The invention relates to an open-end rotor spinning device comprising a one-sidedly open spinning rotor, a positively driven guide body in the form of a ring, tube, or the like, which enters by its rear end coaxially the spinning rotor and whose inner wall serves for depositing supplied fibres, for supportingly guiding and finally delivering them to the spinning rotor, further an immovable covering body which is associated with the front end of the guide body and through which a guide tube or duct extends for supplying fibres to the inner wall of said guide body, and a take-off duct or tube which extends through the axis of the spinning rotor or that of the covering body and which serves for withdrawing yarn out of the spinning rotor, there being provided between the spinning rotor and the guide body an annular spacing through which the communicating spaces of the spinning rotor and the guide body are connected to a first sucking unit.
In a known device of the above-described kind an properties disclosed in DE-A 2,126,841 separated fibres are supplied to the inner wall of the guide body by means of air flowing through the guide duct into the communicating spaces of the spinning rotor and the guide body and therefrom out through the annular spacing between the spinning rotor and the guide body. Since the guide body rotates, the fibres advance, due to the action centrifugal forces, on the inner wall of said body toward the spinning rotor which rotates in the same or the opposite direction as the guide body. Finally, the fibres get on to the wall of the spinning rotor and are entrained into its interior where they are deposited, taken on the end of yarn being built, and withdrawn therefrom in yarn form. As being entrained into the spinning rotor, the fibres are temporarily supported by the inner wall of the guide body so that they are straightened whereby the quality of final yarn product is positively influenced.
A disadvantage of the above device resides in that it does not allow a wide assortment of yarns from cotton fibres and synthetic cotton-type fibres to be manufactured; actually, there are concerned only the so called carded yarn sorts 14.5 to 100, or 166 tex count for the manufacture of which relatively short and coarse fibres are used. Admittedly, if using finer fibres it is possible to approach even the count range of the so called combed yarn sorts but the final product does not reach the desired quality. It is why such combed yarns of from 5 to 14.5 tex are manufactured exclusively in ring spinning frames from relatively long and fine fibres. Such a process, however, has to be preceded by relatively complicated and expensive preparatory steps; the carding step is usually followed by quadruple draft on three drawing frames and by doubling on a silver doubler, or, alternative, a shortened method of double draft is availed of, and particularly on one drawing frame, followed by silver doubling. The thus arising lap is then supplied to a combing machine whereupon it is subjected to double to triple drafting step - Waste ejected from the combing machine - the so called noils - are ordinarily used for manufacturing vigogne yarns.
It is an object of the present invention to take such measures with the device of the above-described type and properties that make it possible, on the one hand, to manufacture first-grade yarns of combed character from fibres suitable for spinning combed yarns without preceding combing step followed by drafting, or, on the other hand, yarns of combed character at least within the count range of combed yarns, including also coarser combed yarns, from fine fibres suitable for spinning carded yarns.
To meet this object, there is provided at the side of front end of the guide body an air discharge hole through which the communicating spaces of the spinning rotor and the guide body are connected either to a second sucking unit, there being arranged at least in front of the first sucking unit an air regulating member or at least the first sucking unit having a selectable sucking output, or also to said first sucking unit but in parallel to the annular spacing between the spinning rotor and the guide body, the air regulating members being associated with said annular spacing and the air discharge hole. These measures, namely, enable the air flow values or rates in the device to be adjusted in such a way that almost all the air volume serving for supplying the fibres, leaves the inner spaces of the spinning rotor and the guide body through the air discharge hole at the side of front end of the guide body, while only a small air portion escapes through the annular spacing between the spinning rotor and the guide body. By means of air escaping from said communicating inner spaces of the spinning rotor and the guide body through the annular space between said two elements, short fibres of selectable length are then ejected outside the spinning rotor while the remaining, longer fibres are spun in the spinning rotor to yarn of the desired kind and quality, viz. yarn of combed character. The process of withdrawing short fibres of exactly predetermined length and of leaving longer fibres of desired length in the spinning process can be effected by adjusting the revolution rates of the spinning rotor and the guide body in a ratio. It is to be noted that the ejected short fibres do not practically mean any production loss, since they can be used for further processing as, for instance, to yarns of another sort.
It, however, is also possible to adjust the afore-mentioned ratio between the revolution rates of the spinning rotor and the guide body as well as the air flow rate in the annular spacing between said two elements in such a manner that any portion of fibres supplied to the spinning rotor is not withdrawn or ejected. This means that the device can operate as the conventional open-end spinning machine and that it is capable of producing a wider yarn assortment. Apart from this, the fact that almost all air volume leaves the communicating spaces of the spinning rotor and the guide body at the side of front end of the guide body, is also advantageous in that the air flows from the guide duct to the air discharge hole on a short path so that it cannot influence in any way the advance of fibres toward the spinning rotor and the process of fibre depositing in its interior.
Actually, the air discharge hole can be made as a through hole which is provided in the covering body and whose inlet portion at the inner side of said covering body has the form of at least a part of annular cavity and extends in peripheral direction along the inner marginal portion of said guide body, or as an annular gap between the guide body and the covering body. If the air discharge hole is through hole as hereinabove set forth, a labyrinth packing should preferably be provided between the front end of the guide body and the covering body, the packing serving for perfectly separating the inlet portion of said through hole from the ambient atmosphere so that no air losses occur.
For every case, however, it is advisable according to the invention, when a filtering element for retaining and collecting fibres is associated with the annular spacing between the spinning rotor and the guide body.
Some preferred embodiments of the open-end rotor spinning device according to the present invention will hereinafter be described with reference to the accompanying schematic drawings in which
The spinning station or unit forming one consituent of the device according to the invention can be - except for some modifications due to the new system of sucking air off the communicating spaces of the spinning rotor and the guide body - of a usual construction. In the same way it is possible to assemble a conventional open-end rotor spinning machine from a plurality of such units and an air sucking system therefor, the system comprising either a first and a second air sucking system, or the first sucking system only.
As can be seen in the drawings, and particularly Figure 1 thereof, the spinning rotor 2 of the spinning unit 1 is fixed onto a driven shaft 3 which is mounted for rotation in a bearing bush 4 received for reciprocation in a bushing portion 5 of a rotor box 6 and secured therein by a fastening bolt 7.
The spinning rotor 2 has the form of a shallow dish with a flat circular bottom 8, a rounded mouth 9 of a smaller diameter than said bottom 8, and an inner wall 10 outstanding from the bottom 8 and conically tapering toward the mouth 9. The bottom 8 and the wall 10 form together a fibre collecting channel.
The rotor box 6 surrounding, at a radial distance, the spinning rotor 2 is provided at its front, also open side with a recess 11 coaxial to the spinning rotor 2, in which a rotary, positively driven guide body 13 is received and mounted by means of an antifriction radial bearing 12. The guide body 13 has the form of an annulus and is provided, at its rear end 14 facing the spinning rotor 2, with a frontal circular recess 15 by which said rear end 14 is radially divided into an inner and an outer portion 16 and 17, respectively; the inner portion 16 is disposed in the mouth 9 of the spinning rotor 2 while the outer portion 17 outside said mouth. Since, however, the spinning rotor 2 is somewhat spaced apart from the guide body 13 in axial direction, there arises between the mouth 9 of the spinning rotor 2 and said portions 16, 17 of the rear end 14 of the guide body 13, including the transition between said portions, an annular spacing 18 which connects the communicating spaces of the spinning rotor 2 and the guide body 13 together with an inner air space 19 of the rotor box 6. This inner air space 19 is confined, at the side of the rotor box 6, by its rear wall 20, an annular projection 21 provided in a radial plane with said outer portion 17 of the rear end 14 of the guide body 13 as a sealing partition, and by an inner peripheral wall 22 between said rear wall 20 and said annular projection 21, and communicates via hole 23 with a first sucking pipeline 24.
The inner wall 25 of the guide body 13 has the form of the lateral area of a cone, its minimum diameter being at the side of front end 26 of the guide body 13.
The rotor box 6 is covered by a removable but otherwise immovable covering body 27 the inner wall 28 of which is spaced apart at a very small distance from the front end 26 of the guide body 13.
As it is shown in Figure 1, the device is provided with an air discharge hole constituted by a through hole 29 leading in radial direction to an extended axis X of revolution of the guide body 13 through the body 27, and connected to a second sucking pipeline 30. The inlet portion 31 of said pipeline 30 has the form of an annular cavity and extends in peripheral direction along an inner marginal portion 32 of the guide body 13 as it is apparent from Figure 2. In some cases, however, the through hole 29 can be provided in a tubular member inserted into the covering body 27. Such an embodiment is not shown in the drawings.
Another embodiment of the air discharge hole is shown in Figure 3. It consists of an annular gap 33 between the inner marginal portion 32 of the guide body 13 and a peripheral surface 34 of the conical projection 35 provided on the inner wall 28 of said covering body 27, the projection being disposed in the front end 26 of the guide body 13. Also in this embodiment there is provided in the covering body 27 the same through hole 29 as shown in Figure 1. The inlet portion 31 of said hole 29, however, has the form of a complete annular cavity and is an immediate proximity of said conical projection 35.
Owing to the provision of through holes 29 in both of the afore-described embodiments there is installed between the front end 26 of the guide body 13 and the covering body 27 a labyrinth packing 36 consisting, as shown in Figure 1, of an annular projection 37 provided on the inner wall 28 of the covering body 27 and of a corresponding recess 38 on the facing front surface of the front end 26 of the guide body 13. It, however, is to be understood that the packing elements can be arranged in a reversed, or any other alternative embodiment, provided they exhibit a desired, air penetration preventing effect.
As can be seen in Figure 1, a guide tube 40 for supplying fibres 39 to the inner wall 25 of the guide body 13 extends through the covering body 27; alternatively, if the conical projection 35 is provided on the inner wall 28 of said body 27 - as hereinabove set forth - the guide tube 40 can be replaced by a guide duct 41 (Fig. 3). In every case, however, also a take-off tube 42 extends through the covering body 27, through which yarn 43 is withdrawn out of the spinning rotor 2.
The air sucking system as shown in Figure 1 is a central system for a plurality of spinning stations 1; it comprises a first main conduit 44 which is connected to a first sucking unit 45 with an upstream filtering element 46 and into which enters the first sucking pipeline 24 leading from the individual spinning stations 1. A second main conduit 47 is connected to a second sucking unit 48 into which the second sucking pipeline 30 opens; the latter leads also from the individual spinning stations 1. The two sucking units 45, 48 and the filtering element 46 can be of any structure which is usual for textile machines with air sucking regimes. In front of the two sucking units 45, 48 there are arranged air regulating members 49, 50, respectively, e.g. in the form of a valve which, however, can be omitted if installing sucking units 45, 48 with selectable sucking output.
Figure 4 shows also an alternative central air sucking system comprising the first main conduit 44 and the second main conduit 47 which are connected together at their homothetic ends to form a central duct 51 which is then connected to the first sucking unit 45 with upstream filtering element 46. Also the first sucking pipeline 24 enters the first main conduit 44, and the second sucking pipeline 30 the second main conduit 47. The air regulating members 49 and 50 are associated with the annular spacing 18 between the spinning rotor 2 and the guide body 13, and with the through hole 29 in the covering body 27, and are disposed at the ends of said first main conduit 44 and the second main conduit 47, respectively. In this case, the filtering element 46 can alternatively be installed in the first main conduit 44 in front of the respective air regulating member 50 as indicated in Fig.4 by dash contours.
Irrespective of the embodiment of the air discharge hole as shown in Figures 1, or 2, and of the air sucking system according to Figures 1, or 4, the process of manufacturing yarns of combed character in the device of the invention takes place as follows:
Depending on the adjustment of operation parameters, including the size of annular spacing 18 between the spinning rotor 2 and the guide body 13, the two latter elements rotate in the same direction; however, the guide body 13 rotates slower than the spinning rotor but, on the other hand, faster than is the velocity of air supplying fibres 39 to the inner wall 25 of said body 13. Simultaneously, almost all of the volume of fibre carrying air which enters the communicating inner spaces of the spinning rotor 2 and the guide body 13 leaves said spaces at the side of front end 26 of said body 13 whereas only a small, remaining air portion escapes through the annular spacing 18 between the spinning rotor and the guide body.
Fibres 39 are supplied, under assistance of air flow, from a fibre opening device (not shown) in which they are separated from a fibrous sliver, and particularly a carded, or drafted sliver. After engaging the inner wall 25 of the guide body 13, the fibres 39 are caused, by the action of centrifugal forces, to advance on this inner wall 25 toward the spinning rotor. Before, however, reaching the wall 10 of the spinning rotor 2, they have first to overcome the annular spacing 18 between the spinning rotor 2 and the guide body 13. So the fibres 39 are exposed to the action of air flow escaping through said annular spacing 18 whereby the fibres 39 leaving the inner wall 25 of the guide body 13, change abruptly their course to a peripheral one as indicated, for better understanding, in Figures 5 and 7 by angles A and B. Thus their trajectory S between the inner wall 25 if the guide body 13 and the wall 10 of the spinning rotor 2 has a section U (Fig. 6) in which fibres the length of which is smaller than that of said section, may get airborne, which means that no one of their portions comes into contact either with the inner wall 25 of the guide body 13, or with the wall 10 of the spinning rotor 2.
Such fibres 39 (hereinafter referred to as "short fibres 52") are then easily entrained by air escaping through the annular spacing 18 between the spinning rotor 2 and the guide body 13 and withdrawn outside the spinning rotor 2 whereas the remaining longer fibres 53 follow undisturbed their way to said spinning rotor 2. Accordingly, it is made possible, within every predetermined ratio between revolutions rates of the spinning rotor 2 and the guide body 13, to withdraw or eject short fibres 52 of a quite definite length and to leave the longer fibres 53 in the spinning process to be processed to yarn of a desired kind and quality. It is to be noted that the process of entraining and withdrawing short fibres 52 does not lay extreme claims on power; it, however, has been ascertained that it is sufficient when the speed of air flow escaping through the annular spacing 18 between the spinning rotor 2 and the guide body 13 does not exceed 30 metres per second. On the contrary, higher speed lead not only to power losses but also, especially, to the ejection of short fibres 52 having a greater length than it is desired. Actual values of these air velocities are usually adjusted empirically by means of air sucking regulation.
Apart from the above described manner, the exact length of fibres 52 to be ejected can also be controlled by adjusting the size of annular spacing 18 between the spinning rotor 2 and the guide body 13. After loosening the bolt 7 securing the bearing bush 4 for the shaft 3 of the spinning rotor 2, both the rotor and the bush can be axially displaced into desired positions wherein the bearing bush 4 can be fastened again by said bolt 7. It, however, has been found out that the size of said annular spacing 18 can be, in many cases, adjusted once for ever.
In order that the process of withdrawing short fibres 52 be better understood, Figure 5 shows successive positions of one and the same short fibre 52. As can be seen, a short fibre 52 takes on its trajectory S a first position P1 on the inner wall 25 of said guide body 13, then a second position P2 in the section U between the inner wall 25 of the guide body 13 and the wall 10 of the spinning rotor 2, a third position P3 in the annular spacing 18 between the spinning rotor 2 and the guide body 13, and a fourth position P4 in the inner air space 19 of the rotor box 6. The corresponding positions P1, P2 and P3 of the short fibre 52 are shown in Figure 6.
Longer fibres 53 (Fig. 7) are not withdrawn, since, as ascertained, they are always on their trajectory S in contact with the inner wall 25 of the guide body 13, or with both said inner wall 25 and the wall 10 of the spinning rotor 2, or with said positions of one and the same longer fibres 53 are indicated in Figure 7 by symbols P11, P12 and P13.
Thus from fibres 39 supplied to the spinning rotor 2 there are separated and ejected short fibres 52 of length corresponding to the predetermined revolution rates of the spinning rotor 2 and th guide body 13 as well as to the flow welocity of air escaping through the annular spacing 18 between the spinning rotor 2 and the guide body 13 whereas the longer fibres 53 are subsequently straightened and conveyed, as being exposed to centrifugal forces and to the supporting action of the wall 10 of the spinning rotor 2, to the collecting channel formed by the bottom 8 and the wall 10 of the spinning rotor 2, wherein they are deposited and wherefrom they are continuously taken on to the open end of yarn 43 and withdrawn.
If a sliver is to be processed, having a staple fibre diagram insuitable for the orthodox combing step, which means, most frequently, that it contains a relatively great portion of short fibres 52, such raw material can be very effectively classified in the annular space 18 by separating short fibres 52 from it while the remaining, longer fibres 53 are processed to fine yarn 43. Such a material, however, does not contain such a portion of sufficiently fine fibres 39 enabling a very fine yarn 43 to be spun from the remaining longer fibres 53. In spite of this fact, it is possible to manufacture therefrom some yarn types still within the count range of fine combed yarns, i.e. up to 10 tex.
If, on the contrary, a sliver of fibres suitable for the ortho dox combing process is used, the annular spacing 18 between the spinning rotor 2 and the guide body 13 can be adjusted to cause short fibres 52 of e.g. 20 mm length to be ejected while the remaining, longer fibres 53 are then processed to a fine combed yarn 43
Both of the above described variants are very economical, since they substantially shorten the spinning process and enable also some low-grade fibrous materials to be used for the manufacture of fine yarns 43.
The ejected short fibres 52 accumulated in the filtering element can be then processed to another type of yarns, or fabrics. Since a very pure "waste" is concerned, the short fibres 52 can be returned to the carding machine, and after drafting them on a drawing frame, it is possible to process them to carded yarn sorts, and particularly in the conventional open-end rotor spinning machine, or in the device of the invention.