CN106687628B

CN106687628B - Apparatus for producing core-spun yarn

Info

Publication number: CN106687628B
Application number: CN201580046194.1A
Authority: CN
Inventors: 汉斯·武尔施勒格; 克里斯汀·芬肯
Original assignee: AMSLER TEX AG
Current assignee: Amsler Co.,Ltd.
Priority date: 2014-08-28
Filing date: 2015-08-27
Publication date: 2020-02-21
Anticipated expiration: 2035-08-27
Also published as: WO2016030462A3; EP3186419A2; EP3186419B1; CN106687628A; WO2016030462A2

Abstract

The invention relates to a device (1) and a method for producing a core yarn (9) on a ring spinning machine. The apparatus (1) comprises: a first creel (10) intended to hold at least one roving bobbin (8); a second creel (12) intended to hold at least one spool of covering yarn (13); and a draft control device (15) adapted to adjust the draft of the covering yarn (13) before it enters the spinning process. Furthermore, the device (1) comprises a monitoring device (22) for monitoring the presence of the covering yarn (13) and, if no covering yarn (13) is present, for interrupting the supply of the roving (7) to the relative drafting unit (2). The covering yarn (13) is introduced into the spinning process by means of an injector (27).

Description

Apparatus for producing core-spun yarn

Technical Field

The invention relates to a device and a method for producing a core yarn (covered yarn) on a ring spinning frame.

Background

In the prior art, devices for producing core yarns on ring spinning machines are described. A core spun yarn was made as follows: the staple fiber sliver passes through a drawing unit in a ring spinning frame before being spun into yarn. With the addition of the second yarn, the second yarn will be at least partially wrapped around the staple fibers. Different locations for adding fibers are known.

US2013040523, nominally belonging to Japan Wool Textile co, ltd, was disclosed in 2 months in 2013. This application describes a heat and flame resistant protective garment fabric formed from spun yarns. The spun yarn used to form the fabric described above is a doubled yarn prepared by twisting a first yarn of the intimate blend spun yarn covered by a second yarn on a ring spinning frame.

DE19804341, nominally owned by the company Lida (Maschinenfabrik Rieter AG, Riter machinery) was published in 8 months 1999. The staple fiber sliver passes through a drawing unit, in which the fibers are extended, and then the fibers leave the drawing unit by passing between two delivery rolls (rollers) and are spun into a yarn. Additional yarn from a supply package (supply package) is added to the above process before the delivery rollers. The additional yarn passes between the transport rollers and is foreseen as wrapping the fibre.

WO9409195, nominally belonging to the Wool Research Organization of new zealand, was disclosed in month 4 of 1994 and this application describes a method and apparatus for producing a yarn comprising staple fibers twisted together with one or more filament or pre-staple yarns on a ring spinning frame or other type of spinning frame. A proportion of staple fibers is overfed into the structure to provide a lofty fibrous sheath that is hanked around a central core comprised of one or more filaments or pre-spun yarns and a second proportion of staple fibers.

DE102010051434, nominally belonging to Zwickauer Kamgenberg GmbH, is disclosed in 5 months 2012 and relates to a device comprising different fibre material templates provided for different fibre materials. A drawing roller for deforming (twisting) the fibrous material is provided. The fiber material separated from the pinch roller disposed at the downstream side of the draft roller is then twisted into a first yarn. The covering yarn is formed by supplying a fiber material from a fiber material supply unit to wrap the first yarn.

One disadvantage of the prior art is that the process of forming the core yarn is not adequately controlled, resulting in inconsistent results in terms of quality. Furthermore, the devices known from the prior art do not provide the opportunity to influence the process itself on a ring spinning frame with a plurality of spindles. Furthermore, the devices known from the prior art do not allow the spindles to be arranged in a dense manner.

It is therefore an object of the present invention to overcome the above problems known in the prior art.

Disclosure of Invention

The present invention relates to an apparatus and a method for producing core spun yarn based on a ring spinning frame. The apparatus can be used in a similar manner on any other type of textile machine, if appropriate. For each operating spindle (i.e. a spindle for producing a covering yarn (cladding yarn) can be foreseen according to the invention), the apparatus comprises a drafting unit having a plurality of drafting rollers rotating at different rotation speeds. The fibres of the roving (the sliver of unwound fibre) passing through the drafting unit are thus drawn in a defined manner, then spun into a yarn in a conventional manner by means of a traveler rotating around a spindle and wound onto a spool arranged on the relative spindle and rotating at a lower speed than the traveler. In the spinning triangle (the area in which the fibers exiting from the drafting unit are spun into a yarn), a covering yarn is added to the spinning process. In principle, the aim is to add core fibres such that in the resulting core yarn the core fibres wrap the yarn spun from the fibres of the roving.

The apparatus for producing core yarn on a ring spinning frame according to the invention comprises, for each operating spindle, a first creel intended to hold at least one roving bobbin and a second creel intended to hold at least one covering yarn bobbin. Furthermore, the device comprises a draft control device adapted to regulate the draw of the covering yarn removed from the covering yarn shaft and before the covering yarn enters the spinning process and correspondingly the core-covering process. The draft control device is preferably designed to regulate the draft of the covering yarn in a flexible manner. Furthermore, it is foreseen that the draft control device provides a force to unwind the covering yarn from its associated covering yarn shaft and/or to feed the covering yarn to a spinning process and, correspondingly, a covering process, where the covering yarn is wrapped around a spun yarn made of roving. If desired, a plurality of drafting control devices can be interconnected with one another, so that the drafting can be adjusted simultaneously on different operating spindles. In a preferred embodiment, the draft control device is designed to interrupt the feeding process of the covering yarn of each spindle individually, which may be advantageous, for example, in the case of maintenance. Furthermore, the device may comprise a monitoring device to monitor the presence of the covering yarn and, if no covering yarn is present, to interrupt the supply of roving to the relative drafting unit.

Preferably, in the spinning triangle of the spinning process of the roving, the covering yarn is fed by means of an injector into the spinning process and the corresponding covering process. In a preferred embodiment, the injectors are arranged adjustable with respect to the drafting unit of the relative spindle and the respective spinning point, in order to introduce the covering yarn precisely into the spinning process. Good results are achieved when the injectors are adjustable with respect to at least two axes spaced apart from each other. Depending on the design, the at least two axes are arranged at an angle with respect to each other or lie in a common plane.

When the second creel is arranged vertically above the first creel, a space-saving arrangement is obtained. Alternatively or additionally, the second creel may be integrally formed in the first creel.

In an embodiment of the draft control device, the covering yarn is clamped between at least one drive shaft and a pulley, as described by way of example below. If desired, there may be a pulley guide device which guides the pulley in the transverse direction. Alternatively or additionally, a pulley guide for lifting the pulley off the drive shaft can be foreseen, interrupting the influence of the drafting control unit on the covering yarn separately. Further details and variants of the draft control device are described below in connection with the figures.

In a variant, the draft control device comprises a first disc and a second disc arranged at a distance with respect to each other so as to form a peripheral channel through which the covering yarn passes to regulate the draft of the covering yarn.

Depending on the field of application, the monitoring device may comprise: a sensor for monitoring the presence of a wrap yarn; and an actuator for interrupting the supply of roving when the sensor indicates a fault condition of the covering yarn. In a low cost version, the monitoring device can be omitted, but in this case the weaving process is not automatically interrupted if a problem occurs with the covering yarn. In another variant, the monitoring device is integrated in the draft control device.

In a preferred embodiment of the monitoring device, the sensor comprises a deflection pulley driven by the covering yarn. The deflection pulley is interconnected with a transducer which provides a signal depending on the rotational speed of said deflection pulley and/or the tension in the covering yarn. The actuator comprises a receiver adapted to receive the signal of said transducer and to react to said signal, so that in case of a fault condition of the rotation speed of the deflection pulley and/or of the tension in the covering yarn, the supply of roving is interrupted by the actuator. The monitoring device may comprise an indicator which indicates a fault state of the relevant textile station optically and/or acoustically and/or via the bus. The actuator may comprise a blade or may be interconnected with a blade to interrupt the supply of the roving, for example by cutting the fibers of the roving.

In a preferred embodiment of the monitoring device, the actuator comprises or is interconnected with a wedge which is arranged in a displaceable manner and can be introduced in a defined manner between the entry rollers of the drafting unit. Thus, the supply of roving can be interrupted in a reliable manner. The wedge can be driven by at least one roller of the drafting unit or thus by the drive shaft. When the actuator becomes active, it receives a signal from the sensor of the monitoring unit, then the actuator releases the wedge, which then moves between the entry rollers based on the rotation of the entry rollers. Thus, the wedges temporarily lift the entry rollers apart from each other against the force of the springs. When the wedge reaches the final position, movement of the wedge is prevented by the block. Depending on the design, the wedge may be straight or curved, for example sitting on a drive shaft acting on at least one entry roller.

In a preferred variant, the draft control device is arranged vertically below the covering yarn spool. In order to increase the accuracy, a fiber guiding device can be arranged between the covering yarn spool and the draft control device to guide the covering yarn from the covering yarn spool to the draft control device in a precise manner. Alternatively or additionally, eyelets are arranged before the drafting control device for the covering yarn with respect to the direction of movement of the covering yarn, said eyelets influencing the interaction between the covering yarn and the drafting control device.

In a preferred embodiment, at least a part of the ejector responsible for delivering the covering yarn to the core-covering process is arranged to be movable (travelling/shuttling) in an oscillating manner with respect to the fiber movement in the transverse direction, i.e. parallel to the length direction of the textile machine. This can be achieved, for example, by arranging the entire injector, if present the monitoring device and other guiding means for the covering yarn, to run. In principle, the travel of the covering yarn in the transverse direction is synchronized with the movement of the roving with respect to the rollers of the drafting unit. Thus, extensive local wear of the rollers for the drafting unit can be avoided.

Depending on the field of application and the effect to be achieved, the rollers of the drafting unit may be operated at variable speeds, for example, the speed of the entry rollers suddenly increases and/or the speed of the delivery rollers suddenly decreases over a defined period of time, after which these two speeds are adjusted again to their normal values. Thus, the fiber supply of the roving is varied so that the yarn obtained comprises slubs associated with it, which are then cored by the covering yarn.

The method according to the invention comprises the following method steps:

a) providing a roving bobbin and a covering yarn bobbin;

b) providing roving from a roving bobbin to a drafting unit of a ring spinning apparatus, the drafting unit including a pair of entry rollers and a pair of delivery rollers;

c) drawing the roving in a defined manner between an entry roller of the drafting unit and a delivery roller;

d) spinning the fiber exiting from the drafting unit through the delivery roller into a yarn and winding the yarn onto a spool;

e) providing the covering yarn from the covering yarn spool to an ejector, the ejector introducing the covering yarn into the spinning process and a corresponding core-covering process in the region where the roving exits the drafting unit;

f) the draft in the covering yarn is regulated by a draft control device in the area between the covering yarn spool and the injector.

The presence of the covering yarn and, correspondingly, its condition is monitored, if necessary, by a sensor of the monitoring device. The sensor is interconnected with an actuator which will be used to interrupt the supply of roving when the sensor indicates a fault condition, i.e. when no covering yarn is present. Preferably, the sensor of the monitoring device is arranged between the injector and the covering yarn shaft and the actuator is arranged between the entry roller of the drafting unit and the roving bobbin.

Drawings

The invention described herein will be more fully understood from the detailed description given below and the accompanying drawings, which should not be taken to limit the invention described in the appended claims. The figures show:

FIG. 1 is a perspective view from above and to the left of an apparatus for producing core spun yarn;

fig. 2 is a perspective view of the device according to fig. 1 from above and from the right;

FIG. 3 detail E of FIG. 2;

FIG. 4 detail F of FIG. 3;

FIG. 5 is a front view of the apparatus according to FIG. 1;

FIG. 6 is a side view of the apparatus according to FIG. 1;

FIG. 7 is a partial view of the embodiment according to FIG. 1;

fig. 8 shows a monitoring device according to the invention.

Detailed Description

The foregoing summary, as well as the following detailed description of preferred embodiments, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there are shown in the drawings embodiments which are presently preferred, in which like numerals represent similar parts throughout the several views of the drawings, it being understood, however, that the invention is not limited to the specific methods and instrumentalities disclosed.

Fig. 1 shows a perspective view from above and to the left of an apparatus 1 for making a core spun yarn. Fig. 2 shows a perspective view of the device 1 according to fig. 1 from above and from the right. Fig. 3 shows detail E according to fig. 2. Fig. 4 shows detail F of fig. 3. Fig. 5 shows a front view of the device 1 according to fig. 1, and fig. 6 shows a side view. Fig. 7 shows part of the device in a simplified manner. Fig. 8 shows a monitoring device.

The illustrated apparatus 1 is incorporated in and correspondingly mounted on a ring spinning frame (not shown in detail) comprising a plurality of spindles arranged transversely to one another in the longitudinal direction of the ring spinning frame. In the drawings described herein, a ring spinning frame and its details are shown only as they relate to the description and understanding of the present invention.

For each spindle, the ring spinning frame includes a drafting unit 2 including a plurality of drafting rollers 3 rotating at different rotational speeds with respect to each other. The drafting unit 2 comprises a pair of entry rollers 4, at least a pair of intermediate rollers 5 and a pair of delivery rollers 6. A roving 7, consisting of parallel but unwoven fibers (not shown in detail), is unwound from a roving bobbin 8, passes through the drafting unit 2, after which it is subjected to the spinning process. As the rotational speed of the

rollers

5, 6, 7 increases in the direction of flow of the fibres of the roving 7 through the drafting unit, the fibres are drawn in a defined manner, after which they leave the drafting unit and are spun in a conventional manner into a yarn 8 by means of a traveller rotating on a ring around the spindle, and wound onto a spool arranged on the spindle and rotating at a lower speed than the traveller (not shown in detail). In the figures, the rovings 7 are shown by way of example as individual threads, although in practice the rovings 7 have a variable thickness over their length. Instead of the roving 7 which in principle consists of unwound fibres, yarns consisting of woven or partially woven elastic and/or inelastic fibres may alternatively or additionally be used.

For each spindle, the roving bobbin 8 is arranged vertically above the drafting unit mounted on the first creel 10 at a distance. From there the roving 7 is guided to a drafting unit where it enters the process described above.

Furthermore, for each spindle, the apparatus 1 comprises a covering yarn spool 11 arranged on the second creel 12. The second creel 12 may be attached to the first creel 10 or integrally formed therein, as appropriate. In an embodiment, the second creel 12 is arranged vertically above the first creel 10. The covering yarn 13 is unwound from the covering yarn spool 11 and guided by the guide device 14 to the drafting control device 15, which is normally arranged in the vertical direction above the drafting unit 2 but below the roving spool 8. The guiding device 14 of the variant of the invention shown here comprises a tube 14 which helps to guide the covering yarn from the covering yarn spool 11 to the drafting control device 15. It can be seen that the covering yarn 13 unwinds from the top of the covering yarn spool 11 and enters the air tube 14 at the upper end of the covering yarn spool 11. In the variant shown, the air tube 14 simultaneously acts as a holding device for the covering yarn spool 11. If appropriate, the air tube 14 can be at least temporarily filled with compressed air to transfer the loose end of the covering yarn 13 from the covering yarn spool 11 to the lower end of the air tube 14. This is particularly useful in preparing the weaving process.

In the variant shown, the draft control device 15 comprises at least one rotary drive shaft 16 which extends in the longitudinal direction (x-direction) of the spindle spinning frame and interacts with more than one spindle. The drive shaft 16 is mounted on a cantilever arm 17 attached to the frame of the spinning machine. Other ways of supporting the at least one drive shaft are also possible. Additional embodiments are described below. The drive shaft 16 is driven by an actuator (not visible) at an adjustable speed to adjust the tension in the covering yarn 13 and with respect to the production speed of the textile machine. During operation, the covering yarn 13 is clamped between at least one drive shaft 16 and a pulley 18, which is supported by the at least one drive shaft 16 and guided at least laterally by a pulley guide 19. In the variant shown, the pulley 18 is supported by two drive shafts 16 arranged parallel to each other and rotating at the same speed in principle. In order to avoid unnecessary travel of the covering yarn, a first eyelet 20 is arranged upstream of the drafting control device 15 to ensure that the covering yarn 13 is properly clamped between the pulley 18 and the at least one drive shaft 16. In order to interrupt the above process, the pulley guide 19 will act as or form part of a pulley lifting device as schematically shown in fig. 2. Thus, the pulley guide 19 is attached to the holding rod 21 in a swiveling (swill) manner so that the pulley 18 can be lifted from the drive shaft 16. This provides the following advantages: each spindle can individually interrupt the weaving process.

As in the embodiment shown herein, the draft control device 15 can be designed to be responsible for continuously and accurately feeding the cover yarn 13 to the spinning process and the corresponding core-covering process, in which the cover yarn is wrapped around the spun yarn 9. Thus, the draft control device 15 not only controls the draft in the covering yarn, but also provides the force for unwinding the covering yarn from the associated spool with the covering yarn and delivering the covering yarn 13 to the injector 27. The covering yarn 13 is sandwiched between at least one drive shaft 16 and a pulley 18. The force generated is at least partly responsible for pulling the covering yarn 13 away from the covering yarn spool 11 along the guide 14 (and across other guides, if present). However, the same force is responsible for preventing unnecessary slipping of the wrap yarn upstream or downstream. Fig. 4 shows in a schematic way how the covering yarn 13 is cladded around the spun fibres of the roving 7, forming a core yarn 9. In the variant shown, the covering takes place when the fibres of the roving 7 have been spun into a yarn.

Depending on the field of application, the drafting control device 15 may alternatively or additionally comprise two discs (not shown in detail) arranged parallel to each other at a distance, forming a peripheral channel. It is foreseen that the two discs clamp the covering yarn 13 between them in a defined manner. Each disk may include a slot arranged in a transverse direction and aligned with respect to the slot of the opposing disk. By adjusting the distance between the two discs, the resistance exerted on the covering yarn 13 can be adjusted. If desired, the disks may be actively driven by at least one drive shaft 16 as described above.

As can be seen for example in fig. 3 and shown in more detail in fig. 8, the covering yarn 13 interacts with a monitoring device 22 which interrupts the supply of the roving 7 when the supply of the covering yarn 13 is interrupted. In the variant shown, the monitoring device 22 is entirely mechanical and comprises a roll 23 mechanically interconnected with a blade 24 by a rod 25. The rod 25, the press roller 23 connected thereto and the blade 24 are rotatably attached to a holding frame 26. The presser roll 23, the rod 25 and the blades 24 interconnected therewith are movable between a closed position and an open position, whereby in the open position the roving 7 can pass freely through the monitoring device 22 and in the closed position the blades 24 are pressed against the holding frame 26 and thereby interrupt the supply of the roving 7 to the drafting unit. Good results can be achieved with a version adopted by the monitoring device as described in WO2010/006955 of the same applicant. Since the press roll 23 measures the tension in the covering yarn 13, it acts as a sensor. The blade 24 acts as an actuator, interconnected with the sensor via a rod 25. Thus, the actuator interrupts the supply of the roving 7 when the tension in the covering yarn drops below a defined level.

Alternatively or additionally, the blade 24 of the monitoring device 22 may be electromechanically controlled. Each monitoring device 22 therefore comprises a sensor which monitors the presence of the covering yarn 13 and, if not present or faulty, interrupts the supply of the roving 7 to the drafting unit 2.

Alternatively or additionally, the monitoring device 22 may comprise an indicator which indicates a fault state of the relevant textile station optically and/or acoustically and/or via the bus.

As can be seen in fig. 6, the draft control device 15 of the shown variant comprises a first and a second drive shaft 16 arranged parallel to each other in the longitudinal direction (x-direction) of the spindle spinning frame (not shown in detail) and rotating around their axis in the direction of arrow a. the first and second drive shafts 16, which are only partially shown in fig. 6, are supported by a cantilever 17 which is directly or indirectly attached to the spindle spinning frame (not shown in detail.) only half of the cantilever 17 is shown so that the inside becomes visible. it can be seen that each drive shaft 16 is supported inside the cantilever 17 by a first and a

second bearing

31, 32 having parallel axes of rotation but arranged at an angle α as shown in the figure. in the shown variant, the angle α is in the range of 125 ° to 175 ° and prevents the first and second drive shafts from jumping out of the bearing 31 in an undesired manner from the bearing 31. the first and second drive shafts 16 are provided by a section of segments assembled together by means of bushings 33 (i.e. interconnected with each other) and the drive shafts 16 are provided with a friction adjusting means such as a circumferential adjusting pulley 16 which is arranged to be located in an adjustable manner to be mutually connected to each other side of the outer surface of the spindle spinning frame 16, such as to provide a sliding between the outer surface of the pulley 16, such as a pulley 16, such as to be provided by a modular pulley 16, which is not to be connected to be easily movable, and to be connected to the pulley 16, such as a pulley 16, and to be connected to be easily to be able to be connected to be able to be connected to be easily to be connected to be a peripheral to be connected to be able to be a peripheral to be connected to be a peripheral to be.

Furthermore, as can be seen in fig. 1 to 3, each operating spindle, the device 1 comprises an ejector 27, which, in the illustrated variant of the invention, is arranged behind the delivery roller 6 of the drafting unit 2, in the direction of movement of the roving 7. As is clearly visible in fig. 3, the injector 27 comprises a first bucket (rail) 28 and a second bucket 29, which are arranged at a distance with respect to each other and are used to deliver the covering yarn 13 to the weaving process and the corresponding covering process. The first scoop 28 and the second scoop 29 are mounted to a holder 30, which in the embodiment shown is adjustable with respect to the position at which the covering yarn 13 is introduced into the weaving process. The holder 30 itself is mounted on an arm 37 which itself is rotatably arranged with respect to a mounting 38 interconnected with a fastening rod 39 which can be arranged in an oscillating manner in the x-direction together with the monitoring device 22 which in the shown variant is attached to the same fastening rod 39. In fig. 3, the oscillating movement of the injector 27 (here parallel to the x-direction) is schematically indicated by an arrow 40.

In the illustrated embodiment, the first scoop 28 and the second scoop 29 are arranged at an angle of approximately 90 ° with respect to each other. Other arrangements are possible if desired, as long as the introduction of the covering yarn 13 takes place at the correct position. The holder 30 shown in the embodiment is made of sheet metal. Alternatively or additionally, the retainer may be made of injection molded plastic and/or curved wire.

Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.

Name list

Apparatus for manufacturing core spun yarn

2 drafting unit

3 draft roller

4 enter the rod

5 intermediate roll

6 conveying roller

7 Rove

8 roving bobbin

9 yarn

10 first creel

11 wrap yarn shaft

12 second creel

13 wrap yarn

14 guide device, air tube

15 draft control device

16 drive shaft

17 cantilever arm (cantilever)

18 pulley

19 Pulley guide

20 holes

21 holding rod

22 monitoring device

23 pressure roller (monitoring equipment)

24 blade (monitoring equipment)

25 pole (monitoring equipment)

26 holding frame (monitoring equipment)

27 ejector

28 first scoop

29 second scoop

30 holder

31 first bearing

32 second bearing

33 bushing

34 bearing surface

35 outer surface of

36 running surface (Pulley 18)

37 arm

38 mounting member

39 fastening rod

40 oscillation (ejector)

Claims

1. An apparatus for producing a core spun yarn, the apparatus being adapted for use on a ring spinning frame and comprising:

a first creel (10) to be used for holding at least one bobbin (8) of rovings (7);

a second creel (12) to be used for holding at least one spool (11) of covering yarn (13);

a drafting unit (2) comprising a plurality of bobbins (3, 4, 5, 6), wherein the fibres of the roving (7) pass through the drafting unit;

-a drafting control device (15) adapted to adjust the drafting of the covering yarn (13) before it enters the spinning process;

an injector (27), the injector (27) being configured to introduce the covering yarn (13) into the spinning process such that the covering yarn (13) is wrapped around a yarn spun from the roving (7) in a spinning triangle in which fibers exiting from the drafting unit (2) are spun into a yarn.

2. The device according to claim 1, wherein a monitoring device (22) monitors the presence of the covering yarn (13) and, if it is not present, interrupts the supply of roving (7) to the drafting unit (2).

3. The apparatus according to claim 1, wherein the second creel (12) is arranged above the first creel (10).

4. The apparatus according to claim 1, wherein the second creel is integrated in the first creel (10).

5. The device according to any one of claims 1 to 4, wherein in the draft control device (15) the covering yarn (13) is clamped between at least one drive shaft (16) and a pulley (18).

6. Apparatus according to claim 5, wherein there is a pulley guide (19) guiding the pulley (18) in a lateral direction.

7. Apparatus according to claim 6, wherein the pulley guide means (19) is adapted to lift the pulley (18) away from the drive shaft (16).

8. The device according to claim 1, wherein the draft control device (15) comprises a first disc and a second disc arranged at a distance with respect to each other so as to form a peripheral channel through which the covering yarn (13) passes to adjust the draft of the covering yarn (13).

9. The device as claimed in claim 2, wherein the monitoring device (22) comprises: a sensor for monitoring the presence of the wrap yarn; and an actuator for interrupting the supply of roving (7) when the sensor indicates a fault condition of the covering yarn (13).

10. The apparatus of claim 9, wherein the sensor comprises a deflection pulley interconnected with a transducer, the transducer providing a signal as a function of a rotational speed of the deflection pulley, and the actuator comprises a receiver adapted to receive and react to the signal of the transducer, such that in a fault condition, the supply of the roving is interrupted by the actuator.

11. The apparatus of claim 9, wherein the actuator comprises or is interconnected with a blade (24) to interrupt the supply of the roving (7).

12. The device according to any one of claims 1-4, 8-11, wherein said draft control device (15) is arranged vertically below said spool (11) of covering yarn (13).

13. The device according to any of claims 1-4, 8-11, wherein a fiber guiding means is arranged between the covering yarn (13) spool (11) and the draft control device (15), guiding the covering yarn (13) from the covering yarn (13) spool (11) to the draft control device (15).

14. Device according to any one of claims 1-4, 8-11, wherein an eyelet (20) is arranged before the drafting control device (15) for the covering yarn (13) with respect to the direction of movement of the covering yarn (13).

15. The apparatus according to any of claims 1-4, 8-11, wherein the ejector (27) is arranged to oscillate with respect to the drafting unit (2).

16. The device according to claim 5, wherein the draft control device (15) comprises a first disc and a second disc arranged at a distance with respect to each other so as to form a peripheral channel through which the covering yarn (13) passes to adjust the draft of the covering yarn (13).

17. The apparatus of claim 10, wherein the actuator comprises or is interconnected with a blade (24) to interrupt the supply of the roving (7).

18. A method of making a core spun yarn, the method comprising the method steps of:

a. providing a bobbin (8) of roving (7) and a bobbin (11) of covering yarn (13);

b. supplying a roving yarn (7) from a bobbin (8) of the roving yarn (7) to a drafting unit (2) of a ring spinning device (1), the drafting unit (2) comprising a pair of entry rollers (4) and a pair of delivery rollers (6);

c. drawing the roving (7) in a defined manner between the entry roller (4) and the delivery roller (6) of the drafting unit (2);

d. spinning the fibers exiting from the drafting unit (2) through the delivery rollers (6) into a yarn (9) and winding the yarn (9) onto a spool;

e. -providing a covering yarn (13) from a bobbin (11) of said covering yarn (13) to an ejector (27) which introduces said covering yarn (13) into the spinning process in the region where the roving (7) exits the drafting unit (2);

f. -adjusting the draft of the covering yarn (13) by a draft control device (15) in the area between the bobbin (11) of the covering yarn (13) and the injector (27).

19. Method according to claim 18, wherein the presence of the core yarn is monitored by a sensor interconnected with an actuator, such that the supply of the roving (7) is interrupted by the actuator depending on the signal of the sensor.