Textiles: spinning – twisting – and twining – Apparatus and processes – Strand guiding or guarding
Reexamination Certificate
2000-09-21
2001-12-25
Worrell, Danny (Department: 3741)
Textiles: spinning, twisting, and twining
Apparatus and processes
Strand guiding or guarding
Reexamination Certificate
active
06332312
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a process and to a device for spinning with suppressed yarn balloon whereby the rotation of the yarn is predominantly generated between a spindle attachment and the nip of supply rolls at the output of the drafting frame, whereby the spindle attachment in its head region is provided with one or more projections and with these projections the spindle extends upwardly up to a vertically adjustable thread guide on the extension of the spindle axis and whereby, preparatory to an automated bobbin change, the vertically adjustable yarn guide is displaced away from the spindle attachment upwardly and the ring rail is then lowered into the underwinding position.
BACKGROUND OF THE INVENTION
It has long been known and has been common, for the production of yarns, to utilize spinning processes in which the spindles are provided below the usually fixed thread guide with respective spinning heads. These spinning heads rotate with the spindles or in certain variants approximately with the speed of the spindles and bring the twist in the yarn relatively close to the nip of the supply rollers.
The thread balloon is thereby suppressed and the yarn can be wound up with reduced tension on the bobbin. Advantages are also obtained from the viewpoint of the travel characteristics of the traveller.
Such a process has not become widely used in practice. The reasons for this differ substantially.
The use of spinning heads results in a movement of the twist of the yarn from close to the nip of the rollers from which the slubbing is supplied to the spinning zone. The spun yarn which results is then guided via the entrainer of the spinning head in a spiral pattern from a part of the bobbin sleeve to the traveler of the spinning ring. It has been found that this spinning process gives rise to a very hairy yarn.
The use of the process is limited, therefore, to the spinning of such yarns in which the hairiness is desirable. These are yarns for carpentry, for covers or for felts (see the brochure of the Rieter firm for Carded Yarn Ring Spinning Machine H3 from the year 1967).
For the production of very fine and smooth yarn, especially combed yarn, for fabrics the hairiness of the yarn is undesirable. The spinning process with a suppressed yarn balloon is therefore not used for this purpose.
With the aim of increasing the quality of yarn spun by means of a spinning head, attempts have been made to displace the thread guide above the spinning head in a transition from balloon reduced spinning to spinning with a yarn balloon (DE 34 15 977 A1 and 34 15 998 A1). This approach has also not been crowned with success. The hairiness of the yarn by spinning with a spinning head and suppressed yarn balloon is not avoided by the displacement of the yarn guide.
For the aforementioned reasons it is preferred for the spinning of finer yarns, especially finer carded (worsted) or combed yarn, to carry out the spinning with a reduced yarn balloon with the aid of so-called balloon-limiting rings. However, increases in spinning speed and increases in the output of the spinning machine are thereby limited.
In the use of this process there has been increasing employment of so-called compaction zones in the region of the output rolls of the drafting frame (DE 882 066) or following the drafting frame (EP 0 635 590 A2 or 197 08 410 A1). These compaction zones seek to draw the fibers of the drafted slubbing into a reduced width in the nip of the supply rollers (rollers which feed the slubbing into the spinning zone). The result is a very small spinning triangle. The danger of yarn breakage is thus significantly reduced at these locations.
OBJECTS OF THE INVENTION
An object of the invention is to provide a spinning process with a spinning head and suppressed yarn balloon which is suitable for producing very fine and smooth yarn with higher reliability at higher spindle speeds and with automated bobbin change.
It is also an object of the invention to provide an apparatus for reliably carrying out the process with reduced structural cost and whereby phases between the normal spinning process and bobbin change can be effected in an optimum manner.
A method of spinning with a suppressed yarn balloon, whereby the twisting of the yarn is predominantly effected between a spindle attachment and the nip of said rollers at the output of the drafting frame, whereby the spindle attachment in its head region is provided with one or more projections and extends with these projections along the extended axis of the spindle upwardly to a vertically shiftable yarn guide, and whereby in preparation for an automated bobbin change the vertically shiftable yarn guide is moved away from the spindle attachment, is displaced upwardly and the ring rail is then lowered into the underwinding position.
According to the invention, the drafted slubbing leaving the drafting frame is compacted to maintain a parallel fiber orientation and thus is fed into the nip of the feed rollers which follow the drafting frame with a spacing.
The combination of balloonless spinning with compaction spinning gives rise to surprising results which would not have been expected by the artisan. In the spinning without a yarn balloon, higher twists in the yarn, especially in the region between the yarn guide above the spinning head and the nip of the supply rollers, are obtainable. Because of the reduced spinning triangle that results from compaction spinning, all of the fibers are oriented strictly parallel to the yarn as it is further displaced directly downstream of the nip of the supply roller pair in the spinning process. They together ensure the stability of the yarn. The resulting yarn is very smooth. The hairiness customary in such yarn is practically completely eliminated. The number of yarn breaks at the output of the supply rollers is practically zero.
With the aforementioned combination of process steps, very thin yarns can be spun in a problemless manner with higher quality.
The method, according to the invention in preparation for stopping of the spinning machine, the spindle speed is reduced by more than 50%, with the reduced spindle speed, the spacing between the yarn guide and the spindle attachment is significantly increased, and the spinning process is altered from suppressed yarn balloons spinning to spinning with a speed- determined small-yarn-balloon spinning. In preparation for the restarting of the spinning machine, the increased spacing between the yarn guide and the spindle attachment is initially maintained, at low spindle speed and during the spinning process with a yarn balloon the first turns are applied with speed controlled small yarn balloon, and then after the lowering of the thread guide against the spindle attachment, spinning with suppressed yarn balloon at normal spinning speed is carried out.
Depending on the type and manner of the change in the spinning process before and after a stopping process for the purpose of bobbin change the optimum conditions in spinning with a reduced yarn balloon and also for the process transition and for spinning with a yarn balloon without additional assistance, like controlled balloon-limiting rings, can be ensured.
The parameters according to the invention which result in further optimization of this process at the stopping procedure before a bobbin replacement and:
before the bobbin change the spindle speed is reduced to a value between 1500 and 1600 rpm, in a second step the thread guide is raised above the spinning head parallel to the spindle axis by about 20 to 50 mm until a yarn balloon is formed, and after the formation of the yarn balloon, the ring rail is lowered into the underwinding region.
Upon beginning of spinning startup after a bobbin change the spindles initially are driven with a lower speed and the yarn guide remains positioned at the increased distance above the spinning head and the ring rail during the spinning with a yarn balloon is raised from the unwinding position into the spinning startup position on the lower region of the bobbin sleeve, a
Dubno Herbert
Worrell Danny
Zinser Textilmaschinen GmbH
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