GB2027083A

GB2027083A - Electrical, Multicore Flexible Sheathed Cable

Info

Publication number: GB2027083A
Application number: GB7923893A
Authority: GB
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 1978-07-14
Filing date: 1979-07-09
Publication date: 1980-02-13
Also published as: SE446137B; FR2431168A1; SE7906105L; DE2831493C2; IT7924266A0; FR2431168B1; GB2027083B; IT1122127B; DE2831493A1

Abstract

In order, in flexible sheathed cables, to save a stranding step, the individual wires (10) of conductors (20) intended to be stranded together are guided parallel to each other into an extruder (16) which applies an insulating sheath to the wires so as to form a sheathed conductor. Stranding of the sheathed conductors then takes place to form the cable, and retroactively (or by feedback) during the stranding of the conductors (20), stranding of the wires in each conductor is effected without twisting-back and at a greater lay length than that of the stranded conductors. <IMAGE>

Description

SPECIFICATION A Multicore Flexible Sheathed Electrical Cable This invention relates to a multi-core flexible sheathed electrical cable comprising conductors stranded together, each conductor comprising a plurality of individual wires.

For various purposes, for example for connecting cords for apparatus and the like, the electrical, multi-core flexible sheathed cables in the low-voltage zone comprise fine-wire conductors, so-called stranded conductors. Two to five of these stranded conductors (stranding elements) are stranded to provide the line or power core with a lay length of approximately 20 to 40 cm.

The individual stranding elements, the stranded conductors, are built-up from a plurality of individual wires, for example from 32 individual wires each having a diameter of 0.25 mm, for a stranded conductor having a cross-section of 1.5 mm2. In known lines of this type, the individual wires are stranded approximately with the same lay length as the line or power core.

It is an object of the invention to simplify the manufacturing process of such multi-core flexible sheathed cables by changing the build-up of these lines in such a way that the stranded lay length of the line or power core is smaller than the stranded lay length of each stranding element designed as a stranded conductor.

If the multi-core flexible sheathed cable is so built-up that the individual wires of each stranding element have a substantially greater lay length than the lay length of the line or power core, the line may be manufactured in accordance with a process whereby the individual wires of a stranded conductor (constituting a stranding element of the line), upon enveiopment of the stranded conductor with an insulating layer, travel parallel into an extruder and form a plurality of thus manufactured stranded conductors which, without retro-active or feedback action constitute stranding elements of the electrical, multi-core line or power core.

In this final stranding of the stranding elements taking place without twisting-back, in fact, the individual wires which are combined to form a stranding element and which initially are guided parallel without any stranding and are surrounded by a sheathing, are so twisted relative to each other as to produce indirect stranding having a lay length which is however substantially greater than the lay length of the line or power core. The stranding of the individual wires required in the harmonising regulations of the corresponding German Standard VDE 0281 (and also the corresponding foreign standards) is in this way satisfied without it being necessary to carry out a stranding process during the manufacture of the conductors.Thereby, apart from this relatively costly working step there are also avoided the losses (due to expansion of approximately 3%) occurring during the bunch-stranding of fine-wire copper conductors in consequence of tensile stressing of the individual wires.

Consequently, the method may, in detail, be so carried into effect that initially from the pay-off framework the individual wires subsequently constituting conductors are fed parallel to an extruder, in which the conductor or core insulation is applied. Subsequently, these conductors can, if a plurality of extrusion devices is set up side-by-side, be directly stranded in online operation to afford the finished line.

The invention will now be described in detail, by way of example only, with reference to the accompanying diagrammatic drawing.

The drawing shows the manufacture of a conductor 20 (stranding element, stranded conductors) assembled from individual wires 1 0.

The individual wires 10 travel-off from appropriate supply reels 11, are deflected via rollers 12 and are then fed in parallel arrangement to a strainer plate 13. Thereupon, they are guided in parallel to a nipple 14 in which they are formed to a substantially round structure and are then fed to a coating station formed by the injection head 1 6 of an extruder 1 5. The finish-extruded conductor 20 consequently comprises a multiwire stranded conductor of individual wires 10 extending parallel to each other and sheathed by insulating means. (In the cases achieved, the number of individual wires is relatively large, for example 32 in the case of a stranded conductor having a cross-section of 1.5 mm2).

In the case of the conventional stranding process (not shown in the drawing), for example of three conductors to afford a line or power core, the cores are stranded without twisting-back (untwisting). As this is done for the conductors 20, the individual wires 10 are so twisted relative to each other within each insulated conductor that it corresponds to stranding with a lay length greater than the lay length of the stranded line itself.

Claims

1. A multi-core flexible sheathed electrical cable composed of a plurality of electrical conductors stranded together, each conductor comprising a plurality of wires stranded together, in which the lay length of each stranded conductor is less than the lay length of the wires stranded together in the conductor.

2. A method of making a multi-core flexible sheathed electrical cable composed of a plurality of electrical conductors stranded together, each conductor comprising a plurality of wires stranded together, in which the individual wires of each conductor are guided parallel to each other to a coating station at which an insulated sheath is applied to the wires to form a sheathed conductor, and a plurality of sheathed conductors are stranded together with a given lay length to form the electrical cable and in such a way that the wires in each conductor are also stranded together at a greater lay length.

3. Electrical, multicore flexible sheathed cable comprising a series or row of stranding elements,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION A Multicore Flexible Sheathed Electrical Cable This invention relates to a multi-core flexible sheathed electrical cable comprising conductors stranded together, each conductor comprising a plurality of individual wires. For various purposes, for example for connecting cords for apparatus and the like, the electrical, multi-core flexible sheathed cables in the low-voltage zone comprise fine-wire conductors, so-called stranded conductors. Two to five of these stranded conductors (stranding elements) are stranded to provide the line or power core with a lay length of approximately 20 to 40 cm. The individual stranding elements, the stranded conductors, are built-up from a plurality of individual wires, for example from 32 individual wires each having a diameter of 0.25 mm, for a stranded conductor having a cross-section of 1.5 mm2. In known lines of this type, the individual wires are stranded approximately with the same lay length as the line or power core. It is an object of the invention to simplify the manufacturing process of such multi-core flexible sheathed cables by changing the build-up of these lines in such a way that the stranded lay length of the line or power core is smaller than the stranded lay length of each stranding element designed as a stranded conductor. If the multi-core flexible sheathed cable is so built-up that the individual wires of each stranding element have a substantially greater lay length than the lay length of the line or power core, the line may be manufactured in accordance with a process whereby the individual wires of a stranded conductor (constituting a stranding element of the line), upon enveiopment of the stranded conductor with an insulating layer, travel parallel into an extruder and form a plurality of thus manufactured stranded conductors which, without retro-active or feedback action constitute stranding elements of the electrical, multi-core line or power core. In this final stranding of the stranding elements taking place without twisting-back, in fact, the individual wires which are combined to form a stranding element and which initially are guided parallel without any stranding and are surrounded by a sheathing, are so twisted relative to each other as to produce indirect stranding having a lay length which is however substantially greater than the lay length of the line or power core. The stranding of the individual wires required in the harmonising regulations of the corresponding German Standard VDE 0281 (and also the corresponding foreign standards) is in this way satisfied without it being necessary to carry out a stranding process during the manufacture of the conductors.Thereby, apart from this relatively costly working step there are also avoided the losses (due to expansion of approximately 3%) occurring during the bunch-stranding of fine-wire copper conductors in consequence of tensile stressing of the individual wires. Consequently, the method may, in detail, be so carried into effect that initially from the pay-off framework the individual wires subsequently constituting conductors are fed parallel to an extruder, in which the conductor or core insulation is applied. Subsequently, these conductors can, if a plurality of extrusion devices is set up side-by-side, be directly stranded in online operation to afford the finished line. The invention will now be described in detail, by way of example only, with reference to the accompanying diagrammatic drawing. The drawing shows the manufacture of a conductor 20 (stranding element, stranded conductors) assembled from individual wires 1 0. The individual wires 10 travel-off from appropriate supply reels 11, are deflected via rollers 12 and are then fed in parallel arrangement to a strainer plate 13. Thereupon, they are guided in parallel to a nipple 14 in which they are formed to a substantially round structure and are then fed to a coating station formed by the injection head 1 6 of an extruder 1 5. The finish-extruded conductor 20 consequently comprises a multiwire stranded conductor of individual wires 10 extending parallel to each other and sheathed by insulating means. (In the cases achieved, the number of individual wires is relatively large, for example 32 in the case of a stranded conductor having a cross-section of 1.5 mm2). In the case of the conventional stranding process (not shown in the drawing), for example of three conductors to afford a line or power core, the cores are stranded without twisting-back (untwisting). As this is done for the conductors 20, the individual wires 10 are so twisted relative to each other within each insulated conductor that it corresponds to stranding with a lay length greater than the lay length of the stranded line itself. Claims

3. Electrical, multicore flexible sheathed cable comprising a series or row of stranding elements, the individual stranding elements comprising a plurality of wires being designed as stranded conductors, characterised in that the stranded lay length of the line or power core is smaller than the stranded lay length of each stranding element designed as a stranded conductor.

4. Process for the -manufacture of a line according to claim 3, characterised in that the individual wires of a stranded conductor constituting a stranding element of the line travel, on enveloping the stranded conductor with an insulating layer, parallel into an extruder and form a plurality of thus manufactured stranded conductors which, without twisting-back, form stranding elements of thg electrical, multicore line or power core.

5. A multi-core flexible sheathed electrical cable substantially as hereinbefore described and with reference to and as shown in the accompanying drawing.

6. A method of making a multi-core flexible sheathed electrical cable substantially as hereinbefore described with reference to and as shown in the accompanying drawing.