CA1302691C - Sealed jointing apparatus - Google Patents

Abstract

Abstract of the Disclosure Sealed jointing apparatus for use in the connection of conduit sections comprises an annular casing having open ends, spaced end closures at the ends of the casing and defining with the casing a connection zone into which conduit sections pass for jointing. Releasable securing means are provided for releasably securing at least one of the end closures to the casing. The releasable securing means comprise an end cap which has an aperture and includes two radially spaced coupling threads, one of which coupling threads threadingly engages an external thread on the casing while the other coupling thread engages an internal thread on at least one end closure whereby the casing is releasably coupled to at least one end closure. Alignment means are provided for annular alignment of the internal and external threads and comprise tooth means on one of the casings and one end closure and a groove on the other of the casing or said one end closure to receive the tooth means.

Description

~30Z69~

SEALED JOINTING APPARATUS
This invention relates to sealed jointing apparatus for use in the connection of conduit sections at a connection zone, and more specifically, but not necessarily, relates to a flexible hermetically sealed cable splice/jointing point.
The present invention will find particular use in the telecommunications and electric industrial fields.
However, it can also be used in gas or water pipe systems to enable greater flexibility in these systems.
Up until now, in telecommunication cable work with different types of cables, such as coaxial, fibre optical and multi core, all types of cable closure method used the outside of the cable sheath for affixing the seal.
Therefore, the outer sheath of any cable had to enter into the area which would contain the conductor splices.
It has been well recognized within the electrical and telecommunication fields that this type of splice closure method often failed at the point of seal between the cable sheath and the main splice/joint sleeve (referred to as the primary seal means) with the result that moisture could penetrate the joint thereby causing the failure of the contained circuits. In order to overcome these deficiencies, the industries have used additional method steps which include (1) air pressurization of the system and (11) splice/joint encapsulation using resins or jelly substances and oil filling of the splice area. These methods had the disadvantage of being expensive and labour intensive and in most cases the flexibility of the system was greatly impaired.
Also in this type of splice, the cables' aluminium screen had to be jumped across the splice by affixing a continuity wire to the butts of all cables contained within.
To enter previous straight through joints, cable seals have always had to be broken which again is expensive and time-consuming and depending on the size and type of cable very possibly a two-man operation.
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~302691 It is an object of the present invention to obviate or mitigate these disadvantages and to provide a jointing point which can be both quickly entered and closed.
5According to the present invention there is provided sealed jointing apparatus for use in the connection of conduit sections comprising an annular casing having open ends; spaced end closures at the end of the casing, and defining with the casing a connection zone into 10which conduit sections pass for jointing; and releasable securing means for releasably securing at least one of the end closures to the casing; said releasable securing means comprising an end cap including two radially spaced coupling threads, one of which coupling thread threadingly 15engages an external thread on the casing while the other coupling thread engages an internal thread on said one end closure whereby the casing is releasably coupled to said one end closure, and alignment means for annular alignment of said internal and external threads comprising tooth 20means on one of said casing and said one end closure and a g-oove on the other of said casing or said one end closure to receive the tooth means.
By means of the present invention, the conductor splices in joined telecommunication cable sections can be 25contained in a hermetically sealed zone bounded by the end closures and the casing, and access can be had to the cable splices simply by releasing the releasable securing means and pushing the casing aside: the end closure means remain in position and the primary seal means which are provided 30at the end closure are untouched. Closure of the joint simply comprises the reverse of this operation. It will be understood that such access without breaking the cable seal (ie the primary seal) provides considerable operational and economic advantages.
35Openings for the conduit sections will be provided in at least one end closure and primary seal means are 130~69~
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_ 3 _ preferably provided at said opelnlngs. The primary seal means rnay involve injection weldi`ng aroun`d the conduit section nt l~he opening or may comprise a sealing collar filter by heat shrinking.
Preferably, a pair of annular members are provided and spacer mean4 serve to axially spsce the annular members by a predetermined a~ount.
An Embodiment of the present invention will no~ be de-scribed by ~ay of example, with reference to the accompanying drawings, in which:- -Flg. 1 shows a side view of a fl~xible hermeticallysealed cable splice/jointing apparstus or joint, part of one end of which is shown sectione~;
Fig. 2 sho~s an isometic "exploded" view of one end of the ~oint of Fi8. 1;
Referrin8 to the drawings, ~ointing apparatus 1 serving as a ~olnting polnt forthe spllcing of a pair of opposed telecommunication cable sectiohs 2A, 2B (the apparstus 1 . permits the ~ointing of a plurality of cable section pairs) comprises a cylindrical casing 17 ciosed at the ends by si~ilar end plugs 3. The apparatus 1 i9 symmetrical about mid-tr~nsverse median plane, and the cssing 17and the end plugs 3 define a closed chamblr con~tituting a connection or jointing zone for the cable se.ctions 2A, 2B. Referring speclfically to Fig. 1, each end plug comprises a peripheral wall S and a radial base 4, an outer cylindrical surface. of the wall 5 bearin8 against an inner cyclindrical wall portion at the respective end of the casing 17, and one or more re-ceiving tubes 6 (four shown), of nose-form extend axi~lly from each end plug 3, the tubes 6 on the right side end plug 3 being complementary to those on the left side. The tubes 6 serve to guide the conduit sections 2A, 2B into the casing 17 for ~oining, and as can be seen in Fig. 1 the outer ends of the tubes 6 are initiallyiof blind for~ so that the tubes 6 can be selectively used bylopening the outer blind ends of ' 1~i0269~ `
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appropriate tu,bes 6. Each end plug 3 is sealingly joined to the res~ctive end~~f th~ c~sing 17 by an ,Annulsr end C8p 19 as will now be explained in detail.
Each end of the cssing 17 carries an external thread 18 whllo tho w~ll 5 of oclch pl~; 3 carrlc~ c~n intel-nc~l Lh~
7. The annular end cap 1,9,carriec a pair of opposed thread-ings 20,'21 o-n'axial ~alls l9A, l9B which can en~age wi~h the threads 18 and 7 respectively so that the cap 19 can be screwed onto the threads 7, 18 to secure the cssing 17 to the end plug 3. To facilitate the fitting of the cap 19 on the threads 18, 7, means are proYided for the annulsr slignment of the threads 18, 7, these alignment means specifically being in the form of a rib 40 on the internal wall of the casing 17 and a groove 41 (see ~ig. 2) on each end plug 3 shaped to receive the rib 40. Conveniently the rib 40 extends axially from end to-end in the casing 17. Further, to convenience assembly of the joint 1 and also the splicing operations of the sections 2A, 2B, the end plugs 3 are preerably connected to each other at a precise axial spacing by means of ~pscing means:or the present embodiment, these spacing mean~ can take the form of a central tube 42 which is located on central boss portions 43 on the end plugs 3 -this central arrangement'enables an uninterfered sccess to the sections 2A, 2B at the splicing zone (wlth, of course, the casing 17 moved aside for access). Screen continuity for the telecommunication cable can be provided acro~s the ~oint by any suitable means. The end cap 3 and ca~ing 17 are of a plastics material having a U-V stabiliser such as càrbon black as may the end plu~. The cap 19 can be knurled (as shown) to facilitate tightenin~. A primary seal means will be provided between the tubes 6 and the respective cable s~e~tions 2A, 2B to preven~ ingress of moisture to the in-terior of the apparatus'l and th~s seal mean,s can be in different forms depend~ng'on the use of the ~oint. Thus the primary seal means canibe either a heat shrinkable collar or a jointing compound injec!tion welded between the tube 6 snd the associated cable be,ct~on. A hand ~ointi,ng tool to i' ~302691 facilitate the splicaing operàtion o~ the cable sections can be provided in the casing 17.
The jointing (splicing) operation is carried out as follows:-Prior to preparation of the cable sections 2A, 2B the appropriate parts are placed over the respective cable section and in the following sequence: end cap 19 and then end plug 3. The casing 17 can be placed oYer any one of the two sections 2. The following description relates generally to the operation at one end of the Joint; the operation at the other end is similar. The cable end is now prèpared for splicing by removing a length of the cable outer sheath taking care not to disrupt tbe cable core formation as this will make the placing of the end plug difficult and could cause damage to the insulation of the conductors contained in the cable. The cable sections 2A, 2B are inserted through the appropriate tubes 6 which will have their outer ends opened.
The spacer tube 42 is placed in position ~oining both end plug~ 3. As will be noted, the axial length of the tube 42 i8 significant since it controls the marriage of the end plug 3 to the main sleeve or casing 17 by means of the double threaded end cap 19.
The conductor pairs of the cable sections 2A, 2B are now ready for splicing, and splicing is facilitated by the hand tool so leaving the hands free for the splicing oper-ation. Appropriate stepsc~nbe taken to ensure screen con-tinuity across the joint. When splic~ng has been completed, the casing 17 is positioned between the end plug 3 and sec-ured by the end caps 19 which are screwed onto the casing17 and into the end plug 3 in the same operation. Final ti8htening of the end cap 19 should be done using two strap w~enches, one to hold the casing 17 and the other to ti8hten the end C8p 19. The rib 40 and grooves 41 prevent relative movement between casing 1/ and the end plugs 3 during the ti8htening operatlon.

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~ 6 -To re-enter the ~oint at any time only the end c~ps 19 need be unscrewed to enable the casing 17 to be pushed aside; the primary seal means and screen continuity will re-- main in position untouched. The above splice joint provides the additional signiEicant advantage of the sheath not having to be brought into the splicing area. By this ar-rangement the possibility of splice failure due to ingress oE moisture i8 virtually ruled out. ModiicAtions are of course possible. Thus, for example, only one end of the ~oint may confor~ to the arrangement shown in Fig. 1. Also the casing may only have a single entry i.e. the other end may be blind.
By the provision of the plurality of tubes 6, the ~ointing of two or more c~bles is possible in the single jointing apparatus 1. The bore~ 6 can be initially blind and are subsequently cut to provide through bores only when required for use. A 8reater or less number of tubes 6 could be present, eg only a single entry may be used, preferably utilising different spacer means. The above example des-cribes apparatus suitable for thé splice ~oint for a tele-communication cable, and is also applicable for the ~oin of anelectricalcable. Further the spparatus could be readily adapted for the connection of conduits in gas and water pipe systems.
As an alterna~ive for the thread alig~ent means, it would be possible to have the rib (or tooth) on the end plug 3 and the receiving groove in the casing 17. Means can be provided to hold the cap 19 in position against unauthorised entry.

Claims (8)

1. Sealed jointing apparatus for use in the connection of conduit sections comprising an annular casing having open ends; spaced end closures at the ends of the casing, and de-fining with the casing a connection zone into which conduit sections pass for jointing; and releasable securing means for releasably securing at least one of the end closures to the casing; said releasable securing means comprising an end cap having an aperture and including two radially spaced coupling threads, one of which coupling threads threadingly engages an external thread on the casing while the other coupling thread engages an internal thread on said at least one end closure whereby the casing is releasably coupled to said at least one end closure and alignment means for an-nular alignment of said internal and external threads comp-rising tooth means on one of said casing and said one end closure and a groove on the other of said casing or said one end closure to receive the tooth means.

2. Apparatus as claimed in claim 1, wherein the end closures comprise annular members.

3. Apparatus as claimed in claim 1, wherein the tooth means comprises an axial rib on the internal wall of the casing, the said one end closure including an axial groove to receive said rib.

4. Apparatus as claimed in claim 3, wherein the axial rib extends from end to end in the casing.

5. Apparatus as claimed in claim 1, wherein spacer means extend between the end closures and serve to axially space the end closures by a predetermined amount.

6. Apparatus as claimed in claim 5, wherein the spacer means comprises a central tube.

7. Apparatus as claimed in claim 1, wherein said one end closure includes an array of axially extending guide channels for the conduit sections.

8. Apparatus as claimed in claim 7, wherein each guide channel is defined by one elongate nose-form tube.