DE8906828U1 - Shearing cable with increased electrical safety against crushing and impact stress - Google Patents

Description

Feiten & Guilleaume Energietechnik AG, D-5000 Cologne 80

Description:

Screeia ropes with increased electrical safety against crushing, screeia and stress

The invention relates to a shear cable (insulated power cable) with increased safety against crushing and impact stress according to the scope of claim 1. It is used to connect mobile machines under high mechanical stress, primarily in mining.

Cutting cables are well known. For example, in the brochure of Feiten & Guilieaume Energietechnik GmbH Cologne "Insulated cables for mining" 10.81 p. 16-17, several cutting cables of the type NSSHCgEöu with three energy and various control and monitoring wires are described.

Each power wire consists of a flexible conductor made of fine copper wires, surrounded by an insulating sheath made of a rubber compound based on EFR (ethylene propylene rubber) and an outer layer made of a conductive rubber compound. Each control wire consists of an expandable and compressible copper-steel conductor, surrounded by an insulating sheath based on EFF, and each monitoring wire consists of the same conductor, but surrounded by a sheath made of a conductive rubber compound.

The three energy wires and - in their outer gussets - two control wires and a monitoring wire are twisted together. The conductive layers of the energy wires and the conductive sheath of the monitoring wire touch each other. The inner gusset (the gusset between the energy wires and the three gussets between two

Fl 4873 -2- 31.05.89

energy wires and a control or monitoring wire) is free or filled with a conductive and slippery medium such as conductive paste or graphite powder, as specified in DE-GM 78 07 518, for example.

There, a sheathed cable with three synergy cores is described, in which three combined cores - with the structure: control conductor, insulating sheath, concentric monitoring conductor, conductive sheath - are arranged in the outer gusset spaces instead of the three individual control and monitoring cores.

After a foil wrap, the inner sheath made of an electrically insulating and mechanically high-quality rubber compound is applied around the stranded cable. On top of this is the concentric protective conductor made of an armored braid made of copper-steel strands, and finally the outer sheath made of a polychloroprene compound.

The invention is based on the object of further increasing the electrical safety of such shearing cables against crushing and impact stress.

The solution to this problem is specified with the characterizing features of claim 1. It essentially consists in the fact that a monitoring conductor is arranged in the interior of the wires (in the cable core) and the remaining interior is filled with an electrically conductive and mechanically high-quality rubber mixture, which has the shape of a cross that separates the energy wires from one another.

This design significantly increases the electrical safety of the shearing cable against crushing and impact stress. If the cable is damaged by external influences, an electrical contact is initially made between the power wire and the monitoring conductor, which can be detected by a monitoring system in the network before a phase short circuit occurs between the power wires.

Fl 4073 -3- 31. 05.&thgr;&udiagr;

Two embodiments of the invention are shown in the drawing and are described in more detail below. Both figures show a shearing cable with three power wires and three control or monitoring wires in the outer winding spaces, with a monitoring conductor arranged in the interior and the rest of the interior filled with a conductive rubber mixture. In Fig. 1 the shearing cable only has an insulating inner sheath, whereas in Fig. 2 it has an additional, but conductive, inner sheath above the shearing connection.

BezeLehnet are with:

1 energy core, consisting of:

11 Conductor: flexible, fine-stranded conductor made of tinned copper wires

12 Insulation: heat-resistant, mechanically high-quality rubber mixture on EPR (ethylene-propylene rubber) base (3GI3)

13 External conductive layer: EPR-based rubber compound with carbon black additive

2 control wires, consisting of:

21 conductors: stretch- and compression-resistant copper-steel conductor

22 Insulation: EPR-based mixture

23 outer conductive layer: EPR-based mixture with carbon black additive

3 monitoring wires in the outer gusset space, consisting of:

31 ladder: like 21

32 Conductive rubber hü He: as 23

4 monitoring .Interior conductor: special design, tinned copper wires

5 Conductive rubber filling of the interior (conductive rubber cross): mixture based on EPR with carbon black additive

6 Conductive inner sheath: as 5

7 Insulating barrel jacket: SBR (styrene butadiene rubber) based mixture

8 Concentric protective conductor: tensile-resistant armored braid made of copper-steel strands

9 Outer jacket: Polychloroprene compound (5GM5).

In both figures it is essential to note that the monitoring conductor 4 is arranged in the cable core and is connected to a conductive

Fl 4873 -4- 31.05.89

Sheath is surrounded in the form of a cross 5. The three energy wires 1 and the three auxiliary wires 2 and 3 in the outer spaces are stranded above the conductive cross 5. The energy wires 1 are separated from each other by the webs of the conductive cross 5.

If, as shown in Fig. 1, the inner sheath 7 is made of an insulating rubber coating as usual, the conductive cross 5 is in contact with the outer conductive layers or sheaths 13, 23 or 32 of all the wires, so that it forms the monitoring shield with them. This, together with the concentric protective conductor 8 in conjunction with a monitoring device, enables the cable to be monitored for insulation faults and damage caused by external influences.

A further increase in the electrical safety of the shearing cable is achieved if, as shown in Fig. 2, an additional but conductive inner sheath 6 is arranged between the stranded assembly 1-5 and the insulating inner sheath 7. In this case, the outer conductive layer 13 of the energy wires 1 can be dispensed with.

Claims (3)

Fl 4873 -1~ 31.05.89 Protection claims: 1. Cable harness, rubber-insulated power cable constructed from a stranded assembly of three energy cores C1) and in their outer winding spaces a control and/or monitoring core C2 or 3) - the monitoring core (3) consisting of a copper wire conductor (31) with a conductive rubber sheath (32) - and arranged around the stranded assembly C1-3) an inner sheath (7), protective conductor braid (*> and outer sheath (9), characterized in that a monitoring conductor (4) is arranged in the interior of the six cores (cable core) and the remaining interior is filled with an electrically conductive and mechanically high-quality rubber mixture (5), e.g. with a mixture based on EPR (ethylene-propylene rubber) with carbon black added, which has the shape of a cross (conductive rubber cross 5) which separates the energy cores (1) from one another with its three webs (51). 2. Shearing cable according to claim 1, characterized in that the inner sheath (7) is made of an insulating rubber mixture, for example a mixture based on SBR (styrene-butadiene rubber), and that the conductive rubber cross (5) is in contact with the outer conductive layers (13 and 23) of the energy and control wires and the conductive sheath (32) of the monitoring wire (Fig. 1). 3. Shearing cable according to claim 1, characterized in that an additional but conductive inner sheath (6) is arranged between the stranded assembly (1-3) and the insulating inner sheath (7), which is made, for example, of an EPR-based mixture with carbon black additive (Fig. 2).