US3423806A

US3423806A - Apparatus for shaping and guiding a textile tow

Info

Publication number: US3423806A
Application number: US654240A
Authority: US
Inventors: John Shuford Dickins
Original assignee: EI Du Pont de Nemours and Co
Current assignee: EIDP Inc
Priority date: 1967-07-18
Filing date: 1967-07-18
Publication date: 1969-01-28
Anticipated expiration: 1986-01-28

Description

Jan. 28, 19 69 J. s. DICKENS m ,8 6

APPARATUS FOR SHAPING AND GUIDING A TEXTILE Filed July 18, 1967 TOW o\ ('0 o) o o l 0 O l 0 o o o o INVENTOR ATTORNEY JOHN SHUFORD moms. m

United States Patent 4 Claims ABSTRACT OF THE DISCLOSURE An improvement in an apparatus for drawing and stuffer box crimping filamentary tow which allows a single tow to be run through the draw machine rather than a number of separate ribbons that later are combined to form the tow prior to crimping resulting in a higher permissible tow tension and the associated improvement in fiber properties, the improvement being a roller convergence guide arrangement operatively mounted between the draw machine and crimper comprising a pair of elongated cylindrical rollers vertically mounted on each side of the tow path and spaced apart a distance about equal to the crimper chamber width and at least four flanged elongated cylindrical rollers horizontally mounted in the tow path having substantially parallel longitudinal axes, said horizontal rollers being mounted between the vertical rollers and the pull rolls, the distance between the flanges corresponding to about the crimper chamber width.

BACKGROUND OF THE INVENTION Field of the invention This invention is concerned with the production of synthetic fibers. It is particularly concerned with that step in fiber production wherein a web of continuous filaments is converged and shaped after drawing into a narrow band suitable for entry into a stutter-box crimper.

Description of the prior art Various types "of equipment have been used for converging and shaping tows of fibers for stutter-box crimping. However, as production methods change, and as process improvements are made, the apparatus used in production must be changed. Apparatus for shaping tows is described in US. Patents 3,277,537 to Roeder et al.; 3,270,937 to Harrell; 3,248,103 to Tarbell; 3,231,958 to Chadwick; 3,145,429 to Resor; and 2,811,770 to Young. However, none of this equipment is satisfactory for operating under high tension according to the present invention. The apparatus of this invention gives a tow of improved properties.

Summary of the invention In order for fibers to process satisfactorily through textile operations which convert them into yarns, it is necessary that the fibers possess crimps. If fibers do not crimp spontaneously, it is necessary to impart crimp by mechanical means. The most useful method of doing this is by means of a stutter-box crimper. In this operation, the fibers in the form of tow of 400,000 to over 1,000,000 denier are passed through squeeze rolls and packed into a confined space under pressure, which causes the fibers to be crimped. If the band of tow is not uniform, it will not be evenly squeezed between the feed rolls of the crimper and crimping will be highly non-uniform. The fibers can also be damaged it squeezed non-uniformly. After crimping a tow should have the crimped fibers uniformly intermeshed so that the fibers hold together without splits in the web. Hence, the shaping of the tow preparatory to crimping is a highly critical step in fiber manufacture and must be done with a high degree of precision.

The present invention solves a problem which developed when a more suificient method was developed for drawing and heat-relaxing polyester fibers involving maintaining high tension on the fibers.

In order to achieve a high quality, evenly crimped tow band, tow must be shaped and formed for a given size crimper. The prior art utilizes stacker type guides by which a number of narrow tow ribbons which are separated by numerous guides in the draw machine are laid In an overlapping type of relationship to form the tow band desired for the crimper. Maintaining separation of the tow ribbons presents many processing problems as the ribbons must be separated prior to entry into the draw machine and also since there are numerous rolls within the draw machine over which the tow ribbons must pass. The problems are greatly complicated and magnified whenever the tow is subjected to high tensions as no guides may be used in the draw machine.

With the apparatus of the present invention, it is not necessary as required by the prior art stacking technique to keep tow ribbons separated from each other. The apparatus of this invention allows one tow band to be run through the draw machine and converged and shaped prior to the stutter-box crimper.

The present invention comprises an arrangement of low-friction flanged horizontal rollers along with vertical guide rolls to converge a web of continuous filaments from a width of 11 inches (28 cm.) or less to a width of 2 inches (5. cm.) or less, or from a width of 24 inches (61 cm.) or more to a width of 5 inches (12.7 cm.) or more. The converged fibers are evenly distributed in the form of a mass with a rectangular cross-section and crimp uniformly without fiber damage.

The present invention is best understood by reference to the attached figures.

Brief description 0 the drawing FIGURE 1 is a schematic drawing depicting the processing of a web of fibers through the steps of drawing, annealing (heat-relaxing), convergence, and crimping.

FIGURE 2 is a drawing of the specific apparatus of this invention showing vertical guide rolls and horizontal shaping rolls.

Referring to FIGURES 1 and 2, numeral 10 represents a web of filaments of about 11 inches (28 cm.) or less to about 2 ft. (0.6 meter) or more width prior to drawing. Numeral 1 refers to a series of feed rollers which control the web going into the drawing operation, 2 represents a spray zone where hot water or steam can be applied to the filaments, 3 shows draw rolls which operate at higher speeds than the feed rollers 1, 4 shows the annealing zone where the fibers are heated after drawing, 5 represents two vertical rollers for converging the web, 6 shows the flanged rollers which shape the tow into a rectangular band suitable for crimping, 7 represents puller rolls which maintain a high tension on the filaments comprising the tow, 8 shows the crimper, and 9 a belt on which the crimped yarn is deposited in a tensionless condition for final relaxation and drying.

Description of the preferred embodiment When operating with the apparatus of the present invention, the filaments from a number of spinning positions are combined into a web which may have a total draw denier from 400,000 or less to over 1,000,000 and a width of less than 1 ft. (0.3 meter) to more than 2 ft. (0.6 meter). After passing over a series of feed rollers, the web is sprayed with hot water as it is stretched by the draw rollers which operate at surface speeds of about 2.5 to about 5 or 6 times the surface speed of the feed rolls.

The web then passes over the heated rolls of the annealing zone. These rolls are preferably about 2 ft. (0.6 meter) in diameter and may conveniently be heated with steam. The web, still under high tension, is next converged and shaped by apparatus of the present invention. Because of the relatively high tension of the operation compared to previous processes (i.e. about 400% greater), the converging equipment must not produce friction with the yarn. Throughout the converging operation of the present invention, all contacts are with rollers.

The vertical rollers, being at least two in number, are usually spaced about 0.125 to 0.375 inch (0.32 cm. to 0.96 cm.) closer together than the distance between the flanges on the convergence rollers. Alternatively, the spacing between the vertical rollers is generally about 20% to 35% less than the distance between the flanges of the convergence rollers.

There are at least four flanged horizontal convergence rollers and they are most conveniently arranged as shown in FIGURE 1 though numerous equivalent arrangements are suitable. Because of the high tension on the tow, the strand of filaments spreads sufliciently to reach the sides of the flanges and are molded into a mass of tow of rectangular cross-section suitable for crimping. The distance between the flanges of the rollers is dictated by the crimper roll width and the crimper chamber Width. The crimper chamber width is preferably within the range of about 1.5 inches to about 7 inches.

The apparatus of the present invention, which utilizes the roller convergence guides for shaping the tow from a single tow web, can operate at a much higher tow tension than the prior art process in which a number of tow ribbons are separated through the draw machine and stacked to form a single tow band prior to crimping. Tow produced by the higher tension process allowed by the apparatus of the present invention exhibits superior properties to tow produced by the lower tension prior art process. Table I compares fiber properties of filaments from a tow converged as in the present invention with a tow of similar polyethylene terephthalate fibers converged by the prior art ribbon stacking process.

TABLE I Process of Prior art invention process Guides Tow denier-drawn 430, 000 430, 000 Denier per filament-drawn.. 1. 1. 5 Tow tension, grams/denier 0. 8 0.2 Tenacity alter drawing, grams/dent 5. 5 5. 5 Tenacity after crimping, grams/denier 5. 4 5. 3 Tenacity after relaxing, grams/denier 5. 1 4. 5 Dyeability not be operable with prior art equipment and yields filament tows with properties diiferent from and improved over the prior art products which can be held at only about 25% of the tension allowed by utilizing the teaching of the present invention.

Although I have described my invention with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.

What is claimed is:

1. In an apparatus for handling a moving continuous filament tow including a draw machine, a stuffer box crimper having a crimper chamber, and pull rolls operatively arranged to advance the tow to the crimper, the improvement of which comprises a roller convergence guide arrangement operatively mounted between the draw machine and the pull rolls to converge and shape the tow into a substantially rectangular cross section having a width corresponding to about the crimper chamber width, said arrangement comprising a pair of elongated cylindrical rollers vertically mounted on each side of the tow path and spaced apart a distance about equal to the crimper chamber width and at least four flanged elongated cylindrical rollers horizontally mounted in the tow path having substantially parallel longitudinal axes, said horizontal rollers being mounted between the vertical rollers and the pull rolls with said horizontal rollers further being disposed so that thetow path must traverse about 25% to about of the circumference of each horizontal roller, the distance between the flanges corresponding to about the crimper chamber width.

2. Apparatus as in claim 1 wherein the distance between the tow contacting surfaces of the opposed vertical rollers is within the range of about 0.125 inch to about 0.375 inch less than the distance between the flanges on the horizontal rollers.

3. Apparatus as in claim 1 wherein the crimper chamber width is within the range of about 1.5 inches to about 7 inches.

4. Apparatus as in claim 1 wherein said horizontal and vertical rollers are freely rotatable substantially frictionless rollers.

Refereuces Cited UNITED STATES PATENTS 2,311,174 2/1943 Hitt 28-72 3,218,675 11/1965 Hendrix l966 3,220,083 11/1965 Crawford et al 281 3,231,958 2/1966 Chadwick 28--1 3,248,103 4/1966 Tarbell l965 FOREIGN PATENTS 962,516 7/ 1964 Great Britain.

MERVIN STEIN, Primary Examiner. IRA C. WADDEY, JR., Assistant Examiner.

US. Cl. X.R. l966