can be seen from these figures, six axially extending splines 30 are equally spaced

around the circumference of the inner sleeve 6. These are shown having a constant cross-

section in a plane perpendicular to the axis. However, they may have a thickness increases

towards the annular flange 20.

As shown in Figs. 1A and 1B, a tube T has been fed from a coil and has taken on a

flattened oval shape. As this enters the inner sleeve 6 the tube T engages with the

enlarged portions of the tube T and tend to push this back to a more circular shape as

shown in Fig. 1C.

Any number of splines may be used. However six has been found to be a reasonable

number. This allows engagement with a flattened tube which is inserted in any orientation.

A smaller number of flanges risks the possibility that the enlarged part of the tube enters

between adjacent splines. On the other hand, adding more splines increases the insertion

resistance for the tube T into the connector 1.

The splines 30 are dimensioned such that where the splines are present is slightly smaller

than the outer diameter of the tube. The splines 30 will therefore bite into the material of the

tube T in these regions. This ensures a secure and robust fit of the tube T and also

provides the maximum opportunity for the splines to reduce the eccentricity of the tube.

The arrangement of the annular flange 20 and the splines 30 has been described in the

context of the arrangement with the outer sleeve 5 and inner sleeve 6 supported by a web

7. Both the annular flange 20 and the splines 30 could, however, be employed in a

connector with a more conventional construction which does not have the inner sleeve 6.

Instead, the through bore and inner flange are formed directly in the main body. With such

an arrangement, reinforcing ribs would be provided in order to give enhanced impact

resistance. resistance.

There is, however, a synergy between the enhanced impact resistance provided by the

inner sleeve 6 and the web 7 and the arrangement of the annular flange 20. The impact

test carried out these connectors requires the connector to be subjected to an impact and

that this impact does not cause a reduction of more than 15% of the inner diameter of the

tube. As set out above, the annular flange 20 already protrudes a small amount into this

PCT/EP2020/069089 - 10 -

area. This provides an anti-snagging benefit. However, it does mean that a smaller inward

deformation of the connector in the vicinity of the annular flange 20 would fail the impact

test as we have already pre-engineered the annular flange to go some way towards

encroaching on the 15% region beyond which it will fail the test. However, because of the

enhanced ability of the sleeve 6/web 7 arrangement to resist impact, we can afford to make

the reduction in the inner diameter in order to improve the anti-snagging properties whilst

still maintaining sufficient impact resistance to reliably meet the test requirements.

The connectors 2 (one at each end of the body 1) will now be described in greater detail

with reference to Figs. 5 to 8.

The connectors 2 are formed of two components, namely a cartridge 40 and a collet 41.

The cartridge 40 has a generally annular configuration. The outer surface is provided with a

plurality of flexible metal teeth 42. The cartridge 40 is inserted into an end of the body 1

until it seats against the second step 11. The teeth 42 grip the wall of the body 1 to ensure

that the cartridge 40 is permanent retained in the body 1. At the end of the cartridge 40

adjacent to the second step 11, there is a tapered cam surface 43 which cooperates with

the collet as described below. At the opposite end, the end face of the cartridge 40 is

provided with a pair of ramped surfaces 44. Although two such surfaces are shown, there

may be a single surface or there may be more than two. Each ramp surface has a low point

45 corresponding to an unlocked configuration and a high point 46 corresponding to a

locked configuration within an inclined face 47 in between. A bump 48 is provided at the

interface between the high point 46 and the inclined face 47. A similar bump may be

provided interface between the incline face 47 and the low point 45. The low point 45

terminates at the first end stop 49 and the high point 46 terminates at a second end stop

50. 50.

Most of the features of the collet 41 are conventional. It has a collet ring 52 from which a

plurality of flexible arms 53 extend. Each arm has a head 54 at its distal end as is provided

with an inwardly projected metal tooth 55.

With a tube T inserted for example as shown in Fig. 8B, any movement tending to pull the

tube T out of the connector causes the teeth 55 to grip into the tube, this pulls the heads 54

towards the tapered cam surface 43 on the cartridge 40 deflecting the arms 53 inwardly to

WO wo 2021/005041 PCT/EP2020/069089 - 11

provide a progressively increasing gripping force on the tube T. This serves to hold the

tube T securely in place. This is the conventional manner in which a collet operates.

The adaptation provided by the present invention is the presence of a pair of cam followers

56 extending from the collet ring 52 towards the ramped surface 44 on the cartridge 40.

Although two followers 56 are shown, in practice there are as many followers 56 as there

are ramped surfaces 44. Alternatively, the cam arrangement may be inverted such that the

ramped surface(s) is/are on the collet and the follower(s) is/are on the cartridge

The collet ring 52 is also provided with a pair of tabs 57 which extend from the collet ring 52

the opposite direction to the followers 56. As shown in the drawings, the position of the tabs

57 corresponds to a number and position of the followers 56. However, this may not be the

case. The components can be offset from one another and there need not be same

number of both.

The operation of the collet will now be described with reference to Figs. 6 to 8. The position

shown in Figs. 6A and 6B is an unlocked position. In this position, the collet 41 has been

rotated such that cam followers 56 abut the first end stops 49 such that the cam followers

are at the low point 45. As will be apparent from Fig. 6B (particularly when compared with

Fig. 7B) in this position, the collet 41 has a relatively large degree of axial freedom as it can

move from the position in which the heads 54 engage with the tapered cam surface 43 all

the way to the left (with reference to Fig. 6B) in the position shown in that figure. If held in

that position by a user, the tube T can be withdrawn because the heads 54 are kept away

from the tapered inclined surface 43 such that the collet cannot grip the tube. The collet 41

is then rotated in the direction of arrow 60 into the locked position shown in Fig. 7A. In

doing so, the followers 56 moves up the inclined faces 57, over the bumps 48, providing a

tactile feel to the user that a position has been reached, and onto the high point 46.

As will be appreciated from a comparison of Fig. 6B and Fig. 7B, in the locked position

shown shown in inFig. .7B, the Fig.7B, the collet collethashas nothing likelike nothing the same the degree of freedom same degree as in Fig. of freedom as 6B insoFig. 6B so

that it cannot be moved and held into an unlocked position where the teeth 55 disengage

with the tube T. This is more apparent from Figs. 8A and 8B which show the collet in the

same locked position as in Figs. 7A and 7B but with the tube in place. Here it can be seen

how the presence of the tube pushes the heads 54 back onto the tapered cam surface 43.

12-- 11 Jun 2025 11 Jun 2025

Theonly The onlywayway to remove to remove theTtube the tube T inlocked in this this locked configuration configuration is for theisuser for to thegrasp userthe to grasp the tabs57, tabs 57,rotate rotatethe thecollet collet4141 in in thethe direction direction of arrow of arrow 61 in61 in Figs. Figs. 6A to 6A the to the unlocked unlocked position,position,

andmanually and manuallyholdhold the collet the collet in the in the position position shown shown in while in Fig 6B Fig 6B whilethe pulling pulling theoftube tube out the out of the body 1. body 1.

5 5 2020312171

2020312171

Thetube The tube T willusually T will usually be be inserted inserted with with the collet the collet 41 in41 theinunlocked the unlocked positionposition shown in shown Figs. in Figs. 6A and 6A and6B6Basasthis thisallows allowsfor for more scopefor more scope forthe thearms arms5353totobebedeflected deflectedupon upon insertionofof insertion

the tube. the tube.However, However, as be as can can beinseen seen Fig. in Fig. 7B, 7B, even in even in the the locked locked there position, position, there is a small is a small clearance between clearance between thehead the head 54 54 andand the the tapered tapered cam cam surface surface 43. Thus, 43. Thus, it isit possible is possible to to

10 insert 10 insert thethe tube tube T with T with thethe colletininthe collet the locked lockedposition. position. This This provides provides aa simple simple assembly assembly process process asas thethe user user needs needs only only to be to betotold told to insert insert theinto the tube tube theinto the collet. collet. They do They not do not need to concern need to concernthemselves themselves with with the the lockingoperation. locking operation.

Ascan As canbebe best best seen seen from from Figs. Figs. 1A to 1A toFig. C and C and Fig.collet 3, the 3, thering collet ring 52 is 52 isset axially axially back set back 15 inside 15 inside the the body body 1. However, 1. However, the tabs the tabs 57 extend 57 extend beyond beyond the the end ofend the of the1. body body 1. In this In this

position, thecollet position, the collet41 41isisprotected protected from from external external impacts impacts by the by the body 1. body 1. Further, Further, because itbecause it

is is recessed within recessed within body body 1,is, 1, it it is, to to some some extent, extent, shielded shielded from from the the soil in soil whichinthe which the cables cables

are buried.With are buried. With thisconnector, this connector, the the only only points points where where dirt candirt can potentially potentially enter internal enter internal

workingsof workings of the the connector connectorare arebetween between the the colletring collet ring 52 52 and andthe thetube tubeTTand andbetween betweenthethe

20 collet 20 collet ring ring 52 52 andand thethe body body 1. However, 1. However, these these are interfaces are interfaces where where tighttight tolerances tolerances can can be be

applied. Any applied. Any dirtentering dirt entering here here cannot cannot impairimpair the visibility the visibility of theoffibre the fibre F within F within the1.body 1. the body

Further, because Further, because of the of the rotary rotary action action required required to unlock to unlock the collet, the collet, even if even if some some dirt does dirt does

enterinto enter intothese thesegaps, gaps, this this is is unlikely unlikely to to jamjam the the collet collet 41place 41 in in place as a rotary as a rotary motion motion can can readily readily generate sufficient torque generate sufficient torquetotoovercome any such overcome any suchsticking.' sticking. ' 25 25 In In this this specification, theterms specification, the terms ‘comprises’, 'comprises', ‘comprising’, 'comprising', ‘includes’, 'includes', ‘including’, 'including', or similar or similar

terms are terms are intended intendedto to mean meana anon-exclusive non-exclusive inclusion,such inclusion, such thata amethod, that method, system system or or apparatus that comprises apparatus that comprisesa alist list of of elements doesnot elements does notinclude include those thoseelements elementssolely, solely,but but may wellinclude may well include other other elements elements not listed. not listed.

Claims (20)

13 CLAIMS:

1. A fibre optic cable connector, the connector comprising a connector body with an

axial through bore defining an axis and having a connector at either end for the connection

of a respective tube at each end;

an annular annularflange flangeextending radially extending into the radially intothrough bore, each the through end each bore, face of endthe face of the

annular flange providing a stop surface for a respective tube end, wherein the annular

flange is undercut such that it is inclined so that the axial dimension of the flange increases

towards the axis.

2. A connector according to claim 1, wherein the interface with the annular flange and

the connector body is radiused to provide a curved transition.

3. 3. A connector according to claim 1 or claim 2, wherein the innermost corners of the

annular flange are radiused to provide a curved transition.

4. A connector according to any preceding claim, wherein the inner diameter of the

flange is smaller than the inner diameter of the tube, in use, inserted into the connector.

5. 5. A connector according to any preceding claim, wherein a plurality of axial splines

it are provided in the vicinity of the annular flange to deflect the outer wall of the tube as it

approaches the flange.

6. A connector according to claim 5, wherein the thickness of the splines increases

towards the annular flange.

7. 7. A connector according to any preceding claim, wherein the body comprises an

outer sleeve and an inner sleeve, the inner sleeve being configure to receive the distal end

of a respective tube; the outer wall of the inner sleeve being generally spaced from an inner

wall of the outer sleeve to define an air gap, the inner sleeve being supported on the outer

sleeve by a discrete web of material which supports the inner sleeve and maintains the gap

between the inner and outer sleeve.

8. 8. A connector according to any preceding claim, wherein the outer face of the

connector bodies is devoid of ribs.

14 - - 11 Jun 2025 11 Jun 2025

9. 9. A connector A connectoraccording accordingtotoany anypreceding preceding claim,wherein claim, wherein thethe connector connector body body is is moulded froma anon-opaque moulded from non-opaque plastic. plastic.

10. 10. A connector A connector according according to preceding to any any preceding claim,claim, wherein wherein each each end endofface face the of the 5 5 annular flange annular flange is is undercut. undercut. 2020312171

2020312171

11. 11. A connector A connector according according to preceding to any any preceding claim,claim, wherein wherein the annular the annular flangeflange is is moulded integrally with moulded integrally with the the connector body. connector body.

10 10 12.

12. A fibre A fibre optic optic cable cable connector, connector, thethe connector connector comprising comprising a connector a connector body body with with an an axial axial through through bore bore defining defining an an axis axis and having aa connector and having connectoratat either either end for the end for the connection connection

of of a a respective respective tube tube at at each each end; end;

an annular flange an annular flange extending extendingradially radially into into the thethrough through bore, bore, each each end face of end face of the the

annular flange providing annular flange providing aa stop stop surface for aa respective surface for respective tube tube end; end; and and

15 15 a plurality of a plurality of axial axial splines onthe splines on thewall wall of of the the through through borebore invicinity in the the vicinity of the of the

annular flange, annular flange, toto deflect deflect thethe outer outer wallwall of the of the tubetube as itas it approaches approaches the flange, the annular annular flange, wherein: wherein:

the innermost the cornersofof the innermost corners the annular annular flange flange are are radiused radiusedto to provide provide aa curved curved transition; and transition; and 20 20 adjacent adjacent totoboth both axial axial ends ends of the of the annular annular flangeflange andiameter an inner inner diameter of the of the annular flange annular flange is is smaller smaller than than the the innerinner diameter diameter of the of theintube, tube, use, in use, inserted inserted into into the connector. the connector.

13. 13. A connector A connector according according to claim to claim 12, wherein 12, wherein the interface the interface with with the the annular annular flange flange

25 25 and and the connector the connector body body is radiused is radiused to provide to provide a curved a curved transition. transition.

14. 14. A connector A connector according according to claim to claim 12 or12 or wherein 13, 13, wherein the thickness the thickness of splines of the the splines 30 increases 30 increases towards towards the annular the annular flange. flange.

15. 15. A connector A connector according according to of to any anyclaims of claims 12 to12 to wherein 14, 14, wherein the body the body comprises comprises an an outer sleeveandand outer sleeve an inner an inner sleeve, sleeve, the inner the inner sleeve sleeve being configure being configure to receive to receive the the distal end distal end

of of a respectivetube; a respective tube; thethe outer outer wallwall of the of the inner inner sleeve sleeve being being generally generally spaced spaced from from an inner an inner

35 35 wallwall of the of the outer outer sleeve sleeve to to define define an an airair gap,the gap, theinner innersleeve sleevebeing beingsupported supported on on thethe outer outer

15 -- 11 Jun 2025 2020312171 11 Jun 2025

sleeve by aa discrete sleeve by discrete web of material web of material which which supports supportsthe theinner inner sleeve sleeveand andmaintains maintainsthe thegap gap between theinner between the innerand andouter outersleeve. sleeve.

16. 16. A connector A connector according according to claim to claim 15, wherein 15, wherein therethere are aare a plurality plurality of webs of webs which which

5 5 support theinner support the inner sleeve. sleeve. 2020312171

17. 17. A connector A connector according according to claim to claim 15 or15 or wherein 16, 16, wherein theeach the or or each web web is is axially axially offset offset

from the from the annular annular flange. flange.

10 10 18.

18. A connector A connector according according to any oftoclaims any of12claims 12wherein to 17, to 17, wherein the outerthe outer face of face the of the

connector bodies connector bodies is devoid is devoid of ribs. of ribs.

19. 19. A connector A connector according according to of to any anyclaims of claims 12 to12 to wherein 18, 18, wherein the connector the connector body body is is moulded froma anon-opaque moulded from non-opaque plastic. plastic.

15 15 20.

20. A combination A combination of a of a tube tube and aand a connector connector according according to claim to claim 4 or claim 4 or claim 12, wherein 12, wherein

the inner the innerdiameter diameterof of thethe flange flange is smaller is smaller than than the inner the inner diameter diameter of the of the tube tube into inserted inserted into the connector. the connector.