Method of twisting elements to form an electrical cable having a twist whose direction alternates from section to section

Claim 3

The invention according to claim 1, wherein the magnitude of the torsion acting behind said first twisting point is constant.

Claim 4

The invention according to claim 1, wherein the torsions acting at said first and second twistinG points are changed simultaneously at intervals corresponding to the travel time of a length element between said first and second twisting points.

Claim 5

The invention according to claim 3, wherein said torsions are changed proportionally.

Claim 6

Apparatus for twisting cable elements to form a cable unit having a twist direction which changes from section to section comprising: a. means acting as a first twisting point at which a plurality of elements may be formed into a strand, from which the cable units are to be formed; b. a first twisting head immediately behind said first twisting point to grip the strand perpendicular to its axis; c. a second twisting point; d. a second twisting head immediately before said second twisting point adapted to grip the strand in a manner similar to said first twisting head; e. means to hold the strand stretched between said first and second twisting points; and f. means to rotate said first and second twisting heads so that both rotate in the same direction but with a speed ratio such that ratio of the speed of the first twisting head to that of the second is always greater than the ratio of the distance between the first twisting point and the first twisting head to the distance between the first twisting point and the second twisting head, and to change the relative rotational speeds of said first and second twisting heads at intervals corresponding at most to three times the travel time of a length element of the strand between said first and second twisting points.

Claim 7

Apparatus for twisting cable elements to form a cable unit having a twist direction which changes from section to section comprising: a. means acting as a first twisting point at which a plurality of elements may be formed into a strand, from which the cable units are to be formed; b. a first twisting head immediately behind said first twisting point to grip the strand perpendicular to its axis; c. a second twisting point; d. a second twisting head immediately before said second twisting point adapted to grip the strand in a manner similar to said first twisting head; e. means to hold the strand stretched between said first and second twisting points; and f. means to rotate said first and second twisting heads so that both rotate in the same direction but with a speed ratio such that ratio of the speed of the first twisting head to that of the second is always greater than the ratio of the distance between the first twisting point and the first twisting head to the distance between the first twisting point and the second twisting head, and to change the relative rotational speeds of said first and second twisting heads at intervals corresponding at most to three times the travel time of a length element of the strand between said first and second twisting points.

Claim 8

The invention according to claim 5, wherein said first twisting head is rotated at a constant speed.

Claim 9

The invention according to claim 5, wherein said means to change simultaneously changes the speed of both twisting heads at intervals corresponding to the travel time of a length element between said first and second twisting points.

Claim 10

The invention according to claim 7, wherein said means to rotate comprises a single source of drive power coupled to said first and second twisting heads through means having different transmission ratios.

Claim 11

The invention according to claim 5, wherein each of said first and second twisting heads comprise: a. at least one pair of rollers; b. means supporting said rollers on parallel axes disposed opposite each other such that a strand may be gripped between said rollers and wherein each roller includes; c. a groove running about the circumference of the roller over the major portion of the roller running surface width; and d. a friction lining made of an elastic material embedded in said groove and bonded to the bottom thereof in a manner such that a hollow space is formed between the bottom of the groove and the portion of said lining forming the roller running surface.

Claim 12

The invention according to claim 9, wherein said friction lining has a U-shape with the legs of the U bonded to the bottom of said groove and with the base of the U forming the running surface.