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Title:
NEEDLED YARN PRODUCING DEVICE AND A METHOD OF PRODUCING NEEDLED YARN
Document Type and Number:
WIPO Patent Application WO/2009/148342
Kind Code:
A1
Abstract:
The subject of this invention is a needled yarn producing device and a method of producing needled yarn. More specifically, this invention refers to a device and a method of producing needled yarn out of a band of fibres that are formed in a linear way, designed for various technical applications.

Inventors:
WISNIEWSKI, Marek (WISNIEWSKI Marek, ul. SW. Franciszka z Asyzu 76 m 5, Lodz, PL-93-479, PL)
PODSIELIK, Wladyslaw (Ul. Piasta Kotodzieja 15/22, Lodz, PL-92-430, PL)
WOJTYSIAK, Jan (Ul. Przytulna 11, Krzywiec, PL-95-070, PL)
CZEKALA, Lukasz (Ul. Szafera 6/11, PL-92-306, PL)
Application Number:
PL2009/000063
Publication Date:
December 10, 2009
Filing Date:
June 05, 2009
Export Citation:
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Assignee:
INSTYTUT TECHNOLOGII EKSPLOATCJI - PANSTWOWY (lnstytut Badawczy, ul. K. Pufawskiego 6/10, Radom, PL-26-600, PL)
WISNIEWSKI, Marek (WISNIEWSKI Marek, ul. SW. Franciszka z Asyzu 76 m 5, Lodz, PL-93-479, PL)
PODSIELIK, Wladyslaw (Ul. Piasta Kotodzieja 15/22, Lodz, PL-92-430, PL)
WOJTYSIAK, Jan (Ul. Przytulna 11, Krzywiec, PL-95-070, PL)
CZEKALA, Lukasz (Ul. Szafera 6/11, PL-92-306, PL)
International Classes:
D02G3/00; D04H18/02
Foreign References:
US20030194528A1
DD220062A1
US6857170B2
Attorney, Agent or Firm:
TWARDOWSKA, Aleksandra (Jan Wierzchon & Partners, Patent and Trade Mark Attorneysul. Zurawia 47/49, Warszawa, PL-00-680, PL)
Download PDF:
Claims:

Patent claims

1. Needled yarn producing device equipped with perforated guiding bushes, which cooperate with the system of pricking needles, and with the system of receiving shafts, characterised in that it also contains an assembly of perforated bushes (T) that guide the band (T) of linearly formed fibres, which is beneficially slightly twisted, whereas the bushes are placed in supports (8) of the machine's frame (9), connected kinematically with the stepper motor (H), which change their position after each needling cycle, which cooperate with pricking needles (14) that are situated coaxially with holes or slots (I T) of the perforated bushing (T), on both sides of the bushing (T), whereas the pricking needles (14) are mounted into an arrangement of slidable needling beams (15) that cooperate with the sensor that is connected electrically with the stepper motor (13), placed in linear rolling guides QjT), seated upon two guiding pins (17), whereas the sliding needling beams (15) are connected kinematically with the electric driving motor (20), and the system of receiving shafts is also connected kinematically with the electrical driving motor (20).

2. Device according to claim 1, wherein it contains at least several perforated guiding bushes (T) that are situated one above the other or horizontally one beside the other, which are placed in common supports (8) and mutually connected with a toothed belt (12) or chain transmission or toothed wheels, and connected with a toothed belt or chain with the stepper motor (13), and each perforated guiding bushing (T) may consist of several parts that are mutually connected in series, whereas the longitudinal axial channel (10) of each guiding bushes assembly (T) is uniformly convergent into the travelling direction of the band (2) of needled linearly formed fibres, in such a way that hole in the longitudinal channel QO) at the inlet of the perforated guiding bushing (T) is bigger than the hole in the outlet channel (10) of the perforated guiding bushing (T).

3. Device according to claim 1 or 2, wherein each of the perforated guiding bushings (T) is more than 120 mm long, has a convergent internal longitudinal channel (10), where the diameter of its transverse section is more than 5 mm, and which has at least k = 4 rows of radial holes QA) with the diameter of at least 2 mm, at least five holes (JJJ in each row, made along the external surface of perforated guiding bushings (T) every 360/k°, or instead of holes has at least k = 4 slots that are made parallel to perforated bushing's axis.

4. Device according to claim 1 or 2 or 3, wherein each of the needling beams (15) is kinematically connected with the driving motor (20) by separate crank or cam mechanisms (19), whose rotational speeds are mutually synchronised.

5. Device according to claim 1 or 2 or 3 or 4, wherein the pricking needles (14) are conducted by crank or cam mechanisms (19), which are situated on both sides of perforated guiding bushings (T) and are at the same time sunk into lateral holes (11) of perforated guiding bushings (T) in the same planes that go through longitudinal symmetry axes of moving bands (2) of linearly formed fibres, which are processed into the needled yarn (5), whereas the pricking needles (14) are fed from each side into every second hole (I V) of the perforated guiding bushing (T), in such a way that only one pricking needle (14) finds itself at the opposite hole.

6. Method for obtaining the needled yarn by repeatedly and multi-directionally piercing the moving band of fibres that are formed in a linear way by pricking needles, wherein the band of fibres that are formed in a linear way, which is beneficially given a slight twist, moves inside the axial channel of the locating perforated guiding bushing (T), and is repeatedly pierced by pricking needles (14) that are situated perpendicular to the band of fibres that are formed in a linear way, and the multi- directivity is obtained through the band of linearly formed tentatively fibres is rotated axially in relation to the pricking needles distribution plane (14), after each needling operation, by an angle not lower than 30°.

7. Method according to claim 6, wherein as the band of linearly formed tentatively fibres is gradually moved into the outlet direction of the perforated guiding bushing (T), diameters of transverse sections of the channel of the perforated guiding bushing (T) are slightly and uniformly decreased into the travelling direction band of linearly formed and increasingly compacted fibres, thus increasing the impact of the internal surface of the wall of the axial channel (JO) of the perforated guiding bushing (T), and facilitating axial rotation of the needled yarn that is being formed, taking advantage of increasing friction between the needled yarn and the internal wall of the channel of the perforated guiding tube.

8. Method according to claim 6 or 7, wherein the needling operation of the band of linearly tentatively formed fibres is run backwardly, mechanically consolidating the moving band of loose linearly formed fibres from two opposite sides with pricking needles Q4) that pass one another, travelling at the same plane that goes through the longitudinal symmetry axis of the needled yarn that is being formed.

9. Method according to claim 6 or 7 or 8, wherein using round holes (11) in the bushings (7), first, while the needles (14) are outside the bushing (T), the band of fibres that are formed in a linear way is rotated together with the bushing (T), and then, while the band of fibres that are formed in a linear way and the bushings (T) are stationary, the needling operation is separately conducted on the band of fibres that are formed in a linear way, and in between these rotating and needling operations a fixed section of the needled yarn that has been produced is moved and collected using the stroke mechanism that is synchronised with the reciprocating motion of pricking needles and with the rotational motion of the band of fibres that are being formed in a linear way.

10. Method according to claim 6 or 7 or 8, wherein by using slots made parallel to bushing axis in perforated bushings (T), travel of the bundle of fibres being needled - and in the same way travel of the yarn - is continuous and has fixed constant speed.

Description:

Needled yarn producing device and a method of producing needled yarn

The subject of this invention is a needled yarn producing device and a method of producing needled yarn. More specifically, this invention refers to a device and a method of producing needled yarn out of a band of fibres that are formed in a linear way, designed for various technical applications.

Technical books describe a modernised flat needling machine, in which roving is needled in from ten to twenty parallel semi-grooves that occur in the machine's table. Description contained in the Polish patent application No. P-379900 describes a yarn- producing machine that contains a stationary perforated tube with holes on both sides, through which pricking needles are put inside. At the inlet of the perforated tube, there is a pair of shafts that feed the yarning tape into a longitudinal channel of the perforated tube, whereas at its outlet, there is a pair of receiving shafts that move the processed textile intermediate product along a row of pricking needles. Upper shafts of the feeding shafts pair and pairs of receiving shafts carry out an axially reciprocating motion caused by cams and cam followers, which cause rotational motion of the yarning fibre tape. Pricking needles are seated in needling plates that are fixed in beams, which carry out reciprocating motion caused by cam drive.

From the description contained in the Polish patent application No. P-379901, we know the way of producing yarn, which consists in that the fibres of the yarning tape, or several yarning tapes, or some other line intermediate product, are repeatedly and multi- directionally pierced by pricking needles that are used to produce unwoven fabrics, or by water jet with the pressure of approx. 150 atm., up till such time as the desirable compaction and proper tearing strength has been obtained.

Known needled yarn producing methods and known needled yarn producing machines have a number of disadvantages, which do not make it possible to obtain needled yarn with satisfactory quality parameters, such as: uniform distribution of needling operations, shape in the transverse section, uniform strength at a defined number of needling operations, transverse elasticity, and appropriate efficiency of the yarn producing

process with lowest needle brittleness possible. Because of that reason they were never deployed in the industry.

The aim of this invention is to deliver a solution that would provide a method of producing needled yarns, and for a device to produce such yarns simultaneously avoiding the technical problems known from the state of the art. What is unique for the device covered by this invention, which is equipped with rotational perforated guiding bushes that cooperate with a system of pricking needles with reciprocating motion and with a system of receiving shafts, is that it contains an assembly of perforated bushes that guide the band of fibres being formed in a linear way, whereas the band is caused to be slightly twisted, and the bushes that are placed rotationally in supports of the machine's frame are connected kinematically with the stepper motor, and change their position after each needling cycle, cooperate with pricking needles that are situated coaxially with lateral holes in perforated bushes, on both their sides, whereas the pricking needles are fixed to an assembly sliding needling beams, which cooperate with the sensor which is electrically connected with the stepper motor, while the beams are placed in linear rolling guides that are seated on two guiding pins. The needling beams are connected kinematically with the electric driving motor, and the system of receiving shafts is also connected kinematically with the electric driving motor. Bushing perforation can be made in the form of round or oval holes or slots that are parallel to bushing axis.

The subject of invention is a needled yarn producing device equipped with perforated guiding bushes, which cooperate with the system of pricking needles, and with the system of receiving shafts, characterised in that it also contains an assembly of perforated bushes (T) that guide the band (2) of linearly formed fibres, which is beneficially slightly twisted, whereas the bushes are placed in supports (8) of the machine's frame (9), connected kinematically with the stepper motor (13), which change their position after each needling cycle, which cooperate with pricking needles (14) that are situated coaxially with holes or slots (JJL) of the perforated bushing (7), on both sides of the bushing (T), whereas the pricking needles (H) are mounted into an arrangement of slidable needling beams QS) that cooperate with the sensor that is connected electrically with the stepper motor (JJ3), placed in linear rolling guides (18), seated upon two guiding pins (17), whereas the sliding needling beams (15) are connected kinematically with the electric driving motor (20), and the system of receiving shafts is also connected kinematically with the electrical driving motor (20).

Preferably, it contains at least several perforated guiding bushes (T) that are situated one above the other or horizontally one beside the other, which are placed in common supports (8) and mutually connected with a toothed belt (12) or chain transmission or toothed

wheels, and connected with a toothed belt or chain with the stepper motor (IT), and each perforated guiding bushing (T) may consist of several parts that are mutually connected in series, whereas the longitudinal axial channel (K)) of each guiding bushes assembly (T) is uniformly convergent into the travelling direction of the band (2) of needled linearly formed fibres, in such a way that hole in the longitudinal channel QO) at the inlet of the perforated guiding bushing (7) is bigger than the hole in the outlet channel (Kl) of the perforated guiding bushing (T).

Preferably, each of the perforated guiding bushings (T) is more than 120 mm long, has a convergent internal longitudinal channel QO), where the diameter of its transverse section is more than 5 mm, and which has at least k = 4 rows of radial holes (VV) with the diameter of at least 2 mm, at least five holes (I V) in each row, made along the external surface of perforated guiding bushings (T) every 360/k°, or instead of holes has at least k = 4 slots that are made parallel to perforated bushing's axis.

Preferably, each of the needling beams (15) is kinematically connected with the driving motor (20) by separate crank or cam mechanisms (19), whose rotational speeds are mutually synchronised.

Preferably, the pricking needles (14) are conducted by crank or cam mechanisms (19), which are situated on both sides of perforated guiding bushings (T) and are at the same time sunk into lateral holes Ql) of perforated guiding bushings (T) in the same planes that go through longitudinal symmetry axes of moving bands (2) of linearly formed fibres, which are processed into the needled yarn (5), whereas the pricking needles (14) are fed from each side into every second hole (I V) of the perforated guiding bushing (T), in such a way that only one pricking needle (14) finds itself at the opposite hole.

The next subject is a method for obtaining the needled yarn by repeatedly and multi- directionally piercing the moving band of fibres that are formed in a linear way by pricking needles, wherein the band of fibres that are formed in a linear way, which is beneficially given a slight twist, moves inside the axial channel of the locating perforated guiding bushing (T), and is repeatedly pierced by pricking needles (14) that are situated perpendicular to the band of fibres that are formed in a linear way, and the multi-directivity is obtained through the band of linearly formed tentatively fibres is rotated axially in relation to the pricking needles distribution plane (H), after each needling operation, by an angle not lower than 30°.

Preferably, as the band of linearly formed tentatively fibres is gradually moved into the outlet direction of the perforated guiding bushing (T), diameters of transverse sections of the channel of the perforated guiding bushing (T) are slightly and uniformly decreased into the travelling direction band of linearly formed and increasingly compacted fibres, thus

increasing the impact of the internal surface of the wall of the axial channel QO) of the perforated guiding bushing (T), and facilitating axial rotation of the needled yarn that is being formed, taking advantage of increasing friction between the needled yarn and the internal wall of the channel of the perforated guiding tube.

Preferably, the needling operation of the band of linearly tentatively formed fibres is run backwardly, mechanically consolidating the moving band of loose linearly formed fibres from two opposite sides with pricking needles (14) that pass one another, travelling at the same plane that goes through the longitudinal symmetry axis of the needled yarn that is being formed.

Preferably, using round holes (11) in the bushings (T), first, while the needles (14) are outside the bushing (T), the band of fibres that are formed in a linear way is rotated together with the bushing (T), and then, while the band of fibres that are formed in a linear way and the bushings (T) are stationary, the needling operation is separately conducted on the band of fibres that are formed in a linear way, and in between these rotating and needling operations a fixed section of the needled yarn that has been produced is moved and collected using the stroke mechanism that is synchronised with the reciprocating motion of pricking needles and with the rotational motion of the band of fibres that are being formed in a linear way.

Preferably, by using slots made parallel to bushing axis in perforated bushings (7), travel of the bundle of fibres being needled - and in the same way travel of the yarn - is continuous and has fixed constant speed.

The subject of this invention is shown in the example of a built device in the drawings, where: Fig. 1 illustrates schematically the way the needled yarn is produced, Fig. 2 illustrates a motion diagram of the pricking needles system in relation to the rotational motion of the perforated guiding bushing of the needled yarn producing device, Fig. 3 - perforated guiding bushing with round holes in overall view and axial section, Fig. 4 - perforated guiding bushing with slots in overall view and axial section, Fig. 5 - the setting of pricking needles sunk in the bushing with slots, while the yarn being formed is continuously travelling, Fig. 6 - the setting of the pricking needles in relation to the perforated bushing, Fig. 7 - view of the horizontal system of perforated guiding bushes and the assembly of pricking needles of the needled yarn producing machine, Fig. 8 - view of the vertical system of perforated guiding bushes, Fig. 9 - example of the module of upright bushes with stepper motor drive, Fig. 10 - module of the beam with bushes, Fig. 11 - module of needle beams drive.

By using a bushing with holes in the device, the needling process takes place in a periodical way, which results in the fact that adjustment of process parameters leads to

changes with limited stroke character. Stroke travel of the needled yarn coupled with stroke motion of receiving shafts makes it necessary to temporarily store in containers the yarn that has been produced.

In the second version of the invention, the needled yarn producing device is equipped with perforated bushes which guide the needled semi-finished product, while the bushes have perforation in the form of slots (Fig.4), and cooperate with the assembly of pricking needles with reciprocating motion, and with the assembly of receiving shafts that are operated continuously at a set rotational speed. Bushing perforation is made in the form of slots that are parallel to the bushing axis. The number of slots at bushing perimeter must be even, and the slots must be situated in pairs one against the other, so that pricking needles could freely come onto the other side of the bushing. By using slots needles can be deflected in an non-colliding way by the yarn, which is being continuously moved inside the bushing by receiving shafts (Fig.5).

Connected kinematically with the stepper motor, perforated bushes rotate around their axes together with the needled fibre band rotationally by an angle of (360/k°) or its multiple after each needling cycle, where k is a number of slots or a number of rows of holes at bushing perimeter. Bushes cooperate with the pricking needles, while the needles are situated perpendicular to bushing axis, and needle axes intercept bushing axis, whereas the pricking needles are mounted in the plates that carry out reciprocating motion into the direction perpendicular to axes of perforated bushes. The motion of plates with needles is coordinated with the motion of bushes by the control system that is made up of available subassemblies.

It is preferred that the needled yarn producing device has a modular structure, where a single module is equipped with several perforated bushes that are situated horizontally one beside the other (Fig.7) or in the vertical way one above the other (Fig.8), which are placed in their common supports and connected mutually by a toothed belt or chain or toothed wheels, and driven by a toothed belt or chain by the stepper motor. Each perforated bushing may consist of several parts, thus creating, depending on what is required, a subassembly of varying length in the module.

It is preferred when the perforated bushing's hole, through which the needled fibre is led, is slightly conical with convergence into the direction of motion of the needled half- finished product. In this way, the needled half-finished product is in contact with the wall of the hole at the whole length of the bushing, which facilitates rotation of the half-finished product together with the bushing in relation to the needles.

It is preferred that each of the perforated guiding bushes of the needled yarn producing device is more than 120 mm long, if its internal longitudinal channel is

convergent, if the internal diameter of its transverse section is more than 5 mm, and if it has at least k = 4 slots that are at least 3 mm wide or at least k = 4 rows of holes with diameter of at least 3 mm.

It is preferred that each of the plates with pricking needles of the needled yarn producing device is kinematically connected with the driving motor by separate crank or cam mechanisms, whose rotational speeds are mutually synchronised, so that when they are guided by crank or cam mechanisms that are situated on both sides of locating perforated guiding tubes, at the same time sink needles into lateral holes or slots of perforated guiding tubes, in the planes that pass through longitudinal symmetry axes of travelling fibre bands that are formed in a linear way, which are being processed into the needled yarn, whereas the pricking needles from each side are fed into every second hole of the perforated guiding tube in such a way that each hole holds only one pricking needle (Fig.6).

What is unique for the method of producing needled yarn by repeatedly and multi- directionally piercing with pricking needles the travelling band of fibres that are formed in a linear way, in line with this invention, is that the band of fibres that are formed in a linear way, which, beneficially, is slightly twisted, moves inside the axial channel of the perforated guiding bushing and is pierced repeatedly by pricking needles that are situated perpendicular to the band of fibres which are formed in a linear way, and by rotating perforated guiding bushing around its axis, the band of fibres that are formed in a linear way is rotated in relation to the pricking needles distribution plane, after each needling operation, by an angle not lower than 360/k°, whereas the rotation of the needled fibre band takes place as a result of friction forces between the band of fibres and the bush, and as a result of the rotational motion of the bush. It is preferred if, as the band of fibres that are formed in a linear way gradually moves into the outlet direction of the perforated guiding bushing, the diameter of transverse sections of the channel of the perforated guiding bushing decreases slightly and uniformly into the travelling direction of the band of fibres that are being linearly formed and are becoming more and more compacted, thus increasing the impact of the surface of the wall of the axial channel of the perforated guiding bushing upon the needled yarn that is formed, and facilitating rotation of the formed needled yarn with the bushing around its axis, by making use of the friction between the needled half-finished product and the wall of the channel of the perforated guiding bushing.

The subject of this invention" makes it possible to produce needled yarn out of the band of fibres that are formed in a linear way, slapping a lot of labour-consuming yarning process operations, whereas the needled yarn obtained in this method has its original

quality parameters that cannot be achieved using the classical method, and is fit to make technical products in various areas of application.

The subject of this invention is shown in the example of the built device in the drawings, where: Fig. 1 schematically illustrates the method of producing needled yarn, Fig. 2 - a motion diagram of the pricking needles system in relation to rotational movement of the perforated guiding bushing of the needled yarn producing device, Fig. 3 - the perforated guiding bushing with round holes in overall view and axial section, Fig. 4 - the perforated guiding bushing with slots in overall view and axial section, Fig. 5 - the setting of the sunk pricking needles in the bushing with slots, while the yarn being formed is continuously travelling, Fig. 6 - the setting of pricking needles in relation to the perforated bushing, Fig. 7 - view of the horizontal system of the perforated guiding bushes and of the assembly of pricking needles of the needled yarn producing device, Fig. 8 - view of the upright system of perforated guiding bushes, Fig. 9 - example of the module of upright bushes with stepper motor drive, Fig. 10 - module _ beams with bushes, Fig. 11 - module _ drive of needle beams.

In the example of the built device according to this invention, the needled yarn producing device has a modular design, and it consists, as in Fig.l, of the following assemblies: assembly 1 that guides and rotates the intermediate product 2 that is designed for the needling operation, needling assembly 3, assembly 4 that receives and stores the needled yarn 5 . that has been produced, elements 6 that synchronise particular assemblies' operations.

Assembly 1 (Fig. 9) that guides and rotates the roving 2, which is used as a intermediate product to produce the needled yarn 5, contains an assembly of four bushes 7, placed one above the other, which are situated in their common supports 8 of frame 9 of the device. Perforated bushes 7 are made up of two parts, which are coupled with each other by bushes. Each of the tubes 7 has a guiding channel U) (Fig. 3, Fig. 4) with convergence of 1 : 50 into the roving travelling direction 2, whose transverse sections become uniformly smaller as roving 2 consolidates more and more, and is transformed into the needled yarn 5_. Convergence of channel H) of the perforated tube 7 enables contact of the needled roving 2 with the surface of the guiding channel H) of the perforated bushing 7 at its whole perimeter and its whole length, despite roving 2 being compacted as a result of the needling operation. Each of the bushes 7 has six rows of holes ϋ, which are distributed at its perimeter every 60° (Fig.3), ten holes in each row, or six slots (Fig. 4). In order to obtain a desirable round shape of the transverse section of the needled yarn 5 as a result of the needling operation, cyclical rotation has been used of the perforated bushing 7 by an angle of 60° after each needling operation. An arrangement of four multi-part perforated

bushes 7 carries out the same process tasks and uses the same drive. Perforated bushes 7 are driven by the stepper motor 13 using the single toothed belt Vl- The whole constitutes a working module that is designed to be mounted in the needled yarn producing device.

The needling assembly 3 (Fig. 8) contains pricking needles IA that are placed in four rows 10 pieces each, one above the other, on both sides of the perforated bushing 7. Pricking needles 14 are fixed to needling beams 15, using intermediate plates 16, which are fastened to needling beams 15, by screws. The needling beam 15 is suspended upon two precisely made pins 17 and is placed in two linear rolling guides 18 (Fig.l 1). In the rolling guides IjI 1 the needling beam JL5_ moves with a reciprocating motion and is driven by the motorised speed reducer, whose speed is adjusted by an inverter through crankshaft and connecting-rod 19. Needling beams 15 move backwardly, in such a way that pricking needles 14 placed in two needling beams 15 mechanically consolidate roving 2 that finds itself within the perforated bushing 7 at the same time, at the same horizontal plane, and from two opposite sides. This leads to the machine's vibrations being significantly minimised. The whole assembly is mounted upon the machine's rigid frame 9.

The main drive of the needled yarn producing device is provided by its three-phase motor 20 with reducer (Fig. 11), which drives the needling beams 15, whereas the backup drive is provided by stepper motor 13, which rotates the perforated bushing 7. There occurs a dependence of the motion of the needling beams 15_ upon the motion of the stepper motor 13 that rotates the perforated bushes 7 each time precisely by an angle of 60°, while the crankshaft 19 (Fig. 11), during the return phase of the needling beams 15^ rotates by an angle of 80°, which is graphically depicted in Fig. 2. The three-phase motor 20 works in a continuous system, and its rotational speed is adjusted using the inverter. The stepper motor 13 works in strokes, and it is started up by signal from the induction sensor that cooperates with the needling beam 15, which, when finding itself in a strictly defined position, triggers the sensor's impulse.

The method of producing needled yarn in an exemplary application according to this invention consists in that the roving (half-finished product) moves inside the axial channel of the perforated bushing, and is repeatedly pierced by pricking needles, such as the ones that are used to produce unwoven needled fabrics. Pricking needles are maintained perpendicular to the roving, which rotates around its axis after each needling operation, changing its position together with the bushing in relation to the pricking needles distribution plane. This takes place as a result of abrasive impact of the surface of the wall of the axial channel of the perforated bushing, by uniformly decreasing the diameter of the transverse section of this channel into the roving travelling direction, in order to facilitate rotation of the roving together with the bushing in relation to the system

of needles moving in one plane which [i.e. bushing] goes through the symmetry axis of the roving. This leads to a needling operation on the spatially moving roving, thus providing for consolidation of the roving fibres as a result of the needling operation, as well as its high fluffiness desired, transverse elasticity, and proper mechanical strength. The needling operation is run from two opposite sides to mechanically consolidate the cyclically moving roving, using pricking needles that pass one another. First, the roving is rotated together with the bushing by the set 360/k around its own and the bushing's common axis, and then the pricking needles are sunk into the half-finished product and withdrawn. If the needling process is run using the bushing with round holes, then in between roving rotation and needling operation, an earlier set section of the needled yarn that has been produced is cyclically collected. In case a bushing with slots is used, yarn is collected continuously at speed rate as set for a given product assortment. Rotation of the half-finished product together with the bush, as well as the half-finished product needling operation, takes place at a set frequency.