Patent Grant
7051508
This application claims the priority of German Application No.: 103 29 612.3 filed on Jun. 23, 2003, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a yarn withdrawal device for open-end spinning arrangements, comprising a yarn withdrawal nozzle, which contains a curved contact surface for guiding yarn which is to be withdrawn and which yarn simultaneously rotates in a crank-like manner, said contact surface graduating from a front surface into an axial channel, also comprising a balloon-breaking insert which extends the axial channel, the inner wall of the balloon-breaking insert being provided with raised areas/and or recesses with which the yarn comes into contact.
In open-end spinning, yarn withdrawal devices comprising yarn withdrawal nozzles in a great variety of embodiments are prior art. A plurality of such known yarn withdrawal nozzles, together with their advantages and disadvantages are described in German published patent application 197 38 382 (corresponding U.S. Pat. No. 6,035,625).
In the above mentioned publication it is disclosed that yarn withdrawal nozzles having smooth contact surfaces produce good quality yarn, but that yarn withdrawal nozzles of this type permit only a relatively low level of spinning stability, as the initial torsion upstream of the contact surface is too low due to the smoothness of the contact surface. Smooth yarn withdrawal nozzles are therefore particularly subject to end breaks.
The known publication describes further that so-called notch nozzles, that is, such yarn withdrawal nozzles whose contact surfaces are provided with notches or ribs increase the spinning stability, that is, they reduce the number of end breaks. This, however, is at the cost of the yarn quality, namely the tear resistance and the evenness of the spun yarn. Despite this, notched nozzles of this type have proven to be a good compromise and serve as the standard design in many applications.
It is further known from the publication that the notches can be present not only in the contact surface, but also in the annexing axial channel. This increases further the spinning stability, but at the cost of further reduced yarn quality. Notches and/or ribs in the axial channel ensure, however, a certain degree of hairiness of the spun yarn, which results in a “softer feel” which is often the intention.
The known publication further mentions that the so-called spiral nozzles are known in which the notches and/or ribs extend in the manner of a helix, and thus ensure a somewhat greater spinning stability than the smooth yarn withdrawal nozzles. The spinning stability is however less than in the case of such yarn withdrawal nozzles, in which the contact surface is notched. Spiral nozzles have, however, a relatively good yarn quality. The above mentioned publication further discloses that the spiral can project into the axial channel.
Also known from the above mentioned publication is a combination of notches and spirals, whereby serviceable yarn quality values with good spinning stability are assumed.
As the yarn withdrawal nozzles deflect the withdrawn yarn at approximately 90°, the yarn runs crank-like on the front surface of the yarn withdrawal nozzles at high speed. This results in that in the axial channel of the yarn withdrawal nozzle a certain balloon formation of the withdrawn yarn takes place. This has been taken advantage of in that so-called balloon-breaking inserts are arranged downstream, which are known in the industry as “whirl inserts”. A balloon-breaking insert of this kind is prior art in German published patent 32 20 402 (corresponding U.S. Pat. No. 4,516,397). This balloon-breaking inserts are especially then applied when it is intended that the spun yarn should have an increased hairiness. The surface structure of the spun yarn is changed by the balloon-breaking insert in that the yarn is roughened. This is basically fiber damage, so that the greater hairiness is gained with an inevitable reduction in tear resistance and evenness of the yarn. Such balloon-breaking inserts are basically spinning components which treat the yarns very roughly.
It is further known from German published patent 34 19 300 that the effect of such balloon-breaking inserts can be decreased by means of suitable ball-shaped inserts, whereby, depending on the design of the inserts, yarns with more or less hairiness can be spun. This publication discloses also that in addition the twist propagation, that is the spinning stability, can be influenced. The balloon-braking insert disclosed in this publication can be combined as required with yarn withdrawal nozzles having contact surfaces either with or without notches.
It is an aim of the present invention, based on the latter named publication, to pursue the further design of these undoubtedly correctly designed devices. One aim in particular is to spin yarn with a certain, but not too great, degree of hairiness, while at the same time, however, achieving good yarn values and good spinning stability.
This aim has been achieved in accordance with the present invention in that, in the case of a yarn withdrawal device of the above mentioned type, the contact surface of the yarn withdrawal nozzle is a smooth steel surface, and that the inner wall of the balloon-breaking device is provided with blunted raised areas/and or recesses reduced in such a way that a hairiness in the range of 3 mm in length can be achieved, while at the same time achieving values for spinning stability, wear resistance and evenness that are comparable to those resulting from notched contact surfaces of standard yarn withdrawal nozzles without balloon-breaking inserts.
The yarn withdrawal nozzle according to the present invention comprises firstly the advantage of a smooth contact surface, that is, without notches or ribs, which is responsible for a good yarn quality. A smooth contact surface of this type ensures yarn-friendly treatment of the withdrawn yarn in the particularly critical area. The steel surface permits sufficient hardness and thus wear-resistance of the contact surface, while at the same time ensuring a good carrying-off of heat, which is required in particular when spinning polyester fibers. The blunted balloon-breaking insert arranged downstream delivers the desired level of hairiness without too high a level of fiber damage. By means of simple tests, the right combination of a smooth yarn withdrawal nozzle with a suitable balloon-breaking insert can be found, whereby yarn quality and spinning stability values are achieved which are comparable to the notched yarn withdrawal nozzles without balloon-breaking inserts. The characteristics of the contact surface of a standard yarn withdrawal nozzle are thus transferred to a great extent to the balloon-breaking insert, which is present only for the purposes of achieving a certain pre-defined hairiness, while the contact surface of the yarn withdrawal nozzle itself is designed with regard to good yarn quality. The combination of a smooth yarn withdrawal nozzle comprising a contact surface of steel and having a reduced-effect balloon-breaking insert permits, by way of its flexibility, an even more specific adaptation of the yarn withdrawal device to the respective application than was previously possible.
It should be mentioned at this point that notched contact surfaces made of steel wear relatively quickly, as the notch forms are eroded so that spinning stability is no longer ensured after a short time. Contact surfaces of yarn withdrawal nozzles were therefore made of ceramic material as standard, which is less favorable with regard to heat elimination. In the case of the yarn withdrawal device of the present invention, it is in contrast now possible not only to make the contact surfaces from steel, but also to allocate the wear-prone part to the balloon-breaking insert, which part can then consist, at least on its inner wall, of a ceramic material.
In an embodiment of the present invention, a diameter contraction is provided between the axial channel of the yarn withdrawal nozzle and the balloon-breaking insert. The contraction causes the withdrawn yarn to be guided more in the center of the balloon-breaking insert so that the raised areas and/or recesses have a less aggressive effect. The contraction thus serves to blunt the effect of the balloon-breaking insert and can be achieved in a simple way in that the contracted part is placed in a separate intermediary ring. This has the additional advantage in that standard whirl inserts, which are actually aggressive, can be applied, the effects of which are blunted in the required way by means of this intermediary ring.
In a further embodiment of the present invention it can be provided that downstream of the balloon-breaking insert a centering device for permitting a centrical yarn withdrawal is provided. A centering device of this type also serves to blunt the effect of the raised areas and/or the recesses of the balloon-breaking insert. The centering device can in this case also be formed by means of a contraction, which in turn can be provided in a separate centering ring. The centering device can alternatively be formed by means of a yarn deflecting wall of a yarn withdrawal channel.
Many various embodiments can be chosen for the raised areas and/or recesses of the balloon-breaking insert. Ribs or notches can be provided which are arranged symmetrically or asymmetrically and if required, also helically, possibly extending in multiple helixes.
A particular advantage of the yarn withdrawal device of the present invention is then to be achieved when the yarn withdrawal nozzle and/or the balloon-breaking insert is designed as a replacement part. The most suitable yarn withdrawal device can be chosen and assembled for practically every desired yarn type.
These and further objects, features and advantages of the present invention will become more readily apparent from the following detailed description thereof when taken in conjunction with the accompanying drawings.
The partly shown open-end spinning device in
The rotor cup 2 comprises a fiber sliding surface 7 which widens conically towards a fiber collecting groove 6. The hollow interior of the rotor cup 2 has its largest diameter in the fiber collecting groove 6. The spinning rotor 1 can be removed through a front opening 8 of the rotor housing 5 towards the operator's side of the open-end spinning device. During operation, the opening 8 of the rotor housing 5, together with the open front side 9 of the rotor cup 2 is closed over by a movable cover 10. The movable cover 10 is disposed on the rotor housing 5 with a sealing ring 11 therebetween.
The cover 10 comprises a fiber feed channel 12, which lies outside of the plane of projection, which begins in a way not shown at an opening roller and whose mouth 13 is directed against the fiber sliding surface 7. Due to the effect of the above mentioned vacuum source, single fibers which have been combed out of a sliver by the opening roller are caused during operation to fly through the fiber feed channel 12 against the fiber sliding surface 7, from where they slide into the fiber collecting groove 6, form there a fiber ring and are then withdrawn in axial direction of the shaft 3 in the known way as yarn 14, denoted by a dot-dash line. The transport air sucked in via the fiber feed channel 12 can flow off via an overflow gap 15 on the open front side 9 of the spinning rotor 1.
The spun yarn 14 is withdrawn out of the fiber collecting groove 6 at least approximating a plane vertically to the shaft 3 of the spinning rotor 1 and subsequently via a yarn withdrawal channel 16 according to the delivery direction A by means of a delivery roller pair (not shown) and fed to a winding bobbin (also not shown). The yarn withdrawal channel 16 is disposed at least in its initial area coaxially to the shaft 3 of the spinning rotor 1, so that the yarn 14 leaving the fiber collecting groove 6 is initially deflected at an angle of approximately 90°, whereby the yarn 14 in the above mentioned vertical plane simultaneously rotates in a crank-like motion.
A yarn withdrawal nozzle 17 serves to deflect the yarn 14 from the above mentioned vertical plane into the yarn withdrawal channel 16, said yarn withdrawal nozzle 17 beginning with a funnel-shaped, curved contact surface 18 on a front surface 19 disposed in the vertical plane. In the axial section shown in
It should be mentioned here that the speed of the crank-like rotation motion of the yarn 14 is very much greater than the speed of the yarn 14 in delivery direction A.
As can be seen in
In the past the aim was to achieve the good characteristics of the spun yarn 14 as well as spinning stability through the design of the yarn withdrawal nozzle 17, while hairiness, in as much as it was desired, could be effected by a balloon-breaking insert 22 arranged downstream. Now, according to the present invention, the effect of the raised areas and/or the recesses 23 of the balloon-breaking insert 22 is blunted, so that the achieved hairiness of the spun yarn 14 remains within reasonable limits, while yarn quality is achieved by means of a smooth steel surface of the contact surface 18. It has been hereby shown that it is possible solely by means of a combination of a smooth contact surface 18 made of steel and a blunted-effect balloon-breaking insert 22 arranged downstream thereof to spin yarns which, with regard to spinning stability, tear-resistance and evenness were only attainable until now by using standard notched yarn withdrawal nozzles without balloon-breaking inserts. Because of a contact surface 18 of the yarn withdrawal nozzle 17 designed as a smooth steel surface and an effect-blunted balloon-breaking insert 22, there is great flexibility with regard to the yarn withdrawal device 24, as the desired low level of hairiness together with sufficient spinning stability with good yarn qualities can be achieved. The balloon-breaking insert 22 is hereby advantageously made of ceramic material.
It is additonally provided in
In the embodiment according to
With the aid of FIGS. 4,5 and 6 it can be seen that the raised areas and/or the recesses 23 are designed in many different embodiments. According to
In the case of all shown embodiments it is preferable that the yarn withdrawal nozzle 17 as well as the balloon-breaking insert 22 are each designed as replaceable parts.
The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 103 29 612 | Jun 2003 | DE | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 4516397 | Raasch et al. | May 1985 | A |
| 4773211 | Stahlecker et al. | Sep 1988 | A |
| 4796421 | Stahlecker et al. | Jan 1989 | A |
| 4843812 | Raasch | Jul 1989 | A |
| 4854119 | Stahlecker et al. | Aug 1989 | A |
| 5044151 | Pohn et al. | Sep 1991 | A |
| 5321943 | Schmid et al. | Jun 1994 | A |
| 6035625 | Schloemer et al. | Mar 2000 | A |
| Number | Date | Country |
|---|---|---|
| 32 20 402 | Mar 1985 | DE |
| 34 19 300 | Jan 1987 | DE |
| 197 38 382 | Mar 1999 | DE |
| Number | Date | Country | |
|---|---|---|---|
| 20040255569 A1 | Dec 2004 | US |
