US2755514A - Speed frame drafting mechanism - Google Patents

Description

y 1956 J. NOGUE RA 2,755,514

SPEED FRAME DRAFTING MECHANISM Filed April 9, 1953 2 Sheets-Sheet 1 IZ GJ.

y 4, 1956 J. NOGUERA 2,755,514

SPEED FRAME DRAF'TING MECHANISM Filed April 9, 1953 2 Sheets-Sheet 2 42 40 a4 f4 a4 32 54 5Q J m 7 1 149. fie!!! 1 2L115 I 0/0505 RH liite SPEED FRANE DRAFTEN G MECHANISM Application April 9, 1953, Serial No. 347,807

Claims priority, application Great Britain January 15, 1953 7 Claims. (Cl. 19-130) The present invention appertains to a drafting process and mechanism for drawing a strand of fibrous material to make em therefrom.

This invention consists in a novel method and improved condenser means for obtaining longer draft in a single continuous operation and for producing a more regular and stronger roving or yarn.

A primary object of this invention is to prevent stretching of the sliver between drafts and avoid irregular displacement of the fibers. This object is attained by crowding the edges towards the center of the sliver and avoiding folding of the edges in towards the center so that the edges follow the shortest possible path between the hips of the drafting rolls and the holding rolls between drafting stages. Thus, concentration of friction on the edge fibers is eliminated since the edge fibers are incorporated directly into the mass of the sliver and are thereby given the support of the more numerous central fibers. This object is further attained by not interfering with the movement of the sliver in its path between the hips of the drafting rolls and the holding rolls, that is, by not deflecting the sliver from its natural path.

An embodiment of this invention is set forth in the following description and illustrated in the accompanying drawings, wherein:

Figure 1 illustrates the respective shortest distances which the marginal and the central fibers have to travel whilst the drafted sliver is being condensed.

Figures 2, 3 and 4 are diagrammatic illustrations showing how the path of the marginal fibers is lengthened by various ways of folding.

Figure 5 is a sectional side elevational view illustrating the new condensing means according to this invention in an operative position on a driven traverse bar between a rear pair of drafting rolls and afront pair of holding rolls.

Figure 6 is an elevational view of the inlet end of the condensing means.

Figure 7 is a cross-sectional view of a sliver showing the shape thereof and position of the edge fibers just prior to its entry into the condensing means.

Figure 8 is a cross-sectional view of the condensing means taken on line 8-8 of Figure 5.

Figure 9 is a cross-sectional view of the sliver showing the cross-sectional shape thereof and positions of the edge fibers at the portion of the condensing means shown in Figure 8.

Figure 1G is a cross-sectional view of the condensing means taken on line 10-10 of Figure 5.

Figure 11 is a crosssectional view of the sliver showing the cross-sectional shape thereof and positions of the edge fibers at the portion of the condensing means illustrated in Figure 10.

Figure 12 is a cross-sectional view of the condensing means taken on line 1212 of Figure 5.

Figure 13 is a cross-sectional view of the sliver showing the shape thereof and positions of the edge fibers at the portion of the condensing means illustrated in Figure 12, and

2,755,514 Patented July 24, 1956 Figures 14, 15 and 16' are cross-sectional views taken at longitudinally spaced points through a modified form of condensing means.

Many attempts have been made in the past to increase the total amount of draft which can be applied in the drafting systems of speed frames by introducing a con densing means between successive drafting stages so that the sliver which has been considerably expanded by a first drafting stage can be reshaped into a more compact strand ready for a subsequent drafting.

One typical example of these past attempts is illustrated in U. S. Patent 1,598,373 by L. Hemsley in which a false twist device is used. The principal disadvantages of this method are its cost and its mechanical complication. Another attempted solution to the problem is shown in U. S. Patents 1,738,796 and 2,238,659 by W. G. Reynolds in which the sliver is reformedbetween drafts by opposing tongue and grooved rolls that are disposed in vertically offset relation to the preceding draft rolls to deflect the sliver from its natural path and to hold the sliver from vertical and transverse expansion in co-operation with the preceding draft rolls; the tongue and grooved rolls fold the sliver by turning the edges over towards the center. This arrangement also has disadvantages and, like the method proposed by Hemsley, has been discarded throughout the spinning industry in favor of a system using a stationary condensing means, that is, a means which is stationary as far as the direction of travel of the textile material is concerned; the condensing means does, of course, normally have a lateral traversing movement.

These stationary condensing means can take a great variety of forms, and many types have been known in the trade for a considerable number of years, but those used hitherto can be classified broadly in two main categories. One category comprises those in which the sliver is condensed by travelling under tension against surfaces, that is to say, the sliver is made to pass over surfaces which deflect it from its natural path between the hips of two successive pairs of rollers generally in such a way that the edges of the sliver are folded over and inwards towards the center. The second category consists of those condensing guides or trumpets which simply push the selvedges towards the center but do not deflect the strand from its natural path. A characteristic difference be tween the results obtained by these two types of condensers is that with those in the first category at definite and predetermined form of folding takes place in a constant manner, whereas with the condensers in the second category, the folding which occurs due to the selvedges being pushed inwards to the center by the side surfaces of the condenser is essentially of an erratic character. In other words, the edge of the strand may fold up or down and the amount of folding may be of different magnitude according to the influence of many random factors in the flow of the material. The important point is that folding of some kind takes place in both kinds of condensing means which have so far been known.

The greatest difiiculty in condensing a textile strand between subsequent drafts in this way is to avoid producing irregularities. The rather loose material, which is fed into the machine, is in a very weakened form after the first draft has taken place. The introduction of a condenser makes it necessary in practice to have a fairly wide gap between the pairs of rollers preceding and following it, which means that the already drafted material is extremely vulnerable over this wide distance. The inherent weakness of the strand of material at this point is clearly demonstrated by the absolute necessity which has been found in practice of having some draft in this condensing stage and also by the fact that it is impossible to increase this draft above an extremely small minimum. The draft is necessary because the slightest friction against the surfaces of the condenser inevitably stretches the material and the strand would consequently sag and tend to accumulate in front of the condenser. On the other hand any draft above the absolute minimum necessary to avoid sagging would result in very irregular displacement of the fibers, because owing to the low degree of interfiber cohesion there would be a stretching or tearing of the weakest parts of the sliver, and such local rifts in the material would, of course, have an extremely damaging effect on the yarn quality.

On careful examination of this aspect of the problem it becomes apparent that the greatest stretch will take place at the edges of the strand because, amongst other reasons, these are the weakest parts. At the same time, for this very reason it is more undesirable that the stretching should take place here since there is less inter-fiber control and consequently more risk of irregularities being made. This tendency for the greatest amount of stretching to take place precisely where the material is most likely to tear is aggravated by a further factor. As already indicated after the first drafting stage on the speed frame, the thick material fed into the machine has been spread out into a ribbon which may be as wide as one inch or more. In the process of bringing the edges of this ribbon towards the center a further inevitable stretch takes place, quite apart from any which may be produced by the friction of the fibers passing over the surfaces of the condensing means because, as it will be realised, the shortest possible path of these marginal fibers is the hypotenuse CB of a right-angled triangle, Figure 1, of which one side AB is coincident with or at least near and parallel to, the center of the ribbon of material. The amount of stretch imparted to the marginal fibers by this alone has a value of nearly 2% It might seem strange that there can be any stretching of the edge fibers in relation to the central fibers of a sliver in view of the fact that the edge and the central fibers are taken up by a same pair of rolls and therefore at exactly the same speed. The direct result of the edge fibers having to follow a longer path than the central ones would be for the edge fibers merely to reach the nip of the take-up rolls later than the central fibers. This, however, would necessitate a longitudinal displacement of the edge fibers in relation to the central fibers and as all the fibers composing the sliver are considerably interlaced with one another the said displacement cannot take place without a certain interfiber action which consists in the edge fibers tending to hold the more central fibers back with them and, reciprocally, the central fibers tending to carry the e ge fibers forward with them. In practice, the result of all this is for the edge fibers to arrive at the take-up rolluip almost simultaneously with the central fibers which originally corresponded to the same sliver cross-section as those edge fibers. In other words, the edge of the sliver travels faster than the centre through the condensing zone and is therefore subject to some actual stretching.

it will be realised that if the edges of the strand are at all led over or under the center for purposes of folding, the path of the edge fibers becomes correspondingly longer, and so still more stretching of these edges will take place.

Figures 2, 3 and 4 illustrate diagrammatically how the path of the marginal fibers is lengthened by various ways of folding, the distance D being the value of the stretch or draft to which the edges of the sliver will be subjected.

A study of these factors leads to the conclusion that for best results it is imperative, firstly, to avoid folding so that the edge fibers follow the shortest possible path between the nips of the two pairs of rollers, that is to say, the condenser must ensure that there is no deflection of these fibers either up or down. Furthermore, the condensing means must be so designed that it avoids concentration of friction on the edge fibers where it would do most damage; instead, it must tend to incorporate the edge fibers directly into the mass of the strand in order to give those edge fibers the quickest and maximum support by cohesion with the more central fibers.

As shown in Figure 5, the condenser means 10 according to this invention is in an operative position on a driven traverse bar 12 of a roving frame, the other components of which have not been shown for the purpose of clarity, since their function and design are well understood in the art. The condenser 10 is located in a Zone of no substantial draft between the rear pair of draft rolls 14-14 and the front pair of holding rolls 16-16. It is understood that the sliver 18 is run through a plurality of pairs or groups of pairs of draft rolls, which are driven at successively higher speeds at attenuate the sliver, the draft rolls being coupled with the holding rolls in forming the drafting zones and being driven at higher speeds than the holding rolls. Thus, the draft rolls 14-14 receive the sliver from a pair of holding rolls (not shown) and impart a degree of attenuation to the sliver. The sliver 18 leaves the nip between the rolls 14-14 in a flattened condition. The spread out fibers of the flattened strand or sliver as it emerges from the rolls 14-14, are conducted through the condensing means 10 for the purpose of reassembling the fibers to restore the sliver into a compact form prior to its introduction to the nip between the rolls 16-16, thus insuring that there will be adequate inter-fiber cohesion for the subsequent draft between the holding rolls 16-16 and the drawing rolls (not shown) which co-operate with these.

The holding rolls 16-16 are driven at a slightly greater speed than the drafting rolls 14-14 to provide a tension draft on the sliver so that the sliver does not sag and tend to accumulate in front of the condensing means 10.

The condensing means 10 includes a condenser body 20, which is mounted on the traverse bar 12 in a manner disclosed in my co-pending application Serial 178,301 filed August 8, 1950, and now Patent No. 2,683,290, and is moved by the traverse bar. The condenser body 20 has a sliver passage 22 therethrough in alinement with the nips of the pairs of rolls 14-14 and 16-16. In cross section a preferred form of the passage is that of a rhombus or diamond in which the high central portion of the passage 22 is intersected by a vertically disposed longitudinally extending slot 24 in the condenser body, the slot being preferably of constant depth and uniform width from end to end of the body. The slot 24 has a bottom wall 26, which lies well below the natural path of the sliver 18 between the nips of the rolls 14-14 and 16-16 and which is so disposed as to be out of contact or engagement with the sliver, as it passes through the passage 22. The bottom wall 26 lies below the passage 22 so that any piece of broken leaf or other impurity brought in by the strand will be less likely to clog the passage. The slot 24 opens through the top wall of the condenser body, so that the sliver 18 may initially be entered or threaded into the passage 22 through the open mouth of the slot 24 instead of having to be threaded lengthwise through the passage 22. The inlet end of the passage 22 is preferably wider than the sliver so as to prevent any rufiling of its edges.

As illustrated more particularly in Figure 6, which is an elevational view of the inlet end of the condenser body 20 and in Figures 8, l0 and 12, which are cross sectional views taken of the body at longitudinally spaced points, the passage 22 converges in a horizontal sense from the inlet end 28 of the body to the outlet end 30. Thus the passage 22 includes the central portion 23 of the slot 24 above the bottom wall 26 and below the open upper end thereof, which central portion of the slot 24 contributes with the higher center portion of the rhombus or rhomboid passage 22 to form a relief portion of the passage for accommodating the central part of the sliver as it increases in thickness incident to its passage through the condenser as it is progressively narrowed due to the convergence of the side edges of the passage 22 from entry to exit ends of the condenser.

The passage 22 is composed of substantially triangular side portions 32 and 34 with their apexes disposed outwardly and their bases intersecting centrally and vertically in the central part of the slot 24. Thus the passage 22 has a central high relief portion, which is defined by the central portion 23 of the slot 24 and side portions 32 and 34, which converge toward the outlet end 39 of the condenser body 20. The side portion 32 of the passage includes a top wall 36 and a bottom wall 38 which walls converge toward a rounded apex side edge 40. The walls 36 and 38 of the side portion 32 diverge toward the relief portion 23 of the passage. The side edge 43 is rounded to avoid snagging stray fibers from the sliver and to insure that the selvedges of the sliver slide freely thereon. The side portion 34 includes a top wall 42, bottom wall 44 and rounded apex side edge 46, similar to the construction of the side portion 32. Thus, the side portions 32 and 34 are generally triangularly shaped, with their major or base portions open and communicating with the central portion 23 of the slot 24.

The passage 22 has its widest cross-sectional dimension at the entry end 28 of the condenser, from which end the side portions 32 and 34, progressively taper to the exit end 30 where the passage 22 has substantially merged with the slot 24. Viewed in top plan the passage 22 resembles an isosceles triangle with its base at the entry end 28 and its apex at or near the exit end 3%, the altitude of which triangle defines the relief portion 23 and the sides of which are formed by rounded side edges 49 and 46. In a sense transverse to the path of longitudinal movement of the sliver 18, the passage 22 may be considered at the inlet end as lozengeshaped and, due to the tapering of the side portions 32 and 34, which converge toward the outlet end 30 of the condenser body and finally merge in with the central portion 23, the passage at the outlet end has become substantially rectangular with its greater dimension in the vertical. In other words, the passage becomes narrower as it approaches the outlet end 30 of the condenser body and increases in the vertical dimension, so that the sliver 18 is allowed by the passage 22 to increase in thickness by just the required amount as the sliver becomes narrower. in this regard, it will be noted that the passage 22 at the outlet end 30 of the condenser body is substantially rectangular, since the convergent ends of the side portions 32 and 34 have merged with the side walls of the slot 24.

From a consideration of Figures 6 through 13, which illustrate the cross-sectional shape of the passage and also the cross-sectional shape of the sliver 18 as it moves through the passage, it will be noted that the sliver 18 comes from the rolls 1414 in a substantially flat, ribbon form. This is shown in Figure 7, wherein the selvedges or edge fibers are indicated by reference numeral 48. Following Figures 7, 9, 11 and 13, it will be noted that the edge fibers 48 are directly incorporated into the mass 50 of the sliver 18 thereby giving the edge fibers 48 the maximum support by cohesion with the fibers making up the central mass 50. The edge fibers 4-8, as the sliver travels from the rolls 1414, have little cohesion and tend to stand apart from the central mass 50. As the strand or sliver 18 enters the inlet end of the passage 22, the edge fibers immediately come into contact with the side edges 40 and 46 of the end portions 32 and 34 of the passage 22. There is no concentration of friction on the edge fibers but instead the edge fibers are immediately crowded toward the central mass 50, the progressive stages of such crowding being shown in the figures above referred to. Thus, from the flat, ribbon form shown in Figure 7, the sliver 18 progresses, due to the construction of the passage 22, to a substantially rectangular form at the condenser outlet 30. The sliver 18 enters the nip between the rolls 16-16 in this rectangular form so that the fibers are uniformly gripped across the entire section of the strand as the strand or sliver is compressed at the nip of the rolls 1616.

A modified form of condenser body 20' is illustrated by way of longitudinally spaced cross-sectional views in Figures 14-16, inclusive. It will be noted in comparing Figures 6 and 14, Figures 10 and 15 and Figures 12 and 16, that the condenser body 2% is formed with a passageway 22', which is similar in longitudinal and cross-section shape to that of the passageway 22. The condenser body 2% differs from the condenser body 26 in that the slot 24 is omitted so that only the passageway 22' is formed longitudinally through the condenser body. The sliver is thus initially threaded lengthwise through the passage 22. In cross section the passage 22' may be described as having generally the form of a rhombus or rhoinboid although variations of this geometrical form are permissible. In operation, the condenser body 23 functions similarly to the condenser body 26 in allowing the strand to increase in thickness by just the necessary or required amount as the strand or sliver becomes narrower.

With respect to the operation of both the condenser body 20 and the condenser body 20, it will be noted that the selvedges are not folded in towards the center, but that the selvedges or edge fibers are crowded into the central mass so that they are incorporated directly into the mass of the sliver. The condenser body is positioned, with respect to the straight or direct path of the sliver or strand, so that there is no deflection of the sliver or strand either up or down. That is to say, the sliver follows its natural path, without engaging any surfaces that would deflect it up or down. The central mass 50 is not directly acted upon by the condenser, the sole action of the condenser being to directly incorporate the edge fibers into the mass in an expedient manner, avoiding concentration of friction on the edge fibers and permitting the edge fibers to follow the shortest possible path between the nips of the rolls i i-14 and rolls Sui-16.

It will be noted that the side edges &0 and 46 approach an apex or point form, that is the condenser passage has little appreciable vertical height at such side edges where the selvedges of the sliver are engaged. As these side edges 46 and 46 exert a narrowing effect on the selvedges and the sliver generally, the fibers of the selvedges cannot be deflected either up or down, being prevented by the lack of appreciable height at the edge apex portions 49 and 46. The only effect of the tapering edge portions 49 and 46 is to move the selveclge fibers from opposite sides mutually inwards towards the center of the mass of the sliver. The walls 36, 38 and 42, 44 of the side portions of the passage 22 diverge inwardly both up and down from the apex edges 40 and 46 but this divergence does not permit of deflection of the fibers up or down out of their natural path of movement from nip to nip of the pairs of rolls 14 and 16, but only accommodates the vertical expansion of the sliver incident to the squeezing or crowding of its side portions centerward. Due also to the small vertical dimensions of the extreme outer side edge portions of the sliver passage 22, which portions converge from entry to exit end of the condenser and exert continuing forces on the selvedges throughout the passage of the sliver through the condenser, the selvedge fibers are moved horizontally inwards towards the central mass of fibers composing the sliver and therefore such selvedge fibers are required to take the shortest path and the path of least deflection into or toward the center fibers, thereby avoiding any concentration of friction on the edge fibers and incorporating the edge fibers directly in the mass of the strand by the shortest and quickest path, giving at the earliest period in the operation the maximum support by cohesion of the edge fibers with the more central fibers. The particular shape and form of the passage 22, 22 keeps the strand gently but suitably contained and folding of any kind and deviation of the strand are completely avoided.

It is to be understood that the terms and expressions which have been employed are used as terms of description and not of limitation and in the use of such terms and expressions, no exclusion of any equivalents of the features shown or described, or portions thereof, is intended since various modifications are possible within the scope of the invention claimed.

What is claimed is:

1. A condenser having a tapering sliver passage wide at its entry end to receive the sliver in flattened form and having side edge portions of small vertical dimensions to engage the fibers of the selvedges and move same substantially horizontally toward the central mass of the fibers without deflection, said passage being centrally of larger vertical dimension both upwardly and downwardly with respect to said side edge portions to accommodate the thickening of the sliver incident to its lateral compression.

2. A condenser having a longitudinally tapering sliver passage vertically narrow at its convergent side edges and of enlarging vertical cross-section both upwardly and downwardly with respect to said side edges and inwardly toward the center.

3. A condenser comprising a body having a converging sliver passage therethrough composed of substantially triangular side portions with the apex parts of the triangles outward and the bases of the triangles vertically adjacent one another, said body having a slot intersecting the base portions having a part extending below the central part of the passage and a part opening upwardly through the upper edge of the body, said slot running longitudinally with the passage.

4. A condenser comprising a body having a converging sliver passage therethrough composed of substantially triangular side portions with the apex parts of the triangles outward and the bases of the triangles vertically adjacent one another, said body having a slot intersecting the base portions having a part extending below the central part of the passage.

5. A condenser comprising a body having a converging sliver passage therethrough composed of apex side edges vertically thin throughout the length of the passage adapted to receive the selvage edges of the sliver and to crowd such edges toward the center as the sliver progresses through the condenser, pairs of divergent upper and lower walls extending mutually inward from the op posed apex side edges with the lower walls descending from the apex side edges to the center portion of the passage and the upper walls rising progressively from the apex side edges to the central portion of the passage to provide a vertically high central passage portion to receive the vertically expanding sliver as the selvage edges are condensed toward the central part of the sliver.

6. A condenser comprising a body having a converging sliver passage therethrough composed of apex side edges vertically thin throughout the length of the passage adapted to receive the selvage edges of the sliver and to crowd such edges toward the center as the sliver progresses through the condenser, pairs of divergent upper and lower walls extending mutually inward from the opposed apex side edges with the lower walls descending from the apex side edges to the center portion of the passage and the upper Walls rising progressively from the apex side edges to the central portion of the passage to provide a vertically high central passage portion to receive the vertically expanding sliver as the selvage edges are condensed toward the central part of the sliver, said condenser body having a slot extending wholly below the passage and opening upwardly into the lower portions of the progressively descending lower passage walls.

7. A speed frame comprising a pair of drawing rolls, a pair of holding rolls driven at slightly greater speed than the drawing rolls to place a small draft on the sliver moving between the nips of the two pairs of rolls, and a condenser between the two pairs of rolls having a sliver passage in alignment with the nips of both pairs of rolls, said passage being tapering substantially from inlet to outlet end and composed of rounded apex side edges and pairs of triangular upper and lower walls diverging mutually from the apex side edges to the central portion of the passage with the lower walls progressively descending from the apex side edges to the central portion of the passage to afford relief to the central portion of the sliver as the side edges of the sliver are condensed mutually centerward as the sliver progresses through the tapering passage.

References Cited in the file of this patent UNITED STATES PATENTS 1,313,164 Casablancas Aug. 12, 1919 1,499,607 Dawson July 1, 1924 2,079,122 Lawton May 4, 1937 2,272,787 Bentley Feb. 10, 1942 2,430,611 Gwaltney et al. Nov. 11, 1947 2,595,855 Jackson, Jr. May 6, 1952 2,618,023 Keene Nov. 18, 1952 FOREIGN PATENTS 682,208 Great Britain Nov. 5, 1952

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