US3264812A

US3264812A - Apparatus for twisting yarn

Info

Publication number: US3264812A
Application number: US297570A
Authority: US
Inventors: Scragg Frederick
Original assignee: Ernest Scragg and Sons Ltd
Current assignee: Ernest Scragg and Sons Ltd
Priority date: 1962-02-26
Filing date: 1963-07-25
Publication date: 1966-08-09
Anticipated expiration: 1983-08-09
Also published as: DE1276520B; GB1027251A; BE628864A; CH410703A

Description

Aug. 9, 1966 I F. SCRAGG 3,264,312

APPARATUS FOR TWISTING YARN Filed July 25, 1963 4 Sheets-Sheet 1 FIG./

"IHIHIHHIHI 4 INVENTOR. derrk 56%;,

Aug. 9, 1966 F. SCRAGG 3,264,312

APPARATUS FOR TWISTING YARN Filed July 25, 1963 4 Sheets-Sheet 2 FIG. 2

. i x I f I I I I I l I I I I I I l I I I I I I I I 1 I 43 I g i I I I i "30 I I I I I I I I I I I I A INVENTOR.

Aug. 9, 1966 F. SCRAGG APPARATUS FOR TWISTING YARN 4 Sheets-Sheet 5 Filed July 25, 1963 I N VENTOR. Mmkk Aug. 9, W66 F. SCRAGG 3 ,264fl1l2 APPARATUS FOR TWISTI NG YARN Filed July 25, 1963 4 Sheets-Sheet 4 F /6. INVENTOR:

United States Patent The present invention relates to a yarn twisting apparatus.

This application is a continuation-in-part of now abandoned application Serial No. 270,463, filed April 3, 1963, and entitled Yarn Twisting Process and Apparatus.

For example, the present invention is applicable to that type of well-known device in which a yarn package is located on a nonrotating support or tube which has an 1 opening concentric with the package so that yarn can move from the package substantially along the axis thereof. The yarn is withdrawn from the package and passes downwardly along its axis, and then the yarn is rotated in the form of a balloon around the package by means of a bowl which is itself rotated and which is located beneath the package, the yarn being wound onto a receiving package after leaving the balloon. The yarn is drawn through the apparatus either by the rotation of the receiving package itself or by forwarding rollers located at or near the top of the balloon.

Structure of the above type is known in the art as a double twist spindle or as a two-for-one uptwister, inasmuch as two twists are inserted into the yarn for each revolution of the spindle. The rotary bowl has a cylindrical rotating surface on which part of the yarn is wrapped for the purpose of storing on the surface of the rotary bowl a portion of the yarn which, theoretically, is available for moving into or out of the balloon in order to maintain the length of the balloon constant so as to provide a yarn which has uniform twist characteristics. Thus, this storage device has been provided so as to compensate for variations in yarn tension by storing more or less yarn, with the stored yarn occupying a greater or lesser proportion of the circumference of the bowl surface, so that the length of the yarn in the balloon itself will remain constant.

In practice, however, it has been found that this construction does not result in providing a yarn having uniform twist characteristics. It has been found, instead, that in order to provide a twist of high uniformity the entire length of the yarn into which the twist is being inserted should be maintained substantially constant, and as a result the length of yarn which is stored on the cylindrical surface of the rotary bowl should also remain constant.

In two-for-one spindles of the type referred to above it is known to hold the carriage and bobbin which it carries stationary during operation of the spindle by means of an eccentrically loaded weight which is fixed to the balloon-guiding bowl in the case of a slightly tilted spindle or by means of a magnet and armature, there being a space in the latter arrangement between the magnet and armature through which the yarn balloon passes as the yarn leaves its guide. Such locating devices have been placed near the base of the bowl as being the most convenient position. However, it has been found that such a location tends to interfere with the free passage of the yarn during its movement from the stationary bobbin through the twisting zone to the take-up bobbin, and in addition the radius of operation of the magnet and armature to stabilize the bobbin and its support is relatively small.

it is accordingly a primary object of the present invention to provide a process and apparatus which will achieve ice a uniformity of the twist characteristics of a yarn which heretofore could not be achieved with the known apparatus.

It is also an object of the present invention to provide a process and apparatus which will maintain substantially constant the entire length of yarn into which the twist is inserted.

A further object of the present invention is to provid a device of the above type with a tension device which is simple in its construction and which is easy to adjust and which at the same time is self-cleaning, in that it is constructed in such a way that bits of flulf or fly cannot accummulate on the surfaces of the tensioning device.

It is furthermore an object of the present invention to provide a tension device which will suppress undesired oscillatory motion of a flyer during starting and stopping of the uptwister.

It is an additional object of the present invention to provide for an uptwister of the type referred to above a tensioning construction which will automatically compensate for variations in the tension of the yarn as it is withdrawn from a supply bobbin so as to maintain substantially constant the tension in the length of yarn into which the twist is inserted.

Still another object of the present invention is to provide a structure for holding the package carrying carriage stationary without in any way interfering with the movement of the yarn and also while providing a radius of operation for a holding magnet and armature which is great enough to stabilize the bobbin and its support without any difficulty while being able to use relatively small magnets and/or being able to provide a relatively large gap between the magnets and armatures.

With these objects in view the invention includes in a yarn twisting assembly, a support means which supports a supply bobbin from which yarn is adapted to be withdrawn while travelling along a given path to a receiving package. A yarn twisting means is located along the path of movement of the yarn to the receiving package, and in accordance with the present invention a tensioning means to also located along the path of movement of the yarn for tensioning the yarn as it moves from the supply bobbin to the receiving package.

Also with the above objects in view the invention includes in a two-for-one textile spindle assembly, a ballooncontrolling ring mounted on the supply bobbin carriage and another balloon-controlling ring mounted on the framework of the assembly, the two rings being located at or above the position of maximum free balloon diameter, and a magnet is located on or near one ring cooperating With an armature on or near the other ring so as to restrict or stabilize bobbin carriage movement.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a partly diagrammatic elevation of one possible embodiment of an uptwister according to the present invention;

FIG. 2 is a side elevation of a yarn tensioner capable of being used in the assembly of FIG. 1 and capable of automatically compensating for variations in the tension of the yarn as it is withdrawn from the supply package;

FIG. 3 is a partly sectional elevation showing the details of a tensioning means used with the embodiment of FIG. 1; and

FIG. 4 is a view of a structure similar to FIG. 1 but without the tensioning means and showing the details of the structure for holding the bobbin-carrying carriage stationary during operation of the spindle.

Referring to FIG. 1, there is illustrated therein part of a framework 2 of a two-for-one spindle machine, this framework 2 carrying a bracket 1 on which a spindle mount 3 is supported. A pivot pin 4 is carried by the bracket 1 and supports the spindle mount 3 for turning movement about the axis of the pivot pin 4, and the mount 3 has a limited turning range provided by the pivot 4.

The spindle mount 3 supports, in a suitable bearing, a rotary driven shaft 5 which forms a driven spindle, and this shaft 5 fixedly carries a pulley 6 which drives the spindle 5 by engaging a travelling belt 7 which, during operation of the machine, rotates the pulley 6 in order to rotate the spindle 5, whenever the pulley 6 engages the belt 7, which is to say whenever the mount 3 is placed in the operating position illustrated in FIG. 1. The mount 3 carries a suitable bearing in which a manually turnable shaft 8 is supported for turning movement, and this shaft 8 carries at its left end, which is not visible in FIG. 1, a projection which engages behind a projection 9 fixed to the bracket 1. Thus, when the shaft 8 is manually turned to the position where the projection thereof engages behind the projection 9, as shown in FIG. 1, the spindle mount 3 will be maintained in the illustrated operating position where the pulley 6 engages and is driven by the belt 7. The operator can turn the shaft 8 so as to release its projection from the projection 9, and now the mount 3 can turn in a clockwise direction, as viewed in FIG. 1, about the axis of the pivot 4, and in this way the pulley 6 is moved away from the belt 7 to stop the drive and thus facilitate withdrawal of an empty spool and replacement thereof by a full package. After the handle 8 is turned so as to release its projection from the projection 9, further rotation of the handle 8 in the same direction will move a brake 10, which is fixed to and projects radially from the bracket 8, through an opening in the mount 3 directly into engagement with the pulley 6 for braking the rotation thereof, and in this way it is possible to quickly bring the rotation of the spindle 5 to a stop. After the package is replaced, the entire assembly can be turned back to the position illustrated in FIG. 1, and then the handle 8 is turned in the opposite direction so that its projection will engage with the projection 9 and thus hold the assembly in the operative position. The projection 9 may be simply in the form of a block having at its side face which is not visible in FIG. 1 a vertical or slightly inclined groove or notch capable of receiving a pin projecting radially from the left end of the shaft 8 which is not visible in FIG. 1, and of course the shaft 8 fixedly carries suitable collars which permit the shaft 8 to be turned but prevent it from shifting axially in the bearings of the spindle mount 3.

The spindle 5 fixedly carries a bowl member 11 which is coaxial with the spindle 5 and rotates therewith, and the wall of the bowl 11 is formed with an opening in which a horizontal bush or sleeve 12 is fixedly mounted with is axis extending radially with respect to the spindle axis, so that the yarn may pass through the sleeve 12. In addition, the bowl 11 has a smooth, circular outer surface 13 on which part of the yarn becomes automatically wrapped during the twisting operations.

The upper end portion of the spindle 5, which is not visible in FIG. 1, is enlarged and is provided with a bearing which supports a package-supporting means 16, in the form of a cylindrical carriage, with the support means 16 positioned coaxially with respect to the spindle 5. Thus, the support means 16 is simply in the form of a vertical tube whose bottom end is received in the coaxial bearing of the shaft 5 so that in this way the shaft 5 is capable of rotating freely with respect to the support means 16. The support means 16 carries the supply bobbin or package 17 from which the yarn which is to be Cir twisted is withdrawn in the manner described below. The yarn which is withdrawn from the supply bobbin 17 passes from the supply bobbin upwardly to the top end of the tube 16 and then downwardly along the interior thereof, and from the interior of the package-supporting tube 16 the yarn passes in a manner well known in the art along the interior of the bowl 11 through the bush 12 to the exterior of the bowl 11, and the rotating spindle 5 forms from the yarn the balloon 44 which passes up through the stationary guide eye 45 to an unillustrated receiving package. The support 16 fixedly carries a light shield 18 which separates the ballon from the package, and it will be noted that the shield 18 extends along the entire length of the package 17. In addition, the shield 18, which is made of a suitable plastic or other nonmagnetic material, fixedly carries at an upper portion, adjacent to its top rim, or ring 123 (FIG. 4), a pair of magnetic armatures 26 (FIG. 4) which may be located at diametrically opposed parts of the shield 18. It is to be noted that the support means 16, the package 17, and the shield 18 do not rotate during the twisting operations.

The spindle mount 3 fixedly carries a post 20 which in turn carries a balloon-controlling ring 21, the latter surrounding the balloon so that the balloon 44 passes between the ring 21 and the shield 18. This ring 21 fixedly carries, at diametrically opposed portions, two permanent magnets 22 which cooperate magnetically with the above-mentioned armatures 26 adjacent the top of the shield 18 for preventing rotation of the shield and the package 17, as described above, and of course the balloon 44 can pass freely between the upper portion of the shield 13 and the magnets 22.

A tensioning device 23 (FIG. 3) is carried by the top of the support means 16 and is inserted into the upper portion thereof, and this tensioning device acts on the yarn just before it enters into the tube 16 to move downwardly therethrough into the bowl 11 as described above. Thus, an axially bored sleeve 30 is inserted into the top of the tube 16 and is provided with a shoulder which rests on the top edge of the tube 16. The upper part of the tube 30 carries a bearing 33 the outer race of which is freely turnable and carries the fiyer 25 shown in FIG. 1. In addition, the top of the tube 30 fixedly carries a lower tensioning element 32 in the form of an annular member having an upper annular surface located in a plane perpendicular to the axis of the tube 16, and this upper surface of the ring 32, which may be separated from and fixed to the tube 30 or which may be integral therewith, forms one of the tensioning surfaces of the tensioning device of the invention. The tensioning device includes a second tensioning element in the form of a disc 42 having a downwardly directed annular surface also located in a plane which is normal to the axis of the tube 16 and directly engaging the upper surface of the ring 32. This disc 42, in the embodiment of FIGS. 1 and 3, fixedly carries a stem 39 on which suitable weights 40 are mounted so that the disc 42 is urged toward the ring 32 with a given force. The yarn 24 which is withdrawn from the package 17 passes between and slidably engages the downwardly directed surface of the disc 42 adjacent to its outer periphery and the upwardly directed surface of the ring 32, and the weights 40 will provide a certain frictional resistance to the movement of the yarn in order to tension the yarn. Although it is possible to use a spring for loading the tensioner, instead of the weights 40, the weights 40 are preferred since they can be colored and seen through the balloon so that the particular loading is immediately visible. These weights 40 may simply be threaded onto a threaded portion of the stem 39 which is fixed to the upper tensioning disc, and this tensioning disc 42 which simply rests on top of the tensioning ring 32 is provided in its interior with a downwardly directed rim located within and spaced from the ring 32, as shown in FIG. 3, so that in this way lateral shifting of the tensioning disc 42 is avoided. The pair of

tensioning elements

32 and 42 are made preferably of hard steel. The yarn 24 passes through an eye at the end of a freely rotatable flyer or arm 25, and then from this eye the yarn passes between the tensioning surfaces, slidably engaging the latter, and then into the support 16 downwardly along the latter. The yarn 24 circles around the package 17 as it is withdrawn therefrom, and the flyer 25 turns freely with the yarn, and the yarn also turns around the axis of the stationary support 16 as it slides on the tension surfaces, thus moving around and around over all parts of the friction surfaces, and in this way these surfaces are kept clean. The tensioning device 23, in .addition to greatly increasing the uniformity of the twist, greatly reduces the tendency of the flyer 25 to oscillate undesirably when the spindle is started and stopped, so that in this way also lack of uniformity in the twist is avoided. Yarn tension variations of appreciable amount takes place during withdrawal of the yarn from the outside of the stationary package 17, this tension tending to increase as the yarn comes from the bottom of the package and decrease when it is withdrawn from the top. Moreover, the yarn tension varies as the package decreases in size during the unwinding of the yarn therefrom. The presence of the yarn tensioner of the invention at the top of the support 16 insulates these variations in the yarn tension from the part of the yarn which moves beyond the yarn tensioner down through the support 16, so that beyond the tensioning device of the invention the fluctuations in yarn tension resulting from removal of the yarn from the supply package do not influence the introduction of the twist into the yarn, and also, as pointed out above, the tension device assists in the suppression of undesired oscillatory motlon of the flyer during starting and stopping of the uptwister.

As the yarn is withdrawn from the package, its point of withdrawal rotates around the package and carries the flyer with it, and this rotary motion causes the yarn to slide in a rotary manner between the two tensioning surfaces of the tensioning device, so that the locus of the point of contact of the yarn with the friction surfaces a circle, and this point of contact constantly rotates around this circle. Inasmuch as the two friction surfaces of the tensioning device are of a constant radius, the rotary movement of the point of contact between the yarn and the surfaces causes no change in the tension applied to the yarn, but nevertheless, the wear is spread uniformly throughout these surfaces. Furthermore, since the fr ction surfaces impart a certain amount of circumferential drag to the yarn, the oscillatory motion of the flyer during starting, stopping, or running is reduced, so that in this way also more uniform tension results. In addition, because of the open nature and simplicity of the structure, yarn dust or fly cannot accumulate on any of the parts.

Thus, it is clear that the provision, in .accordance with the present invention, of a simple, noncompensating type of yarn tensioner greatly improves the uniformity of the twist which is introduced into the yarn. In accordance with the present invention, this uniformity is further increased with an even more preferred structure of the invention which is shown in detail in FIG. 2, this structure automatically compensating for tension variations in the yarn as it is withdrawn from the package, so that an even greater twist uniformity can be achieved.

The yarn tensioning device of FIG. 2 is simply inserted into the tube 16 in the manner described above. The flyer 34 corresponds to the flyer referred to above and includes an eye 43 through which the yarn passes from the supply bobbin 17. The rotary outer bearing ring 33 which carries the fiyer 34 also carries, fixedly, an upwardly extending relatively short arm which supports a pivot 36 which serves to pivotally support on the notary ring 33 an elongated lever 35 having two arms extending in opposite directions from the portion of the .lever 35 which is connected through the pivot 36 to the rotary bearing ring 33. The outer arm of the lever 35 threadedly carries a screw 33 which serves to adjustably fix to the lever 35 an elongated wire 37 also provided with an eye at its free end, as indicated in FIG. 2. The left end of the wire 37 is formed with a loop which is elongated and which has a width which is less than the diameter of the head of the screw 38, so that this screw 38 may be loosened in order to adjust the extent to which the wire 37 projects beyond the lever 35, and then the screw 38 may be tightened to fix the wire 37 to the lever 35, and in this way the position of the eye at the end of the wire 37 from the axis of the tensioning device can be regulated. The nner arm of the lever 35 fixedly carries the stem 39 which in this case is not fixed directly to the disc 42. Instead this stem 39 is fixed at its bottom end to an enlarged head whose downwardly directed surface presses on a ball member 41 which is carried by the disc 42, and in this way the weights 40 on the stem 39 serve to urge the lever 35 to turn in a counterclockwise direction, as viewed in FIG 2, these weights still urging the disc 42 downwardly against the ring 32 by engaging the ball 41. It will be noted that because of this construction the ring 33 together with the lever 35 and the stem 39 and weights 40 are capable of turning with respect to the nonrota-ting disc 42, the bottom end of the stem 39 in this case simply turning on the uppermost part of the hard metal ball 41 so that there is a minimum frictional resistance to the turning of the lever 35 with respect to the disc 42.

The yarn which comes from the supply package 17 passes through the eye 43 of the flyer 34 and then through the eye at the outer end of the wire 37, and from this latter eye the yarn passes between the friction surfaces of the

tensioning elements

32 and 42, and then down the axial bore of the insert 30 and downwardly along the interior of the support 16 into the bowl 11 as described above. ]if the tension in the yarn as it moves from the package 17 tends to increase, the yarn itself will act on the W111? 37 to tend to turn the lever 35 about the pivot 36 in a direction which will tend to raise the weights 40 away from the disc 42, so that in this way any increase in the tension of the yarn as it moves from the supply package will automatically reduce the extent to which the weights 40 urge the disc 42 downwardly against the ring 32, and thus automatic compensation for increasing tension in the yarn leaving the supply package is provided. Also, if the tension in the yarn leaving the supply package 17 should diminish, then the extent to which the yarn tends to turn the lever 35 in a direction which lifts the weights 40 away from the disc 42 is reduced, so these weights 42 act to an increasing extent for automatically increasing the frictional engagement of the surfaces of the

tensioning elements

32 and 42 with the yarn, so that in this way also the yarn tension is compensated for and with this construction a substantially constant yarn tension can be maintained.

As was pointed out above, the tension in the yarn tends to be greatest when the yarn is withdrawn from the bottom of the package and smallest when the yarn is withdrawn from a point part of the way down the surface of the package, and these tension variations will thus be automatically compensated, as well as tension variations which are relatively high when the package is of a maximum diameter. The insert 30 engages the inner surface of the tubular carriage 16 with a sliding fit which is of sufiicient tightness to prevent rotation of the member 30.

As was pointed out above, weights are preferred to springs for the purpose of loading the tensioning device since the weights can be colored and thus seen through the balloon so that the amount of loading is immediately visible, and in addition the amount of loading is exact and does not require calibration as would be the case if a loading spring were used.

It is known that the tension applied by a tensioner of this type is additive, so that if I is the input tension, I is the output tension, W is the applied load, and u is 7 the coeflicient of friction between the yarn and disc surfaces, then tz=2llW+t1 In this equation it is a simple matter to make certain that W does not vary, and after a short period of use it is found that u is also substantially constant. Therefore, in order to provide a constant value of t for a variable value of 1 it is essential to reduce the brake action by reducing the effect of W as t increases and by increasing the effect of W as t decreases. This result is achieved with the structure shown in FIG. 2 and described above, this structure operating so that the action of the lever 35 will decrease the loading on the disc 42 as t increases, and increase the loading as t decreases, the ratio of the lever-age being adjusted so that the loss in yarn tension caused by a loss Olf loading is equal to the increase in the tension t and the increase in tension caused by an increasing value of t will be accompanied by a compensating loss of loading. It is thus possible, within certain limits, to provide a yarn tensioner as described above which will maintain a constant out-put tension irrespective of input tension.

It has been found that this regulation of the yarn tension as it is drawn through the bush 12 and wraps around the bowl 13 is highly desirable. In all textile twisting processes it is obviously highly desirable that the twist imparted to the yarn shall be uniform per unit length of yarn. While twist iregularities of greater or lesser degree are of importance with some yarns more than with others, nevertheless, twist uniformity is always desirable. It has been found that in a conventional two-forone spindle which does not employ either a tensioner or a compensating tensione'r, the amount of yarn which wraps around bowl 11 before the yarn leaves the bowl to travel along the balloon varies with the degree of tension which is applied to the yarn as it enters the bowl. Thus, the higher the tension of the yarn entering the bowl, which is to say the higher the tension of the yarn leaving the supply bobbin, the greater the amount of wrap of the yarn on the bowl. Inasmuch as the tension of the yarn during its withdrawal from the supply package is constantly varying, the amount of yarn wrapped around the bowl also constantly varies. However, since the rate of application of the twist is constant, it follows that the twist per unit length must vary in proportion to the amount of Wrap-around of the yarn on the bowl.

The provision of a compensating tensioner of the type described above and shown in FIG. 2 greatly reduces the amount of twist variation per unit of length since the amount of wrap of the yarn on the bowl is substantially stabilized. It follows, therefore, that inasmuch as the amount of yarn receiving twist at any instant is constant and since the rate of application of twist is constant, the twist per unit length also is substantially constant.

After the yarn has passed through the balloon 44 and through the guide eye 45 it is wound onto a take-up package (not shown), and this package and its guiding mechanism are of a conventional type adapted to give the takeup package a constant peripheral speed.

The provision in earlier systems of a bowl storage device adapted for varying degrees of lap of the yarn around the bowl is believed to be the result of a misconception of the nature of twist insertion in a double twist system, and the reason for the success of the present invention is the discovery that the uniformity of twist in the final product depends upon the degree to which any mechanical force applied to the yarn during its passage through the system affects the rate and amount of propagation of twist through the yarn in the system. Thus, passage of the yarn under tension around the friction surfaces such as segments of cylinders affects the propagation of twist, and the effect is a function of the tension in the yarn, and the angle of lap. It follows that the degree of hindrance of twist propagation at the twist inserting device is affected not only by the condition at the direction-changing point where motion of the yarn ceases to be radial to the device and becomes circumferential (e.g., eyelet 12) but also by the angle of lap around the yarn storage device. Thus, by achieving a constant angle of lap, the rate of twist propagation is maintained constant. The effect of this process and apparatus of the invention is to avoid surging of twist from one point to another in the system, this surging, which takes place in other systems, causing gross short-term variations in twist content in the yarn.

FIG. 4 shows the pair of diametrically opposed magnetic armatures 26 carried by the shield 18 near its top rim ring 123. The package 17 and the shield 18 as well as the carriage 16 do not rotate during twisting, and the rim or ring 123 acts as an inner balloon guide. The pair of magnets 22 which are carried by the stationary outer balloon control ring 21 coact with the armatures 26 mounted on top of the shield 18 to prevent rotation of the shield and package 17. Thus, the balloon 44 passes between the inner rim ring 23 and the outer control ring 21 to the takeup package (not shown) via the top guide 45.

It will be noted that with this arrangement the balloon restricting means is located at or near the position of maximum free balloon diameter where the magnetic stabilizing means is located. Thus, the ring or rim portion 123 is located at or above the midposition of the bobbin 17, and although a pair of armatures 26 are shown fixed to the nonmagnetic shield 18 at least one armature is necessary, and at least one permanent magnet 22 cooperating therewith. Of course, it is possible to provide the inner ring 123 with the permanent magnet and the outer ring 21 with the armature provided that the magnetic components are so located as not to interfere with the free passage of the yarn. The pair of

rings

123 and 21 are provided with smooth balloon-engaging surfaces adapted to limit the expansion or contraction of the balloon to a required diameter, and the yarn may engage with either one or both of these rings during its passage from the inner rotating bobbin to the take-up bobbin.

By locating the magnet-armature combination in the position shown in FIG. 4 and described above, it is possible to insure the minimum amount of interference with the passage of the yarn and also to secure maximum radius of operation for the locating magnet so that either a relatively small magnet can be used or alternatively the magnet-armature spacing can be increased.

Inasmuch as it is possible in operation for the bobbin and its carriage to be jerked into rotary motion out of control of its locating magnet, the bobbin carriage can be provided with a smooth-surfaced projection, and the axis of the carriage can be positioned eccentrically with respect to the fixed ring in such a manner that undue rotation of the carriage causes engagement and jamming of the projection against the fixed ring.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of twisters differing from the types described above.

While the invention has been illustrated and described as embodied in yarn twisters, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalance of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a yarn twister, in combination, support means for supporting a bobbin from which yarn is withdrawn while moving along a given path; yarn twisting means located along said path and twisting the yarn as it moves therealong; tensioning means also located along said path and tensioning the yarn as it moves therealong; and automatic compensating means arranged along the path portion extending between said bobbin and said tensioning means and engaging the yarn as it moves along said path portion, said automatic compensating means being operatively connected to said tensioning means for automatically varying the tension applied by the latter to the yarn in a manner compensating for variations in the tension of the yarn as it is withdrawn from the bobbin.

2. In a yarn twister, in combination, support means for supporting a supply bobbin from which yarn is withdrawn while moving along a given path; yarn twisting means located along said path and twisting the yarn which is withdrawn from the bobbin; a pair of yarn tensioning members arranged coaxially with respect to the bobbin and respectively having friction surfaces directed toward each other and between which the yarn passes to be frictionally engaged thereby; loading means operatively connected to one of said tensioning members for urging the latter with a predetermined force toward the other of said members; and compensating means located along the path portion extending between said bobbin and said yarn tensioning members and engaging the yarn while it moves along said path portion, said compensating means operatively connected to the loaded tensioning member and engaged by the yarn as it is withdrawn from the bobbin for automatically decreasing the force with which said one tensioning member is urged toward the other tensioning member as the tension in the yarn leaving the bobbin increases and for automatically increasing the force with which said one tensioning member is urged toward the other tensioning member as the tension in the yarn leaving the bobbin decreases.

3. In a yarn twister, in combination, support means for supporting a supply bobbin from which yarn is withdrawn while moving along a given path; yarn twisting means located along said path and twisting the yarn as it moves therealong; a pair of yarn tensioning members respectively having friction surfaces directed toward each other and between which the yarn passes while moving along said path so as to be tensioned by engagement with said friction surfaces; loading means operatively connected to one of said tensioning members for urging the same toward the other of said members so as to provide a given frictional resistance to the movement of the yarn past said friction surf-aces; an elongated lever supported intermediate its ends, by said support means, for turning movement, said lever having one end portion operatively connected to the loaded tensioning member and an opposite end portion engaged by the yam as it is withdrawn from the bobbin and moves along said path, the yarn, if it increases in tension as it is withdrawn from the bobbin, acting on said lever for tending to turn the latter in a direction opposing the force of said loading means for reducing the frictional resistance to the movement of the yarn past said friction surfaces so as to compensate for the increase in the tension of the yarn leaving the bobbin, and if the tension in the yarn leaving the bobbin decreases, said lever releasing said loading means to act with a greater force on the loaded tensioning member so as to increase the frictional resistance to the movement of the yarn with respect to said friction surfaces and thus compensate for the reduction in the tension of the yarn leaving the bobbin.

4. In a yarn twister, in combination, support means supporting a supply bobbin from which yarn is adapted to be withdrawn while moving along a given path; rotary yarn twisting means coaxial with said bobbin and twisting the yarn as it moves along said path, said rotary twisting means forming a balloon of the yarn around said bobbin; drive means driving said twisting means at a constant rate; adjustable tensioning means engaging the yarn in advance of said twisting means; and automatic compensating means located along the portion of the path of the yarn between said supply bobbin and said tensioning means and engaging the yarn as it moves along said path portion, said automatic compensating means operatively connected with said tensioning means for maintaining a substantially constant tension in the yarn as it moves to said twisting means, whereby the length of the yarn in the balloon remains substantially constant.

5. In a two-for-one textile spindle assembly, in combination, a stationary framework; a stationary outer balloon-controlling ring carried by said framework; a supply bobbin carriage substantially coaxial with said outer ring; an inner balloon-controlling ring mounted on said carriage, said outer and inner rings being located at least at an elevation as high as the maximum free ballon diameter; at least one magnet carried by one of said rings; and at least one armature carried by the other of said rings to cooperate with said magnet for stabilizing bobbin carriage movement.

6. A two-for-one textile spindle assembly, comprising, in combination, a stationary framework; an outer ballooncontrolling ring carried by said framework; a supply bobbin carriage substantially coaxial with said outer ring; an inner balloon-controlling ring carried by said carriage, said rings being located at least at an elevation as high as the position of maximum free balloon diameter; a pair of magnets mounted on said outer ring; and a pair of armatures mounted on said inner ring and cooperating with said magnets for restricting and stabilizing bobbincarriage movement.

7. A two-for-one textile spindle assembly, comprising, in combination, a stationary framework; an outer ballooncontrolling ring carried by said framework; a supply bobbin carriage substantially coaxial with said outer ring; an inner balloon-controlling ring carried by said carriage, said rings being located at least at an elevation as high as the position of maximum free balloon diameter; a pair of magnets mounted on said outer ring; and a pair of armatures mounted on said inner ring and cooperating with said magnets for restricting and stabilizing bobbinoarriage movement, said magnets being diametrically opposed with respect to each other and said armatures also being diametrically opposed with respect to each other.

8. A two-for-one textile spindle assembly, comprising, in combination, a stationary framework; an outer ballooncontrolling ring carried by said framework; a supply bobbin carriage substantially coaxial with said outer ring and carrying a substantially cylindrical balloon shield concentric with said carriage and said outer ring, and said shield terminating in an inner balloon-controlling ring, said ringsbeing located at least at an elevation as high as the position of maximum free balloon diameter; and a magnet and armature one of which is carried by one of said rings and the other of which is carried by the other of said rings and cooperating with each other for restricting and stabilizing bobbin carriage movement.

9. In a yarn twister, in combination, a tubular member having an annular end face; a tensioning member having an annular tension surface aligned with and located adjacent said end face so that yarn passing between said end face and annular tension surface will be tensioned by frictional engagement therewith; guide means freely rotatable about said tubular member for guiding the yarnbetween said end face and tension surface; urging means acting on said tensioning member for urging said annular surface thereof toward said end face of said tubular member; and lever means carried by said guide means for engaging yarn moving therefrom to said end face of said tubular member, said lever means being operatively connected to said urging means for acting on the latter to reduce the force with which said tensioning member is urged toward said end face as the tension in the yarn moving toward said end face increases and to increase the force with which said tensioning member is urged toward said end face as the tension in the yarn moving toward said end face decreases, whereby the tension in the yarn moving beyond said end face is substantially constant.

References Cited by the Examiner UNITED STATES PATENTS 1,985,665 12/1934 Munson 242-150 2,646,943 7/1953 Lindsay 242-150 10 2,745,610 5/1956 Reyes 242150 MERVIN STEIN, Primary Examiner.

Claims

6. A TWO-FOR-ONE TEXTILE SPINDLE ASSEMBLY, COMPRISING IN COMBINATION, A STATIONARY FRAMEWORK; AN OUTER BALLOONCONTROLLING RING CARRIED BY SAID FRAMEWORK; A SUPPLY BOBBIN CARRIAGE SUBSTANTIALLY COAXIAL WITH SAID OUTER RING; AN INNER BALLOON-CONTROLLING RING CARRIED BY SAID CARRIAGE, SAID RINGS BEING LOCATED AT LEAST AT AN ELEVATION AS HIGH AS THE POSITION OF MAXIMUM FREE BALLOON DIAMETER; A PAIR OF MAGNETS MOUNTED ON SAID OUTER RING; AND A PAIR OF ARMATURES MOUNTED ON SAID INNER RING AND COOPERATING WITH SAID MAGNETS FOR RESTRICTING AND STABILIZING BOBBINCARRIAGE MOVEMENT.