US3006037A - Resilient top roll and nippers for drawing frames of spinning machines - Google Patents

Description

Oct. 31, 1961 A. R. BETT 0 3,006,037

RESILIENT TOP ROLL AND NI RS FOR DRAWING FRAMES OF P NNING MACHINES Filed 11 21, 1958 United States Patent RESEIENT TOP ROLL AND NIPPERS FOR DRAW- ING FRAMES 0F sPlNNlNG MACHINES Aroldo Roberto Bettolo, Novara, Italy, assignor to S.p.A. Oificina Meccanica SantAndrea Novara, Novara, Italy Filed Apr. 21, 1958, Ser. No. 729,604 Claims priority, application Italy Apr. 29, 1957 4 Claims. (Cl. 19142) This invention relates to textile fibre drafting rolls.

The use of resilient textile fibre drafting rolls, more particularly top rolls, in drawing frames for a spinning machine, has been repeatedly proposed; however, none of the numerous constructions could be successfully employed in practice.

It has been proposed to provide top rolls with a resilient covering, i.e. a cylindrical skirt of relatively large thickness and elasticity. Since the guiding of the fibres, particularly the lateral fibres, of a sliver was found to be insufficient, clearances were left within the relatively thick skirts or resilient material, of a form such as to remain unaltered under the action of weighting in respect of form and size in an axial direction.

According to a further proposal, a resilient intermediate body provided with a leather or rubber coating was secured to the roll core. This intermediate resilent body could comprise, according to this further proposal, a circular brush of thin wire or a brush fitted with animal or vegetable bristles. Finally, it was further proposed to make up the intermediate body of spring plates in the form of barrel staves.

It is further known to provide resilient top rolls with lateral rings adapted to absorb the weighting required for safely producing the required rotational cooperation with driven bottom rolls so that the pressure exerted by the resilient body on the fibres of a sliver being passed through the nip of a pair of cooperating rolls in a draw ing frame is not affected by weighting. In known top rolls of this kind, the resilient body is securely positioned between the lateral rings. The resilient material of the body clamped between the lateral rings, since it cannot yield axially under weighting, is undesirably crushed. This results constantly in an uneven distribution of the nipping pressure and, as a rule, in an insnflicient nipping of the edge fibres of a sliver. The change in passage of the sliver, of which the provision is desirable in all drawing frames, cannot therefore be employed when top rolls of the last described type are used on account of the irregular distribution of pressure. On the other hand, if the sliver always travels at the same point, the top roll of the feed roll or delivery roll becomes after a short period of use useless.

Finally, it has been proposed to use, instead of lateral rings, a hollow resilient skirt provided at both ends with protecting plates made of the same material as the skirt. However, experiments carried out with resilient rolls of this type, disclosed that the distribution of the nipping pressure becomes still less even.

In other known top rolls, a resilient sleeve of cylindrical shape is fitted on the roll core which is provided with lateral rings. In this case the sleeve bears on the rings, leaving a clearance between the roll core and sleeve. In this proposed embodiment, weighting does not alter the form of the sleeve.

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The resilient nipping is but small and almost always insufficient. Moreover, the nipping pressure is heavier in the middle than at the sides of a sliver being passed through the nip.

It is an object of the present invention to overcome imperfections and drawbacks ascertained in practical use of resilient top rolls known heretofore, and to provide the roll with a body made of resilient material capable of freely expanding under the action of weighting in an axial direction, so that a uniform nipping pressure can be applied on to a sliver throughout the width of the nip.

According to the present invention there is provided a textile fibre drafting roll comprising a core having a pair of rings or ribs provided around, and axially spaced from one another along, the core, and a sleeve of resilient material mounted "around the core. The sleeve has a part extending over the rings, the inner diameter of this part is larger than the outer diameter of the rings or ribs, so as to be normally out of contact with the periphery of the rings or ribs. The sleeve is such that, when the roll is brought into rolling contact with a counter-pressure device for the pressing therebetween of a sliver of textile fibres, the rings or ribs are able to engage the sleeve in the area of contact and the portion of the sleeve interjacent the rings or ribs is able to cooperate with the counter-pressure device in the rolling and pressing of the sliver.

For a better understanding of the invention and to show how the same may be carried into effect, reference will now be made to the accompanying drawings in which:

FIGURE 1 is an elevation view illustrating a resilient top roll associated with a fluted bottom cylinder, a part of the top roll being shown in section,

FIGURE la is a cross-sectional View of FIGURE 1,

FIGURE 1b is a similar view to FIGURE 1, the arrangement comprising atop roll of modified construction,

FIGURE 2 is a similar view to FIGURE 1, the arrangement comprising a modified cooperating bottom roll device with an elastic belt.

FIGURE 2a is a cross-sectional view of FIGURE 2,

FIGURE 3 is a similar view to FIGURE 1, the arrangement comprising a further modified bottom roll, similar to the top roll,

FIGURE 3a is a cross-sectional view of FIGURE 3,

FIGURE 4 is a view similar to FIGURE 1, the arrangement comprising a still further modified cooperating bottom roll device, and

FIGURE 4a is a cross-sectional view of FIGURE 4;

In the drawings, corresponding parts of the figures have been given the same reference numerals.

Referring to FIGURES 1 and 1a, the top roll comprises a core 1 provided with lateral rings or collars 2 and 2. A cylindrical sleeve 3 made of resilient material, as for example, oil-proof synthetic rubber, is fitted on the core, the inner diameter of the sleeve being larger than the outer diameter of the collars. The end portions of the sleeve 3 are inturned 4 and 4' and rest at their ends against the outside of the collars 2 and 2'. The sleeve 3 thus envelops the collars. When the top and bottom rolls are disengaged, a circumferential clearance 5 is left between the core 2 and the sleeve 3, but upon the top roll being loaded to bear against a fluted bottom roll or shaft 6, the clearance 5 is reduced in the region of rollto an extent such that the sleeve is pressedagainst the periphery of the collars 2 and 2'.

When the sliver f of textile fibres is passed between the nip of the cooperating top and bottom rolls, the thickness of the sliver causes the middle portion of the sleeve interjacent the collars 2 and 2' to yield farther radially inwardly towards the core 2 while the rings pinch the adjacent portions of the sleeve against the bottom roll 6. The pinching action of the collars thus prevents parts of the sleeve being drawn axially past the collarstowards thecenter by the tension induced'inthe middle portion of the sleeve bythe sliver f. The yielding movement of the middle portion of the sleeve towards the core is therefore dependent on the ability of the sleeve material to stretch. The nipping pressure exerted by the middle portion ofv the sleeve can also, therefore, be predetermined and is chiefly dependent on the hardness, resiliency, and diameter of the sleeve. The pressure exerted on the sliver by the middle portion, which. in efiect constitutes the working width of the top roller, is further uniform between the rolls.

Once the sleeve is pinched between the rings and bot tom-roll, increased pressure on the top-roller against the bottom roll cannot affect the nipping pressure of the sleeve on-the sliver.

Asshown in FIGURE 1a, the middle portion of the sleeve yields in accordance with the curvature of the bottom rollso as-partly to encircle the latter over the arc a-b. The yielding of the middle portion of the sleeve towards the axis of the core being of course greatest where the sleeve'intersects the planecontaining the axes of the top and bottom rolls. The-nip betweenthe top and'bottom rolls istherefore constituted by a curved area, which affords amore efiicient guide for the fibres of the sliver f therebyincreasing the drawing efficiencyof the-drawing mechanism. Uniformity of nipping pressure throughout theoperative width of thenip can be easily ascertained andmeasured by the resistance opposed to a thin thread or athin strip in various parts of the nip during drawing. Generally, the lateral fibres of a sliver are guided in a particularly efiicient manner through the illustrated device.

In FIGURE 1b, the inturned edge portions of the sleeve 3 of FIGURE 1 have been replaced by annuli 7 and 7' made of the same material as the sleeve or made of soft resilient material, for example sponge rubber, or consist ing-of resilient tubular rings. The annuli 7 -and-7 may either be. firmly secured-to-the sleeve or may consist of movable rings. In the latter case, it is; desirable to secure them against axial displacement;

For most practical requirements, the arrangement shown in FIGURES 1 and 1a and the arrangementshown in FIGURE 1b, which arrangements have'a plain bottom roller or shaft, will-be sufficient.

In FIGURES 2 and 2a, the top roll is similar to the top roll of FIGURE 1. The bottom roll 6, however, is formed with a portion 6' of reduced diameter beneath the middle portion of the sleeve 3, which reduced portion serves to accommodate and guide a belt 8-made of soft and resilient material such as sponge'rubber or the like. The outer surface of the belt may be covered with a thin s ip of rubber, leather or the like. The radial walls of the portion 6' also serve to improve the guiding and control'of the fibres of a sliver passed through the nip.-

In FIGURES 3 and 3a, the bottom roll 6" has lateral rings 2" and a resilient. sleeve having inturned end portions so thatv the top and bottom rolls have similar construction, features. This arrangement considerably enlarges the nipping surface (see FIGURE 3a) as compared with the nipping surface of: either FIGURE 1a or FIG- URE 2a.

It:will of course be understood that the-bottom roll may, have construction, featuressimilar. to those of the top roll shown in FIGURE 1b.

FIGURES 4 and 4a illustrate a further alternative arrangementcomprising a top rollof similar construction to the top roll of FIGURE 1. The top roll 1 co-operates with a counter-pressure device comprising a bottom roll 6, a belt reversing or guide bar 10 located forwardly of the roll 6 in the direction of movement of the sliver, and a belt 9 adapted to travel over the roll 6 and the bar 10. The top roll 1 is arranged to bear principally on the belt 9 between the roll 6 and the bar 19 thereby obtaining greater resilience. Such an arrangement affords a particularly large nipping surface as shown in FIGURE 4a. This arrangement. moreover advantageously reduces the nip space between the draft rolls and control rolls.

In 'anarrangement of this kind, it will be appreciated that the position of the top roll andof its bottom roll or cooperatingdevice may be interchanged.

What I claim is:

1. In a drafting apparatus for drafting sliver and the like, in combination, a pair of elongated members at least one of which comprises a roll, said members having in operation relatively moving peripheral surfaces. c0- operative in forming in operation a drafting zone between them, said members being disposed parallel and radially disposed relative to one another, said roll having a core provided with axially spaced collars fixed thereon for rotation therewith, a resilient sleeve disposed extending axially over said core for rotation with saidroll with opposite ends disposed axially outwardly of the collars, said sleeve having an inner diameter greater than the diameter of said collars and portions thereof radially adjacent said collars radially spaced from said collars, and in operation said collars'being disposed relative the other of said elongated members in position for bearing on corresponding portions of the sleeveradially adjacent thereof and causing said portions to bear on said other member thereby defining the width of the drafting zone along an axial length of the members intermediate the collars.

2. Ina drafting apparatus for drafting sliver and the like according to claim 1, in which said members include a driven apron cooperative with said sleeve on said roll in defining the drafting zone.

3; In a drafting apparatus for drafting sliver and the like; in combination, a pair of elongated members at least one of which comprises a roll, said members having in operation relatively moving peripheral surfaces cooperativein forming in operation a drafting zone between 1' them, said members being disposed parallel and radially disposed relative to one another, said roll having a core provided with axially spaced collars fixed thereon for I ing on corresponding portions of the sleeve radially adjacent thereof and causing said portions to bear on said other member thereby defining the width of the drafting zone along an axiallength of'the members intermediate the collars, and a traveling belt traveling over said other member between it and said roll along the zone intermediate thecollars of said roll.

4. In a drafting apparatus for drafting sliver and the like, in combination, a pair of rolls having in operation relatively moving peripheral, surfaces cooperative in forming in operation a drafting zone between them, said rolls being disposed parallel and radially disposed relative to one another, one of said rolls having a core provided with axially spaced collars fixed thereon for rotation therewith, a resilient sleeve disposed extending axially over said-core with opposite ends disposed axially outwardly of the collars, said sleeve having an inner diameter greater than the diameter of said collars and portions thereof radially adjacent said collars radially spaced from said collars, and in operation said collars being disposed relative the other of said rolls in position for bearing on corresponding portions of the sleeve radial-1y adjacent thereof and causing said portions to bear on said other roll thereby defining the Width of the drafting zone along an axial length of the members intermediate the collars.

References Cited in the file of this patent UNITED STATES PATENTS Pfiimlin June 9,

Pflimlin June 9,

FOREIGN PATENTS Great Britain July 10,

Great Britain Oct. 5,

Great Britain May 11,

France May 26,

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