Textiles: spinning – twisting – and twining – Apparatus and processes – Alternate twist
Reexamination Certificate
2000-12-19
2001-11-06
Falik, Andy (Department: 3765)
Textiles: spinning, twisting, and twining
Apparatus and processes
Alternate twist
Reexamination Certificate
active
06311467
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a method for producing a filament yarn with alternating S- and Z-twists, in which at least one yarn is moved between two spaced apart twisting stops arranged at a distance from each other, and the yarn receives thereby through at least one false twisting unit of the clamping type arranged between the twisting stops alternately S- and Z-twists which are fixed by means of a fixing unit which is interconnected downstream of the false twisting unit in yarn advancing direction.
BACKGROUND OF THE INVENTION
In such a method known from the DE 39 31 110 C2, the twisting stops are formed by two stationarily arranged delivery mechanisms, of which one is arranged upstream of the false twisting unit or units, and the other one downstream of the fixing unit, which is designed either as a heating device or as an air-circulating device. The alternating formation of the S- and Z-twists is carried out in a predetermined cycle by switching on and off the clamping action of the false twisting unit. Since, however, the second twisting stop is arranged downstream of the fixing unit in yarn advancing direction, the S- and Z-twists earlier applied to the yarn are, depending on the twisting direction, partially again untwisted and partially yet more tightly twisted in the yarn section extending downstream of the false twisting unit. Thus it is not possible in this manner to produce a yarn which has reproducible alternately defined S- and Z-twists. Furthermore nontwisted sections with a lesser S- or Z-twist are each created between the sections with S-twist and the sections with Z-twist.
SUMMARY OF THE INVENTION
The basic purpose of the invention is therefore to provide a method for producing a filament yarn with alternating S- and Z-twists, with which in a simple, economical and reproducible manner a filament yarn can be produced which has defined S- and Z-twists per unit of length and therebetween as much as possible no nontwisted or little twisted sections.
This is attained according to the invention by the twisting stop provided in yarn advancing direction downstream of the false twisting unit being moved synchronously with the yarn and being held in an engagement with the yarn stopping the twisting until at least the twisting inversion point in the yarn is fixed, and by at least one further twisting stop, following the aforementioned moved twisting stop at a distance, entering into an engagement with the yarn stopping the twisting, and advancing together with same before the yarn is twisted in an opposite direction by the false twisting unit.
Thus the invention is based on the thinking to grasp the yarn directly behind the false twisting unit by twisting stops successive in timely and spacial intervals, and to then advance the twisting stops synchronously together with the yarn. A twisting stop has the purpose to prevent a continuation of a twist applied to the yarn into a yarn section lying upstream of or downstream of the twisting stop. Clamping devices are primarily used as twisting stops in the present case, however, a twisting stop can also be designed as a guide edge or through clamping in a delivery mechanism. Yarn sections are in the inventive method each temporarily “fixed” between two spaced twisting stops which follow each other until the final fixation by means of the fixing unit takes place. The yarn sections extending fixed between two twisting stops have either a S- or Z-twist with a specific twist, whereby the term “twist” means according to DIN 60900, Part 2, the number of twists of a single yarn per/m. The specific twist of a section of yarn clamped between two adjacent twisting stops is not influenced or changed by the twists applied to the following yarn sections because the false wire is constructed always only up to the twisting stop closest to the false twisting unit. In this manner also nontwisted sections between the yarn sections with S- or Z-twist are avoided. The inventive method can be continuously carried out and enables the production of a filament yarn with alternating S- and Z-twists. The filament yarn can be produced out of a yarn component, namely a bunch of filaments, and is fixed during the production process following the false twisting unit, which is done by thermofixation.
REFERENCES:
patent: 4114358 (1978-09-01), Tscuhida et al.
patent: 4266398 (1981-05-01), Vogelsberg
patent: 4279120 (1981-07-01), Norris
patent: 4351146 (1982-09-01), Faure et al.
patent: 5752496 (1998-05-01), McPherson
patent: 14 35 728 (1969-01-01), None
patent: 39 31 110 (1990-03-01), None
Falik Andy
Flynn, Theil, Boutell & Tanis, P.C.
Saurer-Allma GmbH
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