Process for preparing "onde" or "compensina" yarns

Abstract

 A description is given of a process for preparing yarns (1) of the types called ondé or "compensina", consisting, respectively, of a twisted thread (2) and an untwisted thread (3), or two threads (2, 3) twisted in opposite directions to each other, doubled and additionally twisted after doubling by means of a single or double twist spindle (4), in which the said two threads (2, 3) are wound, respectively, on two winding members (5, 6) which are coaxial with each other and are mounted coaxially on a double twist spindle (4), and the said threads (2, 3) form the aforesaid ondé or "compensina" yarn (1), being doubled together immediately after the unwinding from the respective winding members (5, 6) and additionally twisted as a result of the passage through the said double twist spindle (4) in their travel towards a collecting bobbin (7).

Description

[0001] The present invention relates to the field of the textile industry, and more particularly to its sector concerned with the preparation of yarns of the types called "ondé" and "compensina".

[0002] These types of yarn are formed by joining together, by an operation known in the technical terminology of the art as "doubling", a previously twisted thread and another thread which is untwisted or is twisted in the opposite direction, and by imparting to the set of two threads thus produced an additional twist, by means of a single or double twist spindle, in the direction opposite that of the thread, within the pair, which was previously twisted to the greater extent.

[0003] In the present state of the art, the said two threads, twisted and untwisted, or twisted in opposite directions, are first joined together and collected on a bobbin, and are then given an additional twist by means of the aforementioned single or double twist spindle.

[0004] The operation of doubling the threads is very awkward and difficult to carry out because it is necessary to constantly control the tension imparted to each of the threads in such a way that, in spite of their different consistencies and their different physical characteristics of elasticity and reaction to the tension, their joining is uniform and meets the required standard of quality. Moreover, the doubling station obviously occupies space in the production plant, entailing corresponding costs.

[0005] The final, but not the least important, consideration is that, in order to enable the previously described doubling operation to be carried out between the threads, the twisted threads must in all cases be subjected, even if no dye is to be applied to them, to a steaming process which is necessary to distend the fibres and make the physical characteristics of the threads uniform throughout their length. The inventor of the present invention has devised a process which eliminates the steaming stage, and at the same time reduces the space occupied by the equipment required for forming yarns of the onde or "compensina" type. This is because he has devised a process in which the said two threads, twisted and untwisted (or twisted in opposite directions) are wound on winding members, such as bobbins and reels, arranged coaxially and mounted, also coaxially, on a double twist spindle with or without a hollow rod. The two threads are doubled and then twisted immediately after they have been unwound from the corresponding winding members, as a result of their passage through the said double twist spindle. Since the lengths of the two portions of thread between the points of their unwinding and their entry into the double twist spindle are very small, there is no alteration of the dimensions of the two portions of thread which might give rise to significant problems in respect of their proper doubling, and consequently no particular control has to be exerted over the tension applied to them.

[0006] Thus onde or "compensina" yarns are formed in a simple and economical way by means of a single forming station which is, above all, highly compact and occupies a very small space.

[0007] A more detailed description will now be given of a preferred example of an embodiment of the process according to the invention, the object of which is a process for preparing a thread of the onde or "compensina" type as described in the precharacterizing clause of the attached Claim 1, characterized by the characterizing part of the same claim.

[0008] To describe the aforesaid process more clearly, reference will also be made to the attached figure, which shows a diagram of equipment suitable for its implementation, which also forms part of the object of the invention. The case which will be described is that relating to a yarn of the onde type, in which one of the two threads is untwisted, but the process and the equipment for implementing it are also identical in the case of "compensina" yarns consisting of two threads with opposite twists doubled together. As shown in the figure, in equipment 10 suitable for carrying out the process according to the invention, a thread 2, previously twisted by known methods, is wound on a winding member consisting of a reel 5, and an untwisted thread 3 is wound on another winding member, consisting of a bobbin 6. The winding members, in other words the said reel 5 and the bobbin 6, are arranged coaxially and, in the example in question, are arranged one inside the other (but could also be positioned one outside the other in any other relative position in which they remain coaxial). The reel 5 and the bobbin 6 are then mounted, again coaxially, on a double twist spindle 4 (of the type with a hollow rod 4c in the arrangement shown).

[0009] The twisted thread 2 is unwound from the reel 5 and drawn by traction by known methods towards the interior of the said double twist spindle 4, being joined in a parallel way to the other, untwisted, thread 3 which is unwound in the same way from the said coaxial bobbin 6 and follows the same path. The two threads, arranged parallel to each other, pass through the double twist spindle 4, which imparts to them a twist which generally and preferably has a direction opposite that of the twist imparted previously to the said thread 2, which is the twisted thread in yarns of the onde type, or the more twisted thread in yarns of the "compensina" type. The threads 2 and 3, on passing through the double twist spindle 4, are therefore doubled and twisted simultaneously as a result of this passage during their travel towards a collecting bobbin 7, by means of which tension is applied to them by known methods. Thus a yarn 1 of the onde (or "compensina") type is formed in a single pass and collected on the aforesaid bobbin 7, by means of a fast and economical process and by means of equipment which, owing to its dimensions and the arrangement of the component parts, occupies a very small space. The object proposed by the inventor is therefore achieved.

Claims

1. Process for preparing yarns (1) of the type called onde or "compensina", consisting, respectively, of a twisted thread (2) and an untwisted thread (3), or of two threads (2, 3) twisted in opposite directions to each other, doubled together and additionally twisted after the doubling by means of a single or double twist spindle (4), characterized in that the said two threads (2, 3) are wound, respectively, on two winding members (5, 6) which are coaxial with each other and which, in turn, are mounted coaxially on a double twist spindle (4), and the said threads (2, 3) form the aforesaid onde or "compensina" yarn (1), being doubled together immediately after the unwinding from the respective winding members (5, 6) and being additionally twisted as a result of the passage through the said double twist spindle (4) in their travel towards a collecting bobbin (7).

2. Process according to Claim 1, in which the said double twist spindle (4) imparts to the said threads (2, 3), during their doubling, a twist whose direction is opposite that of the twist which was imparted previously to the more twisted thread (3).

3. Process according to one of the preceding claims, for the implementation of which a double twist spindle (4) with a hollow rod (4c) mounted below it is used.

4. Process according to one of the preceding claims, in which the unwinding of the more twisted thread (2) from the corresponding winding member (5) is facilitated by the use of unwinding devices.

5. Equipment (10) for preparing yarns (1) of the type called onde or "compensina", consisting, respectively, of a twisted thread (2) and an untwisted thread (3), or of two threads (2, 3) twisted in opposite directions to each other, doubled together and additionally twisted after the doubling by means of a single or double twist spindle (4), and then wound on a collecting bobbin (7), characterized in that the winding members (5, 6), on which the said two threads (2, 3) respectively are wound, are arranged coaxially with respect to each other and, in turn, mounted coaxially on a double twist spindle (4).

6. Equipment according to Claim 5, in which the said double twist spindle (4) is provided with a hollow rod (4c) positioned below it.

7. Equipment according to one of Claims 5 or 6, in which unwinding devices are connected to the winding member (5) on which the more twisted thread (2) are wound.

8. Equipment according to one of Claims 5, 6 or 7, in which the said threads (2, 3) are wound, respectively, on a reel (5) and a bobbin (6).

Drawing