US2635295A - Apparatus for converting tow to top - Google Patents

Description

April 21, 1953 R. H. DE LACOTTE ET AL 2,635,295

APPARATUS FOR CONVERTING TOW TO TOP 2 SHEETSSHEET 1 Filed Oct. 50, 1951 0 IO a0 IOOZ l'mncmors,

105f17 6 6/15 PEA/460771.

Gttomeg April 21, 1953 R. H. DE LACOTTE ET AL 2,635,295

APPARATUS FOR CONVERTING TOW TO TOP Filed Oct. 30, 1951 2 SHEETS-SHEET 2 7 Imnentors 1905597 flaw:- fiEL/ICUfff 3g [FNMA/V054 7275575 (Iltomeg Patented Apr. 21, 1953 UNITED STATE S. PATENT OFFICE APPARATUS FOR CONVERTING TOW TO TOP Robert Heme de Lacotte and Emmanuel Teissier,

Paris, France, assignors to Societe de Constructions Mecanique de France Stains, a corporation of Application October 30, 1951, Serial No. 253,872 In France August 23, 1951 This invention relates to a process and appara- 5 Claims. (C

tus for converting a bundle or tow of continuous filamentsinto a sliver or top of staple fibers, and .f more particularly to a method and apparatus in In systems of this type the length of the staple fibers produced corresponds in general to the spacing between the two sets of rolls although a considerable number of short fibers are also produced which impair the quality of the yarn spun therefrom. Long periodic irregularities are also observed which produce irregularities in thickness of the yarn formed by drafting and twisting the sliver or top.

The process that forms the subject matter of the present invention involves imposing upon the bundle while drawing to breakage a deviation from the straight path by means of a rotary member having pronounced but not cutting edges.

Through this procedure points of lowered resistance are momentarily created in the filaments tofbe broken as a result of the pronounced support and bending of the filaments by the projecting-edges. The projecting edges also produce an impact as well as a momentary change in tension and in the deflection from the normal path of the filament which causes the filaments to break at such points of lowered resistance.

The invention will be better understood byreferring to the following description, taken in connection with the accompanying drawings, in which specific embodiments are set forth for purposesof illustration.

in the drawings:

Fig; 1 is a diagrammatic view illustrating one 7 embodiment of the invention;

Fig. 2 is a curve showing the improvement in length of the staple;

Fig. 3 is a detail view of a band having dihedrals to be used in the embodiment of Fig. 1;

Fig. 4. is a diagrammatic view similar to Fig. 1; and

Fig. 4a. is a detail view of the band used in the embodiment of Fig. 4. y

In Fig. l a bundle of filaments 1, advancing in the direction of the arrows, is supplied'by a pair of feed rollers l, 2 and is pulled by the pair of stretch rollers 3, 4 revolving at a speed that is a multiple of the speed of the rollers I, 2. As a result of this the portion of the bundle 1 between rollers 2 and rollers 3, 4 undergoes a stretchingwhich causes a breakage of the filament. The filament is made to deviate from the straight path by contact with a member 5 revolving on an axis 6,,the edges of which member successively cause the filament to deviate with jerks. The breaks of filaments occur at the con- 50 tact or the edges which produce weak points.

2 There is used for example a sliver of 1500 deniers, 1500 filaments of regenerated cellulose, having a tenacity of 2.25 grs. per denier.

The rollers l, 2 have a peripheral speed of 90 ;cm./min., and the rollers, 3, 4 have a peripheral 1 speed of l3.5M/min., giving a stretching ratio of 15 and producing a spun yarn of 100 d. on the average.

Without interposition of the member 5 and ;with suitable twisting a spun yarn is produced that has a tenacity of 1.35 g/d., viz. of the The elongation V to break of the spun yarn is 4.5%. When this spun yarn is moistened and when drying is done tenacity of the initial bundle.

without tension a shrinkage of 9% is observed.

With the use of a member 5 of 20 mm. per side, having a speed of rotation of R. P. M., viz. a'i' peripheral speed of 5.2M/min., a spun yarn is ob tained that has a tenacity of 1.80 g/d/. or

-;of the tenacity of the initial bundle. The elongation to rupture or break is 6%. The shrinkage upon moistening followed by drying is 7%. The" irregularities of long period are practicallly absent and the length of the fibers is more regular ,and the very short fibers are reduced in number.

Since the staple yarns obtained according to the usual staple process have a shrinkage of the order of 2 /s%, the additional shrinkage is about l for the cracked spun yarn according to the invention, as against 6 /2 for the spun yarn cracked without the rotating member.

Fig. 2 is a series of curves showing distribution of lengths of cut fibers' the invention; and

Curve b--for a spun yarn obtained without the revolving member.

Maniiestly in the curve a there is a great pro-' portion of longer fibers both in number and more particularly in weight.

In the example described use has been made of a square member 5 having a side of 20 mm. However, smaller or larger members can be used,

.for example of 10 mm. or of 30 mm. per side, re-

volving at appropriate rates of speed determined by the effect sought. It is not essential that the faces of the member 5 should be fiat; for accentuating the edges they can be concave, the tangent planes according to an edge then making angles of less than in the case of :a square,

member; also convex faces can be used.

Members can also be used with a different num ber of edges, for example of 3 edges or of 5 edges.

Even the use of a lenticular rotary member having only two edges can be considered, provided that the edges are not cutting, although distinct- Curve afor a spun yarn obtained according to filaments 'in contact with the edge, but a more regular run is obtained with speeds that are higher by as much as 45% to 60%.

If V is the linear speed of the rollers i and 2 V is that of the rollers 3 and 4 V the speed on the average of the filaments over the member 5 C the average distance between the edges or the member 5 and the point of "departure of the bundle from the rollers I, 2

C the average distance between the edges of the member 5 and the point of entrance of the sliver to the rollers 3, 4.

One can write in first approximation:

For the speeds V and V given and for :8 and @225, which is a practical value, 'oneobtaine'd:

0n the other hand for a speed or rotation-of 65 R.'P. M. the peripheral speed of the member turns "out at '65 20 2. That is to say about 518M, which is 45% greater than the average speed of'the filaments on the member 5.

However, the linear speed of theedges of the member 5' can be substantially greater than this figure. "It can be5'0% to 60% or'more above-Without any "drawback. I

It is well to note that the revolving member can'inoertain cases be replaced with an endless moving band 22 bearing parallel transverse dihedrals 2 3 suitably spacedya's has been diagram.- matically shown in Fig. '3 This device has the advantage of'reducing the'risk of Winding broken thread onto the member. Another-embodiment of the device described completely'eliminate's this risk. In this embodiment, shown diagrammatically in Figs. 4'and 4a, the revolving member is a cylinder l! on which regularly spaced periph eral projections Iii-t5 are fixed, for example four in the form ofteeth of gearings. In order to drive this cylinder use is made of a flexible band i 8, having windows corresponding to the teeth.

In :Fig. 4 the sliver i is supplied by the feed rollers 8, 9 and is taken up by the stretch rollers. The roller 9 drives tangentially the roller I2, which at the same time ensures quite a long contacting path for the bundle upon the roller 9 and thus eliminates theriskof slipping of the bundle upon the feed rollers.

Between the feed and stret'ch'rollers the bundle is "in contact with the four teeth 13, 14, I5 and [6 on the cylinder 21. The latter is driven by an endless belt I8, having (see Fig. 4a) openings f9, 19', 19", 19 registering with the teeth It to it. discharge pulleys 20, 2! and comes in contact likewise with the roller 12 which serves as a scraper to remove adhering fibers.

It-is clear that the risk of winding of broken fibers on the rotary member l? .is totally eliminated in this case.

The belt I8 is driven by suitable means, not shown, and supports the bundle for a substantial distance between the member I] and the roller 20. "It is preferably driven at the same speed as the bundle-or slightly faster than the bundle so as to aid in the drafting caused by the stretch rollers Ill.

Although specific embodiments have been The belt [8 passes further over the and asingle rotary member having projecting non-cutting edges thereon disposed to contact one side only of the bundle and deflect said bundle from a straight 'path of travel between said feed and stretch rollers, means driving Tsai'd rotary member, said bundle being unconfined over said edgesto permit uniform increasein'thelin'ear speed of saidbundle between .saidfeed'rollers and said stretch rollers whereby said edges cause sudden changes in said deflection in the .path of said bundle between said feed and stretch rollers and sudden changes in tension of the bundle adapted to localize the pointsin thefilamentsat which breakage takes place due to thestretching force. I V

.2. .An apparatus asset .forth in-claim. '1 in which a flexible belt is disposed over said member .and has openings for said projecting non-cutting edges, said belt extending along the path of the bundle from the vicinity of said member tosaid stretch .rollers to support the same and being driven at about the maximum speedNo f -said bundle.

3. An apparatus, .as set forth .in claim .2 .in which scraper means is provided toremove fibers from said belt prior to contact with said projecting non-cutting edges.

4. An apparatus as setforth in-claim .linwhich the peripheral speed of the rotating member .is intermediate the peripheral speeds of the isets of rollers.

5. An apparatus-as set forth in'claim l-in which the peripheral speeds of thesets of rollers and the rotating member arerelated accordingto the formula C X (11 C2 in which V equals linear speed of thefeed rollers, V equals linear speed of the stretch rollers,'V equals average speed of the filaments over the rotating member, C equals average distance between the edges of the rotating member andithe nip' of the feed rollers, and '0 "equals average distance between the edges of the rotary memher and thenip of the stretch rollers.

ROBERT HEME DE LACO'ITE. EMMANUEL TEISSIER.

References Cited in the .file of this patent UNITED STATES PATENTS Number Name .Date

1,898,085 Dreyfus et a1. Feb. 21,1933 2,001,000 Taylor et'al. May.14,1935 2,003,400 Taylor etal. June 4,.193 5 2,127,283 'Van Beeket a1 Aug. 16, 1938 2,419,320 Lohrke Apr. 22,1947

FOREIGN PATENTS Number Country Date 104,909 Sweden 'June 30, 1942

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