GB2394938A

GB2394938A - A method for covering a core yarn with a cover yarn

Info

Publication number: GB2394938A
Application number: GB0324111A
Authority: GB
Inventors: Thomas Leslie Patterson
Original assignee: Adria Ltd
Current assignee: Adria Ltd
Priority date: 2002-10-19
Filing date: 2003-10-15
Publication date: 2004-05-12
Also published as: WO2004035890A1; AU2003271949A1; GB0224347D0; GB0324111D0

Abstract

An apparatus 10 for covering a core yarn 14 with a cover yarn 12 includes a mounting assembly 22 for mounting a package 16 of core yarn such that the core yarn package is fixed against rotation and means for guiding a cover yarn 12 along a path which on rotation about an axis defines an envelope which surrounds the core yarn package 16. The core yarn 14 may be drawn off along the axis of rotation of the cover yarn path so that when the core yarn 14 intercepts the envelope it is covered by the cover yarn 12. The apparatus includes an upstream guide 50 which defines an upstream end of the cover yarn path and a downstream guide member 52 located on an opposite side of the core yarn package 16 from the upstream guide 50, the downstream guide member 52 extending outwardly from the axis of rotation of the cover yarn path and being rotatable about that axis and the cover yarn path extending from the upstream guide 50 to a radially outer part of the downstream guide member 52 and then inwardly to the core yarn 14. Preferably the downstream guide member 52 is elongate. The apparatus may include means for adjusting the position of the upstream guide 50 independent upon the speed of rotation of the downstream guide member 52.

Description

Yarn Covering Apparatus and Method The present invention concerns

improvements in or relating to apparatus and methods for winding a cover yarn or yarns around a core yarn. The method and apparatus is particularly, but not exclusively, concerned with yarns ultimately 5 to be knitted into hosiery, for example ladies' stockings and tights.

The relatively small diameter of the core and covering yarns and the relative fragility of the yarns gives rise to certain difficulties. Prior apparatus and methods have overcome some of these difficulties but certain disadvantages remain. 10 In one presently accepted apparatus, cover yarn is pre-wound on to a specially shaped, doubled flanged bobbin which is mounted on a hollow spindle positioned between a core yarn supply and a core yarn take-up with the core yarn passing through the hollow spindle. Cover yarn is wound around the core yarn after it has passed through the hollow spindle by rotating the flanged 15 bobbin. The maximum rotational speed of the bobbin is restricted by virtue of its mass and dimensions and this means that only a limited amount of cover yarn can be would on to the core yarn if it is to achieve an acceptable rotational speed. The relatively small amount of cover yarn on the bobbin means that the apparatus has to be stopped frequently to change bobbins. The length of 20 covered yarn taken up on the core yarn take-up is relatively short and, in practical terms, perhaps a quarter of the length of yarn normally carried by the yarn spools utilised on commercial knitting machines. To provide a spool of yarn for a commercial knitting machine it is therefore preferable to rewind the covered core yarn from several yarn take-up spools. Normally the contents of at least four 25 take-up spools are wound onto the knitting machine package and this means that, in addition to the inconvenience of providing re-spooling machinery, providing man power to operate this re-spooling machinery and the replacement of bobbins in the covering machinery, the yarn supplied to the knitting machine includes knots at the joints between lengths.

According to the invention there is provided an apparatus for covering a core yarn with a cover yarn, the apparatus including: means for mounting a package of core yarn such that the core yarn is fixed against rotation; 5 means for guiding a cover yarn along a path which on rotation about an axis defines an envelope which surrounds the core yarn package; means for drawing off the core yarn along the axis of rotation of the cover yarn path so that when the core yarn intercepts the envelope it is covered by the cover yarn; 10 upstream guide means defining an upstream end of the cover yarn path; and a downstream guide member located on an opposite side of the core yarn package from the upstream guide means, the guide member extending outwardly from the axis of rotation of the cover yarn path and being rotatable about that 15 axis, and the cover yarn path extending from the upstream guide means to a radially outer part of the downstream guide member and then inwardly to the core yarn.

The terms "upstream" and "downstream" refer to the general direction of travel of the cover yarn.

20 Preferably the apparatus further includes means for adjusting the position of the upstream guide means.

The upstream guide means is preferably moveable generally along the axis of rotation of the cover yarn path.

The apparatus may include means for altering the speed of rotation of the 25 guide member and means for altering the position of the upstream guide means in dependence upon the speed of rotation of the guide member.

The upstream guide means may be mounted on an elongate moveable member which is telescopically mounted within a fixed member. The moveable member may be telescopically moveable relative to the fixed member generally

along the axis of rotation of the cover yarn path. The moveable member is preferably hollow, and preferably the cover yarn is able to pass through the moveable member.

Preferably the apparatus includes a motor for rotating the guide member.

5 Preferably the motor is located downstream of the guide member. Preferably the motor includes a hollow centre through which the covered yarn may pass. The hollow centre of the motor is preferably aligned with the axis of rotation of the elongate guide member. The hollow centre may comprise a bore extending through a central shaft of the motor. The motor preferably drives the rotation of 10 the guide member directly. The motor preferably uses a power of less than 0.7 kW to rotate the guide member. Preferably the motor is linked to the upstream guide means, so that its movement may be controlled in dependence upon the speed of rotation of the motor.

The envelope defined by the rotation of the cover yarn path may be 15 generally conical or frustoconical. The upstream guide means preferably lies on the axis of rotation of the cover yarn path. The cover yarn path may lie at an angle of between 15 and 60 to its axis of rotation, the angle depending upon the position of the upstream guide means.

The cover yarn path may be free and the yarn unrestrained between the 20 upstream guide means and the radially outer part of the downstream guide member. The apparatus may include an enclosure surrounding the envelope defined by the rotating cover yarn, the enclosure optionally providing some external restraint to the yarn. The enclosure is preferably substantially conical or frustoconical and is preferably substantially transparent. Preferably no 25 restraining means are provided for the cover yarn on its inner side.

Preferably the means for drawing off the core yarn includes means for drawing off the yarn in the downstream direction of the cover yarn.

Preferably the guide member is elongate, and may be substantially straight along its length.

The elongate guide member may extend outwardly from the axis of rotation of the cover yarn at an angle of between 70 and 110 to that axis.

Preferably the elongate guide member extends substantially perpendicularly to the axis of rotation of the cover yarn path. The guide member may extend 5 between 60mm and 120mm, and preferably between 80mm and 100mm, from the axis of rotation, and most preferably extends about 90mm from that axis.

The cover yarn path preferably extends inwardly along the elongate guide member. The guide member preferably includes a guide means for the cover yarn at its radially outer end and a guide means for the cover yarn at its radially 10 inner end. Each guide means preferably allows the cover yarn to pass loosely therethrough. The guide member may be hollow, allowing the cover yarn to pass therethrough. However, preferably the guide member is solid, the yarn path extending alongside the guide member.

The elongate guide member may be manufactured from a carbon fibre 15 composite material or for example from TUFNEL (trade mark).

The elongate guide member may be generally oval in shape when sectioned across its long axis. Alternatively the guide member may be approximately the shape of a diamond with truncated top and bottom corners.

The narrow ends of the oval or diamond may each taper to a feathered edge.

20 The narrow ends are preferably oriented at the front and rear of the guide member, as defined by its movement on rotation. The guide member may be of substantially constant section along its length or may taper towards its distal end, and is preferably substantially straight. The thickness of the elongate guide member across its narrower dimension may be between 1.5mm and 5mm and is 25 preferably between 1.5mm and 2.5mm. Upper and lower surfaces of the guide member are preferably of the same profile.

The apparatus may include a further rotatable elongate member, aligned with the elongate guide member and extending away from the axis of rotation of the cover yarn path in a direction diametrically opposite to that of the elongate 30 guide member. The further rotatable member may form part of a means for

guiding a further cover yarn of may constitute a counterbalance for the elongate guide member.

The apparatus may include means for guiding a plurality of cover yarns along independent paths, each of which on rotation about an axis defines an 5 envelope which surrounds the core yarn package. The means for guiding the further cover yarns may include the upstream guide means. The means for guiding the further cover yarns preferably includes further rotatable elongate guide members extending outwardly from the axis of rotation of the respective cover yarn envelope. Preferably the axes of rotation of all the cover yarn 10 envelopes are coincident.

Preferably the means for holding the core yarn package against rotation includes a magnet in the core yarn mounting means and a magnet on a fixed member spaced from the core yarn mounting means. Preferably the elongate guide member is located between the core yarn mounting means and the fixed 1 5 member.

Preferably a centre of the core yarn package is hollow, allowing core yarn from the core yarn package to be guided through the hollow centre to the inner end of the elongate rotatable member. Preferably the hollow centre lies on the axis of rotation of the cover yarn path.

20 Preferably a yarn tensioner is provided for the core yarn. The tensioner may include first and second annular discs mounted for axial movement over the surface of the hollow member and a spring for biasing the discs towards the end of the hollow member. The tensioner may further include an annular member resting on the disc closest to the end of the hollow member, the weight of said 25 annular member being variable to vary tension on yarn passing between the discs prior to it passing through the hollow member.

The apparatus may further include a cover yarn package. The cover yarn package may be located upstream of the upstream guide member. Alternatively the upstream guide member may be mounted on the cover yarn package.

The apparatus may further include a midstream guide member which generally surrounds the core yarn package and is positioned such that cover yarn extending directly between the upstream guide means and the radially outer part of the downstream guide member passes over the midstream guide member.

5 The apparatus may further include a heater for heating the cover yarn, the heater being located upstream of the point where the cover yarn envelope is intercepted by the core yarn.

According to a further aspect of the present invention there is provided a method of covering a core yarn with a cover yarn, the method including the steps 10 of: supplying a package of core yarn such that the core yarn is fixed against rotation; guiding a cover yarn along a path which on rotation about an axis defines an envelope which surrounds the core yarn package; and 15 drawing off the core yarn along the axis of rotation of the cover yarn path so that when the core yarn intercepts the envelope it is covered by the cover yarn; wherein the cover yarn path extends from an upstream guide means to a radially outer part of a downstream guide member located on an opposite side of 20 the core yarn package from the upstream guide means, the downstream guide member extending outwardly from the axis of rotation of the cover yarn path and being rotatable about that axis and the downstream guide member being rotated in order to rotate the cover yarn path and define the envelope.

Preferably the method includes the step of adjusting the position of the 25 upstream guide means in dependence upon the speed of rotation of the downstream guide member.

Preferably the upstream guide means is moved generally along the axis of rotation of the cover yarn.

Preferably as the speed of rotation of the downstream guide member increases the upstream guide means is moved towards the core yarn package, and vice versa.

Preferably the downstream guide member is rotated directly by a motor.

5 The motor is preferably located downstream of the elongate guide member and the cover yarn preferably passes through a centre of the motor. Preferably less than 0.7kW of power is used by the motor to rotate the guide member.

Preferably the position of the upstream guide means is controlled by the motor, in dependence upon the speed of the motor.

10 The envelope defined by rotation of the cover yarn path is preferably generally conical or frustoconical. Preferably the cover yarn is guided along its path such that it is free and unrestrained between the upstream guide means and the radially outer part of the elongate guide member. The cover yarn may be allowed to balloon outwardly away from a straight line path between the 15 upstream guide means and the elongate guide member.

Preferably the downstream guide member is elongate. The cover yarn may be guided from the radially outer part of the elongate guide member inwardly to meet the core yarn. The core yarn may be guided at an angle of between 70 and 110 to the axis of rotation of the cover yarn path. Preferably 20 the cover yarn is guided at an angle of about 90 to the axis of rotation of the cover yarn path and preferably the cover yarn path is angled at about 90 to the core yarn path at the point where the two paths meet. Preferably the cover yarn is guided loosely through guide means.

Preferably the cover yarn path is rotated in a direction which corresponds 25 with the direction of drawing off of core yarn from the core yarn package.

The method may include the step of guiding a plurality of cover yarns long with independent paths, each of which on rotation about an axis defines an envelope which surrounds the core yarn package.

Preferably the core yarn from the core yarn passage is guided through a hollow centre of the core yarn package. Preferably the core yarn is guided along a path which coincides with the axis of rotation of the cover yarn path.

The method may further include the step of heating the cover yarn in a 5 region upstream of the point where the cover yarn envelope is intercepted by the core yarn, for causing texturing of the cover yarn as it cover the core yarn.

An embodiment of the present invention will now be described by way of example only with reference to the accompanying drawings in which: Fig. 1 is a diagrammatical sectional view of an apparatus for wrapping a 10 cover yarn around a core yarn, according to one embodiment of the invention; Fig. 2A is a plan view of a blade for use with the apparatus of Fig. 1; Fig. 2B is a plan view of an alternative blade for use with the apparatus of Fig. 1; Fig. 2C is a side view of the blade of Fig. 2B; 15 Fig 3 is a diagrammatic vertical section through the blade of Fig. 2bviewed in the direction of the arrow A; Fig. 4 is a diagrammatic sectional view of an apparatus for wrapping a cover yarn around a core yarn, according to a further embodiment of the invention; 20 Fig. 5 is a diagrammatic vertical section of a part of an apparatus according to a further embodiment of the invention; and Fig. 6 is a diagrammatic view of an apparatus according to a further embodiment of the invention.

Referring to Fig. 1, there is illustrated an apparatus 10 for wrapping a cover yarn 12 around a core yarn 14 to create a covered yarn 15. The core yarn 14 would normally be an elastic yarn, for example, LYCRA (registered trademark) and the cover yarn would generally be a substantially non elastic yarn of cotton, 5 polyester, etc. A package 16 of core yarn 14 comprises a non flanged cylindrical bobbin 18 on which the core yarn 14 is wound in a normal helical arrangement. The bobbin 18 is mounted on a mounting plate 20 by a bobbin mounting assembly 22. The assembly 22 mounts the bobbin 18 on the mounting plate 20 in such a 10 way that it prevents any tendency for the bobbin 18 to move over the mounting plate 20 as yarn is drawn off the bobbin 18.

The mounting assembly 22 further includes a hollow member 24 carrying a yarn tensioner 26 at its upper end. The yarn tensioner 26 includes a first ceramic disc 28 mounted for axial movement over the outer surface of the hollow 15 member 24 and spring biased towards the upper end of the member by a coil spring 34. A second ceramic disc 30 is also mounted for axial movement along the end of the hollow member 24. Core yarn 14 taken from a take-up point 32 on the periphery of the yarn package 16 is led between the discs 28 and 30 up the outer wall of the hollow member 24 and down through the hollow member 24 to a 20 guide 36. It will be realised that the coil spring 34 provides a shock absorbing affect to the yarn tensioner and tension in the yarn is determined by the weight of the upper ceramic disc 30 and an optional annular member (not illustrated) which may be rested on the upper disc 30.

The hollow member 24 lies on a central axis 54 of the apparatus, such 25 that core yarn may be drawn along that central axis.

Magnets 40 on the mounting plate 20 are located by corresponding magnets 42 fixed to the machine framework 44 to hold the core yarn package 16 and its mounting plate 20 against rotation. A space is provided between the machine framework 44 and the mounting plate 20, the function of which will be 30 described in more detail hereinafter.

An upstream end of a path for the cover yarn 12 is defined by an upstream guide 50. Upstream of the guide 50 is a means for providing cover yarn, which may be in the form of a cover yarn package (not illustrated).

Located on the opposite side of the core yarn package 16 from the 5 upstream guide 50, i.e. below the core yarn package 16 in the drawing, is an elongate guide member in the form of a blade 52. The blade lies in the space between the machine framework 44 and the mounting plate 20. The blade 52 extends outwardly from the central axis 54 of the apparatus 10 in a direction perpendicular to that central axis. The blade 52 may be rotated about that axis 10 as described in more detail below.

The blade 52 is provided with a radially outer guide 56, through which the cover yarn 12 may pass loosely. The blade 52 also includes a radially inner quide 58 located near to the central axis 54 of the apparatus 10.

The upstream guide 50 and the blade 52 define a path for the cover yarn, 15 this path being free and generally straight between the upstream guide 50 and the radially outer guide 56 on the blade 52. The path lies at an angle of about 25 to the central axis 54 of the apparatus. On rotation of the blade 52, the cover yarn path defines an envelope which surrounds the core yarn package 18, the envelope being generally conical in shape.

20 An counterweight 60 (which in this example is elongate) is provided diametrically opposite to and aligned with the blade 52, to balance the apparatus 10 on rotation of the blade.

The blade 52 is rotated by a motor 62, located downstream of the blade.

The motor 62 has a power of about 0.6kW and rotates at between 20,000 25 and 30,000 rpm. The motor includes a bore 64 extending through its central shaft. The bore and the axis of rotation of the motor 62 coincide with the central axis 54 of the apparatus 10. Covered yarn 15 may be drawn down through the bore 64 in the motor 62, as described below.

In operation, core yarn 14 is drawn off the core yarn package 16, through the yarn tensioning apparatus 26 and through the hollow member 24 down along the central axis 54 of the apparatus. The core yarn 14 passes through the guide 36 and continues down through the bore 64 and the motor 62.

5 Cover yarn 12 is drawn through the upstream guide 50 along a sloping path to the radially outer guide 56 on the blade 52 and subsequently radially inwardly to the inner guide 58. The cover yarn is then drawn down along the central axis 54 of the apparatus, through the bore 64 in the motor.

The motor 62 causes the blade 52 to rotate, this causing the cover yarn 10 path to rotate, thereby defining a generally conical envelope which surrounds the core yarn package 16. Although the envelope is generally conical, some ballooning' is allowed, whereby the centrifugal effect causes the yarn path to curve radially outwardly on rotation. This minimises the tendency for the yarn to break. The blade may rotate at speeds of up to about 25,000 rpm.

15 It will be appreciated that as the cover yarn envelope rotates, this causes the cover yarn to wrap around the core yarn 14, at a point 66 where the two yarns meet. The two yarns meet generally at right angles to one another and, as the yarns are drawn downwardly as viewed in the drawing, the cover yarn is wrapped around the core yarn in a generally helical manner.

20 Fig. 2A is a plan view of the blade 52, and Fig. 3 illustrates the blade 52 in section, the direction of movement of the blade on rotation being indicated by the arrows B. Preferred dimensions for the blade are given in Fig. 3.

It may be seen that the blade 52 is similar to an elongated diamond in sectional shape, and includes sharp knife edges 68. The knife edges 68 are 25 joined by upper and lower surfaces 70 and 72 which have corresponding profiles, in order to avoid any lift being generated. Flat central portions 75 of each surface have a width of about 5mm. The blade is about 80mm to 90mm long, is substantially straight and tapers from its proximal to its distal end, the width at the proximal end being about 19mm and at the distal end about 13mm. At its

proximal end, the blade merges smoothly into a hub 73, which has a diameter of about 34mm. The thickness of the blade and the hub is about 2mm. The blade is manufactured from a strong, light, non magnetic material such as TUFNEL (Trade Mark) or a carbon fibre material. The shape of the blade is aerodynamic, 5 such that the energy used in rotating the blade is minimised.

The blade 52 includes a ceramic eyelet 77, for loosely guiding the cover yarn. More than one eyelet may be provided to guide multiple yarns.

The counterweight 60 has a similar profile to the blade 52, but does not require the eyelet. However, one or more eyelets could be provided to balance 10 the blade.

An alternative blade arrangement is illustrated in Figs 2B and 2C. in this arrangement, the blade 52 is again mounted on a hub 73, but a horse shoe shaped counterweight 120 is also mounted on the hub 73, on the opposite side from the blade 52. The length of the blade 52, from the axis of rotation to its tip 15 is about 85 - 90mm, and the blade is substantially straight and tapers from its proximal to its distal end. The width of the blade at its distal end is about 8mm, and its thickness is about 2mm, along its entire length. This blade is also manufactured from a material such as TUFNEL or a carbon fibre material.

A generally cylindrical enclosure 76 is provided around the cylindrical 20 envelope defined by the rotation of the cover yarn 12. The enclosure may be positioned such that the cover yarn may touch it on rotation, or may be spaced sufficiently from the cover yarn 12 such that no contact occurs. The enclosure is preferably transparent.

Fig. 4 illustrates apparatus 10 according to a second embodiment of the 25 invention. The apparatus 10 is generally similar to that of the first embodiment, and corresponding reference numerals are used. However, the apparatus of Fig. 4 also includes means for altering the position of the upstream guide 50, as follows.

l The upstream guide 50 is mounted on a lower end of a cylinder 80. The cylinder is hollow and elongate and lies on the axis of rotation of the cover yarn path. The cylinder is telescopically mounted within a mounting member 82, such that the cylinder 80 may move up and down as viewed in the drawing relative to 5 the mounting member. This causes the upstream guide 50 to move closer to or further away from the core yarn package 16.

As in the Fig. 1 embodiment, in operation core yarn 14 is drawn off the core yarn package 16, through the yarn tensioning apparatus 26 and through the hollow member 24 down along the central axis 54 of the apparatus. The core 10 yarn 14 passes through the guide 36 and continues down through the bore 64 and the motor 62.

Cover yarn 12 is drawn through the upstream guide 50 along a sloping path to the radially outer guide 56 on the blade 52 and subsequently radially inwardly to the inner guide 58. The cover yarn is then drawn down along the axis 15 54 of the apparatus, through the bore 64 in the motor.

The motor 64 causes the blade 52 to rotate and as the cover yarn envelope rotates, this causes the cover yarn to wrap around the core yarn 14, at a point 66 where the two yarns meet, as described previously.

The position of the moveable cylinder 80 may be adjusted, so that the 20 upstream guide is always optimally positioned, as follows.

When the blade 52 is rotated relatively slowly, the yarn path between the upstream guide 50 and the radially outer guide 56 on the blade 52 tends to be generally straight (i.e. little ballooning occurs). This is illustrated by the broken line in the drawing. At such speeds, the guide 50 is located at the top of its range 25 of movement (indicated 50a in the drawing). It is necessary for the guide 50 to be located this high, in order that the cover yarn path avoids fouling against the core yarn package 16.

As the blade 52 rotates more quickly, the cover yarn starts to balloon outwardly due to centrifugal forces acting on it, and its path becomes curved.

This is illustrated by the unbroken line in the drawing. When this happens, the guide 50 may be lowered to a position nearer the core yarn package 16. The 5 guide member in this position is labelled 50b in the drawing. The cover yarn does not foul on the core yarn package 16, because of its ballooning.

The position of the guide 50 may be controlled directly from the motor 64, such that the guide is always as close to the core yarn package 16 as it can be, to avoid the cover yarn fouling on the core yarn package.

10 Using the above method, the energy efficiency of the apparatus is greatly improved. The apparatus avoids the long yarn paths at high speed which cause drag and reduce the efficiency of the apparatus.

Fig. 5 is a detail of an alternative embodiment of the invention. This embodiment is generally similar to the Figs. 1 and 6 embodiments, and 15 corresponding reference numerals are used. However, the Fig. 5 embodiment further includes an alternative means of improving the energy efficiency of the apparatus. A midstream guide member 90 is mounted so as to at least partially surround the core yarn package 16. The midstream guide member 90 includes a smooth, curved upper faced 92 which is in the way of the straight line path for the 20 cover yarn 12 between the upstream guide 50 and the radially outer guide 56 on the blade 52. The upstream guide member 90 is made of a smooth, low friction nylon material and when the blade 52 is rotated at low speeds, the cover yarn 12 may therefore slide freely over the midstream guide member 90.

As the speed of rotation of the blade 52 is increased, the cover yarn 12 25 balloons as described in relation to the Fig. 4 embodiment. This ballooning takes it away from the midstream guide member 90.

The provision of the midstream guide member 90 thus enables the upstream guide 50 to be positioned lower than would otherwise be the case and

avoids the long yarn paths at high speeds which cause drag and reduce the efficiency of the apparatus.

Referring to Fig. 6, there is illustrated a further embodiment of the invention. This embodiment enables the cover yarn to be textured as it is 5 wrapped around the core yarn.

In prior art systems, it is necessary for the cover yarn to be textured before

it is used in the yarn covering process. Texturing of a yarn prevents the individual yarn fibres from separating from one another. In the prior at, a texturing apparatus is provided completely separately from the yarn covering 10 apparatus, to form textured yarn from partially orientated yarn (POY) yarn. This POY is passed through a heater, over a cooling plateand then through a number of rollers which cause it to change direction rapidly and impart a "crimp" to the yarn. The yarn is also twisted. The textured yarn is then wound onto bobbins for subsequent use.

15 Referring to Fig. 6, the proposed novel arrangement includes a yarn covering apparatus 10 which may for example be as described in any of Figs. 1 to 5. The yarn covering apparatus 10 is shown in reduced size in Fig. 6. The arrangement further includes a heating unit 96, provided upstream of the upstream guide 50 of the apparatus 10. The apparatus works as follows.

20 Partially orientated yarn (POY) yarn is drawn from a POY package 98, through a guide 100 and through a drawing roller unit 102. The drawing roller unit 102 includes drawing rollers 104 which rotate in the general direction of yarn movement but sufficiently slowly to impart tension to the yarn. The yarn 12 is then passed through the heating unit 96 and subsequently to the covering 25 apparatus 10 where the pre-heated cover yarn is used to cover a core yarn 14 as described previously.

The applicants have found that surprisingly the apparatus as described above results in the cover yarn 12 effectively being textured as it passes through the covering apparatus and is wrapped around the core yarn.

The yarn cools and "sets" as it passes from the heating unit 96 to the blade. The throughput rate is about 50 meters per minute, which allows time for such cooling.

Incorporating texturing into the yarn covering process is highly 5 advantageous. Buying a separate texturing machine is very expensive and also involves additional associated costs such as higher energy consumption, labour handling costs and floor space requirement. The yarn produced by the new arrangement may also be of an improved quality due to the reduced material handling and storage requirements.

10 There is thus provided an apparatus which wraps cover yarn around core yarn in a manner which is energy efficient and which provides a good finished product. Various modifications may be made to the above described embodiment without departing from the scope of the invention. Instead of the counterweight 15 60, a second blade may be provided opposite the first blade 52. This blade could receive a second cover yarn, in order that two cover yarns may be wrapped simultaneously around a central core yarn. The cover yarns could for example be of different colours. Any number of blades 52 could be provided in order to wrap a plurality of cover yarns around a core yarn, provided that the blades 20 balance on the apparatus 10. Different means may be provided for adjusting the position of the upstream guide, and the blade 52 could be replaced with a disc, or other means for guiding the cover yarn inwardly.

Whilst endeavouring in the foregoing specification to draw attention to

those features of the invention believed to be of particular importance it should 25 be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. Apparatus for covering a core yarn with a cover yarn, the apparatus including: means for mounting a package of core yarn such that the core yarn 5 package is fixed against rotation; means for guiding a cover yarn along a path which on rotation about an axis defines an envelope which surrounds the core yarn package; means for drawing off the core yarn along the axis of rotation of the cover yarn path so that when the core yarn intercepts the envelope it is covered by the 10 cover yarn; upstream guide means defining an upstream end of the cover yarn path; and an elongate downstream guide member located on an opposite side of the core yarn package from the upstream guide means, the guide member extending 15 outwardly from the axis of rotation of the cover yarn path and being rotatable about that axis, and the cover yarn path extending from the upstream guide means to a radially outer part of the downstream guide member and then inwardly to the core yarn.

2. Apparatus according to Claim 1, wherein the guide member is 20 substantially straight along its length.

3. Apparatus according to Claim 1 or Claim 2, wherein the elongate guide member extends outwardly from the axis of rotation of the cover yarn at an angle of between 70 and 110 to that axis.

4. Apparatus according to Claim 3, wherein the elongate guide member 25 extends substantially perpendicularly to the axis of rotation of the cover yarn path.

5. Apparatus according to any preceding claim, wherein the guide member extends between 60mm and 120mm from the axis of rotation.

6. Apparatus according to any preceding claim, wherein the cover yarn path extends inwardly along the elongate guide member, and the guide member includes a guide means for the cover yarn at its radially outer end and a guide means for the cover yarn at its radially inner end.

5

7. Apparatus according to Claim 6, wherein each guide means allows the cover yarn to pass loosely therethrough.

8. Apparatus according to any preceding claim, wherein the elongate guide member is generally oval in shape when sectioned across its long axis.

9. Apparatus according to any of Claims 1 to 7, wherein the elongate guide

10 member is approximately the shape of a diamond with truncated top and bottom corners. 10. Apparatus according to Claim 8 or Claim 9, wherein the narrow ends of the oval or diamond each taper to a feathered edge and the narrow ends are oriented at the front and rear of the guide member, as defined by its movement 15 on rotation.

11. Apparatus according to any preceding claim, wherein upper and lower surfaces of the guide member are of the same profile.

12. Apparatus according to any preceding claim, wherein the elongate guide member tapers from its proximal to its distal end.

20

13. Apparatus according to any preceding claim, wherein the apparatus including a hub on which the elgonate guide member is mounted and the hub including a counterbalance located on an opposite side of the hub from the elongate guide member.

14. Apparatus according to any of Claims 1 to 12, wherein the apparatus 25 includes a further rotatable elongate member, aligned with the elongate guide member and extending away from the axis of rotation of the cover yarn path in a direction diametrically opposite to that of the elongate guide member, the further

rotatable member forming part of a means for guiding a further cover yarn or constituting a counterbalance for the elongate guide member.

15. Apparatus according to any preceding claim, wherein the apparatus includes means for guiding a plurality of cover yarns along independent paths, 5 each of which on rotation about an axis defines an envelope which surrounds the core yarn package.

16. Apparatus according to Claim 15, wherein the means for guiding the further cover yarns includes further rotatable elongate guide members extending outwardly from the axis of rotation of the respective cover yarn envelope, the 10 axes of rotation of all the cover yarn envelopes being coincident.

17. Apparatus according to any preceding claim, wherein the apparatus further includes means for adjusting the position of the upstream guide means.

18. Apparatus according to Claim 17, wherein the upstream guide means is moveable generally along the axis of rotation of the cover yarn path.

15

19. Apparatus according to Claim 17 or Claim 18, wherein the apparatus includes means for altering the speed of rotation of the guide member and means for altering the position of the upstream guide means in dependence upon the speed of rotation of the guide member.

20. Apparatus according to any of Claims 17 to 19, wherein the upstream 20 guide means is mounted on an elongate moveable member which is telescopically mounted within a fixed member. The moveable member may be telescopically moveable relative to the fixed member generally along the axis of rotation of the cover yarn path.

21. Apparatus according to Claim 20, wherein the moveable member is 25 hollow, and preferably the cover yarn is able to pass through the moveable member.

22. Apparatus according to any preceding claim, wherein the apparatus includes a motor for rotating the guide member, the motor being located downstream of the guide member.

23. Apparatus according to Claim 22, wherein the motor includes a hollow 5 centre through which the covered yarn may pass, the hollow centre of the motor being aligned with the axis of rotation of the elongate guide member.

24. Apparatus according to Claim 22 or Claim 23, wherein the motor drives the rotation of the guide member directly, and uses a power of less than 0.7 kW to rotate the guide member.

10

25. Apparatus according to any preceding claim, wherein the envelope defined by the rotation of the cover yarn path is generally conical or frustoconical, and the upstream guide means lies on the axis of rotation of the cover yarn path.

26. Apparatus according to Claim 25, wherein the cover yarn path lies at an angle of between 15 and 60 to its axis of rotation, the angle depending upon 15 the position of the upstream guide means.

27. Apparatus according to any preceding claim, wherein the cover yarn path is free and the yarn unrestrained between the upstream guide means and the radially outer part of the downstream guide member.

28. Apparatus according to any preceding claim, wherein the apparatus 20 includes an enclosure surrounding the envelope defined by the rotating cover yarn, the enclosure optionally providing some external restraint to the yarn.

29. Apparatus according to Claim 28, wherein the enclosure is substantially conical or frustoconical and is substantially transparent.

30. Apparatus according to any preceding claim, wherein no restraining 25 means are provided for the cover yarn on its inner side.

31. Apparatus according to any preceding claim, wherein the means for holding the core yarn package against rotation includes a magnet in the core yarn mounting means and a magnet on a fixed member spaced from the core yarn mounting means, the guide member being located between the core yarn 5 mounting means and the fixed member.

32. Apparatus according to any preceding claim, wherein a centre of the core yarn package is hollow and lies on the axis of rotation of the cover yarn path, allowing core yarn from the core yarn package to be guided through the hollow centre to the inner end of the rotatable member.

10

33. Apparatus according to Claim 2, wherein the apparatus includes a yarn tensioner for the core yarn, the tensioner including first and second annular discs mounted for axial movement over the surface of the hollow member, a spring for biasing the discs towards the end of the hollow member, and a further annular member resting on the disc closest to the end of the hollow member, the 15 weight of said annular member being variable to vary tension on yarn passing between the discs prior to it passing through the hollow member.

34. Apparatus according to any preceding claim, the apparatus further including a midstream guide member which generally surrounds the core yarn package and is positioned such that cover yarn extending directly between the 20 upstream guide means and the radially outer part of the downstream guide member passes over the midstream guide member.

35. Apparatus according to Claim 34, wherein the midstream guide member is of a low friction nylon material.

36. Apparatus according to Claim 34 or Claim 35, wherein the midstream 25 guide member is generally cylindrical for surrounding the core yarn package and includes a curved upper surface over which the cover yarn may pass.

37. Apparatus according to any of Claims 34 to 36 wherein the positions of the upstream guide means, the radially outer part of the downstream guide member

and the midstream guide member are such that the cover yarn contacts the midstream guide member when the downstream guide member is rotated relatively slowly and balloons out of contact with the midstream guide member when the downstream guide member is rotated relatively fast.

5

38. Apparatus according to claim 37, wherein the relatively slow speed is less than about 15,000 rpm and the relatively high speed is more than about 20,000 rpm.

39. Apparatus according to any preceding claim, the apparatus further including a heater for heating the cover yarn, the heater being located upstream 10 of the point where the cover yarn envelope is intercepted by the core yarn.

40. Apparatus according to Claim 39, wherein the heater is located upstream of the upstream guide means.

41. Apparatus according to Claim 39 or Claim 40, wherein the heater is capable of reaching temperatures of at least 200 C and is at least 1.5m long.

15

42. A method of covering a core yarn with a cover yarn, the method including the steps of: supplying a package of core yarn such that the core yarn package is fixed against rotation; guiding a cover yarn along a path which on rotation about an axis defines 20 an envelope which surrounds the core yarn package; and drawing off the core yarn along the axis of rotation of the cover yarn path so that when the core yarn intercepts the envelope it is covered by the cover yarn; wherein the cover yarn path extends from an upstream guide means to a 25 radially outer part of a downstream guide member located on an opposite side of the core yarn package from the upstream guide means, the downstream guide member extending outwardly from the axis of rotation of the cover yarn path and being rotatable about that axis and the downstream guide member being rotated in order to rotate the cover yarn path and define the envelope.

43. A method according to Claim 42, wherein the method includes the step of adjusting the position of the upstream guide means in dependence upon the speed of rotation of the downstream guide member.

44. A method according to Claim 43, wherein the upstream guide means is 5 moved generally along the axis of rotation of the cover yarn and as the speed of rotation of the downstream guide member increases the upstream guide means is moved towards the core yarn package, and vice versa.

45. A method according to Claim 43 or Claim 44, wherein the downstream guide member is rotated directly by a motor located downstream of the elongate 10 guide member, the cover yarn passing through a centre of the motor.

46. A method according to Claim 45, wherein the position of the upstream guide means is controlled by the motor, in dependence upon the speed of the motor.

47. A method according to any of Claims 42 to 46, wherein the envelope 15 defined by rotation of the cover yarn path is generally conical or frustoconical and the cover yarn is guided along its path such that it is free and unrestrained between the upstream guide means and the radially outer part of the elongate guide member.

48. A method according to any of Claims 42 to 47, wherein the cover yarn 20 path is rotated in a direction which corresponds with the direction of drawing off of core yarn from the core yarn package.

49. A method according to any of Claims 42 to 48, the method further including the step of heating the cover yarn in a region upstream of the point where the cover yarn envelope is intercepted by the core yarn, for causing 25 texturing of the cover yarn as it covers the core yarn.

50. Apparatus substantially as herein described with reference to any of the accompanying drawings.

51. A method substantially as herein described with reference to any of the accompanying drawings.

52. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same 5 invention as any of the preceding claims.