US1804968A - Manufacture of yarn - Google Patents

Description

May 12, 1931.-

E. E. BLAKE 1,804,968

n MANUFACTURE OF YARN Filed Feb. 27. 1929 5 Sheets-Shea?l l -BY a QATTQRNEY May E2, MSL E. E, BLAKE MANUFCTUREHOF YARN Filed Feb. 27, 1929 5 Sheets-Sheet 2 'y 'r euries.

Patented rMay 12, 1931 UNITED srA'rEsi-PATENT oFFlcE EDMUND E. BLAKE, OF SACO, MAINE, ASSIGNOR TO SACO-LO'EIILl SHOPS, OF NEWTON,

MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS p MANUFACTURE or YARN y Application filed February 27, 1929. Serial 110.843,12?.

This invention relatesto methods of and ,Y

apparatus for working fibrous material into .the form of thread or yarn. The invention is more especially concerned with the drawing 5 and spinning of cotton slivers orrovings.

It is the general object of the invention'to improve the .drawing or .drafting of the rovings or slivers in spinning frames with a view both to improving the quality ,of the resulting thread or yarn and also increasing or lengthening the draft.

In preparing cotton for spinning the fibre first is put through a'series of processes designed to free it from dirt and foreign materials, the last of-these operations being'that of carding. The carding process is also the first of a series of operations designed to bring the fibres into more lor less parallel relationship. The cotton comes from the card in the form of a large sliver which must be reduced materially in size before it can be spun. This. reduction in size a'nd the straightening and paralleling of the fibres is accomplished in a series of drawing operations, the slivers being doubled between the drafting or drawing processes in order to reduce the irregularities and producea more uniform and even sliver. Drawing or drafting is, as its name implies, f the drawing out of the sliver and it necessarily is accompanied by a reduction in the size of the sliver. It is usually accomplished f by running the sliver through successive pairs of rolls, each pair revolving at a greater surface speed than the preceding pair. Before the cotton is ready to go to the spinning frame it is also runl through. a roving frame and'is wound on bobbins. It is necessary to introduce some twist into the slivers in order Ito give them the requisite strength for turns pen 1nch of length according to the fineness of the roving and length of staple. The roving also goes through anothen very important drawing or drafting operation in' the spinning frame immediately prior to being delivered to the spinning instrumenand it is with this drafting operationfibres. In drawing the roving in the spinroll of winding-them on the `bobbins and unwinding4 I 'each palr of them again at the spinning frame, and a slivery so twisted is commonly referred to as a .roving. Commonly the twist is from one to five;

'that thev present invention is especially concerned.

It is obvious that if the length of the draft V used in any .individual drawing operation could be increased materially, either the number of these operations could' be correspondv ,ingly reduced or the production of the reparatory'l machinery be increased;`a nd 'i the quality of the product could be maintained unimpaired, the4 cost of preparation of the fibre for spinning would be reduced. Efforts in this direction, however, are hampered by the fact that the. fibres in any batch of cotton or in any cotton yarn are not of uniform length. Mixed with the longer fibres are a great number of shorter bresof various lengths. The fibres are naturally attenuated spirals in form and they have rough surfaces so that whenthey are drawn over-each other in drafting, the shorterifibres are pulled along with the longer ones simply by their contact with them, and this Contact is extremely uncertain and variable in character. The ideal icondition' in drafting would be to have each while this would be diiiicult even with-'fibres of relatively uniform length,it is made vastly more difficult by the presence of the short ning frame the drafting operation is further complicated by the presence of the required twist in the roving which tends further to lock the libres together and therefore to prevent the very action which the drafting mechanism is designed to produce. v

A typical drafting mechanism of a type commonly used in spinning frames in this country comprises thine pairs of rolls arranged one -in advanceof the other, with one each pair resting on top of the other, rolls being driven at a greater peripheral speed than the preceding pair. All three to' rolls are usually weighted. The nip of theront pair of rollsis spaced from that of the next pair by a distance` very slightly longer than that of the longest fibres, while the distance betweenthe back and middle rolls isl usually one and one-quarter inches. The difference in surface speed of the back and middle pairs 'of rolls is made very small,

the gear or drive ratio usually being between 1.04 and 1.15, and the draft produced bef tween these two pairs of rolls is commonly called the break draft. Usually it is just usual staple has been found to have a decidedly adverse effect on the quality ofthe prod' uct. Week places in ythe roving are drawn excessively and this fact, combined Iwith the difficulty of controlling the shorter fibres,

y makes for results which are not satisfactory.

It-was realized that if the nip of the middle rolls could be brought closer to the nip of the front rolls there would be fewer of these short fibres free from control and that these shorter fibres would be fed to the front rolls in a more regular order. A reduction in this spacing of the front and middle rolls, however, made it necessary to decrease the weight on the top middle roll so as lto permit a greater proportion` of the length of the long ibres-toslip through the middle rolls as they began to be drawn by the faster moving front rolls and thus to avoid breaking them. This, however, resulted in reducing the effectiveness of the middle rolls in producing the break draft. A so-called four roll arrangement, therefore, was developed with the idea of producing a break dra-ft between the back and middle rolls, a draft between the two middle pairs o f rolls, and then the principal draft between the forward middle and the front pairsof rolls.

A further development dealing with this problem involved the substitution of a belt or apron drafting unit for one or more of the pairs of rolls of the three or four roll drafting mechanisms. In a typical arrangement two belts running in contact with each other, or a belt running in contact with a roll, were substituted for one of the middle pairs of rolls of the three or four roll mechanisms. Typical examples of these belt drafting mechanisms are shown in United States Patents d Nos. 1,297,794 and 1,644,747, and in vBritish to the presentinvention.

In all of the prior arrangements, however,

little or no attention seems to havebeen given to the proper correlation ,and arrangement of what I have termed the break draft elements in order to produce a satisfactory conditioning of the roving preparatory tothe main draft. 1n fact', in a very large percentage of drafting mechanisms in present .use no substantial elongation ofthe roving or definite preparation of it is produced prior to the applicationof themain draft. I have found that these factors have a very important bearing on' the results produced in the drafting mechanism of a spinning frame, and that superior results can be obtained and substantial economies realized by properly predetermining and controlling these factors. The present invention, therefore, deals more particularly with the conditioning of the roving. especially the unlocking of the fibres from each other, preparatory to applying the main draft, although it also involves improvements v in the main drafting step. ltinvolves improvements both in the methods of and mech anisms for drawing rovings in a spinning frame.

In addition, the invention aims to improve drawing mechanisms of the belt or apron type with a view to producing` more uniform results, eliminating difficulties in the guiding, driving and cleaning of the belts, and reducing the care and attention required of mechanisms of this character.

The. invention will be readily understood from the followi-ng description when readdn connection with the accompanying drawings, and the novel features will be more particularly pointed out in the 'appended claims.

ln the drawings,

Figure 1 is a vertical, sectionaliew from front to rear through the drawing mechanism of a spinningI frame constructed in accordance with this invention, much of the mechanism being-shown in elevation;

` Fig. 2 is a perspective view of a guiding device for the belt tensioning roll;

Fig. 3 is a perspective view of a portion of a spinning frame; y

Fig. 4 is a diagrammatic sectional view of the drafting rolls and belt and the mechanism for weighting the rolls;

Fig. 5 is a side elevation of a cap bar;

Fig. 6 is a rear elevation of parts of the mechanism shown in Figs. 1 and 3, and

Fig. 7 is a perspective view of one of the belts and the knurled driving roll for it, a part of the belt being shown broken away.

In this specification the strands of material to be treated will be .referred to as roving since the fibre ordinarily is in the form of a roving when it is delivered to the spinning frame, and the spun material will be referred lower roll is knu-rled. The upper rolls are covered with a suitable resilient material, ordinarily consisting of. a cloth cot encircling the metal core vand an outer leather jacket covering thel cot. Each pair of rolls thus is i arranged to grip a roving rmly but yieldingly. The resilient covering also has the effect of increasing the area of contact or bite between the individual rolls of each pair and hence improving the effectiveness of the grip ofthe rolls on, the roving while still avoiding any injurious crushing ofthe fibres. A belt or apron 10 passes between the intermediate rolls 'an'd- 7 an'd has a run extend-v ing forward toward the front rolls and supportedon a stationary bar 12 mounted closely adjacent to the lower front roll 4. From this bar the belt extends downwardly and backwardly around a tensioning roll 14 which is provided withyend iianges to limit the lateralmo'vement of the belt relatively to the roll. This roll is mounted to rise or falland it is guided by two arms 15-15 both piv* oted on a rod 16 at the frear ofthe roll 14, the

' is integral with them so that both arms must move in unison, and the roll 14 thus is kept substantially parallel with the roll 6 which drives the belt. A spring clip 20 sprung over the pivot rod or shaft 16 between the arms 15-15 serves 4to hold these arms against movement longitudinally of the pivot rod.

The belt 10 isl tensioned partly by the weightI of the roll 1'4 and partly, also, by the weight of the arms 15-15.

' Running on the surface of the belt'lO is a small slip roll 21, relatively light in weight, located between the front and intermediate upper 'rolls 5 and 7 and directly above the bar 12.`

The upper rlrolls 5` and 9 rest directly onand are driven byv their cooperating lower rolls 4 and 8, respectively, but the slip .ro-ll 21 and the up-per intermediate roll 7 rest on the belt 10 and are driven by theirengagement with it, the belt, in turn, being driven by the lower middle roll 6. lAll ofthe upper rolls are held in their proper positions by cap bars 22, Figs. 1 and 3, each barfbeing pivoted at 23, Fig. l, at the'rearward part of the stand so that it can be swung upwardly out of its operative position. The rolls 5, 7, 9 and 21 are provided with reduced ends which rest in slots formed in the sides ofy the cap bars 22 and which serve to position the rolls l while permitting them to roll freely. It is desirable to be able to adjust the spacing of the kintermediate roll 7 toward and from the front roll 5, and for this purpose the cap bar 22 has a rod-like member 24, Fig. 5, extending In order to press the upper rolls 5, 7 a/nd 9 'firmly against the driven rolls and thus compel the upper and lower drawing elements of each pair to move at substantially the same surface speed, a saddle 4mechanism is provided w'hich may be of a common type. The construction shown in Figs. 1 and 4 includes' a front saddle 30, arear saddle 31, and a stirrup 32 which is connected to a weighting mechanism of a common type, this mechanism including a lever 33. APressure so applied to the front saddle '30 is divided between the front roll 5 and the rear saddle 31 and the pressure of the latter is divided about equallybetween the rolls 7 and 9. The totaly weight applied maybe varied by using diflerent weights on the lever 33.

A long series of drafting units of the character shown in Fig.' 1 are supported side by side in a drawing frame and are all operated i-n unison by driving the lower ro- lls 4, 6 and 8, the individual roll sections being made on relatively long shafts which are connected together so that they form, in effect, contin= nous shafts extending the entire length of the frame. Any suitable mechanism may be employed 'for' driving the rolls`4, 6 and 8. A-

lar mechanism shownl will be obvious from "i an inspection of Fig. 3 simply with the explanation that the driving gear is shown at 40, the gear 41 is on the end of the roll shaft' 6, and the roll 'shaft 8 is geareddirectly to the shaft 42. It will be understood vthat the front rolls are driven faster than theA interthan the back rolls.

ymediate rolls and the latter revolve faster The usual front underclearer or scavenv' ger roll 36 is provided and a top clearer of some kind, such as the roll 35, is used to clean the 'upper front roll 5.

.A unique' arrangement for cleaning the belt 10 and the rear roll 8 and consists of a clearer roll 37 supported lto run in contact both with the, outer surface of the belt and valso` with the surface of the roll 8., ln` This clearer is made in relatively long lengths so that one roll cleans the belts and back rolls 8 of a considerable number -of has been prqvided drawing units. It is provided at its ends with gudgeon members, one of which is shown at 38, Fig. 1, and each of .these meinbers is supported in a loop 39 formed in a spring 40 which is fastened by a bolt 41 to a part of the stand 2. By depressing the springs 40 which supportthe opposite ends of any clearer roll 37 or by pushing against it, such roll may be slipped backwardly and upwardly out of the machine. Normally, however, the springs 40 hold the clearer roll against the lower back fiuted rolls 8, and it is, therefore, driven chiefly by these rolls, although the 'belts' 10 also tend to rotate the clearer in the same vdirection that it is revolved by the rolls. Due to the grooved construction of the rolls andthe firmer engagement of the clearer with them, they control the movement ofthe clearer and it revolves at substantially the same surface speed as the rolls. This vis slightly slower than the surface speed of the belts and consequently the clearer has a wiping action on the belts which makes it particularly eective.

This clearer arrangement represents a substantial improvement over those Aused heretofore for cleaning the belts of drawing mechanisins in being simpler in construction, more economical to manufacture, more convenient to use, and far` more effective. The prior belt v drafting mechanisms have used an individual clearer for each belt, and a great deal of trouble has been experienced in keeping these clearers in proper working order. An especially serious difficulty has been the tendency of the Hy or lint`to'collect between the ends of adjacent clearers and to twist into the form of a'rope connecting the clearers togethei` these troubles are eliminated in the present construction.

The general organization of the drafting 'mechanism having been described, certain features ofl this invention can now be'explained which deal especially with the preparation of the fibre for themain drawing operation. Bearing in mind the fact that the roving has considerable twist when it comes to the spinning frame, that the cotton fibres vary in length, have a more or less spiral form with rough surfaces, and are interlocked with each other, it will be clear that if a roving is grasped at two points spaced apart by, say, one and one-quarter inches, (as it would be in an ordinary *drawing mechanism), and is pulled at said points, the first effect will be to stretch the roving and to cause the bres twisted around the outside of the roving to bind all the tighter on the inner fibres. My experiments with the break draft mechanisms of the old three roll constructions have shown that if the roving is not pulledmore than,

dition. The gear ratio between the two pairs of rolls which produce this break draft in prior art structures is usually between 1.01 and 1.15, and my experiments with such break draft mechanisms show that no net break draft, or, in other words, no permanent elongation of the roving, is produced in normally twisted rovings until a draft of at least 1.10 is applied. Up to this point the roving is simply straightened out to some extent and tensioned.

I have found, however, that if the gear ratio between the pairs of rolls which produce the break draft is increased to in the neighborhood of 1.32 and the rolls are properly spaced from each other and sufficiently weighted, the fibres in the roving are then so unlocked and loosened that an exceptionally long draft can be applied immediately thereafter without adversely affecting the character of the yarn that will be produced. A. proper spacing of the rolls, however, is required for this purpose inorder to afford the necessary distance or space for the uniform drawing out has been fully stretched lvbetween the rolls. I

For ordinary staples and rovings prepared according to the usual American practice l prefer to make this distance in the neighborhood of one and thirteen-sixteenths inches, and the spacing between centers of bitesor between roll centers should be at least one and five-eighths inches or, better yet, one and eleven-sixteenths inches and should not ordinarily be more than one and fifteen-sixteenths inches. Too great a space ygives unsatisfactory results due apparently to the loss of control of the fibres and the tendency to draw weak points excessively.

-While, as above stated, a gear ratio of approximately 1.32 on ordinary commercial rovings and with usual staples produces the best results, this gear ratio can be made anywhere from 1.27 to 1.37 without seriously affectingthe results, and can even be reduced to 1.20 or raised to 1.45, and still, with the proper spacing of the rolls, produce results decidedly superior to those obtained in the prior art structures. The proper spacing of or, in other words, the permanent elongation of a normally twisted roving, with these gear ratios and spacings is not equal to the full difference in surface speed of the so-called gear draft, but that there is aloss due to the elasticity and straightening of the roving. The gear ratio preferably is made such that the permanent elongation of the roving produced in this part of the mechanism is in the neighborhood of from 18%` to 25%., With such a net break draft produced with drafting of so conditioning a roving for the main draft has not been appreciated'heretofore, nor have the elements of drafting mechanisms been so arranged and correlated as-to produce such preparation effectively.

The malnor principal draft 'is applied by the action of the front rolls 4 and 5 in taking' thefibres as fed to them. As'the kroving passes between the intermediate rolls it comes in Contact with the belt 10, and it is carried forward with the belt under the slip roll 21.

This roll cooperates with the belt to maintain the fibres, especially the shorter fibres,

under control as they move toward the nip of the front rolls and while they are being drawn by the frontrolls. Since the roll 2l rests on the belt and is rotated thereby at substantially the speed of the belt, it does `not tend "to draw the fibres, but it assists in keeping the shorter fibres under better control while allowing the longer fibres to slip under it and over the belt as these fibres are drawn forward by the front rolls. It acts, also, to restrain the tendency of the shorter fibres to move with -the longer fibres simply due to their haphazard contact, and to cause the feeding or drawing of these shorter fibres in their regular turn. This is essential to the production of an even uniform yarnmade from cotton of usual staple.

The action which takes place between the front and middle rolls is quite different from that which occurs between the middle and Vrear'rolls. As above stated, a relatively smally draft is produced between the rear vand mi'ddle rolls and the drawing action. which does take place at that point is, generally speaking, a mass drawing of the entire roving for a very short distance, while that which occurs between the front and middle olls is intended to draw out the individual fibres in their orderly turn. In the preparatory or conditioning draft the .first action is to straighten out and to stretch the roving as a whole, this action tending to contract the rovingv and to some extent to bind the fibres together due to the presence of Ithe twist. I.

have found that when a normal roving is gripped firmly between the rear rolls, a zone of influencejof the twist extends forward forl for a very considerableI distance back of these A rolls due to their-length. The chief purpose of the ydraft applied here is to unlock the fibres and partially free them from eachother and from the twist, although it is desirable to leave a certain amount of twist in the roving because it assists in controlling the fibres o subsequently during the maindraft. In the latter draft the front rolls grip the fibres firmly, and because their surface speed is very much higher kthan that 'of the middle roll, they` draw the fibres out and reduce'the'roving to the desired size and condition for spinning. I e Control of the fibres during the main draft .is influenced materially by the remaining.'

twist and by the spacing of the intermediate rolls with relation tothe front and slip roll. Preferably the slip roll 21 is 'run as close to the upper front roll as practicable, and' thtl center of the slip roll is spaced from the center of the middle roll by approximately fifteen-sixteenths of an-inch, or slightly'less,

seven-eighths of an in'ch usually being the preferred vdistance Vfor staples of less than one `and one-quarter inches. If the slip roll is made half an inch in diameter the distance between the centers of the rolls 5 and 7 will be approximately one and five-eighths inches.

These distances and dimensions have A.been found to produce good results, although it will be understood that they may be varied somewhat. In fact, in running staples of approximately one and one-quarter inches or more it is desirable to set the middle top roll back slightly and this can readily be done, even while the machinery is running, by adjusting the blocks 2,5, as above described; While the roll spacing above mentioned ca r seems relatively short, it is permitted by vthe fact that the roving has been properly con-v ditionedhfor the main draft and t is of ad?v vantage in the better control whic it affords of the short libres. In other words, it leaves a minimum of space in which the short fibres canl be drawn along solely by bre contact.

I have found that in order to enable the slip roll 21 to perform its functions properly its weight is an important factor. Preferably it should weigh in the neighborhood of 1200v grains and this weight should not be. departed from by over 200 grains plus 'or mmus if the best results are to be secured.

apply more pressure on the upper, back and middle rolls than has been the usual practice in orderLto obtain more certain and reliable results. In the mechanism shown rolls of the ordinary size can be and preferably are used. Each of the upper rolls is of approximately fifteen-sixteenths of an inch in outside diameter and has two bossesv or working surfaces/to act on the fibre, the bosses usually being' about one and three-eighths inches in length. In a spinning'frame of two and three-quarters inch gage'and bosses of thesize just mentioned, I have obtained excellent results by applying a pressure'of I,115 I have foundN also that it is advisableito` from 32 to '34 pounds to the stirrup 32 and so adjusting the distribution of this weight i nisms. Or, the draft can be increasedrvery` that approximately 14 to 16 pounds is applied on the front roll 5 and the remainder is` equally divided between the intermediate and rear rolls 7 and 9. As above stated, each roll has two working surfaces or bosses and these surfaces are separated by a reduced portion or neck on which the saddle members act so that the pressure applied to each roll is equally divided between the two workin surfaces or bosses of the roll. It is prefera le'for ordinary staples and twists not tov reduce these pressures applied to the back and middle rolls more than two pounds. Such pressures with rolls constructed as above described give a positive grip on either a single or double roving but will not injure the fibre because of the resilient character of this grip. j

The drafted roving passes directly from the bite of the front rolls'to the spinning instrumentalities which twist it to produce yarn the fibre being fed eontiniiously through the drawing mechanism and to the spinning apparatus. f

The method 'and apparatus herein described have been found in actual practice to produce very substantial advantages over prior artI structures and processes. A stronger, evener and more uniform yarn can be made while still using a draft which would be too high for ordinary drawing` mechasubstantially while still producing a `yarn of as good a quality from a given staple as is produced by the standard mechanisms. Several factors contribute to these improved results, such as the better conditioning of the roving for the main draft, the fact that the majority of the fibres are kept under better control, and Ithe.` fact that the small portion of fibres of maximum length are not injured for broken as usually occurs inl feeding the ordinary staple through the usual drafting *mechanisms` This conserves the very considerable strengthening action which these few longer fibres, if preserved, add to any vto BIIL

The length of the main draft necessarily will depend upon the length and body of they staple,the characteristics of the roving, and.

the results desired. I have found that entirely satisfactory results can be produced by using a main draft equal\to 2, plus 1 for each sixteenth of an inch of length of staple.

In other words, for a seve-n-eighths inch -staple a draft of 16 is entirely satisfactory,

whllelfor a one and one-quarter inch staple a'main draft of 22 gives superior results. Under favorable conditions and with longer staples the draft can be run up considerably higher, for example, from 25 to 30, but perha'pslwith some saerifice of quality. If qual- .ity is thefundamental consideration a draft of inthe neighborhood of 16 is more likely to be used on ordinary staples. With these higher drafts the roving fed to the drawing mechanism of the spinning frame can be relatively large or coarse for a given size, count;y

or number of yarn. This means that an economy 1n the preparation of the yarn for spinning can be realized. Or the mechanism jvariations in twist inthe roving.

While I have herein shown and described a ty ical` embodiment ofmy invention, it will e understood that the invention may be embodied in other forms and that the method of the invention may be practiced with other mechanisms without departing from the spirit or scope thereof.

Having thus described my invention, what I desire to claim as new is:

1. The herein described method comprising the steps of subjecting a cotton roving to a, preliminary draft by grasping it firmly between moving drafting-elements at points spaced at least 1-1l--2,-ths inches apart, driving said elements at a ratio of between 1.20 and 1.45 and thereby feeding the roving through them while they draw it, next subjecting said roving to a main draft, then spinning the roving-so drafted and passing the roving continuously from the first of said drafting operations to the next and from -the latter to the spinning operation.

2. The herein described method comprising the steps of subjecting a cotton roving to a preliminary draft between successive pairs of drafting element-s driven at a ratiolof between 1.20 a'nd 1.45 and which firmly grip the roving at points spaced' at least legs-tbs inches apart, then subjecting said roving to a much greater draft by passing the same be- .tween drafting elements which move at a surface speed substantially the same as that ofthe preceding pair of elements and which gripthe roving with a light pressure while it K Y lzu is drawn-out by additional drafting elements that move at a relatively high speed, and then passing the drafted roving to spinning instrumentalities. n' j 3. The herein described method comprisy ing the, steps of subjecting a cotton roving to a preliminary draft between drafting ele; ments adapted to firmly grip the roll at points spaced from l-il-ths inches to l-ths inches apart and having a driving ratio of between 1.20 and 1.45, next subjecting said rovin g to a main draft while maintainingl the shorter fibres under control, then spinning the roving so drafted, and passing the roving continuously from one of said drafting operations to the next and from the latter to the lspinning instrumentalities. Y

`4i. The' herein described method comprising the steps of. providing a cotton roving vwhich is relatively coarse for the size of thread to beY made from it, subjecting said roving to a preliminary draft which permanently. elongates the roving from 18% to 30%, then subjecting said roving to a mai t draft sufficient to reduce the roving to the size desired for the yarn to be spun, holding the greater part of the fibres` under control during said main draft, then'spinning the roving so drafted, and passing the roving continuously from onev of said drafting' operations to the next and from the latter to the spinning instrumentalities.

5. That improvement in methods of mak- I ing cotton yarn which consists in` subjecting a cotton roving to a preparatory treatment by passing the same between successive pairs of drawing rolls which firmly grip the roving at points spaced at least lajths inches apart, driving said rolls at such surface speeds as tov produce a permanent elongation of said roving of at least 18%, then subject- 4'ing the roving so preparedto a main draft operation.

suflicient to reduce it to the desired size for spinning,finallyspinning the roving so drawn to form a yarn, and passing said roving continuously from one of said drafting steps to the next and from thelatter to the spinning 6L That improvement in methods of making cotton yarns which consists in subject'- Iing a cotton roving to a preparatory treatment by passing the same between successive pairs of drawing rolls, the bites of which are spaced spinning operation.

7. That improvement in methods'of pre- A -paring cotton fibre for spinning which consists in subjecting a cotton roving to a preparatory treatment by passing the same betweensuccessive pairs of drawing rolls constructed to firmly but yieldingly grip the roving and having their'bites spaced oncenters from lths vinches tov lig-ths inches apart, driving said rolls at such surface speeds as to produce-a permanent elongationof said roving ofv between 18% and 30%, and imni'edi-- ately thereafter subjectingthereviiig prepared to a draft of at least 1 l or each sixteenth of an inch of length Iof the staple. i

8. That improvement in'm'ethods of making cotton yarn which consists in subjectinga cotton roving-to a preparatoryF treatment bypassing the same between successive pairs of -drawing .rolls constructed to firmly but yieldingly grip the roving and having their ites spaced from lths inches to. lths inches apart, driving said rolls at such surface speeds -as to produce a permanent elongation of saidroving of between 18% and30%, then subjecting the roving so prepared to a draft of at least 10, next spinning the roving so drafted, ,and passing the roving continuously from one of said drafting steps to the next and from the latter tothe spinning operation. 9. A drawing mechanism for spinning frames comprising, in combination, front,

back and intermediate pairs of drafting elements, each adapted to grip a roving-firmly between them, means for supporting said elements in their operative positions, the centers of the bites/of said intermediate and back elements being `spaced at east l-thsi'nches from each other, and mechanism for driving said lower elements to produce a drive ratio between said rear and intermediate elements of from 1.20 to 1.45 and a substantially higher drive ratio between said intermediate and ofront, elements.

' 10. A drawing mechanism for spinning g frames comprising, iin combination, front, back and intermediateipairs of drafting rolls,

Aeach pair comprising an upper and a lmverY roll for gripping al roving firmly between them, means for supporting said rolls in their operative positions, the centers of the bitesy of said intermediate and back rolls being spaced at "least lygths inches from each other, a belt passing between said intermediate rolls and' having a run extending forward toward the bite of ,said front rolls, means located closely adjacent to the lower of said front rolls for supporting said lbelt at the forward end of its run, a slip roll resting on said belt `between said front and intermedi-ate rolls,

and mechanism for driving allv of said lower rolls to produce a drive ratio between said back and intermediaterolls of between 1.20 and 1.45, and a substantially higher drive ratio between said intermediate and front l rolls. v

11. A drawing mechanism )for spinning lframes comprising, in combination, front,

back and intermedlate pairs of drafting rolls,

each pair comprising a lower roll and a resilient upper roll, means for supporting said rolls in their operative positions and holdingv ,125

rolls, a stationary bar located closely adjacent to the lowerof said front rolls and sup porting said belt at the forward end of its run, a slip roll-resting upon said belt above said bar closely adjacent the top front roll, mechanism for driving all of said lower rolls to produce a drive ratio between said back and intermediate rolls of from 1.20 to 1.45 and a substantially higher drive ratio between said intermediate and front rolls, and means for applying a pressure of at least six pounds on each of said upper, front, intermediate and back rolls.

12. A drawing mechanism for spinning frames comprising, in combination, front,

back and intermediate pairs of drafting rolls, each pair comprising an upper and a lower roll, means for .supporting said rolls in their operative positions and holding said intermediate and back rolls with their bites spaced on centerskbetween /8ths inches and lths inches from each other, a belt passing between said-intermediate rolls and having a run extending toward the bite of said front rolls, a stationary bar located closely adjacent to the lower of said front rolls and supporting said belt at the forward end of its run, a slip roll weighing between 1,000 and 1,400 grains and resting on said'belt between said front and intermediate rolls, mechanisin for driving all of said lower rolls positively to produce a' drive ratio between said rear and intermediate rolls of. from 1.205 to 1.45 and a. substantially higher draft between said iiiterinediate and front rolls, and means for pressing the upper of each of said pairs of rolls toward its respective underlying roll to firmly but resiliently grip a roving fed between said three pairs of rolls.

13. A drawing mechanism for spinning frames comprising two pairsof drawing rolls arranged one in advance of the other, each pair comprising an upper and a lower roll, mechanism for driving said front rolls at a greater surface speed than the rear rolls, a belt passing vbetween said rear rolls and having a run extending forward toward the bite of said front rolls, said belt also including a loop lying below said rolls, a tensioning roll in the lower part of said loop having flanges at its opposite ends to limit the lateral movement of said belt with reference to the,

guiding said tensioning bite of said front roll` means located closely f adjacent to the lower of said front rollsfor supporting the beltat the forward end of its run, a'slip roll resting on said belt between said upper, front and intermediate rolls, said fzlip roll being located closely adjacent to said upper front roll and bearing on said belt at a point spaced between thirteen-sixteenths and fifteen-sixteenths of an inch from the point at which said upper intermediate roll bears on said belt, and mechanism for driving all of said lower rolls to produce a driving ratio between said back and intermediate rolls of between 1.20 and 1.45 and a substantially higher drive ratio between said intermediate loop lying below said rolls, a gravity belt tensioning roll in the lower part of said loop having flanges at its opposite ends to limit the lateral movement of the belt with reference to the roll, and pivoted arms located at l the opposite ends of said tensioning roll for guiding and weighting the roll. 16. A drawing mechanism 'for spinning frames vcomprising in combination, front, back and .intermediate pairs of drafting rolls, each pair comprising an upper and a lower roll, a belt passing between said intermediate rolls and having a run extending forward toward the bite ofthe front rolls and a loop extending downwardly below said rolls, a removable clearer roll running in contact both with the outer surface of said belt and also with the surface of said lower back roll, and means for supporting said clearer rollin its operative position.

17. A drawing mechanism for spinning frames comprising, in combination, front, back and intermediate pairs of drafting rolls, each pair comprising an upper and a lower roll, a belt passing between said intermediate rolls and having a run extending forward toward the bitepof the front rolls and a loop extending downwardly below said` rolls, a

the rear of said belt and engaging the shaft of said tensioning roll at opposite sides of the belt, said arms serving tol guide and weight the roll, a clearer roll running in con` tact both with the outer surface of said belt and also with the lowerof said back rolls, and yielding means vfor holding said clearer roll in its operative position.

18. In a drawing mechanism, th combination of a series of drafting unitsI arranged side by side, each unit comprising a plurality `tensioning roll in said loop, arms pivoted at cluding a y yin unison, a single clearer vroll or cleaning `the belts of a plurality of dpairs of drafting elements spaced apart an arranged to act successivel on a roving to draw it, one of said pairs o elements including a belt, means for drivin said units in unison, a single clearer roll or cleanin the belts of a plurality of said units, an means for removably supporting said roll in its operative position.

19. ln a drawing mechanism, the combination of a series of drafting units arranged side by side, each unit comprising a plurality of pairs of drafting elements spaced apart and arranged -to act successivel on a roving to draw it one of said pairs o elements inbelt, means for drivin said units means for revolving sa1d roll independently of said belts. l

20.-]n a drawing mechanism, the combination of a series of drafting units arranged yside by side, each unit compmsing a plurality of pairs of drafting elements spaced apart,

and arranged to act successively on a roving to draw it one of saidpairs of elements including a belt, means for driving said units in unison, a single clearer roll for cleaning the belts of a plurality of said units and means for driving saidroll at a different surface speed from that of said belts.

21. In a drawin mechanism, the combination of a series o drafting units arranged side by side, each unit comprising a belt and a plurality of pairsof drawing rolls, means for driving said uits in unison, and a clearer roll engaging the belts of a plurality of said units and also engaging one of the rolls of the latter units and arranged to be driven by` such. engagement. Y

l EDMUN D E. BLAKE.

of said units, and

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