US3855772A

US3855772A - Method of and apparatus for producing yarn

Info

Publication number: US3855772A
Application number: US00392447A
Authority: US
Inventors: J Burlet
Original assignee: Institut Textile de France
Current assignee: Institut Textile de France
Priority date: 1972-09-01
Filing date: 1973-08-29
Publication date: 1974-12-24
Anticipated expiration: 1991-12-24
Also published as: ES418395A1; FR2198006B1; IT994716B; CH577040A5; GB1378610A; DE2343872A1; FR2198006A1; ES443506A1; BE804191A

Abstract

This invention relates to a method of and apparatus for producing yarn. In the present invention fibres are doffed from a combing device for supply to a yarn being produced in such a way that one end of the fibres is held until the fibre has been integrated into the yarn.

Description

ni W

3 atet [1 1 Burlet Dec. 24, 1974 [54] METHOD OF AND APPARATUS FOR [56] References Cited PRODUCING YARN UNITED STATES PATENTS [75] Inventor: Jean-Etienne Burlet, Roubaix, 3,254,482 6/1966 Stalego 57/5895 France 3,394,540 7/1968 Bentov 57/58.95

[73] Assignee: Centre Technique lndustrieldit:

lnstitut Textile De France, Boulogne Pr'mary Exammer john Petrakes sur Seine, France [57] ABSTRACT [22] Flled' 1973 This invention relates to a method of and apparatus [2]] Appl. No.: 392,447 for producing yam. In the present invention fibres are doffed from a combing device for supply to a yarn being produced in such a way that one end of the [30] Forelgn Apphcatmn Pnomy Data fibres is held until the fibre has been integrated into Sept. 1, 1972 France 72.31388 the yarn [52] US. Cl 57/58.95, 57/50, 57/156 [51] Int. Cl D01h 1/12 [58] Field of Search 57/50, 58.89-58.95, 16 Claims, 15 Drawing Figures The present invention relates to a method of and apparatus for spinning a yarn.

It is conventional to directly twist a roving or sliver of carded fibres with the aid of either a purely mechanical twisting device or of a pneumatic twisting device. In the case of an open-ended spinning method with mechanical twisting of the roving or sliver of carded fibres the yarn obtained has frequent irregularities and breaks since the yarn does not recover the fibres from the sliver either individually or in small groups but in parcels of figures. According to the open-ended spinning method which employs pneumatic twisting of the fibres, the fibres of the roving are pneumatically conveyed, virtually individually, into a tubular enclosure where the fibres are recovered by air turbulence intended to wind the fibres around the open end of the yarn. In view of the nature of the air turbulence it is almost impossible to direct the fluttering fibres singly to the open end of the yarn. On the contrary, the fluttering fibres are distributed quite haphazardly about the yarn and frequently accumulate in irregular knots.

In order to prevent the mechanical twisting device tearing from the sliver of carded fibres parcels of fibres, it has been proposed to eliminate the direct contact between the roving of fibres and the mechanical twisting device and to provide between the end of the sliver of fibres and the mechanical twisting device a zone for conveying, individualising and distributing the fibres, this zone consisting either of an electrostatic field or of a pneumatic transport tube which opens in the internal wall of an enclosure called turbine and rotating at high speed about its axis.

While in the case of the open-ended spinning employing an electrostatic field the fibres entering the device for twisting are parallel and thus lend themselves to the manufacture of a yarn which, with regard to tensile strength, is comparable to those obtained by the conventional ring spinning method, the spinning speed does not exceed that obtained with a ring spinning method. On the other hand, acceleration of the spinning speed beyond the conventional rates leads to defective yarns, because delivery of the individual fibres becomes uncontrollable at high spinning speeds. Moreover, this method can only be applied to fibres which are electrically non-conductive so that fibres which are non-conductive but moistened for example with a finishing medium cannot be spun by this method. A further disadvantage is that it is also necessary to employ an electric potential of several tens of thousands of volts.

Only the open-ended spinning method using a turbine has met with some industrial success. It must, however, be admitted that the fibres are less parallel than in yarns obtained by continuous ring spinning. In view of the special mode of distribution of the fibres by centrifugal force along the internal wall of the turbine and of the fact that the fibres fed into the said turbine tend to curl at their ends it is necessary to employ turbines of different diameters and suitable to each range of length of fibres if it is desired to prevent faulty yarns forming. In other words, fibres of substantially differing lengths cannot be spun simultaneously, nor in the same turbine, and a turbine of large diameter must be used for very long fibres. But it is not permissible to increase the diameter of the turbine beyond a certain limit which is a function of the maximum rotary velocity at which the said turbine is made to rotate and which generally is of the order of several tens of thousands r.p.m. Furthermore, the turbine method requires the use of dry fibres which prohibits utilisation of fibre treating products such as finishing agents.

According to one aspect of the present invention there is provided a method of spinning yarn in which a sliver of substantially parallel carded fibres are worked into a yarn being formed by twisting, such a method comprising transforming the sliver of fibres into a fringe of individual fibres or groups of fibres mechanically suspended by one of their ends, the free ends of the suspended fibres being progressively and successively supplied to the open end of the yarn being formed in a mannner such that a major portion of each fibre is substantially parallel to the yarn being formed in the region of the open end of the said yarn, and the said end of each fibre being held until the fibre has been intergrated into the yarn by the influence of the rotational effect imparted to the yarn by the twisting motion.

According to another aspect of the present invention there is provided apparatus for spinning a yarn, such apparatus comprising feed means including a rotary drum, a carding device for receiving a sliver of fibres from the fedd means, the carding device including a carding cylinder provided on its circumference with a plurality of carding pins, the carding cylinder being rotatable about an axis parallel to the axis of rotation of the said rotary drum, a rotatable combing disc for receiving a sliver of carded parallel fibres from the carding cylinder, the combing disc being rotatable about an axis perpendicular to the axis of rotation of the carding cylinder, the combing disc being provided on a peripheral surface with a plurality of radially arranged pins adapted to cooperate with the pins of the carding cylinder and being inclined relative to the axis of rotation of the combing disc to extend beyond the periphery of the combing disc for forming a fringe of yarn fibres mechanically secured by one of their ends to the said pins, doffing means for doffing the said fibres from the combing disc, and twisting means for twisting fibres doffed from the combing disc into a yarn.

In the present invention the combing disc no longer functions as twisting device and it can therefore be dimensioned sufficiently large to convey the fringe of fibres at a comparatively elevated peripheral speed while rotating at a low angular speed. On the other hand, the twisting device may be of very small diameter which enables it to reach extremely high rotary velocities, exceeding 100,000 r.p.m.

An illustrative embodiment of the invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is a schematic side elevation of one form of spinning apparatus,

FIG. 2 is a schematic plan view of the apparatus of FIG. 1,

FIG. 3 is a perspective schematic view of the carding cylinder, the combing disc and the doffing means,

FIG. 4 is a schematic elevational view of the elements shown in FIG. 3.

FIGS. 5 to 8 are schematic views of several successive vertical sections in the doffing zone of the combing disc,

FIG. 9 is a plan view on a larger scale of the doffing zone of the combing disc,

FIG. 10 shows schematically in vertical section the doffing zone equipped with a doffing means,

FIG. 11 is a schematic plan view of a number of spinning apparatuses mounted in parallel,

FIG. 12 is a schematic plan view of an entire bank of parallel arranged spinning apparatuses, and

FIG. 13 to 15 are respectively a front view, a plan view and a view in vertical section (along the line 0-0 of FIG. 14) of the combing circle equipped with a device having suction nozzles.

Referring now to FIGS. 1 and 2 there is shown spinning apparatus comprising a feed device 1, a carding device 2, a combing disc or circle 3, doffing means 4, a twisting device 5 and a yarn draw off device 6.

The feed device 1 is constituted, for example, by a trough and drum assembly the inlet opening la of which receives a wick or lap of fibres and the exit opening lb whereof opens onto a carding cylinder 2a of the carding device 2. The drum 1c of the feed device 1 and the carding cylinder 2a have parallel axes of rotation 1d and 2b and rotate in the same direction, for example in the clockwise direction as shown by the arrows F. Instead of a trough and drum assembly one can alternatively use pairs of drums or a small cylinder fitted with pins or with card clothing for conveying the lap of fibres toward the carding device 2. In that case this lap may undergo light drawing prior to entering into the feed device.

The roving or sliver of fibres which leaves via the opening lb of the feed device is combed by the sawtooth or pins 2c of the carding cylinder 2a the periphery of which moves in past the exit opening lb and which with its pins 20, in cooperation with a cylindrical surface 2d adjacent the opening lb entrains the fibres approximately individually and in the form of a roving or sliver of individual and substantially parallel fibres. The working width, i.e., the area over which the cylinder 2a is provided with pins can range from a few millimetres to several tens of millimetres (for example, 10 to millimetres) and is compatible with the wick or lap of fibres which has been fed in.

In the cylinder path of the pins 2c of the carding cylinder 2a. For example at the side symmetrically opposed to the outlet 1b relative to the axis, there is disposed the combing disc or circle 3 which comprises a circular table 3a rotatable in an anticlockwise direction F arranged in a plane parallel to that of the axes Id or 2b. The disc 3 is rotated by means of a shaft 3b extending perpendicular to the axes 1d and 2b. The shaft 3b is driven by a motor (not shown) through the intermediary of a belt and pulley transmission 30.

The rim 3d of the circular table 3a is provided with an array of pins 3c the individual pins 3f which extend radially outwardly and upwardly such that they are coincident with the generatrices of a cone, the apex of which is situated on the axis of rotation of the disc 3 and below the latter. In this way, the spacing between adjacent pins 3f at their bases is smaller than at their free ends. The spacing of the pins 3}" is similar to that of the pins of a conventional combing device and is, for example, determined by the number of pins per unit of length, this number preferably being comprised between five and pins per centimetre.

The outer diameter of the combing disc 3 is chosen so that an arc of a circle taken in the peripheral zone of the disc 3 and of a length equal to the working width of the carding cylinder 20 is approximately, a straight line. The combing disc 3 is arranged with respect to the carding cylinder 2a in such manner that the paths of the pins 2c of the carding cylinder 2a on the one hand and the paths of the pins 3f of the combing disc 3 on the other hand pass as close as possible to each other without the pins touching or intercalacting. It follows that the fibres of the roving or sliver of fibres supported by the tips of the pins 2c of the carding device 2 are removed from the latter by the pins 3f of the combing disc 3 and are retained at one of their ends on the lower portion of the array of pins 3e either by being pinched between two neighbouring pins 3f the lower ends of which are closer together than the free upper ends or by friction and/or partial winding of a fibre end around the lower portions of the pins 3f.

The roving or sliver of fibres as it is partially removed from the carding cylinder 2a, part of the fibres remaining hooked to the cylinder 2a, is converted to a fringe 3g of individual fibres 31' or at most small groups of fibres, the fibres 3i whereof are suspended by one of their ends at the lower portion of the pins 3f. The centrifugal force generated by the rotation of the combing disc 3 results in the fibres of the fibre fringe 3g hanging from the combing disc 3 at a certain inclination from the vertical, rather than vertically. Due to this centrifugal force the fibres are somewhat stretched and their free end is uncoiled so that they are approximately straight. This arrangement of the fibres of the fringe 3g under the influence of the centrifugal force is very advantageous for the presentation of these fibres in front of the open end of the nascent yarn, as will be described hereinafter. The centrifugal force acting on the fibres of the fringe 3g is, of course, insufficient to release them from their contact with the pins 3f of the combing disc 3 since the latter rotates relatively slowly.

To facilitate doffing of the individual fibres of the fringe 3;; from the combing disc there is provided diametrically opposite the carding device 2 the doffing means 4 which enable the fixed fibre ends of the fringe 3g to be progressively and successively released at the rate at which the free ends of these fibres are taken up by the open end 7a of the newly formed yarn 7.

In one form the doffing means 4 may comprise a stationary cam 4a disposed exteriorly of the combing disc 3 and along a portion of the circumference of the disc, which cam extends below and interiorly of the upper arm rim 3d of the circular table 30 and rises progressively to a land which is situated slightly below the free end of the pins 3f of the combing disc 3, while being parallel to and a small distance from the conical circumference or contour defined by the pins 3f. To facilitate the development of the cam 4a below and interiorly of the upper rim 3d of the circular table 3a the lateral surface 3k of the latter in frusto-conical and has a lower rim 3] the diameter of which is smaller than that of the upper rim 3d.

As is schematically shown in FIGS. 5 to 8 the captured ends of the fibres 3i climb progressively and successively toward the free end of the pins 3f under the influence of the cam 4a on the one hand and of the rotary movement of the combing disc 3 on the other hand, and when they arrive at the level of the horizontal land of the cam 4a the fibres 3i which are offered substantially parallel to the yarn 7 are recovered at their free ends by the yarn 7. In order to orient the fibres 31' parallel to the yarn 7 it is possible, in this event, to employ pneumatic means such as a low pressure compressed air issuing laterally of the cam 4a and directed parallel to the yarn 7.

When the fibre 3i is entrained in yarn it winds itself a few turns around the yarn 7 which rotates about its axis under the influence of the twisting device 5 since the other end of the fibre remains attached to the pin 3f for a brief moment before being pulled off the latter over the free end of the pin and the cam 4a (see FIG. 9), the degree of twist of the fibres 3i being less than 1 in the zone of doffing, i.e., of the open end 70 of the yarn 7.

It is also possible to use as doffing means an air nozzle 4b disposed interiorly of the array of pins 3e above the circular table and blowing in the doffing zone a jet of air upwardly toward the free ends of the pins 3f in such manner as to cause the captured ends of the fibres 31' to climb toward the free ends of the pins (FIG. 3). The air nozzle 412 may, of course, be employed in combination with a cam 4a. To adjust the position of the doffing zone it is necessary to adjust the flow of air, the angular and vertical position of the nozzle and the distance between the nozzle 4b and the pins 3f of the combing disc 3 (see arrows F and F FIG. 3).

On another form the doffing means may be in the form of a small smooth, serrated, or vaned, wheel 4c disposed above the combing disc 3, interiorly of the array of pins 3e and a few millimetres from the array of pins 3e of the doffing zone, in such manner that the axis of rotation 4d of the wheel is situated in a radial plane of the combing disc 3 and that the diameter of the wheel 40, taken in this radial plane, is at least approximately parallel to the pins 3f included in this radial plane. The diameter of this wheel 40 is of the same order of size of the working width of the carding cylinder 2a. The direction of rotation F of the wheel 40 is chosen such that the peripheral zone of the latter, which zone is situated near the circular table 30, rotates in a sense counter to that (F-, of the combing disc 3. In this manner an air current which causes the captured ends of the fibres 31' to climb towards the free ends of the pins 3f is created in the doffing zone, i.e., in the zone in which the open end 7a of the yarn 7 is located. The wheel 40 may also be used in combination with the cam 4a.

The newly formed yarn 7 around which the fibres from the fringe of fibres 3g are lightly wound by the action of rotation of the yarn 7 about its axis then passes into the mechanical twisting device 5 with the aid of which the fibres of the yarn 7 acquire their definitive Z or S twist between the end of the twisting device remote from the combing disc 3 and the yarn draw-off device 6. A false twist tube 5a for example, such as shown in the drawing and having a pointer bail 5b is utilised as a mechanical twisting device but it is possible to utilise other known false twist devices, for example those having pincers or lifting bars. It should be noted that the false twist tube 5a operates as a true twisting means and by virtue of its small radial dimension enables very high rotary speeds, which may exceed 300,000 r.p.m. to be attained. The tubular portion of the tube 5a is at its ends located in two bearings 5d, 5e and central portion of the tube 5a co-operates with a transmission belt 5f driven by a motor (not shown). It should be noted that the fibres 3i which cling to and wind around the yarn upstream of the twisting device 5 receive a provisional twist in a sense opposed to that of the definitive twist which is imparted to the yarn intermediate the exit of the twisting device 5, i.e., the pointer bail 5b, and the draw-off device 6. It is this provisional twist which enables a yarn to be obtained from the fringe of fibres. Moreover, the reversal of the twist direction of the fibres of the yarn 7 advantageously takes place within the tubular portion 5c of the twisting device 5 so that in this zone the fibres are guided in the axial direction of the yarn being formed. In this manner the weakest point of the yarn is well protected and the risks of the yarn rupturing are eliminated. The rotation of the yarn can also be brought about by an air turbulence obtained by tangentially blowing air in a tube which traverses the yarn.

The draw-off device 6 comprises for example two draw-off

rollers

6a, 6b which are applied against each other in an adjustable manner and at least one of which is driven at an adjustable rate by a motor (not shown). The yarn which leaves the draw-off device 6 constitutes the finished product 8 and is wound up on a bobbin (not shown) after first passing, optionally, over a return pulley 9.

The essence of the present method consists in realising a fringe of parallel fibres, offering the fibres of the fringe progressively and successively to the open end of the yarn, preferably in such manner that the fibres are substantially parallel to the yarn being formed in the zone of its open end, still lightly retaining one end of the fibres the other end of which lightly winds around the yarn being formed and releasing the retained fibre end when the fibre adheres sufficiently to the nascent yarn, and finally imparting a final twisting to the nascent yarn so as to obtain a finished yarn. By the expression nascent yarn" is to be understood a yarn-like assembly of fibres which are substantially parallel to one another and have a degree of very light winding about the axis of the yarn.

It will be readily understood that the speeds of rota tion of the various device 1 to 3 and 5 are adapted to one another in such manner that one first obtains a fringe of fibres and that the quantity of fibres necessary for formation of the yarn is then at any instant offered to the open end of the nascent yarn. The speed of the fibres of the fringe being presented varies of course as a function of the length of the fibres utilised and of the count of yarn to be obtained. As to the rate at which the yarn is drawn off and which is determined by the peripheral velocity of the draw-off rollers, this rate is, of course, controlled as a function of the degree of twist it is desired to impart to the yarn. Finallly, it is the speed of rotation of the twisting device which determines the production of the yarn. In a general manner, the peripheral velocity of the combing disc equals 0.5 to 2.5. times that of drawing the yarn off and all the other speeds such as those of feeding the lap of fibres and of rotation of the twisting device are adapted to the yarn draw-off rate which may reach and even exceed 500 metres per minute.

With a view to imparting a satisfactory spatial stability to the location of the open end (FIG. 4) of the nascent yarn it is advantageous to provide this location in an angular zone of the combing disc 3 which is comprised between 60 and in the direction of rotation F of this disc, from the medium plane of the carding device 2. Preferably the point where the fibres 3i are end there is illustrated in FIG. 11 preferred position of 5 the doffing means 4 relative to the circumference of the combing disc 3 and the carding device 2. When the median plane passing through the feed device 1, the carding device 2 and the axis of the shaft 3b of the combing disc 3 is designated by the reference xx'. The location of the doffing means which is in the form of a cam, for example, is situated to the left or right of the combing disc 3 and the plane x-x' according to whether it is desired to give the yarn a left-hand twist called S or a right-hand twist called Z while the combing disc rotates in anticlockwise sense [see arrow F (S)] or in clockwise sense [see arrow F (Z)]l, 2, 3 facing the arrival of the material to be spun. The disposition of the doffing means 4 in the first or second quarter, taken from the plane xx' and in the direction of rotation F-,(S) or F (Z) indicated in FIG. 11, of the circumference of the combing disc 3 has a beneficial effect on the rolling movement of the fibres 3i on the pins 3f and their detaching from the pins. Thus the tendency of the pins to carry the fibres beyond the central portion of the doffing means 4 formed by a cam 4a for example is reduced to a minimum or totally eliminated.

When the doffing means 4 are laterally and symmetrically positioned relative to the plane x-x, as is shown in FIG. 11, it is also desirable to choose the position of the twisting device 5 in such manner that the traction exerted on the nascent yarn 7 does not tend to lead back to the point where the fibres hooked to the pins 3f are being detached and toward the median plane xx of the apparatus. If b is the shortest distance between the detachment zone ZD on the doffing means 4 (or the cam 4a) and the median plane x-x, and if the distance between the axis of the twisting device 5 and the median plane x-x' is designated by d, then this tendency of the point of detachment of the fibres 31' to shift toward the median plane .r-x under the effect of the traction exerted on the nascent yarn 7 is eliminated when d at least equals b or preferably is greater than b.

It is obvious that in order to impart an S twist to the yarn the combing disc 3 is made to rotate in the direction of the arrow F (S) and doffing means 4 and the twisting device 5 disposed to the left of the plane x-x' at distances b and d will be utilised, the device 5 rotating in the sense of the arrow F ,(S), i.e., in anticlockwise sense, while in order to impart a Z twist to the yarn 7 one utilizes the doffing means 4 and the twisting device 5 disposed to the right of the median plane x-x', also at distances b and d with respect to the latter, the righthand combing disc 3 and twisting device 5 then rotating in the respective directions of arrows and Downstream of each twisting device 5 there is provided, as in the examples of FIGS. 1 and 2, a yarn drawoff device 6 comprising two partially overlying

rollers

6a, 6b.

In order to avoid repositioning the doffing means 4, the twisting device 5 and the draw-off device 6 every time the twist of the nascent yarn 7 is altered, it is advantageous to associate an assembly consisting of the feed device 1, the carding device 2 and the combing disc 3, which assembly is also called spinning head T,

with two series A and B respectively disposed at either side of the plane x-x', as shown in FIG. 11, and intended for either lefthand twist S or righthand twist Z and for discharge of the yarn 7.

In view of the fact that in large scale industrial applications of the invention one is not content with producing a single yarn but rather a plurality of yarns, it is advantageous to provide an apparatus comprising a bank of spinning heads T mounted in parallel, as is apparent from FIGS. 11 and 12. This arrangement enables the twisting devices 5 and draw-off devices 6 to be reduced in number by almost one half if all the yarns produced by this apparatus receive the same twist direction S or Z. In fact, in this case it suffices to provide at the distance d from the two median planes xx of two neighbouring spinning heads T (see FIG. 11) a single twisting device 5 and a single draw-off device 6 which, according to the twist direction of the yarn, will then then be associated with the spinning head situated to their right or that situated to their left, the distance d then being at least slightly larger than the radius R of the combing disc 3.

Such an arrangement is schematically illustrated in FIG. 12 where twisting devices I, to tn l are associated with spinning heads T, to T,,, thus only one unut more than the number of spinning heads T, to T,,. In other words, a twisting device t, to t,, is positioned downstream and in the extension of the zone between two neighbouring heads, for example T, and T at an equal distance d from the two neighbouring median planes x-x. An additional twisting device I, and 1 is also placed at the distance dfrom the median planes x-x' of the heads T, and T,, at each end of the apparatus.

There are thus it l twisting devices I, to t,,,, for n spinning heads T, to T,, but only n twisting devices are utilised for one or the other direction of twist applied to the yarn being formed, the last twisting device I, or t,,,, which is not utilised depending on the twist direction chosen.

In the case of the combined apparatus such as are shown in FIGS. 11 and 12 the feed devices 1, the carding devices 2, the combing discs 3, the twisting devices 5 or t, to t,,,, are driven by common shafts (devices 1 and 2) or belts (discs 3 and devices 5) from motors housed in the

lateral portions

10 and 11 of the frame of the said multiple installation, these

lateral portions

10 and 11 also containing the bearings for these common shafts.

In order to preclude any fouling of the combing discs by fibres remaining stuck to the pins after their passage in front of the doffing means 4, or more precisely after their passage in front of the detachment zone ZD of the nascent yarn 7, there is provided above the pins and close to the latter, downstream of the doffing means 4 taken in the rotary direction F (S) or F (Z) (see FIGS. 13 to 15) a suction nozzle, called service nozzle, B, or B situated upstream of the doffing means 4 associated with the opposite rotary direction F (Z) or F-,(S). This service suction nozzle B, or B is connected via a

tubing

13 or 14 provided with a gate V, or V for example eleetromagnetically, pneumatically or hydraulically controlled, to a general suction duct CA connecting the suction nozzles associated with the other combing discs 3 to a suction source such as the suction side of a blower. The gate V, or V, associated with the nozzle B, or B 2 opposite the detachment zone AD of the nascent yarn, for example the gate V, when the disc rotates in the direction 1 (5) and the yarn is formed from the zone ZD to the left of the combing disc 3, is continually open so that the corresponding nozzle E or B is continually in action and cleans the pins before they again pass in front of the carding device 2. The gate V or V, associated with the suction nozzle, called emergency nozzle, B or B situated in the immediate vicinity of the detachment zone ZD of the nascent yarn,

for example the nozzle B when the disc rotates according to arrow F (S), is generally closed, is associated with a conventional yarn break which controls the nascent yarn and acts on a mechanical, pneumatic or hydraulic electromagnetic relay of the said gate V in the sense that the latter opens and permits all the fibres to be suctioned off the combing disc 3 when the yarn has ruptured and the fibres are no longer accepted by the nascent yarn. Consequently it is no longer necessary to provide clutch devices for each rotating element of the various spinning heads so as to neutralise the effects of a possible yarn rupture. When the yarn has been knotted the relief nozzle (B is rendered inactive by closing the corresponding gate (V The present apparatus and method provide a number of advantages which may be listed as follows:

i. The possibility of processing fibres of very different lengths in the same apparatus,

ii. The possibility of processing conditioned fibres,

iii. The achievement of a very high yarn production rate with a twisting device of relatively small diameter,

iv. Manufacture of a yarn from a coarse sliver, and

v, Ease of effecting yarn knotting.

To these advantages of a general nature are added the special advantages for spinning of cardings, which advantages reside in:

i. Obtaining a yarn of traditional appearance,

ii. Elimination of the continuous unwincler at the card, and

iii. The possibility of producing a large bobbin without visible knots or tied ends.

We claim:

1. A method of spinning yarn in which a roving or sliver of substantially parallel carded fibres are worked into a yarn being formed by twisting, such a method comprising transforming the roving or sliver of fibres into a fringe of individual fibres or groups of fibres mechanically suspended by one of their ends, the free ends of the suspended fibres being progressively and successively supplied to the open end of the yarn being formed in a manner such that a major portion of each fibre is substantially parallel to the yarn being formed in the region of the open end of the said yarn, and the said end of each fibre being held until the fibre has been integrated into the yarn by the influence of the rotational effect imparted to the yarn by the twisting motion.

2. A method according to claim 1 in which each fibre is subjected to a centrifugal force during its supply to the yarn being formed.

3. A method according to claim 1 in which fibres being integrated into the yarn receive an initial twist in a direction opposite to the final twist of the yarn.

4. A method according to claim 3 in which the fibres are guided axially at the point where the twist is reversed.

5. Apparatus for spinning yarn, such apparatus comprising feed means, said feed means including a rotary drum, a carding device for receiving a roving or sliver of fibres from the feed means, the carding device including a carding cylinder provided on its circumference with a plurality of carding pins, the carding cylinder being rotatable about an axis parallel to the axis of rotation of the said rotary drum, a rotatable combing disc for receiving a roving or sliver of carded parallel fibres from the carding cylinder, the combing disc being rotatable about an axis perpendicular to the axis of rotation of the carding cylinder, the combing disc being provided on a peripheral surface with a plurality of radially arranged pins adapted to co-operate with the pins of the carding cylinder and being inclined relative to the axis of rotation of the combing disc to extend beyond the periphery of the combing disc for forming a fringe of yarn fibres mechanically secured by one of their ends to the said pins doffing means for doffing the said fibres from the combing disc, and twisting means for twisting fibres doffed from the combing device onto a yarn.

6. Apparatus according to claim 5 in which the diameter of the combing disc is such that an arc thereof equal to the working width of the carding cylinder approximates a straight line.

7. Apparatus according to claim 5 in which the combing disc is frusto-conical in cross-section.

8. Apparatus according to claim 5 in which the doffing means includes a stationary cam member, said cam member being arranged externally of the combing disc and extending from inwardly below the periphery of the disc to a position adjacent the free end of the pins of the combing disc.

9. Apparatus according to claim 5 in which the doffing means includes an air nozzle, the air nozzle being arranged above the combing disc and inwardly of the pins on the combing disc for directing a jet of air to ward the free ends of the pins.

10. Apparatus according to claim 5 in which the doffing means includes a'serrated wheel.

11. Apparatus according to claim 5 which includes a plurality of doffing means, said doffing means being arranged around the circumference of the combing disc in an angular zone located between 60 and l in the direction of rotation of the combing disc from the median plane passing through the carding means and the axis of rotation of the combing disc, the twisting means being located at a distance from the median plane which is equal to or greater than the distance between the said plane and the point of detachment of the fibres at the doffing means.

12. Apparatus according to claim 5 which includes a set of doffing means and twisting means for each direction of rotation of the combing disc, each set being arranged symmetrically relative to the median plane passing through the carding means and the axis of rotation of the combing disc.

13. Apparatus according to claim 5 which includes a plurality of spinning heads, each spinning head including a said feed means, a said carding device and a said combing disc, and a plurality of said twisting means, the number of twisting means being greater by one than the number of spinning heads, the twisting means being arranged so that there is an array comprising alternately a twisting means and a spinning head.

14. Apparatus according to claim 5 which includes a common drive arrangement for driving similar elements of each said spinning head.

nected via the conduit provided with the gate to a source of suction, and a yarn breaker the gate being 0perable in response to a command from the yarn breaker to operate the suction means.

Claims

9. Apparatus according to claim 5 in which the doffing means includes an air nozzle, the air nozzle being arranged above the combing disc and inwardly of the pins on the combing disc for directing a jet of air toward the free ends of the pins.

10. Apparatus according to claim 5 in which the doffing means includes a serrated wheel.

11. Apparatus according to claim 5 which includes a plurality of doffing means, said doffing means being arranged around the circumference of the combing disc in an angular zone located between 60* and 180* in the direction of rotation of the combing disc from the median plane passing through the carding means and the axis of rotation of the combing disc, the twisting means being located at a distance from the median plane which is equal to or greater than the distance between the said plane and the point of detachment of the fibres at the doffing means.

15. Apparatus according to claim 5 which includes a suction nozzle for removing fibres stuck to the combing disc.

16. Apparatus according to claim 5 which includes suction means associated with the combing disc, a conduit provided with a gate the suction means being connected via the conduit provided with the gate to a source of suction, and a yarn breaker the gate being operable in response to a command from the yarn breaker to operate the suction means.