Self-supporting cable
The current invention relates to self-supporting cables that often are aerial mounted between cable fixing points ( 800 ) and where the conductors in the cables act as the bearing elements. In this type of cables, slippage between the surfaces of different layers in the cable is undesirable. On the other hand, it must be possible to easily bend the cable, even for larger dimensions. Both these requirements are difficult to meet with the solutions from prior art. The present invention overcomes this by introducing an intermediate layer ( 130 ) between the surfaces ( 112, 121 ) comprising at least on tape ( 511 ) with friction particles ( 512 ) where the friction obtained by the friction particles ( 512 ) is low enough to allow the two surfaces ( 112, 121 ) to slip relatively each other in longitudinal direction enough so that the cable 100 can be bent but prevents the two surfaces ( 112, 121 ) from slipping in response to an inwardly directed radial pressure force (F) at the cable fixing points ( 800 ).
1. A self-supporting cable comprising:
an inner portion comprising at least one conductor;
an outer portion;
an intermediate portion positioned between the outer surface of the inner portion and the inner surface of the outer portion and where the intermediate portion comprises at least one tape made of a non-woven material and comprising friction particles adhered to at least one side of the tape and where the friction between the friction particles and any of the two surfaces is allowing the two surfaces to slip relatively each other in longitudinal direction enough so that the cable can be bent but prevents the two surfaces from slipping in response to an inwardly directed radial pressure force at cable fixing points so that tension forces and the gravitational force acting on the cable between said fixing points can be transmitted into the conductors wherewith the cable becomes self-supporting by virtue of the intrinsic mechanical strength of the conductors.
2. A cable as in claim 1 where the intermediate portion comprises a first tape with friction particles and adhered to one of the two surfaces and where the side with the friction particles is facing the other surface.
3. A cable as in claim 1 where the intermediate portion comprises a first tape with friction particles and adhered to the outer surface of the inner portion and a second tape with friction particles and adhered to the inner surface of the outer portion, and where the sides with the friction particles are facing each other.
4. A cable as in claim 1 where the tape is adhered to the surface by an adhering tape that has become adhesive on both sides in response to heating above a predetermined temperature.
5. A cable as in claim 1 where the intermediate portion comprises a tape having friction particles adhered to both sides of the tape.
6. A cable as in claim 1 where the friction particles consist of sand-blasting sand that has been adhered to the tape by gluing.
7. A cable as in claim 1 where the structure of the intermediate portion is further arranged so that in response to an outwardly directed radial force applied to the outer portion, the outer portion can be easily separated from the inner portion.
8. A cable as in claim 1 where the frictional structure of the intermediate portion is adapted to transform kinetic energy to thermal energy when the two surfaces move relative each other.
9. A cable as in claim 1 being an electrical cable and where the conductors comprise at least one metal wire.
10. A cable as in claim 1 , where the friction particles consist of sand particles adhered by glue to the tape.
11. A cable as in claim 2 , where the friction particles consist of sand particles adhered by glue to the tape.
12. A cable as in claim 3 , where the friction particles consist of sand particles adhered by glue to the tape.
13. A cable as in claim 1 , where the friction particles consist of sand particles adhered by glue to both sides of the tape.