US3665976A

US3665976A - Suction apparatus on a textile machine

Info

Publication number: US3665976A
Application number: US50722A
Authority: US
Inventors: Alexis Freihofer
Original assignee: Maschinenfabrik Rueti AG
Current assignee: Ruti Machinery Works Ltd; Maschinenfabrik Rueti AG
Priority date: 1969-07-22
Filing date: 1970-06-29
Publication date: 1972-05-30
Anticipated expiration: 1989-05-30
Also published as: BE753693A; CS190315B2; DE1942212B2; GB1296475A; FR2055233A5; CH502459A; JPS4824427B1; DE1942212A1

Abstract

A suction apparatus for picking up the free end-portion of a thread on a textile machine wherein the thread is brought into a freely stretched condition over a suction means and is drawn into this means by a suction action, said apparatus comprising a thread-holder located on the suction means, said holder comprising clamping zones that are biassed towards each other for clamping a thread therebetween and guide means for guiding the end-portion of the thread towards the clamping zones; and means for pulling the end-portion of the thread, drawn into the suction means, in between the clamping zones.

Description

O United States Patent 1151 3,665,976 Freihofer 45 May 30, 1972 [54] SUCTION APPARATUS ON A TEXTILE [56] References Cited MACHINE UNITED STATES PATENTS 1 lnvemofl Alexis Frelhofer, Rmi/ZH, Switzerland 2,956,593 /1960 Baumann ..139/247 3,233,636 2/1966 Bulcock ....l39/256 [73 1 Ass'gnee' :i: g g wwks Run/2H 3,417,793 12/1968 Freihofer.... 1 39 194 Ze 3,494,151 2 1970 Baker et al ..66/140 s [22] Filed: June 29, 1970 Primary Examiner-Henry S. Jaudon PP 50,722 Attorney-Donald D. Denton Foreign Application Priority Data [57] ABSTRACT A suction apparatus for picking up the free end-portion of a July 22, 1969 Switzerland ..01 l 162 thread on a textile machine wherein the thread is brought into a freely stretched condition over a suction means and is drawn [521' US. Cl ..l39/ 126 i hi means b a suction action, said apparatus comprising [51] Int. Cl. ..D03d 47/24 a thread-holder located on the suction means, said holder [58] Field of Search ..l39/122, 125, 126, 246, 247, comprising clamping zones that are biassed towards each 139/256 R, 256 A; 194, 257; 242/ 35.6 E; 66/ 140 S, other for clamping a thread therebetween and guide means for 145 S guiding the end-portion of the thread towards the clamping zones; and means for pulling the end-portion of the thread, drawn into the suction means, in between the clamping zones.

17 Claims, 5 Drawing Figures mnm-lgim Patented May 30, 1972 3,665,976

5 Sheets-Sheet 2 Patented May 30, 1972 5 Sheets-Sheet 5 Fig.4

lllllll'l SUCTION APPARATUS ON A TEXTILE MACHINE BACKGROUND OF THE INVENTION This invention relates to an apparatus on a textile machine, e.g., a loom, for picking up the loose end-portion of a thread, which is moved in a freely extended condition over a suction means of the apparatus and is drawn into the suction means by the suction of said means.

This type of thread operation takes place for example during weaving when the loose end of a weft-thread is released from a shuttle after the passage of the shuttle through a shed and the loose end is transferred to a suction means in the form of a nozzle. After this transfer, the weft-thread is often withdrawn somewhat prior to beating up at the beat-up of the fabric so that it is in a neatly stretched position for the beat-up. Since it is desirable to keep the thread-ends drawn in by the suction nozzle as short as possible, it is found that when the thread is pulled back for the purpose of bringing it into a stretched condition, the thread is not retained in the suctionnozzle with the necessary reliability and firmness. This is observed in particular when threads of different kinds are used.

Advantageously, this invention provides an apparatus for overcoming this draw-back. Thus, the present invention provides a suction apparatus or suction-nozzle arrangement, having additional means for retaining the thread which are extremely reliable even when different kinds of thread are being handled.

For the purpose of pulling off the end-tum portion of a thread from a bobbin in the automatic changing of bobbins, it is known to provide a suction-nozzle which is covered by a flap when the end-tum is located in the interior of the suctionnozzle. In this arrangement, the flap acts as a clamp or brake for the thread. On account of the flap being adapted to move over the suction-nozzle and away from it again, this known arrangement is suitable only for certain applications, in particular the afore-mentioned pulling off of the end-tum. This arrangement cannot, however, be used for taking over the end of the thread from a moving shuttle or the like.

This invention contemplates a suction apparatus which is characterized in that a thread-holder means is positioned on a suction means, the thread-holder means comprises clamping zones that are biassed towards each other and are used to clamp a thread, guides are provided for guiding the end-portion of the thread towards the clamping zones, and means are provided for the purpose of drawing the end-portion of the thread, sucked into the suction-nozzle, in between the clamping zones.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail by reference to its specific embodiments and to the accompanying drawing, in which:

FIG. 1 is a schematic illustration of a loom having means for inserting weft-threads, wherein use is made of the suction apparatus of the present invention;

FIG. 2 is an end view of a suction-nozzle in the apparatus of the invention used as seen in the longitudinal direction of its suction orifice;

FIG. 3 is a side view of the nozzle shown in FIG. 2 as viewed on the narrow side in the direction of the arrow III;

FIG. 4 is a view of another embodiment of the suction-nozzle arrangement of the invention wherein an auxiliary suctionnozzle is employed; and

FIG. 5 is a detail side-view, on a larger scale, of the end of the auxiliary suction-nozzle seen in FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 illustrates schematically an embodiment of a weft-insertion means in a loom, the suction-nozzle arrangement of the present invention being used with this means. The reference numerals l1 and 12 indicate large weft-thread supply bobbins arranged on both sides of the frame of the loom. From these bobbins the

threads

13 and 14, respectively,

run through the

rings

15 and 16, the thread-

braking devices

17 and 18 and additional thread guides 19 and 20 (all of which elements are secured to the frame of the loom.) In FIG. 1, the thread 13 terminates in the suction-novJe or retaining nonle 21, which constitutes a thread-retaining means, whereas the thread 14 passes along the corresponding suction-nozzle or retaining nozzle 22, which also constitutes a thread-retaining means, and through the pull-

back arrangement

48, 49. The retaining suction-

nozzles

21 and 22 are mounted on the frame of the loom. To make the drawing easier to understand, only the warp-threads 23 at the sides of the fabric are shown, and not the entire group. The thread 14 extends through the shed formed by the warp-threads 23, and its free end is retained by the suction-nozzle 25. The suction-nozzle on the left-hand side which corresponds to nozzle 25 is indicated by the reference numeral 26. The

nozzles

25 and 26 are arranged on the movable sley 30 and move relatively thereto in a direction at rightangles thereto (forwards and backwards as shown by the dashdot lines). Located on the sley 30 is the shuttle 31 used as a thread positioning or locating element or means for inserting the weft-threads into the shed. The shuttle 31 incorporates an element made of ferromagnetic material, e.g. iron, which element is positioned into the lower slide surface of the shuttle. The shuttle also contains two

horizontal orifices

43 and 44 extending laterally therethrough. Means for retaining the weft-thread during its insertion into the shed are provided in these orifices. These means can, for example, comprise bristles which are able to retain a thread disposed therein by applying a predetermined force to the thread. It is possible nevertheless to withdraw the thread from the shuttle 31, i.e. the predetermined force is less than the breaking strength of the weft-thread (i.e. threads 13 and 14).

The reed 32 is secured to the sley 30. Furthermore, in the sley there are provided

magnetic control arrangements

33 and 34, the electrical properties of which can be varied by a ferromagnetic material. In the present embodiment, each of the

arrangements

33 and 34 comprises a permanent magnet surrounded by a wire coil. These magnets are U-shape (i.e. they are horse-shoe magnets) and are incorporated in the sley 30 in such a manner that their poles are upwardly directed, (i.e. the magnet forms an upright U). The ferromagnetic element 35, which moves with the shuttle, produces a change in the magnetic flux in the

magnetic arrangements

33 and 34. Thus, when the shuttle 31 with the ferromagnetic material 35 fitted at its underside, moves over the

arrangements

33 and 34, a voltage variation in the coils is produced.

On both sides of the loom there are also provided pull-in

devices

36 and 37 incorporating, respectively, the

hooks

41 and 42. These devices are adapted to rotate about the

spindles

38 and 39 carried by the sley 30, and are used for pulling the weft-threads l3 and 14, respectively, into the shuttle 31. This pull-in action takes place when, during the movement of the sley into the foremost position, i.e. the thread beat-up position, each of the rollers on the two sides (indicated by the same reference numeral 27) moves over the projecting portion 28 of a carnmed surface and thereby swings the hook 41 about the spindle 38 in the anti-clockwise direction, and the hook 42 about the" spindle 39 in the clockwise direction. The thread-

guides

19 and 20 are controlled in such manner that they only pass the thread that they hold to the

hooks

41 and 42, respectively, when the shuttle 31 is located at their side of the loom. The reference numerals 45 and indicate two pairs of shears for cutting off the weft-

threads

13 and 14, respectively. The thread-

braking devices

17 and 18 each incorporate a thread-

clamp

46 and 47, and these clamps are each actuated by a controllable magnet. Finally, a thread pullback means including

elements

48 and 49, is provided on each side of the loom.

In the phase of operations shown in FIG. 1, the shuttle 31 has just arrived from the left at the right-hand side of the loom. The thread 14, inserted by the shuttle during its flight, has been braked by the clamp 47 of the braking device 18 and thus pulled out of the shuttle 31 after the shuttle has moved over the magnetic arrangement 33 and the magnet of the braking device 18 has been supplied with current so as to close this device. The supply of current to the magnet of the device 18 was controlled by a signal which was produced by the ferromagnetic element 35 during the flight of the shuttle 31 over the arrangement 33. As shown in FIG. 1, the pulled out end of the thread 14 has been drawn in and retained by the nozzle 25. During this entire operation, the magnet of the braking device 17 on the right-hand side has been supplied with sufiicient current to cause closing of the clamp 46.

In the course of further operation of the loom, the thread pull-back means (48 and 49) on the left-hand side of the loom pulls back the thread 14 a little by means of the hook 48 so that the thread is neatly stretched when the reed 32 beats up the pulled-in thread 14. The shed comprising the warp-threads 23 is then changed. The

shears

45 and 40 cut off the weftthread 14 at the two edges of the fabric. At this moment the suction-nozzle 26 is not at the same level as the fabric beat-up zone, but is moved forward away from this zone and therefore also away from the thread 14, i.e. away from the sley 30. The end of thread that becomes free on the left-hand side when cutting takes place is therefore drawn into the retaining nozzle 22. The short thread-end hanging in the thread-transfer nozzle 25 must be drawn away.

In the foremost position of the sley 30, the pull-in hook 41 rotates in the counter-clockwise direction and is moved through the horizontal orifice 44 into the shuttle 31. When the sley 30 moves back again, the hook picks up the thread 13, presented by the thread-guide 19, and, since the clamp 46 is closed, draws the thread out of the thread-retaining means provided by nozzle 21 and pulls it as a loop through the orifice 44 in the shuttle 31. The movement of the pull-in device 37 that occurs at the same time is not important, since this cannot transfer a thread through the thread-guide 20. When the shuttle 31 is shot to the left immediately thereafter, the weftthread 13 is held by a weft-retaining means contained in the orifice 44 and, since the clamp 46 opens at this moment, the thread is drawn off from the supply bobbin 11 and introduced into the shed. An operation similar to that just described is then repeated, but on the other side of the loom.

As already mentioned, the suction-

nozzles

25 and 26, constituting the thread transfer devices or means, are carried by the sley 30 and are also movable at right-angles to the longitudinal direction of the sley. Thus, as the shuttle 31 moves through the loom and past the suction-

nozzle

25 or 26, these nozzles can be moved relatively to the sley 30 into a position such that the fabric-side or forward side surface of the shuttle 31 moves directly past the orifice of the suction-

nozzle

25 or 26. The end of the thread drawn out of the shuttle 31 is thus picked up in a reliable manner. Additionally, the

nozzles

25 and 26 can be moved away from the weft-

threads

13 and 14 when these threads, as described above, are taken over by the retaining

nozzles

21 and 22 after they have been cut off.

When the weft-thread 14 is pulled back by means of the lefthand hook 48, part of the thread drawn into the suction-nozzle 25 is pulled out of it again. Since the losses of thread should be kept as low as possible, care is taken to see that the thread-end remaining in the nozzle 25 is as short as possible. The suction applied by the nozzle 25 to the thread 14 therefore becomes relatively small. It can be so small that the thread 14 can jump out of the nozzle 25.

To prevent this, and in accordance with the present invention, the nozzle 25 (and the nozzle 26) can be constructed, for example, in the manner seen in FIGS. 2 and 3. These figures are on a greater scale.

The end of nozzle body 50 forms an orifice or opening 51 and has at the top a small plate 52 and a small plate 53. The plate 53 is bonded or otherwise secured to the noule body 50. The plate 52 is attached to the carrier 54 by screws 58 and is supported by said carrier. The carrier 54 is in turn secured to the nozzle body 50 by screws 55. The boundary or edge portion 62 of plate 52 and the boundary or edge portion 63 of plate 53 cross at the point of intersection 60. They form an acute angle with each other and each one constitutes a guide for the

thread

13 or 14.

The plate 52 is made of ferromagnetic material and is continuously pulled by the magnet 56 which is inserted in the nozzle body 50. This results in a zone (located on the right-hand side of the point of intersection 60 in FIG. 2) in which portions of the

plates

52 and 53 bear against each other and are constantly biassed towards each other to provide a thread holding means, or thread holder device. This zone is bounded by the solid line 66 defining the lower edge of plate 52 and the broken line 67 defining the upper portion of plate 53. Since the thread to be drawn into the suction nozzle 25 is guided by the

boundary portions

62 and 63 towards the point of intersection 60, these

boundary portions

62 and 63 form guide arms or surfaces which diverge from each other beginning at the area where the

plates

52 and 53 bear against each other. By pressing on the area 57, indicated in FIG. 2 by the broken line, the plate 52 can be tilted about the edgeportion 59, so that the zone of the plate 52 which bears on the plate 53 is lifted somewhat from the plate 53 thereby overcoming the bias provided by the magnet 56. This results in the release of the end portion of thread held between these

plates

52 and 53 and this end portion can be drawn into the nozzle opening 51 by the flow of air.

In order to take over the end of a thread inserted by the shuttle 31, a nozzle 25 as already mentioned, is brought into the direct vicinity of the forward side-wall of the shuttle 31 when the shuttle 30 moves from left to right. By means of the clamp 47, the weft-thread 14 is retained at an appropriate moment. This is so selected that the thread-end, drawn from the shuttle 31 or located thereby so it, extends over the greater part of the nozzle opening 51 or even slightly beyond the nozzle 25 before it is drawn into the nozzle. Since FIG. 2 shows a view of the nozzle 25 in the direction of its opening, the thread-end, indicated by the reference numeral 64, extends in this Figure from right to left. Immediately after the thread 14 has been drawn out of the shuttle 31, and before it is drawn into the nozzle 25, it stretches out in front of the noule 25 for a short moment in a straight line i.e. parallel with a straight line which lies within the acute angle formed by the

boundary portions

62 and 63 and which runs through the point of intersection 60. When the end-portion 64 of the thread is drawn into the nozzle opening 51, the

boundary portions

62 and 63 act as guides for the end-portion 14 of the thread and guide it to the point of intersection 60. It then passes downwards from the point of intersection 60.

The thread is thereupon drawn back a little through the pull-back device of

means

48, 49 shown on the left in FIG. 1, by this device moving in the direction of the arrow 61 shown in FIG. 1 and into the position as shown in this Figure. Thus, the thread 14 is stretched out neatly in the shed. At the same time part of the length of the thread-end 64 is again drawn out of the opening 51. During this operation, the thread-portion 64 slides between the contiguous zones of the

plates

52 and 53, defined by the boundary or

edge portions

66 and 67, and moves into the position indicated by the numeral 64 in FIGS. 2 and 3, in which position it is clamped therebetween as a result of the bias imposed by the magnet 56.

It will be recognized that the weft-thread is retained in a very reliable manner by the suction arrangement illustrated. The retaining force resulting from the clamping action is independent of the length of the thread-end 64 and is considerably greater than the force resulting from the suction effect. In particular this greater retaining force is also present when different kinds of weft material are being worked.

If the weft-thread is elastically extensible, it is hardly possible, without the provision of the clamping zones of this invention to prevent the end-portion of the thread from springing back and jumping out of the nozzle after it has been released from the shuttle. Here it is of particular advantage that as a result of a pull on the thread this is moved into and between the clamping zones, so that simply because of its elastic contraction it is moved in between the clamping zones. A

pullback arrangement

48, 49 is not absolutely necessary in these circumstances.

If the

boundary portions

62 and 63, acting as guide-arms or guide means, form anacute angle with each other, the size of which corresponds approximately to that shown in FIG. 2, slip of the thread-end 64 is reliably ensured between the zones of mutual contact defined by the

boundary portions

66 and 67, i.e. between the superposed zones of the

plates

52 and 53. In order to provide a wider safety margin for slip-through, one or both of the boundary portions can be bent immediately in front of the point of intersection 60 in a direction such that the angle at said point of intersection 60 becomes still more acute. This is the case with the boundary portion 63 seen in FIG. 2.

After the weft has been beaten up, the weft-thread 14 is cut on both sides of the loom by the shears and 45. The resultant free end is drawn into the retaining nozzle 22 on the left-hand side of the loom. On the right-hand side of the loom, the cut-off thread-end remains firmly held in the suction-n02 zle 25.

If, as in the embodiment in question, the suction apparatus or arrangement operates on a continuous basis, then for the apparatus to operate correctly, i.e. for the next thread-end to be properly picked up, it is necessary that each clamped thread-end is removed again before the new thread-end is picked up.

Therefore, when, during the further course of the operation of the loom, the sley is moved backwards, the apparatus strikes a spring-loaded pin 65 in the rearmost position of its zone 57. This causes the

plates

52 and 53 to be moved apart somewhat in the zones defined by

portions

66 and 67 where they bear against each other. In this condition, the thread-end 64, held by the nozzle 25, is drawn into said nozzle.

A method of removing the thread-end 64 held in the nozzle 25, based on a somewhat different mode of operation, will be explained by reference to the embodiment shown in FIGS. 4 and 5. FIG. 4 shows the right-hand side of the loom together with the warp-threads 23, the sley 30 and the magnetic control arrangement or electrical sensing means 33. The suction-nozzle 25, the weft-thread pull-back device or means 48 and 49,

and the retaining nozzle 21 are again of the same construction as that already described. This also applies as regards the cutting means 45, but with the difference that this cutting means, in contrast to that shown in the embodiment of FIG. 1, makes a cut only after each second weft-insertion. Between the suction-nozzle 25 and the shed formed by the warpthreads 23, there is provided another suction means in the form of a second suction-nozzle or auxiliary suction-nozzle 70. That side of this nozzle facing the suction-nozzle 25 incorporates a threader means, which is formed by appropriately shaping the wall of the nozzle. The nozzle 70 is mounted on the frame of the loom. The shape of this threader means 71 is shown in side-view in FIG. 5.

After the nozzle 25 has drawn in the end-portion 64 of the thread 14 from the shuttle 31, and the thread 14 has been pulled back by the pull-

back device

48 and 49 located on the left-hand side of the loom, so that the thread is firmly held in the nozzle 25, the nozzle 25 moves farther forward, ie in the direction of the arrow 61. The end-portion 64 of the thread is thereby also drawn forward as shown in FIG. 4. This end-portion 64 of the thread slides along the

curve portions

72 or 73 of the threader and passes into the cut-away zone 74. When, thereupon the nozzle 25 moves to the rear again, a pulling force occurs on the thread-portion 64 between the thread 14, now beaten-up and woven into the fabric, and the nozzle 25, since the nozzle 70 remains stationary and the end-portion of the thread is retained in the cut-away portion 74. Therefore, despite the fact that it is clamped between the

plates

52 and 53, the end-portion 64 of the thread is pulled out of these plates and out of the nozzle 25. As soon as the thread is free of the noule 25, it is drawn completely into the nozzle 70. After the next weft-thread 13 is inserted into the shed, the weftthread 13 and the thread-end drawn into the nozzle 70 are simultaneously cut. The cut thread-end 64 drawn into the nozzle 70 is thus removed therethrough.

When removing the end-portion 64 of the thread by the method described by reference to FIG. 1 and in which the plate 52 is lifted somewhat from plate 53 due to striking the pin 65, it can occasionally happen that the thread-portion 64 remains hanging. In such circumstances the next end-portion of thread to be picked up is held with too little retaining force or is not held at all. If, in addition, the weft-threads are inspected in the interior of the nozzle 25, the hanging end-portion of thread gives the incorrect impression that a weft-thread is present. These disadvantages are eliminated by the method of and apparatus for removing the end-portions 64 of thread described in reference to FIGS. 4 and 5.

What is claimed is:

1. In a suction apparatus having suction means for picking up a free end-portion of a thread on a textile machine wherein the thread is brought by thread locating means over said suction means and is drawn into said suction means by the suction action thereof, the improvement which comprises:

a thread-holder located on the suction means, said threadholder comprising clamping zones that are biassed towards each other for clamping a thread therebetween; guide means for guiding the end-portion of the thread towards the said clamping zones; and means for pulling the end-portion of the thread, drawn into the suction means, into clamped condition positioned between the said clamping zones.

2. The suction apparatus of claim 1 in which said suction means comprises a suction nozzle having a suction orifice, the clamping zones are formed by two small clamping plates which bear against each other, said plates being located at the suction orifice of the suction-nozzle and being biassed towards each other, said guide means comprises a pair of generally opposed guide surfaces which, beginning at the clamping zones, diverge from each other to form an opening therebetween; the end-portion of thread to be picked up extends over the suction orifice in the freely stretched condition from that side on which the clamping zones are located, and is moved in between the clamping zones by being pulled back by said means for pulling the thread.

3. The suction apparatus of claim 2 in which said textile machine is a loom, and said means for pulling said thread comprises a thread pull-back device; the thread pull-back device and the suction-nozzle being located on opposite sides of the warp-threads on said loom.

4. The suction apparatus of claim 3 in which the thread pullback device is arranged between a retaining means for holding the thread and the suction-nozzle.

5. The suction apparatus of claim 2 in which the clamping plates are arranged approximately in a plane at right-angles to the direction in which suction takes place and are positioned to partly overlap each other, said overlapping portions of the 1 plates forming said clamping zones, the lateral boundary portions of each of the two plates cross at a point of intersection, and said boundary portions comprise the guide means which extend in one direction from the point of intersection and form the limits of the clamping zones which extend in the other direction from the point of intersection.

6. The suction apparatus of claim 5 in which the two plates are each secured on opposite sides of the suction-noule.

7. The suction apparatus of claim 5 in which the upper plate of the two clamping plates has lateral boundary portions that are rectilinear on both sides of the point of intersection and the lower plate of the two clamping plates has lateral boundary portions that have a change of course in the direction extending from the point of intersection in the sense of an increase of the angle defined by the guide surfaces, and in the other direction extending from the point of intersection, the first boundary portion of said lower plate extends in at least approximately the same direction and then angles at right-angles thereto, to form a limit for one of the clamping zones.

8. The suction apparatus of claim 5 in which the upper plate comprises ferromagnetic material and is biassed towards the lower plate by a magnetic means.

9. The suction apparatus of claim 2 in which the said guide surfaces are provided by generally inward directed edges of said clamping plates to form an acute angle therebetween so the end-portion of the said thread can be extended over the suction-nozzle in the freely stretched condition in a direction which is at least approximately parallel with a straight line which falls within the said angle formed by the guide surfaces of said guide means and pass through the apex of this angle.

10. The suction apparatus of claim 2 in which said nozzle has an elongated suction orifice and the clamping zones are located adjacent to the suction orifice at one end of its lengthwise extent.

1 1. The suction apparatus of claim 2 in which the divergent guide surfaces form an acute angle.

12. The suction apparatus of claim 1 in which additional means are provided for individually removing from said thread-holder the end-portions of thread clamped in said holder.

13. The suction apparatus of claim 12 in which said threadholder includes means for biassing the clamping zones toward each other, and said additional means comprises a device for cutting ofi the free end-portion of each thread and for opening the two clamping zones thereby overcoming the effect of said biassing means.

14. The suction apparatus of claim 12 in which said additional means comprises an auxiliary suction-nozzle which, for the purpose of picking up a thread, is provided with threader means, said suction means comprises a first suction-nozzle,

and the first and the auxiliary suction-nozzles are adapted for movement relatively to each other so that a first such relative movement can effect bringing of the thread into the threader means and a second such relative movement can effect pulling of the thread out of the first suction-noule, with the said second relative movement also effective for causing an increase in the length of thread required up to the first suctionnoule.

15. The suction apparatus of claim 14 in which the auxiliary suction-nozzle is located at a side of the first suction-nozzle that is adapted to have extended therefrom the end-portion of thread to be picked up, and the threader means is formed by a portion of the side-wall of the said auxiliary suction-noule that is adjacent to the said first suction-nozzle.

16. The suction apparatus of claim 14 in which said textile machine is a loom having a sley and means for forming a shed from warp threads supplied to the loom, and, in a lateral direction thereof and in the direction away from the shed. there is first arranged said auxiliary suction-nozzle followed by the said first suction-nozzle, the auxiliary suction-nonle being mounted firmly on the loom and the first suction-noule adapted to be movable on the sley.

17. The suction apparatus of claim 2 in which, immediately before the clamping zones and extending towards said zones the angle defined by the said diverging guide surfaces is diminished by a change in direction of at least one of the said guide surfaces.

Claims

1. In a suction apparatus having suction means for picking up a free end-portion of a thread on a textile machine wherein the thread is brought by thread locating means over said suction means and is drawn into said suction means by the suction action thereof, the improvement which comprises: a thread-holder located on the suction means, said thread-holder comprising clamping zones that are biassed towards each other for clamping a thread therebetween; guide means for guiding the end-portion of the thread towards the said clamping zones; and means for pulling the end-portion of the thread, drawn into the suction means, into clamped condition positioned between the said clamping zones.

4. The suction apparatus of claim 3 in which the thread pull-back device is arranged between a retaining means for holding the thread and the suction-nozzle.

5. The suction apparatus of claim 2 in which the clamping plates are arranged approximately in a plane at right-angles to the direction in which suction takes place and are positioned to partly overlap each other, said overlapping portions of the plates forming said clamping zones, the lateral boundary portions of each of the two plates cross at a point of intersection, and said boundary portions comprise the guide means which extend in one direction from the point of intersection and form the limits of the clamping zones which extend in the other direction from the point of intersection.

6. The suction apparatus of claim 5 in which the two plates are each secured on opposite sides of the suction-nozzle.

11. The suction apparatus of claim 2 in which the divergent guide surfaces form an acute angle.

13. The suction apparatus of claim 12 in which said thread-holder includes means for biassing the clamping zones toward each other, and said additional means comprises a device for cutting off the free end-portion of each thread and for opening the two clamping zones thereby overcoming the effect of said biassing means.

14. The suction apparatus of claim 12 in which said additional means comprises an auxiliary suction-nozzle which, for the purpose of pIcking up a thread, is provided with threader means, said suction means comprises a first suction-nozzle, and the first and the auxiliary suction-nozzles are adapted for movement relatively to each other so that a first such relative movement can effect bringing of the thread into the threader means and a second such relative movement can effect pulling of the thread out of the first suction-nozzle, with the said second relative movement also effective for causing an increase in the length of thread required up to the first suction-nozzle.

15. The suction apparatus of claim 14 in which the auxiliary suction-nozzle is located at a side of the first suction-nozzle that is adapted to have extended therefrom the end-portion of thread to be picked up, and the threader means is formed by a portion of the side-wall of the said auxiliary suction-nozzle that is adjacent to the said first suction-nozzle.

16. The suction apparatus of claim 14 in which said textile machine is a loom having a sley and means for forming a shed from warp threads supplied to the loom, and, in a lateral direction thereof and in the direction away from the shed, there is first arranged said auxiliary suction-nozzle followed by the said first suction-nozzle, the auxiliary suction-nozzle being mounted firmly on the loom and the first suction-nozzle adapted to be movable on the sley.