US2126069A - Electric cable - Google Patents

Description

Aug. 9, 1938. K. WANSKE 2,126,069

ELECTRIC CABLE Filed July 16, 1956 Patented Aug. 9, 1938 ELECTRIC CABLE Kurt Wan'ske, Berlin-Lichtenrade, Germany, assignor to Norddeutsche Kabelwerke Aktiengesellschaft, Berlin-Neukolln, Germany Application July 16, In Germany Claims.

The invention relates to an air space insulated electrical cable.

In the application Ser. No. 89,413 of Otto Cords,

dated July 7, 1936, now Patent No. 2,118,005 5 dated May 17, 1938, the conductor is held concentrically to an external helically wound covering which encloses the insulating air space, by means of threads. The outer covering acts as a supporting structure and consists of a number of helically wound tapes or wires. the present invention is to simplify the construction of this outer covering. Experiments have shown that when a suitable shape is chosen, a single helically wound tape is sufiicient to support the conductor satisfactorily by means of supporting threads or tapes. According to the present invention a tape is used having openings extending in the longitudinal direction. These openings are of such lengths and are placed at such intervals that webs for the supporting threads are formed, which, when the tape is helically wound, are disposed about the coaxial central conductor at an angle of 180 or more in the direction of winding of the tape.

In the one embodiment of the tape forming the external covering slots are provided disposed longitudinally of the tape. In another embodiment these slots are replaced by longitudinal recesses along the edge of the tape. If a tape of 30 this nature is wound into a helix with suitable overlapping, slot-like apertures are obtained, as in the first embodiment referred to.

If the tape forming the covering consists of an insulating substance, a metallic layer forming the return lead is provided on the tape. This return conductor may consist for example, of bands of copper, aluminium or the like, wound with long pitch and forming a closed layer. In some circumstances a lead sheath surrounding the tape a) is sufiicient as a return conductor. If, however, the electrical resistance of the lead sheath is too great, the metallic tapes above referred to may be additionally provided about-the normal covering tape underneath the lead sheath.

The invention is illustrated by way of example in the accompanying drawing:

Fig. 1 shows the complete air space insulated electrical cable;

Fig. 2 is a view of the tape-used in the cable according to Fig. 1.

Fig. 3 shows another construction of the tape.

Fig. 4 shows an air-space insulated electric cable made up of the tape according to Fig. 3.

The tape itself is indicated by B and is provided at regular intervals with slots G. As is The object of a 1936, Serial No. 90.972 March 24, 1936 seen from Fig. '2, the slots extend in the longitudinal direction of the tape. If a tape of this nature is wound to form an open helix, as shown in Fig. 1, any two consecutive webs E between the slots G will be disposed at an angle of at least 180 about the central conductor M, which latter is arranged to be coaxial to the helix.

In the slots G the supporting thread D is laid with the same pitch as the helical winding of the tape B, the thread being slung over the web E between the slots, as shown in Fig. 1.

The webs E lying between the slots correspond to the points of intersection between the tapes and wires according to the aforesaid application of Otto Cords, Ser. No. 89,413. The supporting of the central conductor M according to the present invention is therefore the same as in the said Cords invention. In other words the central conductor is held in position with respect to the outer covering by means of the supporting thread.

The tape according to Figs. 3 and 4 possesses marginal recesses G formed by projections E extending from one edge of the tape at an angle to the longitudinal direction. The projections E are preferably of rectangular shape; This tape is wound into a helix so as to overlap, as shown in Fig. 4. The next convolution of the tape then lies over the projections E which in this case have the same efiect as the webs E in the above described construction. When the tape is wound slot-like apertures are thus formed, as in the constructional form according to Fig. 2, in which the supporting threads D are laid.

What I claim is:

1. An air-space insulated electric cable, comprising a central conductor, an outer covering surrounding the said conductor in spacial disposal thereto and comprising one single helically wound tape having openings disposed longitudinally thereof, and supporting means for the said conductor passed through the openings in the said tape and about the said conductor.

2. An air-space insulated electric cable, comprising a central conductor, an outer covering surrounding the said conductor in spacial disposal thereto and comprising one single helically wound tape having openings disposed longitudinally thereof and spaced apart to form supporting webs, and helically wound supporting means for the said conductor passed through the openings in the said tape and about the said conductor, the said openings in the tape being so spaced that in the wound condition of the tape each two consecutive webs are disposed at an angle of at passed through the openings in the said tape over the said webs and about the said conductor.

4. An air-space insulated electric cable, comprising a central conductor. an outer covering surrounding the said conductor in spacial disposalthereto and comprising one single helically wound tape having marginal recesses, the said tape being wound with overlapping edges so that the said recesses in the finally wound tape constitute in conjunction with the overlapping edge of the next convolution slots and webs intermediate of the said slots, and helically wound supporting means for the said conductor passed through the said slots over the said webs and about the said conductor.

5. An air-space insulated electric cable, comprising a central conductor, an outer covering surrounding the said conductor in spacial disposal thereto and comprising one single helically wound tape having openings disposed longitudinally thereof and spaced apart to form supporting webs, and a thread passed helically through the said openings over the said webs and about the said conductor to hold the said conductor coaxially to the said outer covering.

' KURT WANSKE.

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