US3501905A

US3501905A - Sliver spinning method and apparatus

Info

Publication number: US3501905A
Application number: US633242A
Authority: US
Inventors: Hans Landwehrkamp; Franz Schreyer; Rolf Canzler
Original assignee: Schubert und Salzer Maschinenfabrik AG
Current assignee: Rieter Ingolstadt Spinnereimaschinenbau AG
Priority date: 1966-04-26
Filing date: 1967-04-24
Publication date: 1970-03-24
Anticipated expiration: 1987-03-24
Also published as: FR1520291A; GB1175406A; ES339621A1; CH451765A; JPS5134012B1

Description

March 24, 1970 DWEH KAMP'ETAL 3,501,905

SLIVER SPINNING METHOD AND APPARATUS Filed April 24. 1967 4 Sheets-Sheet 1 Fig. 1 F 37 INVENTORS H/WS LANDh/[llR/(ANP FRANZ SZHREYER RfllF (AA/2L5? March 24, 1970 H. LANDWE HRKAMP ET AL 3,501,905

SLIVER SPINNING METHOD AND APPARATUS Filed April 24. 196'? 4 Sheets-Sheet z IN VEN TORS. HAM; FRANZ $CHRYI Rolf CAIYZZER By w uap, $1.7

ATTUR NE Y6 March 24, 1970 H LANDWEHRKAMP vETAL 3,501,905

SLIVER SPINNING METHOD AND APPARATUS Filed April 24. 1967 4 Sheets-Sheet 3 Fig. 3

INVENTORS: HANSZANDWFHR/(ANP, FAA/VZ 50mm? AflLF (/INZLER ATTQRNEYJ March 24, 1970 H. LANDWEHRKAMP ETAL 3,501,905

SLIVER srnmme METHOD AND APPARATUS 4 Sheets-Sheet 4 Filed April 24. 1967 Fig. 5

IN VEN TORS HANS LANDWfl/RKA HP FRANZ SCHPE/El? RDLFCA/YZZER upa whb gg ATTORNEyS United States Patent 3,501,905 SLIVER SPINNING METHOD AND APPARATUS Hans Landwehrkamp, Franz Schreyer, and Rolf Canzler, Ingolstadt, Germany, assignors to Schubert & Salzer Maschinenfabrik Aktiengesellschaft, Ingolstadt, (Danube), Germany, a corporation of Germany Filed Apr. 24, 1967, Ser. No. 633,242 Claims priority, application Germany, Apr. 26, 1966, Sch 38,889; Aug. 17, 1966, Sch 39,416

Int. Cl. D01b 7/00 US. Cl. 5758.89 22 Claims ABSTRACT OF THE DISCLOSURE A sliver spinning method and apparatus wherein the fibre sliver is introduced into a rotary spinning chamber by a powered infeed means and is accumulated within the chamber in the form of a fibre ring held against the chamber wall by centrifugal force, which fibre ring is contacted during spinning by the end of the spun thread for continuous gathering of fibres which are twisted to continuously add to the length of the spun sliver delivered from the spinning chamber by a powered outfeed means. When spinning is interrupted, the operation of the infeed and outfeed means is halted before the rotation of the spinning chamber is stopped to assure retention within the spinning chamber of the spun sliver end, and when spinning is resumed, the spinning chamber is set into rotation before operation of the infeed and outfeed means is resumed to assure contact between the spun sliver end and the fibre ring for continued fibre gathering and twistmg.

The present invention relates to a sliver spinning method and apparatus wherein fibre sliver is introduced into a rotary spinning chamber in broken-up form by a powered infeed means and is accumulated Within the chamber as a fibre ring held against the chamber wall by centrifugal force. Spinning of continuous thread length is accomplished by contacting the fibre ring during cham ber rotation with the end of a spun thread length which has been introduced into the chamber through an outfeed guide tube by hand. When the chamber is rotated, vortex air currents are induced therein which urge such thread end radially outward into fibre-capturing contact with the fibre ring, which captured fibres are twisted by the chamber rotation to form a continuous new spun thread length connected to the initial thread end. Such new spun sliver is withdrawn as it is formed by a powered outfeed means which receives the spun sliver passed through the outfeed guide tube.

In the continuous spinning processes of the prior art for spinning a fiber sliver into a yarn with the use of rotating spinning chambers, the broken-up sliver is introduced through an infeed tube into the spinning chamber, partially with the co-operation of a current of air, and with the formation of a fiber ring at the point of maximum diameter of the spinning chamber as a result of a vacuum or of centrifugal forces. The twisted fiber yarn is developed by the fact that a thread end which rotates as a result of the spinning chamber rotation incorporates fibers from the fiber ring and is continuously withdrawn concentrically to the spinning chamber. The fiber ring, the rotating thread end, and also the infeed and outfeed of the fiber yarn, are in a certain equilibrium of forces during the spinning process. If, however, the spinning machine is shut off and brought to a stop for operational reasons, this equilibrium of centrifugal forces, vacuum and thread tension, is destroyed. The twisted thread is pulled out of the spinning chamber. It is then possible to restart the spinning machine only by introducing a piece of thread manually into the spinning chamber at every single spinning station, and restoring the connection between it and the fiber ring forming in the spinning chamber. This pulling out of the thread end also takes place if one resorts to the obvious measure of shutting off the outfeed system before shutting oil? the spinning chamber, since the thread springs together as a result of excessive twist. In the case of multiple-spindle machines, particularly when all the machines of entire spinning rooms have to be set in operation manually in this manner, spinning station by spinning station, at the beginning of a shift, a problem arises out of this fact which makes it entirely doubtful whether the use of spinning devices of this kind is economically feasible.

It is the aim of the present invention to find a procedure and a corresponding apparatus to permit the stopping and restarting of such spinning devices.

This problem is solved according to the invention in that, when the spinning device is shut 013?, the infeed device and the outfeed device are stopped before the spinning chamber is stopped, and the thread end that is inside of the spinning chamber is stretched out in an approximately axial direction within the spinning chamber by appropriate means, and that, in restarting, the spinning chamber is put into motion before the infeed device and the outfeed device. If the spinning chamber does not produce a vacuum by itself, then in the restarting operation the spinning chamber is not started until the suction device has been turned on. A variation of the process of the invention consists in delivering a certain length of the thread back out of the outfeed tube into the reach of a clamping means and clamping it, after the spinning chamber is stopped and with the suction device turned on, and, when restarting the machine, opening the clamping means before starting up the infeed device and the outfeed device. Furthermore, the backdelivery of the thread can take place during a compressed air blast directed contrary to the yarn outfeed, which enters into the spinning chamber and emerges through the thread-end holding orifice, this blast of compressed air replacing the suction. In this manner it is brought about that the thread end remains inside of the spinning chamber even while the spinning machine remains stopped, and the attachment between the thread end and fiber ring is automatically restored when the machine is restarted.

For the practice of the method according to the invention, an orifice is provided on the side of the spinning chamber opposite the side on which the yarn emerges, and is disposed concentrically or excentrically to the axis of rotation of the spinning chamber, this orifice serving to receive the thread end remaining in the spinning chamber while the machine is stopped. A current of compressed or aspirated air emerging from the orifice serves for the outstretching or for the holding of the thread. A thread clamping means disposed behind the orifice can additionally serve for holding the thread end while the spinning device is stopped. The outstretching of the thread end remaining in the spinning chamber can also be performed mechanically by the yarn out feed tube Whose orifice is axially displaceable from the one side of the spinning chamber all the way into the thread-end holding orifice on the opposite side. One particularly advantageous execution of the invention consists in having the spinning chamber rotate about a non-rotating yarn outfeed tube and closing it off by means of a stationary cover on its open side, the said cover having a funnel-like thread end holding orifice disposed concentrically to the axis of rotation, and having a sliver infeed orifice disposed excentrically to the axis of rotation. This arrangement has the advantage that the thread end that is inside of the spinning chamber is stretched out upon shutdown between two stationary parts and thus the twisting is immediately interrupted upon the separation between the fiber ring and the thread end.

In British Patent 477,259 a spinning device has already been described which has a rotating spinning chamber and in which the feeding of the sliver takes place excentrically and an orifice is provided on both sides of the spinning chamber. In both cases, however, what is involved is a fiber yarn outfeed orifice which is located optionally on the one or on the other, opposite side.

It is therefore, an object of the invention to provide a sliver spinning method whereby after starting an initial length run of spun thread successive continuously connected length of spun thread can be formed and delivered from a rotary spinning chamber.

Another object of the invention is to provide a spinning apparatus for performing the aforesaid thread spinning method.

A further object of the invention is to provide a spinning apparatus as aforesaid wherein the last-formed spun thread length end is separated from its fibre supply within the spinning chamber and retained therein whenever spinning production is interrupted to allow resumption of spinning production without the need for any servicing within the spinning chamber.

A further object of the invention is to provide a spinning apparatus as aforesaid in which the separation of the last-formed spun thread length end is accompllished by means of an air current introduced into the spinning chamber.

A further object of the invention is to provide a spinning apparatus as aforesaid wherein the sliver length end retained within the spinning chamber is restored to contact with the fibre supply within the chamber by the action of vortex air currents induced by the rotation of the spinning chamber.

Still another and further object of the invention is to provide a spinning apparatus as aforesaid in which the operation of the spun sliver outfeed means and the fiber infeed means is halted before rotation of the spinning chamber is stopped to interrupt spun sliver production without clogging the spinning chamber with excess fiber and without removing from the chamber the last-formed sliver length used for starting the next spun sliver length run upon presumption of spinning chamber rotation.

Other and further objects and advantages of the invention will become apparent from the following detailed description and accompanying drawing in which:

FIG. 1 is a sectional view of a spinning apparatus according to a preferred embodiment of the invention.

FIG. 2 is a sectional view of a spinning apparatus according to another embodiment of the invention.

FIG. 3 is a sectional view of a spinning apparatus basically similar to that shown by FIG. 1, but having eccentrically located thread end holding means.

FIG. 4 is a sectional view of a spinning chamber and spun sliver outfeed guide tube combination in accordance with the invention which can be substituted for those shown in FIGS. 1-3, as seen with the guide tube in its normal spinning position.

FIG. 5 shows the spinning chamber and spun sliver outfeed guide tube combination of FIG. 4 as seen with the guide tube in its thread end holding position.

FIG. 6 is a longitudinal view, partly in section, of a portion of the spinning apparatus shown in FIG. 1 and illustrating a clamping device which can be used to assure positive retention within the spinning chamber of the last-formed sliver length end.

In FIG. 1, the rotating spinning chamber 2 having its stem 21 mounted pendantly in a housing 1 which is closed by a cover 11. Cover 11 is made stationary by housing 1 in relation to the rotating spinning chamber 2 and simultaneously forms the closure of spinning chamber 2. Cover 11 has a funnel-like orifice 4 disposed concentrically to the axis of rotation of the spinning chamber 2, the

4 said orifice being connected to a suction line 42. A sliver feed tube 51 empties eccentrically into spinning chamber 2 at cover 11.

The driving of spinning chamber 2 is performed through a pulley 22 mounted on the end of the tubular stem 21, which is driven by a belt 23. A tube 31 mounted stationarily on machine frame 12 is disposed inside of the tubular stem 21 for the emergence of the yarn F from the spinning chamber 2.

The manner of operation of the spinning device is as follows. The fiber sliver S is fed in the broken-up state through a feeding device 5 and feed tube 51 eccentrically into the rotating spinning chamber 2 in which, as a result of centrifugal force a fiber ring R forms at the point of largest diameter. The feeding of the fibers into the spinning chamber 2 is produced by a flow of aspirated air through the suction line 42. The end E of the finished, twisted thread F is joined with the fiber ring R and thus receives its rotation from the rotating spinning chamber, and this rotation results in the twisting of thread F and in the binding in of the fibers from the fiber ring R rotating with the spinning chamber 2. Although thread F is continuously taken out by an outfeeding device 3, the centrifugal force always keeps the thread length E tensed and in contact with the fiber ring R, which is continuously being diminished by the emerging thread F, but at the same time is constantly being replenished by the infeeding of the sliver S.

This equilibrium of forces subsists for as long as the spinning device is in operation. If the latter, however, is stopped, it is apparent that this equilibrium is suddenly disturbed, and the thread end E slips out of the spinning chamber 2 into the thread outfeed tube 31, either as a result of excessive twisting by the spinning chamber as it runs down while the outfeed device has already stopped, or because of the fact that thread F contracts as a result of the relaxing of the tension exercised by the centrifugal force. When the spinning machine is restarted, however, the spinning process cannot be resumed in these circumstances, unless a piece of thread is introduced manually through the thread outfeed tube 31 down into the spinning chamber 2 and extremity E is fortuitously hurled outward by contact with the rotating spinning chamber and thus acquires contact with the fiber ring R. This, however, is a diflicult and, especially in the case of a large number of spinning stations, a tedious procedure. Furthermore, caution must be exercised to prevent the spinning chamber 2 from being clogged by infed fibers due to the lack of outfeed, and to prevent the development of thin spots or thick spots in the thread due to the interruption of the spinning process.

Now, it has developed that these disadvantages can be prevented if the stopping and restarting is performed according to a certain procedure and certain precautions are taken in the designing of the spinning chamber. The shutting down of the spinning device is performed first by stopping the infeed system 5 and the outfeed system 3, while the spinning chamber 2 continues to run. In this manner, when the thread outfeed is interrupted the spinning chamber does not become clogged, and on the other hand the already existing fiber ring R is still being bound into the thread end B and twisted. The spinning chamber 2 is not to remain no longer in operation than it takes to complete this process, so as to prevent an excessive twisting of thread F. This process takes about one to two seconds. As the spinning chamber r.p.m. diminishes to zero, the thread end E leaves the gathering trough 24 of spinning chamber 2, since the effect of centrifugal force vanishes. To prevent a contraction and snarling of thread end E, the latter is stretched in an approximately axial direction in the spinning chamber 2. This can be accomplished in various ways.

According to the embodiment in FIG. 1, a funnel-like orifice 4 is provided on the side opposite the yarn outfeed tube 31, and thread end E is sucked into it. Owing to the fact that, when the shutdown occurs, the ring of fibers R is still being spun, the thread end B has become substantially longer, so that it reaches all the way into the orifice 4. The thread end can move freely in the current of aspirated air, so that a certain untwisting can take place, along with the relaxation associated therewith, if the threaded has been excessively twisted while the spinning chamber 2 was running down. In the case of a pendant arrangement of the spinning chamber 2, the suction can finally also be shut off after the spinning chamber stops, so that the uncrimped thread end E remains hanging free in the spinning chamber 2. The aspiration through orifice 4 and suction tube 42 simultaneously serve the purpose of cleaning out any fibers and dirt remaining in the spinning chamber.

When the spinning device of FIG. 1 is restarted, it is best first to turn on the suction, so that thread end B is sure to be stretched; then spinning chamber 2 is started up, which produces an air vortex which finally is so strong that the stretched thread end B is flung into the gathering trough 24. Then the sliver feed 5 for forming the fiber ring R is turned on, and so is the outfeeding device 3, and the spinning process is continued.

The process described can be used successfully in spinning chambers of many dilferent types of construction. FIG. 2 shown by way of example a spinning chamber 2 having radial openings 25 through which air emerges into housing 1 and is carried away by a suction tube 43. On the fiber yarn outfeed tube 31, an injector 32 is attached to its one extremity, and is connected to a compressed air line 33. The thread end B in this case is stretched by a stream of compressed air rather than by suction, and is thereby introduced into the thread end holding orifice 4. In back of orifice 4 there can be additionally provided a thread clamping device consisting, for example, of a rubber membrane '6 which is constricted by compressed air fed into the pressure chamber 61 surrounding it, and which thus clamps the thread end E. Also, a plunger 63 can be provided, which is operated electromagnetically or mechanically, so as to serve as a clamping device; the head 64 of this plunger clamps the thread end E behind the funnel-like thread end holding orifice 4. The pressure chamber 61 is connected to a compressed air line 62. A thread clamping means of this kind is particularly desirable when the thread end B has to be held upward. If a thread clamp is used, the stretching of the thread end B by a current of aspirated or compressed air when starting the spinning device is eliminated, since it is held in the stretched condition during the shut-down. A clamping device of this kind can also be used in the apparatus of FIG. 1.

FIG. 3 shows an eccentrically disposed thread end holding orifice 41. Such an arrangement has no effect on the procedure to be followed in shutting down and restarting the spinning device, but it results in constructional advantages in the disposition of the sliver feed tube 51 and in the picking up of thread end E which is stretched substantially in the axial direction in the spinning chamber 2.

Mechanical means can be used instead of pneumatic devices for the stretching of thread end B. In FIGS. 4 and 5 there is shown the manner of operation of a mechanical apparatus of this sort on a spinning device having an upright spinning chamber 2". The twisted yarn F is here drawn out through an outfeed tube 31' which is displaceable in the axial direction. In this spinning chamber arrangement, the tubular chamber arrangement, the tubular stem 21 of spinning chamber 2" serves as the orifice 4' for holding the thread end E. After the infeed system 5 and the outfeed system 3 have been stopped, the thread end E in spinning chamber 2" is stretched by the fact that the yarn outfeed tube 31 is displaced axially all the way into the orifice 4' of the tubular stem 21 of spinning chamber 2", before the spinning chamber 2" itself has stopped. The thread end E, lengthened by the incorporation of the fiber ring R, then lies in the extended state in tube 31' (FIG. 5), for as long as'the spinning device remains stopped, until the spinning chamber 2" is started up again and tube 31 is pulled back into its Working position (FIG. 4) and the thread end E is flung into the gathering trough 24. After that the infeed and outfeed systems are started as already described.

The stretching of the thread end E assures in every case that it will not snarl up and that it will be sufficiently long to reach from the center of the spinning chamber all the Way into the gathering trough when the machine is restarted.

It can happen that the length of the thread end E is not suflicient in all cases, especially when the thread end is to be held outstretched by a thread clamping means disposed behind the thread end holdin orifice. The positive holding of the thread end when the spinning device is shut down is especially advantageous, however, for the achievement of a reliable start-up.

In variation of the above-described procedure, the following procedure is provided according to the invention for this purpose. When the spinning apparatus is to be shut down, first the infeed device 5 and the outfeed device 3 are stopped, while the spinning chamber 2 con tinues to run for a brief period, then coming to a stop. The suction apparatus 42, however, continues to remain in operation, so that the thread end E is sucked from the gathering trough 24 into the orifice 4. In order that the thread end E may be reliably grasped by the clamping means 64, a certain length of thread F is delivered back out of the outfeed tube 31. It is best that only a certain length be returned, so that the thread end E will be grasped by the clamping means 64, but so that it will not be too long for the restarting of the spinning device and thus produce flaws in the yarn. After this back-delivery is completed, the thread end E is gripped by the holding head 64 and is held fast until the spinning device is started up again. The thread end E is thereby held outstretched inside of the spinning device and secured also against external influences such as drafts of air or the unintentional catching and pulling out of thread F.

Upon restarting, the clamp 64 is opened before the infeed system 5 and the outfeed system 3 are started in operation. The released thread end is drawn by the air vortex into the rotating spinning chamber, so that it can come into contact with the fiber ring R which is now being fed again into the gathering trough 24.

In the spinning device according to FIG. 2, the procedure just described can be used in the same manner. In this case, the back-delivery of thread F takes place during the entry of a stream of compressed air into the spinning chamber 2, this stream flowing contrary to the yarn outfeed. The compressed air current passes out of spinning chamber 2' through the thread end holding orifice 4, thereby bringing thread end B into the reach of the clamping means 6.

Clamping the thread end in the orifice 4 also prevents any fraying out of thread end B, in addition to the advantages previously described, thereby preventing thread breakage, for example, when spinning is resumed.

The back-delivery of a certain length of thread can be achieved by various means, as for example by the reversal of the outfeed device 3, or by the formation of a thread reverse between the outlet of the thread outfeed tube 31 and the outfeed rollers 3. In this case, the outfeed rollers are disposed at a correspondingly greater distance from the thread outfeed tube 31 than is represented in the drawings. This, however, is not a subject of the invention and is also unimportant to the method of the invention.

As can be appreciated from the foregoing, the invention essentially provides a sliver spinning method and apparatus whereby air currents are utilized to separate the last-formed thread end B from the fiber supply within the spinning chamber end to reposition such last-formed thread end E into fiber-capturing contact with the fiber supply ring R, so that shut down and resumption of spinning operation can be accomplished without the need for any servicing of the spinning apparatus. The air currents which eifect repositioning of the last-formed thread end E with the fiber ring R are vortex air currents induced by the rotation of the spinning chamber 2, whereas the air currents which efiect separation of the thread end E are basically air currents which flow axially with respect to the rotation axis of the spinning chamber 2. The thread end E separation air currents in general flow from the spun thread discharge end of spinning chamber 2, as for example through the guide tube 31 or the tubular portion 21, and exit the chamber at the opposite end thereof through the passage such as 4, 4', or 41. Such exit passage may be extended through a cover means 11 as in the case of

passages

4 and 41, or may be created within the spinning chamber itself as illustrated by the passage 4' exemplified in FIGS. 4 and 5.

It should be noted that the thread end separation air currents may be produced either by compressed air in troduced through the spun thread delivery end of the spinning chamber 2, as through guide tube 31 in FIG. 2, or can be produced by a suction means communicating with the

opposite end passage

4, 41 as in the case of the embodiments shown in FIGS. 1 and 3.

As can be appreciated by the artisan, the invention is susceptible of numerous modifications and variations to suit the needs of a particular application, such modifications and variations being obvious from the foregoing description of the invention in terms of a limited number of embodiments thereof.

What is claimed is: r

1. In the method of spinning fiber sliver wherein fibers are introduced into a rotating chamber, flung outwardly within said chamber by centrifugal force and become attached at the periphery of said chamber to a twisted fiber thread continually being withdrawn from said chamber through a substantially axially disposed exit and become twisted during such attachment; the improvement in shutting down said spinning which comprises first stopping the feed of fibers to said chamber, stopping the withdrawal means, then stopping rotation of said chamber and then stretching the end of the fiber thread remaining within said chamber in a substantially axial direction; and in restarting said spinning which comprises first starting rotation of said chamber and then starting fiber feeding to said chamber and said withdrawal means.

2. The improved method claimed in claim 1, including providing suction means and including maintaining such suction means in operation during shutdown until after said chamber has stopped rotating; and starting said suction means prior to initiating rotation of said chamber.

3. The improved method claimed in claim 1, including a withdrawal tube means adapted for axial movement and including stretching the end of the thread remaining within said chamber in a substantially axial direction by imparting an axial movement to said withdrawal tube means.

4. The improved method claimed in claim 1, including providing clamping means and including clamping the end of the fiber thread having remained and been stretched in said chamber after said chamber has stopped rotating.

5. The improved method claimed in claim 4, including introducing air under pressure into said chamber from the withdrawal end thereof during shutdown, whereby forcing the end of the fiber thread which is inside said chamber into operative association with said clamping means.

6. Apparatus for spinning fiber slivers, including a rotatable chamber; means adapted to rotate said chamber; a housing surrounding said chamber; fiber feeding means to said chamber; means to feed fibers into said chamber; means adapted to produce an underpressure in said chamber; a withdrawal orifice opening into said chamber; means adapted to withdraw a thread through said withdrawal orifice; a hole opening into said chamber opposite said withdrawal orifice serving as an air passageway.

7. Apparatus as claimed in claim 6, including means adapted to bring and keep the end of the thread which is inside said chamber into substantial axial alignment in said chamber upon stoppage of said apparatus.

8. Apparatus as claimed in claim 6, wherein said hole is adapted to receive the thread end remaining in said chamber upon stoppage of said apparatus.

9. Apparatus as claimed in claim 6, wherein said hole is operatively associated with air streamproducing means which air stream leaves said chamber through said hole.

10. Apparatus as claimed in claim 9, wherein said air stream producing means is an underpressure producing means.

11. Apparatus as claimed in claim 10, wherein said passage has a flared entrance portion thereof communicating with said chamber.

12. Apparatus as claimed in claim 6, including a hollow axial shaft means serving as said withdrawal orifice opening into said chamber and a cover means on said housing containing said hole opposite to said withdrawal orifice.

13. Apparatus as claimed in claim 12, wherein said hole in said cover means is disposed in eccentric relation to the axis of rotation of said chamber and wherein said hole is operatively associated with air stream producing means.

14. Apparatus as claimed in claim 6, including a hollow axial shaft means serving as said hole and being operatively associated with air stream producing means and a cover means containing said withdrawal orifice and concentric relation to the axis of said chamber.

15. Apparatus as claimed in claim 14, including a tube means in said cover means in concentric relation which tube means is adapted for axial movement until in said hollow axial shaft means.

16. Apparatus as claimed in claim 6, including means for introducing compressed air through the fiber exit from said chamber.

17. Apparatus as claimed in claim 6, including clamping means operatively associated with said orifice and adapted to clamp said sliver thread end.

18. Apparatus as claimed in claim 17, including clamping means which is pneumatically operable.

19. Apparatus as claimed in claim 17, wherein said clamping means includes a member disposed for movement relative to said cover means along a path extending into said hole and adapted to clamp the thread end received in said hole against the wall thereof.

20. Apparatus for spinning fiber slivers, including a rotatable chamber with a hollow axial shaft means; means adapted to rotate said chamber; a housing surrounding said chamber and supporting said chamber by means of said hollow axial shaft means; a cover means on said housing opposite to said axial shaft means and containing a hole in concentric relation to the axis of rotation of said chamber; fiber feeding means to said chamber; means to feed fibers into said chamber; means to produce an underpressure in said chamber; a tube means in said hollow axial shaft means containing a withdrawal orifice opening into said chamber; means adapted to withdraw a thread through said withdrawal orifice; means to selectively impart an axial movement to said tube means.

21. Apparatus as claimed in claim 20, wherein said movable tube means is adapted to clamp said thread end against the wall of said hole in said cover means.

22. Apparatus for spinning fiber slivers, including a rotatable chamber with a hollow axial shaft means; means adapted to rotate said chamber; a housing surrounding said chamber; a cover means on said chamber; fiber feeding means to said chamber; means to feed fibers into said chamber; a withdrawal orifice opening into said chamber; means adapted to withdraw a thread through said withdrawal orifice; a hole opening into said chamber 9 opposite said withdrawal orifice which is operatively associated to means adapted to produce an underpressure in said chamber; a back-delivery mechanism adapted to return a certain length of thread through said withdrawal orifice in said chamber.

References Cited UNITED STATES PATENTS 3,115,001 12/1963 Cizek et a1. 5758.91 3,121,306 2/1964 Cizek et a1. 5758.89 3,132,465 5/1964 Putnam 5758.89

Schlosser 57--58.95 Mikulecky et a1. 57-34 Cizek et a1. 57-78 Cizek et a1. 57-81 Elias et a1 5758.95

US. Cl. X.R.