US1763873A - Telephone cable - Google Patents

Description

June 17, 1930. w, WESTON 1,763,873

TELEPHONE CABLE Filed Feb. 16, 1929 Patented June 17, 1930 UNITED STATES PATENT OFFICE WILLIAK K. WESTON, OF SANIPERSTEAD, ENGLAND, ASSIGNOB WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK TELEPHO Application filed February 16, 1929, Serial No This invention relates to electric telephone communication cables of the type in which a multiplicity of conductors are bundled together. In cables where circuits for 4-wire repeater operation are used the quads which are used for transmitting in opposite directions may be separated into different layers, or they may form two halves of the same layer. In the latter case it is usual to place the quads transmitting in one direction togcther in one half of the layer, and those for transmitting in the other direction in the other half of the layer. One or more separator quads have been placed between the end quads of the two groups so as to prevent interference between the end quads of the groups. Analternative practice has been to place a. metallic screen between the groups in place of the separator quads.

With the first arrangement the necessity of using separator quads is frequently not economical; the second arrangement of using a metallic screen has the relative disadvantage of not being convenient to apply mechanically, on account of the weakness of the metal foil, which is only with difficulty stranded into the layer. Further, the proximity of the metal screen to the adjacent quads tends to increase the capacity of these quads.

The present invention is concerned chiefl with an improved screen which rovides bot suflicient strength to permit 0 satisfactory stranding and also provides adequate separation between the screen and the adjacent quads to reduce the capacity effect of the metal foil.

In the following detailed description of certain embodiments of this invention reference will be made to the attached drawing in which Fig. 1 1s a simplified showing ofa crosssection of a telephone cable in which sepa- L rating screens are provided in accordance with the invention; and v Fig. 2, a, b and c show different types of separating strands made up in accordance with the invention.

In the telephone cable 10 shown in Fig. 1 only a single la er of quads has been shown for the sake o simplicity. The quads 11 NE CABLE 340,527, and in Great Britain um 29,1928.

forming approximately one half of the layer are arranged for repeater operation in one direction, whereas the quads 12 occup ing the other half of the layer are arrange for repeater operation in the opposite direction. In order to prevent interference between end quads, such as 11 and 12*, of the two groups, separating strands, such as 13 and '14, each containing a metallic screen are inserted in the layer between neighboring quads of the groups. It should be understood that several other layers of quads, or pairs, or other units, may be arranged within the cable besides the layer shown in the figure; the conductors may be confined within any of the well known types of envelopes such as a lead sheath; and the different layers may, if necessary, be shielded fromeach other by any known means.

In Fig. 2 there is shown three different types of screening strands which may be used for the strands 13 and 14 of Fig. 1. The strand is composed of a screening element 20, which may be in the form of a thin metal. tape, and of one or more reenforcing elements 21 placed on one or both sides of the metal tape. In the preferred form the reenforcing element is, made of paper which may be fold-- ed, crimped or twisted into strips and longitudinally disposed with respect to the metal tape 20 to provide strength. The crimping or folding serves to extend the dimension of the reenforcing element transversely with respect to the metal tape in order that it may provide additional separation between the screening element and the adjacent quads in the cable.

The unit consisting of the crinkled paper, or papers, and the metal foil is preferably served with a spiral lapping of paper 22 so applied as to completely cover the screen. in-

sulate it and keep the component parts of the unit in their proper relationship. The form ofthe separating strand may, therefore, have the appearance, in cross-section, of a rectangle or an ellipse.

Instead of the longitudinally disposed reenforcing strip being of paper it may be of any other. similar material provided it gives the requisite strength and spacing.

What is claimed is:

1. In a telephone cable, insulated wires, a

spacing strand between two of said wires comprising a substantially straight metallic screening tape and a reenforcing strip of iiisulating material disposed longitudinally of said tape.

2. In a telephone cable, insulated wires, a spacing strand between two of said wires comprising a metallic screening tape and a reenforcing strip of insulating material shaped to introduce a plurality of continuous air spaces between said strip and one of said wires.

3. In a telephone cable, a plurality of wires, a spacing strand between two of said wires comprising a metallic screening tape, a reenforcing strip for said tape of insulating material, andan outer serving of insulating material for maintaining said tape'and said strip in a fixed mutual relation.

4, In a telephone cable, a plurality of wires,

a spacing strand between two of said wires comprising a metallic screening tape, a reenforcing strip for said tape of insulating material, and an outer serving of insulating material for maintaining said tape and said strip in a'fixed mutual relation, said reen forcing strip being folded to introduce a plurality of air spaces within said serving.

In witness whereof, I hereunto subscribe my name this twenty ninth day of January,

WILLIAM KIRBY IVESTON.

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