US2795010A - Means for producing a drawable staple sliver - Google Patents

Description

H. o. HESS 2,795,010

mus FOR PRODUCING A DRAWABLE STAPLE SLIVER I June 11, 1957 Filed April 9. 1953 INVEVNTOR. HEINRICH Orro Hess.

WLL M ATTUKNEK United MEANS FOR PRODUCING A DRAWABLE STAPLE SLIVER Application April 9, 1953, Seriai No. 347,728 Claims priority, application Switzerland April 10, 1952 5 Claims. (Cl. 19-556) Various methods and means have been proposed to transform a strand consisting substantially of endless filaments into a drawable staple fibre strand.

Because of their reliability and economical operation, severingdevices of the crimping or squeezing type have been found particularly suitable.

Many different devices have been used for restoring parallelism of the staple fibres which was disturbed by the cutting operation and for refinement of the mass of staple fibres .in subsequent operating stages. All, these devices, however, did not fully answer the requirements and account for the particularities inherent to the use of severing elements of the squeezing type.

Many synthetic fibres are welded together by the great specific pressure exerted by the edges of the cutters. The so produced tufts cause considerable difficulties during subsequent operations particularly at drawing operations. It is of primary importance to sever the particles, called fish-food, which hold the fibres forming a tuft together and to remove the particles from the layer of fibres. It has been proposed to arrange pairs of cooperating deeply stardiuted rollers between which the roving 8 Patent F coming from the cutter is pulled. The result, however,

difiiculties experienced with conventional arrangements by positively guiding the roving continuously produced by squeezing the filaments and subjecting the guided rovingalternately to a multistage forwardly and rearwardly acting combing and simultaneously to a drawing action and subsequently condensing the sliver to form a coherent strand. The invention also provides an apparatus for performing the method which apparatus comprises a conventional severing device of the squeezing type followed by a combing and drawing device which comprises a plurality of pairs of clamping rollers which are spaced according to the staple length; the apparatus also comprises pairs of needle rollers interposed between the clamping rollers, the speed of the'former at the needles being greater than that of the feed rollers but less than that of the delivery rollers, and means for condensing the staple fibre layer coming from the combing and drawing device and compressing the layer to form a compact strand.

The novel features which I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself however and additional objects and advantages thereof will best be understood from the following description of embodiments thereof when read in connection with the accompanying drawing in which Fig. 1 is a diagrammatic layout of the system according to the invention;

Fig. 2 illustrates a cut filament strand;

Patented June 11, 1957 I Fig. 3 is a large scale illustration of two different tufts of which the strand shown in Fig. 2 is composed;

Fig. 4 is a diagrammatic illustration of a modified drawing andcombing frame;

Fig. 5 shows a pair of needle rollers;

Fig. 6 is a diagrammatic side view of a condensing device;

Fig. 7 is a sectional viewof the device shown in Fig. 6, i

no sharp edges, the edges being flattened to a width of 0.3 to 0.5 mm. which is permissible because of the high specific pressure at which the edges are pressed against the surface of the counterroll, the dull edges reducing wear. The knives of the cutting roll may be arranged in single or multi-thread fashion, the circumferential spacing of the knives corresponding to the desired staple length. An elastic filling 4 is preferably provided between the knives to securely clamp the filament layer during the cutting operation and to prevent lateral displacement of the individual fibres. Other suitable cutters operating on the same rinciple may be used instead of the one described supra. A pair of clamping rolls 5 is placed proximately to the cutting device which rolls are followed by further pairs of clamping rolls 6, 7, and 8 at distances corresponding approximately to the length of the cut staple. Pairs of needle rolls 9, 10, and 11 are individually arranged between the pairs of clamping rolls. The needles 12 of the rolls are arranged in rows, the needles of one roll of a pair extending between the needles of the other roll of the same pair. Spacer rings 30 and 31 arranged at the ends of the needle rolls prevent contact between the needles of one needle roll with the surface of the opposed needle roll, see also Fig. 5. It has been found of advantage to place the needle rolls in each combing field immediately ahead of the delivery rolls of the combing field. The number of pairs of clamping and needle rolls may be greater or smaller than the number shown in Fig. 1, without departing from the scope of the present invention. The needle rolls are positively driven by conventional means, not shown. Other necessary drive means as well as the means for pressing the rollers of each pair against each other are all of a conventional nature and are therefore not illustrated.

A condenser 14 follows the drawing and combing device for condensing the spread out, cut, and combed filament layer 15 to form a roving of circular cross section. The latter is received in a compression device comprising a pair of feed rollers 16 and a compression chamber 17.

The filament layer 18, which is to be processed and which has previously been tensioned and spread to the desired width, is passed between calender rolls 19 to equalize the thickness of the layer before entering the cutter 1, 3. By squeezing the layer in the cutter at distances corresponding to the desired staple length, an incoherent staple fibre layer 20 is produced as shown in Fig. 2. As has been mentioned before, many synthetic fibres have a tendency to be welded together to form fibre tufts 21 (Fig. 3) due to the high pressure at which they are compressed in the cutter, the fibres of each tuft having a common particle 22 known as fish-food. The

ends of a bundle of fibres are frequently welded together in groups 22.

The fibre layer 20 composed of fibre packages or tufts of the type shown in Fig. 3 are gripped by the clamping rollers 5 whose distance from the cutter 1,. 3 is smaller than the staple length and whose drawing speed corresponds to the delivery speed ofthe. cutter. The rollers 5.

transport the roving toward the needle rolls 9.. The rolls of the next following pair of clamping rolls 6 rotate faster than the clamping rolls 5. The circumferential speed of. the needles 12 of the. needle rolls 9 is between the speed of the neighboring clamping rolls 5 and 6. This produces thorough combing of the fibre packages 21 held by the feed rolls 5 from both sides and beginning at the forward ends of the packages. The welded fibres are separated from the compression particles 22 and placed in parallel. relation, the particles 22 being dropped. As soon as the fibres have left the nip of the feed rollers 5, they are gripped by the delivery rolls 6 and pulled away at aspeed which is greater than the circumferential speed of the needle rolls 9. A combing effect is thereby pro duced also at the rear end of the fibres.

The above described process is repeated in the following combing fields whereby the cut staple fibre layer is positively guided, in contradistinction to conventional gelling devices, and alternately subjected to a forwardly and rearwardly effective combing action so that the fibre mass is refined in accordance with the draft in the individual combing fields. The .result is a hank which is clean and homogeneous, and in which the individual fibres are completely. separated and parallel. The removal of the squeezing residues or nips 22 eliminates formation of clusters in subsequent operations.

The number of needles 12 may be increased in the second andthird combing field to increase the combing efiect. Groups of two or more adjacent rows of needles may be arranged on the needle rollers, for example as shown in Fig. 4.

The circumferential speed of the needle rollers is adjusted closer to that of the feed rollers or of the delivery rollers, according to the result desired. It has been found advantageous to adjust the speed of the needle rollers in the first combing field similar to that of The fibre layer 15 leaving the combing and drawing device is incoherent and is fed into a device 14 which transforms the layer into a strand of circular cross section. The latter is pulled by a pair of rollers 16 into a compression chamber 17 where the strand is condensed or compressed into a staple fibre strand 23 which is suitable for transport and further processing. The finished strand may be packed into cans in the conventional manner.

Fig. 4 illustrates a modifiedcombing and drawing device. .An angular guide plate is provided between. the feed rollers 24 of the first combing field and the needle rollers 27. The guide plate 25 has a portion 26 proximal to the feed rollersand positioned substantially radially of i the lower needle'roller 27. The guide plate has a second portion 28 which is curved and shields the needles 29 of the lower roller 27 on a part of the circumference of the roller against the upper needleroller 27. In order to prevent contact of the needles of the two needle rollers 27 with the guide plate 25, the latter rests on spacer rings 30 and 31, whose outer diameters are greater than the diameters of the circles on which'the points of the needles are located. Effective interpositioning of the needle rows, in spite of the guide plate portion 28, is assured by arranging the spacer rings 30 and. 31 in axially staggeredrelation, as shown in Fig. 5. A similar 4. guide plate 32 may be provided also in the subsequent combing field, which guides the fibre layer in the described manner into the nip of the pair of rollers 33 which are provided with groups of three adjacent needle rows. The combs on the pair of rollers 33 are preferably made finer than the combs on thepair of rollers 27.

The staple fibre layer coming from the feed rollers 24 is diverted from its horizontal path and directed in substantially radial direction toward the lower needle roller 27, in contradistinction to the arrangement shown in Fig. I in which the fibres are directed into the nip and tangentially of the needle rolls. Combing of the forward ends of the individual tufts 21 is thereby improved. The combing effect is further intensified by the portion 28,0f the guide plate 25 which causes complete penetration of the tufts by the needles 29 of the lower roll 27.

Instead of the condenser 14 shownin Fig. 1 for concentrating the combed fibre layer 15, a device according to Figs. 6 and 7 is preferably provided, which comprises a forwardly pointed feed table or platform 34 whose sides are formed by endless belts 35 and 36 which are looped about vertical guide rolls 37, 38 and 39, respectively, and move in'the direction of the arrows shown in Figs. 6 and 7. The feed table is downwardly inclined between the guide rolls 37, 39 and 38, 40 -(Fig. 7) so that the direction of movement of the fibres on the table deviates from the direction of movement of the lateral belts 35 and 36. The velocity component of the latter in the direction of movement of the fibre material corresponds substantially to the speed of the feed roller pair 41 and to that of the feed rolls 42 of the compressing chamber 43.

Sliding of the fibre layer fed by the rolls 41 onto. the feed table 34 toward the roller pair 42 is assisted by the decline of the table. The layer is simultaneously compressed from the sides by the moving belts 35 and 36. Due to the relative position of the feed table and the lateral feed belts, the lateral portions of the web are raised relatively to the center portion of the fibrous web which assists rolling-in of the layer from both sides and rounding of the strand without tearing. By increasing or decreasing the speed of the belts a relative motion between the marginal portions of the fibre layer and the belts can be produced, if desired. Laterally projecting fibres can thereby be smoothed back into the layer.

The angle formed by the belts 35 and 36 is preferably to more obtuse angles cause too great relative speeds of the belts, whereas too acute angles impede sliding of the fibres ,due to the greater length of the feed table.

Fig. 8 shows a knife roller 44 one half of which. is provided with knife ridges arranged in left-hand threaded fashion and the other half of which is provided with knife ridges in right-hand threaded fashion. This produces a symmetric pattern of the cuts of the fibre layer which is indicated by dotted lines in Fig. 6 and which assist rolling the layer into a strand.

While I have shown and described specific embodiments of my invention, it will be apparent to those skilled in the art that various changes, modifications, substitutions, additions and omissions may be made therein Without departing from the spirit and scope of my invention as set forth in the appended claims.

What is claimed is:

1. An apparatus for transforming a layer of endless filaments into a draftab le staple fibre strand comprising, in combination, a severing device of the blunt cutting type, a pair of feed rollers receiving the severed filaments from said severing device, a pair of delivery rollers receiving the staple fibres from said feed rollers, the distance between said feed rollers and said delivery rollers slightly exceeding the staple length, a pair of superposed needle rollers interposed between said pairs of feed rollers and said pairs of delivery rollers for combing the staple fibres, the circtunferential speed of the needles of said needle rollers being greater thanthat of said feed rollers and smaller than that of said delivery rollers, a condensing device receiving the staple fibres from said delivery rollers, and a compressing device receiving the staple fibres from said condensing device for forming a coherent staple fibre strand, each of said needle rollers being provided with rows of needles, the rows of needles of one needle roller of the pair being consecutively interposed between the rows of needles of the other roller of the pair upon rotation of the rollers, said needle rollers being provided with coaxial spacer rings to prevent contact of the points of the needles of one needle roller with the other needle roller.

2. An apparatus according to claim 1, the radial extension of said spacer rings being greater than that of the needles, the rings of the needle roller of one pair being axially staggered with respect to the spacer rings of the other needle roller of the pair.

3. An apparatus for transforming a layer of endless filaments into a draftable staple fibre strand comprising, in combination, a severing device of the blunt cutting type, a pair of feed rollers receiving the severed filaments from said severing device, a pair of delivery rollers receiving the fibre material from said feed rollers, a pair of superposed needle rollers interposed between said feed rollers and said delivery rollers for combing the fibre material, guide means for the fibre material interposed between said feed rollers and said needle rollers and comprising a first guide portion deflecting the fibre material from a straight line between the nips of said feed rollers and of said needle rollers, said guide means comprising a second guide portion covering one of said needle rollers on a portion of its circumference, and a condensing and compressing device receiving the staple fibres from said delivery rollers and forming a coherent staple fibre strand.

4. An apparatus as defined in claim 3 comprising spacer rings on each of said needle rollers to prevent contact of the points of the needles of one needle roller with the other needle roller, said second guide portion having lateral portions adjacent to said spacer rings.

5. An apparatus for transforming a tow of endless fil'aments into a draftable staple fibre strand comprising, in combination, a severing device of the blunt cutting type, a pair of feed rollers receiving the severed filaments from said severing device, a pair of delivery rollers receiving the fibre material from said feed rollers and having a greater surface speed tlran that of the feed rollers, 21 pair of superposed pin rollers interposed between said pair of feed rollers and said pair of delivery rollers, the circumferential speed of the pins on said pin rollers being greater than that of said feed rollers and smaller than that of said delivery rollers, and condensing means disposed downstream of said delivery rollers with respect to the movement of the filaments, said condensing means including two vertical horizontally moving converging endless belts, and a pair of superposed horizontal rollers disposed adjacent to said belts where said belts are closest together, the nip of said horizontal rollers being lower than the nip of said delivery rollers.

References Cited in the file of this patent UNITED STATES PATENTS 2,142,475 Lohmann Ian. 3, 1939 2,249,083 Kern July 15, 1941 2,293,712 Campbell Aug. 25, 1942 2,43 8,469 Wilkie Mar. 23, 1948 2,492,306 Mackie Dec. 27, 1949 FOREIGN PATENTS 1,840 Great Britain of 1860 518,995 Great Britain Mar. 13, 1940 895,435 France Jan. 24, 1945

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