IE922837A1 - A joint enclosure - Google Patents

Abstract

A joint enclosure .(1) is disclosed for telecommunications X cables (3) which are pressurised. An end cap (5) is screwed onto a cylindrical portion (3) and a plug is inserted within the cylindrical portion (3). The end cap (5) has projections (17) with engagement surfaces (18) for engagement with engagement surfaces (30) of a wrap-around portion of a torque wrench. This allows the end cap (5) to be secured to the cylindrical portion (3) and the plug (77 with a desired torque, irrespective of pressure applied or temperature cycling on the joint enclosure (1).

Description

The invention relates to a joint enclosure for telecommunications or other cables which are pressurised.

An enclosure of this type is described in British Patent Specification No. 2177550. The enclosure comprises a cylindrical enclosure body, a plug forming an insert in the body and an annular end cap which completes an hermetic between the body and the plug. Creation of a satisfactory seal is indicated by rotation of the end cap until markings on the end cap and the cylindrical body are in alignment, which indicates that there is a sufficiently high torque. Such a joint enclosure is satisfactory in many situations. However, under conditions of temperature and/or pressure cycling of a relatively wide range, a certain amount of creep occurs in the enclosure (which is of plastics moulded construction). When this happens, the extent to which the end cap must be rotated in order to generate the correct torque varies and the markings on the end cap and cylindrical body are no longer appropriate. This can lead to the enclosure not being hermetically sealed, resulting in considerable inconvenience and time in locating and repairing faults.

The invention is directed towards providing a joint enclosure to overcome these problems.

JNL. No.....

Statements of Invention According to the invention there is provided a joint enclosure comprising an enclosure body and a removable end cap having screw threads for interengagement, wherein the end cap has a formation with a radially directed surface for engagement with a surface of a corresponding formation of a wrap-around portion of a torque wrench.

In one embodiment, the formation on the end cap is a projection.

Preferably, the formation extends in a longitudinal direction.

In one embodiment, there is at least one pair of diametrically opposed formations.

In another embodiment, the end cap is of annular shape 15 having inner and outer threads for engagement with the threads of a plug and of the body, respectively, and wherein the joint enclosure further comprises a gasket and an outer end of the end cap to prevent pinching of the gasket. - 3 The invention will be more clearly understood from the following description of some preferred embodiments thereof, given by way of example only with reference to the accompanying drawings on which:5 Fig. 1 is a perspective view of a joint enclosure of the invention; Fig. 2 is a detailed cross-sectional view of portion of the joint enclosure; Fig. 3 is a perspective view from above of a torque wrench for use with the enclosure; Figs. 4 and 5 are perspective views showing different stages of a application of an end cap to the enclosure and; Fig. 6 is a diagrammatic end view showing the manner in which the end cap is secured in position.

Referring to the drawings, and initially to Figs. 1 and 2 a joint enclosure 1 of the invention is shown. The joint enclosure 1 comprises an enclosure body 2 having a cylindrical portion 3 and a domed end 4. The enclosure 1 also includes an annular-shaped end cap 5, through which cables 6 pass for connection on circuits mounted on a plug insert 7 within the enclosure body 2.

The joint enclosure 1 may be used for housing joints in telecommunications cables such as optic cables. For such an application it is extremely important that the enclosure provide an hermetic seal under difficult conditions of both temperature and pressure cycling.

»E 922837 - 4 Referring specifically to Fig. 2, it will be seen that the end cap 5 has a set of outer threads 8a, and a set of inner threads 8b. The outer threads 8a are for engagement with threads 9 on the enclosure body 2, while the inner threads 8b are for engagement with threads 10 on the plug insert 7. As shown in Fig. 2, the end cap 5 seals the plug insert 7 and the enclosure body 2 together by sandwiching them between the threads 8a and 8b. A rubber gasket 15, behind which there is a lubricated slip ring 16 help to ensure that a very effective hermetic seal is created on application of the end cap 7.

To help ensure that integrity of the seal is maintained during difficult conditions such as during pressure and temperature cycling, the end cap 5 includes a set of longitudinally-directed projections 17 having radiallyextending engagement surfaces 18. The enclosure body 2 has longitudinally-directed projections 19 with radiallydirected engagement surfaces 20.

Referring now to Fig. 3, there is illustrated a torque wrench for use in application of the end cap 5 to the enclosure body 2 to help ensure that integrity of the seal is maintained during use. The torque wrench 24 has a wrap-around portion 25 for surrounding the end cap 5. This has a pair of semi-circular halves 26 connected by a hinge 27 at one end and releasably connected by a fastener 28 at the other end. The halves 26 have inwardly-directed rectangular projections 29 at diametrically opposed positions. The projections 29 have inwardly and radiallydirected engagement surfaces 30. The torque wrench 24 also comprises a handle 31 with an indicating gauge 32. The handle 31 has a bar 34 for engagement with the sleeves 33 on each of the halves 26 of the wrap-around portion 25.

In use, telecommunication cables are connected through - 5 apertures in the plug 7 and then the ends of the cable are connected on circuits on mounted on the plug 7. To seal the joint enclosure 1, the end cap 5 (through which the cables have been run) is offered up to the end of the enclosure body 2 and is rotated by hand so that the various threads inter-engage. As shown in Fig. 2, the end cap threads 8a and 8b engage the threads 9 and 10, respectively. Thus, the end cap 5 acts to sandwich the plug and the enclosure body together. The end cap 5 is then rotated until the torque requirement becomes too high for this to be continued manually. At this stage, a wraparound grip such as that indicated by the numeral 36 in Fig. 5 is placed around the cylindrical portion 3 of the enclosure body 2 at the projections 19. The grip 36 engages the projections 19 at the engagement surfaces 20. The wrap-around portion 25 of the torque wrench 24 is then placed around the end cap 5 and the fastener 28 is used to fasten it in place. While this is being done, care is taken to ensure that the engagement surfaces 30 of the projections 29 engage with the engagement surfaces 18 of the projections 17. This is illustrated most clearly in Fig. 6. In general, if the engagement surfaces are not abutting when the wrap-around portion 25 has been put in position, they will engage when the torque wrench is used.

When this has been done, the handle 31 is placed on the wrap-around portion 25 by engagement of the bar 34 with the sleeve 33 which is in the most convenient position, generally on the upper side of the joint enclosure 1. The wrap-around grip 36 and the handle 31 are then pushed in opposite directions as shown in Figs. 5 and 6 to further rotate the end cap 5 onto the enclosure body 2. This operation is continued until the correct torque reading is displayed on the indicator 32. Accordingly, the end cap 5 generates a seal between the plug 7 and the enclosure body 2 which maintains its integrity, even during - 6 temperature or pressure cycling. The rubber gasket 15 and the slip ring 16 also help to ensure that an effective seal is maintained. The slip ring 16 helps to ensure that the gasket 15 is not pinched or damaged by friction.

It would be appreciated that the invention provides for the prevention of sealing problems during difficult ambient conditions in a simple manner. This is extremely important because the joint enclosure would often be installed under difficult conditions underground where access is difficult and it is thus important that sealing of the enclosure is kept as simple as possible. It is envisaged that the torque wrench may be relatively simple so that it provides only a single torque indication suitable for the joint enclosure.

It is envisaged that instead of projections on the end cap and enclosure bodies, there may be indentations which have engagement surfaces. The important point is that there are radially-directed surfaces for engagement between the torque wrench or grip and the enclosure body or end cap.

The number of formations may be chosen for convenience so that there is a suitable diametrically opposed pair of formations for several different positions of the torque wrench.

The invention is not limited to the embodiments herein before described, but may be very different in construction and detail

Claims (6)

1. A joint enclosure comprising an enclosure body and a removable end cap having screw threads for interengagement, wherein the end cap has a formation with a 5 radially directed surface for engagement with a surface of a corresponding formation of a wrap-around portion of a torque wrench.

2. A joint enclosure as claimed in claim 1, wherein the formation on the end cap is a projection. 10

3. A joint enclosure as claimed in claims 1 or 2, wherein the formation extends in a longitudinal direction.

4. A joint enclosure as claimed in any preceding claim, wherein there is at least one pair of diametrically opposed formations. 15

5. A joint enclosure as claimed in any preceding claim, wherein the end cap is of annular shape having inner and outer threads for engagement with the threads of a plug and of the body, respectively, and wherein the joint enclosure further comprises a gasket within the 20 end cap and a slip ring mounted between the gasket and an outer end of the end cap to prevent pinching of the gasket.

6. A joint enclosure substantially as hereinbefore described with reference to and as illustrated in 25 Figs. 1, 2, 4, 5 and 6 of the accompanying drawings.