Rotary transmission device for a plurality of cables between two restrictedly rotatable structures

Claim 1

A rotary transmission device for a plurality of cables between two coaxial, rotatable structures comprising: two spaced apart plates, between which at least one support band is arranged said support band being laid perpendicular to the plates along a spiral, thereby forming spiral windings, the support band having a first end fastened at the one structure and a second end fastened at the other structure, a plurality of electrical cables laid along the outer side of said support band, a plurality of fastening devices distributed along the support band in spaced apart relation for fastening said electrical cables to said support band, means for slidably mounting said support band with respect to said plate, wherein one of said structures is provided with a cylindrical housing comprising a cylindrical wall, a bottom and a cover, the bottom and the cover being formed by said plates, said other structure comprising a substantially cylindrical hollow hub concentrically extending into said housing, and wherein the support band is secured at its ends to the wall of the housing and at the hollow hub, respectively, said ends extending tangentially to the wall and the hub, at least one axial passage slit for the cables being formed in said hub, wherein the cables are laid in a wavelike course along the support band, and wherein said fastening devices fixedly fasten said cables to the support band at every second apex of the wavelike course and retain said cables at every other apex of the wavelike course, said fastening devices providing radial and axial clearances with respect to the spiral at said every other apex.