Hermetically sealed joint cover for fibre optic cables

An hermetically sealed joint cover for fibre optic cables which does not require the use of mastic and/or miscellaneous sealants, the hermetic seal being achieved by a seal gasket which is provided with at least one through hole partly open outwards and embracing each cable or series of cables entering and/or leaving the joint cover, and which is insertable into seats formed in apertures for the entry and exit of the cables into and from the joint cover.

BACKGROUND OF THE INVENTION 
This invention relates to an hermetically sealed joint cover for fibre 
optic cables, comprising substantially a cable-joining box element and at 
least one entry aperture and one exit aperture for the cables, said cable 
entry and exit apertures being provided in a base connectable to a cover 
along respective connection surfaces to form said box element, within said 
apertures there being provided a seal gasket of elastic material provided 
with at least one through hole and deformable so as to fill the apertures 
as an interference fit when said cover is connected to said base. 
The hermetical seal is a main feature for the correct operation of the 
above joint covers. 
In known types of joint cover this seal is obtained using mastic spread 
along the connecting surfaces of the base and cable. However, with mastic 
the pressure under which the constituent elements of the joint cover are 
fitted together is decisive for proper sealing. 
If the joint cover has to be reopened, the application of new mastic for 
resealing has to be preceded by the removal of all traces of mastic 
remaining on the connected parts. This requires time, and in addition the 
necessary sealing of the joint cover cannot be ensured. 
Moreover in known joint covers it is difficult to insert more than one 
cable while maintaining the seal gaskets in place between the base and 
cover. 
The object of the present invention is to obviate these drawbacks by means 
of a simple joint cover structure which is easy to assemble and install. 
SUMMARY OF THE INVENTION 
This object is attained by an hermetically sealed joint cover for fibre 
optic cables comprising substantially a cable-joining box element and at 
least one entry aperture and one exit aperture for the cables, said cable 
entry and exit apertures being provided in a base connectable to a cover 
along respective connection surfaces to form said box element, within said 
apertures there being provided a seal gasket of elastic material provided 
with at least one through hole and deformable so as to fill the apertures 
as an interference fit when said cover is connected to said base, 
characterised in that said through hole is partly open outwards to receive 
said cable to be joined, in said entry and exit apertures there being 
provided seats for receiving said seal gasket. In this manner the joint 
cover according to the present invention does not require mastic or 
similar sealants to achieve optimum hermetic sealing.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
With reference to the figures, the joint cover/according to the invention 
is of the hermetically sealed type for cables such as for 
telecommunications, and more particularly for fibre optic cables. 
The joint cover 11 comprises substantially a box element for joining single 
cables 12 or multiple cables 13 in a cable entry aperture 14 and a cable 
exit aperture 15, and/or vice versa, formed in a base 16. 
The cable-joining box element comprises a base 16 and a cover 17 which can 
be connected together along a first connection surface 18 and a second 
connection surface 19. 
Both the first connection surface 18 and the second 19 are flat and 
superposable. 
The second connection surface 19 comprises a seat 20 within which a seal 
gasket of O-ring type 21 is inserted. 
In the base 16 there are also provided a pair of shaped seats 22 each 
containing a seal gasket 23 or 24. 
The seal gasket 23 of FIGS. 1, 2, 5, 6 comprises an elastic material 
element with a through hole 25 which is partly open outwards by means of a 
longitudinal cut 26 to facilitate the insertion of the cable 12, and with 
an upper gap 27 formed in the material of the gasket and facing said 
second connection surface 19 of the cover 17. 
The size of the gap 27 in the material depends on the diameter of the 
relative through hole 25 through which the cable 12 to be joined within 
the joint cover 11 passes. 
When the hole 25 is engaged by the cable 12 the deformation undergone by 
the hole because of the interference is of an amount such as to nullify 
the gap 27 and make the connection surfaces of the base 18 and cover 19 
also perfectly flat along the gasket 23 so as to be able to adhere one to 
the other with the necessary seal. 
The sealing action is enhanced by the gasket of O-ring type 21, which is 
more rigid than the elastomeric material of the gasket 23 and presses into 
it when the base 16 is connected to the cover 17. The shaped seats 22 in 
the base for the seal gaskets 23 and 24 are of conjugate shape to said 
seal gaskets 23, 24 and are dimensioned such that the gaskets fit into 
them with slight interference. 
The shaped seats 22 facilitate the insertion of the gasket into the base 16 
and help the sealing action. This sealing is improved by the fact that as 
soon as the cover 17 is connected to the base 16, compression forces with 
a mainly radial component are developed to directly act on the sheath of 
cables. 
The longitudinal cut 26 in the gasket 23 allows rapid positioning of the 
cable 12 in the through hole 25 and also improves this seal and the 
overall hermetic sealing of the joint cover according to the present 
invention. 
FIGS. 3,4, 7 and 8 show how a joint cover according to the invention also 
solves the positioning and joining problem for multiple cables 13. 
For this purpose the seal gasket 24 comprises several through holes 28, at 
least two of which, namely the upper ones, comprise longitudinal cuts 29 
for the insertion of the cables 13. The cut can be lacking in the lower 
hole 28, in which case the relative cable is the first to be inserted, 
this being done with minimum force. 
It will be apparent that in both embodiments the number of apertures, 
holes, gaskets etc. can be changed without leaving the scope of the 
invention. 
By virtue of the provision of U-shaped outer wall portions 30 and inner 
wall portions 31 (FIG. 5) the seats 22 assume a recessed shape which makes 
the position of the relative gasket 23, 24 more stable and improves its 
seal.