US2970424A

US2970424A - Yarn twisting

Info

Publication number: US2970424A
Application number: US773595A
Authority: US
Inventors: Ernest K Bauer
Original assignee: American Viscose Corp
Current assignee: Akzo Nobel UK PLC
Priority date: 1958-11-13
Filing date: 1958-11-13
Publication date: 1961-02-07
Anticipated expiration: 1978-02-07

Description

Feb. 7, 1961 E. K. BAUER YARN TWISTING Filed Nov. 15, 1958 United States Patent O YARN TWISTING Filed Nov. 13, 1958, Ser. No. 773,595

4 Claims. (Cl. 5793) This invention relates to the art of twisting or throwing yarn and in its more particular aspects to a method and means for controlling the operation of a yarn twisting machine.

As originally packaged, yarns of various materials ordinarily do not contain as high a degree of twist as is desired when the yarn is to be formed into a fabric. For example, acetate yarn is ordinarily first collected on a bobbin or spool in the form of a zero or substantially zero-twist continuous multi-filament strand. Beforesuch a strand is woven, knitted'or otherwise made into a fabric it must be twisted, the amount of twist depending upon the denier of the yarn and the type of fabric it is desired to make.

While there are several common types of machines used for twisting yarn, the present invention will be explained in connection with what is known as an uptwister. In an up-twisting operation, the yarn is withdrawn upwardly from a vertically arranged rotating bobbin or other package and wound onto-a second package having a horizontal axis. The ratio of the speed of rotation of the bobbin to the speed of withdrawal of the yarn therefrom determines the degree of twist inserted into the yarn. For example, if the bobbin is rotated at one hundred revolutions per second and Withdrawn at the rate of ten inches per second, one hundred turns of twist will be inserted into each ten inches of the yarn, or ten turns per inch. When the yarn is being twisted more than about ten turns per inch it has heretofore been highly desirable to perform the twisting continuously until all the yarn was withdrawn from the bobbin because when the operation was stopped while there was yarn remaining on the bobbin the twist in the yarn between the bobbin and the package being Awound would cause the yarn to corkscrew or form loops which would often become caught on the various guides between the two packages when the operation was resumed. Inasmuch as one standard type of up-twister accommodates one hundred and eighty-four strands of yarn on packages weighing two pounds, it will be understood that the machine must operate rfor several hours to empty the bobbins' and that should it be necessary or desirable to shut down the machine before the bobbins are emptied there are apt to be a great many entanglements when the machine is started up again. f

Applicant has discovered that the above-mentioned rice of the bobbin being subsequently simultaneously discon.` tinued.

It is an object of this invention to provide a method and apparatus for preventing undesirable loop formation in a twisted yarn strand when the twisting operation is discontinued before the strand is completely withdrawn from the supply package.

corkscrewing or loop formation can be prevented by reducing the amount of twist briefly before stopping the machine. That is to say, the twist is briefly reduced to such a value that the yarnn will'not form into loops when the machine is stopped. The actual value to which the twist is reduced will of course depend'upon the type and denier of the yarn. According to this invention, the reduction of the turns of twist is accomplished by increasing the speed of withdrawal of the yarn from the bobbin while maintaining the speed lof rotation ofthe bobbin at a constant value, the withdrawal'of the yarn and rotation It is a further object of the invention to provide means for controlling the speed of withdrawal of yarn from a rotating package independently of the speed of rotation of the package.

Other and further objects, features and advantages of the invention will become apparent as the description of a preferred embodiment thereof proceeds.

Referring now to the drawing:

Figure 1 is a schematic view transversely of a yarn twisting machine; and

Figure 2 is a sectional view taken along the line II--II of Figure 1.

The twisting machine includes a main drive shaft 10 extending the entire length of the machine and supported in bearings carried by the framework 11. Mounted in pairs on opposite sides of the machine are

spindles

12 and 13, only one spindle'of each pair being shown. A continuous'belt 14 extends around a drive wheel 15 secured to the main drive shaft 10.and drivingly engages'the

spindles

12 and 13, suitable guiding and

tensioning rollers

16 and 17 being provided for controlling the flight of the belt. Altogether, each machine has forty-six of the spindles 12 and a like number of spindles 13, each belt 14 driving two of the spindles 12 and two of the spindles 13. These figures are menotioned merely to give an idea of the size of a typical machine and hereafter only the mechanism actually shown in the drawing will be referred to. Supply packages or

bobbins

18 and 19 are mounted on the

spindles

12 and 13 respectively for rotation therewith, the yarn proceeding upwardly from these bobbins and being wound into tubular packages 20'and 21 during the twisting operation.

For driving the packages 20` and 21 the following mechanism is provided. Secured to the main drive shaft 10 is a gear 22 which meshes with a larger gear 23 mounted on a stub shaft 24 fixed in the framework 11, as shown in Figure 2. The gear 23 is formed with a hub 25 to which is fixed, as by welding or otherwise, a sheave or Vpulley 26. The V-pulley 26 is connected by a V-belt 27 to a compound adjustable pulley generally indicated at 28 and which includes a fixed central double flange 29. The belt 27 lies between the fixed flange 29 and an adjustable flange 30 which is urged by a spring 31 toward the flange'29, the belt 27 thus serving to drive the coinpound pulley 28.v An adjustable flange 32 is urged by a spring 33 toward the opposite face of the double flange 29 and a V-belt 34 rides between the

flanges

29 and 32. The belt 34 drivingly engages a V-pulley 35 secured to a sleeve 36 rotatably mounted upon a stub shaft 37. A driving pinion 38 is secured to the sleeve 36 and meshes with a gear 39 which in turn is meshed with a gear 40 secured to a shaft 41, which shaft extends the entire length of the machine. The gear 39 is also meshed with an idler 42 drivingly engaging a gear 43 fixed to a shaft 44 extending parallel to the shaft 41 for the entire length of the machine. Secured to the shaft41 at spaced points therealong corresponding to the positions of the packages 21 are drive rollers 45, only one of which is shown, and corresponding drive rollers 46 are secured to the shaft 44 for driving the packages 20.

The yarn from the bobbin 18 is led upwardly from the bobbin and through a pigtail guide 47 located axially of said bobbin, through a tension guide 48 and a traverse guide-49 which leads the yarn into the nipv between the package and the drive roller 46. The package 20, or actually the core on which the package is formed, is provided with an axial shaft 50 resting in slots provided in brackets 51 at each end of the package. As thesize of the package increases from that shown in a full line to its nal size shown in a dotted line, the spindle Si) rides up in theV slots in the brackets Slt. Thus, the package 20 is driven through surface contact with the drive roller 46 so that the linear speed of the yarn does not vary as the package diameter increases. The yarn from the bobbin 19 is led to the package 21 and taken up in a similar manner.

The elements of the driving train extending between the main drive shaft itl and the drive rollers 45 and 46 are so selected that with tlie compound pulley 28 in the position shown in the drawing the speeds of the drive rollers i5 and 46 will be such that the yarn will be withdrawn from the bobbins i3 and i9 at speeds which permit the rotating bobbins to insert the desired degree of twist into the yarn. When certain yarns are twisted more than about ten turns per inch they must be maintained under tension or the twist will cause the yarn to corkscrew or form loops. vision is made to maintain the tension on the yarn between each bobbin and its wind-up package, it is highly undesirable to stop the operation while there is yarn remaining on the bobbins and while the yarn between the bobbin and wind-up package is highly twisted. However, when the bobbins contain a considerable length of yarn requiring several hours to unwind, it is sometimes' necessary or at least desirable to discontinue the operation for a while before the bobbins have been emptied. The present invention provides a means whereby the twisting operation may be safely discontinued before the bobbins are emptied and this is accomplished by reducing the twist to a safe value for a brief period before stopping the machine and thus eliminating the need for special tensioning apparatus.

It has been pointed out that the factors determining the degree of twist are the speed of the bobbin and the speed of withdrawal of the yarn from the bobbin. That is to say, the number of turns of twist depends upon how many times the bobbin rotates during the time that each unit of yarn is withdrawn. The present invention provides a means for increasing the speed of withdrawal while maintaining the bobbin speed constant to thus reduce the twist. When the twist is then reduced to a point where the yarn will not corkscrew when the tension is released, the machine may be stopped without danger of the yarn becoming entangled.

Twisting machines generally make some provision for changing the speed of the wind-up packages independently of the speed of the bobbins so that the same machine may be used from time to time with different yarns requ'iring different degrees of twist but this generally involves some mechanical manipulation such as replacing gears or the like. With the present invention this change can be made by the machine operator while the machine is running. The compound pulley 28 is rotatable upon a shaft 52 carried by an arm 53 of a bell crank which is pivotally mountedat 54 on a bracket 5S. The other arm 56 of the bell crank carries a nut through which is threaded an operating shaft 57 rotatably mounted in a stationary bearing 58 provided in the bracket 55. An

operating handle 59 is secured to the shaft 57 whereby said shaft may be turned to cause the threaded portion thereof to move the bell crank and thereby vary the position ofthe pulley 2S. Lock nuts 60 and 61 may be provided on the shaft 57 to limit the movement of the pulley.

With the pulley 28 in the position shown in the drawing, the drive ratio between pulleys 26 and 35 is such that the entire driving train between the main shaft 10 and the drive rollers 45 and 46 will operate said driving Thus, unless some prorollers at the normally desired speed. By turning the handle 59 so as to rotate the shaft 57 in a clockwise direction the compound pulley 28 will be moved generally away from the pulley 26 and toward the pulley 35. This will increase the tension on the V-belt 27 and cause it to move inwardly toward the axis of the pulley 28, the spring 31 permitting thelmovable ange 30 to move away from the double flange 29. At the same time the tension in the belt 34 will be decreased so that the spring 33 may press the flange 32 closer to the ilange 29 and cause the belt 34 to ride outwardly between the facing surfaces of said flanges. Thus, movement of the pulley 28 toward the pulley 35 is etfective to decrease the driving radius of that portion of the pulley comprised of the

anges

29 and 30 vand to increase the driving radius of that portion of the pulley consisting of the

flanges

29 and 32. The belt 27 therefore drives the pulley 28 at a greater speed than before and in turn the belt 3,4 drives the pulley 35 at an increased speed. This ofcourse increases the speed of the drive rollers 45 and 46 and thus increases the speed of withdrawal of the yarn strands from the bobbins.

in practice, when it is desired to stop the machine, the operator will turn the handle 59 in the direction to swing the compound pulley 28 toward the pulley 35 just prior to stopping the machine. By proper adjustment of the lock nut 61, the operator may turn the handle as far as it will go and this will position the pulley 28 at the point where the number of turns of twist will be such that when the operator very shortly thereafter stops the machine, the yarn will not corkscrew or loop due to the lack of tension between the bobbins and the wind-up packages. When the machine is to be subsequently started up, the yarn between the bobbin and wind-up package will of course contain less twist than the yarn already on the wind-up package and to increase the twist in this portion of the strand the operator turns the handle S9 to position the pulley 28 closer to the pulley 26, the lock nut 60 determining the proper position for the pulley to give the required amount of extra twist.V Very shortly after starting the machine, the operator moves the pulley 28 in its center position shown in the drawing so as to re-establish the desired ratio between bobbin speed and wind-up speed.

Having thus described a preferred embodiment of the invention, what is claimed is:

1. In a yarn twisting machine, a rotatable support for a yarn package, means for drivingly connecting a yam package to said support, wind-up means for withdrawing yarn from a package mounted on said support and forming the yarn into a second package, drive means for rotating said support to impart twist to the yarn being withdrawn from the package mounted thereon, a driving train connecting said drive means to said wind-up means, said driving train comprising speed control means normally set to rotate said wind-up means at a predetermined speed less than the speed of said support so that a relatively high. predetermined number of turns of twist will be inserted into the yarn, and manual means for adjusting said speed control means to cause an increase in the speed of said wind-up means whereby the number of turns of twist may be reduced prior to stopping the machine and thereby avoid the formation of loops in the yarn` between the package and the wind-up means which would ensue from stopping the machine with highly twisted yarn between the package and the wind-up means.

2. In a yarn twisting machine, a rotatable support for a yarn package, means for drivingly connecting a yarn package to said support, wind-up means for withdrawing yarn from a package mounted on said support and forming the yarn into a second package, drive means for rotating said support to impart twist to the yarn being withdrawn therefrom, a driving train connecting said drive means to said wind-up means, said driving train comprising a fixed-axis V-pulley driven by said vdrive means, a

second V-pulley mounted on a movably mounted axis, a V-belt for driving said second V-pulley fromsaid tixedaxis V-pulley, means drivingly connecting said second V- pulley to said wind-up means, said second V-pulley having a xed ange and a slidably mounted ange, a spring urging said slidably mounted flange toward said fixed flange, the axis of said second V-pulley being normally so positioned that said V-belt will engage said V-pulley at a driving radius such that said driving train will rotate said wind-up means at a predetermined speed whereby a predetermined number of turns of twist will be inserted into the yarn, and means for moving the axis of said second V- pulley away from said fixed-axis V-pulley whereby the driving radius of said second V-pulley will be reduced to thereby increase the speed thereof and correspondingly increase the speed of said wind-up means to thus reduce the number of turns of twist inserted into the yarn.

3. In a yarn twisting operation wherein a relatively high normal degree of twist is inserted into a yarn strand by withdrawing the yarn by a wind-up means normally operating at a certain speed from a rotating supply package normally operating at a certain other speed and wherein the degree of twist depends upon the speed ratio between the supply package and the wind-up means; the method of avoiding undesirable loop formation in the yarn when the operation is to be stopped and restarted before the supply package is emptied, comprising briey increasing the speed of the wind-up means while maintaining the speed of the supply package constant before stopping the operation to thereby reduce the degree of twist to a point 6 where the yarn will not form loops when the operation is stopped.

4. In a yarn twisting operation wherein a relatively high normal degree of twist is inserted into a yarn strand by withdrawing the yarn by a wind-up means normally operating at a certain speed from a rotating supply package normally operating at a certain other speed and wherein the degree of twist depends upon the speed ratio between the supply package and the wind-up means; the method of avoiding undesirable loop formation in the yarn when the operation is to be stopped and re-started before the supply package is emptied, comprising briefly increasing the speed of the wind-up means while maintaining the speed of the supply package constant before stopping the operation to thereby reduce the degree of twist to a point where the yarn will not form loops when the operation is stopped, and operating the wind-up at a higher than normal speed for a brief period after the operation is re-started.

References Cited in the le of this patent UNITED STATES PATENTS 1,012,946 Weinbrenner Dec. 26, 1911 2,061,614 Dickie et al Nov. 24, 1936 2,247,481 Cooper July 1, 1941 2,249.404 Sunderland July l5, 1941 2,293,955 Van Dobbenburgh Aug. 25, 1942 2,654,212 Kelliher Oct. 6, 1953 2,785,527 Lewellen et al Mar. 19, 1957