US2297471A - Cable terminal - Google Patents

Description

sept 29, 1942- F. GUTzMANN ErAL 2,297,471

CABLE TERMINAL Filed Sept. 25, 1940 Patented Sept. 29, 1942 cms mamar.

Fritz Gutmann,

Erich Schuine October Schoneielie, near Herrlnren. vested in the Property Application September 25, 194|, f` In Germany msm* Serial No. 358,32. 1l, 1.39

s mm. (ci. 174-73) This invention relates to the construction of the terminals cables. More particularly, the invention is concerned with cable terminals of the kind having a ceramic tube arranged to distribute the electric stress uniformly and to obviate puncturing or flashing-over. If nevertheless -over occurs then the ceramic tube, acting as a glide path therefor, prevents danger of ilre.

'I'he invention consists in certain features of novelty that will appear from the following description and be particularly pointed out in the appended claims, reference being had to the accompanying drawing, which shows a longitudinal section of one embodiment of the invention.

The cable terminal illustrated by way of example has a tubular outer conductor 4 and a stranded inner conductor 1, embedded in an elastic insulation 2 which consists of a highly polymeric hydro-carbon compound of low dielectric losses. Over the end of insulation 2 a ceramic tube I is inserted which closely fits upon the insulation 2 with a view to avoiding any air cavity between the two. In order to provide for readily inserting the tube I over the insulation 2, the insulation is cleaned off with benzine. A band 3. made of the same material as the insulation 2, is wound around it to form a conical coil whose peripheral surface extends from tube I to' the insulation 2. This coil aids in supporting the outer conductor which is inserted over that end of tube I against which the coiled band 3 bears, and is pressed against the parts I, 3 by a clamp 5. Band 3 is coiled around the insulation 2 so ilrmly as to avoid air cavities forming between the two. In this way, any air cavity between conductor I and insulation 2 will be precluded. Tube I has a torus 9 and is provided with a metal coating Il between this torus and the coiled band 3.

The free end of the cable carries a clamp 6. The strands of conductor I are each tted with a cable eye I and are fixed to the clamp 6 by means of the eyes 8 and of screws I0. They are thus arranged in rosette fashion. This arrangement acts to conduct the arriving heat effectually away and owing to the several cable eyes I also acts -to decrease the detrimental inuence of the skin effect of the soldered joints compared with a single soldered joint. It is attributable to this arrangement alone that the thermal stress at the junction points of the cable is not higher than it is within the cable. Experiments have shown that in the case of a single cable eye into of cables, especially high frequency mere working current of the cable can destroy the strands within the ,cable m.

Owing to the torus l the spark-over voltage between the clamps l, l is several times, say 5 or 6 times, greater than otherwise. v

What is claimed is:

1. A coaxial cable termination comprising an inner cable conductor, an insulating body of solid, elastic, insulating material encircling said inner conductor, a ceramic tube encircling said insulating body, said tube having an outwardly projecting torus on the external surface thereof adjacent one end thereof and the inner diameter of slightly less than the external and substantially and said body are eliminated, an outer cable conductor, at least a portion of said outer conductor encircling a portion of said tube at said one end thereof, and junction termination means for said inner con- `ductor mounted on the other end of said tube.

which the entire inner conductor is soldered the u 2. A coaxial cable termination according to claim 1 wherein said solid, elastic, insulating material is a highly polymeric hydrocarbon compound.

3. A coaxial cable termination according to claim 1 further comprising a conductive coating on the exterior surface of said tube between said torus and the end of said tube encircled by said outer conductor.

4. A coaxial cable termination comprising an inner cable conductor having a plurality of strands, an insulating body encircling said inner junction means comprising separate spaced terminals conductively interconnected for at least a plurality of said stran 5. A coaxial cablev termination according to claim 4 wherein said means comprises a clamp of conductive material and said terminals comprise screws threaded tosaid clamp and further comprising cable eyes fitted to said strands and fastened by said'screws.

6. A coaxial cable termination comprising an inner cable conductor, an insulating body of solid, elastic, insulating material encircling said inner conductor, a ceramic tube encircling said in sulating body, said tube having an outwardly projecting torus on the external surface ,thereof adjacent one end thereof and the inner diameter oi said tube being Slightly less than the external diameter of said body in free space whereby said body is compressed by said tube and substantially all cavities between said tube and said body are eliminated. an outer conductor having a. normal portion and a flared portion, the inner diameter or said normal portion being substantially equal to the external diameter oi said body and less 10

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