US2890494A - Drafting mechanisms for textile processing machinery - Google Patents

Description

June 16, 1959 RAPER 2,890,494

DRAFTING MECHANISMS FOR TEXTILE PROCESSING MACHINERY I Filed Apri1 12, 1955 5 Sheets-Sheet -1 June 16, 1959 RAPER 2,890,494

- DRAFTING MECHANISMS FOR TEXTILE PROCESSING MACHINERY Filed April 12, 1955 5 Sheets-Shqet 2 G. F. RAPER June 1 1959 2,890,494 DRAFTING MECHANISMS FOR TEXTILE PROCESSING MACHINERY Filed April 1.2 1955 9 5 Sheets-Sheet 3 June 16, 1959 F, RAPER 2,890,494

DRAFTING MECHANISMS FOR TEXTILE PROCESSING MACHINERY Filed April 12, 1955 s Sheets-Sheet 4 June 16, 1959 RAPER 2,890,494

DRAFTING MECHANISMS FOR TEXTILE PROCESSING MACHINERY Filed April 12, 1955 5 Sheets-Sheet 5 United States Patent DRAcFTINiG'. MECHANISMSFQR TEXTILE PROCESSING MACHINERY George Frederick Raper, 'Masham, near "Ripon, England, assignor -to T.M.M. (Researcl1) Limited, Oldham, England Application April 12, 1955,.SeriaLNo. 500,943

'Claims priority, applicatiomGreat 'Britain April 15, 1954 9 Claims. (Cl. .19-7

The invention is concerned with the provisionof improvements in drafting mechanisms for textile processing machinery, more particularly (though not exclusively) for the processing of heavy substantially twistlessslivers .of worsted and other fibrous materialof analogous staple length, the object being to provide an improveddrafting mechanism incorporating means for detecting and correct- :ing irregularities in the thickness of the input sliver as suppliedand for controlling variations in thickness which may be produced by the drafting operation.

A drafting mechanism according to the invention com- ;prises in combination a detector sensitive to variations in thickness of the input sliver, said detector being located in advance of or being part of the drafting unit, means responsive to said detector for issuing signals which-are effective to govern means for regulating the draft so as to correct such variations, and -a conductor whereby the sliver, during its passage through the drafting field, is confined between surfaces and thereby constricted toless than its natural cross-sectional area for the major part of the zone wherein it is possible for any of-the fibres to be in'the gripof the drawing rollers, at least one opposite pair of such surfaces (conveniently surfaces lying above and below the sliver) being relatively adjustable in a direction substantially perpendicular to the sliver axis, and said conductor being stationary except that it may be'traversed laterally for the purpose of .distributing wear on the roller races.

The detector may be constituted byone of the pair of retaining rolls of the drafting mechanism or by one of a pair of rolls in advance of the retaining rolls, such detector roll being urged toward its companion roll and capable of moving in relation thereto in accordance with variations in thickness of the sliver passing between the rolls. The movements of the detector roll may .be amplified mechanically and caused to operate a relay by which corresponding signals are transmitted to means for regulating the draft introduced into the sliver.

The cross-sectional area to which the sliver must be "constricted at all points in its passage through the drafting zone, and the cross-sectional area of the conductor from point to point throughout its length, may be estimated from the ascertained fibre-length distribution 0f the material and the ratio of the ingoing and outgoing sliver thickness.

The conductorshould therefor possess a determined internal cross-sectional area from point to point estimated as above described, and for this purpose the internal surfaces of the conductor may either be fixed during the drafting operation so as to compress a sliver to less than .itsnatural or free cross-sectional area at any or all points, or they may be capable of relative movement in a direction normal to the sliver axis in accordance with variations in the thir-kness of the sliver. In the first case the condoctor may have internal surfaces the distance of which from, and the angle of inclination of which in relation to,

the sliver axismay'be fixed preparatory to drafting, such "surfaces being curved if necessary to securethe estimated change in internal-'cross-sectional area-of'the conductor. -In the-second case,-one' or more ofthe internalsurfaces' of the-conductor is-freely'movable andurgedyieldably in'a direction perpendicular -to "the sliver "axis, so that variations in sliver thickness alter *the internal cross-sectional area'of the conductor. In this-latter arrangement, 'the movable surface or surfaces may he "pivotable abouta fixed though adjustable'point, or the pivotitself maybe yieldablyurged'towards the sliver-axis. The pivotmay' be located so thatathick place inthe entering sliver expands the entry surfaces of theconductorandby contractingthe exit surfaces augments. the pressure onthe fibres which are in'the nip of'the drawing rollers, hence=morn'entarily increasing their drag-onthe'remaining fibres. Theloadon the yielding surfaces may be constant, so that the'pressure is independent of s'liverthickn'ess, or it may be such as 'to'increase the pressure directly as the sliver thickness. increases (or 'vice versa').

Itis desirable that the 'conductorshall'be solocated'that the'sliver axis follows -theshortest path through the drafting Zone, in 'order'to avoid the tendency towards variation-in sliver thickness which is brought about by a Lateral deviation from that path.

It will "beiappreciatedthat it maybe necessary in order to constrict the sliver to'les-sthanits natural or free crosssectional area, throughout the drafting zone, to use the conductor of the presentfinvention in those regions where there 'is in any eventa natural reduction in sliver cross:-

section, e.g. due tothe draftingaction, or 'to'the elastic nature of the sliver under variations in tension, or to the fact 'thataconstriction at a given point affects thesliver cross-sectional area .at adjacent rpoints.

The manner. of carrying the invention into efiect is hereinafter described with reference to the accompanying diagrammatic drawings which illustrate a preferred embodiment as designed for use'in processing worsted slivers.

Fig. 1 is a general side elevation of the apparatus, .partly in section to reveal the working parts of the transmitter mechanism, and Fig. 2 is a vertical section on the line 11-11 of Fig. 1. Fig. .3is an elevation of the conductor assembly shown separately .and Fig. 4 is 'an elevation .ing a modified .form of Worsted drawbox.

It will be seen by reference to Fig. -1 that the .lower upper retaining rolls of the drafting apparatus are indicated at 10 and 11, respectively, and the drawing rolls thereof at 12 .and 13, respectively. The fibre path (or sliver axis) is indicated by the chain-dotted line, extending through the drafting .field between said pairs of rolls; in its passage through such field, the sliver may be gripped by the .tongue-and- grooved carrier rollers 14, 15 and is subjected to the influence of the conductor unit which is indicated generally in this figure by the letter C. The constructional arrangement of the conductor is hereinafter described in greater detail with reference to Figs. 3 to .9.

The mechanism for detecting and corect-ing'irregularities of thickness of the inputsliverconveniently takes the form of the apparatus described and claimed in US. patent application S. N. 303,385, filed August 8, 1952, now Patent No. 2,746,093. The detector by which signals are issued to the drafting mechanism is constituted by the rollers '10, 11. The roller 10 is .grooved to receive-the periphery of the roller 11 which is mounted upon the arm 16 of a double-armed lever 16, 17 the pivotal movement of which about its axis (not shown) is effective to actuate a second double- armed lever 18, 19 through the cooperation of a bowl 171 carried by the lever arm 17 with a flat surface 181 ofthe lever arm 18. A weight 20, carried on an offset 21 of the lever 18, 19, serves to preserve working contact between the bowl 171 and the surface 181.

The upper end of the lever arm 19 carries the settingelement 22 by which corrective signals, proportional to the variations in thickness of the sliver, are transmitted to the mechanism employed to vary the draft of the sliver, and it will be seen that the setting-element lever 19 is displaced angularly from a datum position to a degree dependent upon the instantaneous displacement of the detector roller 11 in relation to the companion roller 10. The degree of displacement of the setting-element 22 is indicated by a pointer 23 which is atfixed to said element and the tip of which is arranged to move across a scale 24.

The mechanism incorporates a rod-wheel, that is to say a cylindrical cage comprising a double-flanged annulus 25 which is mounted on a shaft 26, the flanges of said annulus 25 being pierced by concentric rows of holes in each of which is received a rod 27 with capability of sliding freely therein with a minimum of frictional resistance. The shaft 26 is geared to the shaft 101 of the detector roller 10, from which latter the rod-wheel receives its drive. As the wheel rotates and the rods 27 are carried round, each rod in turn comes under the influence of the setting-element 22, which operates to vary the extent to which the rod projects at one end, i.e. towards the lefthand side as viewed in Fig. 1, by an amount which is a measure of the instantaneous thickness of the sliver between the detector rollers 10, 11. To enable it so to operate, said element 22 is fashioned with an arcuate portion 221 (Fig. 2) having converging terminal flanges between which the rods 27 are guided and which serve to displace the rods slidably in the anulus 25 in accordance with the angular displacement of the setting-element lever 19. Said portion 221 is capable of being adjusted in relation to the element 22 about the axis of the shaft 26; for this purpose the element 22 is sloted at 222 to permit of a suitable range of movement of the securing nuts and bolts 223.

The transmitter element which cooperates with said relay rods 27 consists of a plate 28 which is mounted upon a fixed pivot 29 in a position adjacent the periphery of the rod-wheel so that the under-surface of said plate rides upon the sides of the projecting parts of the rods 27 at one end thereof. An arm 30 integral with said plate 28 is arranged to bear by means of an adjustable setscrew 31 upon a tappet arm 32 which also is mounted on said pivot 29 and which rests upon the upper extremity of a push-rod 33. At its lower extremity said push-rod 33 is supported by an arm 34 integral with a lever 35 which is pivoted at 36 and which serves to operate means (not shown) by which the speed of the shaft 101 of the lower back drafting roller is regulated.

As the transmitter plate 28 rides over the sides of the rods 27 at their projecting ends, it is deflected about the axis of its pivot 29 to a greater or less degree dependent upon the algebraic amount by which each rod 27 in turn projects beyond the previous or succeeding rods. Were the input sliver being processed perfectly uniform in thickness, each rod 27 would project to the same extent and the angular displacement of the transmitter plate 28 would remain constant. In practice however it is found that the sliver thickness varies over a considerable range and a correspondingly wide range of movement of the transmitter plate 28 results; such movements are utilised to bring about the requisite variation in the speed of the roller 10 of the drafting unit which is necessary to eliminate the irregularity in sliver thickness to which the transmitter plate movement is due. As will be understood, the several operations of the apparatus are so timed as to take account of the period which elapses whilst a particular part of the sliver is travelling from the detector rolls 10, 11 to a point in the drafting zone between the rollers 10, 11 and the front rollers 12, 13.

After the rods 27 have travelled past the transmitter 28, they are re-set in a datum position by a stationary flanged guide-plate 36, the distance between the flanges of which is gradually diminished so that the ends of projecting rods 27 are pushed inwards to the common datum line by contact with the inclined inner surfaces of the flanges of the guide-plates 36 preparatory to coming under the influence of the setting element 22 at the next rotation of the rod-wheel.

The counterweight 37 which is fixed to the boss of the lever 35 imparts the requisite degree of pressure to the transmiter plate 28 upon the rods 27 and also prevents lost motion between the parts 32, 33 and 34. Centralizing weights 38 and 39 are carried by the levers 19 and 35. Springs may be substituted for any or all of such counterweights and centralizing weights, if desired.

The sliver conductor C, which is interposed between the drawing rollers 12, 13 and the carrier rollers 14, 15, is of such length as to extend rearwardly from a point near the front or drawing rolls 12, 13, to a point such that the passageway of the conductor causes the sliver to be constricted over the major part of the distance in which it is possible for any fibres to be within the grip of said front or drawing rolls, i.e. over a distance at least half the length of the longest fibres measured back from the drawing roll. Said conductor C is preferably located so that its mean longitudinal axis coincides with the line joining the nip-points of the retaining rolls 10, 11 and drawing rolls 12, 13, and it comprises two spaced side- plates 40, 41 and spaced top and bottom plates 42, 43 fitting closely between the side- plates 40, 41, the distance from and angle of inclination to the sliver axis of either or both of the top and bottom plates being adjustable. For example, the bottom plate 43 may be adjusted by means of cams 44 which are mounted for rotation by wheels 45 in slots 46 in the plate 43.

Alternatively, one side-plate and the bottom plate may be made integral and movable as one member, the top plate and the other side plate being likewise integral and adjustable as another member, or the top plate being held rigidly to the other side-plate during operation although capable of being freed and slidden upwardly to open the conductor for greater facility of threading the sliver.

In another embodiment of the invention shown in Figs. 5 and 6 the conductor may be capable of expanding or contracting automatically in a direction substantially perpendicular to the sliver axis in response to variations in sliver thickness, the conductor in such case comprising two spaced side- plates 140, 141 and spaced top and bottom plates 142, 143 closely but slidably mounted between the same, one or both of the top and bottom plates 142, 143 being loaded towards the other as by means of the spring-pressed levers 44a, 44a. Alternatively, either or each of the top and bottom plates may be held on a fixed but adjustable pivot at one point and loaded at another point, loading being effected by weights, springs or levers, or by a combination thereof. For example, in the embodiment shown in Fig. 9 the upper plate is divided into sections 242, 242, which are pivotally mounted in the side-plates at 45a, 45a and allowed to rest by their own weight upon the sliver passing beneath them. A similar yielding effect may be achieved by fashioning the sliver-contacting surfaces of the conductor from strips of Phosphor-bronze or other metal sheet, or other resilient material capable of yielding perpendicularly under pressure due to thickness variations of the sliver.

According to the further modification shown in Figs. 7 and 8, which is designed to accommodate thickness variations across the width of the sliver, e.g. in the case of a sliver which is naturally thicker along its centre-line than at its margins, the sliver-contacting surfaces 420 and 430 of the top and bottom plates 42a and 43:: may be made concave about the sliver centre-line, though not necessarily radial thereto, the degree of constriction of the sliver being controlled by suitably shaping the surfaces 420, 430 as exemplified in Fig. 7. Alternatively, said top and bottom plates may be divided longitudinally into two or more sections which are free to ride independently on transverse thickness-variations in the sliver.

In the arrangements illustrated in Figs. 1 to 9, the retaining rolls 10, 11 of the drafting apparatus serve also as the detector of the thickness-controlling mechanism. It will be understood that the function of the detector may be performed by an additional pair of rolls located in a position such that the sliver passes between them before reaching the retaining rolls of the drafting apparatus. Such an arrangement is illustrated in Figs. and 11 which shows the application of the invention to one form of worsted drawbox. In this machine, a sliver or number of slivers, passes over a guide 50, and then between a pair of rolls 51, 52 which serve to correct irregularities in the thickness of the sliver passing between them. The rolls 54, 55 constitute the retaining rolls of the drafting zone, and the rolls 56, 57 the drawing rolls thereof. On emerging from the nip of said rolls 54, 55 the sliver comes under the influence of the conductor unit C which is similar in constructional arrangement to the unit heretofore described with reference to Figs. 3 and 4.

The carrier rolls 14, 15, where such are provided, may have a positive nip to function as retaining rolls or merely operate upon the sliver with a pressure sufficient to impart a light nip, permitting long fibres to be pulled through. The rolls 14, 15 may be adjustable as to their position with respect to their distance from the sliver conductor C.

The improved drafting apparatus hereinbefore described is particularly suitable for use in the processing of heavy substantially twistless slivers, and is especially advantageous by reason of the fact that a wide range of draft values can be employed, according to the desired thickness of the output sliver. The high draft obtainable permits a low operating speed of the retaining rolls and a consequently high sensitivity to thickness variations in the input sliver, whilst the efiicient control of thickness variations due to the drafting action renders it possible to operate with a comparatively large fixed ratch, which is particularly advantageous when using means for detecting and correcting such variations.

The combined arrangement in a drafting apparatus, provided by this invention, of means for correcting irregularities in the input sliver and a conductor which may be adjusted as to its internal cross-sectional area in accordance with the fibre length distribution of the material to be processed and the ratio of ingoing to outgoing sliver thickness, yields results which hitherto have not been obtainable, since a sliver of more uniform thickness enables the conductor to control the fibres in the drafting zone more effectively, and also enables the optimum internal cross-sectional area of the conductor to be determined more accurately than would otherwise be possible. The estimation of the cross-sectional area of the conductor being dependent upon the fibre length distribution of the material and the ratio of ingoing to outgoing sliver thickness without due allowance for irregularity in the input sliver, it will be evident that the accuracy of the estimate must be affected beneficially by greater regularity of the sliver.

The form of draft-controlling device employed in accordance with this invention is advantageous because it does not cause lapping of the fibres as in apparatus employing moving or rotating draft-controlling means where by an increased load might be imposed upon the rolldriving mechanism and the variable-speed device; it can be used in conjunction with a wide range of thickness of slivers; and it permits a wide range of draft, whereby the output thickness of the sliver may be varied over a wide range.

What I claim as my invention and desire to secure by Letters Patent is:

l. A drafting mechanism for textile processing machinery, comprising a pair of retaining rollers and a pair of drawing rollers spaced therefrom, in combination, a detector sensitive to variations in thickness of the input sliver, said detector being located in a location between a position substantially in advance of, and a position between, said retaining rollers and said drawing rollers, means responsive to said detector for issuing signals, means responsive to said signals for regulating the draft so as to correct such variations, and a conductor composed of members which provide opposed pairs of surfaces whereby the sliver, during its passage through the drafting field is confined between surfaces and thereby constricted to less than its natural cross-sectional area for the major part of the zone wherein it is possible for any of the fibres to be in the grip of the drawing rollers, at least one pair of the opposed conductor surfaces being provided on distinct conductor members which are relatively movable in a direction perpendicular to the sliver axis.

2. Mechanism as claimed in claim 1, wherein means is provided for relatively adjusting the relatively movable conductor members in a direction substantially perpendicular to the sliver axis.

3. Mechanism as claimed in claim 2, wherein the relatively adjustable surfaces of the conductor are those lying above and below the sliver.

4. Mechanism as claimed in claim 1, wherein the sliver conductor comprises two spaced side plates, a top plate and a bottom plate, all assembled to enclose the sliver passage-way, at least one opposite pair of such components being relatively adjustable in a direction substantially perpendicular to the sliver axis.

5. Mechanism as claimed in claim 4, wherein the predetermined constriction of the sliver is obtained by appropriately shaping or curving the surface or surfaces in contact with the sliver of either or both of the top and bottom plates.

6. Mechanism as claimed in claim 4, wherein a component is mounted for pivotal movement.

7. Mechanism as claimed in claim 4, comprising means for resiliently operating upon one or more components of the conductor, to apply resilient pressure upon the sliver.

8. Mechanism according to claim 4, wherein the top plate and the bottom plate have sliver contacting surfaces which are curved in transverse cross-section.

9. Mechanism as claimed in claim 4, wherein one of the components of the conductor is divided into sections separately pivotable and allowed to rest by their own weight by the sliver passing in contact therewith.

References Cited in the file of this patent UNITED STATES PATENTS 1,132,316 Eves Mar. 16, 1915 2,407,100 Richardson Sept. 3, 1946 2,498,364 Fraser Feb. 21, 1950 2,681,475 Raper June 22, 1954 2,683,290 Noguera July 13, 1954 2,774,995 Sandelin Dec. 25, 1956

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