US2921358A

US2921358A - Apparatus for producing elasticized thermoplastic yarns

Info

Publication number: US2921358A
Application number: US561563A
Authority: US
Inventors: Fred W Cox; Cyril G Evans
Original assignee: Milliken Research Corp
Current assignee: Deering Milliken Research Corp; Milliken Research Corp
Priority date: 1956-01-26
Filing date: 1956-01-26
Publication date: 1960-01-19
Anticipated expiration: 1977-01-19

Description

Jan. 19, 1960 F. w. cox ET AL APPARATUS FOR PRODUCING ELASTICIZED THERMOPLASTIC YARNS 5 Sheets-Sheet 1 Filed Jan. 26, 1956 IN VEN TORS FRED W. COX CYRIL G. EVANS ATTORNEY Jan. 19, 1960' F. w. cox ET AL APPARATUS FOR PRODUCING ELASTICIZED THERMOPLASTIC YARNS 3 Sheets-Sheet 2 Filed Jan. 26, 1956 FIG-6- INVEN TORS FRED W. OOX BY CYRIL G. EVANS M am ATTORNEY Jan. 19, 1960 F. w. cox ETAL 2,921,358

APPARATUS FOR PRODUCING ELASTICIZED THERMOPLASTIC YARNS Filed Jan. 26, 1956 3 Sheets-Sheet 3 INVENTORS FRED W. COX CYRIL. G. EVANS WMMM ATTORNEY APPARATUS FOR PRQBUCKNG ELASTICIZED THERMlJfLASTitC YARNS Fred W. Cox, Pendieton, and (Zyril G. Evans, Clemson,

S.C., 'assignors to Deering Milliken Research Corporation, Pendleton, 5.0., a corporation of Delaware Application .lanuary 26, 1956, Serial No. 561,563

24 Qlaims. (Cl. 28-1) This invention relates to improved methods and apparatus for the manufacture of crinkled or coiled yarns having an elastic nature and, more particularly, the invention relates to the elasticization of yarns by passing the same through a sharply angular path under tension.

Apparatus for producing elasticized yarn by passing a thermoplastic strand under tension through an angular path is now well known in the art and constitutes a part of the subject matter of copending application, Serial Number 274,358, filed March 1, 1952. The type of apparatus most commonly employed for producing elasticized yarn by this procedure comprises a flattened heater strip or plate, against which the yarn is drawn in sliding frictional contact, and a blade membefpositioned with its edge in close proximity to the heater plate or strip so that the yarn can be drawn around the blade edge after being heated by its contact with the stationary heating means. While such apparatus is capable of producing an excellently elasticized yarn, the apparatus nevertheless leaves room for improvement in several respects.

A first disadvantage of the prior art apparatus is that it requires sliding frictional contact of the yarn with the surface of a yarn heater and this may result, in some instances, in objectionable abrasion of the yarn.

Still another disadvantage of the prior art apparatus is that in some instances the yarn cannot be supplied to the blade edge under a low enough tension to result in the highest degree of elasticization. In order for the yarn to be heated satisfactorily, it is necessary that it be in firm contact with the plate, and in some instances if one obtains sufficient contact with the plate to result in the yarn being adequately heated, the tension necessary to draw the yarn over the plate is in excess of that at which it is most advantageously drawn about the blade edge. This is particularly true if one attempts to utilize high linear yarn velocities since high velocities require a correspondingly greater length of contact with the heater plate or strip in order for the temperature of the yarn to be uniformly raised to a proper value for elasticization.

Still another disadvantage of the prior art apparatus is that it provides inadequate tension regulation in some instances and in particular when yarns of very low deniers are being processed. The difliculties of supplying a yarn end under a very low but constant tension will be ap parent to those skilled in the art and yet any variation in tension in the yarn being passed about the blade edge results in large differences in the degree of elasticization obtained. A non-uniformly elasticized yarn is not only objectionable because of its lower average degree of elasticity, but because it also tends to result in woven or knitted goods having a non-uniform appearance.

It is a primary object of this invention to provide yarn elasticizing apparatus which overcomes the above described disadvantages.

It is another object of the invention to provide apparatus which can constitute a component part of the Patented Jan. 19, 1960 equipment conventionally required in the production of thermoplastic yarns.

These as well as other objects of the invention are accomplished by apparatus comprising a roll having a yarn engaging peripheral surface, and means to position a blade means providing a yarn engaging edge adjacent the periphery of said roll such that an end of yarn passing between the periphery of the roll and said edge can be withdrawn from the surface of the roll about said edge in an angular path with said edge positioned at the apex of the angle. To heat the yarn so that it passes about the yarn engaging edge of the blade means at an elevated temperature, it is only necessary to heat at least a portion of the peripheral surface of the roll. The roll can conveniently constitute one element of a yarn storage device which in turn may constitute a part of the yarn production equipment now employed in the manufacture of thermoplastic yarns. For example, certain types of draw twisters may readily be modified according to this invention to thereby permit incorporation of yarn elasticization into the drawn twisting operation.

In View of the above, it will be appreciated that in apparatus according to this invention, the yarn need be in sliding frictional contact only with the edge of the blade means and further that the tension in the yarn passing about the blade edge may be as low as is desired. In other Words, the surface of the roll which heats the yarn also serves to advance the yarn at a reasonably constant rate so that the tension in the yarn as it passes about the blade edge can be regulated entirely by the yarn collecting or advancing means which withdraws the yarn from the blade edge.

Several specific embodiments of the invention will now be described with reference to the accompanying drawings in which:

Figure l is a front plan View of one form of apparatus according to this invention,

Figure 2 is an end view of a portion of the apparatus of Figure 1,

Figure 3 is a cross sectional view taken substantially along the line 3-3 in Figure 2,

Figure 4 is an enlarged view of the blade holding means utilized in the apparatus of Fiagure 1,

Figure 5 is a cross sectional view taken along the line 5-5 of Figure 4 of the drawings,

Figure 6 is a front plan view of a second form of apparatus according to the invention,

Figure 7 is a cross-sectional view taken along the line 7-7 of Figure 6,

Figure 8 is a front plan View of still another form of apparatus according to the invention,

Figure 9 is a cross sectional view of a portion of the apparatus of Figure 8 taken substantially along the line With reference to Figures 1 to 5 of the drawings, the reference numeral ll? indicates a conventional supply means for furnishing an end of yarn 11. The yarn supply means is here illustrated as comprising a bobbin, cop or the like but may be'any other suitable means for supplying a continuous filament yarn. For example, if the apparatus of this invention is to be constructed by modification of a draw twister, the yarn can be supplied directly from a hardening bath or drying chamber into which it is introduced from a spinnerette or the like.

The reference numeral 12 indicates a support member, which can be a part of a draw twister or spinning frame, and extending from the support member 12 is a stub shaft 14. The stub shaft 14 may be secured to the support member 12 in any suitable manner as for example by means of a nut 16. The reference numeral 18 generally indicates a roll member which is journaled for rotation on shaft 14 by means of anti-friction bear-r ings 20 and 22 and which is provided with a plurality of gear teeth 24 extending about the periphery of an end member 26. Means are provided for driving the roll 18 comprising a small gear 28 which meshes with the teeth 24 and which is carried by a driven shaft 30 illustrated as being journaled through the frame member 12.

The roll member 18 embodies two yarn engaging

drum portions

32 and 34 of different diameters. The larger drum portion 32, which may be formed of any suitable heat conducting material such as stainless steel, is provided with an annular flange 36 and is secured to end member 26 by any suitable means such as by screws 38. The smaller drum portion 34 is provided with an inwardly extending annular flange 40 which is secured to drum portion 32 by any suitable means such as screws 42. Preferably, for reasons which will subsequently become apparent, the portion 34 is thermally insulated'from portion 32, for example by means of a thin annular gasket 43 formed of a material having a low heat conductivity such as cork, or, if desired, the entire drum portion 34 may be formed of a material having a low coefficient of thermal conductivity.

Positioned within drum section 32 in close proximity to the inner surface thereof is an annular heater 44. The heater 44 is illustrated as being of the electrical resistance type and is designed to retain a portion of the yarn engaging surface of drum portion 32 at an elevated temperature. The heater is illustrated as being supported from stub shaft 14 by a series of support members 46 and is supplied with electrical power by means of electrical conductors 48 extending through an axial passage in stub shaft 14. A thermostat 50 is preferably provided for temperature regulation.

Journaled about a stub shaft 52 extending from frame member 12 is a second roll member generally indicated by the reference numeral 54. Roll member 54 is also provided with a first portion 56 and a second portion 58 of different diameters such that when the peripheral speed of portion 56 is equal to the peripheral speed of drum portion 32 of roll 18, the peripheral speed of section 58 of roll 54 will be equal to the peripheral speed of drum portion 34 of roll 18. Roll 54 is rotatable about an axis which is at an angle to the axis of rotation of roll 18 so that when yarn end 11 is wrapped a plurality of turns about the two rolls, adjacent wraps of yarn remain separated from each other as illustrated in the drawings, and it will be apparent that rolls 18 and 54 together constitute a yarn storage device of a conventional type.

Extending from member 12 is a support arm 60 which constitutes a part of a blade holding means to secure a blade member 62, having a yarn engaging edge 64, in operative position with the edge 64 positioned contiguous to the heated peripheral surface of the drum portion 32 of roll 18. The blade member 62 is illustrated as being seated in a suitable indentation in a plate member 66 carried by arm 60 and since it is generally advantageous that the blade 62 be retained at a low temperature relative to the drum portion 32 of roll 18, both plate member 66 and arm 60 are preferably formed of a material having a high specific thermal conductivity, such as bronze, so that heat is rapidly removed from the blade member. The blade member 62 is preferably mounted in such a manner that it is readily removable and is illustrated as being secured in position by a pair of clip members 68 attached to plate member 66 by any suitable means such as by screws 70.

The reference numeral 72 generally indicates a yarn takeup device here illustrated as comprising a conventional ring and traveler array. An apex guideor the like 74 guides the yarn end 11 into a yarn balloon from which it passes under a rotating traveler 76 and is wound upon a suitable bobbin 78. It will be understood that the takeup means may be of any conventional type and that in some instances it may be desirable to employ a takeup means of a type which does not result in the yarn being twisted.

In order to define a proper yarn path for yarn end 11, the apparatus is provided with several yarn guide means. A first guide means 80 is illustrated as being positioned immediately above the yarn supply 10 and permits the yarn end 11 to be withdrawn from the supply package in an over-end manner. A guide 82 and a guide 84 lead the yarn to a proper position on roll 18 and a guide 86 insures that the yarn is withdrawn from the roll 18 at a proper angle with respect to the axis of rotation of the roll. The yarn path between the

guides

82 and 84 and between the

guides

86 and 74 is illustrated as being discontinuous since, in many instances, it may be advantageous to conduct operations between these points that are not directly related to yarn elasticization. For example, it may be desirable to pass the yarn around a yarn storage device and a snubbing pin between the

guides

82 and 84 so that the yarn is permanently elongated in a conventional manner in the locality of the snubbing pin, or it may be desirable to pass the yarn end 11 to apparatus between

guides

86 and 74 for the application of a size or an antistatic agent.

In operation, an end of yarn from supply package10 is threaded through

guides

80, 82 and 84 to roll 18 and is then wrapped several turns (sufiicient to prevent the yarn from slipping to an appreciable extent) around the large diameter portion of

rolls

18 and 54. As best seen in Figure 2 of the drawings, the yarn end 11 is then passed between blade member 62 and the portion 32 of roll 18 and thereafter to the small diameter portion of roll 54 so that it passes, while at an elevated temperature, about edge 64 in a sharply angular manner with the edge 64 positioned at the apex of the angle. The position of blade member 62, relative to the periphery of portion 32 of roll 18, is preferably such that the yarn is caused to undergo a change of direction of at least about 90 in passing about the blade edge 64 and also such that the yarn has little opportunity to cool prior to the time that it contacts edge 64. In other words, if the edge 64 is positioned too great a distance from the periphery of portion 32 of roll 18, the yarn end 11 will cool to such an extent before passing about edge 64 that the highest degree of elasticization is not obtained and, as a general rule, the edge of the blade 62 should not be removed from the periphery of portion 32 of roll 18 a distance equal to more than about 20 times the diameter of the yarn to be processed. On the other hand, the edge 64 of blade 62 is too close to the periphery of portion 32 of roll 18, there may be insufiicient room for the yarn to freely pass between the roll 18 and the blade edge, and there is generally little advantage in attempting to place the blade 62 such that its edge is a distance equal to less than about twice the diameter of the yarn from the periphery of portion 32 of roll 18.

After passing about blade 62 to the small portion 58 of roll 54, the yarn end 11 is wrapped several turns around the smaller portions of

rolls

18 and 54 and is thereafter passed through

guides

86 and 74 to the takeup means 72. Passing the yarn from the large diameter portion of roll 18 about blade 62 and to the small diame' ter portion of roll 54 permits the yarn to shrink under the influence of heat immediately prior to the point that it contacts edge 64, and this not only relieves the yarn of stresses which would otherwise be present so that a higher degree of elasticization is obtained, but also places the yarn under a uniform tension as it is going about the blade edge.

It has been found that the tension in a moving end of continuous filament yarn overfed between two points and allowed to shrink under the influence of heat will remain relatively constant even with relatively large variations in the degree of overfeed and with slight variations in the temperature to which the yarn is heated. Therefore, the tension in the yarn passing about th edge 64 of blade 62 remains relatively constant during normal operation. It has further been found that the tension developed in a thermoplastic yarn contracting under the influence of heat is a near optimum tension for edge elasticization so that no supplemental tensioning or tension regulating devices are normally required. 01"; course, if one is processing a yarn which has been previously heat relaxed or which, for other reasons, is incapable of contracting under the influence of heat, then other means must be employed for controlling the tension in the yarn as it passes about the blade edge 64, and an overfeed arrangement cannot be readily employed.

The most advantageous degree of overfeed depends pri marily upon the degree of elasticization desired and upon the nature of the yarn being processed. If one desires the highest possible degree of elasticization, the diameter of portion 58 of roll 54 with respect to the diameter of portion 56 of roll 54 and the diameter of portion 34 of roll 18 relative to the diameter of portion 32 of roll 18 should be such that the yarn in passing from portion 32 of roll 18 to portion 56 of roll 54 is overfed substantially the maximum extent possible without the yarn becoming slack. While the maximum possible degree of overfeed will depend upon the type of yarn being processed, as a general rule it will be found to be from about 1% to 15% and, for example, with DuPont nylon type 200 is about 141%. There may, of course, be instances where one do sires to obtain less than the maximum possible degree of elasticity and in such instances the degree of elasticity obtained can be lessened by decreasing the amount of overfeed from the maximum possible. For example, with DuPont nylon type 200, a small measure of elasticity may be imparted by overfeeding the yarn only about 1% and intermediate degrees of elasticity may be imparted by increased overfeed until the maximum degree of elasticity is obtained with about overfeed.

With reference to Figures 6 and 7 which illustrate a modified form of apparatus, the reference numeral 83 indicates a support member which again may be part of a draw twisting or spinning frame. Journaled about a stub shaft 90 carried by frame member 38 is a roll member 92 having a yarn engaging peripheral surface 93 and having an end member 94 provided with peripheral gear teeth 95. The roll 92 may be driven by any suitable means such as a spur gear 96 meshing with the teeth 95 and carried by a driven shaft 93 journaled through frame ber 83.

Positioned within roll 92 closely adjacent the inner surface thereof is a cylindrical heater element 161) which is designed to retain the yarn engaging peripheral surface 93- of roll 92 at an elevated temperature. The heater element 1% may suitably be of the electrical resistance type and is supplied with electric power through conductors 1112 which enter the roll 92 through an axial passageway in st 1) shaft 90.

The reference numeral 1124 indicates a second roll member journaled about stub shaft 1% which is also carried by frame member 88. Roll member 104 is provided with a yarn engaging peripheral surface 165 and is rotatable about an axis which is at an angle to the axis of rotation of roll 92, so that when an end of yarn 1113 from any suitable yarn supply (not illustrated) is passed a pinrality of wraps around the rolls 92 and 1&4, adjacent wraps of yarn remain separated from each other. As with

rolls

18 and 54 in the apparatus illustrated in Figures l to 5 of the drawings, rolls 92 and 1114 together constitute a thread storage device of a conventional type.

The reference numeral 111 indicates a roll which has a yarn engaging peripheral surface 111 and which is jour naled for rotation on a stub shaft 112 also carried by frame member 38. Roll 111) is driven in any suitable manner and is here illustrated as including an end member 1214 which is provided with gear teeth which mesh with spur gear 96. A small roll 116 engages the peripheral surface of roll 110 and is carried by a pivot arm 11$ journaled on a small shaft 120 extending from frame member 88. A spring member 122, mounted about shaft 120, normally biases roll 116 into firm engagement with roll 110, and the two rolls functioning togetherprovide a constant linear rate yarn advancing means.

Rolls

116 and 110 may be made of any suitable material, but at least one of the rolls is preferably made of a resilient material, such as rubber, to lessen the slippage of an end of yarn passed between the nip formed by the ,two rolls and to prevent cross-sectional deformation of the yarn.

The reference numeral 124 represents a blade member, having a yarn engaging edge 125, which is retained in position, with the edge 125 in close proximity to theperipheral surface of roll 92, by means including an ann 126 extending from frame member 88. Blade member 124 is analogous to blade member 62 in the embodiment of Figures. 1 to 5 of the drawings and the statements earlier made with reference to the positioning of blade 62 relative to portion 32 of roll 18, apply equally well to the positioning of blade 124 with respect to the surface 93 of roll 92.

Guide means are provided to insure that the yarn'end 1% follows a proper path. A first yarn guide 128 carried by frame member 88 is provided for guiding the yarn about blade means 124 and to the surface 111 of roll 110. A second guide means 129, also carried by frame member 88, is provided to guide the yarn as itpasses between the

rolls

116 and 116.

In operation, the yarn end 1198 is wrapped a suflicient number of turns around rolls 92 and 104 to prevent substantial slippage, and is then withdrawn from the surface of roll 92 and passed about the yarn engaging edge of blade 124. The yarn end is then passed through guide 128 to roll 110 and thereafter between

rolls

110 and 116. The yarn is then passed through guide 129 and eventually to a conventional yarn takeup device, not illustrated. The yarn upon the surface of roll 92 is heated to a suitable temperature for elasticization by heater element 100 and upon rotation of

rolls

92 and 110, the end of yarn 108 is drawn about the edge 125 of blade member 124 in a sharply angular manner. In this embodiment of the invention, tension regulation is preferably provided by driving roll 110 such that it has a lower peripheral speed than roll 12 so that the yarn is allowed to contract under the influence of heat as it leaves roll 92 and passes about the edge of blade member 124. 7

With reference to Figures 8 and 9 of the drawings, which illustrate still another embodiment of the invention, the reference numeral 132 represents a suitable support member which carries a stub shaft 134. Iournaled about stub shaft 134 is a roll member 136 having a yarn engaging tapered drum portion 137 and anend member 13? which is provided with peripherally extending gear teeth.

The roll member 136 is driven in any suitable manner,

as for example, by a spur gear 139 mounted on a driven shaft 149 which is journaled through frame member 132.

Mounted within roll 136 is a heater element 141 having a shape corresponding to the inner surface .of the drum portion 137 of roll 136 and which is for the purpose of retaining the drum portion 137 at an elevated temperature. The heater element 141 may suitably be of the electrical resistance type and is supplied with power through electrical conductors 142.

Extending from frame member 132 at an angle to the axis of rotation of roll 136 is a pin member 143 which is preferably made of an abrasion resistant material and which is provided with a smooth yarn engaging surface. The roll 136 and pin member 143 constitute a yarn storage device of a conventional type, and when an end of yarn 144 from a conventional yarn supply, not illustrated, is passed a plurality of turns about the roll 136 and pin member 143, adjacent turns of yarn remain separated from each other by virtue of the pin member being at an angle to the axis of rotation of roll 136.

The reference numeral 146 indicates a blade memher, having a yarn engaging edge 147, which is positioned adjacent the tapered peripheral surface of the portion 137 of roll 136. The blade 146 is retained in position by means including a support arm 148 which extends from frame member 132. The blade member 146 is analogous to blade member 62 in the embodiment of Figures 1 to of the drawings and should be similarly positioned.

The reference numeral 150 generally indicates a constant tension takeup device here illustrated as comprising a takeup spool 152 positioned on a freely rotatable shaft 154 which extends between two slotted

frame members

156 and 158. Spool 152 is free to move up and down within limits and is driven by peripheral contact with a traverse roll 160 of a conventional type which is carried by a shaft 162 also extending between

frame members

156 and 158. The reference numeral 164 generally indicates a constant torque transmitting device which is carried by a stub shaft 166 extending from frame member 156 and which includes a first gear 168 coupled to a second gear 170 through a friction clutch. The friction clutch coupling may be conventional and is such that the torque urging rotation of gear 170 remains substantially constant regardless of the relative speeds of rotation of

gears

168 and 170. Means such as a nut 172 threaded on shaft 166 is preferably provided for varying the amount of torque transmitted to gear 170 from gear 168. Gear 168 is positively driven for example by engagement with a spur gear 174 carried by a driven shaft 176 journaled through frame member 156 and traverse roll 160 is driven through the constant torque device 164 by means of a gear 178 carried by shaft 162 which meshes with gear 170.

Guide means are provided to insure that the yarn follows a proper yarn path. A first guide means 180 is carried by frame member 132 and guides the yarn end 144 about blade member 146 in a proper manner. A second guide 181 directs the yarn to still another guide means 182 which is positioned centrally above the yarn takeup device 150 and guides the yarn to roller 160. Preferably, the guide 182 is removed from traverse roll 160 a distance which is large as compared to the length of the traverse roll since this minimizes tension fluctuations.

In operation, an end of yarn 144 is passed a plurality of turns about roll 136 and pin member 143 and is then withdrawn from roll 136 and passed about blade member 146 in a sharply angular manner. The yarn is thereafter passed about

guides

180 and 182, around roll 160 and to the takeup spool 152. The yarn is at an elevated temperature at the time it passes about the edge of blade member 146 as a result of the surface of roll 136 being heated by heater 141 so that, other conditions being proper, a permanent tendency to coil is imparted to the yarn as it is drawn about the blade edge. The tension.

in the yarn passing over the blade edge 147 is regulated by adjustment of the torque coupling 164, but once established at a proper value, remains substantially constant regardless of the amount of yarn on spool 152 as a result of the spool being surface driven.

It should be emphasized that a constant tension takeup means, such as indicated by the reference numeral 150 is generally advantageous only when the taper of drum portion 137 of roll 136 is such and the position of blade 146 with respect to portion 137 is such that any tendency for the yarn to contract has been completely eliminated before the yarn is withdrawn from portion 137 to be passed about blade edge 147. If the yarn has the ability to contract further at the time it is withdrawn from portion 137 of roll 136 to be passed about blade edge 147, it is generally advantageous to pass the yarn from the blade member to a constant linear rate yarn advancing or takeup means, such as illustrated in Figures,6 and 7 of the drawings, so that the contraction of the yarn controls the tension therein as it passes about the blade edge. Likewise, a tapered roll is suitable for use only with a yarn that originally has the ability to contract under the influence of heat, and if one is proc essing a yarn which has been previously thermally relaxed or for other reasons will not contract on heating, a cylindrical roll such as indicated by the reference numeral 92 in Figures 6 and 7 of the drawings should be employed in combination with a constant tension takeup means such as illustrated in Figure 8 of the drawmgs.

The apparatus of this invention is suitable for use with all yarns which can be edge elasticized with prior art equipment and when employing the new apparatus, it will be found that conventional values for process variables can be utilized. For example, the radius of curvature of the blade edge, the linear speed of the yarn about the blade edge, the temperature of the yarn as it passes about the edge and the tension in the yarn can all be conventional and, depending upon the type of yarn and other factors, the radius of curvature of the blade edge may suitably be from .05 to 4 or more times the diameter of the yarn, the yarn temperature can range from room temperature to the sticking temperature of the yarn, the linear speed of the yarn can be from substantially zero to 1,000 or more yards per minute, and the tension in the yarn can be from .05 to 2.5 gms. per denier. Of course, in some embodiments of the invention the yarn tension cannot readily be varied, but Where provision is made for varying the yarn tension, it may be set at any value conventionally employed with prior art edge elasticizing apparatus. Also, it is an advantage of the new apparatus that it permits higher than usual yarn velocities, but conventional yarn speeds can be employed if desired.

Having thus described our invention, what we desire to claim and secure by Letters Patent is:

1. Apparatus for processing a running length of yarn comprising in combination a driven roll, blade means providing a yarn engaging edge, means to position said blade means adjacent the periphery of said roll such that an end of yarn passing between the periphery of said roll and said edge can be withdrawn from the surface of said roll about said edge in an angular path with said edge positioned at the apex of the angle, and means to heat at least a portion of the yarn engaging surface of said roll so that the yarn passes about said edge while at an elevated temperature.

2. In an apparatus for processing a running length of yarn and including a yarn supply means and a yarn takeup means; a driven roll having a yarn engaging peripheral surface, means to heat at least a portion of said surface, blade means providing a yarn engaging edge adjacent said portion of said peripheral surface so that an end of yarn passing between the periphery of said roll and said edge can be withdrawn from the surface of said roll and passed, While at an elevated temperature, about said edge in a sharply angular manner.

3. Yarn processing apparatus comprising in combination a yarn storage device for continuously storing and advancing a running length of yarn, means for retaining a portion of the yarn engaging surface of said storage device at an elevated temperature to thereby heat at least a part of the yarn carried by said yarn storage device, said yarn storage device being constructed to receive yarn at a greater linear rate than that which the yarn is discharged from said storage device so that the heated yarn is permitted to contract, blade means having a yarn engaging edge, and means for positioning said blade such that said edge is in close proximity to the heated portion of said yarn engaging surface and such that the heated yarn can be passed about said edge in a sharply angular path with said edge positioned at the apex of the angle.

4. Apparatus according to claim 3 wherein said yam storage device comprises a pair of spaced rolls at least one of which is driven.

5. Apparatus according to claim 3 wherein said yarn storage device comprises at least one stepped roll having first and second portions of dilferent diameters and said heated portion of said yarn engaging surface constitutes at least a part of the peripheral surface of the portion of said stepped roll having the larger diameter.

6. Yarn processing apparatus comprising in combination a yarn storage device for continuously storing and advancing a running length of yarn, said storage device including at least one roll with a yarn engaging peripheral surface, means for retaining at least a portion of the peripheral surface of said roll at an elevated temperature to thereby heat the yarn in contact therewith, blade means having a yarn engaging edge, and means for positioning said blade such that said edge is contiguous to the heated surface of said roll so that the yarn can be withdrawn from the surface of said roll and passed about said edge in a sharply angular path While at an elevated temperature.

7. Apparatus according to claim 6 wherein said roll has a tapered portion of decreasing diameter and said edge is adjacent said tapered portion of the roll whereby the yarn is permitted to contract prior to the point in the yarn path at which it is passed about said edge.

8. Apparatus according to claim 7 including means to withdraw the yarn from said blade edge and collect the same under substantially constant tension.

9. Apparatus according to claim 6 wherein said roll is of substantially uniform diameter and including means to positively withdraw the yarn from said blade edge and advance the same at a substantially constant linear rate which is less than the peripheral speed of said roll whereby the yarn is allowed to contract between said last named means and the point at which it leaves said roll.

10. Apparatus for processing a running length of yarn comprising a first roll of substantially uniform diam eter, a second roll of substantially uniform diameter rotatable about an axis extending at an angle to the axis of rotation of said first roll so that when an end of yarn is passed a plurality of wraps about said rolls, adjacent wraps remain separated from each other, means for driving at least one of said rolls, means for retaining at least one portion of the yarn engaging surface of one of said rolls at an elevated temperature to thereby heat the yarn in contact therewith, a blade member having a yarn engaging edge, blade holding means for positioning said blade member such that said edge is contiguous to the heated portion of said yarn engaging surface so that the yarn can be withdrawn from said surface and passed, while at an elevated temperature, about said edge in a sharply angular path, and yarn advancing means to withdraw the yarn from said edge at a substantially constant linear rate which is less than the peripheral speed of said rolls, whereby the yarn is allowed to contract between said yarn advancing means and the point in the yarn path at which it leaves said yarn engaging surface.

11. Apparatus according to claim 10 wherein said yarn advancing means comprises a pair of rolls at least one of which is driven.

12. Apparatus according to claim 11 wherein the rolls of said advancing means form a nip for the yarn and at least one of the rolls is formed of a resilient material.

13. Apparatus according to claim 10 wherein the blade is so positioned that the yarn engaging edge is spaced from said heated portion of said yarn engaging surface a distance equal to from about 2 to times the diameter of the yarn to be processed and wherein said blade is so positioned that the yarn in passing about said edge undergoes a change of direction of at least about 90 degrees.

14. Apparatus for processing a running length of yarn comprising a first roll, a second roll rotatable about an axis extending at an angle to the axis of rotation of said first roll so that when an end of yarn is passed a plurality of wraps about said rolls, adjacent wraps remain separated from each other, means for driving at least one of said rolls, means for retaining at least one portion of the yarn engaging surface of one of said rolls at an elevated temperature to thereby heat the yarn in contact therewith, said rolls having corresponding sections of different diameter such that the heated yarn is permitted to contract, a blade member having a yarn engaging edge, and blade holding means for positioning said blade member such that said edge is contiguous to the heated portion of said yarn engaging surface so that the heated yarn can be withdrawn from said heated portion about said edge in a sharply angular path.

15. Apparatus for processing a running length of yarn comprising a pair of matched, stepped rolls having, in each instance, a first and second portion, said first portion of each roll being of greater diameter than said second portion, and said rolls being rotatable about axes at an angle to each other so that when an end of yarn is passed a plurality of wraps about said rolls, adjacent wraps remain separated from each other, means for driving at least one of said rolls, means for supplying an end of yarn to said rolls such that it enters a wrap around said first portions of said rolls, means for withdrawing said end of yarn from a wrap around said second portions of said rolls, means for heating at least a part of the peripheral surface of the large diameter portion of one of said rolls so that the yarn as it leaves the first portion of said one roll to travel to the second portion of the other of said rolls, is at an elevated temperature, blade means having a yarn engaging edge, and means for positioning said blade such that said edge is in close proximity to the heated peripheral surface of said one roll and such that the yarn while at an elevated temperature can be passed about said edge in a sharply angular path in traveling from the first portion of said one roll to the second portion of the other of said rolls.

16. Apparatus according to claim 15 wherein said heating means is thermostatically controlled to retain the heated peripheral surface of said first portion of said one roll at a substantially constant temperature.

17. Apparatus according to claim 15 wherein said second portion of said one roll is thermally insulated from said first portion of said one roll to thereby increase the temperature diiferential between the two portions of said one roll.

18. Apparatus according to claim 15 wherein the blade is so positioned that the yarn engaging edge is spaced from the heated peripheral surface of said one roll a distance equal to from about 2 to 20 times the diameter of the yarn to be processed, and wherein said blade is so positioned that the yarn in passing about said edge undergoes a change of direction of at least about degrees.

19. Apparatus for processing a running length of yarn comprising, in combination, a roll having a yarn engaging peripheral surface, means to heat at least an annular portion of said surface, blade means providing a yarn engaging edge, blade holding means to secure said blade means with said edge adjacent said annular portion of said roll surface, guide means to guide an end of yarn from said peripheral surface of said roll about said blade edge in an angular path with said edge positioned at the apex of the angle, and yarn advancing means to withdraw said yarn from said peripheral surface and about said blade edge.

20. Apparatus for processing a running length of yarn comprising, in combination, a driven roll having a yarn engaging peripheral surface, means to heat at least an annular portion of said peripheral surface, guide means to guide an end of yarn into contact with said peripheral surface, a blade holding means for securing a blade member having a yarn engaging edge with said edge positioned adjacent said annular portion of said peripheral surface, yarn advancing means for Withdrawing said yarn from said annular portion of said peripheral surface at a linear rate less than the surface speed of said driven roll to thereby result in said yarn being thermally contracted a constant selected amount as it passes from said peripheral surface to said yarn advancing means, and guide means, disposed in yarn flow relationship between said driven roll and said yarn advancing means, for guiding an end of yarn in an angular path about the edge of a blade member secured by said holding means.

21. Apparatus for processing a running length of yarn comprising, in combination, a stepped yarn heater roll having first and second portions of different diameters, means to heat at least a part of the peripheral surface of said roll, blade holding means to secure a blade member having a sharp edge such that said edge is proximate the peripheral surface of the larger diameter portion of said roll, and means to guide an end of yarn into contact with the peripheral surface of the larger diameter of said roll, about said edge in an acutely angular path with said edge positioned at the apex of the angle in said yarn path, and thereafter into contact with the peripheral surface of the portion of said roll of smaller diameter.

22. Apparatus for edge-crimping a running length of thermoplastic yarn comprising, in combination, a driven roll having a smooth surfaced annular portion, means to heat at least said smooth surfaced annular portion of said roll, a blade member having a sharp edge, blade holding means to secure said blade member in a fixed position such that said edge is proximate said annular portion of said roll and such that said blade member is spaced from said roll, so that a heated end of yarn in contact with said annular portion can be withdrawn therefrom and passed, while at an elevated temperature, in sliding frictional contact about said sharp edge in an angular path such that said edge is positioned at the apex of the angle in said yarn path.

23. Apparatus for edge-crimping a running length of thermoplastic yarn comprising, in combination, a roll having a smooth surfaced annular portion, means to heat at least said annular portion of said roll, a blade member having a sharp edge, blade holding means to secure said blade member in fixed spaced relationship to said roll with said sharp edge disposed proximate said annular portion, guide means for guiding a moving length of yarn into contact with said annular portion of said roll and thereafter about said edge in an acutely angular path such that said edge is disposed at the apex of the acute angle in said path and such that said yarn is in sliding frictional contact with said edge, and means to drive said roll such that said heated annular portion has a surface speed approximately equal to the linear rate of movement of the yarn in contact therewith.

24. Apparatus according to claim 23 wherein said roll is a stepped roll having portions of larger and smaller diameter, wherein said heated annular portion comprises the larger diameter portion of said stepped roll, and including guide means to guide said yarn into contact with the smaller diameter portion of said roll following its passage about said sharp edge.

References Cited in the file of this patent UNITED STATES PATENTS 1,988,313 Greene Ian. 15, 1935 2,156,244 Mahoney Apr. 25, 1939 2,244,415 Arnold June 3, 1941 2,318,998 Ingalls May 11, 1943 2,339,323 Field Ian. 18, 1944 2,464,502 Hall et al. Mar. 15, 1949 2,639,485 Ambler May 26, 1953 2,673,546 Newton Mar. 30, 1954 FOREIGN PATENTS 581,5 6 Great Britain Oct. 16, 1946 585,368 Great Britain Feb. 5, 1947