GB2088147A - Device for reopening an installed cable joint - Google Patents

Abstract

A device for reopening installed cable joints in a sheath jacket 3 comprises a separating thread 5 extending along the joined cables 1,2. After the sheath 3 has been heated along the vicinity of thread 5, its free end 6 is pulled to rip open the sheath 3 to expose the cable connection. The sheath may consist of two interengaging parts each with two cables leading to and from an internal electronic connector. A different separating thread may be provided along each cable for ripping the associated sheath part in half. The thread is preferably steel and may have a lenticular cross-section with sharp edges extending along the sheath equidistantly from its inner surface in which the thread may be embedded in an adhesive layer on that surface. <IMAGE>

Description

SPECIFICATION Device for reopening an installed cable joint The present invention relates to a device for reopening an installed or finished cable joint with sheath jacket or parts of heat-shrinkable material surrounding an inner cable connection, the device being particularly suited to cable for signal and wide-band communications.

Reopening such installed cable joints including sheath parts of heat-shrinkable material has created great difficulties up to now. For example, with cable joints including a longitudinally slit sheath jacket of heat-shrinkable material, the edges of the slit are connected with one another by means of an elongated connecting member having a C-shaped transverse cross-section.

Therefore, detaching of the connecting members after shrinking-on the sheath parts is practically impossible due to large forces exerted on the connecting member as a result of the shrinkage.

Therefore, when reopening the known cable joint, one must first carefully pierce the jacket of heat-shrinkable material and, if present, an inner protective insert on top and on the bottom in the transition area toward the cable ends. This procedure is carried out, if necessary, after prior puncturing by heating. Next, the joint ends must be preheated, and then the entire area of the connecting member is intensely heated whereupon the area of the sheath in the region of the slit edges is cut away along with the connecting member which surrounds the edges.

Further, beginning at the area of overlap, the entire jacket must be heated again and then pulled off from the joint in the longitudinal direction (Assembly Instructions VASM, Rose Fernmeldetechnik Company (Signal Communications Technology), effective August, 1980, page 12).

Aside from the fact that this opening procedure is very time-consuming, since one must proceed with great care, it can still easily happen that during the various required cutting steps, damage to the cable ends or cable splices located on the inside of the cable joint can occur. This is something that absolutely must be avoided, particularly in highly sensitive wide-band communication cables.

An object of the invention is to provide a device such that damage to cable connection parts located inside the cable joint is substantially impossible notwithstanding a quick and simple opening procedure for the joint.

In accordance with the present invention, a device for reopening installed or finished cable joints includes a sheath jacket or parts of heatshrinkable material surrounding an inner cable connection between cables entering the sheath jacket or parts along predesigned paths, the jacket or at least one sheath part including a wall having an inner surface surrounding the cable connection, and a separating thread being arranged in the wall adjacent the inner surface and extending from one end to the other end of the said sheath jacket or part in the direction of the cables for opening the wall of the said sheath jacket or part in response to a pull applied to said thread.Because of this construction, reopening of an installed cable joint is simply carried out by first moderately heating the sheath jacket or part to be opened in the region of the separating thread, and ripping open the sheath jacket or part by pulling the thread thereby allowing the interior of the cable joint to be easily accessed.

In sheath parts having several cable entrances at one end, it is particularly advantageous to provide a different separating thread for each cable entrance. For expediency, two separating threads can be arranged parallel to one another on opposite sides of a sheath part, so that when both separating threads are pulled, the sheath part ripped open (e.g. a sheath jacket) falls apart into two halves which then can be easily removed.

In order that the temperatures developed during preheating can be withstood it is preferable to make the separating thread in the form of a thin wire, particularly a steel wire.

Penetration or digging-in of the separating thread into the casings of the cable ends leading into the cable joint can be prevented by imparting a flattened, lens-shaped cross-section to the separating thread, the opposite longitudinal edges of the thread being sharply pointed. Accordingly, the separating thread occupies as little area in the radial direction of the joint as is possible, and yet it can slice through the sheath part with one of the sharply pointed edges when the sheath part is to be opened.

The opening procedure can be facilitated further by providing a handle at least at one end of the thread, which end protrudes slightly beyond the corresponding sheath part. The handle may be in the form of a bulge, a loop or the like.

The separating thread also may be embedded in an adhesive layer applied to the inside of the sheath part, so that the thread is correctly positioned during handling and, moreover, a good seal results in the cable entry regions of the sheath part.

Alternatively, the separating thread may be embedded into and made flush with the inner surface of the sheath part, extending, for example, in longitudinally formed recesses over the entire cable joint and being of essentially uniform strength.

The various features of novelty which characterise the invention are pointed out with particularity in the claims annexed to this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

In the drawings: Figure 1 is a perspective view of a cable joint with a single-piece sheath jacket; Figure 2 is a perspective view of a cable joint having two moulded sheath parts, one providing a socket for the other; Figure 3 is a sectional view through a sheath part showing a separating thread embedded in an inner adhesive layer; and Figure 4 is a sectional view through a wall of a sheath part showing a separating thread embedded in the wall.

In Figure 1, two cables 1 and 2 lead into a cable joint formed by an elongated sheath jacket 3 of heat-shrinkable plastics material, the jacket 3 having a longitudinal slit (not shown). The slit edges of the sheath jacket are held together by an elongated connecting member 4 having a C-shaped transverse cross-section and transverse slits. A cable splice located inside the sheath jacket is surrounded by a protective sheathing (not shown) onto which the sheath jacket 3 is heat shrunk. The sheath jacket 3 is initially provided with a separating thread 5 which extends longitudinally and on the side opposite to the edges of the sheath jacket which are joined by the connecting member 4. During heat shrinking, the separating thread follows the contour of the sheath jacket.

If reopening of the installed or finished cable joint is necessary, then only a longitudinal strip of the sheath jacket 3 adjacent the separating thread 5 must be heated. Then, the separating thread 5 is grasped at a bulge 6 at one end of the thread and pulled. The sheathing thus is ripped open without any possibility of damage to the cable connection parts located inside of the cable joint.

In the embodiment shown in Figure 2, a cable joint or connection is formed of an inner moulded sheath part 7 and an outer moulded sheath part 8 which provides a socket for the part 7. The inner moulded part 7 has two sleeve-like cable entrance portions 9 and 10 and the outer moulded part 8 also has two sleeve-like cable entrance portions 1 1 and 12, through which entrance portions wideband communications cables 13, 14, 15 and 16 are led. The cables terminate in an electronic connector (not shown) located inside of the connected moulded sheath parts.

The inner moulded parts 7 is equipped with two separating threads 17 extending in the direction of the cable and on opposite sides of the inner moulded part, from each of the cable entrance portions 9, 10 to the end of the inner moulded part 7 within the outer moulded part 8. The separating threads 17 project slightly from the cable entrance portions, and are each provided with a bulge 18 at their free ends. In the same manner, the outer moulded sheath part 8 is provided with an additional set of two separating threads 1 7.

When reopening the cable joint of Figure 2 becomes necessary, only longitudinal strips of the two moulded sheath parts 7 and 8, situated adjacent the separating threads 17, need be heated in order that the moulded sheath parts can be ripped or torn open by the separating threads 17. This results in an especially favourable opening arrangement wherein the moulded parts are separated into two equal halves, and makes possible the removal of the moulded parts from the inner cable connection in an especially simple manner, that is, without any possibility of damage to the inner cable connection parts.

The separating threads 17 preferably are formed as thin, string-like steel wires, in order to withstand temperatures developed during heating of the sheath parts to be opened. Of course, plastic threads may also be used should these be available with sufficient strength and heatresistance.

In the embodiment shown in Figure 3, a separating thread 19 of lens-shaped cross-section is embedded in an adhesive layer 21 applied to the inner wall of a sheath part 20, in such a way that the separating thread 19 occupies very little space in the radial direction. Moreover, the danger of damage to casings of cable ends leading into the sheath parts caused by the digging-in of the thread is eliminated as much as possible.

Embedding the separating thread 19 into the adhesive layer 21 allows, on the one hand, a desirable orientation of the thread during handling of the sheath part 20 and, on the other hand, a good seal at the end regions of the sheath part, particularly at the ends of tapered cable entrance portions.

In the embodiment shown in Figure 4, a separating thread 22 of lens-shaped cross-section is embedded into a sheath part 24 in alignment or flush with the surface of the inner wall 23 of the sheath part 24. At the inside, there is once again applied an adhesive layer 25 against the sheath part. Any danger of damage to incoming cables by the separating thread digging into the cable casings is practically entirely ruled out with this arrangement. Moreover, separation is facilitated in that cutting edges 26 on both sides of the separating thread 22 are already located in the material of the sheath parts 24, that is, the edges no longer must penetrate into the material when the sheath part is to be ripped open.Accordingly, the thread can be pulled out of the sheath part 24 with relative ease along a cutting line 27, indicated by a broken line in Figure 4, and with complete separation of the sheath part 24.

Of course, the embodiments described above can be altered in many ways without departing from the fundamental concept of the invention.

For example, the moulded sheath parts 7. 8 of Figure 2 may be provided with a separating thread running through in the longitudinal direction over the full length of the moulded parts as well as one cable entrance portion, and additional separating threads may run only through the remaining cable entrance portions up to the cable entrance portion associated with the through running separating thread. The material and shape of the separating threads can be varied in many ways to obtain a better cutting effect and reduction of the preheating of the sheath parts in the region of the separating thread. This is especially significant in very sensitive, wide-band communications cables.

The band grip provided by the bulge 6, 18 may be replaced by a loop.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the invention principles, it will be understood that the principles of the invention may be embodied otherwise without departing from the scope of the following

Claims (14)

claims. CLAIMS

1. A device for reopening installed or finished cable joints including a sheath jacket or parts of heat-shrinkable material surrounding an inner cable connection between cables entering the sheath jacket or parts along predesigned paths, the jacket or at least one sheath part including a wall having an inner surface surrounding the cable connection, and a separating thread being arranged in the wall adjacent the inner surface and extending from one end to the other end of the said jacket or sheath part in the direction of the cables for opening the wall of the said jacket or sheath part in response to a pull applied to said thread.

2. A device according to claim 1, comprising sheath parts of which at least one includes a wall having an inner surface surrounding the cable connection and includes at least two cable entrance portions, and a different separating thread associated with each of said cable entrance portions.

3. A device according to claim 1 or claim 2, wherein said separating thread or each separating thread is formed of a relatively thin wire.

4. A device according to claim 3, wherein said thin wire is a steel wire.

5. A device according to claim 1, wherein said separating thread has a relatively flat, lens-shaped transverse cross-section forming two sharply pointed edges extending longitudinally and on opposite sides of said thread.

6. A device according to claim 1, wherein a free end of said separating thread projects slightly beyond at least one end of said sheath jacket or part, said thread including a hand grasp at said free end.

7. A device according to claim 6, wherein said separating thread is enlarged at said free end to form said hand grasp.

8. A device according to claim 6, wherein said separating thread is looped at said free end to form said hand grasp.

9. A device according to claim 1, comprising sheath parts of which at least one includes a wall having an inner surface surrounding the cable connection, an adhesive layer being applied to said inner surface, and said separating thread being embedded in said adhesive layer.

10. A device according to claim 1, comprising sheath parts of which at least one includes a wall having an inner surface surrounding the cable connection, said separating thread being embedded into and flush with the inner surface of said wall.

11. A device substantially as hereinbefore described with reference to Figure 1 of the accompanying drawings.

12. A device substantially as hereinbefore described with reference to Figure 2 of the accompanying drawings.

13. A device substantially as hereinbefore described with reference to Figure 3 of the accompanying drawings.

14. A device substantially as hereinbefore described with reference to Figure 4 of the accompanying drawings.