Note: Descriptions are shown in the official language in which they were submitted.
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CLOSURE FOR TELECOMMUNICATIONS CABLE
This invention relates to closures for telecom-
munications cables.
In the telecommunications industry, cable lengths
need to be spliced together either to provide a sufficiently
long length of cable run between two points or to splice a
branch cable into a main cable. In the telecommunications
cable field, splices are provided both in greased filled and
air pressurized cable. Splices are enshrouded by a closure
to prevent degradation of the splices and of the conductors
and cable in the immediate region at each side of the splice.
In some telecommunications splice closures, encapsulant
directly surrounds the splices and cable and a housing
surrounds the encapsulant. In other closures, e.g. for
connecting together optical fiber conductors of an optical
cable, it is not desirable for encapsulant to contact the
fibers or splice regions directly. In such closures, a dual
closure structure may be used in which separate inner and
outer closure housings are provided with moisture blocking
encapsulant disposed between them. The inner closure
surrounds, but is spaced from, the splices and conductors in
the splice regions.
The present invention seeks to provide a simplified
closure structure which in use provides the same sealing
advantages as the conventional dual closure structure.
According to the present invention, a closure
structure is provided for a telecommunications cable splice
comprising two housing parts which are sealingly connectable
together, the housing parts having wall means which, when the
parts are connected together, provide a splice chamber within
the structure and a space around the splice chamber which is
separated from the chamber by the wall means, the space
disposed between closing together regions of the housing
parts for containing a moisture blocking material and the
housing parts defining recesses which coact in the assembly
to provide cable entrance openings into the chamber.
More particularly the present invention provides a
closure structure for a telecommunications cable splice
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comprising two housing parts each having an inner wall means
surrounding an opening at one side of the housing part and an
outer wall means spaced outwardly from the inner wall means
and away from the opening, the housing parts being securely
"'connectable one to the other to close the openings and
surround a splice chamber, the housing parts defining
recesses which coact in the assembly to provide cable
entrance openings into the chamber and, in the assembled
condition of the housing parts, the inner wall means seal
against one another to define a boundary for the splice
chamber and the outer wall means seal against one another to
define spaces between the inner and outer wall means for
containing moisture blocking material.
With the structures according to the invention, the
space that is provided between the housing parts may merely
be sufficient to lie between the sealed together inner wall
means and the sealed together outer wall means of the housing
parts so that when moisture blocking material is disposed
within this space it prevents the ingress of moisture from
the surrounding environment. As can be seen, the water
blocking material is thus localized in the region immediately
adjacent to the sealed inner and outer wall means instead of
extending completely around an inner housing as in conven-
tional arrangements. Further to this, the present invention
avoids the use of two complete housings, i.e. one inside the
other, in which four housing parts are normally used.
One embodiment of the invention will now be
described, by way of example, with reference to the accom-
panying drawings, in which:-
Figure 1 is a plan view of a closure structure
according to the embodiment shown in assembled form around a
cable splice;
Figure 2 is an isometric view of the closure
structure of Figure 1;
Figure 3 is an isometric view of a lower housing
part of the closure structure of Figure 2,
Figure 4 is a cross-sectional view through the
structure taken along line IV-IV in Figure 2; and
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Figure 5 is a view similar to Figure 4 of a
modification of the embodiment.
As shown in Figure 1, a closure structure 10
according to the embodiment is shown in assembled condition
surrounding a splice between two cables 12 and 14 issuing
from either end of the structure.
As is more clearly shown in Figures 2 and 3, the
structure 10 comprises two identical housing parts 16. Each
housing part 16 has a wall means comprising an inner wall 18
which surrounds an opening 20, and an outer wall 22. The
outer wal~ is spaced outwardly from the inner wall which it
surrounds and also away from the opening 20, as can be seen
from Figure 3. The inner and outer walls have coplanar free
end surfaces 24 and 26 respectively, the surface 26 of the
outer wall being formed by an outwardly projecting flange 28.
Each housing part 16 is integrally molded from suitable
plastics material with the walls 18 and 22 integral with a
base 30 from which both of the walls extend as shown in
Figure 4. The inner wall 18 may extend from the junction
region of the base with the outer wall 22 as shown by Figure
4 or, alternatively, may extend from the wall 22 itself as
shown in the modification in Figure 5. Alternatively, the
inner wall may extend from the base in a position spaced from
the junction of the base with the outer wall. This modifica-
tion is not shown in the drawings. As can be seen clearlyfrom Figures 4 and 5, the walls diverge so that they are
spaced apart.
Each housing part has ends and at the ends each of
the walls 18 and 22 defines semi-circular recesses 32 for the
passage of cable in sealing engagement with the housing
parts. Elastomeric seals (not shown) may be disposed around
the recesses to assist in sealing against the surface of a
cable jacket.
One of both of the housing parts 16 (Figure 1) is
formed with locally thinner wall portions 34 in the outer
walls 16, these thinner wall portions being removable for a
purpose to be described.
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In use, after a splice or splices have been made
between the two cables 12 and 14, the two housing parts are
assembled around the cable with sealing gaskets 36 and 38
disposed between opposing inner and outer walls 18 and 22.
In addition, the recesses 32 coact from one housing part to
another for sealing around each cable as it passes through
the ends of the housing parts and into the splice chamber 40
formed between them (see Figure 4). The housing parts are
then secured together by any suitable means, such as bolts 42
passing through aligned holes in the flanges 26 and securing
nuts 44 received by the bolts.
After the housing parts are secured together with
the seals 36 and 38 sealing between the walls 18 and 22, the
thinner regions 34 of the walls 22 are removed and a suitable
moisture blocking material is forced into the space 46 which
is defined by and enclosed by the walls 18 and 22. As will
be readily apparent by considering Figures 3 and 4, the space
46 not only extends along the length of the assembly, but
also between the walls 18 and 22 at the ends so as to be
disposed between adjacent recesses 32 of the walls. A
suitable moisture bloc~ing material is any commercially
available viscous encapsulant material which is at present
used for encapsulation purposes in dual closure structures
~or cable splices such as a bitumastic or plastic type
encapsulant which solidifies in situ.
Hence, the embodiment shows that the invention is
concerned with a structure which only includes two housing
parts while nevertheless providing the sealing advantages
normally provided by a dual closure structure of separate
housings each having two housing parts. A seal is provided
between the outer walls 22 by the gasket 38 and also between
the walls 18 by the gasket 36. In addition, an extra seal is
provided in the region between the two gaskets 36 and 38 by
the encapsulant material occupying the space 46. It will be
readily apparent that the housing parts are easy and economi-
cal to manufacture by simple molding processes, especially
where these parts are identical as in the embodiment
described. Also, the amount of encapsulant material required
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for the space 46 is minimized because the space 46 is
localized towards and into the region between the two gaskets
36 and 38 while providing the desirable sealing effect which
is normally associated with conventional dual closure
structures.
