US3696467A - Process and apparatus for producing yarn - Google Patents

Abstract

Process and apparatus for converting a tow composed of a multiplicity of substantially continuous synthetic textile filaments into a sliver or strands of staple length textile fibers by stretch breaking the tow. The tow is evened and portions of the filaments are differentially laterally deflected. The apparatus includes movable deflecting blades in rotating blade holders, said blades having a contour to provide peaks and valleys and a second set of movable blades in rotating blade holders, said blades having straight edges. The blade holders rotate so that the blades of each alternate in engagement with the tow.

Description

United States Patent Lohrke, Jr.

[ 51 Oct. 10,1972

[54] PROCESS AND APPARATUS FOR PRODUCING YARN [72] Inventor: James L. Lohrke, Jr., Birmingham Township, Chester City, Pa.

[73] Assignee: Turbo Machine Company [22] Filed: Dec. 14, 1970 [21] Appl. No.: 98,209

Related US. Application Data [63] Continuation-impart of Ser. No. 794,238, Jan.

27, 1969, abandoned.

52 us. Cl ..19/.37 51 Int Cl. ..D01g 1/00 [58] Field of Search ..19/.3, .64, 65 T, 66 T [56] References Cited UNITED STATES PATENTS 3,500,504 3/1970 Oguchi et a1. l9/.37

Primary Examiner-Dorsey Newton Att0rneyPaul & Paul [57] ABSTRACT Process and apparatus for converting a tow composed of a multiplicity of substantially continuous synthetic textile filaments into a sliver or strands of staple length textile fibers by stretch breaking the tow. The tow is evened and portions of the filaments are differentially laterally deflected. The apparatus includes movable deflecting blades in rotating blade holders, said blades having a contour to provide peaks and valleys and a second set of movable blades in rotating blade holders, said blades having straight edges. The blade hol ders rotate so that the blades of each alternate in en gagement with the tow.

5 Claims, 5 Drawing figures PROCESS AND APPARATUS FOR PRODUCING YARN CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of my prior copending application Ser. No. 794,238, filed Jan. 24, 1969, now abandoned, for Process and Apparatus for Producing Yarn, and discloses and claims in part the subject matter disclosed and claimed in that application.

BACKGROUND OF THE INVENTION This invention relates to a process and apparatus for converting a tow composed of a multiplicity of substantially continuous synthetic textile filaments into a sliver or strands of staple length textile fibers.

In US. Pat. No. 1,883,384, granted to James Louis Lohrke (Sr.) and Henry H. Perry on Oct. 18, 1932, there is disclosed a process for the continuous conversion of tow of continuous textile filaments into sliver and/or yarn, by subjecting the-filaments to a tensioning action or drafting, thereby breaking the individual filaments into staple length fibers, but, at the same time, preserving their relative parallelism.

U.S. Pat. No. 2,419,320, granted to James Louis Lohrke (Sr.) on April 22, 1947, disclosed an improvement in the continuous conversion of tow into staple length sliver by drafting and subjecting the tow to an intermittent transverse deflection action out of its normal path. Such action of deflecting the tow out of its normal path intermittently, resulted in improved control over fiber length in comparison to the pure stretch breaking earlier disclosed in US. Pat. No. 1,883,384 where no deflection device was used.

The process of US. Pat. No. 2,419,320 has become commercially accepted and is one of the major means of converting synthetic fiber tows into slivers for spinning into yarns. One textile machine using this principle is the Turbo Stapler, manufactured by the Turbo Machine Company of Lansdale, Pa. Textile mills throughout the world have purchased the Turbo Stapler primarily for the continuous conversion of acrylic tows into sliver by stretch breaking for spinning into yarns for the knitting trades.

Practical textile mill experience has shown that the process as described in US. Patent No. 2,419,320 and utilized by the Turbo Stapler is highly critical in respect to the levelness of the tow entering the stapler. Generally, it is ideal to have the tow sheet of a uniform thickness of 15 fibers in height. However, it has so far not been possible for the synthetic fiber producers to manufacture commercially a tow of uniform thickness. Commercially manufactured tow will normally have sections with as few as fibers in height, or less, and other sections with as many as 30 fibers or more. This large variation in the number of fibers in height in the tow sheet results in a variation in the effect from the deflecting devices and this, in turn, results in a loss of variation of the effect of the deflection devices between the thin sections where the deflecting devices act more or less directly on individual fibers, and .the thick sections, where the deflecting devices canact only'on the fibers near the top of or near the bottom of the tow sheet. Those fibers within the center of the tow sheet are more or less shielded from the deflection action by the outer fibers. There is no substantial realignment of the distribution of the longitudinally extending fibers-across the width of the two band.

In US Pat. No. 3,500,504 a further method of producing sliver directly from tow is disclosed. The

sliverproduced by this method includes a large portion of cut fibers. The patentee sets forth what he considers to be hisimprovement over the standard Turbo stretch breaker and the well known deflecting stretch breaker, emphasizing the fact that his improvement consists of cutting the fibers and that the larger the amount of cut fibers in the tow as it passes through the breaking zone, the smaller is the breaking force required in the system.

In actual practice, the device in accordance with this SUMMARY OF THE INVENTION The present invention is an improvement both in process and apparatus over the deflecting devices earlier shown and embodies the feature that all fibers can be subjected to direct deflection, even though they be within a fairly thick section of the tow sheet. Therefore, thick sections of the tow sheet are acted upon more or less in the same manner as thin sections. Further, it is possible to process tow sheets with a thickness greatly in excess of 15 fibers in height, while at the same time preserving control of the length of the fibers produced.

The present invention is directed specifically to an improved process of and apparatus for stretch breaking tow. The fibers of the tow sheet are subjected not only to transverse deflection, but also to lateral deflection. The distribution of filaments in the tow sheet is evened by a process in which the filaments are separated into bundles and alternately returned to a more homogeneous mass prior to reseparation. The evening process and lateral deflection process take place across a substantially flat bar which coacts with the tow band to flatten and spread the bundles and differentially deflect them laterally thereby impressing stresses at different points within the bundles as they are presented in the device for stretch breaking.

The primary object of the present invention is to improve the known methods of stretch breaking tow.

Another object is to provide an improved tow deflecting device in a stretch breaking apparatus for processing the currently available, substantially nonuniform tow.

A further object of the present invention is the improvement in control over staple fiber length over present tow deflecting devices with any given quality of tow sheet levelness.

Other objects and advantageous features of the invention will be apparent from the following description and claims.

BRIEF DESCRIPTION OF THE DRAWINGS The nature and characteristic features of the invention will be more readily understood from the following description taken in connection with the accompanying drawings forming part thereof in which:

FIG. 1 is a schematic elevation of apparatus tostretch break tow into staple length sliver utilizing the present invention;

FIG. 2 is an enlarged transverse sectional view, taken approximately on the line 22 of FIG. 1;

FIG. 3 is a sectional view, taken approximately on the line 3-3 of FIG. 2;

FIG. 4 is a fragmentary view of a portion of a modified form of deflecting blade; and

FIG. 5 is a diagrammatic view showing a modified form employing a different number of blades in the blade holder.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now more particularly to FIG. 1, there is shown an apparatus for stretch breaking tow of continuous filaments of synthetic fibers into staple length fibers in sliver form.

Driven rollers and 11 are provided to draw the tow 12 into the machine. The tow 12 then passes to and between driven rollers 14 and 15 which tension the tow 12, or when required stretch the tow 12, in the presence of heat if desired, to reduce the diameter of the filaments. The tow 12 then passes to and between driven rollers 16 and 17, which have a higher surface speed than the roller pair 14, 15 causing a further tension to be applied to the fibers.

lnterposed between the roller pair 14, 15 and the roller pair 16, 17, the deflecting device 20 to accomplish the desired deflection is provided.

The deflecting device 20 preferably includes a pair of blade holders 21 and 22, shown in more detail in FIGS. 2 and 3, secured to drive shafts 23 and 24; gears 25 and 26 being provided for rotating the shafts 23 and 24 and the blade holders 21 and 22 in unison.

One of the blade holders, such as the blade holder 21, is provided with a plurality of blades 30 having along their exposed edges a configuration to provide spaced peaks 31 and valleys 32. One preferred edge profile for this purpose is composed of straight meeting edges 33 and 34 with apexes at the peaks 31 providing a saw tooth.

Other blade profiles could be employed such as that shown in FIG. 4 in which a blade 36 is illustrated having a sinuous profile with peaks at 37 and valleys at 38.

The blades 30, as shown in FIG. 2, are mounted in the blade holder 21 so that the respective peaks 31 and valleys 32 are offset or staggered. As illustrated, the peaks 31 on successive blades are each advanced laterally one quarter of or distance between the peaks 31. Between the blades 30 on the blade holder 21 there are clearance grooves 39 with a depth about two thirds the depth of the blades 30.

The other blade holder 22 has a plurality of blades 40 with straight edges 41. The blade holder 22 has clearance grooves 39 between the blades 40 like those of the blade holder 21. The blades 40, just as the blades 30, are designed to extend across the full width of the tow band and beyond both edges thereof.

As the tow sheet 12 is advanced first by the rollers 10, 11 then by the rollers 14, 15 with tensioning, and further advanced with further tensioning by the rollers 16 and 17, the fibers are subjected to the action of the deflecting device which is arranged as clearly illustrated in FIG. 1 in a similar fashion to the Lohrke US. Pat. No. 2,419,320, so that the blades on the rotating blade holders deflect the tow vertically, that is, transversely from its normal path of travel. In addition, because of the particular blade configuration and arrangement of blades in accordance with this invention the tow is evened and differentially deflected laterally, that is, across the width of the band.

As each blade 30 advances to the tow sheet 12, the peaks 31 penetrate the sheet and the edges of the teeth deflect the filaments laterally from their normal path and also separate them into bundles or groups of filaments. As the next blade 30 advances its peaks 31 penetrate the tow sheet 12, but at different locations offset from the previous areas of penetration. Since the blades and blade holders are arranged so that the blades 30 alternate with the blades 40 in engaging the tow, the next blade to engage the tow will be a straight edged blade 40. This will engage the tow from the opposite surface. This blade not only transversely, that is, vertically, deflects the tow sheet, but also, in coaction with the tow sheet itself, the individual filament bundles, and the blade 30, deflects the filaments laterally so that the filaments are drawn across the flat edge of the blade 40. The straight edges 41 of the blades 40 bring the tow sheet back to a relatively flat configuration in that they tend to flatten the bundles and spread them out so that they tend to come together once again in a more homogeneous mass. At the same time since the bundles comprise a plurality of filaments and since the filaments are spaced at various levels along the sloping surfaces of the teeth, these filaments are differentially subject to lateral drawing across the straight surface of the blade 40.

As the next blade 30 advances its peaks 31 penetrate the tow sheet 12, but at different locations offset from the previous areas of penetration. This occurs with each successive blade 30 because the sheet has been substantially flattened and returned to a more uniform configuration by the intermediate engagement of a blade 40 of the holder 22. This provides an improved redistribution of the filaments across the tow band, since there are not previously formed spaced apart bundles which would tend to preserve their integrity and move as a bundle into the next groove between the peaks. It must be remembered that the tow is a relatively flexible material and can bend quite easily even though it is being stretch broken. It is by no means a rigid material and its physical properties are such that it tends to remain as a cohesive group of fibers rather than falling apart or being easily separated. These stretch broken bundles of fibers, of course, can be pulled apart after passing through the machine.

By means of the above apparatus and method the fibers in the tow are subjected to different degrees of stretching laterally as different blades act upon them. The bundles of fibers do not tend to remain uniform cohesive groups, but rather are returned to a mass and then again reseparated; so that, in operation, the bundles do not preserve their integrity.

Referring now to FIG. 5 of the drawings, a modification is illustrated wherein blade holder 21 has eight blades 30 and the other blade holder 22' has seven blades 40 to distribute the wear. By using blade holders 21 and 22 which differ in the number of blades from one another by one blade, each saw- tooth blade 30 or 36 will eventually intersect betweenall pairs of straight blades 40, thereby evening out the wearing on the straight blades 40.

It will be understood that various changes in the details, materials and arrangement of parts which have been herein described and illustrated in order to explain the nature of this invention, may be made by those skilled in the art within the principle and scope of the invention as expressed in the following claims.

In particular, the blade configuration, the speed at which the device is run, and the type of material are all factors which will affect the performance of this device. These can be adjusted by one skilled in the art to provide the desirable end pattern by making use of the above disclosure of my invention. It is noted, in particular, that blades having smooth clean surfaces free from burrs or nicks are desirable, since such defects in the blade surface tend to grab and cut the fibers rather then allowing them to be continuously stretch broken.

It will further be understood that the Abstract of the Disclosure set forth above is intended to provide a non-legal technical statement of the contents of the disclosure in compliance with the Rules of Practice of the United States Patent Office, and is not intended to limit the scope of the invention described and claimed herein.

What is claimed is:

1. During the process of converting a continuous filament synthetic fiber tow into staple length sliver by stretch breaking, the improvement which comprises the steps of:

a. advancing the tow under tension;

b. deflecting the tow transversely and laterally and forming it into bundles;

c. flattening and spreading the bundles toward one another; and

d. then redividing the flattened spread bundles to even the tow while simultaneously differentially laterally deflecting and stretch breaking the tow filaments.

2. The invention of claim 1 wherein the individual filaments of the tow are differentially drawn across a flat surface.

3. An apparatus for converting a continuous filament synthetic fiber tow into a staple length sliver by stretch breaking, comprising:

a. a first set of draft rollers;

b. a second set of draft rollers for imparting a tension to the tow between said sets of rollers; and

c. a deflecting means between said sets of rollers for deflecting the filaments in the tow both transversely and laterally and for evening the tow as it is being stretch broken, said deflecting means comprising a pair of rotating blade holders each having a plurality of blades therein; the blades in one holder having free surfaces for engagement wj h the tow, said surfaces being curved so as to provi e peaks and valleys for engaging the face of said tow; the blades of the other blade holder having edges for engaging said tow which are straight; the holders being arranged to rotate so that the straight edged blades engage a face of the tow opposite from the face engaged by the blades on the other holder; the blades of one holder alternating with the blades of the other holder in engaging the tow.

4. The invention of claim 3 wherein one blade holder has more blades on it than the other blade holder.

5. The invention of claim 3 wherein the holders are so arranged with respect to one another and with respect to the tow that the individual fibers of the tow are differentially drawn laterally across the flat straight surfaces of the straight blades during stretch breaking.

* g;gg I UNITED STATES PATENT ()FFICE CERTIFICATE OF CORRECTIQN Patent No. 3,696,467 Dated OC CObel" 10', 1972 Inventor(s) James ohrke, Jr

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. l, Line 6 delete "24" and insert -27-- C01. 2, Line 10 delete "two" and insert --tow-- Col. 3, line 51 after "quarter of" insert --the pitch-- Signed and sealed this 27th day of March 1973.

(SEAL) Attest:

EDWARD M.PLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer Commissioner of Patents

Claims (5)

1. During the process of converting a continuous filament synthetic fiber tow into staple length sliver by stretch breaking, the improvement which comprises the steps of: a. advancing the tow under tension; b. deflecting the tow transversely and laterally and forming it into bundles; c. flattening and spreading the bundles toward one another; and d. then redividing the flattened spread bundles to even the tow while simultaneously differentially laterally deflecting and stretch breaking the tow filaments.

2. The invention of claim 1 wherein the individual filaments of the tow are differentially drawn across a flat surface.

3. An apparatus for converting a continuous filament synthetic fiber tow into a staple length sliver by stretch breaking, comprising: a. a first set of draft rollers; b. a second set of draft rollers for imparting a tension to the tow between said sets of rollers; and c. a deflecting means between said sets of rollers for deflecting the filaments in the tow both transversely and laterally and for evening the tow as it is being stretch broken, said deflecting means comprising a pair of rotating blade holders each having a plurality of blades therein; the blades in one holder having free surfaces for engagement with the tow, said surfaces being curved so as to provide peaks and valleys for engaging the face of said tow; the blades of the other blade holder having edges for engaging said tow which are straight; the holders being arranged to rotate so that the straight edged blades engage a face of the tow opposite from the face engaged by the blades on the other holder; the blades of one holder alternating with the blades of the other holder in engaging the tow.

4. The invention of claim 3 wherein one blade holder has more blades on it than the other blade holder.

5. The invention of claim 3 wherein the holders are so arranged with respect to one another and with respect to the tow that the individual fibers of the tow are differentially drawn laterally across the flat straight surfaces of the straight blades during stretch breaking.

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