US3234626A

US3234626A - Apparatus for hot and cold crimping of textile filaments

Info

Publication number: US3234626A
Application number: US319240A
Authority: US
Inventors: James M Faria
Original assignee: Monsanto Co
Current assignee: Monsanto Co
Priority date: 1963-10-28
Filing date: 1963-10-28
Publication date: 1966-02-15
Anticipated expiration: 1983-02-15
Also published as: IL22327A

Description

- Feb. 15, 1966 J. M. FARIA 3,234,626

APPARATUS FOR HOT AND COLD CRIMPIN OF TEXTILE FILAMENTS Filed Oct. 28, 1963 INVENTOR. JAMES M. FARIA mm. M

ATTOR EY United States Patent Ofifice 3,234,526 Patented Feb. 15, 1966 3,234,626 APPARATUS FOR HOT AND COLD CRIMPING F TEXTILE FILAMENTS James M. Faria, Decatur, Ala., assignor to Monsanto Company, a corporation of Delaware Filed Oct. 28, 1963, Ser. No. 319,240 4 Claims. (Cl. 281) This invention relates to apparatus for continuously stretching and continuously deforming substantially parallel synthetic continuous textile filaments formed from a thermoplastic polymer, and particularly filaments of the nylon type, whereby such filaments are rendered more resistant to interfilament slippage. More specifically, this invention relates to apparatus for improving filament cohesion of nylon continuous filament yarn.

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. T o orient nylon filaments and thereby to increase greatly the strength thereof, they may be stretched to a desired extent by attenuating them by means of thread advancing devices such as two godets or two other thread advancing means operated at a predetermined peripheral speed ditferential. In the colddrawing 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.

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, low covering power, poor tuft definition, and poor filament cohesion. Many attempts have been made in the past to impart to continuous filament yarn some of the desirable properties that are inherent in spun yarn.

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 impart a potential or temporary crimp to them by compressive forces. The potential crimp is later developed by reheating the filamentary material during dyeing or a steaming operation after the filaments have been processed and converted into articles of manufacture. As taught by the prior art, the potential crimp may be developed prior to takeup of the potentially crimped filaments by passing the same, while relaxed, through a heated chamber wherein the filaments again assume their original crimped configuration. In other words, straight continuous filaments are deformed by the toothed gears during the stretching operation and then become straight again until heated, at which time, the filaments assume the deformed or crimped configuration previously caused by the gears, whereby a permanent crimp is imparted to the filaments.

In certain manufacturing processes, as for example, tufting operations and the like, it is preferable to produce the articles of manufacture prior to developing the original potential crimp of the filaments. This presents a serious problem to the textile industry because the yarn does not possess a high degree of filament cohesion. This lack of cohesion allows a filament splaying condition to occur which adversely affects the processing thereof on conventional textile equipment, particularly tufting operations. In the case of staple fiber the filament cohesion is so poor that its use in producing spun yarns is not practical. However, it has been found that filamentary cohesion is increased substantially when a yarn is first crimped while hot, and subsequently crimped in a stulfer box while cold. A particular advantage of the cold crirnp is that an actual crimp is imparted to the yarn without disturbing the original potential crimp. Therefore, the yarn can be processed efficiently prior to development of the original potential crimp. With this in mind, an ob ject of this invention is to provide a crimping apparatus which will improve the filament cohesion of synthetic filaments by increasing inter-filament resistance to slippage.

Another object of this invention is to provide an apparatus for imparting a crimped condition to synthetic filaments of nylon and the like.

Another object of this invention is to provide a novel and improved yarn treating apparatus.

Still another object of this invention is to provide an apparatus for drawing, deforming, and crimping nylon filaments in a single operation so as to improve filament cohesion, tuft definition, covering ability, dyeing and the like while eliminating filament splaying, row definition, and a subsequent twisting operation.

A further object of this invention is to provide a novel and improved apparatus for pre-conditioning nylon filaments so as to permit processing of staple fiber formed therefrom on conventional eqipment without loss of bulk.

Other objects and advantages of the present invention will become apparent from a study of the following specification, claims, and drawing. A preferred embodiment of the apparatus of the present invention will now be described with reference to the accompanying drawing wherein FIGURE 1 discloses a schematic view in perspective with principal elements in location illustrating apparatus suitable for preparing thermoplastic filaments possessing a high degree of cohesion among said filaments.

FIGURE 2 is an enlarged cross-sectional view of the stuffer box.

In accordance with the present 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 efiicient and economical operation. This is accomplished by the novel construction and arrangement of a feed roll assembly wherein at least one of the rolls is positively driven 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 feed roll assembly after passing around or through a suitable tensioning device. The objectives of the roll assembly is the provision of a supply of yarn at a predetermined rate and to guard against slippage of the yarn because of stretch tension subsequently applied.

Positioned in the yarn path forward of the roll assembly and heating means is 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 delivery speed of the roll assembly such that a stretch is imparted to the yarn between the roll assembly and gears. In operation the yarn is directed 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. Temperature of the crimping members, is maintained at a desired level by a coolant gas being directed on one of the said members. I

Thereafter, the yarn is advanced vertically downwardly into a stutfer box by a pair of feed rolls associated there- 'with. -The stuffer box is provided with a clapper bar which restricts the movement of the yarn thereby causing aback-pressure to develop within the stuffer box chamber. Consequently, the yarn assumes a position in the chambet in the form of a series of folded layers and is pressed therein to impart a crimpedcondition to the folded yarn at each bend of thesaid yarn. The cold crimp imparted to the yarn improves the inter-filament resistance to slippage of the filaments comprising'the yarn. After being stretched, deformed and crimped in such manner as described herein above, the yarn is taken up in a well known manner.

In the continuous filament yarn treating apparatus shown schematically in FIGURE 1, a thermoplastic colddrawable yarn 10, such as nylon or the like, composed of a bundle of 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 completed oriented, it is necessary to extend the yarn to be processed in order to obtain the optimum degree of molecular orientation therein. .The yarn source can be, for example, yarn package 11 doffed previously from a conventional spinning machine, or continuous yarn which has not been doffed previously from a spinning machine.

In operation, as shown, the yarn 10 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 '10 is passed througha yarn guide 14 and, then to a pair .of feed rolls .15 that withdraw the yarn from the bobbin 12. and supply it at a predetermined delivery speed.. The rolls 15 have parallel axes and engage each other in operation to nip sufiiciently 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 10 is led downwardly and around a heated streach 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 10 is directed downwardly between rotatably mounted and axially parallel crimping gears 17 and 18'positioned immediately beneath the pin 16 and having a plurality of uniformly circumferentially spaced and longitudinally extending teeth 20 that mesh in closely spaced adjustment. The

gears

17 and 18 are keyed to

shafts

21 and 22, re 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. j

As the teeth 20 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, only a fragment thereof being shown. The frame 26 also supports 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 nozzle34 is connected to a source 33 of coolair 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 another 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. 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 tem- .perature of the gear 17 will have an effect 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 prevent undesirable temperature rises. Accordingly, the yarn is somewhat 'cooler when leaving the crimper gears than the heated yarn advanced to the crimper gears.

After forming the outermost convolution of the helix, the yarn is fed vertically downwardly between a pair of feed rolls 35 and 36 positioned immediately below crimping gears17 and 18. The

rolls

35 and 36 are keyed to

shafts

37 and 38, respectively, and are driven by any well known suitable means, not shown.

As illustrated by FIGURE 2, a stuifer box 39 comprising a pair of

doctor blades

40 and 41, are positioned directly below and adjacent to the feed rolls to-form a chamber. A clapper bar 42 is pivotally mounted to doctor blade 41 inside the chamber. On the other side of doctor blade 41 is mounted an air cylinder 43 for actuating bar 42 to vary the opening in the bottom of the stuffer box chamber. Movement of the yarn through the chamber is restricted by the .clapper bar 42 while the feed rolls force the yarn into the stuifer box at a predetermined constant' rate whereby a back-pressure is developed therein causing the said yarn to be folded and packed in the form of uniform layers 44 in the chamber. The pressure exerted on the folded layers of the yarn in the'stutfer box chamber imparts a crimp or crinkle at each bend 45 in the yarn.

The crimping operation performed by the stulfer box 39 greatly increases the inter-filament resistance to slippage of the filaments thereby improving filamentary cohesion. This improvement is accomplished by reason of the fact that actual crimp is imparted to the yarn without requiring reheating thereof to enable processing of the yarn prior to development of the original crimp. From studying the schematic of the apparatus illustrated it becomes apparent that the texturized yarn is crimped initially by

gears

17 and 18 While heated, and immediately thereafter, actual secondary crimp is imparted to the yarn, when cold, by stufier box 39. Without the cold crimp, the yarn is comprised of a plurality of straight continuous filaments having poor filament cohesion.

From the stulfer box 39 the yarn is fed vertically downwardly through a yarn pigtail guide 46, which is mounted below the stuffer box. The yarn is then taken up in a conventional manner by a suitable form of package building apparatus such as a ring twist assembly which comprises a bobbin 47 adapted to be rotated by driven belt 47 in a conventional manner to form a yarn package 47. The assembly further includes a conventional vertically reciprocated ring 50 carrying a traveler 51 adapted to revolve freely around the bobbin 46 as the yarn is twisted a desired amount and wound onto the 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 I claim:

1. Apparatus for texturing and crimping successively a continuous filament yarn made from a thermoplastic material comprising, in combination:

(a) means for advancing yarn at a predetermined rate from a supply,

(b) means for heating the advancing yarn,

(0) means for attenuating and imparting to said yarn potential crimp while at an elevated temperature,

(d) means for cooling said attenuated yarn, and

(e) means for successively imparting a crimped configuration to said potentially crimped yarn after said yarn has been cooled thereby improving filamentary cohesion thereof.

2. An apparatus for texturizing and crimping a synthetic continuous filament yarn made from a thermoplastic comprising, in combination:

(a) a pair of rotatably mounted rolls for advancing a yarn at a predetermined rate from a supply,

(b) a pair of rotatably mounted crimping gears for receiving the yarn and advancing same at a predetermined increased rate as compared to the supply rate and adapted to impart a crimped, configuratory memory thereto,

(c) a yarn heating device in the yarn path between the advancing rolls and the crimping gears to heat said yarn,

(d) an idle roll positioned from the crimping gears for cooperating with said gears to form a plurality of wraps in the heated yarn,

(e) means for cooling the crimping gears, and

(f) means for receiving and compressing the cooled yarn in folded layers to impart an actual crimp therein after the same has passed between said crimping gears and around said idle roll several times without modifying said memory.

3. An apparatus for crimping a yarn comprising:

(a) a frame,

(b) a pair of yarn crimping gears mounted on the frame,

(c) means for driving the crimping gears,

(d) means for heating yarn being forwarded to said crimping gears,

(e) 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 the heated yarn in such a manner that the yarn engages only a portion of said one gear to impart a potential crimp to the heated yarn,

(f) means for cooling the said one gear,

(g) a pair of feed rolls having a stulfer box connected therewith mounted to the frame in tandem with the crimping gears and adapted to impose a mechanically induced permanent crimped configuration in the potentially crimped yarn whereby filamentary cohesive properties thereof are improved, and

(h) means for driving the feed rolls.

4. Apparatus for successively imparting potential crimp and permanent crimp to continuous filament yarn made from the thermoplastic material, said apparatus comprising, in combination:

(b) a yarn heating device positioned in the path of the yarn being advanced from said rolls for heating said yarn to an elevated temperature,

(c) a pair of rotatably mounted crimping gears for receiving said heated yarn and advancing same at a predetermined increased rate with respect to the supply rate whereby said yarn is attenuated and a potential crimp memory is imparted to said heated yarn,

(e) means for cooling and advancing said heated yarn from said crimping gears in a straight longitudinal condition to a stufier box chamber wherein a crimped configuration is imparted to said yarn at ambient temperature thereby improving filamentary cohesion properties of the yarn when reduced to staple fibers and formed into a yarn bundle.

References Cited by the Examiner UNITED STATES PATENTS 2,647,285 8/1953 Pfau 2872 2,917,784 12/1959 Spence et a1. 28-72 2,972,798 2/1961 Stanley et a1. 28-72 3,022,545 2/ 1962 Wylde et a1. 2872 3,041,706 7/1962 Bromley et a1. 281

DONALD W. PARKER, Primary Examiner.

Claims

1. APPARATUS FOR TEXTURING AND CRIMPING SUCCESSIVELY A CONTINUOUS FILAMENT YARN MADE FROM A THERMOPLASTIC MATERIAL COMPRISING, IN COMBINATION: (A) MEANS FOR ADVANCING YARN AT A PREDETERMINED RATE FROM A SUPPLY, (B) MEANS FOR HEATING THE ADVANCING YARN, (C) MEANS FOR ATTENUATING AND IMPARTING TO SAID YARN POTENTIAL CRIMP WHILE AT AN ELEVATED TEMPERATURE, (D) MEANS FOR COOLING SAID ATTENUATED YARN, AND (E) MEANS FOR SUCCESSIVELY IMPARTING A CRIMPED CONFIGURATION TO SAID POTENTIALLY CRIMPED YARN AFTER SAID YARN HAS BEEN COOLED THEREBY IMPROVING FILAMENTARY COHESION THEREOF.