Production of yarn

In order to produce core yarn wrapped with at least two separate wrapper yarns of the same or opposite hands, core material is passed in succession through a pair of rotary hollow spindles, each carrying a package of wrapper yarn whereby the core material is wrapped and which are relatively displaced so that the path of the material between a point just before the entrance of the first spindle and a point just after the exit of the second spindle deviates from a straight line so as to cause the core material or the resultant yarn to engage a rotary end of at least one of the spindles so as to apply false twist. The spindles may be supported so that their axes are displaced or displaceable in relation to one another for which purpose each spindle may be carried by a mounting capable of angular displacement about a support shaft and capable of being secured in any one of a range of angular positions. The apparatus may also include a take-up roller or rollers and a pair of intermediate rollers between the exit of the first spindle and the take-up roller or rollers.

The so-called process of wrap spinning involves passing a core of textile 
material through a hollow spindle which supports a package of wrapper 
yarn. The wrapper yarn is also passed through the spindle with the core so 
as to be withdrawn overend from the package and to be wound around the 
core in a helical path to bind the core together to form a coherent yarn, 
the pitch of the helices being controlled by the speed of the spindle. The 
core material may take various forms, but most commonly is constituted by 
a sliver delivered directly from a drawing head so that the fibres proceed 
directly from the delivery rollers of the head to the wrapping point. The 
binding material, referred to above as the wrapper yarn, need not strictly 
be a yarn at all and may comprise, for example, mono- or multi-filaments, 
natural or synthetic yarns, tapes, wires and so forth. In addition to the 
production of a straightforward core yarn, the same principle of operation 
can be used so as to give a slub or effect yarn by passing effect material 
along with the core material through the spindle, the effect material 
being overfed in relation to the core material. 
Wrap yarn produced in this way can be used for a variety of purposes and 
its characteristics can be varied as required. In particular, a wide 
selection of materials can be used for the core material and wrapper yarn 
and when an effect yarn is desired, even more variations are possible. 
Generally speaking, it is desirable to apply false twist to the core 
material so that the core is in a twisted state at the wrapping point. 
This false twist can be applied in a variety of ways, e.g. by a separate 
false twist device, by engagement of the core material with the rotary 
entry end of the spindle or by engagement with the rotary exit end of the 
spindle. When the overall strength of the yarn is a primary consideration, 
it may be necessary to apply more than one wrapper yarn by passing the 
core material in succession through two or more hollow spindles. If just 
two wrapper yarns are used, they may be wound with the same or opposite 
hands, the latter generally providing a somewhat greater strengthening 
effect. The present invention is concerned with yarns of this type, that 
is to say wrapped with at least two separate wrapper yarns of the same or 
opposite hands. 
According to the invention, such a yarn is produced by passing the core 
material in succession through a number of rotary hollow spindles, at 
least two of which each carry a package of wrapper yarn whereby the core 
material is wrapped, the path of the material between a point just before 
the entrance of the first spindle and the exit of the last spindle 
deviating from a straight line in such a way that the core material or the 
resultant yarn engages a rotary end of at least one of the spindles. Wrap 
spinning apparatus for this purposes comprises a number of hollow 
spindles, at least two of which are each constructed to carry a package of 
wrapper yarn and have a drive for rotating at least part of the spindle, 
the spindles being arranged in series so that core material or the 
resultant wrapping yarn can pass from the exit of one to the entrance of 
the next and the apparatus is so constructed that the path of core 
material between a point just before the entrance of the first spindle and 
the exit of the last spindle deviates from a straight line in such a way 
that the core material or the resultant yarn engages a rotary end of at 
least one of the spindles. 
The engagement of the core material or the resultant yarn with the rotary 
end of at least one of the spindles applies false twist which will extend 
to at least the first but usually to all of the wrapping points. Generally 
speaking, only two spindles carrying respective packages of wrapper yarn 
will be necessary, but one or more additional spindles may be included if 
required. Such additional spindles may each apply a further winding of 
wrapper yarn for further strengthening of the final product, but this may 
not be required and any additional spindle may serve merely for the 
application of false twist and may thus not carry a package of wrapper 
yarn. In addition to applying false twist itself, the presence of any 
additional spindle may cause the core material or yarn to be brought into 
engagement with the rotary end of one of the package-carrying spindles. 
Any additional spindle may be mounted either before or after the basic 
pair of package-carrying spindles, or it may be mounted between them. 
When using the basic arrangement of two spindles, the deviation of the path 
through them preferably results from relative displacement between them. 
This displacement may be either angular or transverse, that is to say the 
spindles may be supported so that their axes are displaced or displaceable 
in relation to one another. It is, however, also possible to obtain a 
devious path if the axes of the two spindles are in line and one or more 
control members are included between the adjacent ends of the spindles. 
When using spindles which are supported so that their axes are 
displaceable in relation to one another, adjustment of the relative 
displacement causes a corresponding adjustment of the degree of false 
twist applied and may also be used to control the number of points at 
which the core material or the resultant yarn engages a spindle or 
spindles. 
The relative displacement of the two spindles will normally be kept 
constant during operation, that is to say during the production of any 
particular package of yarn. Alternatively, however, the relative 
displacement of the spindles may be arranged to vary throughout the 
operation of the machine so as to produce a corresponding variation along 
the length of yarn in a package. 
In theory, a pair of fixed spindles may be used, but in practice it is 
usually necessary for the mounting of each spindle to be movable to allow 
for the doffing of an empty centre for a package of wrapper yarn and its 
replacement by a full package and the movement necessary for doffing may 
also provide the adjustment of the relative displacement between the two 
spindles. It will thus be understood that apparatus in accordance with the 
invention is capable of producing a wide variety of double-wrapped yarns 
which may or may not also include one or more effect components. 
After leaving the last of the spindles the resultant yarn is wound into a 
package which is normally preceded by a take-up roller or rollers. 
Generally speaking, these take-up rollers will run at substantially the 
same speed as delivery rollers preceding the arrangement of spindles and 
feeding core material to the entrance of the first spindle. In practice, 
the take-up rollers may need to have a slight lead over the delivery 
rollers so as to maintain a slight degree of tension in the core material 
and resultant yarn, thus avoiding any possible slack. If the take-up 
rollers are given a somewhat greater lead over the delivery rollers, the 
tension is increased accordingly and the characteristics of the resultant 
yarn are correspondingly affected. If the lead is increased still further, 
a degree of drafting of the core material or the yarn can be caused to 
occur and to prevent this being concentrated in the length prior to the 
first wrapping point, the delivery rollers need to be arranged close to 
the entrance to the first spindle, the shorter the fibre-length, the 
closer the spacing required. 
Under some circumstances, it may be desirable for the tension to differ 
between the first and the second or subsequent wrapping points. For this 
purpose an intermediate pair of rollers may be included between the first 
spindle and the take-up rollers and preferably between the two spindles if 
there are only two. By appropriate adjustment of the speeds of the 
delivery rollers, the intermediate rollers and the take-up rollers, a 
variety of different conditions can be obtained. In particular, the core 
material may be held under tension at the first wrapping point and may be 
relatively relaxed at the second or subsequent points, or the core 
material may be relatively relaxed at the first wrapping point and held 
under tension at the second or last wrapping point. 
Yet again, the difference in speed either between the delivery rollers and 
the intermediate rollers or between the intermediate rollers and the 
take-up rollers may be sufficiently great to cause drafting to occur. If 
drafting is required between the delivery rollers and the intermediate 
rollers, it is desirable, as with the example mentioned previously, that 
the delivery rollers should be arranged close to the entrance to the first 
spindle to ensure that the drafting does not all occur over the length 
prior to the first wrapping point. If the intermediate rollers are 
arranged between the last spindle and the take-up rollers, the drafting 
can take place without affecting the tension at any wrapping point. The 
different permutations and combinations of relaxation, tension and drawing 
over the respective reaches all give rise to different characteristics in 
the resultant yarn. 
If a second pair of intermediate rollers is included, drafting without 
affecting the tension at any wrapping point may be brought about between 
any pair of spindles. For example, two pairs of intermediate rollers may 
be included between the first and second spindles. By appropriate 
adjustment of the speed of the delivery rollers and take-up rollers, the 
first wrapping may occur under any required tension, drawing then occurs 
before passing to the second wrapping point and the second stage of 
wrapping occurs under any desired tension which is quite independent of 
that applied during drawing.

Turning first to FIG. 1, sliver 1 is shown entering a conductor 2 leading 
to the nip of a double apron draft-control arrangement indicated generally 
as 3, from where it passes to a pair of front drafting delivery rollers 4. 
From there, the sliver passes in succession through a pair of hollow 
rotary spindles 8 and 9, each of which carries a package of wrapper yarn, 
10 and 11 respectively. After leaving the spindle 11, the resultant 
wrapped yarn passes to take-up rollers 27 before being wound into a 
package. 
The spindle 8 is mounted on a bracket 14 which is pivoted about a support 
shaft 15 and can be secured in any one of a range of angular positions by 
means of a bolt 16 projecting through an arcuate slot 18 in a plate 17 
fixed to the bracket 14 and through a fixed plate 19. The bracket 14 is 
locked in any desired angular position by tightening a nut 20 on the bolt 
16 so as to lock the plate 17 to the fixed plate 19. Rotary drive to the 
shaft 8 is provided by a belt 21 in the usual way. 
The spindle 9 has a similar mounting including a bracket 14' pivoted on a 
support shaft 15' and is locked in any desired angular position by means 
of a nut 20' on a bolt 16' working in an arcuate slot 18' and passing 
through the same fixed plate 19. Rotary drive is provided by a belt 21'. 
The angular displacement between the axes of the two rotary spindles 8 and 
9 can be seen from the drawing and, as a result of this, the core material 
constituted by the sliver 1 engages the exit end of the spindle 8 at 25 
and the exit end of the spindle 9 at 26, from where it passes to the 
take-up rollers 27. The effect of the engagement with the rotary spindle 
at the points 25 and 26 applies false twist to the sliver 1 which extends 
back as far as the nip of the rollers 4 so that below these rollers the 
sliver 1 is shown in twisted form. The path of the sliver 1 and of the 
resultant yarn as just described is illustrated in diagrammatic form in 
FIG. 2, to which reference will now be made in order to describe the 
method of wrap spinning involved. This Figure includes a diagrammatic 
showing of the resultant yarn to an enlarged scale at two spaced regions 
following the respective wrapping points. The various parts are identified 
in FIG. 2 by the same reference numerals as in FIG. 1. 
Engagement of the sliver 1 at the point 25 produces false twist which, as 
previously described, will generally run back as far as the nip of the 
rollers 4. It is not essential that the false twist should extend back as 
far as this, but only that it should extend as far back as the point at 
which the core is wrapped by wrapper yarn from the package 10, this point 
being shown as 30. After passing the point 25, the sliver 1 enters the 
spindle 9 without engagement at the entry end and then engages the exit 
end of this spindle at 26 as previously described. 
In the particular example under consideration, the spindle 9 is rotating in 
the opposite direction from the spindle 8 so that wrapper yarn from the 
package 11 is wrapped with a reverse helix to that from the package 10, 
the actual wrapping point being indicated as 31. In the absence of the 
spindle 9, false twist applied at the point 25 would gradually disappear 
from the core material, but engagement at the point 26 with the oppositely 
rotating spindle 9 accelerates the disappearance of the false twist and, 
as a result, the sliver at the point 31 is somewhat more opened up than it 
would otherwise have been at the time of application of the second wrapper 
yarn. By individual adjustment of the angular positions of the two 
spindles 8 and 9, the degree of false twist applied at the points 25 and 
26 may be adjusted in relation to one another, thus providing relative 
adjustment of the degree of twist present at the two wrapping points 30 
and 31, thus making consequent minor adjustments in the characteristics of 
the resultant yarn. 
FIG. 3 illustrates the apparatus adjusted in such a way that there is no 
contact at all between the core material 1 and the upper spindle 8, but 
the core material engages the lower spindle 9 at its entry end as 
indicated at 35. 
The falst twist produced at this point runs back past both the lower 
wrapping point 31 and the upper wrapping point 30 and the degree of twist 
at these two points does not differ to any major extent. Consequently, 
both helices are wound on core material in much the same condition of 
twist and, as in the arrangement illustrated in FIG. 2, one helix will 
normally be the reverse of the other so as to give a cross-over helix. 
In the arrangement of FIG. 4, the upper spindle 8 is adjusted to the same 
general angular position as in FIGS. 1 and 2 so that there is engagement 
with the core material at the point 25. The lower spindle is adjusted to 
an angular position such that there is no contact at all with the core 
material and the construction of the lower spindle itself is modified, the 
spindle being fitted with a stationary inner sleeve 9A on which the 
spindle 9 runs on bearings 40. The presence of the stationary inner sleeve 
ensures that even if there is accidental contact between the core material 
and the sleeve at any point, the state of the false twist in the yarn will 
not be affected and furthermore the second wrapper yarn may pass freely 
around the core yarn since the core is in line with the axis of the second 
spindle and hence does not engage the spindle wall at the wrapping point. 
As illustrated, the wrapper yarn from the package 11 engages the edge of 
the stationary sleeve 9A and to avoid this, the sleeve may be made 
somewhat shorter than illustrated so that the engagement is between the 
wrapper yarn and the edge of the spindle 9 which is, of course, rotating 
at the same speed as the wrapper yarn itself. 
The arrangements so far referred to have illustrated the production of a 
straightforward core yarn. It will, of course, be understood that any of 
these arrangements may equally well be used for the production of an 
effect yarn merely by over-feeding effect material alongside the core 
material through the two spindles. FIG. 5 illustrates such an arrangement 
specifically, an additional pair of feed rollers being shown for 
overfeeding effect material 42 in a direction transverse to that of core 
material 1 so as to join the latter at a point shown as 43. The relative 
arrangement of the two spindles 8 and 9 is similar to that illustrated in 
FIG. 4 and engagement at the point 25 produces a false twist which runs 
back at least as far as the point 43 so that the over-fed effect material 
42 is wrapped around the core material 1 before reaching the first 
wrapping point 30. As in FIG. 2, there is a diagrammatic showing, to an 
enlarged scale, of the yarn at two regions following the wrapping points. 
A modification of this arrangement is that the wrapper yarn from the 
package 11 is caused to wrap the single wrapped yarn beyond the exit end 
of the spindle 9 at a point indicated as 33. As a consequence, the 
single-wrapped effect yarn from the upper spindle 8 passes generally along 
the axis of the spindle 9. There will be no significant engagement of the 
yarn with the inner surface of the spindle 9 other than that which might 
be caused by the protrusion of the effect component or by possible 
ballooning of the yarn as it passes through the spindle 9, but if this 
proves to be in any way disadvantageous, the spindle 9 may be fitted with 
a stationary inner sleeve 9A in the same way as illustrated in FIG. 4. 
In all the examples so far described, it has been assumed that the core 
material 1 is a sliver although, as explained originally, various other 
types of core material may be used if desired. The arrangement of FIG. 6 
may be of particular benefit for use with a core material 1 in the form of 
a rove and the angular position of the two spindles 8 and 9 is such that 
the yarn engages both the entry end of the spindle 8 at 34 and the exit 
end at 25 and also engages the exit end of the spindle 9 at 26. Effect 
material 42 is overfed by feed rollers 41 as in FIG. 5 and is wrapped at 
the point 30. A second effect material 45 is overfed by feed rollers 46 at 
a point between the two spindles 8 and 9 and is then wrapped at 31 so as 
to be combined with the single wrapped effect yarn emerging from the lower 
end of the spindle 8. 
The engagement at the upper end 34 and the lower end 25 of the spindle 8 
avoids the application of too severe a degree of friction to the core 
material thus avoiding risk of unduly upsetting or scuffing it in order to 
produce the necessary degree of false twist. Thus the engagement at the 
two points 34 and 25 means that the degree of deflection of the rove 
forming the core material 1 can be reduced, thus reducing the actual 
frictional contact with any one portion of the spindle. After wrapping 
with the second wrapper yarn at the point 31, the resultant yarn can 
withstand a greater degree of contact thus allowing the frictional contact 
at the point 26 at the exit of the spindle 9 to be increased. This will 
also mean that the wrapping configuration of the effect material 45 will 
differ from that of the effect material 42, this being shown 
diagrammatically at two spaced regions as in previous Figures. 
The modified apparatus of FIG. 7 includes an intermediate pair of rollers 
50 arranged between the spindles 8 and 9. Apart from this, the remainder 
of the apparatus is as shown in the first three Figures and the path of 
the core material and resultant yarn is as shown in FIG. 4. In other 
words, there is engagement with the rotary lower end 25 of the spindle 8, 
following which the yarn passes through the spindle 9 without any contact. 
The effect of the intermediate rollers 50 depends on their speed of 
rotation and, in particular, the relationship between the speed of these 
rollers and the delivery rollers 4 on the one hand and between the rollers 
50 and the take-up rollers 27 on the other hand. As explained earlier, in 
the absence of the rollers 50, the take-up rollers 27 are most usually 
given a slight lead over the delivery rollers 4 so as to keep the core 
material and resultant yarn taut during successive stages of wrapping. 
An increased lead increases the tension accordingly and may lead to 
drafting of the core material. The apparatus shown in FIGS. 1 to 6 is not 
designed for such drafting to occur, since generally speaking, the 
delivery rollers 4 are too far from the entrance of the spindle 8. In the 
apparatus of FIG. 7, however, it will be seen that the delivery rollers 4 
are mounted appreciably closer to the entrance to the spindle 8 so that if 
the rollers 50 are given sufficient lead over the rollers 4, drafting will 
take place in the region of the wrapping point 30. 
The main advantage of the inclusion of the rollers 50 is that the tension 
can be adjusted independently over the two reaches between the rollers 4 
and 50 and the rollers 50 and 27 respectively. In this way, the wrapping 
at one of the points 30 or 31 can be carried out under tension in the core 
material or yarn while that at the other can be carried out under relaxed 
conditions. Appropriate increase of the tension over either reach will 
lead to drafting. 
As an alternative to arranging the rollers 50 between the two spindles 8 
and 9, they can be arranged after the spindle 9 and before the rollers 27. 
With this arrangement, it is not possible to adjust the tension 
independently at the two wrapping points, but it is possible to draft the 
yarn after the completion of wrapping without affecting the wrapping 
operation in any way. If it is desired to carry out the drafting without 
affecting the wrapping action and while still allowing independent 
adjustment of the tension at the two wrapping points, it is necessary to 
fit two pairs of intermediate rollers between the spindles 8 and 9. 
Adjustment of the speed difference between the rollers 4 and the first 
pair of intermediate rollers 50 controls the tension at the first wrapping 
point 30, the yarn is then drafted between the two pairs of intermediate 
rollers and adjustment of the relative speeds of the second pair of 
intermediate rollers and of the take-up rollers 27 then controls the 
tension at the second wrapping point 31. 
From the examples just given, it is possible to appreciate the extreme 
versatility of the apparatus and the process involved. These examples 
represent only a relatively small proportion of the possible permutations, 
any of which can be used for the production either of a basic, 
double-wrapped core yarn or of a double-wrapped effect yarn. Not only can 
the appearance of the yarn be adjusted by selection of the number of 
contact points with the two spindles, but the degree of contact at any one 
of the points can also be adjusted by appropriate adjustment of the angle 
of the spindle in question. Further control is possible by adjustment of 
the tension at the respective wrapping points and by inclusion of a degree 
of drafting, if desired. 
Reference has already been made to the possibility of adjusting the axes of 
the two spindles in a transverse direction rather than angularly and it is 
also possible for the apparatus to be modified so as to allow for the 
possibility of adjustment in a generally axial direction so as to vary the 
spacing between the two spindles. For example, if the second wrapping 
point 33 is below the lower spindle 9, the adjacent ends of the two 
spindles may be virtually touching. As previously mentioned, the two 
spindles may rotate in opposite directions or in the same direction and a 
further variation may be achieved by adjusting the speeds of the spindles 
in relation to one another. Thus each spindle may rotate at a different 
fixed speed or the speed of one or both the spindles may be adjusted 
during the actual operation of the machine. Also as previously mentioned, 
one or more further spindles can also be included and may not necessarily 
carry any wrapper yarn. In addition to the false twist provided by 
engagement with one or more points on either or both spindles, a separate 
false twist device may be included if desired.