GB2167455A - Frictional open-end spinning apparatus - Google Patents

Abstract

The frictional open-end spinning apparatus comprises a rotary outer cylinder (14) with the inner frictional surface (15) of which a perforated frictional surface (16) of an inner cylinder (17) is associated. In the inner cylinder (17) which is mounted for opposite rotation than the outer one (14), a suction nozzle (32) is provided. It is an object of the invention to provide an optimum position of a fibre supply duct (11) relative to the axes of rotation of both the inner and the outer cylinder (17, 14). A perpendicular projection of the longitudinal axis of the transport portion (13) of said fibre supply duct (11) onto a first plane comprising the two said axes of rotation, includes an acute first angle with a line along which said first plane intersect a second plane which is perpendicular to said first plane and passes through one of said axes or rotation, the perpendicular projection of the longitudinal axis of the transport portion (13) of the fibre supply duct (11) onto the second plane includes an acute second angle with the first plane, and the first plane includes an acute third angle with a longer of two axes of symmetry of each of cross-sections of the transport portion (13) of the fibre supply duct (11), said axes being perpendicular to each other. <IMAGE>

Description

SPECIFICATION Frictional open-end spinning apparatus The invention relates to a frictional open-end spinning apparatus.

In British Patent Specification No. 2,023,196 there is disclosed such an apparatus comprising a rotary outer cylinder having an inner frictional surface, an inner cylinder having a perforated outer frictional surface are mounted for opposite rotation in said outer cylinder, said two frictional surfaces being in a contactless engagement with each other whereby a wedge-like gap at the place of their nearest approach is formed therebetween, a suction nozzle arranged in said inner cylinder and defining by its mouth a confined suction field on said perforated frictional surface in the region of said wedge-like gap, and a fibre supply duct entering said outer cylinder from the exterior and having an outlet portion which is oriented toward the inner frictional surface of said outer cylinder movable to said wedge-like gap.

As experimentally ascertained, the spinning process wherein individualized fibres are supplied through a supply duct onto the friction surface of the outer cylinder, is more advantageous than the process wherein fibres are supplied onto the outer perforated frictional surface of the inner cylinder as described in the British Patent Specification No.

1,559,101.

The spinning process wherein individualized fibres are supplied onto the inner frictional surface of the outer cylinder, makes it possible to spin yarn of a better structure at a lower power consumption that in the spinning process according to the British Patent Specification No. 1,599,101. In this process, however, it is necessary to meet the condition that the fibres taken over by the inner frictional surface of the outer cylinder be longitudinally oriented in the direction of generatrix of said cylinder, or in the direction only slightly different therefrom.

At the impact of fibres onto the frictional surface, some factors such as the speed of fibre supply, peripheral velocity of frictional surface of the outer cylinder, and the direction of fibre motion at the instant of impact, manifest themselves. While the speed of fibre supply and the peripheral velocity of frictional surface of the outer cylinder is predominantly influenced by the operation of twisting means, the direction of fibre motion is an independent factor. As experimentally found out, this factor is very important. However, it has not yet been sufficiently dealt with in prior art.

It is an object of the present invention to ensure by simple means that the fibres when impacting onto the inner frictional surface of the outer cylinder, be oriented substantially in the direction of the generatrix of said surface, which condition is indispensable for producing yarn of an advantageous structure.

According to the invention there is provided a frictional open-end spinning apparatus, comprising rotary outer cylinder having an inner frictional surface, an inner cylinder having a perforated outer frictional surface and mounted for opposite rotation in said outer cylinder, said two frictional surfaces being in a contactless proximity with each other whereby a wedge-like gap at the place of their nearest approach is formed therebetween, a suction nozzle arranged in said inner cylinder and defining by its mouth a confined suction field on said perforated frictional surface in the region of said wedge-like gap, and a fibre supply duct entering said outer cylinder from the exterior and having an outlet portion which is oriented toward the inner frictional surface of said outer cylinder movable to said wedge-like gap, wherein a first imaginary plane passes through the axis of rotation of the outer cylinder and the axis of rotation of the inner cylinder while a second imaginary plane passes through one of said axes of rotation of the two cylinders and is perpendicular to said first plane, wherein a perpendicular projection of the longitudinal axis of a transport portion of the fibre supply duct merging into a bevelled outlet portion of said duct, onto said first plane includes an acute first angle with a line along which the two planes intersect each other, wherein the perpendicular projection of the longitudinal axis of the transport portion of the fibre supply duct onto the second plane includes an acute second angle with the first plane, wherein each of cross-sections of the transport portion of the fibre supply duct has two axes of symmetry perpendicular to each other, and wherein the first plane includes an acute third angle with the longer of said axes.

Preferably, the acute first angle is within the range of from 5" to 35 , the acute second angle is less than 15 , and the acute third angle is less than 20 .

If the above-described geometrical parameters of position of the longitudinal axis of transport portion of the fibre supply duct, and particularly of the preferred ranges of angles relative to the axes of the outer and the inner cylinder, are maintained, the individualized fibres are deposited onto the inner frictional surface of the outer cylinder in an optimum position for enabling yarn of excellent strength and uniformity parameters to be produced.

Some preferred embodiments of the apparatus according to the invention will hereinafter be described, by way of example, with reference to the accompanying schematic drawings, in which: Fig. 1 shows a side view of the spinning unit, partly in sections; Fig. 2 is a sectional view taken along the plane Il-li in Fig. 1; Fig. 3 is a detailed view showing a projection of the longitudinal axis of transport portion of a fibre supply duct onto a first plane; Fig. 4 is a detailed view showing a projection of the longitudinal axis of transport portion of a fibre supply duct onto a second plane; Fig. 5 shows a cross-sectional view of the transport portion of the fibre supply duct relative to the first plane; and Fig. 6 is a cross-sectional view showing a variant of position of the longer axis of symmetry of transport portion of the fibre supply duct relative to the first plane.

As can be seen in the drawings, and particularly Figure 1 thereof, the spinning unit comprises a fibre individualizing device 1, a twisting device 2 and a yarn take-off device 3. The fibre individualizing device 1 received in a housing 4 attached to the spinning unit frame (not shown) consists of a feed roller5 mounted for rotation in the direction of arrow 6 and associated with a fibre opening cylinder 8 which is mounted for counter-directional rotation (arrow 7) in a recess 9 of the housing 4 and is provided with a card clothing 10.

The recess 9 merges into a fibre supply duct 11 having a shorter upstream portion 12 which opens into the ambient temperature, and a longer downstream portion 13.

The twisting device 2 comprises an outer cylinder 14 having an inner frictional surface 15 which is in a close but contactless proximity with a perforated outer frictional surface 16 of an inner cylinder 17 mounted in the outer cylinder 14. The outer cylinder 14 is mounted for rotation in the direction of arrow 20 on a system of backing rolls 18 arranged on the spinning unit frame and driven from (not shown) driving means. The inner cylinder 17 is mounted for opposite rotation in the direction of arrow 21 in (not shown) bearings provided on the spinning unit frame.

Due to the close engagement of the two cylinders 14 and 17, there arises at either side of their nearest approach two wedge-like gaps. The gap 22 thereof which is engaged by the inner frictional surface 15 moving in the direction of arrow 20 as the first, is designed for the yarn production (Fig. 2).

The interior of the outer cylinder 14 is defined by two stationary end walls 23,24 which are in the close but contactless engagement with fronts of said outer cylinder 14 designed for ensuring a sufficient pressure gradient in said interior relative to the ambient atmosphere. In the end wall 23 two holes are provided; the hole 25 for passing the downstream portion 13 of the fibre supply duct 11 into the interior ofthe outer cylinder 14, and the hole 26 for withd rawing yarn Ptherefrom. The opposite front wall 24 has an aperture 27 for passing the inner cylinder 17.

While in the preferred embodiment of the apparatus, the two holes 25,26 are provided in the end wall 23, it is also possible to provide each of them in the other end wall 24.

The downstream portion 13 of the fibre supply duct 11 comprises a transport portion 28 having a longitudinal axis 29, and an output portion 31. The cross-section of the portion 28 which is perpendicular to said longitudinal axis 29, can be an optical geometrical enclosed figure such as a rectangle 30 (Fig. 2). The output portion 31 (Fig. 3) is oriented by its bevelled end toward the inner frictional surface 15 of the outer cylinder 14. The longitudinal axis 29 of said transport portion 28 passes through (not shown) centres of gravity of all of the areas of geometrical figures in any optical cross-sections of the transport portion 28.

In the interior of the inner cylinder 17 there is arranged a stationary suction nozzle 32 communicating with a (not shown) source of subatmospheric pressure. A slot 34 extending in the wall of the suction nozzle 32 in parallel to the axis of rotation of the inner cylinder 17, produces on the perforated frictional surface 16 of the inner cylinder 17, in the region of the wedge-like gap 22, a defined suction zone 36.

The yarn take-off device 3 is composed of a pair of take-off rollers 37 and 38 mounted for rotation in the direction of respective arrows 39 and 40.

The feed roller 5, the fibre opening cylinder 8 of the individualizing device 1, the inner cylinder 17 and the take-off rollers 37,38 are driven by known, (not shown) means from the central drive of the spinning unit (not shown).

The outer cylinder 14 and the inner cylinder 17 have their respective axes of rotation 41 and 35 (Figures 1 through to 6). A plane passing through said two axes of rotation 35 and 41 is called first plane 42 to which a second plane 43 is perpendicular; the latter passes either through the axis of rotation 41 of the outer cylinder 14 (Fig. 2), or through the axis of rotation 35 of the inner cylinder 17. Figure 3 shows the first plane 42 as identical with the sheet plane while Fig. 4 shows the second plane 43 as identical with the sheet plane. The two planes 42,43 intersect with each other along an intersection line 44 which corresponds, e.g. in Figure 3, to the axis of rotation 41.

A perpendicular projection 45 of the longitudinal axis 29 of the transport portion 28 of the fibre supply duct 11 onto the first plane 42 (Fig. 3) includes an acute angle alpha with said intersection line 44. As experimentally ascertained, a preferred range of the angle alpha is from 5 to 35".

A perpendicular projection 45 of the longitudinal axis 29 of the transport portion 28 of the fibre supply duct 11 onto the second plane 43 (Fig. 4) includes also an acute angle beta, preferably of less than 15 , with the intersection line 44.

Each cross-section of the transport portion 28 of the fibre supply duct 11, which is perpendicular to its longitudinal axis 29, is a geometrical figure symmetrical with respect to the longer and the shorter axis of symmetry 46 and 47, respectively, which are perpendicular to each other; it results therefrom that the geometrical figure can be a rectangle (Figs. 2,5), ellipse (Fig. 6), oval, or the like.

The longer axis of symmetry 46 (Figs. 5. 6) includes an acute angle gamma with the first plane 42. As experimentally found out, the position of the fibre supply duct 11 is to be preferably chosen so that each line identical with the longer axis of symmetry 46 of each of cross-sections of the transport portion 28 of the fibre supply duct 11 may include an acute angle gamma of preferably less than 20 .

In operation, a fibrous sliver 48 withdrawn from a spinning can (not spinning) is conveyed into the fibre individualizing device 1 in which fibres are combed out of the sliver by the card clothing 10 and simultaneously accelerated whereby a continuous flow of individual fibres is formed. The fibre flow is characterized by a statistical mean velocity which is one of factors important for the subsequent deposition of fibres onto the inner frictional surface 15 of the outer cylinder 14, and, in the point of impact onto the frictional surface 15, by a certain straightness value along the longitudinal axis 29 of the transport portion of the fibre supply duct 11.

This position of fibres has to be necessarily maintained after the impact of fibres onto the inner frictional surface 15, while the fibres should be oriented substantially in the direction of generatrix of the outer cylinder 14.

For maintaining the desirable position of fibres in the fibre flow a subatmospheric pressure in the supply duct 11 is produced by the suction zone 36.

Fibres having a certain mean velocity can be deposited onto the rotating inner frictional surface 15 in the case only that the direction oftheirflow identical with the longitudinal axis 29 of the transport portion 28 of the supply duct 11 is chosen so that the perpendicular projection 45 of said axis 29 onto the first plane 42 may include an acute angle alpha with the intersection line 44, and that the perpendicular projection 45 of the axis 29 onto the second plane 43 may include an acute angle beta with the intersection line 44. Simultaneously it is desirable that the orientation of the fibre supply duct 11 characterized by the position of the longer axis of symmetry 46 relative to the first plane 42, may express one of preferred values of the corresponding range of angles.If the above conditions are complied with, the fibres are deposited onto the inner frictional surface 15 of the outer cylinder 14 substantially straight and advantageously so oriented that they form, due to successiva doubling, a continuous fibrous la y dr which, already under the mechanical control of the inner frictional surface 15, advances to the wedgelike gap 22.

In the mouth of the wedge-like gap 22, the fibres acted upon by the force of suction zone 36 defined on the perforated frictional surface 16, are densified to an open yarn end, and then, due to the effect of the two frictional surfaces 15, 16 they are twisted to yarn P to be withdrawn, along the axis of the wedgelike gap 22, by the take-off rollers 37, 38, and finally wound in a (not shown) take-up device onto a bobbin.

Owing to the above-mentioned advantageous orientation and straightness of fibres, arisen as early as during the deposition of fibres from the fibre flow onto the inner frictional surface 15 of the outer cylinder 14, a very strong and uniform yarn is produced.

The afore-described orientation of the transport portion 28 of the fibre supply duct 11, and particularly within the angle ranges as hereinabove set forth, makes it possible to define on the inner frictional surface 15 a relatively narrow region of fibre supply so that the spinning process meets high claims laid on the useful yarn properties.

If the defined position of the longitudinal axis 29 of the transport portion 28 of the fibre supply duct 11 is maintained, the required results are always obtained even if the cross-section of said portion 28 is another geometrical figure, provided the figure is symmetric with respect to its longer and the shorter axis of symmetry.

Claims (7)

1. Africtional open-end spinning apparatus, comprising a rotary outer cylinder having an inner frictional surface, an inner cylinder having a perforated outer frictional surface and mounted for opposite rotation in said outer cylinder, said two frictional surfaces being in a contactless proximity with each other whereby a wedge-like gap at the place of their nearest approach is formed therebetween, a suction nozzle arranged in said inner cylinder and defining by its mouth a confined suction field on said perforated frictional surface in the region of said wedge-like gap, and a fibre supply duct entering said outer cylinder from the exterior and having an outlet portion which is oriented toward the inner frictional surface of said outer cylinder movable to said wedge-like gap, wherein a first imaginary plane passes through the axis of rotation of the outer cylinder and the axis of rotation of the inner cylinder while a second imaginary plane passes through one of said axes of rotation of the two cylinders and is perpendicular to said first plane, wherein a perpendicular projection of the longitudinal axis of a transport portion of the fibre supply duct merging into a bevelled outlet portion of said c CL) onto said first plane includes an acute first angle with a line along which the two planes intersect each other, wherein the perpendicular projection of the longitudinal axis of a transport portion of the fibre supply duct onto the second plane includes an acute second angle with the first plane, wherein each of cross-sections of the transport portion of the fibre supply duct has two axes of symmetry perpendicular to each other and wherein the first plane includes an acute third angle with the longer of said axes.

2. An apparatus according to claim 1, wherein the acute first angle is within the range of from 5 to 35".

3. An apparatus according to claim 1 or 2, wherein the acute second angle is less than 15 .

4. An apparatus according to claim 1, wherein the acute third angle is less than 20 .

5. Africtional open-end spinning apparatus substantially as hereinbefore described with reference to Figs. 1 to 4 of the accompanying drawings.

6. An apparatus according to claim 5, but modified substantially as hereinbefore described with reference to Fig. 5 of the accompanying drawings.

7. An apparatus according to claim 5, but modified substantially as hereinbefore described with reference to Fig. 6 of the accompanying drawings.