Electrical cable with open helix screen wires electrically contacting a longitudinal wire and manufacture thereof
AssigneeSocietaa Cavi Pirelli S.p.A.
InventorsCarlo Marin, Cesare Seveso
Life of this patent
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Abstract
An electrical cable with a core comprising an electrical conductor surrounded by insulation and with both a screen of wires in open helix configuration on the core and at least one other wire extending longitudinally of the core and electrically contacting the wires of the screen. An insulating sheath surrounds the screen and may itself embed the wires or it may surround a layer of extruded material which at least partially embeds the wires. The material of the layer may be insulating or semi-conductive. Also, a process for manufacturing such cable.
Claims11
In an electrical cable comprising a cylindrical core which is formed by at least one electrical conductor with extruded insulation therearound and comprising a screen upon said core formed by a plurality of metal wires applied to said core along paths conforming to an open helix, the improvement comprising at least a further metal connecting wire which extends longitudinally along a path which is undulated with respect to a generatrix of said core, which extends in the direction of and parallel to a generatrix of said core, which extends transversely to said paths of said plurality of metal wires without encircling said core and which is in electrical contact with all the wires of said screen, and a layer of extruded material around said core and at least partially embedding said wires of said screen and said further metal connecting wire whereby said wires of said screen and said further connecting wire are held in their respective positions by said layer.
Process for applying a screen of metal wires in an open helix configuration around the core of a cable comprising:
- while longitudinally advancing a core, depositing on the core a plurality of parallel metal wires while producing relative motion between said wires and the core in alternately different directions circumferentially of the core to cause said wires to follow paths conforming to an open helix configuration;
- and
- before so depositing said plurality of metal wires on the core and while so advancing the core, depositing at least one other metal wire on the core in electrical contact with all said plurality of metal wires, said one other metal wire being deposited along a path which is undulated with respect to a generatrix of the core, which extends longitudinally and in the direction of and parallel to the generatrix of the core and which extends transversely to the paths of said plurality of parallel metal wires without encircling said core;
- and
- at the point where said plurality of metal wires are deposited on the core, extruding a layer of material over said plurality of metal wires.
Process for applying a screen of metal wires in an open helix configuration around the core of a cable comprising:
- while longitudinally advancing a core, depositing on the core a plurality of parallel metal wires while producing relative motion between said wires and the core in alternately different directions circumferentially of the core to cause said wires to follow paths conforming to an open helix configuration;
- and
- after so depositing said plurality of metal wires on the core and while so advancing the core, depositing at least one other metal wire on the core in electrical contact with all said plurality of metal wires, said one other metal wire being deposited along a path which is undulated with respect to a generatrix of the core, which extends longitudinally and in the direction of and parallel to the generatrix of the core and which extends transversely to the paths of said plurality of parallel metal wires without encircling said core;
- and
- at the point where said at least one other metal wire contacts said plurality of metal wires, extruding a layer of material over said plurality of metal wires and said at least one other metal wire.
Dependencies are inferred from the claim text.