Textiles: spinning – twisting – and twining – Apparatus and processes – False twist device
Patent
1996-10-18
1998-06-30
Stodola, Daniel P.
Textiles: spinning, twisting, and twining
Apparatus and processes
False twist device
D01H 111
Patent
active
057716757
DESCRIPTION:
BRIEF SUMMARY
The invention concerns a process for alternately giving a yarn an "S" twist or a "Z" twist. The invention further concerns a device for false-twist texturing by means of a plurality of twisters driven in the same direction to exert a common effect on a yarn passing through them, which device can also be adapted to perform the aforesaid process.
The problem of changing a friction false-twist system from the "S"- to the "Z"-twist direction has been debated for many years and discussed in many published works, but no solutions that are easy to operate satisfactorily, uncomplicated in design and inexpensive to manufacture have become known. Much of the literature proceeds on the assumption that the friction disks have to assume a set position in the system. To accomplish this, friction disks are removed from the particular bearing and reinstalled in another position. During this operation, care must be taken to ensure that the disks in these mutually overlapping sets of friction disks are still in a set order even after the twist direction has been changed from "S" to "Z".
This problem was addressed in German Patent Application (Examined) 23 10 802, according to which the yarn follows a helical path as it passes from one friction surface to the next. Care must be taken in this context to ensure that the direction of this helical path, seen in the direction of travel of the yarn, is the same as the direction of movement of the friction disks or friction surfaces when they are in contact with the yarn. To produce an "S" twist, the direction of the helical path and the direction of travel of the friction surfaces must be the opposite of those needed to produce a "Z" twist. To achieve this, the aforesaid reference proposes, as a first approach, to reverse the direction of rotation of the friction disks and to convey one of the three sets of friction disks out of its position on the one side of the other two sets of friction disks into a corresponding position on the other side of the other two sets of friction disks, with the sequence in which the yarn comes into contact with the friction disks remaining the same. Alternatively, the aforesaid reference proposes to provide two separate groups of sets of friction disks, each in the form of a "plug-in," i.e., all the necessary disks are creeled on and fastened to a sleeve. To effect the changeover between "S" and "Z" twist, all the sets of friction disks must, of course, be lifted out of a receptacle simultaneously, since otherwise they would not be released from their overlap. Toothed belts and the like also must be removed before the changeover, so that it is impossible to effect a changeover on the machine, resulting in very long downtimes and consequent loss of production.
In a known false-twist device of the same species (German Patent Application 29 43 279 C2), changeover capability is obtained in that the right and/or left sets of disks can be swung out on two pivots to release the overlap, so that all three sets of disks are free. Individual disks, and especially the two sets of friction disks that have been swung out, can then be transposed. This realization does make it necessary first to remove the entire unit from the machine as a whole, since for reasons of space economization the spindle gauge is small. However, for the individual sets of friction disks to be swung out of their overlapped position, each set has to be driven by an individual motor that pivots with the set. If toothed belts are used as the drive coupling between the sets, these belts must be removed before the sets are swung out.
The task on which the invention is based therefore is, in a process or in devices of the same species free of the aforesaid disadvantages, to effect the changeover between "S" and "Z" twist in as simple a manner as possible without the need for costly and time-consuming mounting of textile machine components such as, for example, disk sets or drive parts. At the same time, the yarn production quality obtained after the changeover to "S" or "Z" twist should remain
REFERENCES:
patent: 4047374 (1977-09-01), Venot
patent: 4704858 (1987-11-01), Naylor et al.
patent: 5099642 (1992-03-01), Rader et al.
patent: 5255503 (1993-10-01), Rader et al.
patent: 5349808 (1994-09-01), Lorenz
patent: 5414989 (1995-05-01), Rader et al.
Rader Wolfgang
Schmitt Gunther
Stodola Daniel P.
Taylor Tina R.
TEMCO Textilmaschinenkomponenten GmbH & Co. KG
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