DK144076B

DK144076B - ELECTRICAL CABLE

Info

Publication number: DK144076B
Application number: DK178676AA
Authority: DK
Inventors: J G Moberg
Original assignee: Ericsson Telefon Ab L M
Priority date: 1975-04-22
Filing date: 1976-04-21
Publication date: 1981-11-30
Also published as: DK144076C; FI761066A; BR7602345A; NO761350L; FI60788C; DK178676A; NO137569C; NO137569B; DD123904A5; FI60788B; DE2616167A1

Description

o χ 144076o χ 144076

Opfindelsen angår et elektrisk kabel af den i krav l's indledning angivne art.The invention relates to an electrical cable of the kind specified in the preamble of claim 1.

Der anvendes i dag i stor udstrækning kablede, isolerede ledere i stedet for uisolerede ledere som luftled-5 ninger for lavere spændinger. Disse kabler har mange fordele, såsom enklere montering og færre afbrydelser og kortslutninger på grund af omblæste træer og lignende. Håndteringen af kablet ved udlægning er rationaliseret i høj grad ved, at kablet leveres i lange stykker, der vikles i en spole uden kabeltromle. Ved udlægningen lægges spolen på jorden, og den indre ende i spolen trækkes ganske enkelt ud. Dette medfører, at kablingen enten bliver løsere eller fastere afhængigt af kablingsretningen i forhold til spolens viklingsretning.Today, wired, insulated conductors are used to a large extent instead of uninsulated conductors such as overhead lines for lower voltages. These cables have many advantages, such as simpler mounting and fewer interruptions and short circuits due to blown trees and the like. The handling of the cable during laying is greatly rationalized by the cable being delivered in long pieces wound in a coil without cable drum. When laying, the coil is laid on the ground and the inner end of the coil is simply pulled out. This causes the cabling to either become looser or firmer depending on the wiring direction relative to the coil winding direction.

Specielt når kablingen bliver løsere, har det vist sig, at der 15 er risiko for, at kablets dele forskydes i længderetningen.Especially when the cabling becomes looser, it has been found that there is a risk of the cable parts being displaced longitudinally.

Hvis kablet hænges op i masterne ved hjælp af organer, der fastklemmer alle dele, er der risiko for, at belastningen bliver ujævnt fordelt med risiko for brud.If the cable is suspended in the masts by means of clamping all parts, there is a risk that the load will be unevenly distributed with the risk of breakage.

Det er endvidere almindeligt at mærke kablets dele 20 for at kunne holde rede på ledningens faser. Man udfører passende denne mærkning som forskellige antal langsgående ribber, således at lederne kan identificeres såvel visuelt som berøringsmæssigt. Ved de hidtil kendte kabler har det vist sig, at markeringen ofte kommer til at ligge indad i det udlagte ka-25 bel, hvilket giver problemer ved identificeringen.Furthermore, it is common to label the parts of the cable 20 in order to keep track of the wiring phases. Suitably, this marking is performed as different numbers of longitudinal ribs, so that the conductors can be identified visually as well as touch-wise. With the previously known cables, it has been found that the marking will often lie inward in the laid cable, which causes problems in identification.

Pra dansk patentskrift nr. 128.964 kendes et kabel af den i krav l's indledning angivne art. I dette kabel er mellemstykkerne, der forbinder kabelparterne med hinanden, forholdsvis brede og tykke, idet de er bestemt til at udfylde 30 mellemrummet mellem parterne på en sådan måde, at det færdige kabel er cirkelrundt i tværsnit. Mellemstykker med en sådan udformning kræver en stor materialemængde, af samme størrelsesorden som den mængde, der anvendes til isolation i de enkelte kabelparter, og forøger stivheden i betydelig grad. End-35 videre kan en krympning af dette kabels mellemstykker bevirke, at der optræder en høj belastningskoncentration i overgangen o 2 146076 mellem mellemstykkerne og kabelparterne, nemlig der, hvor mellemstykkerne er tyndest. I øvrigt behøves der til det kabel, som opfindelsen angår, ikke noget cirkelrundt tværsnit, idet kablet som ovenfor antydet er bestemt til ophæng-ning på f.eks. master, og derfor ikke kræver den samme beskyttelse som f.eks. et jord- eller installationskabel.In Danish patent specification No. 128,964, a cable of the kind specified in the preamble of claim 1 is known. In this cable, the spacers connecting the cable parts to each other are relatively wide and thick in that they are intended to fill the space between the parties in such a way that the finished cable is circular in cross section. Spacers of such design require a large amount of material, of the same order of magnitude as the amount used for insulation in the individual cable parts, and significantly increase the stiffness. Further, a shrinkage of this cable's spacers can cause a high concentration of stress to occur in the transition between the spacers and the cable portions, namely where the spacers are thinnest. In addition, no circular cross-section is required for the cable to which the invention relates, the cable as indicated above being intended for hanging on e.g. masts, and therefore do not require the same protection as e.g. an earth or installation cable.

Kablet ifølge opfindelsen er ejendommeligt ved den i krav l's kendetegnende del angivne udformning. Ved at udforme mellemstykkerne som smalle tunger formindskes deres ^ vægt, stivhed og materialebehov væsentligt, samtidigt som de problemer, der kunne opstå ved en eventuel krympning af tungerne, formindskes i betydelig grad. Ved den angivne anbringelse af tungerne opnås desuden, at markeringen i det færdige kabel altid bliver synlig, så at de enkelte kabel-parter kan identificeres på et hvilket som helst sted på kablet uden at åbne dette. Da tungerne således kun udøver, hvad der kunne kaldes en styrefunktion, kan de udformes med en så lille godstykkelse, at de lige netop ikke revner ved den normale belastning under kablets udlægning, og med en så lille 2Q godstykkelse vil deres bidrag til kablets stivhed være forholdsvis lille.The cable according to the invention is peculiar to the design according to the characterizing part of claim 1. By designing the spacers as narrow tongues, their weight, stiffness and material requirements are significantly reduced, while the problems that might arise from possible shrinkage of the tongues are greatly reduced. Furthermore, the specified positioning of the tongs ensures that the marking in the finished cable is always visible, so that the individual cable parts can be identified at any place on the cable without opening it. Thus, since the tongues only exert what could be called a control function, they can be designed with such a small thickness that they just do not crack at the normal load during the laying of the cable, and with such a small 2Q thickness, their contribution to the rigidity of the cable will be relatively small.

Opfindelsen forklares i det følgende nærmere under henvisning til tegningen, på hvilken fig. 1 viser et snit gennem kabelparterne efter isolering, men før kabling, og 25 fig. 2 samme kabel efter kablingen.The invention will now be explained in more detail with reference to the drawing, in which: FIG. 1 shows a section through the cable parts after insulation but before wiring; and FIG. 2 the same cable after the cabling.

I fig. 1 betegner 11, 12, 13 og 14 fire kabelparter i et kabel. Hver part består af en leder 15 og en isolerende kappe 16. I forbindelse med at den isolerende kappe sprøjtes ^ rundt om lederne, forbindes disse indbyrdes ved hjælp af tunger 17, 18, 19 af samme materiale som kappen 16. På kappen udformes endvidere ribber 20, der anvendes til identifisering af lederne. I det viste eksempel er lederne 12, 13 og 14 forsynet med henholdsvis 2, 3 og 4 sådanne ribber 20.In FIG. 1, 11, 12, 13 and 14 represent four cable parts in a cable. Each part consists of a conductor 15 and an insulating sheath 16. In connection with the insulating sheath being sprayed around the conductors, these are interconnected by means of tongues 17, 18, 19 of the same material as the sheath 16. On the sheath, further ribs are formed. 20 used to identify the leaders. In the example shown, the conductors 12, 13 and 14 are provided with 2, 3 and 4 respectively such ribs 20.

Tungerne 17, 18 og 19 har en sådan placering og en sådan bredde, at markeringerne 20 på samtlige kabelparter vil rettes udad samtidig med at tungerne 17-19 ikke udsættes for 144076 0 3 unødig strækning. Hvis kabelparterne fremstilles i form af et bånd som i figur 1, kan man tænke sig at en radius gennem en dels centrum til tungens fodpunkt danner en vinkel α med et plan gennem delenes midtpunkter. Vinklen α kan da ligge mellem 5 0° og 20°. Ved en vinkel på 20° kommer parterne i det plane bånd til at ligge nær hinanden. Ved vinklen 0° vil tungerne 17-19 have en betydelig bredde, ca. 0,3 gange kabeldiameteren.The tongues 17, 18 and 19 have such a location and width that the markings 20 on all cable parts will be directed outwards while the tongues 17-19 are not subjected to unnecessary stretching. If the cable portions are made in the form of a ribbon as in Figure 1, it is conceivable that a radius through the center of a part to the base of the tongue forms an angle α with a plane through the midpoints of the parts. The angle α can then be between 50 ° and 20 °. At an angle of 20 °, the parties in the plane band will be close to each other. At the angle 0 °, the tongues 17-19 will have a considerable width, approx. 0.3 times the cable diameter.

Der er dog betydelig risiko for at en så bred tunge krymper ved afkølingen, idet der ved denne opstår spænding i tungen. En |_q smallere tunge er derfor at foretrække.However, there is a significant risk of such a wide tongue shrinking upon cooling, as this causes tension in the tongue. A | _q narrower tongue is therefore preferred.

Et almindeligt udtryk for tungens optimale bredde b er b = d (1-cos (-^ 2-- hvor d er ledningens diameter, β er hjørnevinklen i den 15 mangekant, hvis hjørner dannes af parternes midtpunkter efter kablingen, og α jer angivet ovenfor, α antager værdier mellem + ^ 2"" °9 “ 1 ~2 · Udtrykket cos ( } 1 ^" ~ o) skal dog være større end cos a, for at det skal være muligt at fremstille de sammenbundne kabelparter i form af et plant bånd.A common term for the optimum width b of the tongue is b = d (1-cos (- ^ 2 - where d is the diameter of the wire, β is the corner angle at the 15 polygon whose corners are formed by the midpoints of the parties after the cabling, and α is given above). , α assumes values between + ^ 2 "" ° 9 “1 ~ 2 · However, the term cos (} 1 ^" ~ o) must be greater than cos a in order to make the interconnected cable portions in the form of a flat ribbon.

20 „20 "

Ved sammenkabling af parterne i bandet i figur 1 kommer samtlige markeringer 20 til at ligge udad på kablet, og risikoen for fejlidentificering er minimal. Tungerne forhindrer desuden at lederne forskydes i forhold til hinanden ved udlægningen, hvorfor der opnås en jævnere fordeling af belast-25 ningen ved ophængningen. Som en sekundær virkning hindrer tungerne snavs og vand eller is i at trænge ind i rummet mellem parterne og øge belastningen.When interconnecting the parties in the band in Figure 1, all markings 20 will be outward on the cable and the risk of misidentification is minimal. In addition, the tongues prevent the conductors from being displaced relative to each other during the laying, which is why an even distribution of the load is obtained at the suspension. As a secondary effect, the tongues prevent dirt and water or ice from entering the space between the parties and increase the load.

Det har vist sig, at kablet i visse tilfælde kan blive så stift, at håndteringen vanskeliggøres. Dette undgås 30 ved at tungerne 17, 18, 19 med visse mellemrum forsynes med åbninger. Åbningerne kan have form af slidser, der passende skæres op med en kniv, der periodisk føres imod tungen. Det er også muligt ved hjælp af passende værktøj at udstanse aflange huller. Hvor stor en del af tungen, der skal gennembrydes, afhænger af flere faktorer, såsom tungens tykkelse, men slidser, der optager 25-75% af tungens længde, har vist sig at 35 o 4 146076 give et håndterligt kabel. Foruden at kablet bliver lettere at håndtere, opnår man yderligere den fordel, at slidserne kan tjene som rivningsanvisninger, når kabelparterne skal adskilles, f.eks. ved montering i ophængningsorganer. Man kan ganske 5 enkelt stikke en finger ind i slidsen og rive tungen op uden brug af noget værktøj.It has been found that in some cases the cable can become so rigid that handling becomes difficult. This is avoided by the opening of the tongues 17, 18, 19 at certain intervals. The openings may take the form of slits which are appropriately cut with a knife that is periodically inserted against the tongue. It is also possible to cut elongated holes with the aid of suitable tools. How much of the tongue to pierce depends on several factors, such as the thickness of the tongue, but slits occupying 25-75% of the length of the tongue have been found to provide a manageable cable. In addition to making the cable easier to handle, the advantage is further that the slots can serve as demolition instructions when separating the cable parts, e.g. when mounted in suspension means. You can simply put a finger into the slot and tear your tongue up without the use of any tools.