US3287768A

US3287768A - High speed cotton draw frame

Info

Publication number: US3287768A
Application number: US514494A
Authority: US
Inventors: Albertus Rakhorst
Original assignee: STOOMSPINNERIJ TWENTHE NV
Current assignee: N V Stoomspinnerij "twenthe"; STOOMSPINNERIJ TWENTHE NV
Priority date: 1961-01-04
Filing date: 1965-12-17
Publication date: 1966-11-29
Anticipated expiration: 1983-11-29
Also published as: CH396710A; BE611830A; GB947121A; NL114051C; NL259697A

Description

NOV. 29, A. RAKHORST HIGH SPEED COTTON DRAW FRAME 2 Sheets-Sheet 1 Filed Dec. 17, 1965 INVENTOR. /l/z5eri uJ [Fdk ho/ziC I BY MQ M;

1966 A. RAKHORST 3,287,768

HIGH SPEED COTTON DRAW FRAME Filed D60. 17, 1965 2 Sheets-Sheet 2 LI IVENTOR. ///Z)/'(,LLL6 ARA f, t

United States Patent Ofifice 3,287,768 Patented Nov. 29, 1966 3,287,768 HIGH SPEED COTTON DRAW FRAME Albertus Rakhorst, 'Nijverdal, Netherlands, assignor to N.V. Stoomspinnerij Tr'venthe, Stationsplein, Almelo, Netherlands, a Dutch corporation Filed Dec. 17, 1965, Ser. No. 514,494 Claims priority, application Netherlands, Jan. 4, 1961,

Claims. 19-200 This application is a continuation-in-part of application Ser. No. 150,393, filed November 6, 1961, now abandoned.

This invention relates to cotton spinning and especially to the removal of seeds, leaves and other vegetable impurities from cotton fibrous webs.

Certain types of raw cotton contain so many seeds, leaves and other impurities, that these impurities cannot completely be removed in the initial spinning stages such as opening and carding. Thus, it is highly desirable to take special measures for removing these impurities in later stages of the spinning process, as otherwise the cloth woven from the resultant yarn has an unacceptable speckled appearance from the presence of such impurities.

In wool spinning systems, it has been proposed to mount pairs of fluted rolls at the delivery end of sets of drawing rolls, for dividing foreign bodies within the wool into smaller particles by coaction of the teeth and grooves of the pairs of fluted rolls. This system is illustrated in Patent No. 2,509,148. This expedient cannot be used for cotton, however, since it is not technically feasible to make the teeth and grooves of the rolls sufliciently fine that they can efficiently act upon the relatively small impurities in a cotton web so as to cut such impurities into smaller particles. Moreover, due to the differences in fibre character, there is a serious likelihood of damage to the cotton fibres themselves by such treatment.

One of the prior procedures for removing such impurities from cotton fibres has been to mount a pair of heavy, smooth steel rolls at the delivery end of the carding engine employed in the spinning process and to press these rolls together with such force that the seeds and other impurities are crushed and pulverized to dust particles which drop out of the cotton web during further processing. However, this expedient is expensive, as well as unsatisfactory, because it requires the use of a pair of precision ground heavy rolls of high quality steel each having a diameter of about 3 inches and a length of about 40 inches and the production of a carding engine equipped with these rolls is, at most, about 40 pounds of cotton per hour.

Before this invention, to use a pair of smooth coacting pressure rolls at the delivery end of the sets of drafting rolls of a cotton draw frame, has not been considered practicable since the web leaving a draw frame is about 6 to 8 times thicker than the web leaving a carding engine and experience with the smooth crushing rolls on carding engines as described has taught that the web must be very thin, preferably in the order of 55 to 65 grains per square yard.

The present invention is based upon the discovery that very good results in the removal of foreign bodies can be obtained by smooth crush rolls on a cotton draw frame, even at high speed, if the conditions set forth hereinafter are observed.

It is an object of the invention to provide a high speed cotton draw frame comprising means for crushing and disintegrating seeds, leaves and other impurities in the processed cotton slivers.

A further object of the invention is to include in such a draw frame means for removing the crushed and disintegrated impurities from the crush rolls.

With these and other objects in view, as will hereinafter more fully appear and which will be more particularly pointed out in the appended claims, reference is now made to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a cross section of the upper part of a high speed cotton draw frame equipped with the crush rolls according to the invention.

FIG. 2 is a schematic View of an alternative arrangement of the draft rolls and crush rolls in a draw frame according to FIGURE 1.

FIG. 3 is a perspective view of certain parts of the draw frame according to FIGURE 1.

FIG. 4 is a cross section of details of the roll loading device.

The drawings show only the upper part of a high speed cotton draw frame, namely the part comprising the drafting apparatus since the other parts of the draw frame may be of conventional construction, a description of which is not necessary for an understanding of the invention.

The drafting mechanism of the draw frame is mounted within an enclosure, usually of sheet steel, comprising an upper part or cap 1 which can be swung upwards so as to provide access to the drafting apparatus, a bottom 2 and a pair of side walls 3, only the right side wall 3 being shown. Generally in a draw frame there are at least two such drafting mechanisms side by side and preferably each drafting unit has a separate enclosure so that for servicing one need only lift the cap 1 of a single unit. Thus, there would also be a second lateral wall not shown at the left of FIG. 3, and the cap 1 would only extend between the wall 3 shown and the corresponding wall at the left of FIGURE 3.

Within the space enclosed by the cap 1, the bottom 2 and the lateral walls 3, there are frame members, such as 4, for carrying the ends of a plurality of rolls which constitute the drafting mechanism. In FIGURE 3, a frame member 4 is shown at the right end of the drafting apparatus, but it will be understood that there will also be a corresponding frame member at the left end of said apparatus.

In the embodiment of FIGURES l and 3, there are three lower rolls 5, 6 and 7, each journalled in bearings not shown in the frame members 4 at both ends of each roll. The rolls 5, 6 and 7 have a central or operating portion of increased diameter, the operating portion of the rolls 5 and 6 being provided with longitudinal or helical grooves while the operating portion of the roll 7 has a smooth metallic surface, preferably of polished steel. Cooperating with the lower rolls 5, 6' and 7 are five

upper rolls

8, 9, 10, 11 and 12, each of said upper rolils being journalled on the frame member 4 by bearings at their ends of reduced diameter. In FIGURE 3, such a bearing 13 on the right end of roll 11 is shown, it being understood that the other bearings are of similar construction. The bearings 13 of the five

upper rolls

8, 9, 10, 11 and 12 rest in recesses 15'- in the upper face of the frame members 4 and are held therein by the action of a pivoted pressure arm 14 which will be described later. Upon moving upwardly the pivoted pressure arm 14, the

upper rolls

8, 9, 1t), 11 and 12 with their bearings 13- can be lifted from the recesses 15 of the frame member 4, as for servicing or replacement. The

upper rolls

8, 9, 10 and 11 have a central or operating portion of increased diameter which is preferably covered with rubber or like tough, resilient polymeric material. The central or operating portion of increased diameter of the upper roll 12 has a smooth metallic surface, preferably of polished steel.

The pressure arm 14 is pivoted on a shaft 16 which extends parallel to the rolls 5-12 and which is fixed at its ends in the side walls 3 of the draw f-name. There is,

of course, another pressure arm, not shown, for the other ends of the rods. Each arm 14 extends forward from the shaft 16, at a certain distance over the upper end of the frame member 4, and the foremost portion of each arm 14 is downwardly inclined in conformity with the downwardly inclinedhforemost portion of the upper part of the frame member 4. Referring more particularly to FIG- URE 4, this shows one of the recesses 15 of the frame member 4, and the associated lower face of pressure arm 14 which latter is provided with a box-like extension 17, containing a heavy spring 18 and a sliding pressure pin 19 loaded by the spring 18. Similar means are provided at each end of each of the several rolls.

The forward end of each pressure arm 14 carries a pivotally mounted L-shaped lever 20, 21, the part 28 of the lever extending in front of the front face of the arm 14 and the handle 21 extending laterally of and parallel to the foremost part of the arm 14. The lever 20, 21 pivots about pin 22 which is fixed to the front face of the arm 14. The part 20 of the lever carries a pivoting brace 23, which may be engaged behind a nose portion 24 of the front face of the frame member. The lever 20, 21 and the brace 23 form a toggle linkage so that by engaging the brace 23 under the nose 24 and moving the lever arm 21 rearward, toward the pressure arm 14, the latter is drawn toward the frame member 4-, and the pressure pins 19 of the extensions 17 of the pressure arm 14 thereby exert pressure on the bearings 13 of the upper rolls 8-12. The pivot pin 22 is so located with respect to the lever part 20 and the brace 23, that the brace 23 may be moved somewhat past the pin 22 for obtaining a self-locking position of the toggle linkage. Referring again to FIGURE 4, the bearings 13 are provided with a recess 25 in the area which engages with the pressure pins 19 so that when applying the presure arm 14, the pins 19 not only apply a downward pressure to the upper rolls 8-12 but also prevent rotation of the shaft portions of those rolls by engagement in the recesses 25.

The lower rolls 5, 6, 7 extend past the frame member 4, and through the lateral wall 3 into the casing at the far side of said wall, the lateral wall 3 forming part of said casing. Said casing contains gears and further drive mechanism, not shown, for driving the rolls 5, 6, 7 clockwise as indicated in FIG. 1, at relatively increasing circumferential speed, that is so that the roll (retaining roll) has the lower speed, the roll 6 (intermediate roll) has an increased speed, and the roll 7 (delivery roll) has a higher speed than the roll 6. The

rolls

8, 9, 11

and 12 are driven by surface contact with the rolls 5, 6, 7 so that they rotate counter-clockwise as indicated in FIG. 1.

The rear wall 29 of the enclosure of the drafting mechanism is provided with an aperture 26 through which extends a guide bar 27 over which a plurality of cotton slivers can be fed in known manner from a plurality of cans into the nip of the paired

retaining rolls

5, 8 of the mechanism. After passing the several rolls of the drafting apparatus, the slivers leave the front rolls 7, 12 as a unitary web, which is condensed by the trumpet 28 into a sliver, which passes through a hole 30 in the bottom 2 of the enclosure of the drafting apparatus to the coiler device, not shown, which is arranged in known manner below the bottom 2.

The

rolls

5, 6, 8, 9, 10 and 11 are provided with clearer bars or rubbers 31 which serve to clear the rolls from accumulated lint. The rubbers engaging the

upper rolls

8, 9, 10, 11 are mounted between the pressure arms 14 so that they are lifted together with the pressure arms 14.

In the bottom 2 of the enclosure of the drafting apapparatus, there is an air exhaust conduit 32 and in the lateral wall 3 there is an air exhaust conduit 33, both conduits being connected to a source of suction, whereas the lower edge of the front portion of the cap 1 is provided with spaced protrusions 34 so as to leave an air inlet slot of about /2" wide between the cap 1 and the body 2. When operating, the suction in 32 causes an air flow from the slot 35'past the several rolls to the

exhaust conduits

32 and 33, said air flow serving to pick up and carry away the accumulated lint.

With the exception of the front rolls 7 and 12, the apparatus so far described is of known construction. The known apparatus, however, in place of the rolls 7 and 12, is provided with a grooved lower roll cooperating with the rubber covered upper roll 11 which constitute the set of delivery rolls of the drafting mechanism. When operating the known machine, the slivers (usually 6 or 8 in number) entering via the aperture 26, are forwarded by the pair of retaining

rolls

5, 8 to the intermediate rolls 9, 6, which, rotating at higher speed, attenuate the set of slivers and forward them again in cooperation with the upper roll 10, and the pair of delivery rolls 11 with the aforesaid grooved roll replacing the roll 7 further attenuate the slivers once more, the slivers being also spread out laterally, so that at the nip of the pair of delivery rolls, there is a unitary web of cotton fibres, formed by the combination of the original set of slivers. After condensing of this web by the trumpet 28, the resultant sliver will have about the same count as one of the original slivers, taking account of the attenuation which has taken place in the drafting apparatus. The small fibres liberated from the web during the process are cleared from the rolls by the rubbers 31 and are carried away by the air flow toward the

exhaust tunnels

32 and 33.

According to the invention, the drafting apparatus contains means for crushing and disintegrating seeds, leaves and other vegetable small impurities which are present in the processed cotton slivers. This is done by the pair of smooth rolls 7, 12. The lower roll 7 of this pair replaces the conventional grooved lower roll of the set ofdelivery rolls of the conventional drafting apparatus and, as stated above, it has a smooth metallic surface, preferably of polished high grade steel. Although the roll 7 lacks the usual longitudinal grooves of lower rolls of drafting apparatus, it has been found that it can adequately perform the second attenuating step of the drafting process together with the upper roll 11. The roll 7 further cooperates with the upper roll 12 of similar construction for exerting a high pressure on the web, which, upon leaving the pair of delivery rolls 7, 11 enters the nip between the crush rolls 7 and 12. It should be noted that the roll 7 has both the function of delivery roll in combihation with the roll 11 and the function of crush roll in combination with the roll 12. The high pressure between the rolls 7 and 12 (caused by the spring 18 and the pin 19 acting on both ends of the roll 12) acts to crush the seeds, leaves and other small vegetable impurities in the cotton web and to pulverize them so that they become dust particles.

For efficient operation, the diameter of the operating part of the rolls 7, 12 is preferably greater than the diameter of the draft rolls, namely in the order of 2". Further, theforce with which the roll 12 is pressed on the roll 7, should be in the order of to pounds at each end. It will be appreciated that the rolls 7, 12 in view of their relatively small diameter and limited length (less than 8") are much cheaper than similar but bigger rolls at the delivery end of a carding engine, and moreover, the initial cost of these rolls only slightly increases the cost of spinning per pound of cotton in view of the fact that a draw frame of the type described can operate at a delivery speed of 800 feet per minute which means an output of about 240 pounds of cotton per hour. Even when using such crush rolls in both draw frames of two consecutive drafting operations in the spinning process the initial cost of this seed removing equipment adds very little to the spinning cost per pound of cotton treated.

FIG. 2 shows more-or-less diagrammatically an alternative arrangement of the several rolls, in which there is a pair of retaining rolls 41, 42, a pair of intermediate rolls 43, 44 an additional lower roll 45 in surface contact with the roll 44 for enhancing the grip of the rolls on the passing slivers, a set of delivery rolls 46, 47 and a set of crush rolls 48, 49. In this alternative arrangement, the lower crush roll 48 is also in surface contact with the upper delivery roll 47, but only for enhancing the grip of the rolls on the sliver or web, the roll 46 exerting the attenuating force upon the sliver or web.

Both in the embodiment of FIG. 1 and in the embodiment of FIG. 2 it has been found necessary for good results that the lower crush roll 7 respectively 48 has surface contact with the upper delivery roll 11 resp. 47 and thus forms part of the drafting apparatus itself. In the embodiment of FIG. 1, the lower crush roll 7 takes an active part in the attenuation of the slivers or web, whereas in the embodiment of FIGURE 2, the lower crush roll 48 enhances the grip of the upper delivery roll 47 upon the web.

Although the seed removing device as described above operates quite well at moderate speeds of the draw frame, the dust particles resulting from the pulverizing of the seeds, leaves and other impurities cause difficulties at the extremely high speeds of about 800 feet per minute of which modern draw frames are capable, since not all of the dust particles drop out of the web, but much of them accumulate on the crush rolls because of the oil and wax contained in the very small seeds which form part of the impurities. Upon crushing those seeds, the oil and wax form a thin sticky layer on the crush rolls which not only holds the seed particles, but also dry leaf particles and small fibres. This causes roll lapping in that the web leaving the drafting apparatus winds about the crush rolls.

Thus, a draw frame operating at high speed is according to a further feature of the invention, provided with scraper blades or doctor blades 59 on the upper crush roll and 51 on the lower crush roll. But in itself, the

scraper blades

50, 51 do not present a solution of the problem, since the dirt scraped away by the doctor blades accumulates in front of the blades in a very short time and ultimately drops back upon the delivered web, so that the impurities mix with the cotton fibres again. Accordingly, the draw frame is provided further with means for removing and discharging the dust particles obtained by the crushing action of the crush rolls upon the seed, leaves and other impurities in the cotton.

The upper doctor blade 50 is held against a mounting block 52 by means of a bar 53, a plurality of screws 54 holding the bar 53, the blade 5!) and the block 52 together. The blade 50 is narrower than the operating portion of increased diameter of the crush roll 12 and preferably its width corresponds as accurately as possible to the width of the web leaving the rolls 7 and 12. As stated above, the portion of the crush rolls 7 and 12 which is in contact with the cotton web, is covered with a thin layer of oil and wax which causes a lubricating action between the blade 50 and the roll 12, so that wear of the blade 5%) is prevented. But since the operating portion of the rolls 12 and 7 is wider than the web width, the outer portions of the rolls are not covered by Wax and if the blade 50 is wider than the web, the outer portions of the blade will wear away at a fast rate because of their contact with a dry roll part. Protruding from either end of the block 52 is a shaft 55 which is fixed against rotation in the center of the block 52 but further extends freely to both ends of the block 52 through a suitable bore of the block. The protruding ends of the shaft 55 are journalled in a lug 56 protruding from the upper end of a bush 57 which is fixed against rotation on the bearing 13 on the end of the roll 12. As described above, the bearing 13 is held against rotation in a recess 15 of the inclined front part of the frame member 4, by a pin 19 of the loading arm 14, which pin is itself loaded by a pressure spring 18 contained in an extension 17 of the arm 14, so that the pin 19 also provides the pressure which presses the roll 12 onto the roll 7. Although FIG. 3 only shows the bushing 57 at the right end of the roll 12, it will be apparent that a similar bushing 57 is also provided at the left end of the roll 12. The bushing 57 may be held rigidly on the bearing 13 by a set screw 58. Each end of the shaft carries an adjusting knob 59 which has a knurled circumference and which has a lateral set of lock teeth 60 which engage with similar lock teeth 61 on the outer end of the lug 56. The knob 59 is movable to a limited extent against spring pressure in axial direction, but it is not rotatable with respect to the shaft 55. Thus, by rotating the knob 59 so far that the lock teeth 60, 61 disengage and reengage one tooth further, the shaft 55 is torsioned with respect to its central mounting and this torsion causes a pressure of the blade 50 on the roll 12. In actual operations, it has been found that the pressure of the blade 50 on the roll 12 should be adjusted within the range of 2 to 4.5 pounds, such that the pressure of the blade 50 on the roll 12 is just sufficient to prevent lifting of the blade by the accumulating dust. By rotating the knob 59 in either direction, one should adjust the pressure of the blade 50 (within the range of 2 to 4.5 pounds) until the most satisfactory operation of the blade is obtained.

The mounting of the lower blade 51 for scraping the roll 7 is similar to the mounting of the blade 50 as to the mounting block 62 and bar 63 which hold the blade 51 and as to the shaft 64. But the teeth of the adjusting knob 65 on the shaft 64 face outwards and the shaft 64 is journalled in a bracket 66 which is fixed against the frame member 4 and which carries teeth 68 facing inwards to engage the teeth of the knob 65.

The position of the brackets 66 with respect to the frame members 4 and also the position of the bushing 57 with respect to the bearings 13 of the roll 12 are so selected that the lines of contact of the

doctor blades

50 and 51 with their respective rolls 12 and 7 are spaced from the nip of the rolls 12 and 7 in the direction of rotation of said rolls at an angle of about for the blade 51 and about for the blade 50 with respect to the center of the associated roll. Further, the

blades

50 and 51 are positioned at a small angle of divergence with respect to the tangent to the roll 12 resp. 7 at the line of contact with the blade, said angle being preferably about 20. The position of the

blades

50 and 51 is critical for obtaining a good operation, it being of course understood that a certain latitude of the adjustment is permitted so as to take account of the prevailing conditions of operation.

As stated above, an air flow is caused from the slot 35 at the front of the enclosure of the drafting apparatus toward the exhaust passages 32 at the bottom and 33 at the top of the drafting apparatus. The air flow from the slot 35 toward the conduit 33 passes the blade 50 while the air flow from the slot 35 towards the tunnel 32 passes the blade 51. The air flows should be very accurately guided by selection of the location and direction of the entrance and exhaust apertures and provision of further guide plates, if needed, since in the high speed draw frames in question, it is essential for the removal of the dust particles from the

blades

50 and 51 that air currents are generated which pass close to and transverse to the line of contact between each blade and its associated crush roll and substantially parallel to the plane of the blade. In FIG. 1, the cover 1 of the enclosure contains a guide plate 67 which extends horizontally over the upper crush roll 12 and its associated doctor blade 50 so that the airflow from the slot 35 towards the exhaust tunnel 33 is forced over the blade 50 towards the exhaust entrance provided between the rear end of the plate 67 and the lower face of the cover 1 and connected with the exhaust tunnel 33. As to the lower blade 51, the spacing between its mounting block 62 and the bottom 2 of the enclosure of the drafting apparatus should be selected so as to guide the air flow such that only a small portion of the total volume of air will pass directly from the slot 35 to the exhaust tunnel 32 and a larger amount of the air will follow a curved path upward, at both sides past the trumpet 28 and downward again, part of it passing close to the blade 51 for removing the dust.

It will be apparent that the position of the

blades

50 and 51 and the lay-out of the guide means for the air fiow in the enclosure have a direct interrelation and should be so selected that the desired air streams across the line of contact of the blade 50 with their respective rolls are obtained. The front side of the blades with their mountings, that is the side towards the air streams, should be kept as smooth as possible. By the cooperation of the features set forth, the air fiow in the enclosure will carry along any dust which accumulates on the

scraper blades

50, 51 and discharge it via the exhaust tunnels before the dust can build up to a substantial extent upon the

blades

50 and 51. Since the air currents should be capable of carrying away the dust from the scraper blades, the air speed should be relatively high so that a relatively high suction should be used.

It will be noted that the embodiments described are only examples and that modifications are possible within the scope of the invention.

The means for mounting the scraper blades may differ from the embodiment shown, e.g. there may be provided a spiral spring or a helical spring for loading the shafts 55 or 64 instead of using those shafts themselves as torsion bar springs. Also, magnetic attraction may be used to hold the rolls 7 and 12 together or to hold the

blades

50 and 51 on the rolls 7 and 12.

The seed and crush removing device may be used in a single draw frame in the sequence of operation by which the raw cotton is spun into a yarn, but since it is customary to use at least two successive draw frames in the sequence of the spinning process, it is preferred to install the seed removing device on both draw frames of the sequence of operations, so that any impurities which have not been removed in the first draw frame,will be removed in the second draw frame. Even in mills which have already crush rolls on their carding engines, it will be advantageous to mount the present device on at least one draw frame subsequent to the carding engine so as to remove any impurities remaining in the cotton. It should be noted, however, that the pair of crush rolls should not merely be installed as a separate unit behind the drafting apparatus of a high speed cotton draw frame, but it should be incorporated into the drafting apparatus so that one of the crush rolls has surface contact with one of the delivery rolls of the drafting apparatus.

The invention does not impose limitations on the general construction of the draw frame and all conventional parts thereof may be of usual construction, it being only necessary to observe the conditions set forth for the mounting of the crush roll pair and for the cleaning means therefore. For instance, the spring loading of the several upper draft rolls and also of the upper crush rolls may be replaced by a Weight loading. Instead of journalling the rolls in bearings such as 13, the central or operating portion of the draft rolls and of the crush rolls may be mounted via anti-friction bearings on a stationary shaft which extends through the hollow rolls and which is held in a fixed angular position. Thus, there is less danger of accidental small changes e.g. in the angular position of the doctor blade 50. Instead of the rubbers 31, other means for clearing the rolls may be used. The air flow around the crush roll system may be provided by blowing air into the enclosure instead of exhausting air from the enclosure as described.

These and other modifications will be apparent to those skilled in the art and it is intended to cover all changes and modifications of the preferred embodiments of the invention herein chosen 59! the purposes of the disclosure 8 which do not constitute departures from the spirit and scope of the invention.

What I claim is:

1. High speed cotton draw frame comprising drafting means including a series of groups of interengaging upper and lower draft rolls and a pair of interengaging smooth metal surfaced crush rolls so as to constitute successive nips, means for rotating the rolls for forwarding a plurality of carded cotton slivers through said nips from the entrance end to the delivery end of the drafting apparatus, successive groups of upper and lower draft rolls running at increased circumferential speeds relative to the preceding group of rolls so as to attenuate the slivers and form them into a web, the pair of crush rolls being situated at the delivery end of the drafting means and receiving the web, pressure means for causing pressure between the rolls of each group of draft rolls and between the pair of crush rolls, the pressure between the pair of crush rolls being selected to crush and disintegrate seeds, leaves and other impurities entrained in the web passing through the nip of the crush rolls, the lower crush roll being in surface contact with the last draft roll in the sequence of groups of draft rolls and pressure means causing pressure between the lower crush roll and said last draft roll.

2. High speed cotton draw frame as claimed in claim 1, comprising a first driven lower draft roll, a first upper draft roll in surface contact with said first lower draft roll so as to advance a plurality of slivers forwarded into the nip of said first lower and upper draft rolls, a second lower draft roll driven at a higher circumferential speed than said first lower draft roll, two upper draft rolls in surface contact with spaced areas of said second lower draft roll so as to grip and attenuate the slivers leaving said first lower and upper draft rolls and to further forward said slivers, a lower crush roll driven at a higher circumferential speed than said second lower draft roll, a last upper draft roll in surface contact with said lower crush roll, an upper crush roll in surface contact with a further area of said lower crush roll, the lower crush roll in combination with the last upper draft roll and the upper crush roll gripping and attenuating the spread out cotton slivers leaving the group of said second lower crush roll and the two intermediate upper draft rolls.

3. High speed cotton draw frame as claimed in claim 1, comprising a first driven lower draft roll, a first upper draft roll in surface contact with said first lower draft roll for advancing a plurality of slivers forwarded into the nip of said first lower and upper draft rolls, a second lower draft roll driven at a higher circumferential speed than said first lower draft roll, a third lower draft roll driven at an identical speed as the second lower draft roll, a second upper draft roll in surface contact with both said second and said third lower draft rolls for gripping and attenuating the slivers leaving the nip of said first upper and lower draft rolls, a fourth lower draft roll driven at a higher circumferential speed than said second and third lower draft rolls, a lower crush roll driven at an identical circumferential speed as said fourth lower draft roll, a third upper draft roll in surface contact with both said fourth lower draft roll and said lower crush roll for gripping and attenuating the spread out slivers leaving the group of said second and third lower draft rolls and said second upper draft roll, and an upper crush roll in surface contact with said lower crush roll..

4. High speed cotton draw frame as claimed in claim 1, in which the diameter of the portions of the crush rolls which engage the fibrous web is a larger diameter than the portions of the draft rolls operating on the processed slivers.

5. High speed cotton draw frame as claimed in claim 1, in which the pressure between the upper and lower crush roll is to pounds at each end.

6.-High speed cotton draw frame comprising drafting mechanism including a series of groups of interengaging upper and lower draft rolls and a pair of interengaging smooth metal surfaced crush rolls so as to constitute successive nips, means for rotating the rolls for forwarding a plurality of carded cotton slivers through said nips from the entrance end to the delivery end of the drafting mechanism, successive groups of upper and lower draft rolls running at increased circumferential speeds relative to the preceding group of rolls so as to attenuate the slivers and form them into a web, the pair of crush rolls being situated at the delivery end of the drafting apparatus and receiving the web, pressure means for causing pressure between the rolls of each group of draft rolls and between the pair of crush rolls, the pressure between the pair of crush rolls being selected to crush and disintegrate seeds, leaves and other impurities entrained in the web passing through the nip of the crush rolls, trumpet means for condensing the web leaving the crush rolls into a sliver, a doctor blade on each of said crush rolls spaced from their nip in the direction of rotation of said rolls and positioned at a small divergence angle from the tangent to the associated crush roll away from the nip of the pair of crush rolls, means for supporting each doctor blade so that it may rock about an axis parallel to and spaced from the associated crush roll, means for resiliently urging the end of each doctor blade against its associated crush roll, means for adjusting the resilient pressure of each doctor blade on its associated crush roll, an enclosure for the drafting mechanism inclusive of the crush rolls with doctor blades and the trumpet means for receiving the sliver, an air inlet to and an air outlet from the enclosed space of the enclosure, means for generating air flow through the enclosed space and means for guiding said air flow so that air streams adjacent and transverse to the line of contact between each doctor blade and its associated crush roll and substantially parallel to the plane of the doctor blade are provided, whereby disintegrate-d impurities accumulated on the doctor blades are carried along by the air streams to the air outlet.

7. High speed cotton draw frame as claimed in claim 6, having means for guiding the air flow so as to generate two separate air streams diverging from each other at the delivery end of the nip of the pair of crush rolls and further flowing each transverse to the line of contact between the upper and the lower doctor blade respectively and its associated crush roll.

it. High speed cotton draw frame as claimed in claim l0 6, in which the angle of divergence of the doctor blades with respect to the tangent to the associated crush roll is about 20.

9. High speed cotton draw frame as claimed in claim *6, in which the line of contact of the upper doc-tor blade is spaced at an angle of about 180 from the nip between the upper and lower cnish rolls and the line of contact of the lower doctor blade is spaced at an angle of about from the nip of the upper and lower crush rolls.

10. Drafting mechanism for a high speed cotton draw frame, including a series of groups of interengaging upper and lower draft rolls and a pair of interengaging smooth metal surfaced crush rolls so as to constitute successive nips, means for rotating the rolls for forwarding a plurality of carded cotton slivers through said nips from the entrance end to the delivery end of the drafting apparatus, successive groups of upper and lower draft rolls running at increased circumferential speeds relative to the preceding group of rolls so as to attenuate the slivers and form them into a !web, the pair of crush rolls being situated at the delivery end of the drafting mechanism and receiving the web, pressure means for causing pressure between the rolls of each group of draft rolls and between the pair of crush rolls, the pressure between the pair of crush rolls being selected to crush and disintegrate seeds, leaves and other impurities entrained in the web passing through the nip of the crush rolls, the lower crush roll being in surface contact with the last draft roll in the sequence of groups of draft rolls and pressure means causing pressure between the lower crush roll and said last draft roll.

References Cited by the Examiner UNITED STATES PATENTS 2,509,148 5/ 1950 Hurst 1966 X 3,020,600 2/1962 West 19-263 X 3,101,504 8/1963 Gasser 19-263 X FOREIGN PATENTS 1,327,503 4/ 1963 France.

947,121 1/1964 Great Britain.

MERVIN STEIN, Primary Examiner. L: K R.Il D1Zv rti ar Er i n

Claims

1. HIGH SPEED COTTON DRAW FRAME COMPRISING DRAFTING MEANS INCLUDING A SERIES OF GROUPS OF INTERENGAGING UPPER AND LOWER DRAFT ROLLS AND A PAIR OF INTERENGAGING SMOOTH METAL SURFACED CRUSH ROLLS SO AS TO CONSTITUTE SUCCESSIVE NIPS, MEANS FOR ROTATING THE ROLLS FOR FORWARDING A PLURALITY OF CARDED COTTON SILVERS THROUGH SAID NIPS FROM THE ENTRANCE END TO THE DELIVERY END OF THE DRAFTING APPARATUS, SUCCESSIVE GROUPS OF UPPER AND LOWER DRAFT ROLLS RUNNING AT INCREASED CIRCUMFERENTIAL SPEEDS RELATIVE TO THE PRECEDING GROUP OF ROLLS SO AS TO ATTENUATE THE SILVERS AND FORM THEM INTO A WEB, THE PAIR OF CRUSH ROLLS BEING SITUATED AT THE DELIVERY END OF THE DRAFTING MEANS AND RECEIVING THE WEB, PRESSURE MEANS FOR CAUSING PRESSURE BETWEEN THE ROLLS OF EACH GROUP OF DRAFT ROLLS AND BETWEEN THE PAIR OF CRUSH ROLLS, THE PRESSURE BETWEEN THE PAIR OF CRUSH ROLLS BEING SELECTED TO CRUSH AND DISINTEGRATE SEEDS, LEAVES AND OTHER IMPURITIES ENTRAINED IN THE WEB PASSING THROUGH THE NIP OF THE CRUSH ROLLS, THE LOWER CRUSH ROLL BEING IN SURFACE CONTACT WITH THE LAST DRAFT ROLL IN THE SEQUENCE OF GROUPS OF DRAFT ROLLS AND PRESSURE MEANS CAUSING PRESSURE BETWEEN THE LOWER CRUSH ROLL AND SAID LAST DRAF ROLL.