US3393880A

US3393880A - Strand control apparatus

Info

Publication number: US3393880A
Application number: US537526A
Authority: US
Inventors: John V Keith; Hans H Richter
Original assignee: Leesona Corp
Current assignee: Leesona Corp
Priority date: 1966-03-25
Filing date: 1966-03-25
Publication date: 1968-07-23
Anticipated expiration: 1985-07-23
Also published as: BE696097A; GB1181244A; NL6704334A; ES338417A1; GB1181245A; DE1710089A1; CH456289A

Description

y 1968 J. v. KEITH ETAL STRAND CONTROL APPARATUS 2 Sheets-Sheet 1 Filed March 25. 1966 FIG.6

SOURCE 'OF PRESSURIZED FLUID INVENTORS JOHN v. KEITH Y HANS H. RICHTER Mel/2 WW 4 Anew-5W iy 1968 J. v KEETH ETAL I 3,393,@

- Q STRAND CONTROL APPARATUS Filed Harch'25, 19 66 a Sheets-Sheet 2 INVENTORS JOHN V KEQTH HANS H. RECHTER ig Z5541! MO ATTORNEYS United States Patent 3,393,880 STRAND CONTROL APPARATUS John V. Keith, Warwick, and Hans H. Richter, Cranston, R.I., assignors to Leesona Corporation, Warwick, R.I., a corporation of Massachusetts Filed Mar. 25, 1966, Ser. No. 537,526 Claims. (Cl. 24245) ABSTRACT OF THE DISCLOSURE A guide for an advancing strand of yarn. The strand is guided on a cushion of air injected at a base of the guide and between guide fingers. Very low frictional resistance to movement of the strand and tension regulation of the strand are provided by the guide.

This invention relates generally to textile equipment and, more particularly, to a guide for a strand of yarn.

Throughout the present specification and claims, the term yarn is employed in a general sense to indicate any type of attenuated material, and the word package is intended to designate the wound mass of yarn, whatever its form or shape.

The invention is applicable to many phases of yarn handling the particular end uses disclosed herein being merely illustrative and not limiting thereof.

In order to provide uniform quality throughout a package of yarn, it is desirable that tension in the yarn be maintained at a substantially constant value, even as the speed of the winding yarn changes. Various methods have been employed to maintain a substantially constant tension in it as the yarn advances to the package being wound. Devices have also found widespread use which provide for progressively adjusting yarn tension as the package grows in size. However, prior attempts at accommodating rapid fluctuations in yarn tension as the yarn is traversed to and fro on the package have not been entirely satisfactory. r

Take-up machines often employ a pivotally mounted arm having a yarn guide to maintain the yarn at a constant tension or a progressively decreasing tension as disclosed in the commonly assigned patent to J. V. Keith, No. 3,048,343, issued Aug. 7, 1962.

In the machine disclosed in the cited patent, for example, the physical inertia of the pivotal arm is far too great to permit its oscillation at the rate or frequency necessary to accommodate the fluctuations in the effective yarn length as it traverses back and forth onto the package.

In the production of torque stretch yarns, thermoplastic yarn such as nylon or treated natural fibers are drawn from a supply source into a heater and then through a false twist spindle onto a suitable take-up roll or package. Twist imparted by the false twist spindle backs up or migrates through the yarn situated within the heater, and the heater functions to set this twist. Attempts have been made heretofore to provide for a plurality of yarn passes through a heater. This has usually been performed by reversal of the yarn passing one or more times over rotatable rods or rollers. However, so long as there is substantial frictional engagement of the yarn over a yarn guide, the guide will operate as a twist trap to impede passage thereover of the false twist.

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The invention, in brief, is directed to a guide over which yarn is advanced on a cushion of air and guided between a spaced apart pair of finger elements to provide very low friction relative to the yarn.

Accordingly, it is an object of the invention is to provide a new and improved guide for an advancing strand.

Another object of the invention is the provision of a new and improved guide to support an advancing strand of yarn on a cushion of air and effectively prevent damage to the yarn.

A further object of the invention is to provide a new and improved yarn guide which is substantially devoid of friction relative to the yarn.

Yet another object of the present invention is the provision of a new and improved guide which will maintain a desired tension value in an advancing strand. A related object is provision of such a guide in conjunction with regulating mechanism for maintaining substantially constant tension in the advancing strand. Another related object is provision of such a guide for compensating for fluctuations in tension in the strand.

Other and further objects will be apparent from the following description and the accompanying drawings, in which:

FIG. 1 is an exploded perspective view of a strand guide constructed in accordance with the invention;

FIG. 2 is a perspective view of a winding machine employing the invention;

FIG. 3 is a schematic front elevation view of the takeup roll illustrating the variation in length of a strand of yarn being traversed or fanned across the surface of the rotating package;

FIG. 4 is an enlarged fragmentary side elevation View of compensating arm of the machine of FIG. 2;

FIG. 5 is a fragmentary side elevation view of a preferred modification of the compensating arm illustrated in FIG. 4;

FIG. 6 is a front elevation view of the compensating arm of FIG. 5;

FIG. 7 is a front elevation view of a stretch yarn machine of the false twist type, illustrating a heater therefor in accordance with the invention; and

FIG. 8 is a sectional view taken along lines 88 of FIG. 7.

Referring now to the drawings, FIG. 1 illustrates the pneumatic yarn guide 10 in an exploded condition. The guide includes a pair of finger elements 12. A seal member 14 and a pair of pins 16 provides a base portion 17 of the guide. At least one and, if desired, both of the finger elements 12 is formed with a recess or chamber 18 formed at one end thereof. Clearance holes 20 are formed in each of the elements 12, passing through the side walls thereof into chambers 18. These clearance holes 20 receive a fastener 2 snugly therethrough which may be a bolt or the like. The fastener is provided with a hollow shank having an inlet 24 and orifices 26 (see FIG. 8) spaced around the circumference in communication with chamber 18. The seal 14 is of such a shape and size as will surround chamber 18 on three sides, but is open on the fourth side leading to the zone between extended fin er elements or portions 28. The fastener 22 serves to draw elements 12 together in side-by-side abutting relationship with the distensible seal 14 fixed therebetween. The outer end of fastener 22, i.e., the end opposite the head thereof, is desirably received through an apertured supporting member 29 such as illustrated in FIG. 8 and thereupon secured as by a nut 30 or other suitable closure member. As shown schematically in FIG. 8, the outer end of the hollow fastener 22 is connected to a source of pressurized fluid 32, such as pressurized air.

When the elements 12 are thus clamped together by means of

fasteners

22 and 30, it will be appreciated that a space or passage 34 will result between the finger elements 28 from the thickness of seal 14. Of course, the spacing between the extended portions 28 is variable depending upon the thickness and compressibility, if any, of the seal. The passage 34 provides a zone adapted to receive a strand of yarn Y therethrough and the tip ends of extended portions 28 art beveled or rounded for easy reception of the yarn therein.

The pins 16 are tightly held as by a press fit in notches 36 formed in each of the finger elements 12 at opposite ends of the base 17. The pins serve to maintain alignment of the cooperating elements 12. Additionally, since the pins are situated at the outlet of chamber 18 into passage 34, these pins provide guards which act to prevent contact of the yarn with the edges of seal 14, which contact might seriously abrade and perhaps even break the yarn. From what has just been described, it will be apparent that gaseous fluid of any suitable composition is directed under a predetermined pressure through hollow fastener 22. The fluid passes through orifices 26 into chamber 18 which thereby becomes, in effect, a plenum chamber, the fluid therein being at a higher pressure than ambient. The pressurized fluid will then issue from an inlet 38, in the form of an elongated slot which extends between opposite ends 39 of the base 17 and which connects passage 34 with chamber 18 by reason of the discontinuity of seal 14, and will be directed transversely of the path of the yarn. The yarn will thereby be caused to float upon the cushion of pressurized fluid. Although the yarn is restrained in a lateral direction by means of finger portions 28, it has considerable freedom of movement within passage 34 in a direction toward and away from the inlet 38. The pressurized fluid is not only directed axially of the passage 34, but outwardly from the sides thereof so that the yarn will normally be held out of engagement with the pins 16 and even from the side walls of finger elements 12.

It will be seen that yarn passing from a supply package to a take-up package and passing through yarn guide will upon increased tension therein, have the tendency to move sideways toward the inlet 38 against the pressurized fluid issuing therefrom. Additional yarn will thereby be paid out and the yarn tension maintained. Oppositely, upon the tendency of yarn tension to decrease, the yarn is urged by the fluid issuing from the yarn guide to move in a sideways direction away from the inlet 38, this action being such as to increase the yarn path length serving to temporarily store the yarn and to maintain tension at a desired level. The air pressure is controllable in any customary manner such that a desired value of yarn tension will always be maintained.

FIG. 2 is illustrative of a conventional take-up machine which has been modified to employ the invention herein disclosed. Said take-up or winding machine may be of the type disclosed in the patent to Keith, earlier cited. In practice with said machine a supply yarn Y is shown flowing from a suitable source (not illustrated). The yarn 42 is traversed to and fro of a core C by traverse means 48 to be wound into a package 44 supported for rotation on a spindle 45. As the yarn Y advances from its supply source to take-up package 44 it is wrapped partially about the strand control apparatus 10 of the instant invention. In the illustrated embodiment apparatus 10 is supported on a compensating arm 46 which, in turn, is mounted for pivotal movement about a substantially horizontal axis. The control apparatus is attached to the outer, free end of arm 46 by means of hollow bolt 22 and nut 30, and is directed downwardly, that is, in such a manner that the pressurized fluid issuing from inlet 38 is directed substantially downwardly.

In FIG. 4, yarn is seen engaged by the guide 10. The arm 46, so modified, operates in the identical manner disclosed in the aforecited Keith patent to maintain either a substantially constant or a progressively reduced tension in the strand of yarn being wound. However, the prior art has produced no known successful method of eliminating the variations in yarn tensions as the yarn Y is traversed across the take-up package by means of a first yarn guide 48 or other traversing mechanism. The reason for yarn tension variations is apparent from FIG. 3 which illustrates the winding package 44, and the fanning point from which the yarn is traversed, said fanning point being at apparatus 10 in FIG. 2. Clearly shown in FIG. 3 is the fanning motion effected by the yarn as it winds to and fro from position Y to Y to Y and returns. As the yarn strand traverses from its disposition at Y to its disposition at either Y or Y the rate of delivery of the yarn onto package 44 is increasing with an accompanying increase in tensile force of the yarn, and vice versa. Furthermore, the tensile force in the yarn is caused to vary a substantial amount at the ends of the package because of the abrupt changes in the winding formation at these reversal points. In the past, when the winding package 44 was rotating at a normal rate of surface speed, the inertia of arm 46 and its conventional yarn guide was found to be too great to effectively follow the varying yarn movements. For such action arm 46 would obviously have to pivot upwards when the yarn path approached the positions of Y and Y and settling downward when the yarn path approached the disposition of Y Previously, because of the inertia of the arm 46, it has been found that the yarn itself would extend or stretch to accommodate the changes or fluctuations in yarn path length, the result of which was to impair the quality of the yarn being wound.

This situation is remedied, however, by the use of the control apparatus 10 as shown in FIG. 4. When the yarn approaches the longer yarn path dispositions of either Y or Y and yarn tension increases accordingly, the yarn passing through strand control apparatus 10 is drawn upwards from a position not far from the tip end thereof to a position closer to the inlet 38. At each of the dispositions Y Y and Y and at each of the infinite number of intermediate dispositions which the yarn assumes as it is traversed to and fro of the package, the tension of the yarn is maintained substantially constant. The yarn glides on a cushion of air which has sufficient resilience to accommodate the yarn in all possible traversing dispositions while yet maintaining a single tension value therein during its winding movement.

A preferred modification of the combination compensator arm 46 and yarn guide 10 is compensator arm 52 and its associated mechanism shown in FIGS. 5 and 6. In this instance, a rotatable yarn engaging guide or wheel 54 assists the take-up roll 44 in drawing yarn from the source of supply and delivering it to the package being wound. Rather than being situated in the vertical manner of FIG. 4 with the passage 34 directed downwardly, yarn guide 10a is horizontally disposed. Therefore, passage 34a opens to the right, as seen in FIG. 5. It will be understood that the apparatus 10a is of generally the same construction as disclosed in FIGS. 1 and 4.

With continuing reference to FIGS. 5 and 6, yarn Y is seen to pass over grooved wheel 54 which is mounted for rotation on its axle 56. In turn axle 56 is suitably mounted on bracket 58 depending from arm 52. The yarn is directed about a guide pin 60, thence through the passage defined by spaced apart extension elements 28a, through another slotted yarn guide 62 fixed to bracket 58 at a position above arm 52, and finally is wound onto take-up package 44. Wheel 54 is provided with a plurality of vanes 64 formed about the circumference of an abutted portion 66 thereof. A nozzle 68, connected to source 32 of pressurized fluid, is positioned to direct a jet of fluid against the vanes for rotating the wheel. As in the previous embodiment, pressurized fluid from source 32 is also directed into the yarn receiving passage of yarn guide a. Although yarn Y is positively drawn from its source of supply by the take-up roll 44, rotating wheel 54 aids the drawing process, and is particularly effective in reducing yarn tension downstream thereof and increasing tension upstream thereof. This tension difference is adjustable over a wide range by varying the amount of air flow through nozzle Yarn guide 10a cooperates with wheel 54 to control tension in the identical manner described in the embodiment of FIG. 4. Upon a decrease in yarn tension, as when it approaches path Y (see FIG. 3), fluid issuing forth from chamber 18a impinges on the yarn forcing it toward the tip ends of extension members 28a whereby the yarn is required to assume a longer yarn path, and tension is maintained. Conversely, when yarn tension increases, that is upon approaching paths Y or Y the yarn is drawn toward inlet 38a against the pressurized fluid whereby the yarn path is shortened and tension is again maintained.

Another example of utilization of the invention resides in its combination with heating devices which may take the form disclosed in another Leesona Corporation, US. patent to W. A. Seem et al., No. 2,864,229, issued Dec. 16, 1958, or may be of any other desired construction. Referring to FIG. 7, reference numeral 70 generally indicates a typical heater which may be employed with conventional yarn texturizing apparatus. Grooved contact elements 72 through which thermoplastic yarn is drawn are heated in a customary fashion and perform to supply heat to the yarn both by conduction and by radiation. The insulating block 74 and the insulating covers 76 thermally isolate to a substantial degree the path of travel of the yarn from the surrounding atmosphere.

A plurality of grooved elements 72 are illustrated which permit the reversal of yarn being drawn through the heater. Although three such grooves are shown which permit two reversals of direction, as many grooves may be provided as desired, no particular member thereof being critical to the invention. For the effectivenes of the false twist texturizing processs, it is desirable that the entire length of yarn present within the confines of the heater 70 be fully effected by the action of a false twist spindle 78, that is, that the twist applied to the yarn in the regions proximate to the false twist spindle should migrate throughout the strand of yarn passing through the heater. The control apparatuses 10 of FIGS. 7 and 8 are constructed and operate in a manner identical to those embodiments previously described. A constant yarn tension is maintained throughout the length of yarn passing through the heater. Furthermore, by reason of the nearly unrestrained passage of yarn through and around the yarn guides, twist applied to the yarn by the false twist spindle adjacent one side of the heater progresses throughout the length of yarn located within the confines of the heater and beyond, to a twist restraining element or stop 80 adjacent the other side of the heater.

Use of the invention therefore in combination with the heater of a stretch yarn machine, permits the construction of a much more compact heating unit having a longer passage therethrough for higher yarn speeds without impairing the quality of the yarn.

A novel strand control apparatus has been disclosed herein which operates pneumatically and such that yarn is supported on a cushion of gaseous fluid and is substantially held out of engagement from the guide. Consequently, yarn tension is virtually unchanged from the upstream side to the downstream side thereof, and any condition, such as false twist, applied to the yarn upstream of the guide will be permitted to migrate to the downstream portions of the yarn without a noticeable decrease in that condition. Also disclosed herein is a novel form of pneumatically operated rotatable yarn guide which serves to increase yarn tension on the input side while reducing yarn tension on the output side thereof.

While preferred embodiments of the invention have been disclosed, the description is intended to be illustrative only and it is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined by the appended claims.

What is claimed is:

1. A guide for a strand of yarn, comprising means including a pair of opposed guide elements extending longitudinally in the same general direction, said elements being spaced apart to define a restrictive zone for receiving the strand and for passage of the strand transversely between the guide elements, a base portion extending between said elements and having opposite ends, means for guiding the strand as it passes between the elements and effectively preventing the advancing strand from contacting the base portion and including inlet means at said base portion for injecting fluid into said zone and against the strand in a direction substantially longitudinal between the elements at an intermediate portion and adjacent said ends of the base portion in a direction transverse between said elements and across said ends.

2. A guide as set forth in claim 1 in which said inlet means comprises elongated slot means extending longitudinally between said opposite ends of said base portion for the passage of the fluid into said zone.

3. A guide as set forth in claim 1 in which said base portion has guard means at said opposite ends for effectively preventing damage to the strand in the event that the strand engages the base portion.

4. A guide as set forth in claim 3 in which said guard means are rounded.

5. A guide for reversing the direction of an advancing strand of yarn, comprising means including a pair of opposed guide elements extending longitudinally in the same general direction, said elements being spaced apart to define a restrictive zone for receiving the strand and for passage of the strand transversely of the elements, a base portion extending between said elements and having opposite ends and guard means positioned adjacent the path of the advancing strand at said opposite ends for effectively preventing damage to the strand in the event that the strand engages the base portion, and means for guiding the strand as it passes between the elements and effectively preventing the advancing strand from contacting the base portion and including inlet means comprising elongated slot means extending longitudinally in said base portion between said opposite ends of said base portion for injecting fluid into said zone and against the strand with the fluid passing substantially longitudinally between the elements at an intermediate portion of the base portion and at said opposite ends of the base portion said fluid passing transversely between said elements and across said ends.

6. In a machine having regulating mechanism for maintaining substantially constant tension in an advancing strand of yarn, apparatus for operating said mechanism responsive to variation in tension of the advancing strand, comprising, an arm, mounting means for operatively attaching said arm to said mechanism for movement of the arm responsive to change in tension in the strand, and guide means on said arm for maintaining a cushion of fluid supporting said strand and compensating for fluctuations in tension in the strand.

7. Apparatus as set forth in claim 6 in which said guide means cooperates with said arm in maintaining substantially constant strand tension.

8. Apparatus as set forth in claim 6 in which said guide means is operable for guiding the strand through a path in which the strand substantially reverses direction.

9. Apparatus as set forth in claim 8 in which said guide means comprises a pair of opposed guide elements extending longitudinally in the same general direction and a base having opposite ends extending between said References Cited' elements and spacing said elements apart to define a UNITED STATES PATENTS restrictive Zone for receiving the strand for passage across said ends and transversely between the guide elements, 2646944 7/1953 Heffelfinger 242 150 and inlet means at said base for passing said fluid into 5 3047247 7/1962 242 45 said zone and against the strand to so support the strand 2741443 4/1956 Klem 242 147 as it passes through said zone. FOREIGN PATENTS 10. Apparatus as set forth in claim 9 in which said 1,140,629 3/1957 France base member has guard means at said opposite ends for efiectively preventing damage to the strand in the event 10 FRANK COHEN, i y rthat the strand engages the base member. MINTZ, Assistant