DE2542018B2 - Method of manufacturing a sheathed electrical cable - Google Patents

Description

done at high speed.

Advantageous further developments of the method according to claim 1 are described in more detail in the following claims 2-6.

An embodiment of the invention is shown in the drawing and will be described in more detail below described.

Fig. 1 is a schematic representation of a 1st embodiment;

Fig. 2 is a schematic representation of another embodiment;

Fig. 3 shows the folding back of the side flap of a Plastic tape over the side edge of a metal tape;

Figure 4 is a sectional view taken along line 4-4 of Figure 3;

Figure 5 is a top plan view of the plastic tape when folding back one of the two side flaps and when removing the other side flap;

Figure 6 is a sectional view taken along line 11-11 of Figure 10;

7 shows a further possibility for producing a coated plastic band:

Fi g. Fig. 8 is a sectional view of an electrical cable employing coated plastic tape and having both sides with Side flaps of the plastic tape are provided, the overlapped part of the plastic tape in the Chain-dotted circle is shown in enlarged form;

Fig. 9 is a sectional view of an electrical cable using a coated plastic tape and only one side part with a Side flap of the plastic tape is provided, the overlapped part of the tape in the dash-dotted line Circle is shown in enlarged form.

In the drawings, the same or similar parts are denoted by the same reference numerals.

In Fig. 1, a metal strip 21 is shown, which consists of aluminum, copper or the like and has a sufficient width to cover the core 22 of an electrical cable 23. The metal band 21 has a thickness of 0.1 to 0.2 mm or approximately in this order of magnitude. The metal band 21 is on wound a roll or spool 24 after it has been annealed. Furthermore, a Plastic tape 25 is used because, from an ionomer, ethylene ethyl acrylate copolymer, ethylene methacrylate copolymer, ethylene acrylic acid copolymer, ethylene vinyl acetate copolymer, polyethylene ode, - consists of polyvinyl acetate. It can easily be thermally connected to the metal strip 21, which is preferably made of aluminum. The plastic tape 25 can in turn be a layered tape and consist of one of the plastic materials given in the table below.

First layer of plastic

Second layer of plastic

Ethylene maleic anhydrate
copolymer

Ethylene vinyl acetate copolymer or polyethylene

First layer of plastic

Second layer of plastic

lonomcr

Äthylenvinylacctatmisch polyrnerisat or Äthylcnäthylacrylatmischpoly-

mcnsat

Ethyl acrylic acid mixed polymer

Ethylene vinyl acetate copolymer or polyethylene

The plastic band 25 is slightly wider than the metal band 21 (for example 30%). The thickness of the

ίο the plastic tape is 0.05 mm or less. That

Plastic tape 25 is wound onto a roll 26. The metal strip 21 is unwound from the roll 24

kelt and goes through a braking device 27 to

set the appropriate voltage. There follows one

is roller 28, which is set to a temperature of 110 ° C or has been heated to about 110 ° C.

The metal tape 21 heated in this way and the plastic tape 25 unwound from the roll 26 are sandwiched between a pair of press rollers 29 carried out and compressed. As a result, the plastic strip 25 is thermally connected to the metal strip 21 and is coated in a picture manner Plastic tape 30.

The coated plastic tape 30 is in the from

The direction indicated by arrow A is transported at a speed of, for example, 10 m per minute. During this movement, the outwardly extending tab of the plastic tape is folded over by means of a folding device 31. she consists of a truncated cone roller 32 and a guide plate 33 or a pair of cones! frustum-shaped rollers 32 and a conduit plate 33 to cover the corresponding edge or edges of the metal strip 21.

The folded plastic parts are thermally connected to the opposite side with the side on which the main body of the plastic tape 24 is connected. A cooling device 34, which is arranged below the folding device 31,

to cool the coated plastic belt 30 by emitting a chilled medium, such as air or Wa ^c ser through nozzle 35th

The cooled, coated plastic strip 30 is moved along, for example, by means of a deflection roller 36 of the cable core 22 and moves continuously in the direction indicated by the arrow B. The coated plastic tape 30 is wrapped around the cable core 22 by means of a wrapping or wrapping device or a circulating funnel 37. kelt, the opposite side edge portions of the tape 30 overlapping. Afterward an outer shell 39 is extruded around the coated plastic tape 30, by means of an extrusion> device 38 of known design. The outer shell 3V consists of a weather-resistant and corrosion-resistant plastic material such as polyolefin, polyethylene or polyvinyl chloride, which are easily with the plastic tape 25 or the / wide layer of the plastic tape 25 in one

«Ι can connect two-ply tape.

In Fig. 2 is another form of manufacture an electrical cable 23 according to the invention. There, the Heizwalzc 28 described in Fig. I replaced by a heating furnace 42, which is short

hi is arranged in front of the press rollers 29. to both that Metal band 21 as ai .cn the plastic band 25 on a Heat temperature from 150 ° C to 240 ° C (generally about 200 ° C) at the same time / u. The in Fin. I

illustrated cooling device 34 is by a pair Kühlwalzcn 41 replaced

From Fig. 4 it can be seen that a frustoconical roller 32 is arranged so that its axis is inclined to the surface 21b (hereinafter referred to as "upper surface") at an acute angle la (la should normally be 20 °) is. The distance d between the surface 21fo and the surface of the frustoconical roller 32 is smaller than the thickness of the plastic belt 25. The bottom surface 32a of the frustoconical roller 32 is arranged near the central line of the coated plastic belt 30, while the upper surface 32fr of which is removed from the central line. From the fig. 3 it can be seen that the frustoconical roller 32 is also arranged in such a way that its central axis XX forms an obtuse angle β with the withdrawal direction Λ of the coated strip 30. The obtuse angle β should normally be 120 ".

Due to the different circumferential speeds of the frustoconical roller 32, the folded strip tab 25a of the plastic tape 25 is pulled in the direction of the central line of the coated tape 30. As a result, the folded side tab 25a of the plastic band 25 is thermally firmly connected to the side edge 21a of the metal band 21 without creating a gap between the two. The shape is achieved that no wrinkles are formed on the '.> Beren surface l \ b of Mctallbandes 21st

In FIGS. 5 and 6, the frustoconical roller used for the folding is replaced by a cutting roller 41, the bottom surface 41 of which is very close to the lateral edge 2 \ d of the metal band! 21 is arranged. When the cutting roller 41 is rotated in the direction indicated by the arrow E , the edge 21b of the roller 41 cuts off the unnecessary side flap, such as the side flap ISb of the plastic tape 25. In the case of a coated tape 30 produced, for example, only one side edge 21ü of the metal gang; 21 with the corresponding side flap 25a de; Plastic tape 25 covered.

An outer sheath 39 is shown in FIGS. 8 and 9, made of a weather-resistant and corrosion-resistant plastic material, and is extruded onto the coated tape 30, thus covering the cable core 22. Due to the heat applied by the heat applied to the outer shell 39 and by the properly regulated removal of the shell 39, the side flaps 25a and ISb of the plastic strip 25 are thermally connected to one another, since it lies between the overlapped horizontal side edge 30e and 30 /. The outer shell 39 adheres firmly to the outer lateral vertical edge wall and prevents a gap or gap from being formed between them.

For this purpose 4 sheets of drawings

Claims (6)

Patent claims: l _t Process for the production of a sheathed electrical cable, in which the plastic or metal strip wound on separate supply reels are fed to one another via deflection rollers, the plastic strip is thermally coated on one side with the metal strip, the plastic strip being wider than the metal strip , in which the laterally protruding edges of the plastic tape are bent around the side edges of the metal tape and folded onto the free surface of the metal tape and the resulting side flaps are then also thermally glued to the free surface of the metal tape, the tape coated in this way is applied longitudinally overlapping around a cable core and an outer plastic sheath is extruded around the sheathed cable core, characterized in that when folding one or both side flaps (25e and 2Sb) are first bent, then in the direction of the center line (Y- Y) over the free side of the metal strip (21) in pointed wi nkel to the withdrawal direction (A) , the side flaps are pressed onto the surface of the metal strip (21) by means of one or more frustoconical rollers (32), the axes of which are arranged obliquely to the perpendicular to the withdrawal direction (A), and that the coated in this way Plastic belt (30) cooled (34. 35) and is fed to an inlet funnel (37) via pulleys (36). 2. The method according to Ansj;: / uch 1, characterized in that only one of the two side flaps (25a or 256) of the plastic band (25) is folded over the corresponding side edge (21a or 2Id) of the metal strip (21) and the other side flap (25 *) or (25e) cut off by means of a rotating cutting roller (41) will. 3. The method according to any one of claims 1 or 2, characterized in that either the metal strip (21) alkine or the metal strip (21) un <J the plastic band (25) are heated prior to being pressed onto one another. 4. The method according to any one of claims 1 to 3, characterized in that the plastic tape (25) made of Ethylenäthylaerylatmischpolymerisat, Ethylenmethylacrylatmischpolymerisat, Ethylenacrylsäuremischpolymerisat, Äthlenvinylacetatmischpolymerisat, polyethylene or polyvinyl acetate. 5. The method according to any one of claims 1 to 4, characterized in that the plastic strip (25) in turn is made up of two layers is, wherein the first layer consists of the substances specified in claim 4 and the second of Ethylenvinylacctatmischpolymcrisat or Äthylcnälhylacrylatmischpolymcrisat. 6. The method according to any one of claims 1 to 5, characterized in that the plastic strip (25) consists of a first layer of ethylenacrylic acid copolymer or ethylcnmalcic acid canhydrate and a second layer of ethylene vinyl acetate copolymer or polyethylene. The invention relates to a method for producing a sheathed electrical cable in which the plastic or metal tape wound onto separate supply reels via deflection tubes are fed to one another, the plastic strip is thermally coated on one side with the metal strip, the plastic strip being wider than the metal band, in which the laterally protruding edges of the plastic band around the side edges of the ίο the metal band bent over and onto the free surface of the metal tape and the resulting side flaps are then also thermally glued to the free surface of the metal tape, the so coated tape overlapping lengthways around a cable soul applied and an outer plastic cover around it Here the sheathed cable core is extruded. The conventional processes for the production of laminated or coated sheathed electrical cables consist of the following process stages fen: First, a thin band or a thin layer of plastic material, such as Polyethylene or polyvinylchloride bonded with glue or thermally with an aluminum tape or a thin layer of aluminum to form a laminate or to form a laminate. The laminated tape is applied along a cable core in such a way that the lateral edges overlap one another. the Overlap seams are connected by means of an adhesive such as a copolymer den and finally an outer shell made from a wet Solid and resistant plastic material applied. In the known electrical cables produced by the method described above come however, lap seams in direct contact with the outer shell. Because the plastic of this outer In general, the casing cannot be connected to the aluminum, a gap or a gap is formed Space that extends along the cable. With aging and repeated stretching, this becomes Effect even stronger. Cracks form and extend from the space to the surface of the cable jacket exposed to the atmosphere. This increases the weather resistance and durability of the cable against moisture is greatly reduced. From US-PS 3902938 it is known to cover a metal band with a plastic band mitteis Foimungsrolle so that the side so edge parts of the metal tape are covered with the plastic tape. However, the plastic tape will do this folded around the metal strip in one go in such a way that an overlapping seam of the plastic strip is formed only on one longitudinal side of the metal strip. The invention is based on the object of developing a method for producing a sheathed electrical cable that is resistant to major temperature fluctuations and, if possible, is waterproof. M) This task is carried out by the in the characterizing Part of claim 1 specified process steps solved. Through the action of heat or heat, a firm and tight bond with the other side and the it created the edge part or the edge part of the metal band. The withdrawal of the plastic tape, the folding and thus the entire production of the cable can