GB2228950A

GB2228950A - Centrifugal spinning

Info

Publication number: GB2228950A
Application number: GB9004477A
Authority: GB
Inventors: Manfred Pueschmann; Volker Roland; Peter Voidel
Original assignee: Kombinat Textima VEB
Current assignee: Kombinat Textima VEB
Priority date: 1989-03-01
Filing date: 1990-02-28
Publication date: 1990-09-12
Also published as: DE4002230A1; DD285518A7; IT1244043B; IT9047640A1; IT9047640A0; GB9004477D0

Description

1 A METHOD OF BUILDING UP AND WORKING OFF A LAP CONSISTING OF PARTIALLY

TWISTING THREAD, WITHIN A CENTRIFUGAL SPINDLE The invention relates to a method of building up and working off a lap consisting of partially twisted fibre or thread within a centrifugal spindle in which the principle (conventional with ring spinning) of creating a constant and consistently offset basic travel until a specific total travel is reached is incorporated while any lacking twist is imparted to the thread during the working-off stage.

It is known to impart to a fibre thread some of its twist by means of a centrifugal spindle, the thread being then deposited temporarily in the form of a lap and, when the desired degree of filling is achieved, to draw it from the centrifugal spindle, wind it onto a spool or bobbin and in so doing impart the rest of the twist to it. This method is described in DD 22 772 and DE-OS 2 229 263. What is not described is how the partially twisted thread is deposited in the centrifugal spindle and is removed again therefrom. The very manner of building up and working off the thread lap is of great importance when the thread is being drawn off in order to avoid thread breakages and to avoid the simultaneous 2 detachment of several turns of thread which could result in looping. In this connection, the magnitude and fluctuation in thread tension plays a vital role. To this extent, the method of building up the thread lap which is conventional with normal centrifugal spinning, where the thread is constantly laid in cross-wound layers over the total travel, is not suitable for working off a partially twisted thread while at the same time providing the residual twist.

An object of the invention is to provide an improved method of building up a lap within a centrifugal spindle from partially twisted thread and to work it off again so that the remaining twist can be imparted without breaking and without loops.

It has been discovered that with regard to a thread which is to be produced without loops, it is advisable for the construction of the thread lap to be produced with a constant and steadily offset basic stroke until a specific total stroke is reached, such as the principle which is applied in ring spinning for cop build-up.. A number of specific conditions are required for working off the thread lap as described hereinafter.

The essence of the invention resides in so building up and again working off the lap which is to be formed from partially twisted thread in a centrifugal spindle that the thread tension available to pull off the thread 1 3 is maintained within specific limits and can be influenced and in that the thread windings are pulled off individually. In accordance with the invention this can be achieved in that, using the principle of creating a constant basic travel which is steadily offset until a specific total travel is reached, such as is used for cop build-up in ring spinning, the thread lap is built up from the vicinity of the spindle bottom in the direction of the entry aperture, the pattern of speeds of the basic travel movement in both directions being equal and the speed itself being so low that the thread windings are laid virtually parallel alongside one another, and that to work off the thread lap the thread deflection point arising due to the position of the thread guide tube moves in the opposite direction without thereby performing the basic travel movement.

Preferably, when the total travel is attained, in order to work off the thread lap the offset and basic travel movement are so terminated that the thread deflection point is opposite the deflection point of the basic travel movement which is closer to the bottom of the centrifugal spindle. Immediately afterwards, the thread deflection point is shifted at high speed in the direction of the spindle bottom by an amount of up to 5 mm and then onwards in the same direction so that at the end of work-off it is in a range from 5 mm in front of to 5 mm after the starting point of lap build-up.

4 The invention is explained in greater detail hereinafter with reference to the following description and the accompanying drawings, in which:

Figure 1 is a part-sectional representation of a spindle and a guide tube showing the thread lap being constructed; Figure 2 depicts the disposition of the thread deflection point at the end of the lap build-up; Figure 3 depicts the location of the thread deflection point immediately after commencement of thread lap work-off; Figure 4 depicts one position of the thread deflection point during lap work-off; Figure 5 depicts another position of the thread deflection point during lap work-off; Figure 6 depicts one position of the thread deflection point shortly before the end of the lap workoff; and Figure 7 depicts another possible position of the thread deflection point shortly before the end of the lap work-off.

Figure 1 shows a centrifugal spindle 1 and a thread guide tube 2 at a specific time during build-up of the thread lap 3. Lap build-up takes place starting from the vicinity of the spindle bottom 5 and moving in the direction of its entry aperture 6. The position of the thread guide tube 2 is, as shown in the drawings, such that the thread deflection point A is just at the end of the basic travel h, and of the travel offset h2 which has been reached thus far. At completion of the constant basic travel h, and the constant travel offset, a conical part 4 is created at the beginning and end of the thread lap 3. The basic travel itself is, in contrast to the ring spinning mentioned by way of example, completed in both directions with the same speed pattern and moreover at relatively low speed so that the individual thread windings are laid approximately parallel alongside one another.

If, as shown in Figure 2, the predetermined total travel h is reached, the pull-off of thread 7 through the thread guide tube 2 commences. For this purpose, the total travel and offset movement are so immobilised that the thread deflection point A is opposite the deflection point of the basic travel movement which is close to the bottom 5. Immediately afterwards, there is a rapid shift of the thread deflection point A by an amount 'a' which may amount to up to 5 mm (Figure 3). Thus, the tension in the thread 7 which is to be drawn off is increased, which has a favourable effect on individual detachment of the thread windings.

Further work-off of the thread lap 3 is shown in Figures 4 and 5. It is evident that during work-off the 6 thread deflection point A is displaced in the direction of the bottom 5. In contrast to lap build-up, there is no basic travel movement. The point A can now be so shifted that it leads the point B at which the conical part 4 of the thread lap 3 merges into the cylindrical part of the lap (Figure 4) or trails behind it (Figure 5). Thus, the tension in the thread 7 which is to be pulled off can be varied within certain limits which takes place having regard to the centrifugal force acting on the thread and as a function of the thread material and the fineness of the thread and which has an effect on an ordered detachment of the individual thread windings.

At the end of working off the thread lap 3, the thread deflection point A is either inside the range 'b' (Figure 6) or is within the range 'c' after the point at which lap formation has started.

7

Claims

1. A method of building up and working off a lap consisting of partially twisted thread laid within a centrifugal spindle with a guide tube by creating a constant and consistently offset basic travel until a specific total travel is reached while any still lacking twist is imparted to the thread during the working-off stage, said method comprising building up the thread lap from the vicinity of a bottom of the spindle in the direction of an entry aperture thereof with the pattern of speeds of the basic travel movement being the same in both directions and controlled so that the layers of thread are deposited virtually parallel with one another and that for working off the thread lap the thread deflection point resulting from the position of the guide tube moves in the opposite direction without carrying out the basic travel movement.

2. A method according to claim 1, wherein the offset and basic travel movement are so completed for working off that the thread deflection point is opposite the reversal point of the basic travel movement which is closer to the bottom.

3. A method according to claims 1 or 2, wherein immediately upon completion of the offset and basic 8 travel movement the thread deflection point is displaced at high speed by an amount of up to 5 mm in the direction of the bottom.

4. A method according to any one of claims 1 to 3, wherein during working off of the thread lap the thread deflection point is further displaced in the direction of the bottom so that at the end of working off it is in range from 5 mm before to 5 mm after the starting point of lap build-up.

5. A method substantially as described with reference to and as illustrated in any one or more of the Figures of the accompanying drawings.

Published 1990w, The Patent Office. StzLte House. 66771 High Holborn. LondonWClR4-AP Fumner copies xnky be obtainedfrom The Patent Offi, e Sales Branch. St Ma_-y Cray. Orpint.0n. Kent BR5 3RL Printed by Multiplex tech:niques ltd. St Mary Cray. Kent. Con 181