Claims
- 1. Homogeneous splice for yarns having coupled wound tracts of single yarns having tail ends, said tracts of single yarns having in at least one tract of the splice, a number of twists which is less than the number of twists of the coupled yarn in the same tract, and a reciprocal centripetal thrust as between the two single yarns due to induced lengthwise shrinkage.
- 2. The homogeneous splice for yarns as in claim 1, wherein in at least one tract of the splice the single yarns have a band of support and mutual cooperation of a desired width.
- 3. The homogeneous splice for yarns as in claim 1 or 2, wherein at least one tract of the splice comprises coils of single yarns having a substantially constant slope.
- 4. The homogeneous splice for yarns as in claim 1 or 2, wherein at least one tract of the splice comprises coils of the single yarns having a variable slope.
- 5. The homogeneous splice for yarns as in claim 4, wherein the tract of the splice having coils with a variable slope is contained between a middle zone and an end zone of the splice.
- 6. The homogeneous splice as in claim 4, wherein the tract of the splice having coils with a variable slope comprises the whole splice.
- 7. The homogeneous splice for yarns as in claim 4, having a middle zone and two end zones wherein the tract of the splice having coils with a variable slope comprises at least part of the splice, and that the slope varies substantially similarly on either side of the middle zone of said splice.
- 8. The homogeneous splice for yarns as in claim 1, wherein the tail ends are free.
- 9. The homogeneous splice for yarns as in claim 1, wherein the tail ends are wound onto the single spliced yarn.
- 10. The homogeneous splice for yarns as in claim 1, wherein the tail ends are chopped.
- 11. The homogeneous splice for yarns as in claim 1, wherein the tail ends diminish in diameter toward the ends thereof.
- 12. The homogeneous splice for yarns as in claim 11, wherein the end part of the tail ends is wound in a position protected by a face of the single yarns.
- 13. The homogeneous splice for yarns as in claim 1, wherein the splice has an average intermediate diameter between 1.25 and 1.8 times the diameter of the single yarns.
- 14. The homogeneous splice for yarns as in claim 1, wherein the splice has a diameter in the zone where the tail ends are spliced varying from 0.8 to 1.25 times the diameter of the single yarns.
- 15. The homogeneous splice for yarns as in claim 1, wherein the splice has an average intermediate diameter between 1.05 and 1.25 times the diameter of the single yarns.
- 16. The homogeneous splice for yarns as in claim 1 having an average intermediate diameter between 0.8 and 1.10 times the diameter of the single yarns.
- 17. The homogeneous splice for yarns as in claim 1, including mainly free fly fibers protruding from at least the middle tract of the splice.
- 18. The homogeneous splice for yarns as in claim 1, including fly fibers positioned toward at least one end of the splice and anchored to the fibers of the single yarns.
Priority Claims (1)
| Number |
Date |
Country |
Kind |
| 83430 A/82 |
Aug 1982 |
ITX |
|
Parent Case Info
This is a division of application Ser. No. 439,320 filed Nov. 4,1982, now U.S. Pat. No. 4,720,966.
This invention relates to a new procedure for splicing yarns, whether textile or otherwise.
Joints made between textile yarns with fisherman's knots, weaver's knots or other kinds of knots are known.
Joints between yarns are also known which are made with adhesive or ties by winding yarn, outer silvers or fibers of the yarns themselves.
Joints are also known which are made by intertwining and entangling the fibers of the two yarns by blowing air or by means of electrostatic fields.
Joints made with these procedure entail drawbacks as regards the dynamometric properties, the ability to use the jointed yarn in usage devices downstream therefrom and the general properties of the joint.
Joints are also known which are made by untwisting the single yarns, uniting them and then twisting them together in the tract to be jointed.
The feature of the joints is coupling of two yarns and then twisting them together, having brought themm beforehand into a condition where the fibers are almost parallel before coupling them together.
These joints provide unsatisfactory mechanical properties since the fibers of the original yarns do not cooperate mutually except to a small extent and in an inadequate way.
This leads to unsatisfactory strength, inadequate ability to reproduce the joints, imperfect end zones, and an unsatisfactory strength of the joint in the long term.
Attempts have been made to improve the joints by opening out and ruffling the fibers when the latter are substantially parallel. This has been done by using mechanical and/or pneumatic means, but without obtaining results which are appreciable or of a satisfactory level.
Piecers working with a jet or jets of air, for instance, thicken the fibers by matting them and stiffening the jointed tract, with a resulting loss of elasticity and also consideralbe problems for the usage devices downstream therefrom, particularly as regards dyeing and warping operations and other later operations.
The present invention has an object to provide a splice between yarns, whether textile or otherwise, which not only has good aesthetics features but also possesses mechanical, technological and elastic properties, an ability to be reproduced and a life which have never before been attained.
Futhermore, the invention has as an object to provide splices which are not only homogeneous in themselves but are also suitable for meeting the needs of varied usage means downstream therefrom.
Indeed it is possible that the splices can be individually made suitable for the type of usage means downstream by comprising middle and transition lengthwise sections of a kind and form selected as wished.
It is also an object of the invention to provide a procedure suitable for making splices of the aforesaid type.
According to the invention two single yarns are untwisted until a negative twist is obtained in them equal to at least 15-20% of the initial positive twist, but the negative twist may even reach 100% or more of the initial positive twist (as an example, if the initial twist of the yarn is an S twist, the negative twist will be a Z twist).
The minimum negative twist, however, will depend on the properties of the yarn and on how the yarn reacts in a procedure according to the invention, and also on the length of the joint.
To make clear the procedure consider that the yarns initially have a Z twist.
After the untwisting operation both of the yarns have an S twist and the number of twists imparted per unit of length can be varied in relation to a plurality of factors as detailed earlier and as explained better hereinafter.
Next, the yarns are clamped in a coordinated manner and coupled together so as to be in mutual contact substantially, although not necessarily, along a generatrix in a tract of a set and suitable length.
The tract of length of mutual contact, however, will be related to the distribution of the lengths of the fibers and also the limit values of the length of the fibers.
As soon as the yarns have been coupled or else while the yarns are being coupled (in given conditions even before the coupling or during the retwist phase), the tail ends of the two yarns can be torn or plucked open or cut so as obtain small residual tails of the type and characteristics desired, perhaps even tapered progressively if such is wanted in relation to the properties of the final splice.
The cutting or plucking and/or tearing operations can also be performed before the coupling or at a time thereafter, for this is a phase of which the place in the procedure can vary in respect of the other phases without the results of the procedure being varied in most cases.
Steps are taken next to apply to the coupled yarns, in a tract approximately corresponding to that in which they are coupled, a retwisting action which tends to impart to the coupled yarns the same or more than the same twists (as regards quantity and direction) as were initially present in the single yarns.
This action of retwisting the coupled tract has the result that, starting from the time when the coupling takes place, the negative twist decreases in absolute value in the single yarns until an almost nil twist is obtained in them, that is, the fibers are positioned about parallel to the axis of the yarn.
As the retwisting action continue in the coupled tract, the retwisting action imparts to the simple yarns a positive twist which may be smaller or greater than or the same as the initial twist in the single yarn.
In the tract wherein the single yarns are coupled, which will be considered to be the tract that will constitute the splice, starting with the parallel coupled yarns one obtains instead a progressive twisting action until a number of positive twists about the same as the number of twists imparted to the single yarns have been applied to the coupled tract.
During this retwisting, as the number of twists imparted to the coupled tract progresses, and the therefore as the slope of the signal (reduction of the pitch) formed by the two single yarns increase, the yarns tend to shrink lengthwise while they are being wound around each other.
For the purposes of tensile strength this reciprocal winding acts in the same way as the slope of the fibers acts in a single yarn leaving the spinning process.
This means that, when the splice formed undergoes traction, the slope of the spiral generates a centripetal thrust that clamps the underlying layers by friction.
An improvement in the properties of the splice can be obtained by opposing the axial shrinkage of the coupling with a braking or clamping action applied to the ends of the splice during the twisting phase.
During the retwisting this action of opposition to the axial shrinkage is translated into a stess within the coupled yarns.
Owing to the slope of the winding spiral this stress produces a reciprocal thrust between the two single yarns along the coupling zone in question and therefore between the fibers in the two yarns cooperating in the zone.
As a result the fibers are more greatly forced to cooperate or else at least to place themselves in intimate union in the zone of mutual contact.
According to the invention this action of induced reciprocal thrust is especially increased in worth during the intermediate twisting phase when the fibers of each of the two yarns forming the coupling reach an almost nil value of twist or are substantially parallel to the axis of the respective single yarns.
When the value of the twist of the fibers of the single yarns is about nought, owing to the resulting softness of the single yarns the most favorable condition is obtained for an increase in the surface of contact between the two yarns, for reciprocal permanent deformation, for mutual adaptation and for possible cooperation.
In the position the fibers of the two yarns, which are substantially parallel to each other and at the same time are wound spirally, reach an intimate contact, a thing hard to obtain with such a high total of values by means of the procedures of the prior art.
Therefore, the negative twist imparted to the single yarns has substantially the effect, at the moment when the twisting produces the effect of mutual compression, of making the fibers of the single yarns substantially parallel and therefore suitable not only for becoming plastic and for interacting with each other but also for being permanently deformed and providing the maximum surface of contact between the two yarns.
Hence it can be deduced that the action of retwisting the coupled yarns causes lengthwise tension in the single yarns since a length becomes required which is greater than the length permitted by the axially stationary braking points as this lengthwise tension generates an induced reciprocal thrust.
We have spoken of "braking", but this lengthwise action in relation to the splice can also be an action of oppostion or of clamping which is and can be graduated as desired.
Hereinafter, therefore, by the words "braking" or "braked" we also mean all the alternative indicated and also others which can be inferred.
The value of the lengthwise tension can be graduated by utilizing axially stationary braking means of a yielding type having a known and desired yield and also by varying in a suitable way the braking thrust acting.
This makes it possible to intercept or graudate a take-up of yarn from outside the axial braking points or zones and also to have a consequentially graudated and selected axial feed of the coupled zone.
This also makes it possible to obtain fiber made more parallel and also an elastic elongation of the fibers, or not, of a desired value.
Hence it can be deduced that the value of the negative twist to be imparted to the yarns before they are coupled depends, amongst other things, on the length of the splice and on the properties of the fibers and, among these, their elongation property (field of elasticity and field of permanent strain).
Indeed, it is necessary that, during the forming of the splice, desired percentages of fibers should never be exceeded either as regards elongation in the field of elasticity, elongation in the field of permantent strain or the breakage limit.
After the phase of intimate cooperation with substantially parallel fibers, a further twisting up to the desired value improves the splice and has the effect of imparting a positive twist to the single yarns as well.
The procedure for splicing the yarns according to the invention may entail the employment of twisting means so as to obtain joints suited to a particular purpose.
If we consider a device with facing rings (but the device could use belts, rotating end rings, cones, sliding surfaces, etc.) the twisting means may be counter-rotating facing disks with a suitable coefficient of friction in relation to the yarns to be jointed.
For the sake of simplicity only circular rotating rings and other means cooperating therewith, always of a substantially circular type will be considered. But it is to be understood that all the other equivalent means too can be employed instead of the above and are therefore included.
The twisting means may comprise plain surfaces or specially worked surfaces.
This special working may be embodied with operating means having a desired form such as, for instance, a form with circumferentail sectors or a spiral or coil or others again, to suit the type of action (which may be tangential, tangential and axial, vibration, and so on) which it is wished to exert on the coupled zone.
The twisting means cooperate in pairs facing each other, and one of them advantageously rotates in the opposite direction to the other.
The twisting means may have the same or different diameters.
The twisting means may have the same kind of worked surfaces or different worked surfaces, or else one of them can be plain and the other can be worked.
The purpose of the specially worked operating means is to provide tangential and axial forces of desired value and direction during the retwisting phase.
Moreover, the twisting means serve to characterize the winding and to make it more uniform at the same time.
Furthermore, the twisting means serve to bring about compression forces which squash the fibers in the coupled zone and thicken them and reduce the diameter of the joint to the desired value.
The characterization of the winding permitted by the twisting means enables a desired winding slope of the coupled yarns to be obtained (slope of the winding spiral), so that the slope may be constant or variable or mixed, as desired and with the required properties.
The progression of the slope of the winding spiral starts at the middle of the splice and moves towards the edges thereof. This enables any requirements for an elasticity and/or strength differentiated from the middle to the periphery of the joint to be embodied to suit the needs of the usage means downstream.
A splice thus obtained according to the invention is already stable in itself, so that it is possible, as has been stated, to cut the tail ends of the yarns and leave a length thereof substantially free.
According to the invention, therefore, the action of cutting, plucking apart and/or tearing can be performed even when the splice has been made, and the tail ends thus remaining can be left free or be wound up with the means of the device or with other means envisaged for this purpose.
If it is wished to improve the splice, steps will be taken instead to perform cutting or plucking and/or tearing before the retwisting action makes the coupling too consistent.
The plucking and/or tearing action will find its own place, in respect of and in cooperation with the other phases, in relation to the length of tails ends which it is wished to obtain in proportion to the length of the zones spliced.
Thus, tail ends which are substantially short as compared to the length of the joint will permit a very broad working band within which the plucking and/or tearing phase can be fitted.
Long tail ends, which may reach a ratio of one to one in relation to the length of the joint, will only permit a very narrow working band since, the phase is substantially performed in cooperation with the transitory moment of having fibers parallel to the axis of the advantageously substantially straight yarn.
According to a variant of the invention, when the tail ends are long and tapered, it is possible to apply the negative twist to a tract upstream from the zone involved in the plucking apart and/or tearing action (or else to a part of the zone involved in the plucking apart and/or tearing action).
In this case, if the means placed towards the point of the tail end to prevent the application of the untwisting is loosened, when coupling takes place, the two tracts which have not received a negative twist but are coupled become affected by the extension of th untwisting or part thereof towards them.
According to the requirements of the usage means downstream it is possible for the ends zones of the tails remaining after elimination of the excess tail ends to cooperate with the facing twisting rings or with the mechanical equivalents thereof.
In that case one shall have the position that the end zone of the tail of a yarn will be wound more or less tightly onto the other yarn owing to the pulling effect of the twisting rings.
It is also possible that the end zone of the remaining tails has to be held within the facing twisting rings or their mechanical equivalents.
In that case the winding on the other yarn will follow the twisting and we one shall have a more or less tight splice depending on whether there are twisting means and in relation to the fact that the twisting means cooperate or otherwise in the zone or that at least one of the twisting means cooperates or not.
Where the twisting means cooperate with the zone of winding of the ends of the tails, the nature of the winding will depend on the conformation of the twisting means and on the configuration of the specially worked processing means.
The properties of the joint too will depend on the conformation and configuration of the twisting means.
In the case of certain usage means, when the single yarns are wound and have thier fibers substantially parallel with approxiately nil twists, it is possible to have a mechanical action of mutual penetration.
The mechanical action can be performed by processing with needles, pins, studs, etc, or with, or also with, jets of air.
The mechanical action may affect only the zone of the tails, or only the middle zone, or both of said zones according to an extent or lay-out desired.
The invention therefore embodies a splice between yarns, whether textile or otherwise, obtained by coupling single yarns by winding after the single yarns have been untwisted, the splice being characterized by comprising in at least one tract a number of twists in the coupled yarn which is about the same as the number of twists imparted to the single yarns after thay have been coupled whereby the single yarns comprise a negative twist greater than a nil value of twist at the time when they are coupled in a substantially parallel manner.
Moreover, the invention is realized with a procedure for the splicing of yarns, whether texile or otherwise, whereby the splice is obtained by coupling two single untwisted yarns and by re-applying twists thereafter, the procedure being characterized by the fact that the single yarns are untwisted beyond a substantially nil value of twist and are then coupled and retwisted until the single yarns have received a desired twist almost the same as the twists in the original yarn.
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Aug 1964 |
BEX |
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BEX |
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BEX |
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Divisions (1)
|
Number |
Date |
Country |
| Parent |
439320 |
Nov 1982 |
|
Patent Grant
4947635
