US2698970A

US2698970A - Tow crimper

Info

Publication number: US2698970A
Application number: US258079A
Authority: US
Inventors: Dan B Wicker
Original assignee: American Cyanamid Co
Current assignee: Wyeth Holdings LLC
Priority date: 1951-11-24
Filing date: 1951-11-24
Publication date: 1955-01-11
Anticipated expiration: 1972-01-11

Description

Jan. 11, 1955 Filed Nov. 24, 1951 D. B. WICKER TOW CRIMPER 5 Sheets-SheerI l ZwfM ATTO R N EY Jan. 11, 1955 D. '8. wlcKER 2,698,970

TOW CRIMPER Filed Nov. 24, 1951 3 Sheets-SheeiI 2 lNvENToR 7M XM ATTORNEY Jan. 1l, 1955 D. B. wlcKER Tow CRIMPER Filed Nov. 24, 1951 3 Sheets-Sheet 3 NNNNNN O R BY if i ATTORNEY fibers.

United States PatentO TOW CRIMPER Dan B. Wicker. Stamford, Conn., assignor to American Cyanamid Company, New York, N. Y., a corporation of Maine Application November 24, 1951, Serial No. 258,079

7 Claims. (Cl. 19-66) This invention relates to apparatus for crimping or crlnkling tow or bundles of textile fibers, especially parallel continuous artificial fibers.

In the processes for producing spun yarn from staple fibers, it is desirable to use crimped fibers, that is fibers which are crinkled or curled, in order to obtain superior yarns. and therefore should be crimped or crinkled by artificial means as a prerequisite to spinning the best yarn there- Ifrom. The crimping step is preferably carried out prior to cutting continuous extruded fibers to staple lengths.

respective of the distance between feed rolls.

Still another object of the invention is to provide an improved crlmplng device in which the edges of certain Extruded bers in general do not have this curlV With a crimper of the nip roll and stufiing box type,

crimping chamber walls are automatically maintained at a constant clearance from the surface of the nearer -feed roll regardless of the spacing between the feed rolls.

Other objects and advantages of the invention will be apparent to those skilled in the art from the detailed description hereinbelow.

The present invention is concerned with a tow crimping device and especially with the structural relation between the feed rolls and the associated crimping chamber. In particular it relates to a structural arrangement for 4maintaining each of the leading edges of the crimping chamber in fixed relation to one of the feed rolls even when the rolls move toward or away from one another.

The greatest utility of the apparatus appears to lie in crimping artificial continuous filament fibers; however, it

can also crinkle natural fibers and discontinuous filament Hence, even though the device disclosed herein is particularly adapted for the crimping of polyacrylonitrile fibers of the types disclosed in Patent No. 2,558,730

to Cresswell, it may be employed with any textile fibers such as viscose and cuprammonium rayon, cellulose acevtate and other cellulose derivatives, nylon, wool, cotton,

silk, etc.

The present invention is best understood by reference to the accompanying drawings illustrating the invention in which:

Fig. l is a sectional elevation of the tow crimper;

Fig. 2 is a fragmentary sectional view of Fig. l with certain elements removed;

Fig. 3 is a sectional view taken on line 3-3 of Fig. 2,

and

Fig. 4'is a fragmentary sectional elevation taken on the center line of a modified form of the invention.

Referring now to Fig. l, frame 10 carries fixed bearings (not shown) for the shaft 12 to which is keyed feed roll 14. Another set of fixed bearings (not shown) mounted on frame 10 rotatably supports the shaft 16 on which is pivotally mounted a bracket 1S equipped with a pair of bearings (not shown) supporting the rotating 4shaft 20 onV which is keyed the feed roll 22 of ,similar construction to roll 14. Both rolls are positively driven lthe fiber bundle passing between the rolls.

y 2,698,970 Patented Jan. 11, 1955 in synchronization. The width of the peripheral surfaces of these rolls is usually quite narrow 1n comparison with their diameters, and a milled or fluted surface is recommended to insure a positive feed through the rolls, especially if damp fibers are being crimped. Such indentations desirably have rounded edges to avoid any possibility of injury to the fibers. The minimum clearance between the coacting rolls may be regulated by means of the adjusting screw 24, and the compression spring 26 is provided to exert pressure on the bracket 18 and thus on the tow in the nip of the rolls. This spring permits movement of roll 22 up or down in response to the thickness of The pressure exerted by spring 26 may be varied as desired by means of the adjusting screw 28 provided with conventional locking means. At each end of roll 22 a support member 30 is pivotally mounted on shaft 20 in bearings 31 (see Fig. 3) so that it may be turned clockwise or counterclockwise independently of the rotation of shaft 20. On the lower shaft 12 the link members 32 are mounted in the same manner, that is they are provided with bearings 33 (Fig. 3) which permit them to pivot freely on shaft 12.

Turning now to Figs. 2 and 3, it will be seen that the link plates 32 are pivotally joined to the supports 30 by means of the pins 34. The dowels or spacer bolts 36 are provided to insure the correct spacing of the plates 32 and a similar bolt 38 is used for the same purpose in respect to the support members 30.

- As is readily apparent in Figs. 2 and 3 the plates or walls 40 are rigidly attached to the supports 30 and are spaced at the correct distance by means of the spacer 42 through which passes bolt 44. Spacer 42 should be of a size sufficient to provide a running fit, say about 0.001 inch clearance, between the side wall members 40 and the ends of

rolls

14 and 22. In order to prevent the galling or scoring of the wall plates 40 and the disc-like rolls, it has been found desirable to construct the wall members entirely of solid nylon or with liners of nylon. Micarta and other materials of suitable bearing properties and relatively good dimensional stability may be used in place of the nylon.

The top and bottom of the crimping chamber are bounded by the upper and lower walls or

guide shoes

46 and 48 respectively and the rear of the crimping chamber is yieldably closed by the pivoted gate 50 which is loaded as desired withthe weights 52. The

shoes

46 and 48 are provided with the

edges

54 and 56 respectively which are closely adjacent to the surfaces of the rolls. The purpose of the close fit between the crimping box and the roll peripheries is to assure that all fibers enter this boxwithout fouling the machine as they are pushed forward by the rolls. Although a knife edge may be employed for the purpose, a sharpened or honed edge is not necessary as no cutting is reduired. The location of these edges with respect to the peripheries of the rolls is important and the best results have been obtained by maintaining a clearance between the edges and the associated rolls substantially less than the average diameter of the fibers being processed: for instance 0.001 clearance for filaments of about 0.002 average diameter. Larger clearances running up to about 5 to l0 times the average diameter of the filaments have been fairly satisfactory, but this required closer attention by the machine operators in removing stray and abraded fibers which followed the rolls instead of entering the crimping chamber. However, operations with a still larger clearance amounting to about l5 diameters were unsuccessful as the tow either 'jammed against the

edges

54 and 56 or escaped outside separated from the center of shaft 20 by a distance very slightly greater than the radius of roll 22. As the upper kroll v22 moves toward and away from roll 14 1n response to variations in the thickness of the tow,

shoes

46 and 48 move away from or toward the nipv of the rolls; but the edge 54 is always maintained at a constant clearance from the roll 22, since the support members 30 swing on thev shaft carrying roll 22. A similar clearance is maintained between roll 14 and. edge 56 by locating the edge 56 on the center line of the pivots 34. This, of' course, fixes the distance between the edge 56 and the center of shaft 12, and therefore, itv fixes' the clearancel or distance between the edge and the surface of roll 14. Thus edge 56 is maintained at a fixed distance from roll 14 regardless of the angular positions of the supportsv 30 and links 32 even` though the edge is fixedly mounted on supports 30 which are pivoted on shaftv 20 rather than on the shaft supporting roll 14. In order to restrict the movement of

edges

54 and 56 into the nip` of the rolls and consequently to similarly limit the maximum separation of the rolls, an adjustable stop screw S equipped with a lock nut is provided (see Fig. l). This screw restricts the swing. of the link. plates 32. It willy also be noted that the

Wall members

46 and 48 are arcuately shaped on the side facing the roll' associated therewith in order to maintain sutiicient. clearance at all points;

Fig. 4 illustrates. a modified form of the invention as well as its operation. A textile lubricant, such as triethylene glycol or emulsifiable petroleunr oil, is allowed to ow from a reservoir 60 through line 62 controlled by stop cock 64 andl to drip onto roll 22. Other feed means such as metering pumps' may be used if desired. It appears that less physical damage to the fibers from abrasion during thev crimping operation occurs when such an agent isl used. In processing polyacrylonitrile fibers in the wet stretched (oriented) gel state, triethylene glycol and glycerine are preferred over conventional textile lubricants since they also act as humectants or humidifying agents which aid subsequent processing. of the crimped fiber. In the modification shown in Fig. 4,. the

shoes

146 and 148 are' of a slightly different form and. the springloaded gate 150 is mounted. for movement in a straight line instead of swinging on a hinge. This reciprocating outlet gate is attached to a shaft 66y mounted to slide freely in the guides 68 and 7'0 which are' fastened to bracket 72 mounted on supports 30. If desired suitable guide means may be providedl for preventing rotation of the gate, as for instance, by employing a shaft 66 of square cross-section sliding in square holes in

guide members

68 and 70. The pressure exerted by the gate isl determined by the strength of spring 74 and by the degree to which it is compressed. TheA spring compression may be easily adjusted by shifting guide 70, whichy is adjustably mounted (not shown) in conventionalv manner on bracket 72, either nearer to or farther from the discharge endl of the crimping chamber. Where only a small back pressure is desired as in the case of. fibers in the wet gel state, a reciprocating gate actuated by a small force, e. g.4 5 ounces, is preferred. With dry, firm, unyielding fibers the pivotal galte of Fig. 1 and heavier loading produce excellent resu ts.

In operating the tow erimper described. herein, one or more bundles or ropes of parallel. continuous fibersA are fed into the nip of the feed rolls 14 and 22v which cornpress the material into a ribbon and drive it into the crimping chamber. The movement of this ribbon into the chamber is resisted by the

gate

50 or 150 pressing against the material already in they chamber and the pressure crimpsf the ribbon into fine crinkles or curls and also wads it into folds of a length corresponding to the height of the chamber; The force exerted by the rolls is, of course, greater than the back pressure of the gate; so the gate is pushed open. and the folded, crimped ribbon is discharged downward. During operation of the machine,

gate

50 or 150 usually moves back and forth somewhat but not into the fully closed. position. From' this it should not be thought that the gate is unnecessary, for in its absence the rolls simply feed the tow through the crimping chamberA as a liat uncrimped ribbon; therefore, even the rather slight pressures exerted by the gate are essential to the crinkling or crimping of the fibers.

The degree of crimping is governed chiey by the amount of back pressure imposed by the` gate on the ribbon of tow in the' crimping chamber. Increasing the pressure produces a hner crinkling of the fibers and a decrease in the force exerted by the gate results in a coarser crimp. Actual trial is necessary to determine the optimum pressure for each type of fiber, as the required force. seems to vary with the kind, condition and probably size of the individual filaments'.

While it is recommended that both rolls be positively driven at the same speed, this invention also contemplates operations in which only one roll is positively driven as well as those in which both rolls are driven at different speeds. The drive mechanism for separable rolls is well understood by those skilled in the art therefore is not described here. In general peripheral linear roll speeds of about 20 to about 110 yards per minute are contemplated and excellent results have been obtained with polyacrylonitrile tow at 65 yards per minute; however, the speed does not appear to be critical and may be higher or lower than the values indicated.

Although the invention has been described in connection with a lower roll 14 mounted in fixed bearings and a movable spring-loaded upper roll 22, the invention is not limited to this particular structure since the upper roll might be the fixed onel and the lower one springloaded orv both rolls may be mounted in movable or displaceable bearings. Thus supporty plates 30 may be swingably mounted on a shaft mounted in fixed bearings and link plates 32 similarly mounted on a shaft or axle mounted in movable bearings'.

Some crimping devices in the prior art have been limited by reason of their structure to operating in only one position, for example, the downward feeding of. tow between horizontally disposed rolls. This is not true of the device described herein as it may be operatedV in any position at any angle although slight and obvious modification of the crimping chamber outlet gate and its loading means may be necessary. The vertical alignment of the rolls as shown in the drawings is advantageous in that the nip of the rolls squeezes any excess lubricating or humidfying agent off of the tow instead of allowing it to drain into and over the crimping chamber to rewet the crimped product.

While there are disclosed above only a limited number of embodiments of the structure of the invention herein presented, it is possible to produce still other embodiments without departing from the inventive concept herein disclosed, and it is desired therefore that only such limitations be imposed on the appended claims as are stated therein, or required by the prior art.

Having described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A device which comprises parallel coacting first and second feed rolls, a chamber having an open side facing the bite of the rolls, an outlet gate at another side of the chamber operable at a preselected pressure, a support pivotally mounted on the shaft. of the tirst roll, a first wall of the chamber fastened to the support and provided with a first edge substantially parallel to the bite of the rolls and closely adjacent to the periphery of the first. roll, a link pivotally attached to both the support and the shaft of the second roll, a second wall of the chamber opposite the first wall and provided with a second edge substantially parallel to the bite ofthe rolls and closely adjacent to the periphery of the second roll, the second wall being fastened to the support with the second edge substantially aligned with thel center line ofv the pivot connecting the support and link, whereby said edges are maintained at a constant distance from the axes of the respective rolls regardless of the distance between the peripheral surfaces of the rolls.

2. A device for crimping a bundle of substantially parallel continuous fibers which comprises positively driven parallel coacting first and second feed rolls for feeding the fiber bundle into a crimping chamber, the crimping chamber having an open side facing the bite of the rolls, an outlet gate at another side of the chamber operable at a preselected pressure toI releasey the bundle of crimped fibers from the chamber, a support pivotally mounted on the shaft of the first roll,,a first wall ofthe chamber fastened to the support and provided with a first edge substantially parallel to the bite of the rolls and closely adjacent to thev periphery of the first roll, a link pivotally attached to both the support and the shaft of the second roll, a second. wall of the chamber opposite the iirst wall and provided with a second edge substantially parallel to the bite of the rolls and closely adjacent to the periphery of the second roll, the second wall being fastened to the support with the second edge substantially' aligned with the center line of thel pivot connecting the support and link, whereby said. edges are maintained at a constant distance from the peripheries of the respective rolls regardless of the distance between the peripheral surfaces of the rolls.

3. A device for crimping a bundle of substantially parallel continuous fibers which comprises parallel coacting first and second feed rolls, a crimping chamber having an open side facing the bite of the rolls, an outlet gate at another side of the chamber operable at a preselected pressure to release the bundle of crimped fibers from the chamber, a movable mounting for one of the rolls for varying the distance between the rolls in response to the thickness of the fiber bundle, means for regulating the pressure of the rolls on the fiber bundle, a support pivotally mounted on the shaft of the first roll, a first wall of the chamber fastened to the support and provided with a first edge substantially parallel to the bite of the rolls and closely adjacent to the periphery of the first roll, a

link pivotally attached to both the support and the shaft of the second roll, a second wall of the chamber opposite the first wall and provided with a second edge substantially parallel to the bite of the rolls and closely adjacent to the periphery of the second roll, the second wall being fastened to the support with the second edge substantially aligned with the center line of the pivot connecting the support and link, whereby said edges are maintained at a constant distance from the axes of the respective rolls regardless of the distance between the peripheral surfaces of the rolls.

4. A device for crimping a bundle of substantially parallel continuous fibers which comprises parallel coacting first and second feed rolls, means for applying a fiber lubricant to the fiber bundle on the rolls, a crimping chamber having an open side facing the bite of the rolls, an outlet gate at another side of the chamber operable at a preselected pressure to release the bundle of fibers from the chamber, a support pivotally mounted on the shaft of the first roll, a first wall of the chamber fastened to the support and provided with a first edge substantially parallel to the bite of the rolls and closely adjacent to the periphery of the first roll, a link pivotally attached to both the support and the shaft of the second roll, a second of the pivot connecting the support and link, whereby v. preselected pressure to release the bundle of crimped wall of the chamber opposite the first Wall and provided with a second edge substantially parallel to the bite of the rolls and closely adjacent to the periphery of the second roll, the second wall being fastened to the support with the second edge substantially aligned with the center line of the pivot connecting the support and link, whereby said edges are maintained at a constant distance from the axes of the respective rolls regardless of the distance between the peripheral surfaces of the rolls.

5. A device for crimping a bundle of substantially parallel continuous fibers which comprises parallel coacting first and second feed rolls, a crimping chamber having an open side facing the bite of the rolls, a reciprocable outlet gate at another side of the chamber for releasing the bundle of crimped fibers from the chamber, means for applying a preselected pressure against the opening of the gate, a support pivotally mounted on the shaft of the first roll, a first wall of the chamber fastened to the support and provided with a first edge substantially parallel to the bite of the rolls and closely adjacent to the periphery of the first roll, a link pivotally attached to both the support and the shaft of the second roll, a second wall of the chamber opposite the first wall and provided with a second edge substantially parallel to the bite of the rolls and closely adjacent to the periphery of the second roll, the second wall being fastened to the support with the second edge substantially aligned with the center line fibers from the chamber, a movable mounting for one of the rolls for varying the distance between the rolls in response to the thickness of the fiber bundle, means for regulating the pressure of the rolls on the fiber bundle, means for applying a fiber lubricant to the fiber bundle on the rolls, a support at each end of the first roll pivoted on the shaft thereof, a link at each end of the second roll attached pivotally both to the shaft thereof and to the corresponding support, a first wall of the chamber fixed to both supports and provided with a first edge adjacent and parallel to the bite of the rolls and closely adjacent to the peripheral surface of the first roll, a second wall of the chamber fixed to both supports and provided with a second edge substantially aligned with the center line of the pivots connecting the supports to the links, the second edge being adjacent and substantially parallel to the bite of the rolls and closely adjacent to the peripheral surface of the second roll, and additional walls of the chamber on to the supports adjoining the first and second Walls and further enclosing the bite of the rolls, the width of the first and second walls being very slightly greater than the width of the peripheral surfaces of the rolls to space the additional wall members sufciently to provide a running fit between the additional wall members and the ends of the rolls, whereby the clearances between each edge and the peripheral surface of the associated roll remain constant and independent of the distance between the peripheries of the rolls.

7. A device which comprises parallel coacting first and second feed rolls, a chamber having an open side facing the bite of the rolls, an outlet gate at another side of the chamber operable at a preselected pressure, a support pivotally mounted on the shaft of the first roll, a first wall'of the chamber fastened to the support and provided with a first edge closely adjacent to the periphery of the first roll, a link pivotally attached to both the support and the shaft of the second roll, a second wall of the chamber opposite the first wall and provided with a second edge closely adjacent to the periphery of the second roll, the second wall being fastened to the support with the second edge substantially aligned with the center line of the pivot connecting the support and link, whereby said edges are maintained at a constant distance from the axes of the respective rolls regardless of the distance between the peripheral surfaces of the rolls.

References Cited in the file of this patent UNITED STATES PATENTS 2,090,669 Dreyfus Aug. 24, 1937 2,156,723 Esselmann May 2, 1939 2,311,174 Hitt Feb. 16, 1943 2,438,469 Wilkie Mar. 23, 1948 2,575,837 Rainard Nov. 20, 1951 FOREIGN PATENTS 487,711 Great Britain June 24, 1938