WO1990004668A1

WO1990004668A1 - Improvements in or relating to ring spinning

Info

Publication number: WO1990004668A1
Application number: PCT/GB1989/001246
Authority: WO
Inventors: Isaac Porat; Carl Anthony Lawrence
Original assignee: The University Of Manchester Institute Of Science And Technology
Priority date: 1988-10-21
Filing date: 1989-10-20
Publication date: 1990-05-03
Also published as: AU4508189A; GB8824727D0

Abstract

A ring spinning process comprises fluid jet twisting the yarn upstream of the region in which it orbits the rotary yarn package. Ring spinning apparatus comprises a rotary spindle coaxial with a ring and a yarn guide through which yarn is fed in use to orbit the growing yarn package, a feed mechanism from which yarn is fed on a feed path to said guide, and fluid jet twisting means on said feed path.

Description

IMPROVEMENTS IN OR RELATING TO RING SPINNING

This invention relates to ring spinning. The ring spinning process is well known and comprises a rotary spindle driving a bobbin mounted thereon within a fixed coaxial ring carrying a traveller for freely circulating the circumference of the ring. In operation, yarn being spun extends from a roving in a drafting system, through a pigtail guide above the spindle, through the clearance between the ring and the traveller and onto the rotating bobbin. Because the yarn passes through the traveller the latter will simultaneously circulate the ring's circumference with the action of winding. Each rotation of the spindle will cause one traveller circulation of the ring which will insert one turn of twist into the length of yarn. The frictional drag between the traveller and the ring slows the traveller, sufficiently to enable the threaded yarn length to be wound onto the bobbin at a rate equal to the speed at which the drafted material leaves the front pair of drafting rollers. The winding-up of the threaded yarn length occurs at a much reduced rate compared to the insertion of twist, e.g., if the ratio is 1:80 and the bobbin diameter is 25mm, approximately 80 turns of twist would be inserted before one circumferential length of the threaded yarn is wound onto the body.

A disadvantage of the ring spinning process is that the heat generated by the frictional drag of the ring on the traveller cannot be dissipated sufficiently quickly to allow very high traveller speeds to be used. Furthermore, power consumption is high because the bobbin has to be rotated to insert twist. It is an object of the present invention to obviate or mitigate the aforesaid disadvantages.

According to a first aspect of the present invention there is provided a ring spinning process comprising fluid jet twisting the yarn upstream of the region in which it orbits the rotary yarn package.

According to a second aspect of the present invention there is provided ring spinning apparatus comprising a rotary spindle coaxial with a ring and a yarn guide through which yarn is fed in use to orbit the growing yarn package, a feed mechanism from which yarn is fed on a feed path to said guide, and fluid jet twisting means on said feed path.

The invention will now be further described by way of example only, with reference to the accompanying drawings in which:-

Fig. 1 is a diagrammatic, part sectional side view of one embodiment of ring spinning apparatus in accordanc.e with the invention;

Fig. 2 is a longitudinal section of one embodiment of fluid jet twister for use in apparatus of the invention, and

Fig. 3 is a cross-section on line III-III of Fig. 2.

Referring now to the drawings, the ring spinning apparatus comprises a drafting system 1 comprising three sets 2, 3, 4 of paired rollers for reducing the mass per unit length of a roving 5 to the value for the required yarn. Below the drafting system is a rotary spindle 6 carrying a bobbin 7 on which is shown a partly formed yarn package 8. The spindle 6 is mounted coaxially within a fixed ring 9 (shown in cross section) on a ring rail 10. A traveller 11 in the form of a C-shaped clip is clipped loosely onto the ring 9 so that it can travel freely around the spindle 6 on the ring 9. A pigtail or lappet yarn guide 12 is arranged axially above the spindle 6 and a fluid (in this case air) jet twister 13 is provided on the yarn path between the yarn guide 12 and the front drafting rollers 4.

To initiate twisting, a length of yarn is wound onto an empty bobbin 7 which is then fitted onto the spindle 6. The appropriate end of the yarn is pulled from the bobbin 7, threaded through the clearance between the ring 9 and the traveller 11, passed through the yarn guide 12 and the air jet twister 13 and placed in contact with the drafted material at the nip line of the roller set 4.

The spindle 6 and the drafting rollers 2, 3 and 4 are then driven to rotate. The rotation of the spindle 6 will begin winding the threaded yarn 14 onto the bobbin 7 while the traveller 11 circulates on the ring 9. As explained above, friction between the ring ^* 9 and the traveller 11 causes the traveller 11 rotationally to lag the spindle 6 whereby the yarn

14 is wound into the package 8 while at the same time having twist imparted thereto. The length of yarn 14 between the yarn guide 12 and the circulating traveller 11 orbits the spindle 6 as what is called a "yarn balloon".

The twister 13 may be of any suitable design one of which is illustrated in Figs. 2 and 3. The twister 13 has a generally cylindrical shell 15 between which and a central core 16 is an air plenum

A chamber. The core 16 has a circular section yarn

Λ passageway 17 extending therethrough from a yarn inlet 18 to a flared yarn outlet 19. The body shell

15 has a compressed air inlet pipe 20 for directing compressed air into the plenum chamber and in the direction of the arrows towards four nozzles 21 in the core 16. The nozzles 21 are inclined in the direction of yarn travel (Fig. 2) and are equiangularly spaced around the yarn passageway 17 in substantially tangential relationship therewith (Fig. 3). In use, the air jet twister introduces a false twist in the yarn. This inserted twist is removed because effectively the twister generates opposite twisting torques, i.e. S-twist and Z-twist. If the S-twisting torque acts on the yarn length above the twister, the Z-twisting torque will act on the yarn length below the twister. However, the kind of twister used in the invention also wraps the yarn in the sense that the edge fibres of the drafted material are made to wrap around the body of the yarn during twist insertion. The action of untwisting then only serves to tighten the hold of these wrapping surface fibres. The propagation of true twist from the yarn package 8 back to the drafting system 1* interacts with the false twisting and wrapping process being carried out in the air jet twister 13 so as to enhance the benefit of the wrap-spinning process to the ring spinning process.

The combination of air-jet wrap twisting and ring spinning allows the structure and properties of the spun yarn to be altered by varying the relative contributions of twist insertion by the ring and traveller mechanism and wrapping by the air jet twister. For example, in spinning 100% staple fibres the wrapping action of the air jet twister can be used to alter the surface appearance of the yarn in an advantageous manner, e.g by spinning yarns to various levels of hairiness. The wrapping action also enables significantly lower twist levels to be used with the ring and traveller thus making possible the production of yarns which are bulkier than conventional ring spun yarns. The combination of increased hairiness and lower twist also enables a softer handle to be given to a yarn than could previously have been obtained.

In an advantageous development of the invention the process is applied to the production of a core yarn as used for example in the production of a sewing thread. Such threads have a filament centre wrapped with a staple fibre sheath. The introduction of a filament for production of core yarns may be accomplished immediately behind the roller set 4 of the drafting system 1 as is indicated by dotted line 22 in Fig. 1.

Claims

1. A ring spinning process comprising fluid jet twisting the yarn upstream of the region in which it orbits the rotary yarn package.

2. A process as claimed in claim 1, wherein the fluid is air.

3. A process as claimed in claim 1 or 2, wherein the surface appearance of the yarn is altered by varying the relative contributions of twist insertion by ring spinning and fluid jet twisting.

4. A process as claimed in any one of the preceding claims, wherein a core filament is inserted upstream of the fluid jet twisting so as to produce a core yarn.

5. Ring spinning apparatus comprising a rotary spindle coaxial with a ring and a yarn guide through which yarn is fed in use to orbit the growing yarn package, a feed mechanism from which yarn is fed on a feed path to said guide, and fluid jet twisting means on said feed path.

6. Apparatus as claimed in claim 5, wherein the fluid jet twisting means is an air jet twister.

7. Apparatus as claimed in claim 6, wherein the air jet twister comprises a yarn passageway surrounded by air nozzles arranged to direct compressed air tangentially into the passageway in the direction of yarn travel.

8. Apparatus as claimed in any one of claims 5 to 7, further comprising means for inserting a core filament upstream of the fluid jet twisting means.