EP0635590B1 - Double-apron drafting device - Google Patents

Description

The invention relates to a double apron drafting system for spinning machines with a fiber bundling zone that corresponds to the Output roller pair of the main drafting field connects and the the pair of delivery rollers follows. With this known drafting system (DE-A1-41 39 067) is one in the fiber bundling zone Output roller pair arranged running further pair of straps, the fiber assembly emerging from the pair of output rollers leads directly into the pair of delivery rollers and its lower apron over the lower rollers of the pair of output rollers as the delivery roller pair is also running. The top roller of the pair of delivery rollers has suction openings arranged in a ring. In this way, more should be done than known drafting systems Fibers are bundled and compacted so that in the pair of delivery rollers almost all fibers combined and compressed are so that there is no so-called spinning triangle.

It has been shown that this device is only partially works satisfactorily. Because the pair of output rollers is strapped on both sides with very high Pressures are applied to a proper draft clamping point to reach. Again, this is for the high speed running strappy disadvantage because of this exposed to high wear and tear are. But also the bundling and bundling of the fibers is poor. It was found that through the double apron guide from the pair of exit rollers emerging sliver a summary and bundling only immediately in the entry nip of the delivery roller pair the suction zone of the top roller of the pair of delivery rollers takes place. There the fibers are strongly redirected in this combination, follow this redirection only partially, which is incomplete Bundling causes. In addition, the known Device by extending the bottom strap over the Output roller and delivery roller no tension delay possible.

From DE-39 27 936 C1 it is known to be a fully warped Sliver following the draft in a fiber bundling zone summarize. There is one at the drafting system exit Deflection path provided by the lower exit roller is formed. In the area between the nip and the subsequent pressure roller, also with this exit roller cooperates, the exit roller is with a Provide suction zone for the stretched fiber sliver, in the Area a blowing device with a flow component is arranged transversely to the suction zone. The fiber bundling takes place through this blow air flow, while the suction zone is just the job has to move the blown air away. It has shown, that both the deflection and the blowing air have a negative Influence the fibers in the combination, so that the desired better yarn values are not achieved.

The object of the present invention is to overcome these disadvantages of To avoid the state of the art and both the delay and also improve the bundling so that no spinning triangle arises, but also not the fibers in the summary to be confused.

This object is achieved according to the features of claims 1 and 6. The suction air flow only takes about the width of the desired one Summary one, creating a cross flow on the fiber structure (FB) acts as long as it is wider than the suction air flow is. Because the fiber structure (FB) on a largely flat transport surface only one suction air flow exposed, the fibers can move freely in their parallel position can be summarized without confusing them. It It has been shown that this is a very good compression of fibers is reached, so that no spinning triangle at Outfeed from the pair of delivery rollers arises and the yarn values, but also significantly improved the spinning speed become.

During the summary of the fiber structure, the ratio the peripheral speed of the pair of output rollers and Delivery roller pair adapted to the crimp of the fiber material. If the fiber material is under too much tension, then summarizing the fibers affects. On the other hand, must the tension required for the transport speed be present to ensure proper transport of the fiber structure to ensure.

The suction device is expediently above the means of transport arranged above the sliver so that from the room below of the fiber structure is sucked in air. This will simple construction and easy access to the drafting system reached, so that the apron exchange without further Assembly is possible.

The compression device expediently has a Delivery roller led perforated straps on itself parallel to the fiber structure right up to the pair of exit rollers extends. With this arrangement, the pair of output rollers becomes emerging fiber structure immediately taken over and summarized, but at the same time by the straps guided. The strap has been arranged in the center of the running direction Breakthroughs on the summary of the fiber structure determine to a fiber ribbon. Therefore, it becomes useful the size of the perforation depending on the spun Thread number selected. The adjustability of the strappy in its Height to the pair of exit rollers allows a change the distance to the pair of output rollers. It is useful for this a height-adjustable support is provided.

To pinch the fibers between the top strap and the Avoid pressure roller in the area of the spinning triangle and thus to improve the integration of the fibers is the Strappy tension adjustable so that there is a detachment of the Strappy comes from the pressure roller in the exit area. Alternatively However, this can also be done by the straps wrapped delivery roller has a free space in shape a groove so that fibers sucked in through the perforation do not get caught between the roller surface and the apron can.

Through DE-AS 1 039 422, a drafting system for pulling up is indeed a nonwoven fabric known on a spinning machine, which has a compression part with a perforated belt having. However, as the strappy strap with considerable lower speed than the one upstream of the belt Separating roller runs, this is about a fiber collecting surface on which the through the singling roller isolated fibers collected into a fuse become. There is a compression in the direction of transport, while in the subject of the invention one from the pair of output rollers finished double apron drafting Fuse is compressed transversely to the transport direction. The well-known The device has both its structure and its mode of operation not comparable to the subject of the application.

Fig. 1:

den Aufbau des erfindungsgemäßen Streckwerkes schematisch im Querschnitt,

Fig. 2:

eine Draufsicht auf die Transportebene aus der Richtung unterhalb der Streckwerkszylinder,

Fig. 3:

die Verdichtungseinheit im Detail,

Fig. 4:

eine weitere Einzelheit in perspektivischer Ansicht,

Fig. 5:

eine andere Ausführung des erfindungsgemäßen Streckwerkes.

Further details of the invention are described with reference to the figures. Show it:

Fig. 1:

the structure of the drafting system according to the invention schematically in cross section,

Fig. 2:

a plan view of the transport plane from the direction below the drafting cylinders,

Fig. 3:

the compression unit in detail,

Fig. 4:

another detail in perspective view,

Fig. 5:

another embodiment of the drafting system according to the invention.

The double apron drafting system usually consists of the first pair of rollers 1 and 1 ', which the fiber sliver FB through a compressor 10 is supplied. Between the first pair of rollers 1 and 1 'and the second pair of rollers 2 experience this Sliver an advance. Before entering the second The pair of rollers 2, 2 'becomes the fiber sliver by a further compressor 11 summarized. Between the second pair of rollers 2, 2 'and the output roller pair 3 and 3', the main distortion occurs, in which the sliver is led through the straps 4 and 4 ' become. The top strap 4 is in the usual way by a Strappy cage 41 stretched while the lower strappy 4 'over a rail 42 runs, which at the same time to support the Oberriemchens serves. The delay is at the pair of output rollers 3, 3 ' of the sliver ended. Between the pair of exit rollers 3, 3 'and the delivery roller pair 5, 5' closes a fiber bundling zone in which the from the pair of output rollers emerging fully warped fiber bundle FB transverse to the direction of transport is summarized so that when leaving the Delivery roller pair 5, 5 'no spinning triangle arises when the The fiber structure is twisted into thread F.

Between the output roller pair 3, 3 'and the delivery roller pair 5, 5 'the fiber structure (FB) essentially passes through flat route. The means of transport is perforated Straps 6 formed that the fiber structure (FB) on one side supported. Between the output roller pair 3, 3 'and A pair of delivery rollers 5, 5 'is provided with a suction device, from which a suction air stream emanates, which through which perforated straps 6 formed transport means through the fiber structure (FB) acts by the fiber structure (FB) air from the space below the fiber structure (FB) is sucked in. The width of the suction air flow is through the perforation of the strappy determines. It corresponds to the Width to which the fiber structure (FB) is summarized should.

The perforated strap 6 is guided around the delivery roller 5 and extends against the direction of transport to Nip of the output roller pair 3, 3 '.

The leadership of the strappy 6 causes a known Strappy cage 62, which is designed as a suction device. The one enclosed by the apron 6 and the delivery roller 5 The room is closed off to the side by the suction effect To make perforation 61 of the strappy 6 more effective. The strappy cage 62 is expediently designed as a housing. via a line 67 to a central vacuum device connected.

5, there is a central suction channel 69 provided that placed in the machine below the lower cylinder 3 'and 5' is arranged. This central suction channel 69 extends over all drafting systems, whereby for each Drafting device a nozzle 68 is provided, in which the suction line 67 flows. The connector 68 and the suction line 67 are connected by a plug-in coupling, so that when lifting the top rollers 3, 5, the suction line 67 from the Stub 68 is separable. When lowering the drafting arm with the top rollers then find a clutch with the Nozzle 68 instead.

As can be seen from Fig. 4, this enclosed space is as Groove 66 formed, which is closed towards the delivery roller 5, so that no suction can occur there. The groove 66 is at the front end of the cage, however, open, so that in the Nip of the output roller pair 3, 3 'projecting deflection of the Strappy 6 is also sucked. The width of the groove 66 is expediently to the largest possible width of the strappy perforation 61 matched, so that always a flawless Suction and guidance of the straps 6 is carried out. For better The underside can support and thus seal the groove 66 of the strappy cage 62 also slightly curved in the longitudinal direction be.

By a support 7, which is adjustable, the position of straps 6 to the nip of the output roller pair 3, 3 '. By changing the slope of the strappy 6 together with the strappy cage 62, the distance between the output roller pair 3, 3 'and thus the beginning of the compression set. This inclination adjustment of the strappy 6 with the strappy cage 62 can also be used, as is customary in drafting systems made by clips, each for a certain inclination be used. As can be seen from Fig. 1, by lowering the strappy cage 62 the distance to the lower output roller 3 'less. However, the distance must be so large that the emerging fiber dressing FB between straps 6 and Output roller 3 'can pass freely.

This device works as follows:
The fiber structure emerging from the pair of output rollers 3, 3 'immediately comes into the region of the apron 6. The fiber structure FB is sucked onto the apron 6 by the suction air entering the perforation 61. The suction air flow is bundled through the perforation 61 and exerts corresponding forces on the fibers of the fiber structure FB. The width of the suction air flow is determined by the width of the perforation 61. This is chosen so that the suction air flow has the width of the desired summary when it enters the perforation 61 of the straps 6. It has been shown that the suction air flow not only acts perpendicular to the perforation 61, but also has a transverse effect. This results in a summary of the fiber structure (FB) across the transport direction. The summary begins after the exit from the pair of output rollers and can continue unhindered until it enters the nip line of the pair of delivery rollers 5, 5 ', at least over the length of the suction air flow. This gives the fibers sufficient time to concentrate on the width given by the perforation 61 during transport in this fiber bundling zone.

Through the groove 66 open to the nip of the output roller pair 3, 3 ' this area is also sucked by the suction device 62. This has the advantage that the Output roller pair 3, 3 'emerging fibers immediately sucked and be passed on the straps 6. It also prevents this suction a winding formation on the output roller 3. Depending on how much the fiber material is crimped, can be the ratio of the peripheral speeds between the pair of output rollers 3, 3 'and the delivery roller pair 5, 5' adapted be so that there is a slight lead or lag. Thereby can be avoided that, on the one hand, with heavily curled Fibers too much tension occurs, which is summarizing adversely affected, on the other hand, that for the tension necessary for the transport speed is present is to ensure proper transport of the fiber assembly FB guarantee.

The length of the fiber bundling zone is determined by the distance of the Output roller pair 3, 3 'and the delivery roller pair 5, 5' certainly. It is approximately equal to the distance between the roller pairs 2, 2 'and 3, 3' in the main default field. As a rule, one is sufficient here Clamp line spacing of about 1 1/2 times the fiber length. The The length of the suction air flow is shorter. To reduce the Air consumption is sufficient if the suction air flow at most is effective on half the route. A longer length brings none regarding the summary in the fiber bundling zone better success. The output roller pair 3, 3 'and the delivery roller pair 5, 5 'run at approximately the same peripheral speed, or with a slight, of the fiber material and tension delay depending on the transport speed, as described above.

The strap 6 could of course also the lower delivery roller 5 'loop so that the fiber structure FB on the Strappy 6 rests. The arrangement above the transport level with the wrapping of the upper delivery roller 5 the advantage that the straps 6 can be easily replaced can, because the top rollers 5 on the loading arm of the drafting system are on the fly. The space under the straps 6, or on the opposite side of the transport level is free, so that the fibers, which are only guided on one side, move freely and unhindered by the air flow across the direction of transport can be summarized.

Due to the suction air flow it happens that fiber ends through the Perforation 61 are sucked in, which is then between the straps 6 and the upper roller 5 are clamped. this leads to an unpleasant disorder because these fibers are out of direction follow the fiber bundle FB twisted into thread F. can and are pulled out of this. By appropriate Adjusting the tension of the strappy 6 becomes this loose on the outlet side and stands out from the surface the delivery roller 5 from (indicated in Fig. 1). This will the fiber ends sucked into the perforation 61 released and can the direction of the twisted to thread F. Follow fiber structure.

To be able to carry out the desired adjustment, the Strappy cage 62 designed as a suction device on a support 63 fixed with slots 65. The carrier 63 is on the axis the delivery roller 5 stored and conveniently includes also the suction line 67 with which the strappy cage 62 a vacuum device is connected.

This lifting effect of the strappy is made by suitable selection of the material from which the strappy is made. The strap 6 is therefore expedient from one Made of material that has greater elasticity than is usually the case with straps that are used in drafting systems be used, the case is. Such greater elasticity can be achieved, for example, that the straps used in the fiber bundling zone none Have fabric insert.

This release of the fibers can also be done in other ways can be achieved, for example, in that in the area of Perforation of the strappy the delivery roller 5 a free space has in the form of an annular groove 51 (Fig. 5). This too Way is prevented that sucked fibers between the Straps 6 and the top roller 5 are pinched and closed Disrupt thread formation. In this version usual straps with fabric inlay can be used. Even at high delivery speeds, this leads to a significant improvement in yarn values.

The lifting effect described above can be independent of the Material choice for the strappy 6, for example, as a result can be achieved that the straps 6 after the clamping line of Delivery roller pair 6, 6 ', is braked in the returning run. This can be done easily by placing a leaf spring or the like (not shown).

How far across the transport direction of the FB fiber bundle in the Fiber bundling zone is largely dependent on the size of the perforation 61. The strap 6 therefore has Openings 61 arranged centrally to the running direction, through which the suction air flow passes. will be a coarser one Spun yarn number is the fiber structure to be summarized wider. The size of the perforation 61 is therefore transverse to the direction of transport chosen slightly larger than for fine Yarn where it matters to avoid the spinning triangle summarize the fiber structure more closely. In the direction of transport is the distance between the perforation holes 61 and their size to choose to avoid sucking in fiber ends as far as possible becomes. The distance has proven to be useful for this the perforation holes 61 approximately twice in the transport direction to be as large as the diameter of the perforation holes 61 is. In addition, the compression can also be done by the Negative pressure can be influenced. Depending on the setting of the negative pressure a desired compression can be achieved, so that about the choice of vacuum in extreme cases with or without Spinning triangle can be worked. That way you can the yarn properties are affected, such as. B. Hairiness u. Ä.

The method according to the invention is also particularly suitable for the production of core yarns. For this, an endless thread E, for example a filament, directly into the pair of exit rollers 3, 3 'of the drafting system initiated. This thread E passes through the fiber bundling zone together with the fiber bundle (FB) between the output roller pair 3, 3 'and the delivery roller pair 5, 5 ', in which the fibers by the summary already applied to the continuous thread and then at Leaving the delivery roller pair 5, 5 'to a core yarn (EF) are twisted together (Fig. 5).

With the straps 6 it can happen that on the inside Remove fiber dust and other contaminants. Around Here to effect an automatic cleaning of the straps 6 a cleaning opening 70 on the underside of the strappy cage 62 provided. This cleaning opening 70 extends transversely to the suction groove 66 across the width of the straps 6. At their The cleaning opening 70 is closed at both ends, so that the suction effect only towards the inside of the straps 6 occurs.

By the inventive summary of the fiber structure (FB) after the delay and avoiding a spinning triangle becomes a much higher substance utilization in the thread formation reached. To achieve the same strength as with spinning with a spinning triangle can significantly reduce the rotation become. This means an increase in productivity per spindle by about 20% to 30%.

Claims (26)

1. A process for bundling a fibre composite (FC) which has been finish-drafted in a double apron drafting device and, subsequent to the drafting process, is gathered together in a fibre bundling zone and twisted together to form a yarn, wherein the fibre composite (FC) leaving the pair of output rollers (3, 3') of the drafting device is subjected in the fibre bundling zone to a suction air stream directed transversely to the conveying direction, characterized in that the fibre composite (FC), while being gathered together, passes through an essentially planar distance in which the fibre composite (FC) is supported on one side through the planar conveying means (6), wherein the suction air stream acts on the fibre composite (FC) alone approximately at the desired width of the gathering together while being drawn through the conveying means.
2. The process as in claim 1, characterized in that the circumferential speed ratio between the pair of output rollers (3, 3') and the pair of delivery rollers (5, 5') can be adjusted as a function of crimp of the fibre composite material.
3. The process as in claim 2, characterized in that the speed of the conveying means (6) is dependent upon the speed of the pair of delivery rollers (5, 5').
4. The process as in one or more of claims 1 to 3, characterized in that the gathering together of the fibre composite (FC) is varied by varying the intensity of said suction air stream.
5. The process as in one or more of claims 1 to 4, characterized in that a continuous yarn filament (Y) is introduced directly into the pair of output rollers (3, 3') for the production of a core yarn, said yarn filament passing, along with the fibre composite (FC), through the distance between the pair of output rollers (3, 3') and the pair of delivery rollers (5, 5') and being spun subsequently to form a yarn (YF).
6. A double apron drafting device for spinning machinery for the implementation of the process as in one or more of claims 1 to 5, having a fibre bundling zone which extends after the pair of output rollers (3, 3') of the main drafting zone and is followed by a pair of delivery rollers (5, 5'), wherein a pneumatic condensation apparatus is arranged between the pair of output rollers and the pair of delivery rollers, characterized in that said pneumatic condensation apparatus includes a perforated belt (6) defining the conveying means of the fibre composite (FC) between the pair of output rollers (3, 3') und the pair of delivery rollers (5, 5'), and that said condensation apparatus further includes a suction device (62, 67) which extends along one side of said perforated belt (6) defining the conveying means opposite said fibre composite between said pair of output rollers (3, 3') and said pair of delivery rollers (5, 5'), and which draws in air through said fibre composite (FC).
7. The double apron drafting device as in claim 6, characterized in that the suction device (62, 67) is disposed above the conveying means (8) of the fibre composite (FC) in the area of the upper rollers (5, 3) and draws in air from the space below the fibre composite (FB).
8. The double apron drafting device as in one of claim 6 or 7, characterized in that the perforated belt (6) is looped around the delivery roller (5) and extends parallel to the fibre composite (FC) up to a point closely in front of the pair of output rollers (3, 3').
9. The double apron drafting device as in claim 8, characterized in that the belt (6) includes perforations (61) which are disposed centrally to the direction of running and through which said suction air stream passes.
10. The double apron drafting device as in one of claim 8 or 9, characterized in that the perforations (61) comprise a size which is dependent upon the yarn count which is spun so that larger sized perforations are provided with coarser yarn numbers than are provided with finer yarn numbers.
11. The double apron drafting device as in one or more of claims 8 to 9, characterized in that the belt (6)is comprised of a material the elasticity of which is larger than that of the material for use in aprons of the drafting zone.
12. The double apron drafting device as in claim 11, characterized in that the belt (6) does not contain any fabric insert.
13. The double apron drafting device as in one or more of claims 8 to 12, characterized in that the level of the belt (6) is adjustable with respect to the pair of output rollers (3, 3').
14. The double apron drafting device as in claim 11, characterized by a support the height level of which is adjustable.
15. The double apron drafting device as in one or more of claims 8 to 14, characterized in that the space enclosed by the belt (8) between the pair of output rollers (3, 3') and the pair of delivery rollers (5, 5) is closed off laterally and is connected to a negative pressure source.
16. The double apron drafting device as in one or more of claims 6 to 15, characterized in that the suction device (62, 67) comprises a casing-like belt cage (62) which fills the space enclosed by the belt (6) between the pair of output rollers (3, 3') and the pair of delivery rollers (5, 5).
17. The double apron drafting device as in claim 16, characterized in that the belt cage (62) comprises a groove (66) in the area of the belt perforations (61), in which groove a suction pipe (67) ends.
18. The double apron drafting device as in one or more of claims 6 to 17, characterized in that the suction device (62, 67) is closed off in relation to the delivery roller (5).
19. The double apron drafting device as in one or more of claims 6 to 18, characterized in that the suction device (62, 67) is open to the nip of the pair of output rollers (5, 5').
20. The double apron drafting device as in one or more of claims 6 to 19, characterized in that a means is associated with the suction device (62, 67) for the variation of the suction air stream effective in said suction device.
21. The double apron drafting device as in one or more of claims 6 to 20, characterized in that the belt cage (62) further comprises a cleaning opening (70) which is directed to the inside of the belt (6) and is connected to a suction line (67).
22. The double apron drafting device as in claim 21, characterized in that the cleaning opening (70) extends at a right angle to the suction groove (66) over the width of the belt (6).
23. The double apron drafting device as in one or more of claim 15 to 22, characterized in that a suction channel (69) fixedly installed in the machine frame extends in the area of the lower rollers (3', 5'), to which channel the suction means (62, 67) which are movable along with the upper rollers (3, 5) are connected each with a coupling.
24. The double apron drafting device as in one or more of claims 8 to 23, characterized in that said perforated belt comprises an adjustable tension so that the belt (6) can be loosened from the delivery roller (5) in the exit area.
25. The double apron drafting device as in claim 24, characterized in that the belt cage (62) is attached to a support (63) and is adjustable in relation to the delivery roller (5).
26. The double apron drafting device as in one or more of claims 8 to 25, characterized in that the delivery roller (5) around which the belt (6) is looped comprises a free space (51) defined therearound in the area of the perforated belt (61).

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