US2498364A - Arrangement for - Google Patents

Description

Feb. 21, 1950 H. FRASER 2,498,364

ARRANGEMENT FOR DRAFTING AND TWISTING FIBROUS MATERIAL IN SPINNING FRAMES Filed June 29, 1948 3 Sheets-Sheet 1 Fla. 4

My. I lh /h/mm div/M Feb. 21, 1950 H. FRASER ARRANGEMENT FOR DRAFTING AND TWISTING FIBROUS MATERIAL IN SPINNING FRAMES 3 Sheets-Sheet 2 Filed June 29, 1948 Feb. 21, 1950 H, FRASER ARRANGEMENT FOR DRAFTING AND TWISTING FIBROUS MATERIAL IN SPINNING FRAMES 3 Sheets-Sheet 3 Filed June 29, 1948 Patented Feb. 21, 1950 ARRANGE ENT FOR DBAFTING AND TWISTING FIBRQUS MATERIAL 1 SP N NG F AM Hugh Fraser, Arbroath, Angus, Scotland, assignor to D u a er s L mit d, A br thl Angus, Scotland, a company of Great Britain an N orth n I d Application June 29, 1948, Serial No. 35,898 In Great Britain June 3, 1947 6 Cl ms.

inventi n r lates t imp ovemen s i errensement er raitin and twist n fib ous materi l i spinning f mes u i izi g i d f without causin une enn ss r ha riness of th It i d sirable thinni and wistin fibr o se a hi h draft beeause the a may th be made fr m a. ropo tionately hea r sli er- T e ier he. sliv r, e s ron and m re ea y ha dled it ill berandt e ne d fo in r due ng wist or crim in to a ist ha d n s lim Wi h a hi h draft mo e v i may be P i e t e eetin one un t th des e d e o a te uation for whic o or more machine units are required with normal drafts.

In converting into yarn a sliver-of fibrous mae a ic ay or may ne be twi ted, t e sp nnin r me e forms th e e sen al fu ctions: (1) the drafting or attenuating of the material from one weight per unit len th to a less weight per unit length, (2) the lateral condensing of the material so that the original compactness of the fibres is maintained, and (3) the twisting of the drafted and compact material so as to bind the fibres together and develop a considerable tensile strength. i

In k w high; d a in a ang nts draftin is effected by drawing fibres at a high speed by a pair of drawing rollers from a sliver retained at a lower speed by suitable means such as a pair of retaining rollers, in combination with breast plates, gill bars, carrier rollers, endless aprons or other intermediate devices.

The fibres delivered by the drawing rollers are twisted to form a yarn by revolving a yarn receiver and the yarn by suitable means. The operation of twisting, in addition to binding the fibres together in a permanent manner, performs also a greater or less proportion of the lateral condensation of the fibres, but the amount of condensing which can be achieved'by twisting is strictly limited. In other words, the fibres must be sufficiently condensed before leaving the drawing rollers to enable the twist to complete the condensing satisfactorily. If the fibres are not sufficiently condensed, a hairy yarn and excessive fly result, and this is a common defect experienced in high drafting.

The fibres may be laterally condensed before leaving the drawing rollers by interposing conductors between the retaining means and the drawing rollers. If, however, condensing in this way is overdone, some of the fibres are caused to be drawn in bunches or gulped, and production of irregular yarn results. This gulping appears 2 to be due to the fact that wherea at a point near he d aw rollers, whi h is e it al dra ting point, short fibres at the edges take a. curved path as they are acted on by the conductor, when a long fibre is seized by the drawing rollers, it at once ,straightens out and disturbs the neighbour.- ing short fibres, loosening them from the controlling means and causing them to move for.- wardat the high speed of the drawing rollers too early. This gulping, due to sudden condensing just before the drawing rollers, is another com,- on de ec o h h dra n Failure due to one or the other of these two call fis sets a definite limit to the length of draft attainable. This limit is markedly lower in drafting fibrous materials which have a great varia tion fibre length and a large proportion of short fibres.

The object of this invention is, therefore, to remove the two ses d r nder it pos ble to spin even very unfavourable materials, such as jute, from as heavy slivers as is desirable.

According to the invention, to effect delivery of the sliver from the retaining means tothe drawing rollers in a highly compacted form and narrow width so that drawing roller conductors, if us d, have the minimum work to do, while using one or th other of the known arrangements of two endless aprons between which the sliver is drawn, or of one endless apron and a slipper resting on the sliver being drawn, I provide lateral guides to confine the sliver and to effect con.- densins of he fi e s- In one embodiment of the invention applied to a drafting system comprising pairs of retain? in rollers and drawing rollers at the entrance to the nip of which lateral conductors are fitted, the reach or distance between the drawing and the retaining roller pairs is as usual slightly greater than the longest fibre of the material to be drafted. To control the shorter fibres in the drafting zone, i, e,., between the drawing and the retainingrollers, there is int rpos d an nd s flex ble apro driven at a speed only slightly in excess of that of the retaining rollers and serving to support the material on top of which rests a slipper, which may be weighted. The part of the slipper resting on the fibrous material constitutes a condensing surface for the sliver. The slipper is normally restrained from lateral movement by any conventional means (not shown).

The slipper may cover one or more slivers, and is provided with two lateral guides or confining surfaces for the sliver or for each sliver. These guides may extend lengthwise of the underside of the slipper, forming a channel in the latter, or, where the slipper covers only one sliver, it may be narrow, and guide plates confining the sliver laterally may be placed one on each side of it. The lateral guides, aforesaid, may extend the full length of the slipper or only part thereof. The guides, which form a channel on the underside of the slipper may rest on the apron; or the lateral walls of the channel, functioning as guide plates, may with the slipper enshroud a narrow apron.

Where two aprons are used, deep guide plates confining the sliver laterally may extend from a region above the lower flight of an upper endless apron to below the upper flight of a lower endless apron.

A substantially closed passage for the sliver is formed by the condensing surface of the slipper or upper apron, the confining surfaces and the carrying surface of thelower apron. This passage converges from the retaining rollers toward the drawing rollers over at least a portion of its extent. Consequently, during travel through this passage, the sliver is confined and laterally condensed.

The invention is illustrated in the accompanying drawings in which Fig. l is a side elevation of the drafting zone of a textile spinning frame incorporating one construction according to the invention. Fig. 2 is a view in the direction of the arrow A in Fig. 1 showing a slipper member. Fig. 3 is a cross section of the arrangement shown in Fig. 1. Fig. 4 is a view corresponding to Fig. 3 showing a modified form of the slipper member. Figs. 5 and 6 are views corresponding to Fig.; 3 showing arrangements of guide plates in conjunction with two aprons. Figs. 7 and 8 are elevations at right angles to one another showing a modification of the arrangement shown in Figs. 1 and 2. Figs 9 and 10 are elevations at right angles to one another showing a further modification.

Referring to Figs. 1-3 of the drawings, 20, 2| denote a pair of retaining rollers, and 22, 23 denote a pair of drawing rollers.

To control the shorter fibres in the drafting zone there is provided an endless flexible apron 26 which is driven at a speed only slightly in excess of that of the retaining rollers and which serves to support the sliver 3|. 2'! denotes a metal slipper of inverted channel form in cross section which rests upon the sliver 3i and is weighted at 28.

Fig. 4 shows a modification of the construction shown in Figs. 1-3 in which the sides of the slipper i. e. the flanges of the inverted channel 21', enshroud narrow apron 26b. In Fig. 5 a further modification is shown in which guide plates 40 are positioned at the sides of narrow apron 26' and above a broader lower apron 26". In Fig. 6 deep guide plates 39 enshroud both upper travelling apron 26a and lower travelling apron 26b.

Figs. 7 and 8 show a narrow slipper 31 at both sides of which are mounted upstanding stationary guide plates 38. Conductor 24 is mounted ahead of retaining rollers 20, 2| to properly position the fibres prior to the drafting operation. Slipper member 31 has an upstanding ridge 4| onto which the weight 28' is fitted. Guide plates 38 diverge at their upper ends to allow easy entrance of sliver 3i therebetween.

In the further modification shown in Figs. 9 and 10 there are provided lower and upper narrow aprons 26b and 26a, respectively, operating between deep guide plates 39. Conductor 24 positions sliver 3| prior to its passage between retaining rollers 20, 2 I.

What is claimed is:

1. Mechanism for drafting fibres in a textile spinning machine comprising retaining means, drawing rollers, a travelling apron for carrying the fibres from the retaining means to the drawing rollers, a condensing. surface extending in the direction of travel of and above the carrying portion of the travelling apron and converging toward said portion of the apron in the direction of travel thereof, a pair of confining surfaces 2. The mechanism of claim 1 in which the condensing surface and the confining surfaces are sides of a slipper of inverted channel shape in cross section.

3. The mechanism of claim 1 in which the confining surfaces extend downwardly at each side of the carrying portion of the travelling apron to below the upper surface thereof.

4. The mechanism of claim 1 in which the condensing surface is a'second travelling apron.

5. The mechanism of claim 1 in which the condensing surface is a second travelling apron which, during a portion of its travel, lies between the spaced confining surfaces.

6. The mechanism of claim 1 in which the condensing surface and the confining surfaces are sides of a slipper of inverted channel shape in cross section, and the slipper is wholly positioned above the carrying portion of the travelling apron.

HUGH FRASER.

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

UNITED STATES PATENTS Number Name D ate 1,448,191 Butler Mar. 13, 1923 1,448,192 Butler Mar. 13, 1923

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