GB2077307A

GB2077307A - Fancy Yarn

Info

Publication number: GB2077307A
Application number: GB8018833A
Authority: GB
Original assignee: Wool Development International Ltd
Current assignee: Wool Development International Ltd
Priority date: 1980-06-09
Filing date: 1980-06-09
Publication date: 1981-12-16
Also published as: GB2077307B

Abstract

A method of producing a fancy yarn on a spinning frame having front drafting rollers 12, 14 and a twisting spindle which comprises underfeeding a foundation yarn 30 to the twisting spindle and feeding an effect yarn 38 from the front drafting rollers 12, 14 to meet the foundation yarn 30 at a convergence point 40 whereby both the effect and foundation yarn are spun onto the twisting spindle as a fancy yarn. This may be done by having a foundation yarn feed roller 20 contacting and being driven by one of the front drafting rollers 12. The feed roller 20 has a section of smaller diameter 22 around which the foundation yarn 30 is passed. <IMAGE>

Description

SPECIFICATION Fancy Yarn This invention relates to a method of producing fancy yarn on a spinning frame and to an apparatus therefor.

Fancy yarns are normally made on a fancy twisting frame on which a foundation and one or more effect yarns are twisted together in such a way as to produce irregular, or fancy, yarns. Fancy twisting frames are ordinarily equipped with such items as extra sets of rollers, with devices to accelerate or intermittently stop one set of rollers with respect to the rest. Many types of fancy yarn are available, e.g. slub, loop, knop, bouclé or stripe yarn. Our British Patent Nos. 1 ,46 1 ,783, 1,479,736, and 1,530,477 disclose methods of producing knop, slub or loop yarns respectively on conventional spinning frames with only minor modifications, thus omitting a processing step and thereby effecting economies of production.

(Fancy yarn terms are explained in "Textile Terms and Definitions", 7th edition, published by the Textile Institute).

The present invention seeks to provide a method and apparatus which can produce in a simple manner a wide range of fancy yarn on conventional worsted or woolen spinning equipment.

According to the present invention there is provide a method of producing a fancy yarn on a spinning frame having front drafting rollers and a twisting spindle which comprises underfeeding and a foundation yarn to the twisting spindle and feeding an effect yarn from the front drafting rollers to meet the foundation yarn at a convergence point whereby both effect and foundation are spun onto the twisting spindle as a fancy yarn.

By "underfeeding" it is meant that the foundation yarn is fed at a lower linear speed than the effect yarn; and the amount of underfeeding determines largely the type of fancy yarn produced according to thsmethod of the invention.

The effect yarn meets the foundation yarn at a convergence point and forms an angle with the foundation yarn of at least 300, preferably at least 600. Ideally, the angle would be approximately 900 but the movement of both yarns towards the twisting spindle precludes this. Having a definite angle between the two yarns at the convergence point, rather than allowing the yarns to meet in a more or less side by side juxta position, allows spinning instabilities to occur about the convergence point thus giving rise to irregularities and hence fancy yarns.

The invention also comprises an apparatus for the production of a fancy yarn on a spinning frame having front drafting rollers and a twisting spindle which comprises a foundation yarn feed roller adapted to contact and be driven by one of the front drafting rollers, the feed roller having a section of smaller diameter than the rest of the roller, and the section of lesser diameter being adapted to grip the yarn passed thereabout.

The feed roller, being driven by one of the front drafting rollers, will have the same peripheral speed as the drafting rollers. However, the portion of lesser diameter will have a lower peripheral speed than the front drafting rollers and forward the foundation yarn at a speed less than the linear speed of the effect yarn which will be forwarded at the peripheral speed of the front drafting rollers. The difference in diameter between the main part of the feed roller and the part of lesser diameter, will determine the amount of underfeed, and to a great extent therefore also determine the form of yarn produced by the apparatus.

Preferably, the portion of the roller of lesser diameter is covered with an abrasive material, or may be roughened, so as to aid gripping the foundation yarn passed thereabout so that the foundation yarn may be fed with a controlled degree of underfeed against the pull of the winding-on device.

The foundation yarn may conveniently be stored on a package or creel adjacent the spinning machine and preferably passes through a tensioning device to the portion of the roller of lesser diameter. The provision of a tensioning device helps ensure that there is no slippage of the foundation yarn about the feed roller.

Preferably, a yarn guide is located adjacent the roller to ensure that the yarn does not trap itself as it passes about the roller. The foundation yarn used may be any form of yarn, staple or continuous filament, natural or synthetic. It is preferred to use a worsted spun wool yarn as the foundation.

As mentioned above, the amount of underfeed determines the form of fancy yarn produced. For a small degree of underfeed (that is in which the foundation yarn is fed at almost the same speed as the effect yarn) a corkscrew type of yarn can be produced. With high amounts of underfeed, for example with the effect yarn being fed twice as fast the foundation yarn, knop yarns are produced.

These yarns may be bound in the normal way, that is by doubling with a plain yarn on a twisting frame, in which case the corkscrew yarn will form a gimp yarn and the knop effect yarn will form a bouclé type yarn.

On many spinning frames, a bracket is provided for the fitting of a felt covered cleaning roller which rest on top of the front drafting rollers. In this case the feed roller of the invention may replace the cleaning roller. Where suitable brackets are not available they can easily be fitted to the spinning frame. A particular advantage of the apparatus of the invention is that a positive feed is maintained on both the foundation and the effect yarns thereby producing consistent results.

Furthermore, the device is extremely simple and can be fitted to and removed from equipment in a very short period of time and provides a reliable way of producing a wide range of fancy yarns on machinery otherwise confined to spinning plain yarn.

The effect yarn is in the process of being spun when it is applied to the foundation yarn as a method of the invention, and it must therefore be a staple fibre yarn, natural or synethetic, capable of being spun on a spinning frame. The method of the invention is applicable to all types of stable fibre spinning frames, including standard worsted and woolen spinning frames. Depending on the form of spinning used, the effect yarn will be fed to the front drafting rollers as a roving or slubbing and is converted to a yarn between the front drafting rollers and the twisting spindle.

A problem which arises when two or more strands are fed to a common twisting spindle to produce a composite yarn is that, should one of the strands accidently break, the remaining strand may continue to spin producing a faulty yarn. In order to prevent the production of such faulty yarns, it has been proposed to use so called "breakout" devices which, when one of two or more strands fed to a common twisting spindle breaks, effects breakout of the remaining strand or strands. Breakout devices as such are known, for example see U.K. Patent No. 1,543,885, but are primarily intended for use with plain yarns.

The devices are generally located in the yarn path and may be operated by deviations from this path.

Such devices are therefore not suitable for use with fancy yarns since the irregularities in the yarn can well produce unwanted accidental triggering of the breakout device.

Most spinning frames are provided with vacuum clearing tubes located usually below the front drafting roller which remove the roving or slubbing which continues to be fed from the drafting rollers when the spinning of the roving or slubbing breaks down.

According to the invention therefore there is further provided a device for preventing the spinning of a faulty singles yarn on a spinning frame which comprises a sensor located on or adjacent to the spinning frame vacuum clearing tube for detecting when a strand is passing into the vacuum clearing tube, and means responsive to the sensor for preventing a continued feed of the remaining strand or strands.

The sensor may comprise a simple pin located across the opening of the vacuum tube and connected by a suitable mechanical coupling, e.g.

a Bowden cable, to the means for stopping feed of the remaining strand or strands. When one of the strands breaks, it is sucked clear of the spinning zone by the vacuumclearing tube and will foul-the pin causing it to pivot and actuate the Bowden cable. The means for preventing the feed of the remaining strand or strands may comprise a simple spring loaded wedge which, triggered by the sensor, is inserted between the feed rollers of the remaining strand or strands thereby stopping the feed.

The invention will be described further, by way of example with reference to the accompanying drawings, in which: Figure 1 is a front elevational view of one section of a spinning frame embodying the apparatus of the invention; Figure 2 is a diagrammatic side elevational view corresponding to Figure 1; Figure 3 is a partial perspective view showing the yarn paths in more detail; Figure 4 is a diagrammatic side elevational view of the apparatus fitted with a breakout device according to the invention; and Figure 5 is a front elevational view corresponding to Figure 4.

Referring to Figures 1 to 3 of the drawings, there is shown one spinning head of a spinning frame the spinning head comprising an apron drafting system 10 having top and bottom front drafting rollers 12 and 14 and apron rollers 16.

The spinning head is provided with a lappet guide 18 and a twisting spindle (not shown). A foundation yarn feed roller 20 rests on the top roller 12 and is driven thereby. The roller 20 has a section 22 of lesser diameter than the rest of the roller 24, the section 22 is coated with a fine abrasive material and the portion 24 is covered with textured rubber to enable a good driving grip to be maintained with the top front drafting roller 12. The rollers 20 are held in position by means of brackets 26. Guide bars 28 are located adjacent each of the rollers 20.

A foundation yarn 30 is passed from a package or creel conveniently located adjacent the spinning head through a slot 32 in the guide bar 28 and around the portion 22 of the roller 20. The yarn passes through a second slot 34 in the guide bar 28 and hence over part of the surface of the top front drafting roller 12 and on through the lappet guide 1 8 to the twisting spindle. An effect slubbing or roving 36 passes through the apron drafting system and emerges from the front drafting rollers 12, 14, as an effect yarn 38 which meets the foundation yarn 30 at a convergence point 40.Since the effect yarn 38 is travelling faster than the foundation yarn 30, owing to the underfeed introduced by the smaller diameter portion 22 of the roller 20, spinning instability is set up and the convergence point oscillates (as shown by arrow A in Figure 2) causing irregularities or knops 42 to be formed on the combined yarn which is taken up on the twisting spindle.

The ratio of the diameter of the section 22 to the section 24 of the roller 20 determines the amount of underfeed which, as previously explained, helps determine the type of fancy yarn produced. A variety of rollers may be provided in which this ratio is varied and a set of such rollers will enable a wide variety of different yarns to be produced. Replacement of the rollers 20 is quick and simple, the roller which it is desired to replace being simply lifted off and replaced with the new roller.

More conveniently still still, the section 22 of the roller 20 may be made detachable from the section 24. Thus one section 24 need only be provided and a range of lesser diameter portions 22 may be attached or detached as required.

Referring now to Figures 4 and 5, it can be seen that the vacuum clearing tube 44 of the spinning frame is provided with a sensor in the form of a pin 46 positioned across the opening of the clearing tube 44. The pin 46 is connected to a Bowden cable 48 which in turn is connected to a triggering pin 50. A spring loaded wedge 52 is located adjacent the feed roller 20 and is held against the bias of a spring 54 by means of the triggering pin 50. Should a strand 38 break it will be cleared by the vacuum tube and will foul the pin 46 causing the latter to pivot downwardly (as seen in Figure 5) operating the Bowden cable 48 and removing the triggering pin 50 from the spring-loaded wedge 52.The latter will then be forced under the action of the spring 54 into the nip of the feed roller 24 and front drafting roller 12 lifting the former from the latter and preventing further feed of the foundation yarn 30.

Over-twisting of the yarn 30 leads to rapid breakage thereof.

As the pin pivots downwardly, the fibres which caused the movement are stripped off and cleared by the vacuum tube.

It can be seen that the apparatus described in relation to Figures 4 and 5 is designed to effect breakout of the foundation yarn only. This is because, in the method of the present invention, the foundation yarn is the stronger of the two strands 30, 38 which are being spun and therefore it is far more likely that the effect yarn 38 will be the yarn to break if breakage in fact occurs. Should the foundation yarn 30 break, in the system described it is most like that this will also lead to breakage of the effect yarn 38 since the latter is the weaker of the two. This will then activate the sensor and prevent further feed of the foundation yarn 30.In the spinning system of the invention described above, the foundation yarn passes over the top front roller 1 6 and is thus unlikely to be cleared by the vacuum clearing tube should it break, being more likely to wrap round the roller 1 6. However, the effect yarn breaking will operate the breakout device and serve to prevent further feed of the foundation yarn.

The following examples will illustrate the invention further.

Example 1 A worsted spinning frame using an SKF drafting system was provided with a foundation yarn feed roller 20 of the following dimensions.

The section 24 was 3.5 cm in diameter and 1.5 cm wide while the lesser diameter section 22 was 2 cm wide and 1.75 cm in diameter. The resulting underfeed was therefore 50%.

The draft of the spinning frame was set at 16.25 and the nominal twist was 200 turns per meter, Z twist. A worsted yarn of count 1/32 Nm with a twist of 490 turns per meter, Z twist was used as the foundation yarn 30 and the effect yarn was spun in a contrasting colour from 1,000 tex 64's quality worsted roving. Since the underfeed was 50%, the actual twist of the base was 400 turns per meter Z twist. The effect yarn overfed onto the foundation yarn producing a fancy yarn with random knops every 3 or 4 cm.

Example 2 The yarn described above in example 1 was doubled at 300 turns per meter S twist with a 1/32 Nm yarn similar to that used as the foundation yarn to produce a bouclé yarn.

Example 3 The feed roller described in Example 1 was replaced by a similar roller in which the section of lesser diameter 22 was 2 cm wide and 3 cm in diameter. The underfeed resulting from this was pprnximately 14.3%. Spinning was carried out as described in Example 1 but instead of knops forming the resulting fancy yarn was a corkscrew yarn with the heavier effect wrapped round the foundation yarn. The actual twist added to the foundation yarn in this case was approximately 233 turns per meter.

Example 4 The yarn produced in Example 3 was doubled on a twisting thread with a plain yarn similar to that used as the foundation yarn at 1 70 turns per meter through an S twist. A gimp yarn was produced.

Claims

1. A method of producing a fancy yarn on a spinning frame having front drafting rollers and a twisting spindle which comprises underfeeding a foundation yarn to the twisting spindle and feeding an effect yarn from the front drafting rollers to meet the foundation yarn at a convegence point, whereby both effect and foundation yarn are spun onto the twisting spindle as a fancy yarn.

2. A method as claimed in claim 1 in which the effect yarn forms an angle with the foundation yarn at the convergence point of at least 300.

3. A method as claimed in claim 2 in which the angle is at least 600.

4. A method as claimed in any one of claims 1 to 3 in which the degree of underfeed of the foundation yarn ranges from just less than the speed of the effect yarn to half the speed of the effect yarn.

5. A method as claimed in any one of claims 1 to 4 in which the foundation yarn is a staple fibre or continuous filament yarn, natural or synthetic.

6. A method as claimed in claim 5 in which the foundation yarn is a worsted spun wool yarn.

7. A method as claimed in any one of claims 1 to 6 in which the effect yarn is a staple fibre yarn, natural or synthetic.

8. A method as claimed in claim 7 in which the effect yarn is a wool worsted yarn or roving.

9. A method as claimed in any one of claims 1 to 8 in which a small degree of underfeed is employed and a corkscrew type yarn results.

10. A method as claimed in any one of claims 1 to 8 in which a high amount of underfeed is employed and a knop yarn is produced.

11. A method of producing a fancy yarn on a spinning frame substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

12. An apparatus for the production of a fancy yarn on a spinning frame having front drafting rollers and a twisting spindle which comprises a foundation yarn feed roller adapted to contact and be driven by one of the front drafting rollers, the feed roller having a section of smaller diameter than the rest of the roller, and the section of lesser diameter being adapted, in use, to grip the yarn passed thereabout

1 3. An apparatus as claimed in claim 12 in which the portion of the roller of lesser diameter is covered with an abrasive material, or is roughened, so as to aid gripping of the foundation yarn passed thereabout.

14. An apparatus as claimed in either of claims 12 or 13 in which a tensioning device for the foundation yarn is located prior to the portion of the roller of lesser diameter.

1 5. An apparatus as claimed in any one of claims 12 to 14 in which a foundation yarn guide is provided adjacent the roller to ensure that the yarn does not trap itself as it passes about the roller.

1 6. An apparatus for the production of fancy yarn on a spinning frame substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

1 7. A device for preventing the spinning of a faulty singles yarn on a spinning frame which comprises a sensor located on or adjacent to the spinning frame vacuum clearing tube for detecting when a strand is passing into the vacuum clearing tube, and means responsive to the sensor for preventing a continued feed of the remaining strand or strands.

18. A device as claimed in claim 17 in which the sensor is a pin located across the opening of the vacuum tube connected by a mechanical coupling to the means for stopping the remaining strand or strands.

1 9. A device as claimed in claim 18 in which the mechanical coupling comprises a Bowden cable.

20. An apparatus as claimed in any one of claims 17 to 19 in which the means for preventing the feed of the remaining strand or strands comprises a spring loaded wedge which, triggered by the sensor, is inserted between the feed rollers of the remaining strand or strands thereby stopping the feed.

21. A device for preventing the spinning of faulty singles yarn on a spinning frame substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.