US3292354A

US3292354A - Apparatus for processing yarn

Info

Publication number: US3292354A
Application number: US449487A
Authority: US
Inventors: Frederic E Chalfant; Guy E Perkins
Original assignee: Leesona Corp
Current assignee: Leesona Corp
Priority date: 1965-04-20
Filing date: 1965-04-20
Publication date: 1966-12-20
Anticipated expiration: 1983-12-20
Also published as: CH438570A; GB1136746A

Description

Dec. 20, 1966 F. E. CHALFANT ET AL APPARATUS FOR PROCESSING YARN Filed April 20, 1965 2 Sheets-Sheet 1 INVENTORS. v FREDERIC E. CHALFANT GUY E. PERKINS I ATTYS.

United States Patent 3,292,354 APPARATUS FOR PROCESSING YARN Frederic E. Chalfant and Guy E. Perkins, Warwick, R.I., assignors to Leesona Corporation, Warwick, R.I., a corporation of Massachusetts Filed Apr. 20, 1965, Ser. No. 449,487 7 Claims. (Cl. 57-34) The present invention relates to apparatus for the processing of yarn having thermoplastic qualities, and has particular application to an improved heating means for controlling the temperature of the yarn in connection with the texturizing thereof.

Prior to the present invention it has been the practice to process yarns having thermoplastic qualities to form textured yarns such as torque stretch yarns, bulk yarns, and the like, by methods including the step of passing the yarn through a heating zone which elevates the temperature of the yarn to a level at which the molecules of the yarn may be reoriented so that upon cooling the yarn is possessed of a permanent set characterized by a tendency of the yarn to return to the condition it had at the time of heating. When making torque stretch yarns, while passing through the heating zone, the yarn is twisted so that the processed yarn has a tendency to return to the twisted condition when it is later untwisted. The twisting and untwisting is normally accomplished by a false twist means such as a spindle which imparts twist to the yarn in advance of the spindle and permits removal of the twist following passage through the spindle. During this processing, the tension and the heat applied to the yarn are correlated to the linear travel of the yarn through the heating zone and to the degree of twist which is imparted to the yarn by the false twisting spindle.

The linear speed of yarn thorugh the heating zone has been increased substantially with the improvement of the processing apparatus, and it has been found that a twist gradient exists within the heating zone, which gradient increases as the speed of travel increases. At slow speeds,

the twist gradient is confined to a short length of yarn at the entrance end of the twisting zone. At higher speeds, however, the length of yarn which possesses the twist gradient increases to an extent that at extremely high speeds the heat and tension do not have the same correla tion to the twist throughout the entire heating zone as they do at the lower speeds. It has further been discovered that the length of the twist gradient in the yarn is greater when the yarn is cool than when the yarn is heated, and with prior art apparatus operating at extremely high speeds, the temperature of the yarn does not attain the desired setting temperature until it has traveled some distance into the heating zone.

With the foregoing in mind, it is a primary object of the present invention to provide improved apparatus which effectively preheats the yarn prior to its entry into the heating and twisting zone so as to accelerate the heating of the yarn within the zone and thereby reduce the time interval within the heating and twisting zone which is required to cause the yarn to attain the desired heat setting temperature.

More specifically the present invention provides a novel preheater for yarn which elevates the temperature of the yarn to a point below the temperature necessary for molecular reorientation of the yarn, in advance of its entry into the twisting and heating zone of the processing apparatus.

The present invention provides apparatus insuring preheating of the yarn without imparting additional twist to the yarn during the preheating operation so that the entire twist of the yarn is added in the heating and twisting zone per se.

The present invention provides tension control for the yarn in the preheating zone to control the tension thereof in correlation to the size of the yarn, the speed thereof, and the temperature of the preheater.

All of the objects of the invention are more fully set forth hereinafter with reference to the accompanying drawing in which:

FIG. 1 is a transverse sectional view through a multistation yarn processing apparatus embodying a preheating device in accordance with the present invention;

FIG. 2 is a fragmentary view in front elevation of the apparatus shown in FIG. 1;

FIG. 3 is a perspective view of the preheater embodiment embodied in the apparatus of FIGS. 1 and 2;

FIG. 4 is a sectional view on a horizontal plane through the preheater shown in FIG. 3; and

FIG. 5 is a fragmentary view similar to FIG. 3 illustrating another embodiment of preheater for use in connection with apparatus similar to that shown in FIGS. 1 and 2.

The apparatus of FIGS. 1 and 2 is basically similar to that shown in US. Patent No. 3,152,436 issued October 13, 1964 to C. J. Dudzik et al. This apparatus comprises a multistation machine, each station including two

false twist spindles

10 and 20 operable to be rotated at a speed commensurate with the rate of travel of the yarn therethrough and including a twist trapper therein for twisting the yarn below the spindle and untwisting the yarn above the spindle. The untwisted yarn from each spindle is passed around a pair of tension-controlling feed rollers 11, 21 and from there to a processed-yarn take up

device

12, 22. The take up device 12 for the spindle 10 is disposed below and in front of the feed rolls 11 and the takeup device 22 for the spindle 20 is disposed a like distance above and in front of the feed rolls 21.

A heating and twisting zone underlies each of the spindles 1t) and 20 and includes a heater plate 31 common to all of the heating zones which is heated by suitable heating elements 32 extending along the length of the multi-station apparatus. The heater plate is surrounded by block insulation 33 having grooves or

slots

14 and 24 respectively in alignment with the

spindles

10 and 20. A threading device 34, such as shown in Dudzik Patent No. 3,094,761, is operatively associated with the heater plate 31 to facilitate threading of the yarns through the grooves or

slots

14 and 24. Means is provided at 15 and 25 respectively to arrest the travel of the twist from the opera-. tion of the

spindles

10 and 20 so that the yarn in advance of the twist trappers 15 and 25 has the same twist condition that it possesses on the

supply packages

16 and 26. As shown, the yarn from the

packages

16 and 26 is passed upwardly toward the heating zone through

suitable disc tensions

17 and 27 respectively.

The

disc tensions

17 and 27 isolate the packages from the remainder of the apparatus so that variations in tension occasioned by the unwinding of yarn from the packages are controlled as the yarn passes beyond the disc tensions.

In accordance with the invention, heated feed roll assemblies 19 and 29 respectively are mounted intermediate the

disc tensions

17, 27 and the twist trappers 15, 25. As shown, the heated feed roll assemblies 19 and 29 are similar in construction and only the assembly 19 will be described in detail. As shown in FIGS. 3 to 5, the assembly 19 includes a heater plate 41 having heating elements 42 associated therewith to maintain the desired temperature in the heating plate. Projecting forwardly from the heater plate 41 are

cylindrical heater blocks

43 and 44 secured in heat-conductive relationship to said heater plate and serving as heat sinks. The heater plate and blocks are provided with

bores

45 and 46 adapted to mount therein

drive shafts

47 and 48. The drive shafts are provided with

sleeve bushings

49 and 50 to afford rotary movement of said shafts within said blocks. Feed rolls are mounted on the the

shafts

47 and 48 and, in the present instance, consist of hollow

cylindrical shells

53 and 54 surrounding the

cylindrical blocks

43 and 44 respectively and rotatable thereon by reason of a keyed connection at 55 and S6 to the

drive shafts

47 and 48 respectively. It should be noted that the heater plate 41 is offset rearwardly from the heater plate 31, so that the yarn, as it leaves the roll 54, is in vertical alignment with the heating surface of the plate 31 and is free to bear against the plate in heat-transfer relationship therewith. As shown in FIG. 1, the

drive shafts

47 and 48 have suitably geared driving connections 55 to drive the

rolls

53 and 54 at the same surface speed. The entire assembly is contained in an insulated housing, in the present instance formed in two

parts

57 and 58 respectively, the front part 58 being readily removable for threading up and for observation of the passage of the yarn over the feed rolls.

In the embodiment shown in FIGS. 1 to 4, the

shells

53 and 54 are grooved as indicated to maintain the yarn runs about the feed rolls separated as they travel thereon. The surface of the grooved rolls is preferably highly polished or sufficiently smooth to afford freedom. for the yarn to slip thereon, permitting contraction or shrink- I age of the yarn as it travels over the heated feed rolls The upper feed rolls 11, 21 and the lower feed roll assemblies 19, 29 are correlated in speed to impart the desired tension to the yarn in the heating and twisting zone below the

false twist device

10, 20. The tension heating and twisting zone. In the present instance, the

nip of said

rollers

154 and 160 is in vertical alignment with the groove 114 of the overlying heater assembly. The roller 160 is similar in construction to the roller 154, consisting of a cylindrical shell mounted for rotation on a cylindrical heater block which is secured to i a lever 162 pivoted to the heater plate as indicated at 163 provide a positive pinch between the rollers 160 and on the yarn in the preheating zone within the heated feed roll assembly 19 is controlled by the number of runs or wraps of the yarn around the

rolls

53 and 54, taking into consideration the tension imparted by the disc tensions in advance thereof. The tension desired in the preheating zone on the heated feed rollers is dictated by the speed and denier of the yarn and the temperature of the preheater in relation to the amount of shrinkage which is desired in this zone. For example, when operating the heating and twisting zone in the range of 430 F. to 480 F., as when processing nylon, the temperature of the preheating zone should be in the range of 270 F. to 330 F. This temperature range, which is below the temperature necessary to reorient the molecules of the nylon, provides the best results with respect to skein shrinkage, strength, and elongation of the nylon being texturized. The number of filaments, the denier, and the type of nylon determine the specific temperatures desirable for operation, as is now well known in the art. It i has been found that the greatest uniformity in the finished texturized yarn has been obtained when the tension on the yarn in the preheating zone is maintained at a minimum value to afford maximum shrinkage of the yarn while obtaining full heating of the yarn to the temperature level desired.

In many instances it is preferred to employ a straightsurfaced or nongrooved feed roller in the preheater and to employ a positive nip between cooperating nip rollers as the yarn enters the preheater and as the yarn leaves the preheater. When using a positive nip, the twist trapper of the previous embodiment may be bypassed, or omitted entirely. FIG. 5 shows at 119 an embodiment of preheater employing a nip roller cooperating with the main feed roller in a yarn preheater. To this end, the preheater 119 is constructed similarly to the preheater 19 including a heater plate 141 having heating elements 142 and

feed rollers

153 and 154. A twist trapper 115 is provided in the event that it is desired. The

feed rollers

153 and 154 are positively driven in a manner similar to the

rollers

53 and 54, but the roller 154 has a smooth circumferential surface in lieu of the grooved surface used in the previous embodiment. A smooth nongrooved nip roller 160 is provided to bear against the surface of the roller 154 at the point where the yarn disengages the roller 154 in its passage beyond the preheater into the 154 to prevent travel of the twist into the yarn wrapped around the

rolls

153 and 154 and to insure effective heattransfer contact between the yarn and the surface of the rolls. identical to the assembly 19 described above.

It is apparent that the novel preheater assemblies of the present invention afford fully effective heating of the yarn up to the desired temperature level in a minimum of.

space and with maximum effectiveness. Proper preheating of the yarn reduces the time required for the yarn to reach the setting temperature in the heating and twisting zone which is necessary to effect reorientation of the molecules of the yarn to yarn set the same with the result that the total twist imparted to the yarn by the false twisting device is effective throughout the entire length of the.

heating zone and the treatment of the yarn is therefore uniform regardless of the linear speed of yarn travel through the apparatus, thereby providing greater uniformity in the textured yarn produced thereon.

While particular embodiments of the present invention has been herein illustrated and described it is not intended to limit the. invention to such disclosure but changes and modifications may be made therein and thereto within the scope of the following claims.

What is claimed is:

1. In apparatus for processing yarn having thermoplastic qualities comprising false-twisting means operable to twist the yarn in advance thereof and to untwist the yarn thereafter, a heating zone in advance of said false twist means operable to heat the yarn to a temperature sufficient to afford molecular reorientation of the molecules of the yarn while it is twisted, supply means for said yarn to supply yarn to said heating zone, delivery feed rolls to receive the untwisted yarn from said false twist means, and yarn take up means operable to collect. the yarn from said delivery feed roll means; the improvement comprising a preheating assembly intermediate said supply means and said twisting and heating zone to uniformly heat the yarn to a temperature below the temperature necessary to effect reorientation of the molecules of the yarn, said preheater assembly comprising a pair of spaced apart feed rolls, drive means for said feed rolls operable in timed relation to the delivery feed rolls so as to control the tension of the yarn intermediate said delivery and said preheater feed rolls, and means to heat said preheater feed rolls to a preselected temperature to effect heating of the yarn to the desired temperature below the temperature necessary to effect reorientation of the.

molecules of said yarn.

2. A preheater assembly according to claim 1 wherein said preheater assembly comprises a heater plate, means to heat said plate to a predetermined temperature, and heater blocks projecting outwardly from said plate and connected thereto in heat-transfer relationship therewith, said preheater feed rolls comprising cylindrical shells surrounding said blocks .and mounted for rotation relative thereto, said blocks serving as heat sinks to maintain the temperature of said preheater feed rolls at said preselected temperature level.

3. A preheater assembly according to claim 2 wherein.

said blocks are cylindrical in form whereby said shells closely surround said blocks to be heated thereby.

In other respects, the preheater assembly 119. is

4. Apparatus according to claim 1 wherein said heated feed-rolls consist of a large roller and 'a small roller said rollers being spaced apart and driven at the same surface speed.

5. Apparatus according to claim 4 wherein said rollers are grooved to receive and maintain separate the successive runs of yarn wrapped therearound.

6. Apparatus according to claim 4 wherein said large roller is straight-surfaced, and including a straight-surfaced nip roller biased into engagement with said large roller to eifect a positive nip on the yarn as it enters and leaves said heated feed rolls.

7. Apparatus according to claim 4 wherein the nip of said straight-surfaced rollers is disposed in vertical alignment with yarn path in said heating and twisting zone.

References Cited by the Examiner UNITED STATES PATENTS Stockly 57-34 Ubbelohde 57-34 Maier et al. 57-34 Evans 57-34 Enneking 5734 Wegener et al 57-34 Crouzet 57-157 FRANK J. COHEN, Primary Examiner.

15 D. E. WATKINS, Assistant Examiner.

Claims

1. IN APPARATUS FOR PROCESSING YARN HAVING THERMOPLASTIC QUALITIES COMPRISING FALSE-TWISTING MEANS OPERABLE TO TWIST THE YARN IN ADVANCE THEREOF AND TO UNTWIST THE YARN THEREAFTER, A HEATING ZONE IN ADVANCE OF SAID FALSE TWIST MEANS OPERABLE TO HEAT THE YARN TO A TEMPERATURE SUFFICIENT TO AFFORD MOLECULAR REORIENTATION OF THE MOLECULES OF THE YARN WHILE IT IS TWISTED, SUPPLY MEANS FOR SAID YARN TO SUPPLY YARN TO SAID HEATING ZONE, DELIVERY FEED ROLLS TO RECEIVE THE UNTWISTED YARN FROM SAID FALSE TWIST MEANS, AND YARN TAKE UP MEANS OPERABLE TO COLLECT THE YARN FROM SAID DELIVERY FEED ROLL MEAS; THE IMPROVEMENT COMPRISING A PREHEATING ASSEMBLY INTERMEDIATE SAID SUPPLY MEANS AND SAID TWISTING AND HEATING ZONE TO UNIFORMLY HEAT THE YARN TO A TEMPERATURE BELOW THE TEMPERATURE NECESSARY TO EFFECT REORIENTATION OF THE MOLECULES OF THE YARN, SAID PREHEATER ASSEMBLY COMPRISING A PAIR OF SPACED APART FEED ROLLS, DRIVE MEANS FOR SAID FEED ROLLS OPERABLE IN TIMED RELATION TO THE DELIVERY FEED ROLLS SO AS