ENVELOPPES IGNIFUGES POUR CONNEXIONS DE CABLES ELECTRIQUES

FLAMEPROOF CASINGS FOR CABLE CONNECTIONS

Abrégé anglais

ABSTRACT OF THE DISCLOSURE

In flameproof casings made of molded plastic for cable
connections in telecommunications and power distribution, cable
sleeves in particular, a thermoplast molded plastic cover is
provided with a dimensionally stable sheath made of a non-combustible
material which is highly inflammable and is inert to thermoplasts.
The sheath which may be a wire net can also have a coating made of
water glass, silicone plastic, a non-combustible plastic which is
highly flame resistant or a foaming fireproofing material.

Revendications

CLAIMS

What is claimed is:

1. Flameproof casing made of thermoplast molded plastics for cable
connections in telecommunications and power distribution systems,
comprising:

(a) a cover made of thermoplast molded plastic; and

(b) a dimensionally stable, non-combustible sheath of low
flammability which is inert to the thermoplast molded plastic.

2. Flameproof casing according to claim 1, wherein said sheath is
impermeable.

3. Flameproof casing according to claim 2, wherein said sheath is a
metal film.

4. Flameproof casing according to claim 1, wherein said sheath has
small fissures.

5. Flameproof casing according to claim 4, wherein said sheath is a
non-combustible web.

6. Flameproof casing according to claim 5, wherein said sheath
comprises a wire net.

7. Flameproof casing according to claim 5, wherein said sheath
comprises a web made of metal.

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8. Flameproof casing according to claim 1, wherein said
sheath is porous.


9. Flameproof casing according to claim 1, 2, or 4, wherein
said sheath further includes a non-combustible plastic of low
flammability.


10. Flameproof casing according to claim 1, 2, or 4, wherein
said sheath further includes a silicate.


11. Flameproof casing according to claim 1, 2, or 4, wherein
said sheath further includes a foaming fireproofing material.


12. Flameproof casing according to claim 1, wherein said
casing comprises a cable sleeve for cable connections.


13. Flameproof casing according to claim 6, 7 or 8 wherein
said sheath further includes a non-combustible plastic of low
flammability.


14. Flameproof casing according to claim 6, 7 or 8, wherein
said sheath further includes a silicate.


15. Flameproof casing according to claim 6, 7 or 8, wherein
said sheath further includes a foaming fireproofing material.

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Description

3~

BACKGRO WD 0~ TH~ VENTICN

The inverItion reiates to flame~roof casings r~de of
the~oplast molded plastics for cable connections in
teleco~unications and power distribution systems, in particular for
cable sleeves and cable terminals.

Cable sleeves made of plastic as casings for cahle connections
in teleco~unications have heen knnwn for some time. The great
advantage of cable sleeves made, preferably, of a thermoplast molde~
plastic derives from their easy processability, their elasticity,
their low weight, their freedom from corrosion, their lnw
per~Rahility to ~ases, their extremely high resistance to violent
external ~orces, such as stress due tn impact or falling, their
ahsolute protection against accidental contact with electrical
voltages and their economical manufacture. Cable sleeves made of
thermoplast ~olded plastic, preferably a polyolefine are resistant
to a great number of chemical substances. Casings -- for example,
cahle sleeves -- made of therMnplast ~olded plastic will, however,
~e destroyed in a ~el~y short time by the external effect of fla~es.
As a result of ruptures in the sleeve casin~, flanes can penetrate
to the cable connections, by which means the telecommunications
t.ansmission or power distribution can be interrupted. Even in the
case of flame-resistant thermoplast ~olded platics, this process
cannnt be prevented, since the te~erature in every case exceeds
4nnC, which is above the melting and softening temperatures for
thermoplast ~olded plastics. This is particularly true nf the
thermoplast molded plastics which, because of the above-mentioned
characteristics, are used in cah]e sleeves.


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SU RY nF THE INvENTION

It is an ob~iect of the present invention to provide casings
made of thermoplast molded plastics for cable connections in
telecommu;cations and power distribution, in particular cable
sleeves, that prevent a destruction of the cable cnnnectinns under
the influence of external flames.

This purpose is accomplished, according to the invention, ~y
means of a cover ~ade of thermoplast molded plastic, which includes
a sheath that is dimensionally stable and non-combustible and is of
low flammability. The ~heath is inert w~th regard to the
ther~oplast molded plastic. It can he i~pervious, have s~all
fissures, or be porous. Casings equipped with a sheath in
accordance with the invention are resistant to the external effects
of flames. Ahove all, casin~s equiPped in accordance with the
invention retain their outside shape when exposed to external
effects of flames. Diffusion flames are dissipated on the surface
nf the sheath.
Other features and advantages of the invention will be
apparent ~rom the followina description of the preferred
embodiments, and from the claims.

For a full understanding o~ the present invention, ~eference
should now he made to the following detailed description of the
preferred embodiments of the invention and to the accompanying
drawings.



~2~

B~IEF DESCRIPTION CF THE ~PAWINGS

Figs. 1 and 2 show views of cable sleeves with sect~ons cut
away.




Fig. 3 shows a section through a ca~le sleeve with a seal.




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D~AILED DESCRIPTI~

With reference to Figs. 1 and ~ there is shown a wire nRt lO
with a coating 11 wrapped around a ther~oplast cable sleeve 2
comprising a sheath 1. In order to cover the front end area, that
is, the area where the cable is introduced, the sheath 1 extends up
to the cable ~. In order to give stability to the front end section
4 of the sheath 1, a wire 5 has ~een introduced.

Fig. 3 shows a cable sleeve with a seal 7, consisting of an
element made of thermoplast molding plastic 89 which is provided
with a flameproof surface sheath 9, pursuant to the invention, to
fireproof the end of a ca~le 6.

If the design of a cahle sleeve in accordance with the
invention includes a seal 39 this too can ~e protected from flames
in accordance with the invention.

Suitable sheaths includes metal films ~ith a thickness of
fron n.n2 to 0.5 m~. Preferably, an aluminum fil~ which is provided
~ith an adhesive or has a polymer coating is used. In the latter
case, the film can be welded through a heating process onto the
sleeve.

It is particularly advantageous to use a web or net made of
~etal wire for the sheath. In this case the width of the mesh of
the weh or net should preferably be between O.l and 5 mm. The web
or net should ideally be made of a corrosion-resistant material~
such as aluminum, galvanized or nickel-plated steel or co3per.


~ ~ ~ 3t~ 1

Accordinq to a preferred e~bodi~ent of the 1nver,tion, the
sheath can cons~st of a web or r-~t made of metal wire and of a
silicate or non-combustible plastic that is highly fla~e resist3nt.
The latter can if necessary be applied to a substrate. Suitable
materials include hardenable plastics a coating of silicone plastic
or water glass. The coating can also consist of a foaming
firepronfin~ ~aterial. Accordinn to another advantageous for~ of
the inventinn, the web or net is ~ade of Nirosta' ) and coated
with a non-combustible plastic that is highly flame resistant. nere
tno, coatinas ~ade of hardenable plastics, silicon plastic or
foaming fireproofing ~aterlals have proved effective.

E~hodi~ents in accnrdance with the invention, which oan be
~anufactured according to any desired process, are being
successful]y used as casinas for cable connections. They are being
used particularly in cable sleeves and also for seals that can be
used in cable sleeves. In every case, excellent fireproofing
against the external effects of flame is achieved.

There has thus been shown and described novel fla~eproof
casings for cable connections which fulfills all the object and
advantages sought therefor. Many changes, ~odifications, variations
and other uses and applications of the subjec~ invention will,
however, heco~e apparent to those skilled in the art after
considering this specification and the accGmpanying drawings which
disclose preferred embndi~ents thereof. All such changes,
modifications, variations and other uses and applications which do
not depart from the spirit and sco~e of the invention are dee~ed to
be covered by the invention which is limited only by the claims
which follow.