In this system higher the count finer the yarn. Tex: Count is the Tex system is the wt. Denier: It is the wt in gm of m of yarn. For example, If 1 pound of yarn contains 20 hanks of yards, then English cotton count will be 20Ne. Metric system: It is defined as no of hank m per kg.
Each process in a spinning mill contributes a part to the evenness. This term is used commonly to express twist level of the yarn. There is no limitation in the length of the thin place. Better yarn has less thin place. Frequently-occurring thick places exhibit a length that corresponds with the mean staple length of the fibre. It can either be a fiber nep, a seed coat nep or a trash particle. The increase for neps is calculated to a reference length of 1mm.
They can be a bunch of entangled fibres commonly not bigger than pin ball head. Micronaire Mic. A fiber sample of constant weight is measured by passing air through the fibers and measuring the drop in pressure. The micronaire scale has been established empirically with a standard set of cottons and is not linear.
Other factors such as fineness and maturity have an influence on micronaire results. These fibers can be natural fibers cotton or artificial fibers polyester. Final product of spinning is yarn.
Spinning is the foundation process and all the subsequent value added processes such as Weaving, Knitting, Garments and Denims are depend upon it. Any variation in quality of spinning product directly affects the entire value chain. A brief discussion of function of the major machineries used in Square textile Complex has been described below: Blow Room: Blow room is the starting of the spinning operation.
It is the section where supplied compressed bale is turn into a uniform lap of particular length. The basic functions of blow room are opening, cleaning, dust removal, blending and evenly feeding the material on the card. The machineries required to carry out these functions are: 1. Cotton Bale 2. Unicleane or Cleaning Machine 3. Unimix or Mixing Machine 4. Fine Cleaner 5. Condenser 6. Carding 7. It could be automatic or manual.
Unifloc is an automatic bale opener machine that plucks raw cotton in lump form and sends these to clean through air transportation for coarse cleaning. From Figure B , the major parts of automatic bale opener are: 1.
Control unit 2. Channel for cable chain 3. Fly duct 4. Swiveling tower 5. Control box 6. Take off unit 7. Suction duct 8. Traversing rails 9. Bale lay down area Chassis Cleaning Machine: Cleaner machine is an important machine in spinning for opening and cleaning impurities from cotton. This machine is set normally after Bale Opener machine. Double pin beater 2. Grid bar 3. Mixing is done after the study of the essential properties of fiber like staple length, tensile strength, fineness, uniformity etc.
Fibers actually stored in six chambers and mixed up by beating. Storage Section 9. Material exit 2. Separating Vanes Stripper roller 3. Conveyor Belt Take-off roller 4.
Top exhaust air exit Spiked feed lattice 5. Partitions Opening and cleaning unit 6. Downwards exhaust air Waste chamber 7. Intermediate section Conveyor belt drive 8. In this section fine cleaning is done through beating and waste products are separated. Mechanical action on fibers causes some deterioration on yarn quality, particularly in terms of neaps. Figure: Fine cleaning or uniflex machine and identification of their major parts From figure above the major part of fine cleaner machine: 1.
Inlet duct 7. Feed roll 2. Ventilator 8. Trough 3. Dust cage 9. Grid bar 4. Plain drum Waste box 5. Cleaned cotton outlet duct Laminar chute 6. The most effective protection here consists of two stages: One for the separation of metals, heavy parts and burning material at the start of the cleaner line and one for the specific separation of foreign parts foreign fibers at the end of the cleaning line. This chute material sends to the carding machine for further processing via chute line.
Figure: Rieter condenser unit in blow room From figure above, the major parts of a condenser are: 1. Material feed 7. Fan 2. Feed funnel 8. Guide plate over take-off roller 3. Perforated drum 9. Protected cover Switch 5. Exhaust air outlet Material delivery 6. Mainly impurities are removed at the intake and the naps and short fibers are removed by action between the cylinder and flat.
It is called the heart of cotton spinning because the quality of a yarn is greatly dependent upon the carding machine. In carding machine, cotton converted into sliver, which is deposited in sliver can.
Figure: Carding machine and its major parts. From the figure above, the major parts of a carding machine are: 1. Aero feed 8. Carding profile Waste removal 2. Material distribution device 9.
Detaching device 3. Fleece pick-up by cross apron 4. Flat cleaner Stepped rollers 5. Flat Doffer 6. Cylinder Bottom part of the machine 7. Complete covering Also fiber blending can be done at this stage. Some other tasks of this draw frame are drafting, parallelizing, blending, dust removal etc.
Usually, it takes 12 sliver can as input and give one sliver can as output. Breaker Drawing and Finisher Drawing looks similer but the main difference between these two is Finisher Drawing has Auloleveller. The escape wheel I26, which is connected to a lever escapement mechanism of form of device for use in accordance with the present invention.
In this modification, in place of the stud and roller mechanism of Figures 6 and 7, a pair of bars I00 and I02, each containing a plurality of pegs, is used.
The bars I00 and I02 are positioned at an angle to -the axis of the bobbin so that the yarn will have a tendency to slide along the bars and drop from the outwardly projecting ends thereof. The bars must also be spaced from the automatic pick-up traverse guide 00 to prevent contact of the guide with the yarn until after the waste yarn and traverse tail have been wound. The bar I00 is made stationary while bar I02 is connected to a periodically reciprocating mechanism not shown The bar I02 must be reciprocated from a position, sufficiently below bar I00 that pegs Al, A2, A3 A9 will not contact the yarn, to a position sufiiciently above bar I00 that pegs Bl, B2, B3 B0 will not contact the yarn.
In stringing the yarn to the emptybobbin 20, the yarn is first passed over bars I00 and I Bar I02, being in its uppermost position, the yarn will slide to the right as viewed in the drawing until it contacts peg AI. Upon lowering bar I02 to its lowermost position as shown in dotted lines in Figure 9, the yarn will slide to the right until it contacts peg B2 of bar I Upon raising bar I02 again, the yarn slides to peg A Upon each successive raising and lowering of bar I02, the yarn alternately slides into contact with pegs B3, A3, B4, A4 etc.
The yarn 32 is picked up by the traverse guide Since the bars project beyond that section of the bobbin on which the yarn cake will subsequently be wound, seeFlgure 8 a plurality of yarn windings I04 will be laid on the bobbin beyond the yarn cake. The outermost winding I04 may be cut at one end and the yarn end used as a transfer tail. The length of yarn to be discarded as waste will be determined by the speed of reciprocation of bar I02, the number of pegs on the bars, and the speed of winding.
Referring toFigures 10 and 11, another device islllustrated whichv may be substituted for the stud and roller mechanism shown in Figures 6 and 7. One end of bent arm I20 is provided with a hook Iand an escape wheel I26 of a lever escapement is fixed on the other end. The bent bar may conveniently be positioned on one side. The bent bar is brought around to the position shown in full lines in Figure The yarn is then strung on to the empty bobbin and looped over hook I24 of bar.
The position of hook I24 at the point where the yarn slides therefrom must overlie a section of the bobbin beyond that on which the yarn cake will be formed so as to lay a plurality of windings I28 on the bobbin which will project from the yarn cake. The outermost winding I28 may be cut and used as a transfer tail. The length of yarn to be discarded as waste will be determined by the number of teeth on the escapement wheel, the tension of the yarn, and the The conventional lever escapement mechanism shown in Figure 12 is illustrative of one form of mechanism suitable for use in controlling the rotation of bar I Obviously, other known means can be employed in place of the escapement mechanism to control the rotation of bar I On the other hand, the bar l20 may be connected, for example by gearing, to a motor and thus be operated in a positive manner by an external mechanical force rather than by the movement of the yarn and the tension imparted thereby.
Such a method is very desirable in a case where the yarn being wound upon the bobbin is not strong enough to cause the bar to move against the action of the escapement means or other controlling mechanism. By the practice of the present invention, it is possible to wind a predetermined length of inferior yarn on a bobbin, which length will automatically be discarded as waste in a subsequent continuous unwinding of the yarn from a plurality of yarn cakes.
Nearly all of the waste yarn will be wound under the yarn cake and will be purified during the regular purification operations and, therefore, willnot later contaminate the yarn in the cake. By use of this invention it is unnecessary to rewind yarn in order to discard inferior or improperly purified yarn.
Numerous modifications for accomplishing this essential series of winding steps are described and illustrated above. Obviously, the present disclosure will enable others to make many changes and modifications in the above-disclosed devices without departing from the nature and spirit of the present invention. It is, therefore, to be understood that the invention is not to be limited to the details above-described except as set forth in the appended claims.
The method of winding a continuous yarn on a supporting element for the production of a yarn cake which comprises winding a length of said yarn on that section of a yarn supporting element on which the wound cake is subsequentlyto be wound, then winding a length of said yarn on that section of the yarn supporting element which is to project beyond said wound cake, and v then continuing thewindingof the yarn on said first-named section of said supporting element to form said cake.
The method of winding a. In an apparatus for winding a continuous yarn for the production of a yarn cake, in combination with a rotating yarn supporting element, means for guiding a lengthof said yarn on to that section of said element on which the yarn cake is subsequently to be wound, means for guiding a subsequent length of said yarn on to another section of said element, and means for guiding a continuing portion of said yarn on to said first-named section of said element for the formation of said yarn cake.
All of these appear to be related in some way to yarn laydown at the reversals, i. Heretofore, means have been devised to improve yarn distribution at and near the package ends, such as by superimposing an axial reciprocation on the primary traverse stroke or by changing the length of the stroke cyclically by mechanical means with essentially no change in yarn helix angle to spread out or disperse the yarn laydown at the package ends or shoulders.
These and other approaches provide very limited dispersion pattern or because of mechanical limitations are not applicable to high-winding speeds. It is also a common practice in crosswinding to vary traverse speeds in a regular cycled fashion between a positive value and a negative value about a predetermined traversal rate for the purpose of preventing ribbons, which are a buildup of superimposed yarn windings laid approximately one on top of the other.
These speed fluctuations however are relatively small and have little effect on the yarn laydown pattern at the reversals. It is known that increases in traverse rate, that is, winding at larger helix angles may be used to reduce package bulge and move the yarn reversals on the package inward. However, the use of high-helix angles per se is restricted by the problem of overthrown ends.
It is also known that overthrown ends can be reduced by slower, more stable reversals at the end of the traverse stroke, but this leads to excessively high and hard shoulders on the package.
No completely satisfactory balance of conditions for high-speed winding exists with the currently known winding concepts. Another object of this invention is to provide a yarn-winding process adapted to produce large yarn packages with improved stability in handling and shipping. Another object is to provide a method of controlling yarn tensions in winding. A further object is to provide improved packages of yarn wound under high tension.
A further object is to provide yarn packages with low variations in surface hardness. These and other desirable objectives are accomplished in a process for winding yarn into a cylindrical-bodied substantially straight-ended yarn package wherein the yarn is forwarded at an essentially constant thread line speed and is wound on a bobbin in layers of helical coils at a substantially constant helix angle to form the package.
During winding, the package is rotated at a substantially constant peripheral rate of speed while the yarn is traversed back and forth axially across the package at a substantially constant traversal rate. According to the invention, the improvement comprises increasing the traversal rate in spaced repeating periods throughout the winding of the package. The linear speed of traversing is regulated in a predetermined pattern over shortspaced repeating periods greater than the period of one traverse cycle such that the helix angle is held substantially constant then is varied cyclically to a helix angle significantly larger than the maximum helix angle attained during the period of winding at substantially constant helix angle.
Tension fluctuations in the winding yarn caused by cyclically varying the helix angle may be compensated for by varying the peripheral package winding speed coincident with and in an inverse relationship with respect to the traverse speed. According to another aspect, the invention comprises a cylindrical-bodied substantially straight-ended yarn package wound on a bobbin in layers of helical coils characterized by the helix angle of the coils in the package being varied in spaced repeating periods throughout the package from a minimum value to a maximum value and back to the minimum value in each period.
The helix angle of the coils is varied cyclically in spaced periods throughout the package from a base helix angle through a range of helix angles such that the maximum helix angle is substantially larger than the maximum positive helix angle in the intervening base periods, and the point at which the yarn reverses direction at or near the end of the package in a helical coil is displaced axially inward from the end of the package in direct relationship to the helix angle in that helical coil.
In the subject method of winding a yarn into a package the yarn laydown at the reversal points is dispersed inward away from the package ends during the period of changing helix or excursion because, with no change being made in the actual length of the transverse stroke, the effective stroke length is reduced when yarn at essentially constant thread line speed is laid down at higher helix angles and then increased when yarn is again laid down at lower helix angles. Using the variablehelix winding method of the invention, overthrown ends are not obtained at the higher helix angles because the package ends or walls are defined by the yarn laid down during the period of low-helix traversing.
The minimum or base angle in the helix angle cycle is generally selected to be at or near the optimum angle which would be selected for good winding at essentially constant helix angle with particular regard to minimizing overthrown ends.
Higher maximum helix angles can be tolerated and thus higher average helix angles can be obtained because winding at the minimum or base angle establishes the package walls. I it will be seen that the windup chosen for purposes of illustration generally includes, as components thereof, a traverse cam 20, a surface drive roll 14, swing arm 28 mounted for relative rotation about pivot 30 and rotatably supporting bobbin 16, a reciprocating traverse guide 12 through which yarn from a source not shown advances from guide 11 under drive roll 14 to a package 18 on bobbin Suitable means such as motors 22, 24 along with belts 26, 26 are used to drive traverse cam and drive roll 14 respectively.
Motors 22, 24 are synchronous motors and their speeds are individually controlled by solid-state power supplies 32, 34 connected to the motors through leads 36, These power supplies vary motor speed by varying the frequency of the voltage supplied to the motors. A function generator 40 is connected to power supplies 32, 34 through leads 42, 44 respectively.
Referring now to FIG. Amplifier 56 amplifies signal 55 to form signal 55 which is fed over lead 42 to solid-state power supply Inverter 58 inverts signal 55 to form signal 59 which is then amplified as desired in amplifier 60 to signal 59' that is fed over lead 44 to solid-state power supply Signals 55 and 59' serve to modify the output voltage frequency of power supplies 32, 34 and the rotational speeds of motors 22, 24 are changed accordingly.
The resultant speed changes vary the traversing rate and consequently the package helix angle and the peripheral package speed in a predetermined pattern in accordance with the output of function generator The yarn package 18 is driven at a peripheral speed, varied in accordance with the inverted output signal 59', by contact with drive roll 14 which acts also as a print roll in forwarding to the package 18 the yarn laid down from traverse guide As yarn builds on package 18, spring-loaded pivot arm 28 is urged away from the surface of roll 14 to permit the increase in package diameter.
Throughout the course of winding the helix angle at which the yarn is laid on the package 18 is varied cyclically by controlling the rate of the traverse guide The throw of the traverse guide, i. The length of the yarn laydown pattern is afi'ected by changing the angle at which the yarn is laid down.
It will also be realized that, the extent of change in length of the pattern on the yarn package will depend on part on yarn friction and retraction properties, and on roll surface friction. The change in laydown length 37 vs. Other winding parameters being held constant, the laydown pattern is shortest at the larger helix angle 33 and longest at the smallest helix angle This means that the package ends 19 are defined as the yarn is wound at lowest helix angle 31 in the helix angle cycle.
The helix angle cycle is the cycle of helix angle vs. Helix angles will be understood to be the angles measured at the package surface between the yarn coils 21, 25 and a plane perpendicular to the package axis away from the package end As shown schematically in FIG.
This area will be called the package shoulder. The reversal 21a of coil 21 at lowest helix angle defines the package end 19 The reversal 23a of coil 23 wound at a higher helix angle is displaced inward slightly toward the center of the package and the reversal 25a of coil 25 wound at the maximum helix angle is displaced inward a maximum distance indicated by dotted line 35'.
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