US2611155A

US2611155A - Device for parallelizing fibers in sliver or roving during drafting

Info

Publication number: US2611155A
Application number: US114562A
Authority: US
Inventors: Benjamin B Cravens
Original assignee: Whitin Machine Works Inc
Current assignee: Whitin Machine Works Inc
Priority date: 1949-09-08
Filing date: 1949-09-08
Publication date: 1952-09-23
Anticipated expiration: 1969-09-23

Description

P 1952 B. B. CRAVENS 2,611,155 PARALLEL-IZ ,DEVICE FOR I ING FIBE IN SLIVER OR .ROVING DURING DRAF' G I Filed Sept. 8. 1949 2 Sl-lEETS-SHEET 2 INVENTOR.

BenjmminBflrm/em BY ATTORIEY Patented Sept. 23, 1952 DEVICE FOR PARALLELIZING FIBERS IN SLIVER R ROVING DURING DRAFTIN G Benjamin B. Cravens, Pawtucket, R. I., assignor, by mesne assignments, to Whitin Machine W0rks, a corporation of Massachusetts Application September 8, 1949, Serial No. 114,562

My invention relates to a new and improved method and apparatus for drafting natural or synthetic textile fibers' in strand form, such as sliver, roving, and the like, in drawing mechanisms of drawing frames, roving frames, spinningframes, and similar textile machines.

Many different forms of condensing devices have been proposed heretofore for reducing sliver, roving, and the like to greater compactness in textile drawing operations. The art has, heretofore; developed compacting or condensing devices in the form of a funnel or trumpet, either as a closed tube or with an open slot or passageway at the top. Devices of this character in use at the present time usually are attached to a traverse rod for reciprocating movement transversely of the path-of fiber travel and positioned a substantial distance clear of the nip formed by the drafting members which immediately fol low the condenser thereby relinquishing control of the sliver, roving or fibrous strand as soon as it clears the outlet'of the funnel or trumpet with consequent loss of the fiber condensing effect due to the tendency of the fibers to splay and swell out in the free span between the outlet of the condenser and the nip of the fiber-pulling members following the condenser.

The whole purpose of drafting, as performed in drawing frames, roving frames, spinning frames, and similar textile machines, is to effect a combination of separating lengthwise, or drawing apart, the "fibers of cotton, wool, rayon, or other "fibrous textil weaving material, into a thinner strand and parallelizing the fibers in the strand of sliver or roving. As above stated, present forms of condensing devices tend to defeat the basic principle of parallelism byturning inwardly or lapping the fibers over each other. Obviously, lines of fiber travel which cross each other cannot be parallel toeach other. It is believedthat greater draft, of more uniform consistency, can be obtained by eliminating the intermixing or overlapping of fibers from the edges of the sliver being drawn toward and over the inner fibers of the strand or sliver, through the use of improved design of the condensing devices and the imposing of new'means of controlling by means of a novel method and apparatus wherein the fibers of the sliver or roving during; a

drawing operation arecaused to travel between J two positions, one being a position at which "the array or strand of sliver or roving is substantially 7 Claims, (01. 19-430) fiat in transverse cross-section and a second position at which the strand is in a condensed and compacted form, the fibers of the'strand being caused to travel during the drawing operation along courses of equal length in passing from;

the first position to the point where they are condensed and compacted and at which they arrive in converging lines of flow under tension; the arrangement being such that the distance traveled, and consequently the tension, being I substantially uniform for all lines of travel or courses made by the individual fibers throughout the width of the sliver or roving in passing between the two positions; and further charv acterized in that the sliver or roving is put in a compacted condition solely at the second p0sition. My invention also is directed to the provision of a mechanism for drawing sliver or rov- 1 ing for making yarn and includes in its organization a pair of opposed holding rolls receiving a strand of sliver or roving and between which the strand passes in a compressed flattened form or ribbon-like strip, a pair of opposed rotatable pulling members or rolls cooperating to provide a line of nip therebetween and arranged to draw those fibers of this strip whose front ends are gripped by the pulling members and whose tail of holding rolls and pulling members, and by means of which device the drawn fibersv are dis-1 placed in opposite directions for an amount such that they are caused to travel in courses of equal length to straighten out the fibers so that they will pass into a condensing and compacting region in a more nearly parallel relationship toeach other before entering the bite of the pulling members.

This condensing device comprises a support ing body which includes a fiber condensing and compacting member having a restricting-discharge aperture the delivery end of which is 'to be placed close to the nip of thepulling members when the device is in its normal working position, a convex fiber spreading and distributing mem-. ber situated in advance of said fiber compacting member, and a convex member positioned ahead of said fiber spreading and distributing member, and arranged to tension and guide. the fibers., thereto after the strand has passed the bite of the convex members, the fibers situated near the.

mid-portion of the main body ofthe strip being caused to follow a course having the greatest deflection from a straight linewhile those close to th side edges of the strip'make a course'having the least deflection in passing under and over the convex members as the courses of the drawn. fibers are caused to converge to the compacting member. In addition, my invention further. contemplates a condensing device which is so fashioned that it willcreateaslight tension in the strandof sliver or roving, independent of the standarddraft of: the machine, starting as the sliver or. roving passes into, the entrance area of my improved condensing device. The friction thus imposed will press thefibers against or'toward successive reverse bends presentedby the condenser transversely of the sliver or roving.

vIn practice, the condenser. is provided with twooppositely convex curved bending members arranged transversely of the strand of sliver or roving to operatesuccessively thereon to bend it in-opposite transverse directions as the sliver orrcving passes under and;over said curved surfaces, the fiber engaging surface of. each of said bending members'being curved-convexedly both laterally and longitudinally. Consequently, naturallines of force willcause the. fibers to attemptto, retain their. original lateral relationship in. passing through this new condenser. rather than to gather or to fold over each. other, which latter result is obtained. in use of present funnel types of condensing devices.

Another feature of my invention contemplates the reduction. to. a minimum of the length of travelof the fibersthrough the. discharge orifice of the, condenser to an extent whereby the fibers arenot able to.cross each other within the orifice;

A further featurev of my invention contemplates. a notched compacting member forming the exit end and the. fiber discharge orifice of the condenser device for condensing the sliver or roving following its passage across thecurved bending members; the width and depth of said orifice being restrictedto the natural space requirements of the strand of sliver or roving whereby a more completely parallel positioning of the fibers will beaccomplished.

Parallelism during condensation of the fibers is'eifected in my improved condenser design by drawing all fibers through the same linear distanceto the discharge orifice of the condenser device. The convex bending members interposed between the notched compacting member and the holding members, or rolls displace the portions of thestrands of sliver or rovin in opposite directions for an amount suchthatthe distances alon the converging lines or. courses of travel of the drafted fibers. between the fiber holding members or rolls and the compacting member of the condenser are uniform and equal; conr the condenser.

of the pair of opposed pulling members, such as drawing rolls, belts or aprons, when operating on sliver or roving and between which the fibers must pass to the next draft stage, and yet avoid clogging of the machine. Consequently, the fibers are not given an opportunity to curl or deflect from the intended lineof travel. This free distancepreferably should be shorter than the length of the individual fibers (average) and theradius of their natural curling arc.

By theeliminationof any trumpet action or gatheringtogether of the fibers within the condenser umt ahead of the orifice, the tendency of. the fibersto intermingle and be forced out of parallel positiongis removed. The width of my condenser should be made wider than the lines of force. impelling the, travel of the sliver at all points excepting at the discharge orifice itself.

Bydefiecting the strand of sliver or roving under and over the opposed convex curved surfaces of.my bending members which are so placed that theintersecting line of the arcis essentially p-arallelto thelines ofcontact of the rolls limiting-the draft area, the fibers will be restrained frombunching and folding or crossing one another during the condensing operation. The radius of curvature of the convex curved bending surfaces is calculated so that the natural friction of the fibers will balance with the tendency to outwardslippage of the fibers as they pass over the curvature of these arcs, thus placing and holding each of the fibers ina natural line of travel from the'point of leaving the precedin draft roll and the point of entry in the orifice of The radii of the various arcs might vary with different draft ratios and weights of sliver employed andthe width of the strand as it enters thearea in which my inventionisused.

The overall length of thecondenser preferably should be shorter than the average length of the, fibers being drafted in order to eliminate any tendency of the fibers to draft to any material extentv within the condenser in excess of the ratio of draft in the draft area into which the condenser is inserted.

The amount of deflectionof the sliver or roving passing through the condenser is such that excessive friction, which might separate the fibers, or break the continuity of sliver, is eliminated.

The arcs should have such radii that the theoretical travel distance through the condenser will be constant for any given course of travel in thedraft area, within the normal working limits of the width of sliver or roving and range of traveler motion.

It is accordingly one object of my. invention to control sliver or roving in the process of drafting in such a fashion as to cause the individual fibers to travel throughv equallinear distances as the strand of fibers is being attenuated in a drafting mechanism.

Another object of my invention is-to provide an improved condensing device which can be positioned close to the nip of the fiber pulling members and so arrangedas to cause the relationship of fibers to be maintained during the condensing process in such manner that there will be no tendency for fibers to clim over each other or to fold the strand in any way.

Other objects and advantages of my invention Willbe more apparentby reference to the follow ing detailed descriptionof the several embodiments of my apparatus. and. method chosenv for the purpose of illustration in the accompanying drawings, and the novel features of my invention claims. I

In the drawings:

Fig. 1 is a diagrammatic view, in elevation;

above and looking down into the condenser de vice from a side thereof;

Fig. '4 is an enlarged form of condenser device similar to that shownin Fig. 2 but with side restricting walls on the middle transverse bend member;

Fig. 5 is an enlarged transverse section taken substantially on the line 5-5 of Fig. 4;

Fig. 6 is an enlarged front elevation of another modified form of condenser device similar to that of Fig. 2 but with a side opening in the outlet for'threading purposes;

Fig. 7 is a diagrammatic view, in elevation, i1;- lustrating one embodiment of my improved method and showing one of my improved condenserdevices in a drawing mechanism for performing the method of my invention to cause the individual fibers to pass through equal linear distances as the strand of sliver or roving is being condensed in a draft zone; and

Fig. 8.is a diagrammatic top plan view i1- lustrating the'condensingaction of my improved condenser.

Referring to the drawings, Fig. 1 shows spaced pairsor setsof upper and lower cooperating rolls II), 'II and I2, [3, respectively which also are respectively the front and rear rolls of a draft stage or zone of a drawing mechanism associated with either a roving frame or a spinning frame. Thus, the pairs of rolls H), II and I2, I3 may provide either a draft stage of great draft for the fibers being processed or they may form merely a tension draft zone in the drawing mechanism of such textile machines. If desired, the fiber drafting organization provided by the rolls II), II, l2 and i3 may be utilized in combination with a break draft stage or zone which as usual precedes one or more greater draft stages or zones indrawing mechanisms of this class, in which instance, the pair of back or feed rolls l4 and i5 and the rolls [2 and i3 provide a break draft zone as illustrated in'Fig. 7.

The top rolls Ill, l2 and M are of conventional construction each comprising a relatively short roll having fiber engaging portions covered with leather or other covering material in common use.

The top rolls of each set are pressed against their associated lower rolls by means of suitable pressure weighting mechanism, as is well known practice in the art, and not here illustrated, whereby the array or strand of fibers S passing between the pairs of drafting rolls will be firmly gripped thereby-and carried forward in succession between each pair of rolls and the desired drafting effected if the settings of the pairs of drafting rolls are properly adjusted and the relative surface velocities and speeds of the rollsis provided.--

plan view of a modified The bottomwolls 1 I, c and. 15% arejzposi'tive'ly'a driven and ofusual construction as commonly; used in theart' in that. each may. consist of a longitudinally fluted metallic roll of considerable length made up of anumberof short fluted sec tions joined together end to-end by suitable coupling means (not shown) The construction'zand arrangement of these rolls is conventional and 1 well known in the art sothatfurther' description will notbe given except to state that the bottom rolls are journaled for rotation in suitable bear ing members (not shown) which are arranged for; relative adjustment and may be set appropriate for the staple of the fibers. beihgdr'afted; v In practice, the bottom rolls may or may notlbei'z caused to be rotated at"increased'speeds to-provide faster surface velocities'to the succeeding?" rolls engaging the'fibrous strand Sof roving or! sliver in its forward travel" from the pairs of'rolls' l4, l5; l2, l3 and 10,. respectively whereby it" is the accepted practice in the'art to so operate and regulate-the several successive 'sets of rolls? that they will rotate with the proper peripheral velocities to effect the required total draft of the strand of sliver or roving S passing between them during its forward travel through the successive' other suitable source of supply, and feed it for ward to the pair of intermediate draft rolls [2- and I 3. In front of these are shown the front" or delivery rolls l0 and II. In practice, the 7 fibrous strand S may be drawn through a'rear trumpet (not shown) before entering the bite ornip of the back rolls Mand l5, as is a usual practice in the art. 7

Thus, in accordance with the foregoing de scription, the three consecutive pairs or sets of rolls shown in Fig. 7, of which the Fig. 1 repre-' sentation may comprise a portion thereof, there will be provided two consecutive draft stages or zones, the first being a break draft area be-' tween rolls [4, l5 and l2, l3, and the second be--' ing an area or stage of greater draft, the break draft being of the order of 1.25 or upward. The second draft zone is between the pair of rolls I2, l3 and the next succeeding pair Ill, H.

Between the cooperating pairs of rolls l0, ll and the rolls l2, I3 is arranged my novel and improved fiber reducing device or condenser Iii. If desired, the drawing mechanism may include a succession of additional pairs or sets of draft rolls to supplement the roll arrangement shown in" Fig. 7 so as to add draft stages or zones and to provide either a four-line or a five-line drawing system in which instances similar condensers or reducers of appropriate size may be placed between one or more of the succeeding draft stages. The specific structure of my condenser or reducer device l6 now will be described in detail as the specification proceeds.

It will be understood that in connection with the following description the terms employed in so describing my condenser or reducer device and .in claiming it, such terms as front, middle,"

ard. upper. rearwardly, bev ted, and downwardly" are to be .considered as relative rather than limiting as the posi-I iwhich is suitably secured to an angle bracket" 7 i l3, both legs of which are. bifurcated: as shown in Figs. 2- and 6 and secured to a traversebarl9 (seeFigs. 1, and 7). by which it is positioned and supported in operative relation with respect to two pairs or sets of draft rolls in the drawing mechanism of the machine with which it is used- The overall length of the condenser preferably should be made such that discharge of the fibers will be. as close as. possible to the nip of the succeeding pair of rolls while entrance of the fibers can be as close as possible to the pair of rolls immediately preceding the condenser. This overall length of the condenser, however, should be. shorter than the rated length of fibers being.

drafted.

The base. incorporates a rearwardly disposed transversely extending curved bend or arm meme ber 20, a middle or intermediate elevated trans-. versely extending curved bend or expander mem-. ber 2|. and a forward extension in the form of an, upturned notched compacting member 22. The underside of the back bend or arm is curved convexly both longitudinally and trans-v versely as shown by the convex are 23 in Fig. 2 and the convex are 24 in Fig. 1 respectively, and is spaced above and extends transversely of th base portion l1.

The qmiddle bend or expander member 2| is of special formation, here shown in Figs. 1, 2 and 3 as being of relatively sharp triangular section longitudinally of the base and having its peak or transverse ridge 25 on a convex curved are extending transversely of the base portion H. The rearward side ofthe expander member 2| is curved laterally on its upper face 26 on a convex surface formation to the ridge 25 and is slantingly directed downwardly therefrom and terminates partially beneath the back bend or arm 20. The forward side of the expander member 2|- also is curved laterally on its upper face 21 on a convex surface formation to the ridge 25 and is slantingly directed toward the rear portion of the upturned compacting member 22 and at its forward end being on aconcave curve and m rging into the upper forward surface portion of the'compactingmember 22. In its front upper portion the compacting member 22 is on a convex curve and hence the upper surface from the front end of the compacting member 22 to the ridge 25 as a whole represents a compound curved surface. Formed in the compacting member 22' is a downwardly inclined central discharge aperture 28 which extends therethrough and is shown at 29 as being of partially circular formation the curved sides of which join at their upper ends with the sides or a relatively deep sharp notch 30 which forms the compacting orifice of the member 22.

The condenser structure above described thus will cause the initial relationship of fibers to be maintained during the condensing process so that there will be no tendency for fibers to "climb over each other or to fold the web in any way, i. e. the fiber which leaves thepreceding rollers at the left outer edge of the web will still be at the left outer surface of the condensed web, the only dislocation will be the unavoidable stacking of fibers requisite to passage through a narrower space. Since contact of the fibers within the central aperture 28 and the notch 30 must be so short that the natural tendency of the fibers to climb over each other in passage through this restricted area will be reduced to a minimum, the width of aperture 28 andthe not h h uld e es cie te h natu l tate. I

equire e ts of h t a d of; s i e orroving. Also, the notch 30 is made narrower than the transverse length of the convex bending members whereby the fibers of the sliver or rovingare caused to travel along converging lines.

The radii of various-arcs and lengths of my condenser device may vary with different drafts, weights of sliver or roving, the length ofthe draft zone and width of strand being processed. All sharp corners, either inside or outside, should be eliminated. ljhe surfaces which contact the sliver or roving preferably should be as short as practical in relation to the longitudinal travel of sliver or roving through the condenser. Dur-.v ing passage of fibrous strand through my condenser device the edges of the sliver or roving should be practically undisturbed in line of travel from the pair of fiber engaging rolls immediately preceding the condenser to the discharge orifice of the condenser. The distance traveled by the center fibers of the strand is determined by control of the size and shape of the notch 30, the ciuvature of the upper surface of convex are 25 of the middle bend, andthe curvature of the lower surface of convex are 23 of the back bend 20. Friction in passage of fibers through this condenser is reduced to the minimum required to obtain sufiicient dislocation of line of fiber travel to accomplish passage of fibers through the same distance within the zone, whether the fiber leavesthe preceding rolls at the outside or inside of the web, without causing the fibers to slide sidewise on the convex curved surfaces of the condenser bends. In practice, the convexed curved transverse bending surfaces ofthe bending members 20 and 2| of the condenser should be made sufficiently wide so that fibers at the outer edges of the sliver or roving will not touch any side restriction until they actually enter the discharge aperture 28 and the notch 33, and at that point the lines of travel of the fibers will be in controlled relationship to vertical pressure instead of sidef pressure and will be. devoid of trumpet action by the condenser.

In Figs. 4 and. 5 I have shown a modified form of reducer device or condenser which differs from the form of construction illustrated in Figs. 1, 2 and 3 in that the ridge or expander member 2| is provided at its sides with upstanding guide walls 3| and 32, the inner faces of which are convexedly curved longitudinally of the device. In a drawing operation there is frequently experienced a tendency for certain fibers at the edge of a moving strand of sliver or roving to fly outwardly away from the strand and become disassociated and lost; consequently, the convex guide walls 3| and 32 provided in this modified form of device will deflect these disassociating fibers back toward the strand, thus preventing the loss of such fibers. The guide walls 3| and 32 are here illustrated therefore as an adjunct to the device of my invention and they have no direct bearing on the principal functions thereof.

In Fig. 6 I have shown another modified form of reducer device or condenser in which the outlet opening in the forward compacting member 22 is slotted at ,one side as at 33 to facilitate threading of the strand of sliver or roving into the aperture 28 and the notch 30.

Fig. 8 is'a diagrammatic presentation of the The;

'lirie's A'Afarid BB represent -the centers of c'ontactiof the fiberholding and pulling ro1ls,.respec- "ti'vely, of the I draft: zone "illustrated, while the lines CC and. DD illustrate the actual nip lines -of--the'respective rolls. Lines 20-20 and 2l-2i in this figure represent the center lines of the back bend 20 and'the middle bend 2| respectively of the condenser device l6. The distance between line 20-20 and point 30 which indicates "the compacting notch of the device represents the effective length of the device. The line EE represents the natural distance from the point where the outer edge of the strand of sliver or roving is discharged from preceding rolls to the point of compaction.

The line EF represents the'natural center of the strand of sliver or rovi'ngf Line EG represents-any other line or distance-between EE' and EF, here illustrated midway of the distance between the center and outer edges;- of the strand. Convex arcs 23 and 25 have radii so computed that the points of intersection with line EE will not deflect the strand and the sum of the converse altitudes of the arcs-{from lines 20-20 and 2|--2l, respectively,

Therefore, the length of line What I claim is:

1. A condenser device for sliver or roving comprising a support and two oppositely convex curved bending members arranged transversely of the sliver r roving and bending it in opposite transverse directions as the sliver or roving passes under and over the curved surfaces of said bending members, and a notched compacting member forming the exit end of the condenser device for condensing the sliver or roving following its passage across said curved bending members.

2. A condenser device for sliver or roving comprising a support and two oppositely convex curved bending members arranged transversely of the sliver or roving and bending it in opposite transverse directions as the sliver or roving passes under and over the curved surfaces of said bending members, and a compacting member having a notch therein forming the exit end of the condenser device, said notch being narrower than the transverse length of said curved bending members whereby the fibers of the sliver or rovin are caused to travel along converging lines.

3. A condenser device for sliver or roving comprising a support and two oppositely convex curved bending members arranged transversely of the sliver or roving and bending it in opposite transverse directions as the sliver or roving passes under and over the curved surfaces of said bending members, and a compacting member having a notch therein forming the exit end of the condenser device, the underside of one of said bending members being convexedly curved both transversely and longitudinally, the upper surface of the other of said bending members being convexedly curved transversely and in its longitudinal extent rising upwardly to a peak forwardly from the back of the condenser and thence sloping sharply downwardly and forwardly from said peak to merge with the'upper side of said compacting member to define therewith a compound curved upper surface.

'4. In a mechanism for drawing textile sliver Ior roving, the combination of a pair of opposed rotatable holding rolls receiving a strand of sliver orroving and through which it'passes in a compressed flattened condition, a pair ofo'pposed rotatable pulling members cooperating with each other to provide a line of nip therebetween and arranged to turn togetherat a peripheral speedlgreater than that of theholding rolls so. as

' to draft and attenuate. the strand as' 'well'as to propel it forwardly and away from said'holdihgrolls under'tension; anda device for'con- ,densing and compacting the fibers of the strand .and located in the-drafting zone between said z'pairs ofholdin'g rolls and pulling members, said device comprising a fiber condensing and compacting member having a restricted discharge aperture the delivery end of which is positioned close to the line of nip of said pullingflmembers,

and a plurality of convex curved members situated ahead of said fiber condensing and compact ing member and between it and the holding rolls, the curved surfaces of said convex members being; disposed transversely of the strand so as to engage in succession opposite sides of the moving strand and bend it in opposite transevrse directions as the strand is guided over said convex members for an amount such that the drawn fibers arecaused by the convexity of said'convex members to travel along courses of equal length .in" passing from the holding rolls to the condensing and compacting member of the device under conditions of substantially uniform tension-throughout the width of the sliver, or roving.

5. In a mechanism for drawing textile sliver or roving for the manufacture of yarn, the combination of a pair of cooperating holding rolls receiving a strand of sliver or roving and through which it passes in a compressed flattened condition, a pair of rotatable pulling members in cooperating relationship and arranged to draft and attenuate the strand as well as to propel it forwardly and away from said holding rolls, and a device-for condensing and compacting the fibers of the strand immediately before the fibers are gripped by and pass between the pulling members, and to control the movement to the compacting region of the fibers in that portion of the strand undergoing draft, said device being located between the holding rolls and the pulling members and comprising a fiber condensing and compacting member having a restricting discharge aperture, convex means arranged to spread and distribute the fibers of the moving strand laterally thereof and to guide the fibers to the condensing and compacting member, and convex means arranged to tension and guide the fibers of the moving strand to said convex fiber spreading and distributing means after the strand has passed away from the bite of the lbiolding rolls in advancing to the pulling memers.

6. In a mechanism for drawing textile sliver or roving for the manufacture of yarn, the combination of a pair of cooperating holding rolls receiving a strand of sliver or roving and through which it passes in a compressed flattened condition, a pair of rotatable pulling members in cooperating relationship and arranged to draft and attenuate the strand as well as to propel it forwardly and away from said holding rolls, and a device for condensing and compacting the fibers of the strand immediately before the fibers are amines "gripped by and pass between the pulling members, and'to control the movement to the compacting region of the fibers in that portion of the strand undergoing draft, said device being located between the holding rolls and the pulling members and comprising a fiber condensing and compacting member having a restricting discharge aperture, convex means arranged to spread and distribute the fibers of the moving strand laterally thereof and to guide the fibers t the condensing and compacting member, and convex means arranged to tension and guide the fibers of the moving strand to said convex fiber spreading and distributing means after the strand has passed away from the bite of the holding rolls in advancing to the pulling members, said convex convex fiber tensioning and guiding means being situated with respect to each other, said holding rolls, and said condensing and compacting member so as to alternately engage the top and bottom portions of the flattened strand passing thereover and to impart successive transverse displacements to said portions thereof in opposite directions for an amount such that the drawn fibers are caused to travel in longitudinal courses of equal length in passing from the holding rolls to the condensing and compacting member of the device.

7. In a mechanism for drawing textile sliver or roving, the combination of a pair of opposed rotatable holding rolls receiving a strand of sliver or roving and through which it passes in a compressed fiattened form, a pair of opposed rotatable pulling members cooperating to provide a line of nip therebetween and arranged to draw the fibers whose front ends are gripped by the pulling members and whose tailien'ds .are'sublect to a retarding tension by adjacent other fibers held by the holding rolls, as well as to advance the strand under tension during the drawing operation, and a device for condensing and compacting the fibers of the strand and located in the drafting zone between said pairs of holding rolls and pulling members, said device comprising a base which includes an upturned fiber condensing and compacting member having a notched aperture the delivery end of which is positioned close to the line of nip of said pulling members, an intermediate elevated fiber expander member with a transverse ridge curved on a convex line for spreading and distributing the fibers of the strand laterally of its width as the moving strand passes over said ridge, and to guide the fibers to the condensing and compacting member, and a fiber tensioning arm member the underside of which is curved convexedly both longiudinally and transversely and arranged above and extending transversely of said base for tensioning and guiding the strand to said fiber expander member after the strand has passed the bite of the holding rolls in advancing to the pulling members.

BENJAMIN B. CRAVENS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS