US 4,328,394 AGranted

Bonded sheath cable

AssigneesBell Telephone Laboratories, Incorporated, Western Electric Company, Inc.

InventorsCharles J. Aloisio, Jr., George S. Brockway, II, Alvin C. Levy, Randy G. Schneider, George M. Yanizeski

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Abstract

A cable which is capable of being made in a large pair size and yet which has excellent mechanical properties that maintain its integrity notwithstanding extremes in temperature during installation and shipping as well as during the rigors of installation includes a sheath system having a corrugated steel outer shield that is adhesively bonded to a plastic jacket. The corrugated steel shield which is formed to have a longitudinal overlapped seam that is preferably unsealed encloses an aluminum inner shield that in turn encloses a multiconductor core. Advantageously, the sheath system includes a plastic jacketing material which is capable of resisting biaxial stresses which are aggravated in a bonded sheath system. This results in jacket integrity about the longitudinal seam of the outer shield notwithstanding a notched cross-section and an unsupported bridged portion of the plastic jacket adjacent to the seam. Of additional benefit is a further characterization of the plastic as being one which because of its relatively low elastic modulus at conventional extrusion times and temperatures is caused to substantially fill the corrugations of the outer shield. The jacket plastic forms a surface-to-surface bond with the shield that is sufficient to prevent delamination of the outer shield and the jacket and to prevent buckling of the jacket during exposure to temperature extremes.

Claims14

Dependent claims

A bonded sheath cable, which comprises:

a core which includes at least a plurality of individually insulated electrical conductors;
and
a sheath which encloses and which is juxtaposed with said core, said sheath including:
a corrugated shield which is made of metallic material characterized by a modulus of elasticity in the range of about 27-33.times.10.sup.6 psi, which has a relatively high stiffness, and which encloses said core, said shield having inwardly and outwardly facing major surfaces with an overlapped seam having overlying and underlying portions formed between overlapping adjacent longitudinal edge portions of said shield, said shield being formed with at least the longitudinal edge portion of the inwardly facing surface of said overlying portion being substantially juxtaposed to the outwardly facing surface of the underlying portion of said shield;
and
a jacket which is made of a plastic material and which is adhesively bonded to substantially all of said outwardly facing surface of said corrugated metallic shield with a bond strength which is sufficient to prevent delamination and buckling of the sheath in a temperature range of about -15.degree. C. to about 70.degree. C., said jacket plastic which is notched circumferentially by said corrugated shield and longitudinally by said overlapped seam being made of a plastic material having elongation properties sufficient for the jacket to resist rupture caused by corrugation and seam notching when said jacekt is biaxially stressed by forces which are transferred from said shield because of its relatively high stiffness to said jacket in the vicinity of said seam when said cable is installed in said range of temperatures.

3 more elements

A cable which comprises:

a core which includes at least a plurality of individually insulated conductors;
a sheath system which encloses and which is juxtaposed with said core, said sheath system comprising:
a first metallic shield which surrounds said core and which is formed about the core to have a longitudinal seam;
a second shield which is made of a metallic material characterized by a modulus of elasticity in the range of about 30.times.10.sup.6 psi, which has a relatively high stiffness, and which surrounds said first metallic shield, said second shield being corrugated transversely of a longitudinal axis of said second shield, and having inwardly and outwardly facing major surfaces with an overlapped seam being formed between adjacent portions of the major surfaces of said second shield, said overlapped seam having overlying and underlying portions with at least the longitudinal edge portion of said inwardly facing surface of said overlying portion being substantially juxtaposed to said outwardly facing surface of said underlying portion of said second shield, and said second shield having at least its outwardly facing major surface precoated with an adhesive-like material;
and
a jacket which is made of a plastic material and which is adhesively bonded to substantially all of said outwardly facing surface of said corrugated metallic shield with a bond strength which is sufficient to prevent delamination and buckling of the sheath in a temperature range of about -15.degree. C. to about 70.degree. C., said jacket plastic which is notched circumferentially by said corrugated shield and longitudinally by said overlapped seam being made of a plastic material having elongation properties sufficient for the jacket to resist rupture caused by corrugation and seam notching when said jacket is biaxially stressed by forces which are transferred from said second shield because of its relatively high stiffness to said jacket in the vicinity of said overlapped seam when said cable is installed in said range of temperatures.

3 more elements

Dependencies are inferred from the claim text.