US3921268A

US3921268A - Device for the texturization of synthetic thermoplastic continuous fibers

Info

Publication number: US3921268A
Application number: US409594A
Authority: US
Inventors: Mario Caroglio
Original assignee: Montedison Fibre SpA
Current assignee: Montedison Fibre SpA
Priority date: 1972-10-27
Filing date: 1973-10-25
Publication date: 1975-11-25
Anticipated expiration: 1992-11-25
Also published as: JPS504352A; NL7314542A; LU68695A1; CH567588A5; BE806571A; ES419970A1; FR2204723B1; FR2204723A1; IT969996B; DE2353715A1; GB1444813A

Abstract

Apparatus is described for texturizing synthetic thermoplastic continuous filament yarns, consisting essentially of two hollow coaxial cylinders, one inside the other, of which the outer one is fixed and provided on its inside wall with a special guiding groove, while the inner cylinder is rotatable and provided on its outer wall, and parallel to its axis, with slots within which hooks are freely slideable, the base of the hooks fitting in the guiding groove of theouter cylinder, and whose motion depends on the configuration of said guiding groove. The guiding groove is in the form of two circular arcs perpendicular to the axis of the two cylinders, and located at different levels and communicating to each other by oblique connecting flutes. The base of the hooks is inserted into the guiding groove while the opposite yarnengaging end of the hooks is crooked or bent. The hooks are kept in the slots by both the inner wall of the fixed cylinder and a spring housed in an annular cavity around the outer wall of the inner cylinder.

Description

United States Patent [1 1 Caroglio [4 Nov. 25, 1975 DEVICE FOR THE TEXTURIZATION OF SYNTHETIC THERMOPLASTIC [73] Assignee: Montedison Fibre S.p.A., Milan,

Italy 22 Filed: Oct. 25, 1973 211 Appl. No.: 409,594

[30] Foreign Application Priority Data Oct. 27, 1972 Italy 31029/72 [52] US. Cl. 28/1.8 [51]. Int. Cl. D02G 1/14 [58] Field of Search 28/1.8, 72.15; 66/9 A, 66/57 [56] References Cited UNITED STATES PATENTS 1,443,999 2/1923 Merli et a1. 66/9 A 2,696,034 12/1954 Swartz 28/1.8 2,812,569 11/1957 Lawson et al.. 28/1.8 3,022,545 2/1962 Wylde 28/1.8 X 3,256,134 6/1966 Rice 28/l.8 X

3,335,475 8/1967 Hole 28/l.8 3,435,636 4/1969 Lindner et a1. 66/57 Primary Examinerl .ouis K. Rimrodt Attorney, Agent, or FirmStevens, Davis, Miller & Mosher [57] ABSTRACT Apparatus is described for texturizing synthetic thermoplastic continuous filament yarns, consisting essentially of two hollow coaxial cylinders, one inside the other, of which the outer one is fixed and provided on its inside wall with a special guiding groove, while the inner cylinder is rotatable and provided on its outer wall, and parallel to'its axis, with slots within which hooks are freely slideable, the base of the hooks fitting in the guiding groove of theouter cylinder, and whose motion depends on the configuration of said guiding groove. The guiding groove is in the form of two circular arcs perpendicular to the axis of the two cylinders, and located at different levels and communicating to each other by oblique connecting flutes. The base of the hooks is inserted into the guiding groove while the opposite yarn-engaging end of the hooks is crooked or bent. The hooks are kept in the slots by both the inner wall of the fixed cylinder and a spring housed in an annular cavity around the outer wall of the inner cylinder.

6 Claims, 4 Drawing Figures Nov. 25, 1975 Sheet 1 0f 2 US. Patent US. Patent Nov. 25, 1975 Sheet2of2 3,921,268

DEVICE FOR THE TEXTURIZATION OF SYNTHETIC THERMOPLASTIC CONTINUOUS FIBERS The present invention relates to a texturization device for thermoplastic continuous filament yarns and the relevant texturizing process.

More particularly, this invention relates to a device for imparting a regular wavy structure, essentially in one plane, to synthetic thermoplastic continuous filament yarns such as those based on polyamides, polyesters, etc.

Various crimping devices for continuous filament yarns have already been suggested in the prior art. These devices are based on thermal and mechanical treatments. The various prior art devices thus suggested differ from each other essentially in the way by which the crimping of the filament yarn is obtained. For this purpose various expendients have been suggested, such as that of passing the yarns between two rollers or gears, or between two series of thin blades, of which at least one is given an alternating motion, and interpenetrating each other so as to force the yarn to follow a winding path within the zone of multual interference where consequently the crimping takes place. These devices in practice, however, did not prove to be free of drawbacks, mainly due to their structural complexity and their complicated maintenance requirements. Moreover, with such devices satisfactory filament yarns are obtained only when operating at such low production rates as to be hardly remunerative, i.e. of little economical significance. In fact, the attempt to achieve high production rates with these prior art devices results in an inordinately high production of faulty filaments, due to the excessive number of broken fibers. 7

The texturization device which is the object of this invention, on the contrary, displays a great constructional simplicity and allows the high speed conversion of parallel continuous filament yarns made from synthetic polymers into yarns having a wavy structure essentially arranged within one plane, without giving rise to the previously mentioned drawbacks of the prior art devices.

The texturization device of the present invention consists essentially of two hollow coaxial cylinders, one inside the other. Of these, the outside cylinder is fixed and is provided with a special guide on its inside wall. The inner cylinder is movable and is provided on its outer wall, and parallel to its axis, with slots in which are disposed some freely moveable hooks whose base is inserted into the same special guide of the outer cylinder. That special guide may take the form of a groove shaped like two arcs of two circles which are perpendicular to the axis of the fixed outer cylinder, and which are arranged on different levels (i.e., displaced from each other along the axis of the fixed outer cylinder) and communicating with each other by two oblique connecting sections.

The dimensions of the hooks are appropriately correlated to those of the slots of the inner cylinder and to the size of the special, guide on. the inside wall of the outer cylinder. In fact, the hooks must be so constructed and arranged as to move freely with a rectilinear alternating motion inside the slots within which they are disposed and must slide freely along the special guide. Moreover, the length of the hooks is appropriately correlated to the difference in height between the two rectilinear sections of the special guide and to the length of the slots, in such fashion that when the base of the hooks is inserted in the lower part of the special guide (i.e., nearer the base of the fixed outer cylinder), they are disposed completely within the slots; while, when the base of the hooks is inserted in the upper part of the special guide (i.e., more removed from the base of the fixed outer cylinder), the curved upper part of the hooks projects completely outside the slots. Moreover, the hooks are curved or crooked at their upper ends so as to catch the yarn feed into and through the device. The yarn thus captured by the hooks is then dragged along by the hooks during their rectilinear retreating or reciprocating motion as the inner cylinder rotates. and thereby arranges itself between the crooked ends of the hooks and the projections of the slots of the inner cylinder, thus finally tak ing up the desired sinuous shape which is thereafter heat-set to produce the texturzized yarn product.

In this way one obtains a wavy or texturized yarn whose frequency of undulation depends on the number of hooks that operate per unit length on the outer circumference of the inner cylinder and whose wave height depends on the difference in height between the lower end of the stroke of the hooks and the upper zone of the projections of the slots.

According to another embodiment of the device which is the object of this invention, the special guide can be partially or completely movable. thereby permitting the curved upper part of all the hooks to project completely out of the slots so as to facilitate the threading operations of the yarn into and through the device when starting up.

The constructional and functional features of the yarn texturizing device which is the object of this invention will be even better understood through the following more detailed description taken with reference to the figures of the attached drawings which represent a preferred form of the device given merely for illustrative and not limiting purposes, and in which:

FIG. 1 represents a schematic view in axial cross section of the texturizing device;

FIG. 2 represents a schematic partial side view of the external surface of the inner cylinder of the device of FIG. 1;

FIG. 3 shows a schematic view of the inside cylinder of the device of FIG. 1, partially fluted; and

FIG. 4 represents schematically the application of the device of the preceding figures for texturizing a yarn made from synthetic thermoplastic continuous filaments.

The texturizing device under consideration consists of two hollow cylinders which are arranged coaxially with one inside the other. The outer hollow cylinder 1 is fixed and supports by means. of ball-bearings 3 a coaxial shaft 2 which is integral with the inner cylinder 4. The inner cylinder 4 is free to turn about its own longitudinal axis thanks to the motion imparted thereto through said shaft 2 by a suitable motor, not shown.

The fixed cylinder 1 is provided on its inner wall. and perpendicularly to its axis or generating lines, with a guiding groove 5. The guiding. groove 5 is formed by two arcs of circle DC and BA which are orthogonal to the axis or generating lines of the cylinder and which merge with each other through two oblique connecting flutes AD and CB.

On the outer wall of the inner cylinder 4, slots 7 are provided. These extend in a direction parallel to the axis of the inner cylinder (see FIG. 3). Within these slots 7 are hooks 6 freely slidable therein. The slots 7 define projections 9 (see FIG. 3) which at their upper ends are shaped in relation to the form that one wishes to impart to the undulations of the yarn filaments. A complementarily shaped base or extension 63 of each hook 6 fits into the groove of the outer cylinder 1 while the opposite end 6A of each hook is crooked or bent.

As they ride in the guiding groove 5 when the inner cylinder 4 is revolving, the bases 6B impart to the hooks 6 an alternating rectilinear or reciprocating motion in the slots 7 in a direction parallel to the cylinder axis, in coincidence with the two oblique connecting sections AD and CB. The amplitude of the reciprocating motion of the hooks corresponds to the distance by which the arcs AB and DC defining (with the connecting sections AD and CB) the guiding groove 5 are separated along the inner wall of the outer fixed cylinder 1.

The hooks 6 are maintained in position in the slots 7 by both the inner wall of the outer fixed cylinder 1 and a spring 8 housed in an annular cavity 10 extending circumferentially around the outer wall of the inner cylinder 4. For the sake of simplicity, the annular cavity 10 is shown in FIG. 1 but not in FIG. 3.

The dimensions of the hooks 6, of the guiding groove 5, and of the slots 7 are such as to allow the free alternating or reciprocating movement of the hooks inside said slots as well as the sliding of the base 6B of hooks 6 inside said guiding groove 5, though without too pronounced clearances.

Moreover, the length of the hooks 6 is conditioned by the difference in height between the two sections DC and BA of the guiding groove 5 and by the length of the slots 7, in the following way: When. upon the rotation of the inner cylinder 4, base 6B of the hooks 6 is inserted in the lower part of the guiding groove 5, that is, in the section DC, the hooks 6 must be completely immersed in the slots 7 of cylinder 4 for a depth that will depend on the height of the wave one wishes to impart to the undulation of the yarn undergoing processing. When the base 68 of the hooks 6, on the contrary, is inserted in the upper part of the guiding groove 5, that is, in section BA, then the crooked or curved end 6A of the hooks 6 must project completely beyond or outside the slots 7.

FIG. 1 illustrates the various positions that the hooks 6 take up during the rotation of the inner cylinder 4. Thus, more particularly. 6.\' represents the position of a hook 6 when its base is positioned in section DC of the guiding groove 5; 6y shows its position when its base is positioned in section BA; while 6: shows its position when its base is positioned in the oblique connecting sections AD and CB.

In practice, operation of the above described texturizing device is as follows:

Once all of the hooks 6 are arranged in the slots 7 with their bases 68 inserted in the guiding groove 5, the inner cylinder 4 is made to revolve, for instance in a clockwise direction, and the continuous filament yarn to be texturized is simultaneously fed to the device. Upon reaching point B of guiding groove 5, the hooks 6 take up, as explained previously, the position of full projection of their crooked or curved ends 6A from slots 7 as shown at 6y.

The yarn to be texturized, after a preliminary heating, is fed by known guiding means into the space between the crooked or curved end 6A and the upper end of the corresponding projections 9 of the slots 7. The positioning of the yarn in this manner between said ends occurs while the hooks 6 are in the section BA. Subsequently, during the transfer of the hooks 6 from point A to point D of the guiding groove 5, the yarn is caught by the crooked or curved ends 6A and pulled downwardly. thereby assuming a wavy configuration 11a as shown in FIG. 2, between the ends 6A and the projections 9.

This wavy configuration 11a is maintained over the whole are of circle of the guiding groove 5 between D and C, where in the first section thereof the individual filaments suffer dissymmetries in their inside structure; dissymmetries which are set in the filaments in the second part of the arc of circle D-C by means ofa cooling achieved either by the convective movements of the surrounding air or by a forced blowing in of air or other like fluids through the region of yarn travel in the texturizing device.

In oblique section CB, the hooks 6 gradually rise to the position shown at 6 thereby releasing the undulated filament which is then conveyed by a suitable thread guide towards a yarn take-up device in conventional manner.

As already mentioned, the yarn to be texturized, before being fed into the texturizing device of the present invention, is heated up to a suitable temperature. This temperature, which in general must be lower than the softening point of the polymer of which 'the yarn is composed, depends on various factors such as the advancing speed of the yarn, on its count, on the type of polymer that forms the fiber, etc. Thus, for instance, in the case of a polyhexamethylendiamine adipate (nylon 6. 6) yarn or of a polyethyleneterephthalate yarn, the temperature is between and 240C.

The heating step is carried out by passing the yarn over a metal plate which is heated electrically or by hot fluids, or by any other equivalent heating means well known in the art.

FIG. 4 shows the position and arrangement of the texturizing device of the present invention when inserted in a drawing line for as-spun yarns in a regular plant operation. As can be seen from the figure, the totality of undrawn filaments 11, coming directly from a spinneret or from a spin-cake (not shown), is passed through a feed-roller 12 which is provided with an idle roller 13 for separating (spacing) the coils of filaments. It is then passed over draw pin 14 made of sintered ceramic material and is then taken up by a stretch-roller 15 which also is provided with an idle roller 16, and which is revolving at a peripheral speed greater than that of roller 12. The totality of drawn filaments thus obtained is then heated by passing over an electrically heated metal plate 17, whereafter the filaments are subjected to crimping in the crimping device 18 of this invention as shown in FIGS. l-3.

As previously indicated,.the undulation imparted to the yarn depends on the constructional characteristics of the device of this invention. More particularly:

a. the frequency of undulation depends on the number of hooks 6 that are operating per length unit on the outer circumference of the inner rotating cylinder 4;

b. the wave height depends on the magnitude of the stroke of the hooks 6 below the upper or outer zone of the projections 9; and

c. the shape of the wave depends on the form of the cross-section of the hooks 6 and of the projections 9 in the zones of contact with the yarn.

The device of this invention allows one to easily vary the above-indicated crimping characteristics by simply replacing parts of the device itself.

Moreover. since the forces to which the hooks 6 are subjected during the processing are directed chiefly along the longitudinal axis of the hooks, the device in question is characterized by an uncommonly high resistance to the stresses imparted by the moving yarn. Similar considerations apply with regard to projections 9 which, being integral for their full length with the outer wall of the inner rotating cylinder 4, are capable of offering the maximum of resistance, without any deformation, to the stresses imparted by the moving yarn.

From the foregoing description, it is quite evident how versatile is the crimping device of the present invention with regard to the range of counts of the workable filaments, the simplicity of construction of the moving parts, their sturdiness and their high working speed, all contributing to significant advantages in commercial operation.

What is claimed is:

1. Apparatus for texturizing synthetic thermoplastic continuous filament yarns, consisting essentially of two hollow coaxial cylinders, one inside the other, of which the outer one is fixed and provided on its inside wall with an internal guiding groove, while the inner cylinder is rotatable and provided on its outer wall, and parallel to its axis, with slots within each of which an element ending in a yarn-engaging hook is freely slideable, the base of each element fitting in the internal guiding groove of the fixed outer cylinder, and whose motion depends on the configuration of the guiding groove, the guiding groove on the fixed outer cylinder being in the form of two circular arcs perpendicular to the axis of the two cylinders, and located at different levels and communicating with each other by oblique connecting flutes.

2. Texturizing apparatus according to claim 1, wherein the base of the hooks is inserted into the guiding groove while the opposite end of the hooks is crooked or bent.

3. Texturizing apparatus according to claim 1, wherein the length of the hooks is correlated to the difference in level between the two rectilinear sections of the guiding groove and to the length of the slots. such that when the base of the hooks is inserted in the lower part of the guiding groove the hooks are positioned completely within the slots of the rotatable inner cylinder, for a depth which depends on the desired wave height, and when the base is inserted in the upper part of the guiding groove the crooked ends of the hooks project completely out of the slot.

4. Texturizing apparatus according to claim 1, wherein the fixed outer cylinder supports on ball-bearings a coaxial shaft integral with the rotatable inner cylinder, said shaft being driven by a motor.

5. Texturizing apparatus according to claim 1,

' wherein the hooks are kept in the slots by both the inner wall of the fixedd outer cylinder and a spring housed in an annular cavity extending circumferentially around the outer wall of the rotatable inner cylin der.

6. Texturizing apparatus according to claim 1, wherein the slots in the rotatable inner cylinder define projections that at their upper end are shaped in relation to the form that one wishes to impart to the undulations of the yarn undergoing texturizing.

Claims

3. Texturizing apparatus according to claim 1, wherein the length of the hooks is correlated to the difference in level between the two rectilinear sections of the guiding groove and to the length of the slots, such that when the base of the hooks is inserted in the lower part of the guiding groove the hooks are positioned completely within the slots of the rotatable inner cylinder, for a depth which depends on the desired wave height, and when the base is inserted in the upper part of the guiding groove the crooked ends of the hooks project completely out of the slot.

5. Texturizing apparatus according to claim 1, wherein the hooks are kept in the slots by both the inner wall of the fixedd outer cylinder and a spring housed in an annular cavity extending circumferentially around the outer wall of the rotatable inner cylinder.