GB2164671A

GB2164671A - Fibre individualizing device of an open-end spinning unit

Info

Publication number: GB2164671A
Application number: GB08521780A
Authority: GB
Inventors: Frantisek Ferkl; Oldrich Tesar; Milos Vecera; Josef Skala; Miloslav Jiskra
Original assignee: Vyzkumny Ustav Bavlnarsky AS
Current assignee: Vyzkumny Ustav Bavlnarsky AS
Priority date: 1984-09-19
Filing date: 1985-09-02
Publication date: 1986-03-26
Also published as: IT8522077A0; CS249280B1; IT1185893B; GB8521780D0; CH669403A5; GB2164671B; DE3533470A1; DE3533470C2

Abstract

An apparatus enables fibres to be stripped in a simple and perfect way off a wide opening cylinder 12 and to be fed under optimal pneumatic conditions and in straight state into a fibre supply duct 21 and finally supplied to the spinning rotor 4. To meet this object, the first side wall (25) of said duct 21 is aligned with the first side wall (13) of the cylindrical cavity 11 accommodating the cylinder 12 while the second side wall (26) is spaced from the first side wall 25 at distance which is smaller than half of the cylinder 12 width and merges from a separating edge (23) in the fibre stripping zone A into a directing stripping wall (32) which is oriented obliquely to the second side wall (14) of said cavity 11 and perpendicular to the axis of the cylinder 12. The inner edge 33 of said wall (32) corresponds to the cylindrical wall 24 of said cavity 11 and forms together with said edge (23) a separating knife extending along the entire operating width of the cylinder 12. <IMAGE>

Description

SPECIFICATION Fibre individualizing device of an open-end spinning unit The invention relates to a fibre individualizing device of an open-end spinning unit, comprising in its housing a fibre opening cylinder accommodated in a cylindrical cavity masked from either side by parallel side walls, said cavity communicating with a fibre supply duct having an outlet opening and defined, on the one hand, by converging side walls, and, on the other hand, by an inner wall meeting at a separating edge, the cylindrical wall of said cavity and by an outer wall merging in a fibre stripping zone into a planar wall opposite the opening cylinder, said planar wall communicating with an air inlet.

There are known apparatuses for continuously spinning yarn from individualized fibres in openend spinning machines, wherein the fibre supply duct opens by its outlet opening under a separating disc extending into the spinning rotor. The disc is provided about its overall periphery, or at least a part thereof, with a groove for guiding fibres to the collecting groove of the rotor and simultaneously for protecting yarn being build infront of said fibres which are fed into the groove always into the groove always in one and the same point (Czechoslovak Inventor's Certificate No. 125.190).

The fibre supply duct is provided either immediately in the housing of the fibre individualizing device, or in a specific insert, and its cross-section decreases from the fibre opening cylinder to the spinning rotor.

The development of the open-end rotor spinning process is accompanied by steadily raising the revolution rate of the spinning rotor which necessarily brings about the reduction of dimensions of associated elements such as the above-mentioned disc, the so-called separator in which an outlet aperture for individualized fibres is provided. As well the space below the separator should be modified.

A problem encountered with high-speed spin ning rotors operating at more than 50,000 r.p.m.

and having, for the reasons of strength, their diam eter reduced up to e.g. 30mm, consists in that such rotors have to be supplied with larger amounts of fibres, which means that the individualizing de vices have accordingly to be dimensioned for a larger fibre delivery. Since, for technological rea sons, the revolution rates of the fibre opening cyl inders cannot be further raised, it is their width that must be enlarged. It is admitted that some embodiments based upon the installation of more than one opening cylinder e.g. two, have solved this problem but such systems are too expensive.

The West-German Publ. Appln. no. 2,177,948 dis closes a spinning unit having a wide fibre opening cylinder. One of the side walls of the fibre supply duct is aligned with the front wall of the cavity ac commodating said opening cylinder or, optionally, with the side wall of the air conduit up to the air inlet hole thereof while the other side wall of the supply duct converges to its outlet opening and its tapered. The separating edge extends across the entire width of the opening cylinder and is oblique so as to accommodate the fibre supply to the form of this outlet opening.

A disadvantage of this arrangement is an abrupt tapering of the fibre supply duct in view of its length, or, in other words, in a relatively great difference in cross-section of the duct between its large inlet at the separating edge and its small outlet opening. Consequently, there is produced in the supply duct an air pressure which rather impairs than supports the process of stripping fibres off the opening cylinder clothing. Thus the fibres are not conveyed continuously into the supply duct and are not acted upon by an accelerated air flow so as to straighten them while being stripped as described in the above-mentioned Czechoslovak Inventor's Certificate No. 125,190 wherein the width of the supply duct corresponds to that of the opening cylinder. Thus the fibres get crimped or, due to inappropriate air pressure conditions, they even fail to be conveyed into the supply duct.The fibres revolve in the cylinder clothing up to the sliver feeding region where they negatively influence the continuing process of individualizing fibres from the fibrous sliver.

It is an object of the present invention to provide a fibre individualizing device with a wide fibre opening cylinder, ensuring, in relatively simple way, the perfect conveyance of fibres from said cylinder to the fibre supply duct under optimum pneumatic conditions therefor, and the transport of straightened fibres into the spinning rotor.

According to the invention there is provided a fibre individualizing device of an open-end spinning unit, comprising in its housing a fibre opening cylinder accommodated in a cylindrical cavity masked from either side by parallel side walls, said cavity communicating with a fibre supply duct having an outlet opening and defined, on the other hand, by converging side walls, and, on the other hand, by an inner wall meeting at a separating edge, the cylindrical wall of said cavity and by an outer wall merging in a fibre stripping zone into a planar wall opposite the opening cylinder, said planar wall communicating with an air inlet, a first side wall of the fibre supply duct being aligned with a first side wall of the cylindrical cavity, the second side wall of the fibre supply duct being spaced from said first side wall at a distance which is smaller than a half of the width of the fibre opening cylinder, and merging from said separat ing edge in a fibre stripping zone into a directing stripping wall which is inclined to the second side wall of the cylindrical cavity and stands perpendic ular to the axis of the opening cylinder, the inner edge of said directing stripping wall corresponding to the cylindrical wall of said cavity and forming together with said separating edge a separating knife extending along the entire operating width of the opening cylinder, said knife being designed for stripping the individualized fibres from said cylin der.

An advantage of the fibre supply duct and the fibre stripping zone with the directing stripping wall and the inner edge in the form of the so-called separating knife consists in that no energetic losses in the air flow occur and that the required technological is achieved, viz. the stripping of fibres within the entire width of the fibre opening cylinder as well as the conveyance thereof into the tapering supply duct. The directing stripping wall is disposed in a part of opening cylinder width across the flow of stripped fibres, and forms in front of itself an air curtain which aids the process of stripping fibres and the conveyance thereof to a lateral portion in which the supply duct is provided, the fibres not being braked by said curtain at said directing stripping wall.Since the lower edge of the directing stripping wall corresponds to the cylindrical wall of the cavity accommodating the fibre opening cylinder, the fibres are stripped in that part of the opening cylinder width in which said directing stripping wall is disposed, predominantly by centrifugal force, which means by a minor effect of air which flows particularly in that part of the opening cylinder which is orientated toward the fibre supply duct. In this way there are provided positive pneumatic conditions for the fibre transport in the supply duct while the fibres conveyed by the directing stripping wall from the opening cylinder width only condense the fibre flow in said duct without substantially impairing the air flow.

A preferred embodiment of the present invention will hereinafter by described by way of example with reference to the accompanying schematic drawings, wherein: Figure 1 is a sectional view of a spinning unit comprising the spinning device and the fibre individualizing device; Figure 2 is a detail sectional top view of the fibre supplying duct and the fibre stripping zone, taken along the line il-ll in Figure 1; Figure 3 is an enlarged sectional side view of the profile of fibre supply duct, taken along the line Ill- Ill in Figure 2; and Figure 4 is a perspective view of the transition area between the fibre stripping zone and the fibre supply duct.

When turning to the drawings, and particularly to Figure 1 thereof, it can be seen that the openend spinning unit comprises a spinning device 1 and a fibre individualizing device 2 which are adapted to be tilted from each other. The spinning device 1 accommodates in its housing 3 a spinning rotor 4 which is provided with ventilating holes 5, a sliding wall 6 and a collecting groove, 7. The spinning rotor 4 is driven by means of a belt 8 and a pulley 9. The fibre individualizing device 2 consists of another housing 10 accommodating in its cylindrical cavity 11 a fibre opening cylinder 12.

The cavity 11 is covered from its sides by parallel side walls 13, 14 (Figures 2 and 4) and communicates with a recess 16 in which a feed roller 15 and a thrust shoe 17 are arranged, which provide a nip for a fibrous sliver 18 supplied. In the housing 10 of the fibre individualizing device 2 there is further provided an impurity ejecting opening 19 communicating with a following system of impurity withdrawing conduits 20.

The cylindrical cavity 11 merges further into a fibre supply duct 21 for supplying discrete fibres into the spinning rotor 4. The supply duct 21 is defined, on the one hand, by an inner wall 22 which meets at a separating edge 23, the cylindrical wall 24 of the cavity 11, and, on the other hand, by side walls 25, 26 and an outer wall 27. The duct 21 is ended by an outlet opening 28. The outer wall 27 of the fibre supply duct 21 merges into a planar wall 29 toward the so-called fibre stripping zone A (Figure 3) of the fibre opening cylinder 12, said zone A being defined, adjacent the duct 21, by said separating edge 23, and, adjacent an air inlet 30, by an end edge 31. The planar wall 29 which is disposed opposite the separating cylinder 12, merges into said air inlet 30 supplying said fibre stripping zone A with air.The above-described embodiment is known e.g. from the West-German Publn. No. 2,177,948 (see above). The following description specifies a new, inventive embodiment of the fibre supply duct 21 and the transition area between the later and the fibre stripping zone A.

Figure 2 shows a top view of the fibre supply duct 21 and the fibre stripping zone A, wherein the lefthand side wall 25 of the duct 21 is aligned with the left hand side wall 13 of the cylindrical cavity 11. The second side wall 26 extends from the outlet opening 28 to the separating edge 23 at an angle alpha varying, preferably, in the range of from 5 to 25". However, the substantial feature is in that the second side wall 26 is in the lefthand half width of the fibre opening cylinder 12, which means in the same half in which the first side wall 25 is provided. Thus the distance between the two walls 25, 26 is within the entire cross-section smaller that is the half width S of the fibre opening cylinder 12.This distance may correspond, in the region of the separating edge 23, to about one third of the opening cylinder 12 whereupon it diminishes toward the outlet opening 28. The second side wail 26 of the fibre supply duct 21 then merges substantially from the separating edge 23 1 or slightly upstream thereof, i.e. in the stripping zone A I into a directing stripping wail 32 which is inclined to the second front wall 14 of the cylindri cal cavity 11, which means across the remaining half width of the fibre opening cylinder 12, viz.

across the flow of stripped fibres.

The directing stripping wall 32 is perpendicular to the axis of the fibre cylinder 12, or to the outer wall 27 of the fibre supply duct 21, or to the planar wall 29 opposite the cylinder 12 in the fibre stripping zone A. The inner edge 33 of said directing stripping wall 32 corresponds to the cylindrical wall 24 of the cavity 11, which means that the distance between said inner edge 33 and the fibre opening cylinder 12 is the same as the distance between the cylinder 12 and the remaining cylindrical wall 24. The important feature is in that said edge 33 forms together with the separating edge 23 the so-called separating knife extending within the entire width of the fibre opening cylinder 12, and designed for stripping the individualized fibres.The directing stripping wall 32 is inclined from the sep arating edge 23 of the fibre supply duct 21 relative to the first side wall 13 of the cylindrical cavity 11 at an angle beta of from 30 to 55 . However, the directing stripping wall 32 is to extend preferably toward the second front wall 14 of the cavity 11 into the region of the smallest distance L between the fibre opening cylinder 12 and the opposite planar wall 29 whereby it is ensured that the fibres stripped by centrifugal force in the stripping zone A enter the supply duct 21. The directing stripping wall 32 can be either planar, or slightly concave.It can merge into the second side wall 26 immediately at the separating edge 23, or said second side wall 26 can be slightly extended into the fibre stripping zone A and then, after being deflected at 34, it merges into said directing stripping wall 32.

In operation, the sliver 18 of fibrous material is supplied by the feed roller 15 to the opening cylinder 12 which separates fibres therefrom and carries them in its toothed clothing, or between said clothing and the cylindrical wall 24 of the cavity 11, toward the stripping zone A. The latter is additionally supplied with air through the air inlet 30, due to a sub-atmospheric pressure produced by the ventilating holes 5 in the spinning rotor 4. In the stripping zone A, fibres are stripped off the toothed clothing of the opening cylinder 12 and are conveyed into the supply duct 21 and finally into the spinning rotor 4. The fibres are stripped off the opening cylinder 12, on the other hand, by centrifugal force, and, on the other hand, by air flowing from the inlet 30 directly into the supply duct 21.

As can be seen in Figure 2, the stripping takes place in that part of width of the opening cylinder 12 which is of the same width as the inlet into said duct 21 in the region of the separating edge 23. In the other portion of width S of the opening cylinder 12, where the fibre flow is baffled by the directing stripping wall 32, the fibres are stripped predominantly by the centrifugal force and introduced into the air flow by which they are carried along said wall 32 into the supply duct 21. Upstream of the directing stripping wall 32 there is produced an uplift air pressure which is transferred, without friction at said wall 32, into said supply duct 21, as indicated by lines of flow in Figure 2. The above described arrangement of the transition between the fibre stripping zone A and the fibre supply duct 21 as well as the actual embodiment thereof relative to the width of the fibre opening cylinder 12 prevent the fibres from revolving in the clothing of the opening cylinder 12, and provide an optimum parallelisation of fibres and the transport thereof in this condition to the supply duct 21 and therethrough into the spinning rotor 4, whereby first-grade yarn quality is obtained.

The configuration shown in Figure 2 may be modified to the opposite hand relative to the medial plane of the cylindrical cavity 11.

Claims

1. A fibre individualizing device of an open-end spinning unit, comprising in its housing a fibre opening cylinder accommodated in a cylindrical cavity masked from either side by parallel side walls, said cavity communicating with a fibre supply duct having an outlet opening and defined, on the one hand, by converging side walla, and, on the other hand, by an inner wall meeting at a separating edge, the cylindrical wall of said cavity and by an outer wall merging in a fibre stripping zone into a planar wall opposite the opening cylinder, said planar wall communicating with an air inlet, a first side wall of the fibre supply duct being aligned with a first side wall of the cylindrical cavity, the second side wall of the fibre supply duct being spaced from said first side wall at a distance which is smaller than a half of the width of the fibre opening cylinder, and merging from said separating edge in a fibre stripping zone into a directing stripping wall which is inclined to the second side wall of the cylindrical cavity and stands perpendicular to the axis of the opening cylinder, the inner edge of said directing stripping wall corresponding to the cylindrical wall of said cavity and forming together with said separating edge a separating knife extending along the entire operating width of the opening cylinder, said knife being designed for stripping the individual fibres from said cylinder.

2. A fibre individualizing device as claimed in claim 1, wherein the directing stripping wall is inclined from the separating edge of the fibre supply duct to the first side wall of the cylindrical cavity at an angle of from 30 to 55 .

3. A fibre individualizing device as claimed in claim 1 or 2, wherein the directing stripping wall is oriented in the fibre stripping zone from the separating edge of the supply duct to the second side wall of the cylindrical cavity into the region of the smallest distance between the planar wall and the opening cylinder.

4. A fibre individualizing device as claimed in any one of claims 1, 2 and 3, wherein the second side wall of the supply duct includes an angle of from 5 to 25 with the first side wall thereof.

5. A fibre individualizing of an open-end spinning unit, substantially as hereinbefore described with reference to the accompanying drawings.