Note: Descriptions are shown in the official language in which they were submitted.
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The invention relates to couplin~ devices for co-axial
~ cables, particularl.y co-axial high-frequency cables,
; For coupling co-axial high-frequency cables which
comprise a wire-shaped internal conductor and a cylindrical `.
external conductor separated rom each other by a dielectric
layer, use is commonly made of concentrically structured coupling
elements. To this end, connecting devices situated on the two
.~ cable extremities have already been proposed which were to be
connected together by a co-axial coupling element in such manner
that a connection is established which may be freed mechanically .
and thus also electrically, at any time.
A disadvantaqe of this coupling element is the number
.- and complex design of the components required. It has moreover :~
been found that the clamping action of a slotted sleeve for the ~. ;
internal conductor weakens because the cones used therefor ~ ~
consist of plastics material, which tends to flow in time under ~ : :
~, the action of temperature fluctuations, so that the clamping .
.~ ~ cones can no longer comply mechanically and electrically with:
~ the require~ents for this type of cable. ~
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~ 20 The present invention consists in a releasable coupling~
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: device for connecting together co-axial cable ends provided with ~
connecting devices, comprising a generally tubular external ..
~ casing forming an outer conductor and being threaded at either .
.~ end for connection to the connecting devices, an insulating ~
member of plastics material press-fitted into the external casing .: .
and including at least two hollow internally threaded protuber~
-~ ances for receiving screws for fastening the cable inner con~
'~ ductors, and an inner conductor connecting member disposed
withi.n the insulating member, the external casing having an
openin~, for providing access to the screws, with means for ::
, closing the opening and, at each end a metal face and a ring ~ :~
of resilient material for forming a seal with a connecting.
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device when connected thereto.
The housing of the coupling device and the connecting
devices at the cable extremities may be brought into contact
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at corresponding end faces with the required contact pressure,
quickly, conveniently, by means of the screw-threads~ so that
an uninterrupted connection screwed against interference radi-
ation is produced for the external conductor. Each of the two
metal seals formed between the end faces on screwing tight, are
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complemented wlth a resilient ring, for instance of rubber,
positioned therebetween. The internal conductor ends of the
; cable are reseived by the internal conductor connectlng member
of the coupling device, which is centered in the plastics - ~`
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material insulating member and may be immovably cast in. At
` ~ ~ the same time, the insulating member is anchored by a press fit --~
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~1 in the external housing. To counteract the ageing actions of
the plastics material, the internal conductor extremities of
the cable are screwed tight within the internal conductor con~
necting member of the coupling element, the locking or set
screws being held in the protuberances of the insulating member
and thus being proof against loss during assembling. The ;
screwing operation occurs vla the housing opening which may have
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a screw-thread~and which may be closab~le iD gastight manner by
means of a rubber-sealed~conductive screwable insert.
Preferably the inner conductor connecting memher has
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an internal bore, and holes arranged to line up with the pro- `~
~'~ tuberances o~ the insulating member so as to allow passage of ; ~
the screws. ~-
This results in the possibility of coupling together
~ cable types having differently dimensioned internal conductors.
i.. " 30 Also, the internal bore of the internal conductor connecting
~ ~ member may be provided with recesses opposite the holes, the
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! holes receiving the set screws from the protuberances, so that
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the internal conductor may be anchored firmly within the inter-
nal conductor connecting member. An internal conductor of
smaller diameter than of the bore of the internal conductor `-
connecting member may then be securecl, as the thin internal
conductor is pressed into the recess of the internal conductor
connecting member whilst being screwed tight. A wide range of
types of cables may thus be coupled.
It is advantageous furthermore for the relative
dielectric factor of the insulating member carrying the internal
conductor connecting member to be ~2.5.
The invention will be further described, by way of
example with reference to the accompanying drawing, which is a
side view in part section of a preferred coupling device. The
coupling device comprises a cylindrical metal casing l and an
insulating member 3 situated in its cavity ll, in which an
internal conductor connecting member 2 is cast. The casing 1
comprises two axially aligned openings having an internal screw-
thread 12 for reception of the connecting devices 13 having
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externally screw-threaded stubs. Upon screwing-in the connect- ~ ;
ing stubs 13, at each end of the casing their end faces come
into contact with the respective end faces of the casing at lO,
so that an uninterrupted connection is produced for the external
conductor. The metal to metal seals lO are reinforced by a
rubber seal in the form of a ring 9 positioned between them, so
that the contact point 9, lO is gastight, damp-proof and screened~
against interference radiation. The screwing of the casing l ;
~ and connecting stub 13 may be performed more easily if both ;~ ~
- parts have a hexagonal cross-section having the same size, so ~;
as to make possible to use of a single type of tool. After -
this operation, the insulation 17 of the cable 16 is inserted
L'_ into the already tightly screwed connecting stub 13. By -~
tightening the locking nut 14 on the connecting device, the
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~.C337~
cable adaptor 15 of the connectinq device is coupled to the
connecting stub 13. The internal conductor extremity 18 of
the cable, which extends beyond -the end of the insulation 17
of the cable 16, is thus urged into -the internal conductor
connecting member 2 of the coupling device which is cast in
the plastics insulating member 3, the latter being accurately
centred by virtue of its press fit 19, the insulating member 3
being mounted immediately prior to the forming of the internal
screw-thread 12. The extremities 18 of the internal conductor
of the cable are then immobilised by captive set or locking
screws 5 which are installed in loss-proof m~anner in protuber-
ances 4 situated in the insulating member 3 for the purpose of
simplified assembling operation, these protuberances being
formed at one side of the axis of the cable. A casing aperture
6, which may be closed off by means of an inwardly screwable
insert 7 and sealed off by means of a sealing ring 8 provides
access to the screws. The insulating member 3 has dimensions
such that~ in conjunction with the internal conductor connecting
member 2 of metal and the casing 1, the rated value of the
char~cteristic cable impedance is established. i~
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Various modifications may be made within the scope
~. of the inYention.
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