AU2019456730B2 - A tube coupling - Google Patents

Abstract

A tube coupling comprising a coupling body (1) having an opened ended throughway to receive a tube (T). A collet (41) is located in the open end of the through way having a ring (52) and a plurality of flexible arms (53) extending generally axially of the ring into the throughway. The throughway has a tapered surface (43) convergent towards the open end and the collet arms have heads at their distal ends for engaging both of the tapered surface and a tube extending through the collet into the throughway to be compressed against the tube by the tapered surface with outward movement of the collet with respect of the throughway to secure the tube in the throughway. A collet lock is formed on the collet (41), the collet having a locked rotary position in which the lock holds the collet in an outward tube securing position and an unlocked rotary position in which the collet can move axially with respect to the throughway for release and engagement of a tube by the collet. One of the body (1) and the collet (41) is provided with a cam surface (46) and the other is provided with a cam follower (56), the cam surface being provided to provide the locked and unlocked positions. The invention also extends to the collet (41).

Description

PCT/GB2019/053602

- 1 -

A TUBE COUPLING

The present invention relates to a tube coupling. It has a particular application as fibre optic

cable connector for use above or below ground. However, the concept can be applied more

broadly to other types of connector.

Such fibre optic connectors are 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 are fed through tubes (often referred to as

microducts) which are typically 100 metres long, but can be as long as 500 metres. A

number of tubes therefore need to be connected together in order to support the full run of

the fibre bundle.

Because of the manner of their use, there are number of demands on a fibre optic cable

connector.

Its outer diameter must be as small as possible in order to minimise bulk as the connectors

are often grouped together in large numbers.

The connectors also need to be highly impact resistant. Cables are usually buried in the

ground and, for maintenance, they need to be dug up. This is generally done by a labourer

with a spade, and the first that the labourer will know if the presence of the cable is when it

is struck by the spade. The connectors therefore need to be sufficiently robust to resist

such an impact. In practice, they need to pass a '15J impact test'.

The connectors have a connection at either end which attaches to and retains the tube

within the connector. This is done using a collet or grab ring. This grips on the outer wall of

the tube and any movement which tends to pull the tube out the connector causes the

collet to tighten its grip on the tube in a well-known manner. In order to release the tube,

the collet can be manually displaced inwardly of the connector. This prevents the collet

from gripping the tube allowing the tube to be withdrawn from the connector.

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It It is isaarequirement requirement ofofthe thefibre fibreoptic opticcable cable connectors connectors thatcollet that the the collet must must be beinlocked locked place in place

to prevent to accidental prevent accidental release release of tube. of the the tube.

This is This is conventionally conventionally done using aa locking done using locking clip clip which which clips clipsbetween the end between the of the end of the body of body of

5 5 the the connector connector and and a collet a collet ringring thereby thereby preventing preventing axial axial movement movement between between theand the body body and 2019456730

the collet. the collet.

Theseclips These clips have haveaanumber numberof of drawbacks. drawbacks. They They are are flimsy flimsy and and exposed exposed components components and and often break. often break. Because theyare Because they areexposed, exposed, they they become become clogged clogged with with dirt dirt making making them them

10 potentially 10 potentially difficulty to difficulty to remove. Theycan remove. They can become become accidentally accidentally dislodged dislodged during during installation installation

and are then and are then easily easily lost lost making the connector making the connectoruseless uselessunless unlessspare spare clipsare clips arecarried. carried. The The clips clips then alsodisplaced then also displaced during during installation. installation. The The installer installer will will not necessarily not necessarily know know that thisthat this

has happened has happened as as thismay this may happen happen onlyonly whenwhen the connector the connector is covered is covered with earth. with earth.

15 15 The The present present invention invention may advantageously may advantageously addressaddress at leastatsome leastofsome theseofproblems. these problems.

Analternative An alternativewayway of locking of locking a collet a collet within within a connector a connector is disclosed is disclosed in our in our own own earlier earlier EP2131089. This EP2131089. This discloses discloses thethe idea idea ofof aa lockingring locking ringwhich whichisis rotatably rotatably mounted mounted onon the the

body. Thebody body. The bodyisisprovided providedwith withaacam camsurface surface which which cooperates cooperates withwith a cam a cam follower follower on on

20 20 the the locking locking ring. ring. Rotation Rotation between between the the bodybody andlocking and the the locking ring ring changes changes the axial the axial

separation betweenthe separation between thetwo twocomponents. components. The The endlocking end of of locking ringring abuts abuts against against the the collet collet

ring. ring. In In a a locked position,the locked position, theaxial axial separation separation between between the locking the locking ring andring body and is atbody its is at its

greatest. The greatest. engagement The engagement between between the the locking locking ringring andand the the collet collet ringprevents ring prevents axial axial

movement of the movement of the collet collet suchsuch thatcollet that the the collet cannotcannot be inwardly be inwardly displaced displaced into the into the position in position in

25 which 25 which thethe tube tube canbebereleased. can released.

Thisconnector This connectoris is notnot designed designed forwith for use useawith fibrea optic fibre cable opticconnector cable connector and, and, indeed, it indeed, it wouldbebe would unsuited unsuited to such to such a purpose. a purpose. The ring The locking locking fits ring over fits the over thesurface external external of surface the of the body. Thisadds body. This adds to the to the bulkbulk connector connector which which is is against against the requirement the requirement in a fibre in a fibre optic cable optic cable

30 connector 30 connector for the for the outer outer diameter diameter to as to be besmall as small as possible. as possible. The The locking locking ringring is exposed is exposed to to

dirt dirt such that, in such that, in use, use,dirt dirt particles particlescould couldgetget into into the the locking locking ringring and and jam jam it in itthe in locking the locking position. Further,the position. Further, thelocking locking ring ring is is also also exposed exposed to damage to damage during installation during installation and the and the maintenance operations maintenance operations which which cancan either either cause cause thethe locking locking ring ring toto fail, or fail, or become stuckinin become stuck

the locked the lockedposition. position.

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

specificationisisincluded specification included solely solely forfor thethe purpose purpose of providing of providing a context a context for the for the present present disclosure. disclosure. It Itisis notnot suggested suggestedor orrepresented represented that thatany any of 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. 2019456730

According According to to thethe present present invention, invention, there there is provided is provided a tube coupling a tube coupling according according to claim 1. to claim 1.

Withthe With thepresent present invention, invention, the the locking locking ofcollet of the the collet is nowisachieved now achieved solely bysolely by interaction interaction

10 between 10 between the the body andbody and the the collet. collet. This This eliminates eliminates the locking the locking clip clip art. of the prior of the It prior also art. It also

eliminates eliminates the the locking locking ring ringof ofEP2131089. EP2131089.

Althoughthe Although theinvention invention is is motivated by the motivated by the need needto to provide provide an animproved improved fibreoptic fibre optic cable cable connector, becauseitit provides connector, because providesimprovements improvements over over EP2131089 EP2131089 in terms in terms of theoflow theprofile low profile 15 nature 15 nature of the of the connector, connector, and and the the reduction reduction in the in the number number of components of components (as it (as it does does not not

require require a a locking locking ring) ring)it it cancan also bebe also used usedinin any ofof any thethe contexts forfor contexts which EP2131089 which was EP2131089 was

designed. designed. In In particular, particular, it itisissuitable suitablefor fora awide wide range range of plumbing of plumbing applications applications which which provide fluid communication. provide fluid communication.

20 Because 20 Because the locking the locking is done is done byinteraction by the the interaction between between the and the body bodythe and the collet, collet, the locking the locking

mechanism mechanism cancan effectivelybebeinternal effectively internalto to the the body. body. This This can canprovide provideaalow lowprofile profile design design

and also and also protect protect the the locking locking mechanism from mechanism from impact impact damage damage and from and from the ingress the ingress of dirt. of dirt.

Thecam The camsurface surfacecan can be be provided provided either either on on thethe body body or or thethe collet,but collet, butis is preferably preferably on on the the

25 body. 25 body. In this In this case, case, thethe camcam surface surface can can be moulded be moulded directly directly into into the the bodybody as part as part of the of the

body mouldingprocess. body moulding process. However, However, this this requires requires relativelycomplex relatively complex tooling.Preferably, tooling. Preferably, therefore, the therefore, the body body includes includes a a cap retained by cap retained by aa main mainbody bodyportion, portion,the the cap capbeing beingprovided provided with the with the cam surface. The cam surface. Thecap capmay maybe be fittedover fitted overororwithin within the the main mainbody bodyportion. portion.It It may be may be

retained retained byby teeth teeth which which gripgrip the the main main body portion, body portion, ultrasonic ultrasonic welding, welding, a snap a snap fit, a screwfit, a screw

30 30 fit,fit, ororininany anyother otherway. way.

Withthe With theprior priorart artfibre fibreoptic opticcable cable connectors, connectors, it isit necessary is necessary forcollet for the the collet to protrude to protrude

beyond beyond thethe body body to allow to allow an annular an annular gap in gap whichin which the theclip locking locking clip is inserted. is inserted. This is notThis is not

necessary necessary in in thethe present present invention. invention. The collet The collet ring ring can canprotrude still still protrude axially axially beyond the beyond the

35 body, 35 body, but,but, preferably, preferably, in in thethe locked locked position,the position, thecollet collet ring ring does not protrude does not protrude axially axially beyond beyond

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the body. the body.ItItmay maybe be flush flush withwith the the body, body, but isbut is preferably more more preferably recessed recessed into This into the body. the body. This protects thecollet protects the colletring ringfrom from impact impact damage damage and and from from dirt. dirt.

The colletring The collet ringmay maybe be a conventional a conventional annular annular collet collet ring ring that thethat userthe user grips in grips in order to order to

5 5 rotate rotate the the collet colletbetween between the the locking locking and and unlocked positions. However unlocked positions. However anan unlocking unlocking feature feature 2019456730

is is preferably provided preferably provided in in thethe collet collet ring. ring. This This makemake takeform take the theofform of more one or one openings or moreinopenings in the axial end face of the collet ring. However, these require the use of a tool and can become clogged with dirt.

Preferably, therefore, at least one lug projects from the collet ring axially away from the

open end of the through way. This provides a point at which the collet can be readily

gripped for rotation.

The or each lug may not project axially beyond the body. However, the or each lug

preferably projects axially beyond the end of the body. This makes them easier to grip.

Also, these lugs can provide a burr removing function. They can be shaped, for example to

have an abrupt edge, such that a lug can be inserted in to the cut end of a tube and

scraped around the inner edge to remove any burrs left from the tufting process. These can

create snagging hazards, in use, so for an operator to have a tool readily at hand to

remove these will be very useful in practice.

There may be a single lug. However, preferably, there are two or more spaced lugs as this

provides an improved grip and also allows a gripping function to be retained in the event

that one of the lugs is damaged. As stated above, it is preferable that the collet ring does

not protrude axially beyond the body. The or each lug preferably protrudes beyond the axial

end of the body so that it can readily be gripped.

At least one of the body and/or collet is preferably provided with a visual indication of the

locked and/or unlocked positions.

In the vicinity of the locked position, the cam surface is preferably provided with a bump

over which the cam follower rides. This serves to ensure the cam follower remains in the

locked position and also provides a tactile indication to the user that the locked position has

been reached.

When the coupling is used as tube connector, preferably the connector body is made of a

non-opaque plastic.

Further, the body preferably comprises an outer sleeve and in inner sleeve, the inner

sleeve being configured to receive a 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 a gap,

PCT/GB2019/053602

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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 sleeves. This

provides an impact protection feature as the gap allows any impact on the outer sleeve to

deform the outer sleeve which will deform into the gap before it deformed the inner sleeve.

Preferably the connector is devoid of outer ribs and has a continuous outer surface of constant

radius. This eliminates the ribs which are provided on prior art connectors but which provide

stress concentrators and regions in which dirt can accumulate.

Preferably an annular flange extends radially into the through way, each end face of the annular

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

undercut such that its end faces are inclined such that the axial dimension of the flanges

increases towards the axis. This uncut ensures that the inner edge of the tube is able to get

closer to, and preferably abut, the annular flange. This eliminates or minimises the possibility of

a fibre, which is subsequently passed through the connector once the tubes are in place,

becoming snagged on the tube or the annular flange.

Preferably a plurality of annular splines are provided in the vicinity of the annular flange to

deflect deflectthe theouter wall outer of the wall of tube the as it as tube approaches the flange. it approaches theInflange. practice, Intubes are supplied practice, tubes on are supplied on

coils and have often been flattened into an oval cross-section. In the regions where the oval is

at its widest, the inner diameter is larger than it should be and this exposes part of the annular

flange in this region. This provides a snagging hazard for the fibre which is significantly reduced

by the use of the splines.

The invention also extends to a collet for the coupling as defined in claim 17. The collet may

have any of the preferred features defined above.

An example of a 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; wo 2021/005319 WO PCT/GB2019/053602 PCT/GB2019/053602

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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 correspond 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 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

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whether a fibre 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

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

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

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

PCT/GB2019/053602

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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

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 webs 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 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, 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.

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

PCT/GB2019/053602

- 10 10

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.

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 which

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 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 1

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

PCT/GB2019/053602

11

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.

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

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.

PCT/GB2019/053602

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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 in Fig.7E Fig.7B,the thecollet collethas hasnothing nothinglike likethe thesame samedegree degreeof offreedom freedomas asin inFig. Fig.6B 6Bso 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.

The only way to remove the tube T in this locked configuration is for the user to grasp the

tabs 57, rotate the collet 41 in the direction of arrow 61 in Figs. 6A to the unlocked position,

and manually hold the collet in the position shown in Fig 6B while pulling the tube out of the

body 1.

The tube T will usually be inserted with the collet 41 in the unlocked position shown in Figs.

6A and 6B as this allows for more scope for the arms 53 to be deflected upon insertion of

the tube. However, as can be seen in Fig. 7B, even in the locked position, there is a small

clearance between the head 54 and the tapered cam surface 43. Thus, it is possible to

insert the tube T with the collet in the locked position. This provides a simple assembly

process as the user needs only to be told to insert the tube into the collet. They do not

need to concern themselves with the locking operation.

As can be best seen from Figs. 1A to C and Fig. 3, the collet ring 52 is axially set back

inside the body 1. However, the tabs 57 extend beyond the end of the body 1. In this

16 May 2025 2019456730 16 May 2025

position, thecollet position, the collet 41 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

5 5 collet colletring ring52 52and and the thebody body 1. 1. However, theseare However, these areinterfaces interfaces where wheretight tight tolerances can be tolerances can be 2019456730

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. 10 10 Thetabs The tabs57 57have haveright right angled angledcorners. corners.This Thisallows allowsthem themtotobebeinserted insertedinto into the the cut cut end of a end of a

tube TT and tube andscraped scrapedaround aroundthethe inneredge inner edge of of thethe tube tube toto remove remove anyany burrs burrs which which are are

formedduring formed duringthe thecutting cutting operation operation and andwhich whichmight mightotherwise otherwise create create a a snagging snagging hazard hazard

for the for the fibre fibreF.F. The Theedge edge may be shaped may be shapedininaadifferent different way to provide way to provide more moreeffective effective burr burr 15 removal. 15 removal.

Theconnectors The connectors2 2described described above above areare in in thethe combination combination with with an an unconventional unconventional

arrangement arrangement ofofthe theouter outersleeve sleeve5 5and andinner innersleeve sleeve6 6supported supportedby by a web a web 7 and 7 and the the

annular flange 20 annular flange 20 and andthe thesplines splines 30. 30. However However theconnectors the connectors cancan equally equally be be used used in ain a

20 coupling 20 coupling which which has ahas a conventional conventional interior interior without without these these features. features.

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 25 25 may may well well include include other other elements elements not listed. not listed.

Claims (20)

25 Jul 2025 CLAIMS

1. A tube coupling comprising a coupling body having an opened ended throughway to receive a tube, a collet located in the open end of the through way having a ring and a 5 plurality of flexible arms extending generally axially of the ring into the throughway, the 2019456730

throughway having a tapered surface convergent towards the open end and the collet arms having heads at their distal ends for engaging both of the tapered surface and a tube extending, in use, through the collet into the throughway to be compressed against the tube by the tapered surface with outward movement of the collet with respect of the throughway 10 to secure the tube in the throughway; and a collet lock integrally formed on the collet, the collet having a locked rotary position in which the lock holds the collet in an outward tube securing position and an unlocked rotary position in which the collet can move axially with respect to the throughway for release and engagement of a tube by the collet; 15 wherein one of the body and the collet is integrally formed with a cam surface and the other of the body and the collet is integrally formed with a cam follower, the cam surface being provided to provide the locked and unlocked positions.

2. A coupling according to claim 1, wherein the cam surface is on the body. 20

3. A coupling according to claim 2, wherein the body includes a cap retained by a main body portion, the cap being provided with the cam surface.

4. A coupling according to any preceding claim, wherein the collet ring does not 25 protrude axially beyond the body.

5. A coupling according to claim 4, wherein the collet ring is recessed into the body.

6. A coupling according to any preceding claim wherein an unlocking feature is 30 provided on the collet ring.

7. A coupling according to claim 6, wherein at least one lug projects from the collet ring axially away from the open end of the throughway.

WO wo 2021/005319 PCT/GB2019/053602

15

8. A coupling according to claim 7, wherein the or each lug project axially beyond the

body.

9. A coupling according to claim 8, wherein the or each lug has an abrupt edge.

10. A coupling according to any preceding claim wherein at least one of the body and/or

collet is provided with a visual indication of the locked and/or unlocked positions.

11. A coupling according to any preceding claim, wherein in the vicinity of the locked

position, the cam surface is preferably provided with a bump over which the cam follower

rides.

12. A coupling according to any preceding claim, wherein the connector body is made

of a non-opaque plastic.

13. A coupling according to any preceding claim, wherein the body comprises an outer

sleeve and in inner sleeve, the inner sleeve being configured to receive a 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 a 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 sleeves.

14. A coupling according to any preceding claim, wherein the connector is devoid of

outer ribs and has a continuous outer surface of constant radius.

15. A coupling according to any preceding claim wherein an annular flange extends

radially into the through way, each end face of the annular flange providing a stop surface

for a respective tube end, wherein the annular flange is undercut such that its end faces

are inclined such that the axial dimension of the flanges increases towards the axis.

16. A coupling according to claim 15, wherein a plurality of annular splines are provided

on the wall of the through bore in the vicinity of the annular flange to deflect the outer wall

of the tube as it approaches the flange.

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17. 17. A collet A collet forfor a a tube tube coupling coupling according according to to any any oneone of of thethe preceding preceding claims, claims, thethe collet collet

comprising a ring comprising a ring andand a plurality a plurality of flexible of flexible armsarms extending extending generally generally axially axially of of the the ring, thering, the

flexible arms flexible having arms having heads heads at their at their distal distal end awith end with a on tooth tooth on a radially a radially innermost innermost face for face for gripping gripping aatube, tube,ininuse, use, thethe heads heads extending extending radially radially outwardly outwardly of the flexible of the flexible arms in an arms in an

5 5 opposite direction opposite direction from from the the teeth teeth onradially on the the radially innermost innermost face; face; 2019456730

the collet the collet being beingprovided provided with with a collet a collet locklock feature feature in form in the the form of afeature, of a cam cam feature, the the cam featurebeing cam feature beingarranged arrangedsuch such thata adepth that depth toto which which the the colletcan collet canbebeinserted insertedinto into aa coupling body, coupling body, in in use, use, will will differwith differ with different different angular angular positions positions ofcollet, of the the collet, whereinthethe wherein camcam feature feature is a is camafollower cam follower extending extending frominthe from the ring thering in theofdirection direction of 10 10 thethe flexible arms. flexible arms.

18. 18. A collet A collet according according to claim to claim 17,17, wherein wherein an unlocking an unlocking feature feature is provided is provided on the on the collet collet

ring. ring.

15 15 19.

19. A collet A collet according according to claim to claim 18,18, wherein wherein the the unlocking unlocking feature feature is provided is provided by by at at least least

one lugprojecting one lug projecting from from the the collet collet ringring axially axially in the in the direction direction opposite opposite to the to the direction direction in in which the which the arms armsextend. extend.

20 20 20.

20. A according A collet collet according to 19, to claim claim 19, wherein wherein the or the eachorlug each haslug an has an edge. abrupt abrupt edge.