Textiles: spinning – twisting – and twining – Apparatus and processes – Unitary multiple twist devices
Patent
1996-06-17
1998-03-17
Stryjewski, William
Textiles: spinning, twisting, and twining
Apparatus and processes
Unitary multiple twist devices
57 5854, 57 5855, 57 5863, 57 5883, 57 67, 57293, 57294, D01H 110, D01H 786
Patent
active
057273758
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The subject of the invention is a method and an apparatus for stranding elongate elements, such as wires and conductors of electrical cables, into a strand of a reverse twist, i.e. alternate left and right one, called SZ-type strand.
There are some well-known and widely applied various methods of stranding elements into strands. Generally, the methods can be divided into two groups: the unidirectional twisting (either left or right) and the alternate reverse twisting in, both directions (left and right), or hence called SZ twisting.
One of the known methods of unidirectional twisting is the method applied in single twist bunchers. A bundle of parallel elements enters a rotating flyer, along its axis of rotation situated horizontally. The task of the flyer is to twist the bundle and wind it up on a spool. The flyer has a shape of the letter L and is so arranged that its axis of rotation goes close to the end of its one segment and is parallel to another segment. Next, the bundle is guided along the flyer and after leaving the flyer is wound on the take-up spool, which rotates around the same axis as the flyer and in the same direction but with different speed. The twist is produced at the entrance to the rotating flyer and depends on the difference of rotational speeds of the flyer and the spool and on the diameter of a core on which the bundle is wound up.
The known methods of stranding elements with the alternate reverse twist, i.e. SZ-type, require application of long accumulators (stores). The accumulators of various constructions are placed between two holeplates: a fixed dividing holeplate at one end of a machine, and a periodically oscillating twisting holeplate, rotating alternately in both directions, at the other end downstream. In another type of SZ stranders, the accumulator is placed between twisters, rotating alternately with various speeds. The periodically alternate strand is produced due to periodical and sudden changes of rotational speeds of the plates or twisters.
An output of the mentioned above methods of the reverse stranding is limited by masses and diameters of the rotating plates and twisters, and particularly, by rotational inertia occurring when the direction or value of the rotational speed is suddenly changed. Consumption of energy, necessary to accelerate and brake the masses alternatively, is also relatively big. Long accumulators require large areas in workshops. An example of a method of continuous SZ twisting in which the direction of rotating the flyer and an intermediate storage drum are reversed with the disadvantages outlined above is described in JP-A-53041533. In this arrangement the twist generated is dependent on the diameter of the drum, so a drum charge would be necessary if a twist change were required.
SUMMARY OF THE INVENTION
The method of stranding elongated elements into the strand of reverse twists according to the invention, is based on the idea, that a bundle of elements is inserted into the winding flyer, producing the first twist in the bundle and winding the bundle on a drum which acts as an accumulator. Simultaneously, the bundle is unwound from the drum by means of an unwinding flyer, producing the second twist in the bundle. Next, the bundle is pulled out of the unwinding flyer. Both flyers and the drum have a common axis of rotation and rotate in the same direction. A repeating period of stranding the bundle of elements consists of at least two successive phases of twisting. A length of the bundle twisted in one phase by the winding flyer is next twisted in another phase by the unwinding flyer. The strand of the bundle is an algebraic sum of successive twists produced in particular phases of twisting.
In an advantageous solution, the bundle is twisted in two phases and during each of them rotations of the flyers and of the drum are constant. During the same phase of twisting the same rotational speed of the winding and unwinding flyers are applied and in both phases the same differences of rotational speeds between e
REFERENCES:
Week 7821, Derwent Publications Ltd., London, GB; AN 78-37690A & JP, A, 53 041 533 (Fujikura Cable Works) 15 Apr. 1978.
Patent Abstracts of Japan, vol. 17, No. 450 (E-1416) 18 Aug. 1993, & JP,A,51 001 728 (Yazaki), 23 Apr. 1993.
Stryjewski William
The Northampton Machinery Company Limited
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