Method Of And Apparatus For Spinning, Doubling And Twisting

Abstract

A method of and apparatus for spinning, doubling, and twisting in which fiber bands are discharged separately and at a given distance from each other from a drafting device, are combined in a free-floating point into a thread, and the thread is guided and calmed at a point between the free-floating point and the twisting member, while the imparted twist can unimpededly be transmitted between said free-floating point and the drafting device.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a method in which the spinning, doubling and twisting process is carried out in one single operation and on one single machine, and also relates to an apparatus for carrying out such method.

Several methods for combining the steps of spinning, doubling and twisting have become known. Thus, for instance, a method has been described for producing a yarn or thread mechanically reinforced in the interior thereof. In this method, at least two, substantially twist-free fiber bands are separately led from the so-called "pressure line" of the drafting apparatus of a spinning machine past a guiding means to a twisting point and there twisted to a yarn. The fiber bands are delivered by the drafting apparatus at such a distance with respect to each other that the spacing of each fiber band to the last "pressure line" of the drafting apparatus from the twisting point is less than the length of the longest fiber. The twisting point occurs where the forces as well as the moments produced in the yarn and in the fiber bands are in equilibrium. The guiding means is in the shape of a prism. The base surface of the prism is directed towards the delivery roller of the drafting apparatus and is larger than the distance between the fiber bands leaving the drafting apparatus. The two other surfaces form an obtuse angle with each other.

The fiber bands are passed around the rounded ends or corners of the base surface and have frictional contact therewith. The friction prevents the transmission of the rotation or twist from the twisting member to the pressure line in the drafting apparatus. The fiber bands are not "solid" along their twist-free path or have only a sharply reduced solidity and are also not positively guided. This results in a large number of thread breaks. Moreover, there exists the danger that the short fibers protruding from the fiber bands impact upon the prism, tear off further fibers from the fiber bands and thereby lead to accumulation of fibers and also to thread breakage. A well-known consequence of the imparting of a twist upon the fiber bands during the spinning or twisting process, is a very rough and uneven running of the thread, which extends beyond the thread guide to the "pressure line" of the drafting apparatus. The prism-shaped guiding element does also not contribute to the smooth running of the thread or fiber.

It will be evident from the above that the just described method does not result in a uniform twist and does not yield optimum running conditions for the thread. Since the spacing between the fiber bands at the exit of the drafting apparatus has to be selected depending on the fiber length, the prismatic guiding means has to be frequently exchanged and to be replaced by a prism of different size.

It is, therefore, an object of the present invention to provide a method of spinning, doubling and twisting of yarn in one continuous operation and on one single machine, which will overcome the above-mentioned drawbacks.

It is another object of the present invention to produce a yarn of a high quality, with as little cost in labor and capital as possible.

It is still another object of the present invention to provide a method and apparatus for carrying out the method, of the above-mentioned type, which will result in a very solid and uniform yarn, and in the finished textile fabric or the like in a product of high quality.

Still another object of the present invention consists in the provision of a method, and an apparatus for carrying out the method, which makes it possible to produce a modified yarn, the structure of which contains elements of a twisted yarn, without loosing the actual character of the yarn.

BRIEF DESCRIPTION OF THE DRAWING

The invention is illustrated by way of example in the attached drawings, in which:

FIG. 1 diagrammatically illustrates one method according to the present invention;

FIG. 2 is a diagrammatic illustration of the method according to the present invention in an apparatus with a "thread-calming" and thread-guiding element;

FIG. 3 is a side view of the arrangement according to FIG. 2;

FIG. 4 illustrates an embodiment according to the present invention with a changing thread calming and guiding element;

FIGS. 5 and 6 respectively illustrate further embodiments of an apparatus in accordance with the present invention with different forms of thread calming and guiding elements;

FIGS. 7 and 8 respectively illustrate a side and top view of a thread guiding element for use in connection with the present invention.

BRIEF SUMMARY OF THE INVENTION

The problems underlying the present invention as outlined above, have been solved by imparting upon the yarn simultaneously false twist and genuine twist by one and the same twisting element. Two or more fiber bands are fed at a certain preadjusted spacing with respect to each other into a drafting apparatus and are guided therethrough parallel to each other and discharged therefrom separately. In a free or free-floating point, the individual bands are led together and combined into a yarn. The point of junction serves as a twisting point in the sense of the well-known false-twisting method.

The just described method, therefore, practically combines two methods, namely a false-twisting method from the point of junction as an indirect-twist-imparting agent up to the clamping point of the pair of delivery rollers of the drafting apparatus, and a genuine twisting method from the twist member to the point of junction. The point of junction is formed freely, but its location depends on the amount of twist imparted upon the thread by the twisting member, on the distance of the fiber bands from each other, on the number of fibers or capillary threads in the bands, on the fineness of the fiber bands and on the twisting resistance. The fiber bands are free up to the clamping or pressure line of the drafting or delivery apparatus so that the twist imparted upon the thread can be extended beyond the point of junction in an unimpeded manner. As will be evident from the above, strength is given to the fiber bands immediately after leaving the drafting or delivery apparatus, by rotation or twisting. The feeding of the fiber bands to the drafting or delivery apparatus, is advantageously effected by means of a feeding element which is adjustable in a stepless manner, with adjusting slots and with nonpositive connecting means, The distance between the guiding eyelets of this element determines the distance of the fiber bands in the drafting apparatus and upon exit of the fiber bands therefrom. For purposes of calming and guiding the thread and also the fiber bands, preferably between the point of junction and the "balloon thread guide" a low-friction thread calming and guiding device with a recess for guiding the thread is adjustably provided in such a way that the device is still in frictional contact with the twisted thread in the top position of the balloon thread guide. The angle between the thread and a straight line connecting the "pressure line" and the thread guide is to be approximately zero. Furthermore, this device is to be provided approximately centrally with respect to the fiber bands so that the same form an isosceles triangle and so that the thread extends in a straight line.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Referring now to the drawing in detail, and FIG. 1 in particular, the fiber bands 1 shown therein are fed to a drafting or delivery apparatus of a spinning or twisting machine, only the lower delivery roller 3 of which is shown in FIG. 1. The fiber bands 1 are fed to the delivery roller 3 with a certain distance X with respect to each other, which distance is adjustable in a stepless manner by the feeding element 2 described in detail in connection with FIGS. 7 and 8. Upon leaving the so-called "clamping or pressure line" 3a between the delivery roller 3 and a further delivery roller 3' cooperating therewith, the fiber bands 4 are combined at the free point of junction 5 so as to form a yarn 6. The point of junction 5 is freely formed by the rotation or twist imparted upon the thread by means of a known spindle (not shown). The thread passes the thread guide 7 (balloon thread guide) and is subsequently wound upon a thread carrier in a well-known manner. The spacing between the individual fiber bands is preferably selected in such a way that the distance Y between the clamping or pressure line 3a of the pair of delivery rollers 3, 3' and the point of junction 5 is not larger than the average staple or fiber length, when the method is being applied for processing staple fibers.

The arrangement shown in FIG. 2 is slightly modified over that of FIG. 1 and includes a thread calming and guiding element 8 which is arranged between the point of junction 5 and the balloon thread guide 7 on an extended perpendicular line from the tip of the triangle formed by the fiber bands to the base line which is determined by the clamping or pressure line 3a between the pair of delivery rollers 3, 3'.

The thread calming and guiding element is preferably of cylindrical shape and is provided with a recess 12 arranged on the circumference thereof, for purposes of guiding the thread.

FIG. 3 illustrates how the thread upon leaving the thread calming and guiding element deviates to a minor extent from a straight line extending between the feeding element 2, the pair of delivery rollers 3 and 3' and the element 8. However, the angle .alpha. formed with the just mentioned straight line should be approximately zero in the top position of the balloon thread guide 7. The purpose of this arrangement consists in that during the entire period in which thread is wound onto the thread carrier the thread is in frictional contact with the thread calming and guiding element 8. For purposes of impeding the transmission of the twist as little as possible and for purposes of preventing braking of the thread, the friction is kept as small as possible.

In accordance with a further feature of the present invention, the thread calming and guiding device is arranged in such a way that the point of junction can be displaced from its central position between the fiber bands and that different fiber band lengths can be obtained. To this end, the thread calming and guiding device is provided with a so-called "changing" device (Changiervorrichtung) known in the art. The "changing" speed can be uniform or can vary during one stroke or several strokes, or the stroke can remain uniform or can vary continuously. The calming and guiding device is provided with several recesses for guiding the band or bands. By placing the thread into a certain recess, a displaced stroke of the "changing" can be achieved. Moreover, different thread effects and thread qualities can be achieved without "changing" by placing the thread into a certain recess of the thread calming and guiding element.

FIGS. 4 and 5 diagrammatically illustrate these further modifications of the method according to the present invention. The point of junction 5 is not centrally located between the fiber bands 1 but displaced to one side, and the bands have different lengths. In FIG. 4 the extreme positions of the thread calming and guiding element during one stroke of the "changing" is shown. For purposes of obtaining different thread effects and qualities, the "changing" speed as well as the stroke of the "changing" can be varied.

FIG. 5 shows a method similar to FIG. 4 with a thread-guiding element of cylindrical shape and with three recesses 12. The distance between the recesses 12 as a rule corresponds to half the distance between the fiber bands. The dash lines shown in FIG. 5 illustrate the course of the thread when the same is placed in one or the other of the outer recesses 12 of the element 8.

Further variations in the production of a thread or yarn are possible, if the thread guiding and calming element 8, as shown in FIG. 6 is provided with several recesses 12 which are spaced from each other a distance which is smaller than half the distance between the fiber bands.

The thread calming and guiding elements with several recesses 12 may be arranged stationarily or may be movable as indicated by arrow A. If, by means not shown in the drawing, the thread is during one or several strokes of the "changing" device placed into a different one of the recesses 12, different thread effects and qualities can be achieved.

FIGS. 7 and 8 illustrate the thread-feeding element in greater detail. The fiber bands 1 are fed through guiding eyelets 9, the spacing between which can be adjusted by slots 11 and by screws or similar elements 10.

While preferred embodiments of the method and apparatus according to the present invention have been described above, it is to be understood that the invention is not limited thereto, but comprises any modifications within the scope of the appended claims.

Claims

What we claim is:

1. A method of spinning, doubling and twisting fiber bands in an apparatus comprising a drafting device with a pair of delivery rollers, and a twisting member, which comprises the steps of: discharging the fiber bands separately and at a given distance from each other from said pair of delivery rollers, combining said fiber bands into a thread between the drafting device and the twisting member at a free-floating point the location of which is determined by the amount of twist imparted upon said thread in said twisting member, the distance of said fiber bands from each other, the number of fibers in the fiber bands, the size and resistance to twisting of the thread, and establishing a free path for said fiber bands between said point and said pair of delivery rollers to permit therebetween unimpeded transmission of the imparted twist.

2. A method according to claim 1, comprising the step of guiding and calming said thread at a point between first-mentioned point and said twisting member.

3. A method according to claim 1, wherein said fiber bands are combined into a thread at a point centrally between said fiber bands such that the length of each fiber band between said pair of delivery rollers and said point is the same.

4. A method according to claim 1, wherein said fiber bands are combined into a thread at said point noncentrally between said fiber bands such that the length of the fiber bands between said pair of delivery rollers and said point varies.

5. An apparatus for spinning, doubling and twisting fiber bands, comprising: a drafting device including a pair of delivery rollers for discharging the fiber bands therefrom, a twisting member for imparting twist on a thread combined from said fiber bands at a point between said pair of delivery rollers and said twisting member, and a thread guiding and calming device between said point and said twisting member.

6. An apparatus according to claim 5, wherein said thread guiding and calming device is provided with recess means for receiving the thread and is movable transversely to said thread.

7. An apparatus according to claim 6, wherein said thread guiding and calming device is arranged centrally with respect to the fiber bands discharged from said pair of delivery rollers.

8. An apparatus according to claim 6, wherein said thread guiding and calming device is arranged so that the angle formed between the thread passing therefrom to said twisting member and a straight line extending between the point of discharge of said fiber bands from said pair of delivery rollers and to said recess and beyond is approximately zero degrees.

9. An apparatus according to claim 5, which comprises thread-guiding means arranged in front of said drafting device for spacing the fiber bands from each other, said guiding means being provided with means for adjusting the spacing between the fiber bands.

10. An apparatus according to claim 6, wherein said recess means includes a plurality of recesses, and means for moving said thread guiding and calming device transversely to said thread selectively with a uniform stroke and speed.

11. An apparatus according to claim 6, wherein said recess means includes a plurality of recesses, and means for moving said thread guiding and calming device transversely to said thread discontinuously selectively with varying stroke and speed.