US3451209A - Over-end winding of yarn - Google Patents

Description

ovEafENQ-WINDING oF YARN Filed Aug. 21, 196'? PACKAGE DIAMETER (INU/E5) A lllnleys United States Patent O 3,451,209 OVER-END WINDING F YARN Douglas Chisholm Bisset, Alan Keith Dunnell, Clive Williams Hooper, and Kenneth Andrew Key, Pontypool, England, assignors to Imperial Chemical Industries Limited, London, England, a corporation of Great Britain Filed Aug. 21, 1967, Ser. No. 661,859 Claims priority, application Great Britain, Sept. 1, 1966, 39,113/ 66 Int. Cl. D02g; D01h 13/00; B65h 53/12 U.S. Cl. 57-156 4 Claims ABSTRACT 0F THE DISCLOSURE Regions of patterning in a yarn package, due to e.g. ring-tilt, are avoided by shifting between at least 3 spindle speed values during the winding cycle.

The invention concerns improvements in or relating to the over-end winding of yarn.

Over-end winding of yarn, as on the well-known ring spinning machine, is practised when it is desired to impart a twist to the yarn by the act of winding.

A common instance of such over-end Winding is to be found in the drawtwisting of synthetic polymer iilaments; and the present invention will be described in relation to such drawtwisting, although it is to be understood that the invention is not limited thereto.

A `drawtwister is essentially a downtwister in which are incorporated roll mechanisms for drawing undrawn yarn. Usually, such mechanisms consists of nip rolls rotated at a given speed acting as feed rolls; and a draw roll and separator roll combination, the former roll of which is rotated at the required higher speed to effect the drawing action on the tilaments in question. From the draw roll, the drawn filaments proceed in a generally downward direction to a thread guide positioned axially, or near-axially, of the spindle of a ring and traveller ring spinning mechanism. This thread guide is sometimes known as the balloon guide, as the yarn is ballooned beneath it by virtue of the rotation of the traveller around the ring. The filaments are then wound up on a bobbin mounted on the rotating spindle, by passage around the traveller which is itself rotated around the ring and by reciprocation of the ring, in its rail, tray or other carrier, in the axial direction of the spindle according to the builder motion required for the particular yarn package to be wound on the bobbin.

It is a quite usual artilice to tilt the ring of the ring spinning mechanism in order that the filaments shall be laid on to the bobbin and yarn package in helical coils having a wavy path rather than a flat helical one. An angle of tilt of between 3 and 6 is usual; although an angle even as low as 1 may be selected and will donate an appreciable wave component to the laying-on path of the yarn. Rings are not generally set to a greater degree of accuracy than within i-l/f.

Such ring tilt is at least a major factor predisposing the formation of regions of patterning at certain radii of the package build, owing to the coincidence of adjacent coil loci. The incidence of these various regions of patterning, which patterning is to be avoided both from the technical point of view of package stability and yarn take-off characteristics and from the point of View of appearance, can be calculated, e.g. by analogue computer, for any given process involving a drawtwisting wind-up; and hence it is possible to so programme the Winding conditions that the regions of patterning which normally would occur shall be avoided.

One method of programming the winding conditions which has been proposed is to alternate the spindle speed between two values, switching from one to the other and back again, and so on, when the stages of winding are calculated to be reached at which patterning will occur at the respective spindle speed to be departed from.

The conditions leading to patterning are related to the wind ratio: that is, the ratio of the number of revolutions per minute of the point of winding-on the package to the number of revolutions per minute of the traveller. Patterning will be severe at and around integral values of iwind ratio; and consequently the spindle speed programme is devised, according to the above known method, so that the speed is shifted to the alternate one when the winding conditions approach a value of wind ratio, for the primary speed, at which patterning will occur, and is then shifted back to the primary one when similarly patterning is due to be encountered at the alternate speed.

Although the above method appears theoretically t0 provide an answer to the patterning problem in over-end winding, we have found that in practice it is close to impossible to select the respective alternate spindle speeds to produce a winding programme that effectively avoids the patterning conditions throughout the winding of a full-Weight, e.g. 4 lb., yarn package. This is because the occurrence of patterning is not restricted to the moments during winding when the pattern-inducing wind ratios are established, but is prolonged for a period either side of those times; and therefore, unless the regions of patterning are less than the spacing between pattern-inducing wind ratios, which will certainly not be the case at the worst ratios, if t-hese are to be encountered in the package, it will not be possible merely by alternation of speeds to avoid such regions altogether.

Again, especially when the adjacent pattern-inducing wind ratios are not multiples of one another, it is most likely that the attempt to avoid one such wind ratio by shifting to the alternate speed will merely result in a collision with another such wind ratio.

The invention, therefore, is based on the proposition that the spindle speed in an over-end winding process is programmed to be shifted between at least three selected speeds in a manner so as to avoid the calculated regions of patterning in the yarn package being wound.

This invention comprises a method of winding yarn by over-end winding on to a package formed with the aid 0f a rotating spindle, wherein the speed of rotation of the spindle is programmed so as to be shifted between at least three selected values of speed in a manner such as to avoid calculated regions of patterning that would otherwise occur in the package being wound.

Shifting between the speeds may be in a cyclical, or in a repeated sequential, progression; or, alternatively, it may be in a pre-determined but unordered manner calculated, e.g. graphically, to provide the best pattern-avoidance programme. v

For instance, if three spindle speeds A, B and C are to be used, the shift may be cyclically from A to B to C to B to A and so on, or repeated sequentially from A to B to C to A to B to C and so on. Alternatively, any programme of unordered shifts can be predetermined, as, for example, A to C to B to C to A to B.

The selected speed are obviously chosen so as to be as close to the optimum speed for the process as possible, compatible with providing the required disparity in speed to enable the calculated patterning regions to be avoided.

Shifting from one speed to another is achieved in an abrupt manner to cross straight through, or move quickly away from the patterning region, i.e. the invention is not concerned with any gradual variations in spindle speed taking place over the entire winding period or a substantial part thereof.

On the other hand, a high frequency low amplitude variation in speed about any or all of the selected speeds may be imposed, in order to scramble the wind ratio and thus to disperse any patterning which may not have been completely avoided by the abrupt shifts in spindle speed. The scrambling conditions should not, of course, be such as to cause the wind ratio to re-enter the main patterning regions.

Although the use of three spindle speeds has been instanced above, it is to be understood that any number greater than two may be employed according to the invention, although it is contemplated that any given programme will always be worked out for the minimum number of speeds compatible with effective pattern avoidance.

The spindle speed shift programme is first calculated for the particular process, and then that programme is applied to a controller for a variable speed device driving the spindle shaft of the machine. The programme can be applied in sundry ways, the motivation for which derives either from the mechanical operation of parts of the machine, for instance the builder mechanism, or from external programming means, as for instance timing mechanism, punched cards, tapes, etc.; not operatively connected with the machine.

Whilst the invention is applicable to the winding of yarn packages on all kinds of bobbin or tube, it will be understaood that the particular programme to be selected will be affected by the shape of the tube, e.g. as to whether it is frusto-conical or cylindrical.

As an example of the invention, the following conditions were applied to a process in which 70 denier 30 lament yarn of polyhexamethylene adiparnide nylon 66 was produced by drawing at a draw ratio of 3.36 at a speed of 2,500 feet/minute, and was wound-up by a ring and traveller system of a Rieter drawtwister in a 3 lb. double taper yarn package on a 1.85" diameter tube with a long-to-short traverse build:

Draw roll peripheral speed Constant at 2,500 feet/minute, (or

such speed at to produce a winding on speed of that value). Ring tilt 3 Spindle speeds:

A 8,500 r.p.m. B 9,120 r.p.m. C 9,850 r.p.m.

Spindle speed shift programme (A-C-B-A-C-B-A-C-B-A-B-A-B-C) By the above programme, it was possible to wind the package so that substantially n0 patterning Was present at any radius thereof, particularly avoiding the patterning regions corresponding to the wind ratios 1:2, 2:5, 1:3, 2:7 and 1:4, as shown in the accompanying drawing which is a graph of the spindle speed/yarn speed ratio against package diameter. The patterning regions are shown as shaded bars across the graph; and the spindle speed/yarn speed ratio line is plotted across these regions, avoiding them all, as the package diameter rises from 1.85 inches to 5 inches through the full period of winding.

We claim:

1. In a method of winding yarn on a machine in which method the yarn is wound over-end of a package mounted for rotation on a spindle and the speed of rotation of the spindle is changed during the Winding of the package in a manner so as to avoid regions of patterning in the package that would otherwise occur owing to the existence of certain wind ratios, the improvement comprising changing the spindle speed abruptly between at least three selected values according to a programme, successive changes being made as the wind ratio approaches values giving rise to any substantial degree of patterning whereby regions of patterning in the package are avoided.

2. A method as in claim 1 including monitoring a variable in the winding operation to obtain a signal and wherein the spindle speed is changed in accordance with a signal derived from said signal.

3. A method as in claim 2 wherein the signal is derived from monitoring the building motion of the winding operation.

4. A method as in claim 1 wherein a high frequency low amplitude variation in speed is imposed on the spindle about at least one of the selected speeds in order to scramble the wind ratio and thus to disperse any patterning which may not have been completely avoided by the abrupt shifts in spindle speed.

References Cited UNITED STATES PATENTS 2,658,689 ll/1953 Waldrop 242-181 3,137,987 6/1964 Potts 57-55.5 3,235,191 2/1966 Engel-man et al. 242-18.1 3,241,779 3/1966 Bray et al. 242-181 3,325,985 6/1967 Bucher 242-263 XR JORDAN FRANKLIN, Primary Examiner.

W. H. SCHROEDER, Assistant Examiner.

U.S. Cl. X.R. 57-93; 242-18.1

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