US3041706A - Apparatus for processing cold-drawable textile filaments - Google Patents

Description

July 3, 1962 BROMLEY ET AL 3,041,706

APPARATUS FOR PROCESSING COLD-DRAWABLE TEXTILE FILAMENTS Filed Nov. 1'7, 1960 FIG.

KM ATTORN United States Patent O 1 3,041,706 APPARATUS FOR PROCESSHJG COLD-DRAW- ABLE TEXTILE FILAMENTS James E. Brantley and William H. Hills, Pensacola, Fla,

assignors, by mesne assignments, to Monsanto Chemical Company, a corporation of Delaware Filed Nov. 17, 1960, Ser. No. 70,020 5 Claims. (Cl. 28-1) This invention relates to apparatus for processing colddrawable textile filaments formed from a thermoplastic polymer. More particularly, this invention relates to apparatus for continuously stretching and continuously deforming substantially parallel synthetic continuous textile filaments of the nylon type, whereby such filaments are rendered potentially crimpable.

Continuous synthetic cold-drawable filaments can be formed from nylon polymers and the like by the wet, dry, or melt spinning processes, the last mentioned process being employed in the commercial production of most, if not all, of the nylon filaments made today. The freshly formed nylon filaments generally are not highly oriented and have relatively low tensile strengths as compared to highly oriented nylon filaments in which the molecules are aligned or oriented in the direction of the filament axis. To orient nylon filaments and thereby to increase greatly the strength thereof, they may be stretched to a desired extent by attentuating them by means of thread advancing devices such as two godets or two other thread advancing means operated at a predetermined peripheral speed differential. In the cold-drawing of continuous filaments of nylon it is known that stretching is accomplished advantageously when the point at which stretching occurs is fixed or localized by mechanical or thermal means. The localization of the stretch point is carried out ordinarily with the employment of a yarn braking device or the like located between two stretching roll devices.

Unlike wool, synthetic filaments are relatively straight and have a smooth, slick surface, thereby not being particularly adapted for spinning into spun yarn by the conventional spinning systems. To facilitate the carding and/ or combing and drafting operations to which synthetic staple fibers are subjected in connection with spinning them into spun yarn, it is essential to crimp them so that they will have a satisfactory contour or pattern to permit spinning thereof into spun yarn by means of conventional textile processing equipment. Numerous devices and processes have been proposed to impart this desired crimp or crinkle to synthetic continuous filaments. One known form of a crimping device uses toothed gearing or serrated wheels which are heated and adapted to receive the straight continuous filaments and to shape them by compressive forces into a crimped configuration.

While continuous filament yarns have the advantage of greater evenness and superior strength, they have several undesirable properties, including low heat insulating values, lack of bulkiness desired for some end uses, and low covering power. Many attempts have been made in the past to impart some of these desirable properties of spun yarn to continuous filament yarn. In addition to the fact that the expense of manufacturing the yarn is increased considerably, there are unfortunately certain well recognized disadvantages associated with the prior devices and methods for imparting bulk to continuous filament yarn.

One of the disadvantages of apparatus using crimping gears is that, because of contact with the heated yarn, the temperature of the crimping gear in contact with the yarn slowly rises between dofis. This results in a gradual change in the crimped characteristics of the yarns as a run proceeds. With this problem in mind, an object of this invention is to provide a yarn crimping apparatus having crimping gears which are cooled to prevent a substantial temperature rise.

3,041,706 Patented. July 3, 1962 Another object of this invention is to provide a novel and improved yarn treating apparatus.

Another object of this invention is to provide an apparatus for commercially producing a thermoplastic continuous multifilament yarn having a fluffy, stretchable character and possessing many properties associated with spun yarn while retaining many properties associated with filament yarn such as strength and freedom from pilling.

Another object of this invention is to provide an an paratus for drawing and deforming nylon filaments in a single operation so as to render same potentially highly cr-impable.

Still another object of this invention is to provide an apparatus for simultaneously deforming and cooling nylon filaments immediately after said filaments are oriented by a drawing operation.

A further object of this invention is to provide an apparatus utilizing crimping gears which are cooled to prevent a substantial temperature rise.

A still further object of this invention is to provide an improved stretching and deforming apparatus for processing nylon or the like.

In one embodiment of the invention cold-drawable synthetic filaments are fed by a power driven feed roller through a heat-stretch zone wherein the filament-s are heated and stretched and from which the filaments are fed between positively driven intermeshing crimping gears, the teeth of which are cooled to limit temperature rise. The cooling is achieved by the use of a nozzle which directs cooling air onto one of the crimping gears.

Other objects and advantages of the present invention will become apparent when the following description of the invention is read in conjunction with the appended drawing, in which:

FIGURE 1 is a schematic view showing the general arrangement of the elements making up one embodiment of the invention; and

FIGURE 2 is an enlarged fragmentary view showing the positioning of an air nozzle relative to one of the crimping gears.

In accordance with this invention there is provided an improved stretching and deforming machine for processing nylon or like synthetic continuous filament yarn, the machine being constructed for highly efficient and economical operation. This is made possible by the arrangement of a feed roll assembly and a set of drawing and deforming toothed wheel members, together with means for heating the yarn such as a heated draw or stretch pin, a heated plate, a heated tube, and the like interposed between the said roll assembly and said members. From a suitable source the yarn is fed to the said feed roll assembly after being passed around or through a suitable tensioning device. At least one of the rolls is positively driven. The objectives of the roll assembly are the provision of a supply of yarn at a predetermined rate and the provision that the yarn will not slip therethrough or therearound due to the stretch tension subsequently applied.

In the yarn path forward with respect to the roll as sembly and the heating means there are disposed a pair of crimping gears driven in unison and intermeshing in close relationship without coming in contact with each other. At least one of the crimping gears is positively driven at a predetermined increased speed relative to the delivery speed of the roll assembly such that a stretch is imparted to the yarn between the said roll assembly and said gears. The yarn is directed in operation between the gears and preferably around part of the periphery of one of the gears and thence around an idle roll for a desired number of times or wraps with the yarn taking a path that progressively moves longitudinally forward with respect to the point where the yarn initially is passed between the gears. By proper spacing of the idle roll relative to the crimping gears, the yarn is intermittently engaged and disengaged between the crimping members either in a random or definite pattern.

The crimping members not only serve to deform the filaments of the yarn but'also function to cool rapidly or to quench and thereby to harden them as they pass therebetween. Hence, the members are made preferably of heat conductive material.

To insure that the temperature of the crimping gears does not rise to an undesirable value during a run, a nozzle is provided for directing cool air onto one of the crimping gears. This holds down the temperature of the crimping gears to give a more uniform crimp characteristic. After being stretched and deformed in such manner, the yarn is taken up in a well known manner.

In the continuous filament yarn treating apparatus shown schematically in FIGURE 1, a thermoplastic colddraw-able yarn It such as nylon or the like, composed of a bundleof smooth, substantially parallel filaments that have not been fully oriented, is supplied from a yarn source 11 on a bobbin 12. Since the yarn is not completely oriented, it is necessary to extend the yarn to be processed in order to obtain the optimum degree of molecular orientation therein. The yarn It is passed over and around one end of the bobbin 12 and is threaded conventionally around a snubbing bar 13 which functions as a simple tensioning device to assist in maintaining an orderly and uniform supply of yarn. From the tensioning device or bar 13 the yarn is passed through a yarn guide 14 and then to a pair of feed rolls 15 that withdraw the yarn from the bobbin lz and supply it at a predetermined delivery speed. The rolls 15 have parallel axes and engage each other in operation to nip sufficiently the yarn passing therethrough so that slippage or free-flight of the yarn between the rolls is prevented.

From the feed rolls 15. the yarn It? is led downwardly and around a heated stretch or draw pin 16 of a well known type where the majority of the attenuation of the yarn occurs. The pin, mounted so that it is axially askew with respect to the axes of the feed rolls 15, has a smooth yarn contact surface. After being passed around the heated pin 16. a desired number of times, the yarn It is directed downwardly between rotatably mounted and axially parallel crimping gears 17 and 18 positioned immediately beneath the pinlfi and having a plurality of uniformly circumferentially spaced and longn'tudinally extending teeth 20 that mesh in closely spaced adjustment. The gears 17 and 18 are keyed to shafts 21 and 22, re-

7 spectively. To drive the crimping gears in unison there are provided meshing spur gears 23 and 24 mounted on the shafts 21 and 22, the shaft 22 being driven by a motor 19 of a Well known type.

As the teeth 24 mesh, the yarn 10 is subjected to laterally applied stresses increasing and decreasing in intensity as the yarn approaches and leaves the horizontal plane in which the axes of the crimping gears lie and where said teeth engage the notches defined by said teeth to the greatest extent. After being directed around part of the periphery of the gear 17. the yarn is directed tangentially therefrom and then around part of the periphery of an idle roll 25 spaced from the gear 17 and mounted on a supporting frame 26, the frame 26 also supporting the other parts of the apparatus. The yarn is wound around the gear 17 and the idle roll 25 to, form a plurality of wraps as shown in the drawing. The axis of the roll 25 is positioned at a slightly inclined angle with respect to the axes of the gears 17 and 18 so as to insure proper longitudinal distribution, on and advancement along the peripheries of the gear 17 and the roll 25, thus preventing superposition of the wraps thereon. In other words, the yarn wrapped around the gear 17 and the horizontally spaced idle roll 25 assumes generally the shape of a flattened helix, the convolutions of which being spaced apart, so that the yarn advances along the gear 17 from the inboard to the outboard thereof during rotation of the gears 17 and 18.

To insure that uniform results are obtained in the crimping operation, an air nozzle 34 is provided. The nozzle 34 is connected to a source 35 of cool air or other gas. The nozzle 34 extends between the yarn wraps on the gear 17 and the idle roll 25 and is curved at the end to direct cooling air onto the gear 17. Stated in an other way, the nozzle 34 extends into the central part of the flattened helix defined by the yarn wraps and then bends toward the gear 17.

From a study of FIGURE 2, it will become apparent that the nozzle 34 is positioned to direct a stream of cooling air onto the crimping gear 17 but not onto the moving yarn 10. This permits the yarn 10 to retain its heat while at the same time holding down the temperature of the gear 17. Since the yarn 10 is not wrapped around the crimping gear 18, it is not necessary to cool this gear.

It is well known that temperature has great importance in the crimping of thermoplastic yarns. Thus, the temperature of the gear 17 will have an affect on the crimping operation. If the temperature of the gear 17 is permitted to vary widely, the result will be wide variations in the crimped characteristics of the yarn. In fact, without the air nozzle 34, the temperature of the crimping gear 17 would slowly rise as the heated yarn is moved over it. This would naturally cause changes in the final characteristics of the yarn. By using the stream of air to cool the gear 17, a substantially uniform result is achieved, since the crimping gear 17 is cooled to pre ventundesirable temperature rises.

After forming the outermost convolution of the helix,

the yarn is fed vertically downwardly through a yarn pigtail guide 29, which is mounted below the crimping gears. The yarn is then taken up in a conventional manner by a suitable form of package building apparatus such as a ring twisting assembly which comprises a bobbin 28 adapted to be rotated by driven belt 30 in a conventional manner to form a yarn package 31. The assembly further includes a conventional vertically-reciprocated ring 32 carrying a traveller 33 adapted to revolve freely around the bobbin 28 as the yarn is twisted a desired amount and wound ontothe bobbin.

, It is to be understood that this embodiment of the invention may be altered or modified and that other embodiments may be contemplated without departing from the spirit and scope of the invention.

What is claimed is: V

1. An apparatus for crimping a yarn, comprising a frame, a pair of yarn crimping gears mounted on the frame, means for driving the yarn crimping gears, an idle roll mounted on the frame at a location spaced from one of the yarn crimping gears for cooperating with said one gear to form a plurality of wraps in a heated yarn in such a manner that the yarn engages only a portion of said one gear, and a nozzle mounted inside said wraps for directing a cooling medium onto that portion of said one gear not engaged by the yarn'to prevent a temperature rise in said one gear.

2. An apparatus for crimping a yarn, comprising a frame, a pair of meshed crimping gears mounted on the frame, means for driving the crimping gears, an idle roll mounted on the frame at a position spaced from one of the crimping gears for cooperating with said one crimping gear to form a plurality of wraps in a heated yarn in such a. manner that the yarn is in engagement with only a portion of said one gear, and an air nozzle positioned between the idle roll and said one crimping gear in such a manner as to direct a stream of cooling air onto that portion of said one crimping gear which is not in engagement with the yarn.

3. An apparatus for crimping a yarn, comprising a frame, a yarn crimping element rotatably mounted on the frame, guide means on the frame for directing the yarn across the crimping element in such a manner that said yam is in contact With the crimping element along an are on the periphery of said crimping element, and a nozzle positioned adjacent to the side of the crimping gear opposite the said are for directing a cooling fluid onto said opposite side.

4. An apparatus for crimping a yarn, comprising a frame, a crimping gear rotatably mounted on the frame, an idle roll mounted on the frame and positioned from the crimping gear for cooperating with said gear to form a plurality of yarn wraps in such a manner that the yarn is in engagement with only a pontion of the crimping gear, and a nozzle positioned between the crimping gear and the idle roll for directing a stream of cooling fluid onto the crimping gear at a point spaced from said portion of said crimping gear.

5. An apparatus for crimping a yarn, comprising a frame, a crimping gear rotatably mounted on the frame, a

roll rotatably mounted on the frame at a point spaced from the crimping gear for cooperating with the crimping gear to form a plurality of wraps around said gear and said roll in such a manner that the yarn is in engagement with only a portion of the gear, said roll having its axis of rotation inclined relative to the axis of rotation of the crimping gear so that the yarn advances longitudinally along said gear as said gear is rotated, and a nozzle positioned between the gear and the roll in such a manner as 10 to direct a stream of cooling fluid onto that portion of said gear not in engagement with the yarn.

References Cited in the file of this patent UNITED STATES PATENTS 15 2,313,630 Dockerty Mar. 9, 1943 2,394,165 Getaz Feb. 5, 1946 2,855,749 Eshuis Oct. 14, 1958

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