FR2692073A1 - Flexible electric cable especially for the power supply of shearers. - Google Patents

Abstract

a) Flexible electric cable, in particular for supplying power to shearers. b) Cable characterized in that the inner sheath (9) is conductive and the other strands (3) are provided with a cabling of copper cords (conductors, protectors) and a conductive sheath applied to this braid and in this that in a known manner, between the energy conductor and the insulating sheath (12) of the energy conducting strands (2) there is as separator a fleece (12a) connected by a connection by the material to the material of the insulating sheath (12) and / or the material of the inner sheath (9) is in a polymerized elastomer and having a residual plasticity allowing it to deform, the braid (10) being able to penetrate into the inner sheath (9) under the effect of crushing or impact stresses.

Description

"Flexible electrical cable especially for the power supply of

  The invention relates to an electric cable

  flexible with signaling elements of endoma-

  in conductive structures before a

  short circuit for the machine power supply

  not mobile in particular for the power supply of shearers, this cable being essentially composed of a

  wired set of three conductor strands

  energy in fine copper wires and whose outer winding spaces receive other strands, a

  conductive rubber cross filling the space between the energy-conducting strands and a conductor in the center of the cross, an inner sheath surrounding the wired assembly, which sheath is itself surrounded by a braid and a sheath exterior.

  German Offenlegungsschrift No. 39 34 718 A1 discloses a shear braid with increased electrical safety against crushing and shock stresses. This braid consists of a cable having essentially three conductor wires of The latter are insulated and are surrounded by a conductive braid provided around the insulation and comprising control and / or monitoring conductors in

  external winding volumes as well as a

  monitoring conductor provided at the center of the winding space in a conductive rubber cross

  which is planned and separates the strands providing the energy

  The conductive envelopes of the control wires

  or / and monitoring are on the sheaths of i-

  respective strands of neighboring power transmission strands Transmission strands and

  Auxiliary strands are wired and this cable combination

  is coated with an inner casing formed of the conductive rubber mixture and a mixture of insulating rubber attached to the preceding mixture, a concentric protective conductor formed of a braid of copper cord and steel and a

outer sheath.

  In the case of deformations caused by crushing or shock stresses of the cable with

  as a consequence damage to the structures de-

  written, in particular insulating sheaths of the strands driving the energy in the core of the cable, there must firstly be an electrical contact between a strand transmitting the energy and the conductor of the cable.

  associated monitoring in its relevant volume.

  winding or conductive sheaths

  auxiliary strands before a short

  phase circuit between the strands of energy The signal

  resulting from this electrical contact transmitted to a

  monitoring system cuts off the network.

  In this solution, the deformation of the con-

  conductor must arrive until damage to the core of the cable, that is to say causing a bursting of the insulating sheath of at least one strand driving the energy in the vicinity of the supervisor conductor or a

  auxiliary wire before there is a transmission of

  This means that the signaling and short-circuiting situations for which the sheaths

  insulators of at least two transmission strands of

  The energy must have burst, if necessary, be sufficiently close together in time so that there is nevertheless a short circuit. It is moreover known to provide between an energy conductor formed of fine copper wires and

  its insulating sheath, a separator avoiding the penetration

  insulation material in the energy conductor.

  which improves the sliding behavior It is also known to use as separator a

  nonwoven (DE-OS 28 18 492, DE-OS 31 51 232).

  The present invention aims to achieve

  a flexible electrical cable corresponding to the defined type

  nor above in particular for the elec-

  shredder so that the risk of damaging the conductive structures by crushing or shock stresses is reduced and

security is increased.

  For this purpose the invention relates to a cable

  flexible electrical cable characterized in that the inner sheath

  is conductive and the other strands are equipped

  Copper cord cabling (conductive,

  sensors) and in a known manner, between the energy conductor and the insulating sheath of the energy-conducting strands, a fleece connected by a connection by the material of

  the insulating sheath and / or the material of the sheath

  is made of a polymerized elastomer and having a residual plasticity allowing it to deform, the braid being able to penetrate into the inner sheath

  under the effect of crushing or shock stresses.

  In the cable structure according to the invention

  a braid around an inner envelope

  conductor surrounding the wired assembly formed by the power transmission and other

  strands, essentially ensures the reinforcement and resistance

  cable traction and the driver of the

  protection is provided as an outer cable formed of a

  copper cord on the other strands.

  Since an energy conductor formed of

  thin copper wire and its insulating sheath, to improve

  improve the energy driver's slip in the

  insulation and to prevent the penetration of the

  age of the sheath in the energy conductor, comprises

  as a means of separating a nonwoven, connected to the

  In this case, the insulating sheaths of the solution according to the invention were found to burst at the outer edge of the assembly. wired before they burst into the heart and generate a short circuit situation This burst in the area adjacent to the conductive inner envelope

  leads to an electrical contact between the

  energy producers and the inner envelope (

  signaling) which transmits by this conductor and the conductive sheaths control and / or monitoring or other conductive layers, a

  signal for the surveillance system This one

  git and cut off the network Because the insulating sheaths

  burst first at the outer edge of the cable assembly before bursting into the heart (and not

  conversely) the situation of short circuit, that is,

  say when the insulating sheaths burst in the heart and allow electrical contact between the

  strands carrying energy, is so

  significant downstream of the signaling situation.

  This greatly reduces the risk of a short

circuit.

  The arrangement of an inner conductive sheath

  polymer formed elastomer having a residual plasticity between the wired assembly and the braid allows the braid to

  or shock to penetrate the envelope

  the braid does not deform by increasing its periphery under the effect of crushing and shock stresses but enters the envelope

  inside and the pressure acting on the cable assembly

  wheat constituting the cable escapes and is not

  not transmitted in all its amplitude to the whole

  cable which delays the bursting of the insulated sheaths

  When the braid continues to be pressed

  insulation sleeve (s), this apparently produces

  In this case, the introduction of a deformable conductive inner sheath also serves to increase the interval of

  between the signaling situation and the situation

  short circuit and acts in alternation with the structure of the invention insulating sheaths

  strands of energy nevertheless in common with this characteristic.

  to increase security Because the

  braid serves as a frame and does not have to

  particular electrical power, it may be advantageous

to make it out of steel wire.

  For excellent mutual penetration

  of the inner envelope and the braid it is

  to choose a coating of the inner envelope

  The present invention will be described hereinafter with the aid of an exemplary embodiment shown in the single figure which is a cross-section of a flexible electrical cable for the power supply

shearers.

  The cable is a stranded cable formed of three energy-conducting strands 2, placed on a resilient conductive rubber core 1, formed of a mixture based on ethylene-propylene-rubber (EPR) being separated by the wings. from this cross,

  the outer intervals of the winding are occu-

  driven by control strands 3; these are surrounded by rubber insulation (based on

  EPR rubber) and a tinned copper cord (

  protective conductor 1/3) then surrounded by a ribbon

  conductor 6 In the center of the rubber cross

  conductor 1 is a conductor 7; jute cords 8 are provided as well as an inner casing 9 made of ethylene-propylene rubber (EPR) with addition of carbon black with residual plasticity surround the wired assembly The whole is surrounded by a braid of steel wires 10 (2 x 20 x 3 x steel cord (7 x 0.025) ZN) and an outer sheath 11 made of polychloroprene. The strands driving the energy 2 are strands of tinned copper wires surrounded by a nonwoven of polyester of an extruded structure having a thickness of about 0.25 mm and then of an insulating rubber sheath 12b extruded onto the nonwoven

  polyethylene 12 a; then we vulcanize and so a

  EPR-based rubber blend penetrates

  in the structure making a connection of

  be the non-woven polyester fleece 12a and the sheath

rubber 12b which envelops it.

  When the outer casing 11 of the cable is urged by crushing or impact stresses, the steel wire braid 10 is pressed against the conductive inner sheath 9 The stress-induced sectional variation which is related to

  an increase in the periphery of the inner envelope

  9; and because of the deformability of this

  9, the steel wire braid 10, which substantially retains its peripheral length, penetrates into the inner casing 9, crosses it and finally applies against one or more insulation ducts 12 This operation reduces the pressure exerted on the heart of the whole cable so much so that

  this firstly delays the bursting of the insulating sheaths

  12 in this part (if applicable also

  situations of short circuit) and leads everything from

  edge to a burst of the insulating sheaths 12 in the

  zone where the braid of steel wires arrives.

  insulation ducts 12 in turn leads to an electrical contact of the energy-conducting strands 2 and the steel wire braid 10 with the material

  conductor of the inner sheath 9 (situation of

  SIGNS AND SIGNALS); there is then emission of a signal which cuts the network This signal situation is thus very upstream of the situation of short-circuit

  which considerably reduces the risk of short-

circuit.

Claims (2)

R E V E N D I C A T IO N S   ) Flexible electric cable especially for the power supply of shearers, this cable being essentially composed of a wired assembly formed of three strands of copper wire   and whose outside winding spaces   other strands, a rubber cross   conductor filling the space between the conductive strands   energy providers and a driver in the center of the   cross, an inner sheath surrounding the cable assembly   wheat, this sheath being itself surrounded by a braid and an outer sheath, cable characterized in that the inner sheath (9) is conductive and the other strands (3) are provided with a copper cord cabling (conductors, guards) and a conductive sheath applied on this braid and in that   known, between the energy conductor and the insulated sheath   lant (12) of the conductive strands of energy (2)   separator a fleece (12 a) connected by a link   by the material to the material of the insulating sheath (12) and / or the material of the inner sheath (9) is made of a polymerized elastomer and having a residual plasticity allowing it to deform, the braid (10) being able to penetrate into the inner sheath (9)   under the effect of crushing or shock stresses.   2) Flexible electrical cable according to the   1, characterized in that the braid (10) is formed of steel wires.   ) Flexible electrical cable according to the   1 or 2, characterized in that the braid (10) does not cover more than 60% of the inner sheath (9).   ) Flexible electrical cable according to the   1, characterized in that the material of the   inner sheath (9) is ethylene rubber   polypropylene (EPR) with addition of lampblack.