US3901012A

US3901012A - Method of and device for processing fibrous material

Info

Publication number: US3901012A
Application number: US476471A
Authority: US
Inventors: Vaclav Safar
Original assignee: Elitex Zavody Textilniho
Current assignee: Elitex Zavody Textilniho
Priority date: 1973-06-07
Filing date: 1974-06-05
Publication date: 1975-08-26
Anticipated expiration: 1992-08-26
Also published as: CH580175B5; CH575019A5; CS189112B1; FR2232627A1; FR2232627B3; JPS5031139A; GB1456414A; DD113776A1; DE2424669A1; CH693874A4

Abstract

Method of and apparatus for processing fibrous material to yarn by cooperation of an electrostatic field. Fibers are caught after opening, are parallelized on a doubling means by the action of an electrostatic field and are continuously withdrawn therefrom by a rotating free end of yarn. The rotation of the free end of yarn is exerted by a twisting means acting upon the yarn to be formed beyond the zone of connection of the fibers to the rotating end of yarn.

Description

United States Patent Safar Aug. 26, 1975 [54] METHOD OF AND DEVICE FOR 141L284 11/1968 Corbaz ct a1 57/5891 PROCESSING FIBROUS MATERIAL 3,537,249 11/1970 Mayer v r i A .1 57/5889 3,552.112 1/1971 Chabot i 57/58.89 X

[75] In en r: Vaclav f Llberec, 3,665 695 5/1972 Amato r a r 57/5391 Czechoslovakia 16961300 10/1972 Mayer ct al 1 1 1 4 .1 57/5889 3,696,603 10/1972 Kotter et a1 r v 4 v 1 A 4. 57/5889 [73] Asslgnee: T zamdy 3,761148 10/1973 'nirower .r 57 34 R x strojirenstvi, generalni reditelstvi, Liberec, Czechoslovakia Primary Examiner-Donald E, Watkins [22] Filed: June 5, 1974 [21] Appl. No.: 476,471

{57] ABSTRACT [30] Foreign Application Priority Data Method of and apparatus for processing fibrous mate- June 7 1973 Czechoslovakia 4100.73 rial to yarn by cooperation of an electrostatic field. Fi-

. bers are caught after opening, are parallelized on a [52] US. Cl 57/5839; 57/5895 doubling means by the action of an electrostatic field [51 1 Int. Cl DOlh 1/12 and are continuously withdrawn therefrom by a rotat- {58] Field of Searchmm 57/5, 6, 34 R, 58159-5895, ing free end of yarn. The rotation of the free end of 57/773, 156 yarn is exerted by a twisting means acting upon the yarn to be formed beyond the zone of connection of [56] References Cited the fibers to the rotating end of yarn UNITED STATES PATENTS 23 Claims, 6 Drawing Figures 1107,4724 10/1963 Arshmov et a1. 57/7753 X PATENTEI] M182 6 I975 SHIT E OF 4 PATENTEUAUBZBWB 2.90 1.012

METHOD OF AND DEVICE FOR PROCESSING FIBROUS MATERIAL The present invention relates to a method of and a device for processing fibrous material to yarn by the action of static electricity.

Many prior methods of processing fibrous material to yarn are known. The most important feature, according to which the different prior methods are distinguished, consists in the manner of reinforcing the silver of fi brous material formed by a certain linear sequence of fibers mutually connected in said silver. Several methods hitherto known use adhesive means by means of which the fibers in the silver are mutually linked, whereby their coherence and the strength of the fibrous silver thus formed are secured. The adhesive means might be removed later, e.g. by washing, or it becomes a permanent component of the yarn forming the final product of the fibrous body. In other methods, using this kind of reinforcing of fibrous material, a component formed of thermoplastic fibers is used, by means of which cohesion of a further component or components into yarn as a final product of fiber processing is achieved upon plastifying said thermoplastic fibers. Those yarns have certain specific properties and fields of application corresponding thereto. A certain disadvantage of yarns thus produced consists in their relative costliness caused by using adhesive means and by the intricacy of its manufacturing device employed.

The most widespread method of reinforcing a silver of fibrous material hitherto known consists in reinforcing the sliver by twisting, which may be performed in various manners. Twist is imparted to the yarn either by rotating a yarn winding, as e.g. upon conventional ring spinning (in a ring'traveller system), or by rotation of an open end of yarn being formed, or possible by alternating twisting a fibrous sliver in both directions, whereupon a so-called false twist is formed, in which regular alternation of yarns with left and right twist direction is obtained. Between those sections, a certain twistless section is encountered, whereby the final product i.e. the yarn is disturbed as to its appearance and as well from the viewpoint of its properties, particularly its strength. The twisting of an open yarn end is performed in certain cases in a purely mechanical manner, including joining fibers to the rotating fibrous silver, which is withdrawn, upon twisting, through the axis of the rotary body. In the pneumomechanical method, a rotary spinning chamber is particularly used, into which there are fed fibers separately by means of an air stress exerted by underpressure (partial vacuum) in said spinning chamber, and deposited about the circumference thereof in the form of a ribbon in a different sequence from that existing before in the fibrous material to be processed. The fibers deposited in the ribbon inside the spinning chamber are continuously withdrawn after being joined to and twisted about the open yarn end and withdrawn through the axis of rotation of the spinning chamber in the form of yarn. Further methods are known, in which the open yarn end is twisted by means of a turbulent processing fluid, mostly an air vortex, or possibly a rotating electrostatic field.

The disadvantage of the known manufacturing method of yarn in a rotary spinning chamber consists particularly in its limited output; this is caused by centrifugal forces acting upon the yarn upon its withdrawal from the collecting surface in view of the fact that the diameter of the spinning chamber is chosen with a certain relation to the length of the fibers to be spun. In this method, a further disadvantage is encountered which consists in the reduced strength of the yarn produced in the rotary spinning chamber.

In methods using a turbulent processing fluid for twisting, both the reduced strength of yarn as well as its unevenness which causes an unattractive appearance thereof, are serious disadvantages.

The so-called electrostatic method of spinning, i.e. twisting fibers in an electrostatic field, is hitherto known in several modifications. According to one modification of that method, the fibers are fed in a separated condition transversely to the spot electrode and are straightened thereupon by another field formed by the twisting spindle.

According to another modification of this spinning method, the fibers are fed in separated condition through an electrode in the forth of a tube in the direction of its axis to a twisting spindle forming the other electrode.

The common feature of those two modifications of the hitherto known electrostatic spinning method consists in straightening fibers between the twisting spindle forming one electrode or pole, and the other electrode or pole. The fibers are spun into the yarn in the same sequence as they are fed from the fiber separating element, and the flow of fibers is not interrupted between the open rotating yarn end and the separating element, i.e. the fibers move even during their straightening from the fiber separating element to the twisting electrospindle. Due to that, the sequence of fibers cannot be intentionally changed.

The common disadvantage of the above modifications of the electrostatic spinning methods consist in the inconsistency of the different actions of both the electrostatic and mechanical forces simultaneously acting upon the fiber upon spinning it into yarn. The joining of fibers in this method is to be performed in separated condition, i.e. upon separating the fibrous material to separate fibers. Otherwise, it would not be possible efficiently to straighten the fibers in the electrostatic field. Due to the required speed of spinning, a high voltage value is necessarily applied in the electrostatic field of this method, due to the speed of the fiber flow fed to the yarn twisting point, However, the action of the electrostatic forces upon the fibers is very short, and thus the said forces can overcome the mechanical ones acting upon the fibers, as e.g. inertia, natural fiber shrinkage, as well as upon aerodynamic forces caused by the high velocity of the fibers and the appurtenant components of the processing device, only with difficulties. The higher the spinning speed, the more unfavorable is the action of the inconsistency between the electrostatic forces and the mechanical forces upon the degree of straightening and the evenness of the resulting yarn. It has been proved by experiments, that the fibers in the said devices at rest, i.e. at that time at which the above mentioned mechanical forces do not act but with the electrostatic field in action, are correctly straightened, this being substantially disturbed upon starting by the action of both mechanical and aerodynamic forces, as mentioned above.

A further known method of spinning fibers consists in introducing fibers into a rotary electrostatic field, in which said fibers are twisted. The disadvantage of this method consists in the small value of the electrostatic forces in view of those required to exert a sufficient twisting effect necessary for spinning fibers into a yarn of sufficient strength.

A method of forming twisted yarn in which the spearated fibers are deposited in a depositing zone on to a movable surface and are fed by means thereof into a withdrawing zone in which said fibers are twisted about the axis of the yarn by frictional contact with a movable surface and a further reversing surface which closes or presses the fibers in said withdrawing zone, respectively, is known. The auxiliary means against retaining the fibers on the movable surface are formed either by an electrostatic field or by a sucking effect, said movable surface being provided with perforations.

It is possible in that method to spin fibers at high speed, and particularly to twist them by reversing frictional surfaces. However, there is a disadvantage which consists in that it is not possible to impart a precise and constant twist to the yarn under operational conditions. The twist variation and its unquaranteed degree within the normal limits and practice substantially affects the strength of the yarn and a reduction of its quality and usefulness. This disadvantage is not reduced even by simultaneously using twisting devices for false twist behind the frictional twisting device. Even that method is disadvantageous in certain cases wherein the movable surface for transferring fibers has defined zones for depositing and withdrawing fibers. This is the case particularly when, requiring high spinning speed, which a considerable quantity of fibers is fed upon the twisting element, such deposition on the movable surface being necessarily with the fibers in separated condition.

Under such conditions, the limiting of the space for feeding fibers and for depositing them on to the movable surface also entails a limiting of the output or a reduction of yarn quality, since for a suitable depositing of fibers in straightened condition a shorter time is available in proportion to increased transporting speeds of the fibers in a limited space for feeding fibers and retaining them to the movable surface. The defining of the fiber depositing zone makes it impossible to feed fibers e.g. to the whole movable surface, to form new fiber sequences there, or to perform thereon a more thorough blending and a more even fiber layer, e.g. by means of cyclic doubling. The method of twisting yarn by frictional contact with a movable surface does not make it possible to form these surfaces with a curved profile for the purpose of better adhesion of the fibers on the surface and thus achieving a more consequent straightening of the fibers between the poles for the purpose of improving the properties of the produced yarn. It is also disadvantageous since twisting by frictional contact eliminates the application of doubling means, in which there is a free space between the poles of the electrostatic field in which the fibers are retained and fed in straightened condition to a twisting element by the effect of said field, whereupon a simplification of the machine construction can be achieved.

A further method of processing fibrous material is known, in which a sliver of fibers is processed to yarn, said sliver being fed to a twisting element in opened condition, the separate fibers being deposited beside each other transversely to their longitudinal axis and being reversingly wrapped in the twisting zone and thereafter withdrawn in the form of yarn. The depositing of fibers and their arrangement beside each other is performed on a conveying link, which is movable transversely to the longitudinal axis of the fibers. The fibers are deposited in straightened condition on to the conveying link in which they are secured by appurtenant retaining element in form of pins, needles, projections or similar elements.

The limitations and disadvantages of this method of producing yarn consist namely in that the fibers deposited beside each other must be secured in straightened condition on a conveying link by mechanical retaining means in the form of needles, pins, and similar elements. Thus the passive resistance against twisting the sliver increases, and the withdrawal of fibers from the conveying link upon wrapping is simultaneously made more difficult, said wrapping being made oppositely for that reason. Also the deposition of fibers on to the conveying link and their arrangement and retaining beside each other in straightened condition by means of a depositing device is difficult and limited in its output. Therefore, it is necessary in certain cases to use for one twisting element a plurality of depositing devices. The The deposition of fibers beside each other is also disadvantageous for certain cases from the viewpoint of the properties of the final product, i.e. the yarn, as through blending of fibrous material and the forming of new sequences of fibers of high evenness is not possible. With that method, it is impossible, e.g. to use the principle of cyclic redoubling of separated fibers, which secures a higher evenness of yarn due to more thorough blending of fibers from the separate parts of the fibrous material.

The method of processing fibrous material to yarn according to the present invention has the purpose of reducing the above-mentioned disadvantages and insufficiencies to a minimum by making possible a higher velocity of processing fibrous material while simultaneously achieving a higher quality of the resulting product, i.e. yarn, according to the properties required.

In accordance with the method of processing fibrous material to yarn according to the present invention, the fibers being opened, and after being opened are retained and made parallel on a doubling means by the action of an electrostatic field and are continuously withdrawn therefrom by the rotating open yarn end, the rotation of which is performed by a twisting means acting upon the yarn to be formed beyond the section in which fibers are joined to the end of the yarn.

The device for performing the method according to the present invention consists particularly in that behind the fiber separating device for the fibrous material there is mounted a doubling means formed by the poles of a source of static electricity, the axis of rotation of the twisting means being directed toward one of said poles, said twisting means acting upon the yarn behind the point ofjoining fibers to the yarn end.

Further features of the method and device according to the present invention are described in the following specification and are shown in the accompanying drawings, in which:

FIG. 1 is a view in vertical section ofa first illustrative embodiment of the device for processing fibrous material into yarn according to the present invention;

FIG. 2 is a view in vertical section of a second embodiment of the device for processing fibrous material to yarn according to the present invention;

FIG. 3 is a schematic view in plan of the embodiment as shown in FIG. 2;

In the first embodiment shown in FIG. 1, the device according to the present invention is formed by a known device 1 for separating fibrous material 20, the output 1' of device 1 being continued by a guiding tube 2 with a widened end, of which the inlet part 2 is provided with a pulley 3. The pulley 3 is embraced by a belt 4 transmitting thereto rotary motion from a driving means (not shown), and distributing ribs 2" for imparting rotary motion to fibers l3 and forming a so-called cyclic doubling of fibers on the circumference of poles or electrodes 7, 8.

Tube 2 is mounted rotatably in a frame 5, which surrounds space 4 of the electrostatic field 6 formed by the two electrodes 7 and 8, such electrodes being connected to a source 9 of high voltage, and mounted on a rotary shaft 10, shaft 10 is provided on its lower end with a pulley 11 which is embraced by belt 12 transmitting thereto a rotary motion from a driving means (not shown). The electrodes 7 and 8 have the shape of bodies of revolution, and between their spaced confronting ends fibers 13 are straightened and deposited to sequences disposed about their circumference. On the outer side of the end of electrode 8, a twisting element 14 is rotatably mounted at its immediate proximity in frame 5, said means being provided at its lower end with a pulley 15, which is in contact with a friction disc 16 imparting a rotary motion to twisting element 14 via pulley 161 and belt 162 driven from a driving means which is not shown. The end of yarn 17 passes through twisting means 14, by means of which the ends of the fibers are withdrawn from the end of electrode 8 at a certain point to which the electrodes 7 and 8 arrive during one revolution of the circumferential edge of electrode 8. The withdrawn fibers 13 are wrapped on to the end of yarn I7 and are twisted to yarn by a twist ing element. The finished yarn 17 is withdrawn by a pair of withdrawing cylinders 18 and is wound onto a bobbin 19 which is mounted, together with the withdrawing cylinders, apart from the frame 5 of the device. On frame 5 there may be situated in the proximity of electrode 8, or twisting means 14, respectively, yarn diameter limiting means 600, e.g. a projection, a lug or a similar element made either of non-conductive material, or also of conductive material. However, in the latter case an influence upon the electrostatic field 6 cannot be excluded.

In the second embodiment, shown in FIGS. 2 and 3, the device according to the present invention is formed by a known drafting mechanism 21, of which the first pair of rollers 210 feeds the fibrous material 20, the next pair 2!] drafts it and the last pair 212 separates it. Below the drafting mechanism 21, Le. below its last pair of rollers 2l2 there is mounted a device by means of which an electrostatic field 6 is formed. This device consists of two electrodes 7 and 8' connected to a source of high voltage 9'. Electrodes 7' and 8' are mounted on a rotary shaft 10 mounted in the machine frame 22, shaft 10' being provided at its lower end and with a pulley ll, embraced belt 12, by means of which there is transmitted to shaft 10 a rotary motion from a driving means (not shown). Electrode 7' is formed in this case by a disc shaped plate, and pole 8' is formed by an outer ring which surrounds a non-conductive plate 8' on the upper side of which the electrostatic field 6 is situated in the annulus between electrodes 7', 8'. Electrode 7' with center M (FlG. 3) may also be made in the fon'n of a cylindrical or conical projection coaxial to shaft 10, whereby an advantageous course of the gradient of the electrostatic field, and thus higher efficiency upon straightening fibers 13 is achieved. Also plate 8' may be of planar form, as shown in the drawing, or may also have another rotary shape of arbitrary kind, e.g. a cone or a similar shape. Beside electrode 8' there is mounted at its immediate proximity a twisting means 14', through which there passes the end of yarn 17 by which are withdrawn at a certain point, through which pass during one revolution of electrodes 7', 8 all points of the circumferential edge of electrode 8', the ends of fibers 13 on electrode 8' which are wrapped about the end of yarn l7 and twisted by means of twisting means 14' to yarn 17. The twisting means 14' is given a rotary motion by means of a known device (not shown).

The yarn 17 is withdrawn from the twisting means 14' by a pair of withdrawing rollers 18 and is wound onto bobbin [9. The axis of the twisting means 14 forms with fibers R3 in the electrostatic field 6 at the point of their connection with the end of yarn 17 an angle alpha of a value within the range from 0 to 80. The pole 8' which is situated at the proximity of twisting means 14'. may advantageously be grounded, and thus twisting means 14 is not affected by the electrostatic field. The angle alpha influences the direction of connecting fibers to the rotating free yarn end. so that it is possible to change suitably the properties of the yarn to be manufactured.

The device according to the present invention the third embodiment thereof shown in FIG. 4 consists of a known fiber separating device 1 with an outlet 1' for opening fibrous material 20, which is directly connected to the space of electrostatic field 6", surrounded by a housing 6a. Beside device 1 for opening fibrous material 20 there is mounted a vessel 30 which contains an adhesive agent. Inside vessel 30, there is mounted a pad roller 31 which is partially dipped into said adhesive agent and is in permanent contact with a squeeze roller 32. Between vessel 30 and housing 60 of the space of electrostatic field 6' there is mounted a guiding roller 33. Thread 34, unwound from a winding (not shown) is guided between pad roller 3! and squeeze roller 32 and via guiding roller 33 into inlet opening 61 of housing 60 of the space of electrostatic field 6', which is disposed beside outlet 1' of device 1 for opening fibrous material 20 into the space of electrostatic field 6'. The electrostatic field is formed by two electrodes 7b, 8!; connected to a high voltage source 9', to said electrodes 7b, 8b there are fed fibers 13 from outlet 1' of the device I for opening fibrous material 20. Poles 7b and 8b are made in the form of endless movable tapes driven from a drive source (not shown). in the space 6' of the electrostatic field between poles 7b and 8b, fibers 13 are straightened and guided in the direction of arrow 5 by movement of electrodes 7b and 8b in the direction towards thread 34, by which they are withdrawn by the common action of twist, adhesive agent, and the movement of said thread in the direction of arrow R. Behind outlet 62 of housing 60 of the space 6' of the electrostatic field there is mounted a twisting means 14, through which thread 34 with fibers l3 wrapped therearound passes. The twisting means 14 is in contact with driving rollers 35 provided at their ends with a pulley 36 embraced by belt 37, by means of which a rotary motion is imparted to said twisting means via driving rollers 35 from a driving source (not illustrated). In the twisting means 14 the fibers 13 are twisted around thread 34, whereby the resulting yarn 38 is formed, which is withdrawn by a pair of withdrawing rollers 18, the yarn 38 being wound onto bobbin 19.

The device according to the invention in the fourth embodiment as shown in FIG. 5 consists of a known device for opening and separating fibrous material 20, which is continued by an outlet channel 1', opening into a homogenizing space 60 for homogenizing the freely dispersed fibers 13 by retardation caused by the fact that the cross section of homogenizing space 60 is at least five times larger than the cross section of outlet 1' of separating device 1. The homogenizing space 60 may also be equipped with the nozzle 70, which is connected by a conduit 71 to a source of processing pressure fluid (not shown).

The opened lower part of the homogenizing space 60 is continued by a plate 80 of non-conductive material, at the circumference of which there is located pole 8d and in its center electrode 7c, which are both connected to a high voltage source 9, thus forming and electrostatic field 6c therebetween. Beside electrode Be a twisting means 140 is situated at the immediate proximity thereof, said twisting means 14c being imparted rotary motion by a known device (not shown) and yarn 17 being passed therethrough which, by rotation imparted thereto by twisting means 14c wraps fibers 13 assembled on plate 8c between electrodes 7d and 80 about its end and the yarn 17 thus formed is withdrawn by means of a pair of withdrawing rollers 18 and further wound onto bobbin 19. Shaft d, on which pole 7c with plate 8d are mounted, is mounted in frame 22 and is provided with a pulley ll, embraced by belt 12, by which the rotary motion from a source (not shown) is transmitted to shaft 10d.

The device according to the present invention in the fifth embodiment shown in FIG. 6 consists of a feeding channel 1' connecting a known, not shown device for separating fibers, e.g. a carding machine with a homogenizing space 60 for assembling separated fibers 13, in which electrodes 7f, 8f which are connected to a high voltage source 9, are guided longitudinally. Beside electrodes 8f there are mounted twisting means 14 in the immediate proximity thereof, a rotary motion being imparted to twisting means 14e by a known device (not shown). Yarn 17 passes through twisting means 14c, and wraps about its end fibers 13 by rotation thereof, said fibers being straightened between electrodes 7f and 8f, and is continuously withdrawn by pairs of withdrawing rollers 18 and wound onto a not shown yarn winding.

Contrary to the devices as mentioned before, and as shown in FIGS. 1 to 5, in which for each twisting means 14: there is used an independent device for separating fibers and an independent homogenizing space for processing the fibers by means of an electrostatic field, the embodiment as shown in FIG. 6 has a common homogenizing space 60 for a group of twisting means 14c, as well as common electrodes 7f and 8f in the form of belts driven from a known source (not shown) and passing in the direction of arrows S,S' longitudinally through homogenizing space 60, as well as a common device for separating the fibers and a common feeding chennel 1'.

In the proximity of the twisting means Me, in the direction of movement of electrodes 8e, there is mounted a sucking tube 63, which is connected by a connecting channel 64 to a sucking channel 65, which is continuous along the whole machine and is connected to a known underpressure (vacuum) source (not shown). Inside the connecting channel 64 there is mounted a closing element 68, e.g. a valve, a flap, a side valve etc., which is controlled via a conduit 67 in a manner known from automation and control means from feeler 66 which senses from variations of yarn tension, the breakage of yarn 17.

The devices according to the present invention perform the method according to the present invention as follows:

ln the embodiment as shown in FIG. 1, the fibrous material 20 is fed into the device 1 for opening fibers, in which the individual fibers 13 are separated, said fibers passing through outlet 1' into the rotating guiding tube 2, from which they slide down to the surface of ro tating electrode 7 and are fed into the space of electrostatic field 6 between the two rotating electrodes 7, 8 between which fibers 13 are rearranged and striaghtened in stationary condition by the action of the gradient of the electrostatic field.

By means of distributing ribs 2" fibers 13 are distributed about the circumference of electrodes 7, 8, thus forming a new sequence by the so-called cyclic doubling of the separate elementary fiber layers, in a manner similar to that performed in a spinning chamber.

By the rotation of electrodes 7,8, fibers 13 are gradually fed to the rotating twisting means 14, where the free yarn end 17 projecting therefrom withdraws the fibers and wraps them around it and twists to yarn 17, which is thereupon withdrawn from twisting means 14 either at a constant or a varying speed by means of withdrawing rollers 18 and wound onto bobbin 19, when frame 5 is provided with means 600, e.g. in the form of a projection, a lug or a similar part, this means acts upon the yarn end projecting from twisting means 14 to limit its diameter, whereby a better quality of produced yarn is achieved.

ln the embodiments as shown in FIGS. 2 and 3, the fibrous material 20 is at first drafted and separated by the appurtenant roller pairs 211, or 212, respectively, of drafting mechanism 21, and fibers 13 made of fibrous material 20 by separating are then brought into the space of electrostatic field 6 in which they are rearranged between electrodes 7' and mounted on a non-conductive plate 8' which rotates with a driven shaft 10, and are straightened by the action of a gradient of the electrostatic field 6. The direction of movement of fibers 13 from the pair of rollers 212 might be in the direction of shaft 10 or in a direction inclined to the length of said shaft, the theoretical point of contact of the fibers being either in the center M of electrode 7 or at an arbitrary distance therefrom on electrode 7' or on the non-conductive plate 8'. Plate 8' may have a planar or a conical shape, or the shape of any body of revolution. Fibers 13 in the electrostatic field arranged as mentioned above. are fed grudaully. by rotation of the electrodes 7', 8' to the twisting means 14 performing a rotary motion and are withdrawn therefrom by the free end of yarn l7 projecting therefrom and wrapped thereabout, and thereafter are twisted to the yarn inside the twisting means 14, said yarn being withdrawn either at a constant or a varying speed by withdrawing rollers 18 from the twisting means and thereafter being wound onto bobbin 19.

In the embodiment shown in FIG. 4, the fibrous material is fed to device 1 for opening and separation, and therefrom the separated fibers l3 are fed through outlet 1' into the space of the electrostatic field 6' to the electrodes 7b and 8b in the form of endless movable belts, where they are re-arranged due to the gradient of the electrostatic field 6' and straightened in stationary condition. Thread 34 is padded between the padding roller 31 and the squeeze roller 32 with an adhesive agent from vessel 30 and are guided over guiding roller 33 through inlet 61 into the space of electrostatic field 6, moving therein in the direction of arrow R. Fibers 13 which are straightened and rearranged between electrodes 7b and 8b are brought to the thread 34 by their movement in the direction of arrow S, and are wrapped in the twisting means by the action of the adhesive agent, as well as by movement of the thread 34 in the direction of arrow R by its twisting inside the rotating twisting means 14. In that manner, thread 34 ohtains the character of yarn core and is changed to false twist yarn. Behind the twisting means 14, this twist is anulled and on the surface of the yarn 38 thus formed there remain fibers I3 withdrawn from the electrodes 7b, 8b of the electrostatic field 6 adhered to and wrapped therearound. The resulting yarn 38 is withdrawn by means of withdrawing rollers 18 and are wound onto bobbin 19. In this method, the free end of yarn 17 is formed by staple fibers and the twist thus formed on the yarn is true, while the yarn core is without twist.

In the embodiment as shown in FIG. 5, the fibrous material 20 is fed into the device 1 for opening and separating fibers, and the separate fibers 13 pass therefrom through outlet 1' into the homogenizing space 60, in which they are freely dispersed and retarded in that condition to at least one fifth of their speed at the outlet. The separating device 1 thus making the flow of fibers 13 more even and forming a homogenous fiber blend. This effect can be supported by further means, eg nozzle 70, from which a flow of pressure fluid fed through supply conduit 71 from a not shown source causes an intensive turbulence inside homogenizing space 60 and a blending of fibers coming to the proximity of poles 72, 8d against the fiber flow entering through outlet 1' into homogenizing space 60. In this manner, an effect similar to the so-called cyclic doubling shown in FIG. I is achieved. The evenness of the fiber flow is better the larger is the homogenizing space 60. It is suitable, for the cross section of the homogenizing space 60 to be, relative to the cross section of outlet 1' from the separating device I, at least five times larger; a more intensive fiber blending may be secured by the use of the flow of pressure fluid from nozzle 70 into the homogenizing space 60.

The fibers 13 are straightened by the effect of the electrostatic field 6 between poles 72, 8d on conical plate 8e and continuously withdrawn therefrom by the rotating free end of yarn 17, to which a rotary motion is imparted by twisting means 14. The resulting yarn I7 is withdrawn by a pair of withdrawing rollers 18 and is wound onto bobbin 19. The conicity of plate 8e may be of various values according to the need of the required technological conditions, and may have a value within the range from 0, in which case the plate is planar, as shown in FIGS. 2, 3, up to in which case an inner space of cylindrical shape is formed. The surface of plate 8e might be also suitably shaped for the purposed of achieving a better straightening of the fibers upon piecing, e.g. curved, as shown in FIG. 6.

In the embodiment of FIG. 6, the fibrous material 20 which is opened and separated by means of a not shown device, is fed through feeding channel 1 into a homogenizing space 60, which is common for two or more twisting means 14, withdrawing means 18 and winding means 19 for the yarn. The feeding channel 1' may be in the form of a slot or a tube of continuous width, as shown in FIG. 6, or may be divided about its width into several partial feeding channels 1' of eg circular cross section, which open into a common homogenizing space 60. The supplied fibers 13 may be subjected in the homogenizing space 60 to homogenization in a manner similar to that shown in FIG. 5, or by another known blending device, e.g. in a mechanical manner, by means of a rotating propeller inside the homogenizing space 60. In view of the fact that the homogenizing space 60 may have considerably larger dimensions than a homogenizing space for one separate twisting means, as shown in FIG. 5, a more intensive blending of fibers 13 is achieved thereby as well as a better evenness of their flow to the exit, or their arrangement into a new sequence between the electrodes 7f, 8f, respectively.

The fibers 13 are in straightened condition, between electrodes 7f, 8]" continuously fed in the direction of

arrows

8,8 to the separate twisting means 14, which are situated in the proximity of electrode 8f and impart rotation to the free end of yarn 17, onto which are wrapped the fed fibers 13, whereby yarn is formed, which is withdrawn by a pair of withdrawing rollers 18 and wound in a known manner and by a known device onto an arbitrary winding (not shown). The opening and separating device might be made either as a group device for a plurality of twisting means 14 and withdrawing means 18, or a central device for the whole machine, or possibly also beside the machine as an independent device. Such an independent opening and separating device is e.g. a carding machine, from which are pneumatically doffed the separated fibers 13, which are subdued in the homogenizing space 60 of the device according to the present invention to uniforming and processed by cooperation of the electrostatic field as specified above.

In FIG. 6, a device 68 for sucking ofi' fibers which are not spun into the yarn, is diagrammatically shown. Such a device might be made also in all other alternative embodiments of the spinning device according to the present invention, as eg in the embodiments as shown in FIGS. 1 to 5. The operation of this device is in the embodiment in form of example as follows:

In the proximity of twisting means 14, is in the direction of movement of pole 8f there mounted a sucking device tube 63', for sucking off fibers 13 which have not been spun into yarn 17, particularly upon breakage of yarn 17. These fibers are transported through connecting channel 64 and further through sucking channel 65 into an accumulating space (not shown) mounted on the machine or apart therefrom. The sucking device 63 might be in action for the whole time of operation of the machine in all spinning heads, i.e. said device is neither switched off nor controlled by any means. In that case a smaller part of fibers 13 which have not been spun in or not caught up by a free end of yarn 17 is sucked off. For improvement of this device, and for saving power, it is possible to open the connecting channels 64 only in the case when feeler 66 emits the due signal by means of a transmitting member 67 to the closing element in case breakage of yarn 17 occurs. Upon yarn breakage, the not spun fibers 13 are sucked off. As soon as the yarn is pieced again, the closing element 68 closes the appurtenant connecting channel 64.

The advantage of the method according to the present invention as well as of the device for performing said method consists in that it is possible to achieve by means thereof a controlled connection of the fiber to the yarn being formed. As the fiber are relatively at rest, it is possible to achieve their correct straightening, thus considerably mitigating the influence of mechanical and aerodynamical forces, which would unfavorably act upon staightening fibers during movement thereof.

A considerable advantage of the method of processing fibrous material according to the present invention is the independent preliminary preparation of fibers for being spum by means of electrostatic forces, apart from twisting. Thus it is possible to use on the one hand a twisting means, e.g. a spindle of small mass for twisting at high speed in the axis of the yarn independently from the electrostatic field, and particularly it is possible to process to yarn fibers, which have been subdued to opening and separation by an arbitrary means most suitable for this purpose.

Thus, it is possible to make a group opening device for two or more twisting means, or a central opening device common to the whole machine from which the fibers are transported in separated condition into the electrostatic field and prepared therein for spinning in the separate spinning units. Thus, the construction of the machine can be simplified and the production costs reduced.

Fron the viewpoint of automation of the whole spinning technology, the method according to the present invention makes it possible directly and continuously to connect an independent opening and separating device, as e.g. a carding machine to a spinning machine and to form thereby already on the base of the known state of art a continuous spinning process.

A further advantage of the method according to the present invention consists in making it possible to spin yarn with a predetermined and constant twist by using spindles with a safe gripping of the yarn.

The separate embodiments of the device for performing the method according to the present invention, as mentioned above in the specification, by no means cover the whole scope of the method of and device for performing the present invention. lt is possible to make still further many modifications obvious to those skilled in the art and falling within the scope of protection of the method according to the present invention.

What is claimed is:

l. A method of processing fibers to a yarn by cooperation of an electrostatic field, comprising opening the fibers, retaining and parallelizing the opened fibers on a doubling means by the action of an electrostatic field, and continuously withdrawing the parallelized fibers from the doubling means at a zone in which the fibers are connected to a rotating free end of yarn, the rotation of the free end of yarn being performed by a twisting means acting upon the yarn being formed beyond the zone at which the fibers are connected to the rotating free end of yarn.

2. A method as claimed in claim 1, wherein the twisting means is separate and apart from the means forming the electrostatic field.

3. A method as claimed in claim 1, wherein the para]- lelized and straightened fibers are fed to the spinning point of the twisting means in a direction transverse to the longitudinal axis of the fibers.

4. A method as claimed in claim 1, wherein the axis of the fibers is parallel to the axis of the yarn at the spinning point.

5. A method as claimed in claim 1, wherein the axis of the fibers forms an angle with respect to the axis of the yarn.

6. A method as claimed in claim 1, wherein the rotating free end of yarn is thrust into contact with the doubling means by the action of electrostatic forces.

7. A method as claimed in claim 1, comprising limiting the diameter of the rotating free end of the yarn by contacting it with a fixed yarn engaging means.

8. A method as claimed in claim 1, wherein the direction of rotation of the free end of yarn is parallel to the direction of movement of the doubling means.

9. A method as claimed in claim 1, wherein the direction of rotation of the free end of yarn is opposite to the direction of movement of the doubling means.

10. A method as claimed in claim 1, wherein the sequence of fibers on the doubling means is different from the sequence of fibers in the fibrous material before its processing.

11. A method as claimed in claim 1, wherein the sequence of the fibers and the group situated on the doubling means is formed by random distribution of fibers on at least 30% of its surface.

12. A method as claimed in claim 1, wherein the sequence of fibers in the group on the doubling means is formed according to a predetermined program.

13. A method as claimed in claim 1, comprising passing the fibers after they have been separated through a homogenizing space, and increasing the evenness of flow of the fibers before depositing them on the doubling means by retarding their flow to at least one-fifth of their speed at the exit from the fiber separating device.

14. A method as claimed in claim 1, wherein the spinning of fibers from the electrostatic field is performed by fastening them to a continuous thread and subsequently twisting them around said thread.

15. Apparatus for processing fibers to yarn by cooperation of an electric field comprising means for opening the fibers, means for retaining and parallelizing the opened fibers on a doubling means by the action of an electrostatic field, and means for continuously withdrawing the parallelized fibers from the doubling means, means for rotating the free end of a yarn, said last named means including a twisting means acting upon the yarn to be formed beyond the zone at which the parallelized fibers from the doubling means are connected to the rotating end of yarn.

16. Apparatus as claimed in claim 15, wherein the doubling means is mounted beyond the fiber opening device and is formed by opposed electrodes connected to a source of static electricity, and wherein the axis of rotation of the twisting means acting upon the yarn beyond the zone of connecting the fibers to the free end of the yarn is directed toward one of said electrodes.

17. Apparatus as claimed in claim 16, wherein said electrodes are formed by elements which are at least parts of bodies of revolution.

18. Apparatus as claimed in claim 16, wherein the electrodes comprise at least portions of continuous belts.

19. Apparatus as claimed in claim 16, comprising a device for forming a sequence of fibers according to a predetermined program disposed between the fiber opening device and the electrostatic field.

20. Apparatus as claimed in claim 19, wherein the device for forming a sequence of fibers according to a predetermined program is made in the form of a homogenizing space having a cross sectional area which is at least five times greater than the cross sectional area of the exit passage from the fiber separating device 21. Apparatus as claimed in claim 20, comprising a nozzle opening into the homogenizing space for feeding a processing fluid which homogenizes the flow of fibers through said homogenizing space.

22. Apparatus comprising a plurality of processing units as defined in claim 19, and wherein the homogenizing space is common to the twisting means of said plurality of processing units.

23. Apparatus as claimed in claim 16, wherein the axis of the twisting means forms an angle within the range from 0-80 with respect to the longitudinal axis of the fibers at the point of spinning.

Claims

1. A method of processing fibers to a yarn by cooperation of an electrostatic field, comprising opening the fibers, retaining and parallelizing the opened fibers on a doubling means by the action of an electrostatic field, and continuously withdrawing the parallelized fibers from the doubling means at a zone in which the fibers are connected to a rotating free end of yarn, the rotation of the free end of yarn being performed by a twisting means acting upon the yarn being formed beyond the zone at which the fibers are connected to the rotating free end of yarn.

3. A method as claimed in claim 1, wherein the parallelized and straightened fibers are fed to the spinning point of the twisting means in a direction transverse to the longitudinal axis of the fibers.

20. Apparatus as claimed in claim 19, wherein the device for forming a sequence of fibers according to a predetermined program is made in the form of a homogenizing space having a cross sectional area which is at least five times greater than the cross sectional area of the exit passage from the fiber separating device.

21. Apparatus as claimed in claim 20, comprising a nozzle opening into the homogenizing space for feeding a processing fluid which homogenizes the flow of fibers through said homogenizing space.

23. Apparatus as claimed in claim 16, wherein the axis of the twisting means forms an angle within the range from 0*-80* with respect to the longitudinal axis of the fibers at the point of spinning.