GB2260143A

GB2260143A - Apparatus for texturing synthetic,multifilament threads

Info

Publication number: GB2260143A
Application number: GB9218211A
Authority: GB
Inventors: Gunter Konig
Original assignee: Zinser Textilmaschinen GmbH
Current assignee: Oerlikon Textile GmbH and Co KG
Priority date: 1991-09-10
Filing date: 1992-08-27
Publication date: 1993-04-07
Anticipated expiration: 2012-08-27
Also published as: DE4130059C2; GB2260143B; JPH06116822A; DE4130059A1; GB9218211D0; CH685710A5

Description

-2,cl t-7 "Apparatus for handling synthetic, multifilament continuous

threadsly This invention relates to apparatus for handling synthetic multifilament continuous threads with a thread delivery unit, an intermingling unit, a thread brake and a winding unit for the thread, arranged successively in the direction of travel of the thread.

In a known apparatus of this kind (DOS 17 10 639) the thread brake is in the form of a yarn tensioning device. It thus tensions the thread - in other words: it increases the tensile stress in the thread entering the winding zone to the level required for proper winding. The thread tension in the intermingling zone may advantageously be set to a lower level.

In fact, it is known (Chemiefasern/Textilindustrie, October 1980, page 822) that a reduction in the thread tensile force in the intermingling zone is apt to increase the intermingling density and/or the possible processing speed.

A simple thread brake of the kind described increases the tensile force in the departing thread and reduces it in the incoming thread. It does, however, have the disadvantage that it reduces changes in the thread tension in terms of the differences in thread tension between the incoming and outgoing thread but instead passes them on unaltered. This has the serious disadvantage, in the present type of use, that the thread tension in the intermingling zone is also affected by changes to which it is prone as a result of the varying influences in the winding zone. The effect of intermingling depends, however, to a critical extent on the level of thread tension which prevails in this intermingling zone. Fluctuations in the thread tension in the intermingling zone therefore result in varying degree of twist along the thread, which may affect the quality of the thread produced to the point of making it unusable.

Therefore, other constructions have been proposed for preventing the thread tension required to achieve sufficiently firm winding onto the bobbins in the winding zone from affecting the intermingling zone which precedes it. Thus, it is known to interpose an additional active thread feed mechanism, e.g. a composite/shifting roller or pair of rollers (DEOS 32 48 396) or a stepped composite roller (DE-OS 17 85 442, GB-PS 1 181 004). However, these proposed solutions are of complicated construction and are therefore expensive.

According to the present invention there is provided apparatus for handling synthetic multifilament continuous threads having a thread delivery mechanism, an intermingling unit, a thread brake and a winding unit for the thread, comprising a sensor which scans the tension in the thread in the intermingling zone or in the winding zone and adjusts the braking force of the thread brake in order to maintain a substantially constant tension in the thread in the intermingling zone.

By means of this arrangement there is provided a construction wherein the thread tension in the winding zone is easily and reliably prevented from having an impact on the preceding intermingling zone. If the thread tension in the winding zone or in the intermingling zone is altered, the thread brake is automatically adjusted so that the thread tension in the intermingling zone remains at least substantially constant.

If, for example, the thread tension inthe winding zone increases, this increase issensed and the braking action of the thread brake is increased, so as to minimise the effect which the thread tension in the winding zone has on the intermingling zone-and so that the thread tension in theintermingling zone remains k Z substantially constant. As a result the thread tension in the winding zone is indeed further increased but has no harmful effect on the fixed thread which has already been intermingled.

As a result there is also the advantage that in spite of the existence of a high thread tension, either needed or desired, in the winding zone, any impact on the desirably lower thread tension in the intermingling zone is avoided by simple technical means. Depending on the given braking action of the thread brake and the thread tensile force. which is to some extent capable of being influenced, in the travel of the thread between the feed mechanism and the winding device, the thread tensile forces in the intermingling zone and in the winding zone can be adjusted.

Purely mechanical as well as mechanical/pneumatic thread brakes are known (DOS 21 19 880, DOS 15 35 145, DBGM 70 03 152, CH 538 417) which themselves sense the thread tension in the incoming or outgoing thread and vary their braking action so as to even out the thread tension. Thread brakes of this kind can be used for the present application.

A particularly sensitive and rapidly reacting apparatus comprises, according to one embodiment, a measuring unit which scans the thread tension in the intermingling zone or in the winding zone and is connected via control means to positioning means which adjust the thread brake. An electromagnetically controlled thread brake which may be used for this purpose is known from DGM 87 13 749.

Some embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:- Fig. 1 is a diagrammatic view of apparatus for handling synthetic, multifilament continuous threads with cold drawing and a winding unit consisting of ring, traveller and spindle; Fig. 2 shows the basic operation of a simple selfregulating thread brake; Fig. 3 shows apparatus for handling synthetic, multifilament continuous threads with warm drawing and a winding unit for producing a cross-wound bobbin; Fig. 4 shows a schematic diagram of the course of the thread tension along the travel of the thread.

According to Fig. 1 the apparatus 1 for handling a synthetic multifilament continuous thread 2 has a feed bobbin 3 after which is provided a thread guide 4. The thread 2 runs through a pair of feed rollers 5 and is guided to a drawing peg 6 which serves to fix the point where drawing begins.

Passing through a drawing zone 7 the thread 2 reaches a composite/shifting roller assembly 8/9, is looped several times round it and then runs into an intermingling zone 10 in which its filaments are intermingled by means of an intermingling unit 11, i.e. irregularly interlaced with one another. The construction and method of operation of such pneumatically operated intermingling units are known and will therefore not be described in detail here.

A self-regulating thread brake 12 is provided downstream of the intermingling unit 11 in the direction of travel of the thread.

via a winding zone 13 the thread 2 passes through a thread guide 14 to a winding unit 15 which consists of a ring 16, a traveller 17, a spindle rail 18, a spindle 19 and a winding bobbin 20.

The thread tension in the region between the composite/shifting roller assembly 8/9 and the winding unit 15 is determined essentially by the choice of traveller 17 and is divided by means of the thread brake 12 into a region of lower thread tension in the intermingling zone 10 and a region of higher thread tension in the winding zone 13.

The arrangement of the thread brake 12 between the intermingling unit 11 and the winding unit 15 ensures that the thread tension in the winding zone 13 on the one hand is sufficiently high for a fixed bobbin construction but on the other hand in the intermingling zone 10, i.e. in the region of the intermingling unit 11. the thread tension is at the low level which is advantageous for the operation thereof.

The thread brake 12 has a sensor 21 which scans the thread tension in the thread 2 departing from the thread brake 12 in the winding zone 13 and moves the thread brake, by means of the operative connection 22 shown by broken lines, so that any changes or fluctuations in the thread tension in the winding zone 13 do not have an impact on the intermingling zone 10, i.e. the thread tension in the intermingling zone remains as constant as possible.

If the sensor 21 does not, as shown in the drawing, abut on the thread 2 leaving the thread brake 12 but instead abuts on the thread entering the thread brake, it measures the thread tension in the intermingling zone, since in this arrangement the thread brake 12 separates the two zones from each other.

Fig. 2 shows the construction of a simple, self regulating, purely mechanical thread brake. The thread 2 runs via two fixed guide pins 23, 24 between which is arranged another guide pin 25. This additional guide pin 25 sits on a lever 26 which is fixedly clamped at one end and is constructed as a spring rod in its region 27 between this fixing point and the articulation of the guide pin 25. Its other end merges with the sensor 21 which abuts on the thread 2. over the spring rod runs a slide member 28 which is movable on a rigidly secured rail 29 in the direction of the arrow A.

The braking action of the thread brake 12 on the thread 2 depends on the depth of penetration of the guide pin 25 between the guide pins 23 and 24, which is determined by the position of the lever 26, which in - 6 turn depends on the tensile force in the thread 2. if the thread tension increases, the sensor is shifted to the left, by virtue of its sprung mounting, and presses the guide pin 25 deeper between the guide pins 23 and 24, thereby increasing the braking action of the thread brake 12.

The position of the slide member 28 along the spring rod 27 fixes the clamping point of the spring rod and thus controls the effects of a change in the thread tension on the braking action.

Fig. 3 shows apparatus 1 for treating synthetic, multifilament continuous threads in which the winding unit 15 serves to produce a crosswound bobbin 30. This crosswound bobbin 30 is connected, via its outer periphery, with a drive roller 31, whilst a thread guide 32 travels back and forth on a guide 33 and winds the thread 2 on the crosswound bobbin 30 which is rotated by the drive roller 31. In this construction, which is intended for warm drawing, the thread 2 passes behind the feed rollers 5 and runs through a heater 34 from which it passes via the drawing zone 7 and the composite/shifting roller assembly 8/9 to the intermingling unit 11, downstream of which is provided a freely rotatable guide roller 35 pulled along by the thread. As a result of the guiding of the thread carried out by the guide roller 35 the overall height of the machine is reduced and fluctuations in the thread 2 in the intermingling zone 10 or in the winding zone 13 are kept remote from the other zone in each case.

In the embodiment, the thread tension in the region between the composite/shifting roller assembly 8/9 and the winding unit 15 is determined by the ratio of the circumferential speeds of the composite roller 8 and the drive roller 31 and, as in the embodiment described above, is divided by means of the thread brake 12 into a region of lower thread tension in the intermingling zone 10 and a region of higher thread tension in the winding :! l, 1 1 1 - 7 zone 13.

The thread sensor 21 is connected here to a transmitter 36 which transmits a measurement, depending on the thread tension, to a control apparatus 37 which acts upon a positioning device 38, also electrical, for the thread brake 12. The average braking action of the thread brake can be set by means of the control apparatus 37.

Fig. 4 shows the course of thread tension along the travel of the thread. The x axis represents the thread tension K, whilst the y axis defines the thread travel F through the apparatus. The figures on the left of the y axis denote the corresponding zones, whilst the figures on the right indicate the units along the travel of the thread.

In the drawing zone 7 the thread tension 39 is at its maximum, for the purpose of the process. In the embodiment of Fig. 1 it is divided by the drawing peg 6 into a region of lower thread tension (at the top) and a region of higher thread tension (at the bottom) shown by broken lines. In the region between the composite/ shifting roller assembly 8/9 and the winding unit 15 a thread tension shown by broken lines would be obtained which is split up by the thread brake 12 into the lower thread tension 40 in the intermingling zone 10 and the higher thread tension 41, 42 in the winding zone 13.

The regulating effect of the thread brake 12 ensures that the thread tension 40 in the intermingling zone 10 is maintained even if the thread tension in the winding zone fluctuates, for example, between the values 41 and 42.

The thread tension 40 in the intermingling zone 10 can be adjusted by means of the control device 37, so that even when there are different thread tensions 41, 42 in the winding zone 13 the desired thread tension 40 can be maintained in the intermingling zone 10.

The illustrations are merely examples of possible embodiments. The components of cold or warm drawing, cops or crosswound spool winding, mechanical or electrically controlled thread brake, scanning of the thread tension in the intermingling or in the winding zone etc. may also be combined in other ways.

Claims

1. Apparatus for handling synthetic multifilament continuous threads having a thread delivery mechanism, an intermingling unit, a thread brake and a winding uni for the thread, comprising a sensor which scans the tension in the thread in the intermingling zone or in the winding zone and adjusts the braking force of the thread brake in order to maintain a substantially constant tension in the thread in the intermingling zone.

2. Apparatus according to claim 1, wherein the sensor is connected to a measuring unit which is connected via a control apparatus to a positioning device which adjusts the braking force of the thread brake.

3. Apparatus according to claim 1 or 2, wherein a guide roller is provided upstream of the thread brake.

4. Apparatus according to claim 1 or 2, wherein a guide roller is provided downstream of the thread brake.

5. Apparatus for handling synthetic multifilament continuous threads substantially as hereinbefore described with reference to the accompanying drawings.