A yarn tension control device and a process for use in winding an intake yarn onto a revolving bobbin core

Abstract

The invention discloses a device and process of controlling / stabilizing tension in a filament / monofilament, flat / fibrillated tape or yarn while winding it on a core in a winding machine. More particularly, it discloses a multistage tension control device to precisely control the tension in winding of low denier yams as low as up to 15 denier or so. The initial stage of the device has a stabilization roller unit (1) and the last stage comprises a moving arm mechanism (7). The stabilization roller unit (1) comprises a yarn aligner support (4), a positively driven accumulator roller (3), a stabilization roller (2). The moving arm mechanism comprises a moving guide wheel (8), a moving arm (9), a pivot pin (14), a moving arm stopper (12), an exit guide wheel (10), a low friction cylinder (16), and a balance weight (15). The device and the process of invention improves the bobbin quality.

Description

[0001] A YARN TENSION CONTROL DEVICE AND A PROCESS FOR USE IN WINDING AN INTAKE YARN ONTO A REVOLVING BOBBIN CORE

[0002] Field of Invention

[0003] The invention relates to a winding machine that is intended for winding a yarn made up of any winding material with different cross-section, particularly a filament / monofilament, flat / fibrillated tape or any similar type of yarn onto a revolving bobbin core. Furthermore, the invention relates to a multistage tension control device to precisely control the tension wherever required, i.e., including but not limited to winding of low denier yarns as low as up to 15 denier or so. In context of the invention, the multistage tension control device comprises a stabilization roller unit in first stage(s) of tension control and a moving arm mechanism in the second stage for precise tension control. The invention further aims to improve the bobbin quality, reducing line breakage and ensuring precise and consistent tension control during winding the yarn of both nature, continuous advancing as well as by pulling the yarn from the bobbin or the plurality of the bobbins.

[0004] Background of Invention

[0005] In the following description, the term "yarn" is intended to include threads, tapes, profile tapes, fibrillated tapes and slit-film bands of various linear mass densities, diameters, widths, and thicknesses.

[0006] The term " core" is intended to include any metallic or non-metallic tubes on which the yarn is wound to form a suitable package, called “bobbin”.

[0007] The term “winding” indicates a process of laying the yarn onto a revolving core in a layer-by-layer pattern in a controlled manner, ensuring even distribution of yarn that is suitable for easy unwinding in successive stage. The term “yam source” is defined as the origin of the yarn that is coming to the winding machine for making bobbins. The source could be of many types. It could be an online yarn source which comes from an extrusion machine where the yarn is getting produced continuously and advanced to the winding machine for getting wound over the core to form bobbins. It could also be by pulling the yarn or bunch of yams from one or plurality of bobbins, and then getting rewound on the winding machine with some value addition in the process, in the form of bobbin, this is called an offline yam source. Here, value addition refers as, winding more than one yarn of similar or different kind or color to form a bobbin, undergoing yam dying and curing process before reaching winding machine, undergoing oiling process thereby intermingling the yarn during winding, such processes are generated or performed as per requirement of person skilled in art.

[0008] The term “Denier” is a unit used for filament yam (continuous long fiber) and represents a measure of linear mass density of fiber and refers to the weight (in gram) per 9000 meters. Lower the denier number, the thinner the yam. The textile industry has various units in use intended to measure the linear mass density of fiber. Most widely used units in the textile industry in the context of yam are den (denier), tex and dtex (deci-tex).

[0009] The term “Winding heads” indicates the number of winding locations, stacked horizontally and vertically in a winding machine used for winding the incoming yarn onto a revolving core.

[0010] The term “Yam characteristics” defines the quality of yam; it includes strength, fiber content, count, volume, hairiness, evenness, appearance, etc.

[0011] The term “winding machine” indicates a plurality of winding heads arranged in vertical columns and horizontal rows which may further configured in multiple lines. The travel distance of the yam from the yam source to the winding head varies significantly. Winding machines could be of various types depending upon the type of doffing, drive system, characteristics of yam to be processed, etc.

[0012] As the length of the yam path varies from the yarn source to the winding heads, different amount of slag, snarling and swaying occurs in the yam which affects the winding tension differently resulting in the bobbins of unacceptably variable quality. The effects vary between winding heads and are more profound as the distance variation increases. The yarn in the winding machine typically travels over several supporting elements before reaching the winding head, thus greatly reducing the above said issues but simultaneously creates undesired frictional contact points due to rubbing and dragging along the path. This can be a detrimental factor for bobbin quality, especially in the case of any sensitive yarn such as low denier yam.

[0013] When winding low denier / thin / sensitive yam, say 15den, long distance factors, and friction factors come into the play which greatly affect the set winding tension which in turn affects yarn characteristics like strength, elongation, hairiness etc., ultimately resulting in poor bobbin quality, line breakage issues and production efficiency loss. Furthermore, low denier yam also demands low and precise tension setting for good quality bobbin. The tension in the system for the winding material of certain denier should be maintained. Even a moving rod self-weight and internal friction between tension controlling parts can adversely affect the characteristics of the bobbin quality in case of low denier yam which is not the case if the denier is not very low. Even a slight variation in quality of the bobbins thus produced affects the price of bobbin in domestic and international markets. Therefore, it is necessary to produce bobbins of best possible quality.

[0014] The object of the invention is to provide a novel device (or system) for precisely controlling the low denier / fine yarn tension and preserving the yarn characteristics throughout the winding process, thus ensuring consistent bobbin quality.

[0015] In prior art known to the applicant, CN221680304U clearly mentions the importance of tension control to achieve good, coiled material product. It only mentions suitability for winding flat cables, not suitability for textile yams including low denier yarn. It is a single stage tension control system which doesn’t include any secondary stabilizers to handle the tension variation issues on multiple winding heads.

[0016] The prior art document JP07053128A deals with unwinding of yam from a bobbin and is not related to the winding process. Also, the speed control technology disclosed in this document is relatively primitive and depends on the load slip and break mechanism, which is not precise, its coarse control as compared to electronic counter parts. Further, the said device is not suitable for thin / low denier yarn as it required precise tension control.

[0017] The prior art document US10538409 B, discloses a winding machine with swinging arm as only a tension control method with the control range that is not much suitable for low denier yarn as it only has a single stage tension control device which is not enough to manage the precise tension control required for thin / low denier yarn. Further, the said system in this prior art is prone to tension variation between the winding heads depending upon the large variation in yarn travel distance which is again not suitable for thin / low denier yams as this will greatly affect the bobbin quality.

[0018] The prior art document CN119038321 A discloses a single stage yam tension control device of turn table type only suitable for offline process, also this device is not suitable for precise tension control, thus not suitable for low denier / thin yarn. The prior art document CN204342107U discloses a single stage tension control device that comprises crossed passing rollers positioned before and after the swinging arm, the swinging arm, a floating roller on the swinging arm and a control system. The passing rollers are positively driven whereas in our case the rollers are not crossing roller type, and they are mounted on rolling bearing. This system is specifically for processing flat tapes without twisting (e.g., carbon fibre) and not suitable for low denier filament yams.

[0019] Thus, there is need of a device (or system) which can provide precise and adequate yam tension for winding excellent quality bobbins. Further, a system is required for handling excellent quality bobbins with high production efficiency in manufacturing process, more specifically the critical ones, e.g., low denier yarn.

[0020] Objects of Invention

[0021] An object of the present invention is to provide a device for administering precise and adequate yam tension for winding good bobbins.

[0022] Another object of the present invention is to provide a multistage tension control device that comprises a stabilization roller unit in the first stage(s) and a moving arm mechanism in the second stage of tension control.

[0023] It is a further objective of the present invention to stabilize all variations and fluctuations of the yam tension in first stage(s) and then feed the yarn to the revolving core through a second stage which is moving arm mechanism that is further intended to deliver precise and adequate winding tension to the yam

[0024] Another objective of the present invention is to precisely maintain the winding tension across all winding heads of a winding machine irrespective of its position.

[0025] The further objective of the present invention is to provide precise and adequate winding tension for critical applications, e.g. applications involving yarns of as low as 15 denier or so.

[0026] The further objective of the present invention is to wind good quality bobbins with high production efficiency in manufacturing process, more specifically the critical ones, e.g. low denier yarn.

[0027] Other objects of the present invention will be clear from the ensuing description of the invention.

[0028] Brief Description of Figures

[0029] Figure 1 shows a schematic of the present invention consisting of first stage which is stabilization stage consist of stabilization roller unit and a second stage which is moving arm mechanism.

[0030] Figure 2 shows another view of the present invention, showing the yarn path over the stabilization roller onto the moving arm mechanism.

[0031] Figure 3 Shows the multistage control device assembled on a winding head and showing the yam travel path up to the revolving core forming a suitable package.

[0032] Figure 4 shows multiple winding heads on a winding machine with the control device on each head.

[0033] Figure 5 shows a multistage tension control device on a winding machine with three stage of tension control, consisting of two stages of stabilization roller unit to provide the first pre-stabilization to the yam, then pre- stabilized yarn further stabilized in stabilization roller unit.

[0034] List of Parts

[0035] 1. Stabilization roller unit

[0036] 2. Stabilization roller 5. Intake yam

[0037] 3. Accumulator roller 6. Accumulator roller drive motor

[0038] Yam aligner support 7. Moving arm mechanism 8. Moving guide wheel 16. Low friction pneumatic

[0039] 9. Moving arm 10 cylinder

[0040] 10. Exit guide wheel 17. Revolving core

[0041] 11. Exit yarn 18. Bobbin (developed package) 12. Moving arm stopper 19. Main plate

[0042] 13. Sensing Device 20. Support element

[0043] 14. Pivot pin 15 21. Winding machine

[0044] 15. Balance weight

[0045] Summary of Invention

[0046] The invention describes a novel multistage tension stabilization and control device (or a system) (Fig. 1) that facilitates precise and adequate tension on bobbin (18) even for the low denier / thin / sensitive yams during the yam winding process. The multistage tension control device (Fig. 1) of the invention is explained using the example of two stages in which the tension in the yam is controlled: the first stage being a stabilization roller unit (1) and the second stage being a moving arm mechanism (7).

[0047] The device may have multiple stages on yam tension control where the last stage will always be the moving arm mechanism (7), and all prior stages would be individual stabilization roller units (1) arranged in a series.

[0048] The novel multistage tension stabilization and control device (Fig. 1) is mounted on a main plate (19) of a winding head (Fig. 3). The stabilization roller unit (1) comprises a yam aligner support (4), a positively driven accumulator roller (3), accumulator roller drive motor (6) and stabilization roller (2) that is suitably inclined at some adjustable angle to provide uniform gap between the wrapped yarns. The angle of the stabilization roller being the angle of the central axis of the stabilization roller has with the angle of the central axis of the accumulation roller (3). Further, the stabilization roller (2) can be adjustable to control the swaying motion and maintain the required gap to prevent the yam from tangling / rubbing to each other, as it will affect the tension values and yam characteristics. Inclination helps in separating the yarn and adjustability of inclination helps maintaining the uniform gap and in controlling swaying motion. The moving arm mechanism (7) comprises a moving arm (9), a moving guide wheel (8) mounted on the moving arm (9), a balance weight (15), a moving arm stopper (12), a rotation sensing device (13), a low friction pneumatic cylinder (16) and an exit guide wheel (10). The yarn tension stabilization and control device (Fig. 1) is mounted on the main plate (19) of a winding head (Fig. 3) of a standard yam winding machine (21). All the components of the multistage tension stabilization and control unit are arranged in the specified order to precisely provide adequate winding tension to the yarn to form a good quality bobbin (18). The components are arranged along the yarn path in an order to first perform the yarn stabilization in the first stage of tension control and then to further precisely control the tension of the stabilized yarn in second stage of tension control.

[0049] Adequate winding tension is used in winding machinery terms to define the quality of the bobbin when unwounded. In-adequate tension in bobbin will result in improper unwinding, line breakage during un-winding or even not possible to unwind depends upon the level of variation.

[0050] The present technology in the market is inadequate to achieve consistent bobbin quality when winding low denier / thin yarn on multiple winding heads. Here the consistency means, producing similar quality of bobbin on multiple heads repeatedly. When multistage tension control is not there and winding of low den yarn performed on the winding machine, the quality of the bobbin differs even on the immediate successive heads, here quality means bobbin has even spacing between the yarn, smooth side and top faces, moderately tight package, Inconsistent winding are prone to yam breakage during un-winding. The said invention aims to provide a novel solution to achieve a precise control on the tension value of low denier / thin / sensitive yam and to provide a consistent bobbin quality. The said invention eliminates the effect of tension variation due to long yarn path up to the winding heads; frictional effect of contact support elements (20) by providing multistage tension compensation system.

[0051] When there are multiple operating winding heads, the yam from source has to travel more to reach the last head than the first head. Along the travel path, the yarn is supported on contacts of support elements (20) so that it doesn’t sway or hinder the other yarn’s path. There may be multiple support elements (20) depending on how far the winding head is from the yam source. The support elements (20) themselves have some friction which affects the yarn, and which varies between the heads. The present invention has two-stage (but not limited to two stages only) tension control, the first stage being the stabilization roller unit (1) comprising the yam aligner support (4), the stabilizing roller (2) which is driven by a motor (6), and the accumulator roller (3). The intake yarn (5) first reaches the yam aligner support (5) which aligns the yarn for the accumulator roller (3), following which the yam gets wrapped several times over the accumulator (3) and stabilization roller (2). The number wraps the yam undergoes depends on the denier and tension required. As the yarn moves over both rollers, any tension variation in the line results in horizontal swaying of the yam over the rollers. Further, because of swaying motion, there is variation in the gap between the wrapped yam. By adjusting the stabilization roller (2) angle, the yarn motion gets stabilized, which in turn the controls the tension in the line up to the winding head. The stabilized yarn is then fed to the second stage of tension control which is moving arm mechanism (7). Due to tension control in first stage, the yarn that enters the second stage will have the same tension value on all winding heads. Also providing first stage of tension control helps preserving yarn characteristics, thereby adding to the bobbin (18) quality. The following example illustrates the method by which the present invention works. A UHMDPE (Ultra high molecular density PE) yarn of 15 denier was used from the offline source to be wound on a revolving core (17). The source line speed is set at 150mpm (meter per minute), the tension for winding is set to 25cN, the yarn is wrapped five turns onto the stabilization roller unit. The accumulator roller (3) speed is set at lOOOrpm, matching with line speed. The electro-pneumatic control system set for the range 22.5cN to 27.5cN. During winding, the tension of the yarn is measured using precision tension meter after the stabilization roller unit, the measured tension variation is within range “-6.3% to 6.9%” of set value, the tension after moving arm mechanism was tested, the measured variation turns out in between the range “-4.8% to 5.1%” of the set value which is promising results.

[0052] The moving arm mechanism consists of a moving guide wheel (8) mounted on the moving arm (9) which is on the pivot pin (14) mounted on the main plate (19), the moving arm (9) is supported by either a spring drive or pneumatic cylinder (16) to provide spring action pressure on the yam path during winding. The spring action applies pressure on the yam path that is over the guide wheel (8) to maintain the adequate tension in the yam path.

[0053] The spring action on moving arm can be of fixed nature if spring drive is used and can be of variable nature if the pneumatic cylinder drive is used which is controlled by electro-pneumatic system.

[0054] When yam drags over the moving guide wheel (8), the set tension required is provided by the moving guide wheel (8) by applying adequate pressure on the yarn path with the help of either spring drive or pneumatic drive. The yarn from the moving guide wheel (8) goes to exit guide wheel (10). This exit yam (11) then gets fed to the traverse mechanism (22) and then onto the revolving core to form a bobbin. The moving arm mechanism (7) could be positioned horizontally, vertically or in any other suitable position for the application, could be design with and without balance weight (15)) which can be adjustable or fixed in nature, the adjustability can also be controlled manually or electronically. Balance weight (15) is required to nullify the weight of the moving arm and the guide wheel about the pivot pin for low denier / thin / sensitive yams. Adjustability required to adjust the weight to reach that position, it is done before start of the winding.

[0055] The moving arm (9) is made up of light weight advance material such as hollow spring steel, composite material and other advance material suitable for low denier application.

[0056] When spring drive is used in the system, it is only limited to a fixed nature of control as per the designed spring rate. When using more advanced electropneumatic systems which use low friction cylinder drive, variable spring rate can be achieved which is more helpful for precise control of tension. The moving guide wheel (8) also made up of light weight advance material such as aluminum alloys, magnesium alloys or other suitable material for low denier / critical tension control application.

[0057] Detail Description of Invention with reference to drawings

[0058] Fig. 4 shows a typical yarn winding machine (21) where plurality of winding heads as shown in Figure 3 are arranged in vertical columns and horizontal rows. The novel multistage tension stabilization and control device as shown in Figures 1 and 2, is mounted on the main plate (19) of a typical winding head (Fig. 3). It also comprises of a revolving core (17) and a traverse mechanism (22).

[0059] Intake yarn (5) from the source (online or offline) get dragged over the support elements (20) which can be fixed or rotatable in nature and can be of different metallurgical property with different friction coefficient. Intake yarn (5) then passes from the yarn aligner support (4) which guides the yarn onto the yam accumulator roller (3) and stabilization roller (2). Fixed support used when there is large tension variation in the line, yam has tendency to jump out from the support or yam count is more, generally placed at the start point on the winding machine. Moving guide roller generally used between the heads or when there is abrupt change in yam direction, to support the yam within the machine. Friction coefficient depends on the nature of contact, in case of fixed support where slipping is required, low friction coefficient needed, in case of rotatable support, friction coefficient is higher than the fixed to reduce slippage over it times.

[0060] The intake yam (5) gets wrapped several time over the accumulator (3) and stabilization (2) rollers as shown in Fig. 2, where the number of wraps depends on denier and tension values required for yam. Accumulator roller (3) is motor (6) driven with speed control to maintain the desired winding speed depending upon the nature of application and the yam source.

[0061] Depending upon the need of the application, pretension or relaxation in yam can also be achieved from the accumulator roller. For example, when winding from offline source, pre-tension in the yam required which is provided using accumulator roller, whereas during winding from online source, relaxation in yam is done.

[0062] The stabilization roller (2) is adjustable in angular direction and mounted at an inclined angle with the accumulator roller (3) to provide uniform gap between the wrapped yarn such that when the yarn gets wrapped on the stabilization roller (2) and accumulator roller (3), the gap should be uniform. If tension is adequate, If there is non-uniformity in gap and yarn sway over the rollers, the stabilization roller (2) can be adjusted to achieve the uniform gap thus controlling the horizontal swaying motion in the yarn results from tension variation in the line. Variation in the yarn speed and tension variation up to the head can be stabilized in this stage, and which can be verified using a tension meter. The tension variation checked after stabilization roller unit (1) for 15 den UHMDPE (Ultra high molecular density PE) yam the variation is controlled within ±7%.

[0063] The adjustability can be achieved manually or electronically, by adjusting the angle of stabilization roller (2), a stable point will be achieved where the gaps in between the yarn will become even and the sway motion get controlled, this stabilized the yarn. The stabilization roller unit (1) absorbs the tension variations up to the winding heads in first stage of tension control thereby stabilizing the yarn tension. The stabilized yam is then fed to traverse mechanism (22) than onto the revolving core (17) through the moving arm mechanism (7) of the second stage of tension control that is designed to deliver adequate winding tension to the yarn.

[0064] The moving arm mechanism (7) arrangement is offered in different configurations including but not limited to the following

[0065] - positioned horizontally, vertically or in any other angular position suitable for the application;

[0066] - designed with or without the balance weight (15), that is adjustable or fixed in nature; or

[0067] - designed to deliver spring or pneumatic force of fixed or variable nature to the yam getting wound on the spindle

[0068] Position of the arm depends on the designed yarn path, bobbin diameter required, number of winding heads needed to be arranged and compactness in the design of the machine.

[0069] Purpose of the moving arm mechanism (7) is to provide constant tension to the yarn path through moving arm and guide wheel by applying pressure on the yarn path by the spring action motion. This is done using moving guide wheel (8) over which yam moves, the moving arm (9) is supported by either a spring drive or a low friction pneumatic cylinder (16). With the spring, the tension is limited which is fixed in nature as per the spring rate, with the pneumatic cylinder (16) which is controlled by electro- pneumatic system, the spring rate is adjustable.

[0070] Any one or the combination of the moving arm mechanism types are used to ensure adequate winding tension in the second stage of our innovation.

[0071] In the present invention shown in fig. 1, the moving arm (9) moves around the pivot pin (14) and precisely delivers required tension by applying pressure on the yarn path through moving guide wheel (8) with the help of special low friction pneumatic cylinder (16). The air pressure can be adjusted and controlled precisely with the help of electro-pneumatic means. The arm movement is further constrained within moving arm stopper (12) Stopper (12) required to prevent the arm control system to touch there extreme ends or travel further preventing any damage to control system in the prolong use. For example: low friction pneumatic cylinder (16) is a delicate component, with the moving arm stopper (12), the internals of the cylinder will not touch the extreme ends thus preventing any damage in the prolong use.

[0072] During winding on the revolving core (17) as the layer of the wounded yarn increases, this increases the diameter of the wounded yarn on revolving core (17), the increase in diameter pulls the yarn with speed more than the set surface speed, The following example will illustrate shown in Fig.3, ‘v’ is the surface speed of the upper layer of wounded yam, ‘r’ is the half diameter of the wounded yam, ‘co’ angular speed of revolving core (17), for any instant, using a simple formula ‘v=r*co’ as ‘r’ increases, if ‘co’ remain the same at that instant, surface speed ‘v’ will increase with increase in diameter, this pull in the yam with the higher speed than an instant before. As the yarn is moving at a certain line speed ‘u’, the abrupt speed change will result in the tension increase in the yam path. This increase in tension in yarn path, results in the shift of the moving arm (9). The shift in position and angle ‘0’ of shift of moving arm (9) is sensed by the sensing device (13) which signals the central control unit to increase the angular speed ‘co’ of the revolving core (17) as per the angle ‘0’ of shift of the moving arm (9) to maintain the constant surface speed ‘v’, simultaneously maintaining the constant tension throughout the winding process.

[0073] The angular shift in moving arm (9) is detected by the sensing device (13), shift happens when there is tension variation in the yarn path. The sensing device (13) sends the signal to the control unit about the angle ‘0’ of shift. Depending upon the angle ‘0’ of the arm movement, the control unit modulates the revolving core (17) speed to maintain the surface speed constant, which makes the yarn to again shift the moving arm in opposite direction. The pneumatic cylinder (16) is connected to the moving arm (9). The pressure within the cylinder is controlled by electro-pneumatic system which work against the yam force to precisely regain the arm position without jerk or overshoot.

[0074] As the speed varies to maintain constant surface speed ‘v’, the tension in the yarn varies again, it moves the arm back to regain its position which can be with jerk or likely overshoot the set position if the arm is without any control. In such situations, the cylinder attached to the swing arm provides the support required with electro-pneumatic system, which works against the yarn force to precisely regain the arm position without any jerk or overshoot. The device is designed to control even a micro level angular shift in arm position instantaneously to maintain constant yam tension and surface speed ‘v’. The yarn from the movable guide wheel (8) is guided over the exit guide wheel (10) onto the winding core (17) to form a bobbin (18).

[0075] The multistage tension stabilization and control device as described in the present invention is capable of winding good quality bobbins (18) with high production efficiency in manufacturing process, more specifically for the yarns, of denier as low as 15 or so. The following example illustration will explain the importance of this device. In a typical winding machine (21), the tension control will generally be within ±10% tolerance variation of the set value to wound a good bobbin (18). Let’s say if you wound a yarn which required lOOcN, if you check the control range it will be within 90 -1 lOcN which can be easily controlled but when you go for yarn which required 15cN typically low den yarn, the control range will be limited to 13.5-16.5cN which is tight range to control with the existing system as a simple slag in yarn path or drag results from the yarn support, the manufacturability of assembled parts can create deviation from the range. For this we need a device to precisely maintain the tension for such a tight range of control. Our novel invention provide a device with multistage tension control to manage and control these variations precisely, to always maintain the tension within the control range.

[0076] As stated earlier, the invention has been explained using a two-stage scenario. Here, the low denier yarn reaches the winding machine from an online source. At winding machine, the variation in yarn tension due to yam travel path is stabilized in a stabilization roller unit and then the stabilized yarn with almost no tension variation reaches the second stage that is a moving arm mechanism which is designed to deliver adequate winding tension to the yarn.

[0077] In another scenario, especially where the stabilisation achieved in the stabilisation roller unit is not adequate, a three stage (or more) device is used. Here, the low denier yarn reaches the winding machine from an offline source. At the winding machine, a stabilization roller unit drags and stabilizes the yarn. If the stabilization achieved by the first stabilisation roller unit is not adequate, another stabilisation roller unit is introduced before the first stabilization roller unit, called as pre stabilization roller unit. The yarn will then go to stabilization roller unit and the fully stabilized yarn then reaches the moving arm mechanism.

[0078] This device reduces the line breakage during operation of low denier yarn, and maintains consistent bobbin quality. In online process a single line breakage can result into subsequent loss of the material, as production line of yam cannot be stopped. The bobbin which was in the winding stage will get rejected due to incomplete in nature, the time and manpower also get wasted in re threading the same. The loose yam may also interfere with other winding heads which will result in multiple breakdowns.

[0079] Further the process of multistage tension control to get a stabilized yarn with adequate tension to be wound on the revolving core is listed below.

[0080] A. Passing the intake yarn (5) from of a source over the support elements (20) on the winding machine (21) to get wound of revolving core (17) of the winding head (19).

[0081] B. Thereby feeding the said intake yarn from support elements to the first stage of the tension control i.e. yarn stabilization roller unit (1).

[0082] C. Next said intake yarn (5) enters the yarn aligner support (4) of the stabilization roller unit (1) thereby aligning the yarn for the accumulator roller (3), making starting point of the yarn on accumulator roller (3) same for all winding heads.

[0083] D. Further wrapping the intake yarn several times on the accumulator roller (3) and stabilization roller (3)

[0084] E. The accumulator roller (3) is driven by motor (6) with speed control to maintain desired rotational speed depending on the nature of application and yarn source, application like pretension when yam is dragged from the offline source and relaxation in yam when it is coming from online source.

[0085] F. The stabilization is arranged at an inclined position with respect to the stabilization roller to maintain the uniform gap between the wrapped yarn.

[0086] G. Observing the variation in travels distance of intake yarn (5) and several support elements (20) thereby creating drags, resulting in yarn suffering tension variation along the path as a swaying motion and variation in gap in between the wrapped yam.

[0087] H. Controlling the variation by adjusting the stabilization roller angle, either manually or electronically.

[0088] I. Exiting the stabilization roller unit resulting in stabilization of the yarn with controlled tension variation.

[0089] J. Repeating the steps D to I if tension variation is not controlling, thereby sending yarn (5) in another stabilization unit as shown in fig 5.

[0090] K. The said stabilized yam then further routed to the further stage (depends on the number of stages of yarn stabilization) of tension control which is moving arm mechanism (7).

[0091] L. Now entering the stabilized yam onto the moving guide wheel (8) of the moving arm mechanism (1) which mounted on the moving arm (9).

[0092] M. The said Moving arm mechanism (7), further maintaining the adequate tension in the yam path by applying constant or variable pressure on the yam over the moving guide wheel supported by pneumatic cylinder (16) or spring drive, thereby maintaining and controlling tension during winding withing the control range.

[0093] N. Now the yarn (5) with adequate tension continues to wound on the revolving core (17) to get a good quality bobbin.

[0094] As the core (17) revolves with the yarn (5), layer of the wounded yarn increases, this increases the diameter of the wounded yarn on revolving core (17), the increase in diameter pulls the yam with speed more than the set surface speed, the following example will illustrate shown in Fig.3, ‘v’ is the surface speed of the upper layer of wounded yarn, ‘r’ is the half diameter of the wounded yam, ‘co’ angular speed of revolving core (17), for any instant, using a simple formula ‘v=r*co’ as ‘r’ increases, if ‘co’ remain the same at that instant, surface speed ‘v’ will increase with increase in diameter, this pull in the yam with the higher speed than an instant before. As the yarn is moving at a certain line speed ‘u’, the abrupt speed change will result in the tension increase in the yam path. This increase in tension in yarn path, the yarn over the moving guide wheel (8) gets pulled due to the abrupt tension increase, results in the shift of the moving arm (9). The shift in position and angle ‘0’ of shift of moving arm (9) is sensed by the sensing device (13) installed behind the pivot pin (14) which signals the central control unit of the winding machine (21) to increase the angular speed ‘co’ of the revolving core (17) as per the angle ‘0’ of shift of the moving arm (9). When the angular speed ‘co’ increase, the tension in the yarn decreases, the angular speed increases till the surface speed becomes ‘v’ again. The tension decrease makes the yarn relax over the moving guide wheel (8), which makes the moving arm (9) to shift back, the moving arm is supported by the in this case a friction less pneumatic cylinder which is controlled by electro pneumatic system. This supports the moving arm (9) to gradually and precisely regain it set position without any jerk or overshoot from the set position, thus controlling the required pressure to maintain adequate tension in the winding

[0095] While the above description contains much specificity, these should not be constmed as limitation in the scope of the invention, but rather as an exemplification of the preferred embodiments thereof. It must be realized that modifications and variations are possible based on the disclosure given above without departing from the spirit and scope of the invention. Accordingly, the scope of the invention should be determined not by the embodiments illustrated, but by the appended claims and their legal equivalents.

Claims

Claims:

1. A yam tension control device for use in winding an intake yam (5) onto a revolving bobbin core characterized in that said device comprises multiple stages of control.

2. The device as claimed in claim 1, wherein said multiple stages of control comprise at least two stages.

3. The device as claimed in claim 2, wherein the total number of stages is three or more and wherein the sequentially last stage is a moving arm mechanism and all other stages preceding the said last stage comprise individual stabilisation roller units.

4. The device as claimed in claim 2, wherein the first of the at least two stages is a stabilisation roller unit (1) and the second of the at least two stages is a moving arm mechanism (7).

5. The device as claimed in claims 3 and 4, wherein said stabilisation roller unit (1) comprises a yarn aligner support (4), an accumulator roller (3), a stabilization roller (2), and an accumulator roller drive motor (6), wherein said intake yam (5) passes from said yarn aligner support (4) which aligns and guides said yam (5) onto said yarn accumulator roller (3), following which said yarn (5) gets wrapped around said accumulation roller (3) and said stabilization roller (2) in a number of wraps, thereby stabilising the tension in said yarn (5).

6. The device as claimed in claims 3 to 5, wherein said moving arm mechanism comprises a moving guide wheel (8), a moving arm (9), a pivot pin (14), a moving arm stopper (12), an exit guide wheel (10), a low friction cylinder (16), and a balance weight (15).

7. The device as claimed in claim 6, wherein said stabilized yam is fed to a traverse mechanism (22) and then onto a revolving core (17) through said moving arm mechanism (7), wherein said yam (5) passes over said moving guide wheel (8) and wherein said moving arm (9) that moves around said pivot pin (14) and within the constraints provided by said moving arm topper(12), said moving arm (9) being supported by a low friction pneumatic cylinder (16), said cylinder (16) being capable of applying adjustable air pressure controllable by an electro-pneumatic system.

8. The device as claimed in claim 5, wherein said accumulation roller (3) is positively driven by a motor (6) with the speed of said accumulation roller (3) being controllable.

9. The device as claimed in claim 5, wherein said stabilisation roller (2) is provided at an adjustable angle, wherein said angle of the stabilization roller (2) being the angle of the central axis of the stabilization roller (2) has with the angle of the central axis of the accumulation roller (3).

10. The device as claimed in claims 1 to 9, wherein in the case of the said source being online, said accumulation roller (3) reduces the tension in said intake yarn (5), whereas in the case of said source being offline, said accumulation roller applies pre-tension in said intake yarn (5).

11. The device as claimed in claims 7 to 10, wherein the configuration of said moving arm mechanism (7) is selected from the following options: a. positioned horizontally, vertically or in any other angular position; b. designed with or without a balance weight (15), that is adjustable or fixed in nature; or c. designed to deliver spring or pneumatic force of fixed or variable nature to the yarn getting wound on the core (17)12. A process of controlling tension while winding an intake yarn (5) onto a revolving bobbin core of a winding machine (21) using the tension device as claimed in claims 1 to 11, characterized in that said process has the following sequential steps:A. passing an intake yarn (5) from of a source over a support element (20) provided on said winding machine (21) to get wound of revolving core (17) of the winding head (19), thereby readying said intake yarn for feeding to a stabilization roller unit (1);B. entering said intake yarn (5) into a yam aligner support (4) of saidstabilization roller unit (1) thereby aligning the yam for passing over an accumulator roller (3) of said stabilization unit (1), thereby making starting point of the yarn on accumulator roller (3) same for all winding heads of said winding machine (21), wherein said accumulation roller (3) is positively driven by a motor (6);C. wrapping the intake yarn (5) several times on the accumulator roller (3) and a stabilization roller (2), wherein the stabilization roller (2) is arranged at an inclined position with respect to the accumulator roller (3) to maintain the uniform gap between the wrapped yarn (5);D. adjusting the speed of the accumulator roller (3) for maintaining a rotational speed to apply pretension to the yam when the yarn of step A is being fed from an offline source and to apply relaxation to the yarn when the yam of step A is being fed from an online source;E. controlling the variation in travels distance of intake yarn (5) and several support elements (20) by adjusting the angle of the stabilization roller (2), thereby eliminating the yam drag and consequently eliminating tension variation along the yam that results from swaying motion and variation in gap in between the wrapped yarn;F. exiting the stabilization roller unit (1) resulting in stabilization of the yarn with controlled tension variation;G. repeating the steps C to F to achieve full control over tension variation and thereby sending yarn (5) to a moving guide wheel (8) mounted on a moving arm (9) of a moving arm mechanism (7) for further stabilization;H. maintaining adequate tension in the yarn (5) by applying constant or variable pressure on the yam over the moving guide wheel (8) supported by a pneumatic cylinder (16) or a spring drive of said moving arm mechanism (7), followed by continuing to wind the yarn (5) on the revolving core (17).

13. The process as claimed in claim 12 wherein the adjustment to the angle of the stabilization roller (2) of step E is carried out either manually or electronically.

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