US2206242A - Manufacture of yarn - Google Patents

Description

July 2, 1940. J. TRUSLOW MANUFACTURE OF YARN Filed Aug. 51,1935

Patented July 2, 1940 PATENT err-"Ice momma or YARN James L Truslow, Whitinsvllle, Mass assignor to Whltin Machine Works, Whitlnsville, Masa, a corporation of Massachusetts Application August 31, l 4 Claims.

The invention is for simplifying the manufacture of yarn, particularly cotton yarn, and includes a new correlation of drafting steps constituting a new yarn process and a new machine by which the process can be carried out. By this process ordinary draw-frame sliver is converted into a superior yarn with fewer workings of the fibres and the use of fewer machines, andhence with a lower cost for labor and equipment,

5 than heretofore considered possible for like results. It is particularly economical and specially recommended for yarn counts of about s and above. It differs generally from standard mill methods in that the roving is made in one-cong tinuous passage through, a number ofsuccessive draft stages performed in one machine, from which the roving goes, single or doubled, to the spinning frame to be spun into yarn with further draft in the usual way. The novel characteristic 0 of the new process is that the major part of the draft required to convert the draw-frame sliver into roving is appliedin an initial stage of its passage through the single machine, and the-rest f of the draft is applied in the later stages with the aid of a false twist applied to the stock immediately following the stage of longest draft.

The machine of the invention consists of an improved .form of fly-frame containing in itself the sufllcient number of draft stages to produce 30 roving from draw-frame sliver .in one passage, and in the particular stage sequence referred to, and affording special advantages in respect of mechanical efllciency, ease of maintenance and general convenience, all as will be apparent below. In the drawing-'- Flg. 1 is a vertical cross section through-the drafting system of such machine and Fig. 2 a plan thereof.

In its general construction the new machine can be the same as any standard fly-frame or slubber and since such machines are well known,

' the drawing omits those parts not directly concerned withthe invention. The usual flyer is marked I, the roller beam and roll stands 2 and I, and the sliver supply mechanism 4, this being shown as a lifter roll but it might be a creel or any other means of sliver supply as will later appear.

when the supply isdirect from the draw-frame cans, the sliver islifted therefrom by the lifter roll I and drawn by the pair of rolls A through the trumpet ion the traverse bar 6, thus entering the first stage. of the .draftfsystem. Essentially three draft stages are sufficient, the false 5 twist being applied to the middle stage, but a I of which may be arranged or related as pre- 1935, Serial No. 38.687

greater number of stages can be employed so long as the stage of greatest attenuation occurs in the initial or entrance side of the process and is immediately followed by the stage of draftplus-twist. In the present case the total draft process is divided-intoflve successive draft stages and the second of these stages is the stage of highest draft, being immediately followed as stated by the twisting stage.

The high or long draft stage can be carried out by any practical long-draft arrangement, of which several have been proposed, and that shown in, the machine taken for illustration operates according to the Casablancas system well known in the art. It comprises a pair of rolls with encircling belts B delivering to a pair of rolls C from which the stock passes to the third stage, represented by the rolls C and D with the twister head I intervening between them. The twister head comprises as usual a revolving tunnel and finger journalled on a frame support 8, and driven from a shaft 9 appropriately journailed above it, running parallel to the lines of draft rolls, the driving connections consisting of helical cut gears onthe twister head tubes and on the driving shaft 9. The latter shaft is covered by a casing l0 and the cap bars II, which support the top rolls, are arched, as shown at 12, to accommodate the shaft and its casing beneath them, thus rendering the twister mechanism easily accessible for maintenance purposes.

From the third draft stage, C-D, the stock enters the fourth stage DE and then the final stage represented by the rolls E and F. From the rolls F it passes to the flyer to be wound as roving on the bobbin in the usual way.

In applying the .principle of this invention the total draft of the system necessary for converting the given draw-frame silver to finished roving form is computed and then divided'so that the stagesfollowing the twisting stage each apply but a moderatev or normal amount of draft,- such for example as customary in roving frames, while the stage or stages preceding the twist. apply the rest of the draft necessary to bring the roving to the desired weight or hank size at the bobbin. This may be greater or less according to circumstances, but is always greater than the draft applied in any one or all of. the stages succeeding the twist'stage, the individual draftsferred for any particular case.

The advantages accruing from dividing the draft in this way, in a one-passage machine, are accounted for by the extremeslowness of action of the long-draft stage. I have observed that a certain time element enters into the emcient drafting of cotton which, if not allowed for, re-

sults in overstraln and possible rupture of some of the fibres, correspondingly impairing the yarn strength as shown by break-tests,--in other words, that individual fibres can be pulled away from a mass of fibres held by feed rolls with less strain when the pulling is done slowly than when it is done quickly. This assumption is confirmed by the well known tendency'of draw-frames and the like to snatch or pluck when over-speeded, the draft ratio remaining constant, and also the tendency of ordinary fiy and spinning frames, in which drafting is also done, to produce weaker yarn when the attempt is made to speed them up beyond a normal limit. By locating the long draft" stage, that is to say, the stage otherwise most likely to create the fibre damage referred to, on the entrance side of the draft process where the movement of the stock is extremely slow, a sufficient time element appears to be provided and is of course without effect on production rate. Rolls A and belts B in this location turn so slowly that their motion can hardly be seen. Rolls A for example turn at about 4 R. P. M. to serve a normal flyer speed of 1100 R. P. M. Belts B move only slightly faster. Under such conditions the fibres of the thick roving lightly held in the belts make a very leisurely approach to the bite of the next pair'of rolls, affording a sufilcient opportunity to them to straighten out and to some extent disentangle themselves by the efiect of their own elastic nature. in consequence of this action the resulting product spins, in the ordinary way, into a yarn more uniform and ordinarily stronger, count for count, than when the long-draft is otherwise applied, or even when the usual successive fly fram'e processes are em- 59 ployed according to conventional mill practice.

A series of comparative break-tests showed-a consistent improvement averaging about two percent. This improvement, coupled with the obvious economy inherent in a single-passage, roving-producing machine, makes this new process commercially desirable.

As a more specific explanation of the process it may be stated that the over-all draft ratio for the two stages A-B and 3-0, may range in practice from 5 to 12; for the third stage C to D from 1 to 2; and for the final stages D-E and E45, from 3 to 6: the total draft being from 15 to 80 according to circumstances and I the size and character of the roving desired. As will be observed in .the drawing, rolls A and belts B operate practically as-a singleroll, the drafting done between them being small say,

about 1.1 to 1.5, but it might in special cases "long-draft" stage on the entrance side of the twister.

As an example of what may be termed the preferred practice according to the process of this invention the following is given. A grain sliver is supplied direct from the cans. The total draft needed is determined to be 29.5 and is divided into stages as follows: 1st stage 1.10, 2nd

stage (long-draft stage) 6.32, 3rd stage 1.10, 4th

stage 1.10, 5th stage.3.50. This gives a 4.10

hank roving on the fiy frame bobbins which is then creeled on the spinning frame and spun with a final draft into 23s yarn in the usual way. It will be understood that the roll spacings are, set to accord with the staple length being in all cases. slightly longer than the average length as will be understood.

, The twister head speed is not critical, but a speed between and R. P. M. has been found satisfactory and produces the least lint.

The bottom rolls of the several draft stages are driven at the appropriate velocities by gearing located as usual at one end of the frame and covered by a casing indicated at I3- Incidental to the slower motion of the first draft stages, mechanical losses are substantially reduced as compared to those prior proposals of compound or multi-stage long-drafting where the longer drafts are applied in the later, higher roll-speed, stages. It is a fact that less power is required to drive the long-draft elements at slow speed than at higher, and by driving the belts B at the lower speed their useful life is correspondingly prolonged, which is an important factor in this class of equipment. Also by combining the longest draft with the slowest roll speed the development of lint is less than in the reverse arrangement because, as I have observed, speed in the attenuating step makes for lint production. The new machine is thus notably easy to keep in a clean condition, notwithstanding its high production rate.

. The most eflicient-form' of the invention conrequires to be traversed to the end that the wear on the following rolls shall be uniform. The traverse mechanism is not shown but it can have sufilcient amplitude to use the full lengths of the roll bosses without hindrance because of the special sequence of the draft stages above described.

I claim:

1. An improved drafting of stock in the manufacture of yarn comprising a series of draft-roll elements organized for drafting the stock in successive stages in a single passage therethrough, means for driving the roll elements of an initial stage to apply the major part of the total draft at such stage, such stage including a pair of draft belts, a

twister-head imparting false twist to the stock emerging from said stage of major draft and means for winding the product of the last stage on a bobbin.

2. An improved fly-frame for converting drawframe sliver into roving ready for the spinning frame comprising a series of draft roll elements organized for applying the whole of the required draft in a single passage and in successive stages.

means for driving the roll elements of an initial stage to apply the major part of the total draft,

said stage including a pair of drafting belts, a twister-head imparting false-twist to the stock The bobbins are machine for the multi-stage emerging from said major draft stage and a flyer m for imparting roving twist to the product of the last stage.

3. An improved fly-irame for converting drawframe sliver into roving ready for the spinning frame comprising a series of draft roll elements for applying draft in a single e in successive stages and including a pair of draft belts constituting an initial stage,- a twister-head for false-twisting the sliver between said draft-belt stage and a later stage and a flyer for imparting roving twist to the sliver of the final draft stage and winding it on a bobbin.

4. An improved fly-frame for converting drawthe cap bars, theiatter being'arched to clear said 10 shaft.

JAMES L. 'I'RUSLOW.

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