WO2004053215A1

WO2004053215A1 - Condensation device and method applicable to ring-type spinning machines with or without spinning head

Info

Publication number: WO2004053215A1
Application number: PCT/IB2003/004146
Authority: WO
Inventors: Mario Mazzone; Roberto Gaudino
Original assignee: OFFICINE GAUDINO SpA
Current assignee: OFFICINE GAUDINO SpA
Priority date: 2002-12-12
Filing date: 2003-09-24
Publication date: 2004-06-24
Anticipated expiration: 2005-06-12
Also published as: ITUD20020259A1; EP1616049A1; AU2003263471A1

Abstract

Condensation device applicable to spinning machines (100) for high quality, limited pile yarns, whether they consist of natural, synthetic or mixed textile fibers, wherein the spinning machines are fed by rovings (11) and each include a distinct stretching assembly (12) with relative spindles (19). The condensation device comprises at least a pair of supplementary cylinders (21a, 21b), located between the stretching assembly (12) and the spindle (19), and able to define a free segment (30) in the roving (11) passing between the stretching assembly (12) and the spindle (19) wherein a false twist at zero point is imparted.

Description

"CONDENSATION DEVICE MD METHOD APPLICABLE TO RING-TYPE

SPINNING MACHINES WITH OR WITHOUT SPINNING HEAD"

* * * * *

FIELD OF THE INVENTION The present invention concerns a device and the relative method for spinning high quality, limited pile yarns, whether they be yarns obtained from synthetic, natural or mixed fibers. The invention is applied particularly, but not exclusively, in obtaining yarns with_. a metric number from about 10 to 100 and more.

BACKGROUND OF THE INVENTION It is known that in the step of obtaining yarns, a roving of parallel fibers is processed into a yarn in an appropriate spinning machine. In such spinning machines the roving is first of all subjected to a stretching step, in an appropriate stretching assembly or unit, or rolling assembly, before being twisted and wound onto the spools.

Various stretching assemblies have been known for many decades now, some of which not only stretch the bundle of fibers but also are provided with devices that perform a "false twist" on the bundle of fibers; by false twist we mean a twist imparted by the device on the bundle of fibers first in one direction and then in the other, so that the actual twist imparted is nil, that is, false.

Moreover, this false twist can also be at "zero point", that is, it can be imparted by the same pair of cylinders that unwinds the yarn, so that there is no distance between the point at which the false twist is imparted and the point wherein the yarn is drawn.

Two stretching assemblies, inside which there are devices which also perform a false twist, both normal and at zero point, are shown in the German patents DE-C-502216 and DE-C-889573. In these prior art documents, whose declared purpose is to stretch and twist at the same time a roving of fibers, each false twist device is present only inside the stretching assembly, which thus performs both the stretching proper and also a false twist.

In particular cases, between the stretching step and the twisting step, there is a condensation step, that is, a step that serves to reduce the gripping triangle of the fibers, which is created when torsion is imparted, and in this way reduce the tension caused by the torsion on the lateral fibers of the triangle, consequently improving the quality of the resultant yarn, and particularly on its pile .

Until now, systems of a pneumatic type have been used for the condensation step, located immediately downstream of the stretching assembly that stretches the strip and before the spindle on which the yarn is wound.

These known condensation devices have the disadvantage, however, that they require constant cleaning and maintenance. Moreover, they might not provide a constant quality in the event that the pneumatic unit were blocked with dust or other material and hence they do not guarantee a constant quality from spindle to spindle. Such condensers are also particularly expensive to make. Applicant has devised, designed, tested and embodied the present invention to overcome these shortcomings of the state of the art and to obtain other advantages, and particularly to obtain a yarn with constant quality.

SUMMARY OF THE INVENTION The present invention is set forth and characterized in the main claims, while the dependent claims describe other innovative characteristics of the present invention. The purpose of the present invention is to achieve a mechanical condensation device for yarns, arranged not in the stretching assembly but downstream thereof, and also to perfect the relative method, which will allow to induce in the roving, after the stretching assembly and before the field of torsion, a false twist at zero point, wherein the torsion applied between the outlet from the stretching field and the mechanical device is cancelled in the field of torsion. This is in order to "capture" the point wherein the false twist is imparted, because at that point the fibers are more "condensed", that is, the triangle presented for torsion which rises from the spindle at outlet from the gripping, is smaller than what it would otherwise be.

By yarn we mean any textile yarn consisting of any type of fiber, whether it be natural, such as wool, cotton, hemp, jute, linen, etc., or synthetic or a mix of natural- synthetic .

In accordance with this purpose, the device according to the present invention comprises at least a pair of supplementary cylinders able to apply a false twist to the roving, already stretched by the stretching assembly arranged upstream, before the proper twist is performed.

According to a first embodiment, the pair of supplementary cylinders is located immediately downstream of the stretching assembly, or rolling assembly, at a desired distance.

To be more exact, to apply the false twist to the roving, the pair of supplementary cylinders comprises a drawing cylinder, which can be both commanded and motorized, and a pressure cylinder which is arranged on the side opposite the roving, with respect to the drawing cylinder, and is rotatable idle on its own axis. The axis of rotation of the pressure cylinder is inclined by a pre- determined angle with respect to the axis of rotation of the corresponding drawing cylinder of the pair of supplementary cylinders.

The pressure cylinder is anchored to the frame of the machine and can have its own movement means .

According to a variant, the pressure cylinder is anchored to the arm that drives the stretching assembly.

The peripheral speed of the drawing cylinder of the pair of supplementary cylinders is equal to or less than the outlet speed of the roving from the rolling assembly.

The free length of the roving in the segment where the false twist is imparted is between 25 and 120 mm; in the case of wool with fibers of an average length of between 60 and 70 mm and with a fineness from 17 to 24 μ, the free length is between 60 and 80 mm.

To impart the false twist, the invention provides that the axis of the pressure cylinder has a determinate angle with respect to the axis of the drawing cylinder. Said angle is between 2° and 10°, advantageously, in the case of the wool cited above, 4°-5°.

According to the invention, the value of this angle is fixed for a particular calibration.

According to a variant, said angle can be regulated, so it can be adapted to various calibrations. The pressure cylinder acts on the roving, compressing it against the drawing cylinder with an elastic force of a desired entity; said elastic force is obtained by means of spring means .

According to a variant, said elastic force is obtained with pneumatic or mixed means.

The elastic force is between 1 and 15 kg, advantageously, in the case of the wool cited above, it is about 3 kg, in the event that the surface of the pressure cylinder is made of rubber with a hardness of between 65 and 90 shore.

According to the invention, the elastic force can be regulated. According to a variant, the elastic force is variable. According to a variant, both the drawing cylinder of the supplementary pair, and the corresponding pressure cylinder, can be divided into two or more segments. In this case the pressure cylinder can be replaced by a plurality of pressure rollers, mounted rotatable on corresponding axes, all inclined by the above angle with respect to the axis of rotation of the drawing cylinder. In this specific case, the different pressure rollers can have a single axis of rotation, or each one can have its own axis of rotation arranged inclined on reciprocally opposite sides with respect to the axis of rotation of the driven cylinder. BRIEF DESCRIPTION OF THE DRAWINGS These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example, with reference to the attached drawings wherein :

- fig. 1 is a general diagram of a condensation device according to the present invention; - fig. 2 shows schematically the behavior of the roving in the segment between the last pair of cylinders of the stretching assembly and the pair of supplementary cylinders of the device in fig. 1;

- fig. 3 shows an enlarged detail of the pair of supplementary cylinders in fig. 1;

- fig. 4a shows a variant of the pair of supplementary cylinders in fig. 3 ;

- fig. 4b shows another variant of the pair of supplementary cylinders in fig. 3. DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF EMBODIMENT

OF THE INVENTION With reference to fig. 1, a condensation device 10 according to the present invention is shown applied in a ring-type spinning machine 100, with or without spinning head, of a known type and comprising a stretching assembly or rolling assembly 12 for a roving 11 which will subsequently become a yarn lib after condensation. The rolling assembly 12 is substantially of a known type and comprises, in this case, a plurality of rolling cylinders 15, in this case three (15a, 15b; 15c, 15d; 15e, 15f) . The stretching assembly shown here as an example is of the so- called "Casablanca" type, but any other known stretching assembly can be used, with or without a false twist device inside, such as for example those shown in the German patents DE-C-502216 and DE-C-889573 cited above.

The cylinders 15a, 15c and 15e are drawing cylinders and can be both commanded and motorized, while the cylinders 15b, 15d and 15f in this case are mounted free to rotate on pins 16a of a supporting arm 16.

Downstream of the rolling assembly 12 there is a relative spindle 19, of a known type, in this case associated with the guide loop 20. According to a characteristic feature of the present invention, the condensation device 10 is arranged immediately downstream of the last pair of cylinders 15a, 15b of the rolling assembly 12 and before the loop 20 and comprises a pair of supplementary cylinders 21a and 21b. The condensation device 10 and the stretching assembly 12 define the segment 30 wherein the false twist at zero point is imparted.

The embodiment as described heretofore also applies in the case that the rolling assembly 12 consists of a stretching device under false twist (see the various known systems applied in the field of carded spinning) .

The free length (fig. 2) of the roving 11 in the segment 30 wherein the false twist is imparted, in the case of the type of wool cited above, is between about 60 and 80 mm.

The characteristic of the pressure cylinder 21b is that its axis of rotation 25 is inclined by an angle oc with respect to the axis of rotation 22 of the drawing cylinder

21a.

The peripheral speed of the drawing cylinder 21a is in this case equal to that of the drawing cylinder 15a of the rolling assembly 12. Fig. 2 shows the behavior of the roving 11 in the case where the peripheral speed of the drawing cylinder 21a is equal to or less than that of the cylinder 15a.

According to the embodiment shown in fig. 3, the individual pressure cylinder 21b consists of two pressure rollers 121b conformed in pairs lying on a single axis 25 which has an angle with respect to the axis of the drawing cylinder 21a.

According to the two variants shown in figs. 4a and

4b, the two pressure rollers 121b are mounted rotatable on corresponding axes 25, each inclined by the angle with respect to the axis of rotation 22, but on reciprocally opposite sides. To be more exact, in figs. 4a and 4b the inclination is downwards, but it can also be upwards. In the case of fig. 4a, the top 32 lies on the axis 22 of the drawing cylinder 21a. In the case of fig. 4b the top 32 is displaced with respect to the axis 22 of the drawing cylinder 21a so that the axes 25 and 22 cross at about the median line of each pressure roller 121b. It is clear, however, that modifications and/or additions of parts can be made to the device 10 as described heretofore, without departing from the field and scope of the present invention. It is also clear that, although the present invention has been described with reference to specific examples, a person of skill in the art shall certainly be able to achieve other equivalent forms of the device and/or method to obtain yarns with less pile, all of which shall come within the field and scope of the present invention.

Claims

1. Condensation device applicable to spinning machines for limited pile, high quality yarns, whether they consist of natural, synthetic or mixed textile fibers, wherein said spinning machines are fed from rovings and each include a distinct stretching assembly (12) with relative spindles (19) , characterized in that it comprises at least a pair of supplementary cylinders (21a, 21b) , located between the stretching assembly (12) and the spindle (19) and able to define a free segment (30) in the roving passing between the stretching assembly (12) and the spindle (19) wherein a false twist at zero point is imparted.

2. Device as in claim 1, characterized in that said pair of supplementary cylinders (21a, 21b) is located immediately downstream of the stretching assembly (12) and the free segment (30) is defined between said pair of supplementary cylinders (21a, 21b) and the pair of outlet cylinders (15a, 15b) of the stretching assembly (12).

3. Device as in any claim hereinbefore, characterized in that said pair of supplementary cylinders (21a, 21b) includes a drawing cylinder (21a), commanded and/or motorized, and a pressure cylinder (21b) elastically pressed towards said drawing cylinder (21a) with a force of between 1 and 15 kg.

4. Device as in any claim hereinbefore, characterized in that the axis (22) of the drawing cylinder (21a) and the axis (25) of the pressure cylinder (21b) define an angle ( ) of between 2° and 10°.

5. Device as in any claim hereinbefore, characterized in that the axis (22) of the drawing cylinder (21a) and the axis (25) of the pressure cylinder (21b) cross outside the pressure cylinder (21b) .

6. Device as in any claim hereinbefore, characterized in that the axis (22) of the drawing cylinder (21a) and the axis (25) of the pressure cylinder (21b) cross within the length of the pressure cylinder (21b) .

7. Device as in any claim hereinbefore, characterized in that the length of said free segment (30) of the roving

(11) wherein the false twist is imparted is between 25 and 120 mm.

8. Device as in any claim hereinbefore, characterized in that the peripheral speed of the drawing cylinder (21a) of said pair of supplementary cylinders (21a, 21b) is equal to the peripheral speed of the outlet cylinders (15a, 15b) of said stretching assembly (12).

9. Device as in any claim from 1 to 7 inclusive, characterized in that that the peripheral speed of the drawing cylinder (21a) of said pair of supplementary cylinders (21a, 21b) is less than the peripheral speed of the outlet cylinders (15a, 15b) of said stretching assembly

(12) .

10. Device as in any claim hereinbefore, characterized in that the inclination of the axis (25) of said pressure cylinder (21b) with respect to the axis (22) of said drawing cylinder (21a) is fixed for at least one calibration of the spinning machines .

11. Device as in any claim hereinbefore, characterized in that the inclination of the axis (25) of said pressure cylinder (21b) with respect to the axis (22) of said drawing cylinder (21a) can be regulated.

12. Device as in any claim hereinbefore, characterized in that said pressure cylinder (21b) is carried by its own means.

13. Device as in any claim from 1 to 11 inclusive, characterized in that said pressure cylinder (21b) is carried by the arm (16) of the stretching assembly (12).

14. Condensation method to obtain a limited pile, high quality yarn in a spinning machine starting from a roving passing in a stretching assembly (12), said yarn having a metric number of between 10 and 100 and more, characterized in that after the roving has been worked in the stretching assembly (12) and before it goes into cooperation with the relative spindle (19), in a free segment (30) of the same roving, a false twist at zero point is imparted.

15. Method as in claim 14, characterized in that said free segment (30) is defined immediately downstream of the stretching assembly (12) and is between 25 and 120 mm.

16. Method as in claims 14 or 15, characterized in that the false twist is imparted by the cooperation of a pressure cylinder (21b) with a drawing cylinder (21a) of a condensation device (10), the axis of said pressure cylinder (21b) being angled with respect to the axis of said drawing cylinder (21a) .

17. Method as in any claim from 14 to 16 inclusive, characterized in that said pressure cylinder (21b) exerts an elastic pressure on the roving passing through of between 1 and 15 kg.

18. Method as in claim 17,- characterized in that the elastic pressure is variable.

19. Method as in claim 17, characterized in that said elastic pressure is adjustable.