US3887971A - Outlet means in a thermoplastic yarn rebound texturizing apparatus - Google Patents

Abstract

In a bounce crimping apparatus for texturizing multi-filament thermoplastic yarn including a yarn texturizing chamber, a means for introducing heated fluid into the yarn texturizing chamber for drawing yarn into the chamber, a foraminous surface transversely positioned across a longitudinal fluid outlet of the yarn texturizing chamber and a means for collecting texturized yarn in a condition substantially free from longitudinal tension; the improvement comprising means connected to a lateral outlet of the yarn texturizing chamber for conveying texturized yarn from the chamber and for compacting the yarn as the yarn moves to the means for collecting the texturized yarn.

Description

United States Patent 91 Guenther 1 1 OUTLET MEANS [N A THERMOPLASTIC YARN REBOUND TEXTURIZING APPARATUS [75] Inventor: Lloyd M. Guenther, Severna Park,

Chevron Research Company, San Francisco, Calif.

[22] Filed: Dec. 28, 1973 [21] App]. No.: 429,058

[73] Assignee:

[ June 10, 1975 3.665.567 5/1972 Clarkson M 28/14 1778.872 12/1973 Newton 28/111 $780,405 12/1973 lzawa ct al 28/111 Primary Examiner-Louis K Rimrodt Attorney, Agent, or Firm-G. F. Magdehurger; .l. Stoner, .lr.; .l. A. Buchanan, Jr.

[57] ABSTRACT In a bounce crimping apparatus for texturizing multifilament thermoplastic yarn including a yarn texturizing chamber, a means for introducing heated fluid into the yarn texturizing chamber for drawing yarn into the chamber, a foraminous surface transversely positioned across a longitudinal fluid outlet of the yarn texturizing chamber and a means for collecting texturized yarn in a condition substantially free from longitudinal tension; the improvement comprising means connected to a lateral outlet of the yarn texturizing chamber for conveying texturized yarn from the chamber and for compacting the yarn as the yarn moves to the means for collecting the texturized yarn.

3 Claims, 4 Drawing Figures OUTLET MEANS IN A THERMOPLASTIC YARN REBOUND TEXTURIZING APPARATUS BACKGROUND OF THE INVENTION This invention relates to an apparatus for texturizing synthetic thermoplastic yarn. More specifically, the in vention relates to an improved apparatus for bounce crimping thermoplastic yarn.

Synthetic thermoplastic yarn materials, as produced, are composed of continuous, straight, smooth filaments. Such yarns have little bulk, and their utility in textile applications is rather limited.

In order to enhance the bulk and texture of synthetic yarns, a variety of crimping processes have been used in the past. For thermoplastic yarns, a basic technique is to bend the yarn filaments and heat the yarn while the filaments are in bent or crimped configurations.

Recently, a basic advance has been achieved in texturizing thermoplastic yarn. This texturizing technique, known as a rebound or bounce crimping process, yields strikingly improved results as far as crimp quality is concerned.

Bounce crimping entails hurling yarn, by a heated fluid, through a jet in a continuous stream-like flow against a foraminous surface upon which the yarn impinges and from which the yarn instantaneously rebounds or bounces. The impact of the yarn upon the foraminous surface axially buckles and crimps individual filaments of the yarn while the heated fluid passes through the foraminous surface. The texturized yarn progresses without tension and substantially by rebound inertia away from the crimping zone and is guided to a collection station where the yarn is heated and then cooled to heat set the crimp prior to winding upon a storage spool.

Thermoplastic yarn texturized by the foregoing bounce crimping process possesses, inter alia, exceptional covering capability and a high degree of resiliency as disclosed in Miller et al. US. Pat. No. 3,686,848 issued Aug. 29, l972.

The basic process and apparatus for practicing the process is featured in Clarkson US. Pat. No. 3,665,567 issued May 30, 1972. In brief summary, the Clarkson structure entails feeding a yarn through an elongate slender tube by a jet of steam and hurling the yarn longitudinally against a foraminous screen. The yarn is thereby crimped or texturized and freely rebounds laterally through a passage from which it drops down to a receiver for heat setting. The steam primarily passes through the foraminous screen and is collected although at least some of the steam whistles or hisses laterally through the tubular passage along with the texturized yarn. In the event yarn becomes entangled upon the screen or within the outlet passage, a slit is provided in the lowermost portion of the laterally extending passage to permit a pair of underlying nip rollers to engage and extricate the yarn.

Notwithstanding singular advantages provided the synthetic textile industry by the above-noted Clarkson bounce crimping process and apparatus, room for significant improvement remains. One area of particular concern from the standpoint of actual commercial yarn manufacturing operations has been a degree of irregularity, or lack of uniformity, in the yarns produced through use of the bounce crimp process. Although the mechanically severe conditions in the crimp-producing zone are desirable as far as imparting good crimp charucteristics to the individual filaments of the yarn is concerned, these severe conditions tend to create wide variations in the assembly of filaments, that is, variations in the yarn body made up of the multitude of individually crimped filaments.

This point can perhaps be appreciated most easily by visualizing the situation near the foraminous member of a bounce crimp chamber during the processing of a typical upholstery yarn made up of say one hundred or more individual filaments. The jet hurls the filaments endwise against the foraminous member where they buckle in a somewhat random manner and bounce away in a random array. This array is a loose, fluffy, body which tends to conform generally in contour to the shape of the outlet opening from the crimp chamber and which varies in density along its length. In the apparatus known prior to this invention, a guide tube of rather large area, as compared with the area of the crimp chamber outlet, received the fluffy yarn and established its general direction of movement away from the crimp zone. However, this large diameter guide tube permitted the yarn to buckle back and forth upon itself to a substantial extent and afforded opportunities for protruding filaments at one portion along the yarn length to become entangled with filaments at another portion along the length of the yarn, thereby introducing still further irregularities.

A swingable flapper at the outlet of the guide tube of the heretofore known apparatus provided some control over the yarn issuing therefrom, but the control effect was limited primarily to preventing the yarn from rebounding too far laterally and missing the collector tube into which it was supposed to fall. In ordinary operation, the flapper swung back and forth unpredictably in response to pressure gusts. That is, rebounding yarn impacting against the flapper would set it in mo tion in a passageopening direction, such motion would reduce the capability of the flapper to restrain movement of the yarn, and an erratic oscillation system would be established. Although this arrangement had some tendency to consolidate the fluffy yam from the crimping zone, the consolidation effect was far from uniform along the length of the yarn.

Wide density variations along the length of a filament yarn in a tensionless state might safely be ignored in many instances because of the fact that these variations tend to be eliminated automatically when the yarn is tensioned. However, in the bounce crimp process, the yarn from the crimping zone is kept in the essentially tensionless state until after it has been subjected to heating and cooling cycles which serve to permanently set the thermoplastic filaments in their distorted shapes. That is, the wide variations tend to become permanent characteristics of the yarns and may show up as unintended and uncontrolled visual irregularities in products fabricated from the yarn.

Accordingly it would be highly desirable to provide a bounce crimping apparatus wherein the yarn would be subjected to controlled axial compaction immediately downstream from the crimping chamber to reduce its fluffiness and enhance the uniformity of the yarn density characteristics along the length of the yarn. Further, it would be highly desirable to reduce the tendency for knotting or tangles to occur within an outlet passage of the texturizing apparatus.

Still further, it would be desirable to eliminate the previously noted nip roller structure while maintaining a means for removing filaments which may occasionally be embedded or entangled within the texturizing screen. Yet additionally. it would be desirable to reduce noise pollution generated by the bounce crimping process.

OBJECTS AND BRIEF SUMMARY OF THE INVENTION Objects In light of the foregoing, it is a general object of the invention to provide an improved yarn rebound texturizing apparatus which will obviate or minimize deficiencies and provide enhanced properties of the type previously described.

It is a particular object of the invention to provide an improved bounce crimping apparatus wherein uniformity of the texturized yarn may be maximized.

It is another object of the invention to provide an improved outlet means for a bounce crimping apparatus wherein axial compaction of the yarn may be effected downstream from a bounce crimping chamber.

It is yet another object of the invention to provide an improved outlet for a bounce crimping apparatus wherein a smooth transition from a bounce crimping chamber to an outlet conduit is achieved in a manner which will facilitate axial compaction of the yarn and minimize lateral buckling of the yarn within the outlet conduit.

It is a further object of the invention to provide an improved outlet means for a yarn crimping chamber wherein tangles upon a foraminous bounce crimping surface may be effectively removed without the provision of previously utilized nipping rollers.

It is still a further object of the invention to provide an improved outlet means for a bounce crimping apparatus which will obviate or minimize noise pollution previously associated with bounce crimping operations.

Brief Summary A bounce crimping apparatus according to a preferred embodiment of the invention intended to achieve at least some of the foregoing objects includes a yarn crimping chamber provided with a foraminous surface or screen against which the thermoplastic filaments are impacted and an outlet through which the yarn bounces away from the screen, a yarn outlet tube connected to the crimping chamber outlet, and a means for receiving the yarn from the outlet tube and heat setting it in a condition substantially free from tension. The yarn outlet tube of the subject invention is preferably circular in cross section and smoothly mates with the outlet of the crimping chamber at one end for receiving texturized yarn. The internal cross sectional area of the tube is no greater than about twice that of the crimping chamber outlet so as to minimize buckling of the yarn back and forth upon itself as it moves through the tube. The tube is further fashioned with a bend to provide generally uniform axial resistance to the passage of yarn therethrough, thus effecting axial compaction of the yarn. This axial compaction is facilitated in one embodiment by the provision of a leaf spring extending within the outlet tube passage near its outlet end. The tube should have a substantial length (at least 3 and preferably times its diameter) to firm up the compacted yarn in the form of a loose plug, and it should not be open to atmosphere near its inlet end lest escaping steam in this area result in excessive noise and entanglement of loose filaments with edge portions of the opening.

THE DRAWINGS Further objects and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a front elevational view, partially broken away, of a bounce crimping apparatus for texturizing synthetic thermoplastic continuous filament yarns;

FIG. 2 is a cross sectional view taken along section line 2-2 in FIG. 1 and discloses a bounce crimping chamber and an improved lateral outlet tube according to a preferred embodiment of the invention;

FIG. 3 is a cross sectional view taken along section line 33 in FIG. 2 and discloses the cylindrical character of the improved outlet tube and the smooth transition from the bounce crimping chamber to the outlet tube; and

FIG. 4 is a bottom view of the improved outlet tube and specifically discloses a retaining mechanism for maintaining axial compression of the yarn within the outlet tube.

DETAILED DESCRIPTION Basic Structure of the Invention The improvement of the subject invention is in spe cific combination with a bounce crimping apparatus according to the above referenced Clarkson US. Pat. No. 3,665,567. The entire disclosure of this Clarkson patent is hereby incorporated by reference as though set forth at length. Briefly, however, the basic bounce crimping structure of the subject combination invention may be appreciated by reference to FIG. 1 which discloses an elevational view, partially broken away, of a bounce crimping apparatus 10.

A multifilament synthetic thermoplastic yarn 12 is fed from a supply package (not shown) to a first driven godet roll 16 with skewed separator roll 14 and then to a second driven godet roll 20 with skewed separator roll 18. Godet rolls 16 and 20 may be heated and rolls l8 and 20 advance the yarn at a much greater speed than do rolls 14 and 16 so that the yarn 12 is drawn between the two sets of rolls.

From roll 18 the yarn l2 advances to a yarn texturizing station indicated generally by reference character 22 and then into a heating chamber 24 where the yarn is heated in a loose mass substantially free from tension. The yarn passes downstream of the heating chamber 24 into a cooling chamber 26 where the yarn is cooled again in a loose mass substantially free from tension. The yarn 12 is then drawn from the cooling cham ber 26 in the form ofa strand over idler rolls 27, 28 and 29 by a pair of rolls 32 and 34. From godet roll 32 the yarn 12 advances over idler roll 36 to a standard takeup mechanism where the yarn is wound in a package 38 for storage and shipment.

Referring to FIG. 2 the yarn texturizing station 22 includes a yarn tube 40 which passes through a steam plenum chamber 42 formed by a plumbing tee 44, (FIG. I). The plumbing tee 44 is connected through a steam valve 46 to a steam pipe 48 so that steam may be fed to the plenum chamber 42 as regulated by valve 46.

The tube 40 passes completely through steam plenum chamber 42 and terminates at the upper end of a yarn passage chamber 50. The steam plenum chamber 42 fiuidically communicates with yarn passage chamber 50 so that steam from the plenum chamber may pass downwardly about tube 40 and into the annular space between tube 40 and an upward continuation of the walls defining the yarn passage chamber 50. The tube 40 is held in a coaxial posture with respect to the yarn passage chamber 50 by means of struts 52 on the lower end of the yarn tube 40.

Steam passes through the annular chamber and around the struts 52 to the yarn exit end of the tube 40 where the steam picks up the yarn l2 exiting from the tube 40 and hurls the yarn longitudinally through yarn passage chamber 50. As will be noted, yarn passage chamber 50 extends beneath the lower end of the tube 40 and is continued as a bore 54 in an adapter housing 56. The diameter of the bore 54 is the same as the internal diameter of the yarn passage chamber 50 so that a single diameter cylindrical passage is provided for the yarn as the yarn exits from tube 40 until it reaches the level of a yarn opening 60 within the side of the adapter housing 56.

The external lower end of the adapter housing 56 has a convex configuration surrounding the lower end of the bore 54. A member 62 having a foraminous surface, such as a screen, closes the lower end opening of the bore 54 to the passage of yarn while simultaneously permitting steam to longitudinally pass through the openings in the screen 62.

The adapter housing 56 is fitted with a coaxial collar 64 which serves as an adapter for connection of the bore 54 with a steam exhaust conduit 66. By the provision of the exhaust conduit, steam passing through screen 62 may be drawn off by a blower (not shown).

The above described components cooperate to texturize thermoplastic yarn introduced into tube 40 by the technique ofrebound" or bounce crimping. In this connection, thermoplastic yarn 12 is heated as it advances through the yarn tube 40 and is picked up by the steam at the exit end thereof. The plastic yarn is then hurled longitudinally with great force by the downward flow of steam toward the screen 62 at the centermost point of the concave portion of the screen. The bulk of the steam passes through screen 62, while the filaments of yarn 12 are intercepted thereby to be bent and crimped by the impact and then rebound or bounce from screen 62 instantaneously and in a continuously moving strand-like stream to flow upwardly and to the left into an improved conveying and compacting means 68. From the improved conveying and compacting means 68 the yarn is deposited into the heating chamber 24.

As noted in FIG. 1, the heating chamber 24 consists of an outer sleeve of insulation 70 which surrounds a steam chamber 72, which in turn encompasses an inner cylindrical yarn treating chamber 74. Steam is circulated through chamber 72 to heat the wall about the yarn treating chamber 74, and consequently to heat the yarn contained within the chamber 74.

The rebounded texturized yarn [2 falls into the yarn receiving chamber 74 in a condition substantially free of longitudinal tension. As the yarn 12 is withdrawn from the cooling chamber 26 by godet rolls 32 and 34, the loose mass of yarn within the heating chamber 24 progresses downwardly through the heating chamber.

To further assist in heating the yarn within chamber 74, hot air bleed tubes 76 are disposed vertically within the chamber 74 and are provided with apertures spaced at regular intervals throughout the longitudinal extent thereof. Air heated in the steam chamber 72 is blown from the apertures within bleed tubes 76 into chamber 74 to circulate through the mass of yarn within the chamber 74 and insure uniform heating of the texturized yarn.

As previously noted, immediately beneath the heating chamber 24 there is disposed a cooling chamber 26 comprising the bottom leg of a J-tube formed by the heating chamber 24 and the cooling chamber 26. The yarn passes through the cooling chamber 26 still in a loose untensioned mass. To assist in cooling the yarn, two air bleed tubes 78 are disposed inside and on opposite sides of the cooling chamber 26. Air at room temperature is blown through the cooling tubes 78 and out through apertures within the tubes along the longitudinal length thereof to circulate through the yarn mass to cool the yarn and exit through an opening 80 within a top portion of the cooling chamber 26.

Not until this point when the yarn has been fully heat set and cooled is the texturized yarn subject to longitudinal tension. As noted in FIG. 1, the yarn 12 is now withdrawn from the cooling chamber 26 over a baffle 82 and through an eyelet 84 which tends to remove gross tangles in the yarn. To further remove any persistant tangles a series of tension vanes 86, 88, and 92 are provided. These vanes are simply thin pieces of sheet metal shaped to close the chamber and pivot at hinges 94, 96, 98 and 100, respectively, so that gravity will pivot the tension vanes against a wall 102 of the chamber.

The yarn thus untangled advances in a substantially linear form over idler rolls 27, 28 and 29 by pull-out godet rolls 32 and 34 to be wound upon a package 38 in a conventional manner as previously noted.

IMPROVED OUTLET AND COMPACTION ASPECT OF THE INVENTION As specifically illustrated in FIGS. 24 an improved outlet and compaction means 68 in combination with a bounce crimping apparatus, according to a preferred embodiment of the invention, comprises a cylindrical tube 104 having a circular cross section and is designed to normally extend at a first end 105 into and mate with the adapter body 56. In this connection a central longitudinal axis of the tube 104 at the first end 105 will intersect and lie at right angles to the central longitudinal axis of the bore 54 of adapter 56. The other end 106 of the outlet tube is bent downwardly approximately 90 with respect to the first end such that the central longitudinal axis of the tube at the second end extends at a right angle with respect to the central longitudinal axis of the tube at the first end thereof.

As specifically illustrated in FIG. 3 the internal diameter of the circular tube 104 is slightly greater than an arcuate upper surface 107 of a lateral outlet arch 108 fashioned within the adapter 56. Accordingly, texturized yarn filaments rebounding from the foraminous surface 62 smoothly enter the outlet tube 104 without becoming tangled by sharp edges or comers between the outlet tube 104 and the adapter housing 56. This smooth transition zone minimizes the occurrence of a blocking or jamming tendency of the texturized yarn at the outlet of the adapter 56.

Moreover, it will be noted from FIG. 3 that the internal cross sectional area of the tube 104 is not vastly greater than that of the adapter yarn outlet opening defined by the screen 62 at the bottom and the arch 108 at the top. This feature is important in that it has been found desirable to inhibit buckling of the yarn back and forth upon itself as the yarn moves along the tube 104. The loose. fluffy, yarn from the crimping zone tends to assume the general size and shape of the adapter outlet opening. and if this is very much smaller than the pas sage into which the yarn is moving there is a tendency for buckling along the length of the yarn to cause yarn to eject intermittently and to produce irregularities in the product. It has been found, in accordance with the invention, that such difficulties may be avoided if the internal cross sectional area of the tube 104 is in the range of from about 1 /2 to about 2 times the area of the adapter outlet opening. Under these conditions, there is little tendency for lateral buckling of the yarn; instead it may compress axially to substantially fill the cross sectional area of the tube 104 so that reshaping of the filament assembly takes place smoothly and regularly.

The arcuate, approximately 90, bend in the outlet tube 104 provides resistance to the passage of texturized yarn through the tube. in this connection, as the yarn encounters increased resistance provided by the curve in outlet tube 104, the yarn increases in axial compaction as schematically represented at points 110, 112 and 114. The length of the tube 104 should be in excess of 3 and at least 5 times its diameter, so that the compaction may take place over a zone of substantial length. The outlet tube 104 progressively imparts axial compaction to the texturized yarn to provide a loose plug of individually crimped fibers. This axial compres sion downstream of the crimping chamber facilitates the overall yarn texturizing process.

This advantageous axial compression of the texturized yarn within the outlet tube may be enhanced yet further by the provision of back pressure apparatus 116 positioned adjacent the outlet end of the tube 104. More particularly, the tube 104 may be fashioned with an oblong opening or slot 118 in the surface thereof for permitting the entrance of a leaf spring 120. The spring 120 is mounted upon the tube 104 by a mounting collar 122 and set screw 124.

The leaf spring 120 extends within the tube 104 substantially across the axial passageway thereof and facilitates the back pressure maintaining character of the outlet tube as initially provided by the arcuate configuration thereof. The back pressure provided by leaf spring 120 further adds axial compaction to the yarn as it progresses in a loose mass through the outlet tube 104 and falls into the heat treating chamber 24.

The presence of the spring 120 is particularly advantageous from the standpoint of enhancing the versatility of the apparatus. Where different sizes of yarns are to be processed. the resistance to movement offered by the bent tube alone may vary significantly in dependence upon the size of the yarn, but the spring 120 tends to make reasonably uniform the overall resistance to passage of the yarns. The spring is very light in weight, so that its inertia characteristics do not contribute significantly toward the production of nonuniformities in the yarn being processed.

The spring force exerted by the spring 120 preferably is small. its primary function is to assure the presence of sufficient resistance to prevent unimpeded flow of yarn out of the tube, and this can be accomplished with a light force. it is in fact undesirable to impose large back pressures on the yarn outlet. When the back pressure becomes unduly large, the free exit of the filaments from the crimping zone is impeded and there is a tendency for some of them to stay in contact with the hot steam stream long enough to fuse slightly and adhere to one another. The development of such an undesirable situation is readily detectable through examination of the yarn issuing from the outlet tube, and when such a situation does develop, it can be corrected easily by bending the spring a little to reduce its impeding force on the yarn.

In addition to the already noted advantages associated with the gradual increase in axial compaction of the yarn within the outlet tube, the loose mass of yarn filaments compressed within the outlet tube serve as a muffler or noise barrier, and hissing or whistling noises generated by the steam jet are attenuated. In this connection, in prior bounce crimping devices, noise from the steam jet could readily exit through the yarn outlet passage and presented a highly undesirable noise pollution at the crimping apparatus which made working conditions around the apparatus irritating and objectionable.

A further synergistic function of the outlet tube 104 is achieved by its capacity to free yarn filaments which become lodged within the foraminous screen 62. More particularly, in some instances, individual yarn filaments tend to stick or become lodged in the openings within the foraminous member 62 and thus not rebound into the outlet tube as desired. As noted in the background of the invention, nip rollers have been previously provided to correct such errant operation. With the provision of the subject improved outlet tubular member, however, not only is texturizing facilitated by axially compacting the yarn as the yarn passes from the texturizing chamber to a heat treating chamber, but the plug of advancing texturized yarn formed within the outlet tube 104 serves as a mass to pull upon and thus free individual yarn filaments which occasionally become embedded within the foraminous surface 62.

SUMMARY OF MAJOR ADVANTAGES In describing a preferred embodiment of an improved outlet tube structure in combination with a bounce crimping apparatus, several highly advantageous aspects of the invention have been delineated.

in brief summary, the curved outlet tube 104 provides an increasing axial compaction upon the yarn within the tube without reversely bending the yarn and thus facilitates the overall texturizing process. Further, the transition of a loose axially compressed plug of crimped filaments conforming to the shape of the outlet 108 within the adapter 56 into a circular bundle in the outlet tube without permitting axial yarn buckling minimizes the formation of irregularities during the texturizing process.

Progressive axial compaction of the yarn through the outlet tube is facilitated by a leaf spring positioned adjacent the outlet end of the tube 104.

Synergistically with the foregoing noted improvements in the texturizing process, noise pollution from process steam is substantially reduced by the loose plug of axially compressed yam filaments within the outlet tube. In a similar vein, the moving plug of yarn filaments serves as a means for removing individual filaments which may occasionally become embedded within the foraminous crimping screen 62.

While the invention has been described with reference to preferred embodiments, it will be appreciated by those skilled in the art that additions, deletions. modifications and substitutions or other changes not specifically described may be made which will fall within the purview of the appended claims.

What is claimed is:

I. In bounce crimping apparatus for cxturizing multi-filament thermoplastic yarn including:

a yarn texturizing chamber having an inlet, a fluid outlet aligned longitudinally with said inlet, and a lateral yarn outlet,

means for introducing a heated fluid into said yarn texturizing chamber for drawing yarn into said chamber,

a foraminous surface positioned across said fluid outlet of said chamber, said heated fluid introduced into said chamber for drawing yarn into said chamber further serving to hurl the yarn against said foraminous surface to axially compress and crimp the yarn filaments and rebound the yarn through said lateral outlet, and

means for collecting the crimped yarn while main taining the yarn substantially free from longitudinal tension.

the improvement comprising:

a tubular member connected to said lateral outlet in said chamber for conveying the crimped yarn from said chamber to said means for collecting the crimped yarn and for continuously axially compacting the yarn as the yarn is conveyed to said means for collection,

said tubular member having,

a first end connected to said lateral outlet of said chamber for receiving yarn rebounded from said foraminous surface, wherein a central longitudinal axis of said tubular member at said first end extends at right angles with respect to and intersects a central longitudinal axis of said chamber,

and a second end for directing the yarn from the tubular member into said means for collecting the crimped yarn, said tubular member being curved such that said curve provides resistance to the passage of yarn therethrough for axially compacting the yarn within the tubular member, and said tubular member being circular in cross section and having an inside diameter slightly greater than the largest dimension of said lateral outlet of said yarn texturizing chamber whereby yarn hurled against said foraminous surface to be axially com pressed and crimped and rebound through said lateral outlet may readily enter said tubular member and conform to the shape thereof without substantial buckling of the yarn upon itself as said yarn exits said lateral outlet. 2. A bounce crimping apparatus for texturizing multifilament thermoplastic yarn as defined in claim 1,

wherein said means for conveying and axially compacting comprises:

a tubular member having an internal cross sectional area in the range of from about one and one-half to about two times the area of said lateral outlet.

3. A bounce crimping apparatus for texturizing multifilament thermoplastic yarn as defined in claim 1 wherein the improvement further comprises:

member.

Claims (3)

1. In bounce crimping apparatus for texturizing multi-filament thermoplastic yarn including: a yarn texturizing chamber having an inlet, a fluid outlet aligned longitudinally with said inlet, and a lateral yarn outlet, means for introducing a heated fluid into said yarn texturizing chamber for drawing yarn into said chamber, a foraminous surface positioned across said fluid outlet of said chamber, said heated fluid introduced into said chamber for drawing yarn into said chamber further serving to hurl the yarn against said foraminous surface to axially compress and crimp the yarn filaments and rebound the yarn through said lateral outlet, and means for collecting the crimped yarn while maintaining the yarn substantially free from longitudinal tension, the improvement comprising: a tubular member connected to said lateral outlet in said chamber for conveying the crimped yarn from said chamber to said means for collecting the crimped yarn and for continuously axially compacting the yarn as the yarn is conveyed to said means for collection, said tubular member having, a first end connected to said lateral outlet of said chamber for receiving yarn rebounded from said foraminous surface, wherein a central longitudinal axis of said tubular member at said first end extends at right angles with respect to and intersects a central longitudinal axis of said chamber, and a second end for directing the yarn from the tubular member into said means for collecting the crimped yarn, said tubular member being curved such that said curve provides resistance to the passage of yarn therethrough for axially compacting the yarn within the tubular member, and said tubular member being circular in cross section and having an inside diameter slightly greater than the largest dimension of said lateral outlet of said yarn texturizing chamber whereby yarn hurled against said foraminous surface to be axially compressed and crimped and rebound through said lateral outlet may readily enter said tubular member and conform to the shape thereof without substantial buckling of the yarn upon itself as said yarn exits said lateral outlet.

2. A bounce crimping apparatus for texturizing multi-filament thermoplastic yarn as defined in claim 1, wherein said means for conveying and axially compacting comprises: a tubular member having an internal cross sectional area in the range of from about one and one-half to about two times the area of said lateral outlet.

3. A bounce crimping apparatus for texturizing multi-filament thermoplastic yarn as defined in claim 1 wherein the improvement further comprises: said tubular member being operatively curved downwardly and having an opening formed in the surface adjacent the second end thereof; and leaf spring means connected to said tubular member adjacent said opening and extending through said opening into said tubular member for partially blocking the passage of crimped yarn through said tubular member to facilitate axial compaction of the yarn during its passage through said tubular member.

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