TWI780300B - Method and improved yarn feeder system and device for optimising yarn feed to a textile machine operating highly discontinuously or with alternating motion - Google Patents

Abstract

A method and a system according to the invention comprise the use of a device (2) for feeding yarn (F) to a textile machine (T), operating discontinuously or with alternating motion, and a device (1) compensating for changes in the conditions for feeding or taking up the yarn (F) by the textile machine (T), said compensator device (1) including a movable compensating means (13) that performs this compensation to maintain a constant tension in the yarn (F) even when the aforementioned change in the conditions for feeding or taking up the yarn occurs, said compensating means (13) being rigid and connected to an electric actuator, a control unit of this actuator being capable of detecting displacement of said compensating means (13) from a predetermined resting position when there is a change in take-up or feeding of the yarn and being capable of returning said compensating means (13) to the resting position after such a change. Provision is made for continuously detecting the yarn tension and operating the electric actuator to maintain this tension at a constant value.

The compensator device (1) used in this system operating according to said method is also claimed.

Description

Method and improved yarn feeder system and device for optimized yarn feeding to textile machines operating in highly discrete or alternating motions

The object of the invention is a method of feeding yarn to a machine and processing the yarn by the machine in accordance with the terms of the preamble of the main claim. A system and compensator arrangement according to the terms of the preamble corresponding to the characteristics of the independent claim are also subject of the present invention.

Fixed tension yarn feeders have long been known for feeding yarn or wire to textile machines to make a final product (for example, a knit or a sock) or to process the yarn possibly in combination with other yarns ( For example, a machine that prepares yarn for subsequent use).

In particular, known types of yarn feeding devices are known which are able to feed yarn (comprising metal wires) or (textile/technical) yarn at a fixed tension. These devices operate according to a known closed loop control principle and implement this closed loop control principle by means of a known fixed tension yarn feeder. The method of control ensures regular feeding of yarn or wire at a fixed tension regardless of the yarn feed rate and regardless of changes in the yarn tension where the yarn is introduced into the fixed tension yarn feeder; all of the above Whether the change in tension is due to running out of the spool of yarn, or such change is due to tearing or extra tension from the irregular winding of the yarns.

A known fixed tension yarn feeder of the above type is for example the subject of European patent application No. EP1492911 in the name of the applicant; this previous document describes a feeder comprising a tension sensor, a Actuator or motor on the wheel or pulley, and a control unit (or electronic control unit) capable of estimating the yarn tension by comparing the yarn tension measured by the sensor with a desired operating tension (or set point) device). Based on this comparison, the control unit acts on the motor to either brake or feed the yarn to act on the pulley connected to the motor, thereby correcting or maintaining a fixed tension of the yarn fed to the textile machine (for production a product or treatment of the yarn itself).

It is also known to discontinuously feed the yarn; or to move the yarn in at least one first and at least one second state which are different from each other according to a yarn, to feed or take up the feed yarn from the textile machine to the textile machine. Devices and systems (and methods of implementing the same). Such different feed states follow each other over time.

For example, a fixed tension yarn feeder is known, which includes means, such as a dynamometer, capable of measuring the controlled yarn tension in real time; a pulley, on which the yarn is wound in one or more turns; a An electric motor drives the pulley to rotate; and a control electronic device adjusts the rotation speed of the motor and the resulting rotation speed of the pulley according to the tension of the measured yarn; to maintain the measured tension with a predetermined and Programmable value matches, which may vary with the operating phase of the textile machine. The rotation of the motor is usually controlled in two directions: one to deliver the yarn to the machine, and the other to withdraw the yarn from the machine during stop or reverse phases to prevent the yarn from becoming slack and keep the yarn at the desired tension.

With this type of feeder, the yarn is picked up directly by the device from the spool and wound onto the pulley. Obviously, to ensure a good quality of fixation of controlled tension, there must be no slippage between the yarn and the pulley; only in this case can the control electronics actually calculate exactly the Coupled with the set speed of the motor, to maintain the tension at the desired value.

In applications where the machine take-up rate is fixed or there are no major discontinuities in the machine take-up rate, this type of feeder device can be changed in the feeding state (variable yarn tension at the feeder introduction, feed rate change, etc. ), maintain a fixed measuring tension. Obviously, since there is no slippage, the feeder is able to keep the measured tension exactly in line with the set value under these operating conditions, while at the same time accurately measuring the quality of the fed yarn, which is defined as Another essential parameter to ensure the quality of the final product.

However, known solutions of the above type do have operational limitations when the speed of take-up of the textile machine changes suddenly. In applications of this type, such as in knitting machines where the rate at which the yarn is taken up changes very rapidly after needle selection in a weaving machine; Following these changes in take-up, tension peaks will occur in the yarn as take-up increases and relaxation occurs as take-up decreases.

These two flaws in tension control (peak and slack) can cause quality problems in the production of garments (weaving defects due to incorrect tension during the process), or cause yarn breakage (due to tension peaks), or cause yarn Falling (caused by slack) from the means of operation (such as needles) of a textile machine.

Obviously, the bigger the problem, the less yarn elasticity there is to help compensate for the lack of dynamics in the motor's response.

Various solutions to this type of problem are known: for example, a feeder system is known from European Patent No. EP2262940 in the name of the applicant, comprising a compensator device connected to the feed (present above-mentioned type) and help to overcome the above-mentioned limitations by cooperating with the yarn. After the yarn has been wound onto the pulley of the feeder, the system requires the yarn to be routed to a movable arm of the compensator device and then redirected to the load cell of the feeder. In this way, the compensator device is located within a control loop (measuring the tension with respect to the speed of the feed pulley) to ensure that a constant yarn tension is maintained as the position of the movable arm varies.

In other words, according to the aforementioned previous document, the movable arm acts as a compensator device between the pulley (on which the yarn accumulates) and the tension detection means (dynamometer) and is able to compensate when the yarn passes through the A change in the state in which the yarn is fed or wound for each state of winding of a textile machine. This maintains the yarn at a set value of fixed tension even during any change in the state in which the yarn is fed to the textile machine.

The movable arm of the known solution consists of a spring, such as a helical spring, the terminal part of which includes an eyelet, for example made of ceramic, for the passage of the yarn, enabling the arm to perform its compensating function.

When using the compensator device, the operator adjusts the spring force (manually or electronically) so that the end of the compensator device through which the yarn runs is centered on average during the working phase of an angular working sector. In this way, if the winding of the textile machine changes, one of the following situations can arise: - During a sharp winding increase, the pulley motor cannot follow (compensate) due to its limited dynamics, the compensating arm will drop, allowing The motor has time to speed up and reduce the tension peak off the feeder; or - during a sharp take-up reduction the motor is unable to follow due to its limited dynamics, the compensating arm will rise allowing the motor time to slow down and reduce the off-feed The tension of the device is relaxed.

Clearly, the ability to compensate for tension peaks and yarn slack is closely related to the dynamics of the system (spring force) and the magnitude of the angular sector the arm can move within the angular sector.

It should also be noted that the aforementioned previous document provides the possibility to measure the position of the compensating arm used to increase or decrease the speed of the pulley by means of the control electronics of the feeder, and to adjust the force of the spring through an electronic actuator Possibility to have the spring work automatically without manual adjustment of the force by the operator.

Although operating optimally, this known solution has limitations, which will be explained below.

The compensator device of this known system actually operates like a balance and the force of the spring is adjusted manually or automatically to ensure that the force of the spring can compensate the tension of the yarn being fed to keep the end of the spring in motion At the center of the corner sector. The lighter the spring (in terms of weight), the more correctly the spring force will be calculated and the more the spring will increase the responsiveness of the system. However, it is clear that the force of the spring is also related to the operating tension limit within which the device can effectively operate.

For example, for a specific application (say 10 grams), the spring is calibrated for medium-high tension, and the force of the spring must be calculated accordingly; conversely, when the working tension is lower, the selected force will constitute the an operating limit.

Therefore, known compensator devices have significant limitations, so that the spring must be dimensioned according to the desired operating tension, resulting in inelasticity of the system, or the spring must be dimensioned differently by the operator, or the entire The compensator device must be determined with different specifications and sizes as the working tension changes. These scenarios are of course not always possible.

Besides that, since the end of the compensating arm is part of the spring, it also undergoes bending due to the force of the yarn, and this will make readings of its position inaccurate and therefore difficult to use as a predictor The signal is used to anticipate any compensation by the device to change the state of the yarn take-up; also because the spring is flexible it is difficult to keep the spring in a specific position.

Finally, the compensation capability, especially during the relaxation phase, is closely related to the length of the arm and the magnitude of the angular sector; thus this capability is limited.

U.S. Patent No. US4752044 is about a yarn feeder device with electronic tension control. The device comprises a casing, on one side of which there are rotating means, on which the yarn leading to a textile machine is wound, the yarn having previously cooperated with braking means, which is connected to the casing Associated. At the output of the rotating means, the yarn passes through a fixed eyelet and then through an eyelet at the end of a movable guide arm forming an integral part of the known yarn feeder device part; at the output from the eyelet of the guiding arm, the yarn cooperates with another fixed eyelet before leaving the device.

The yarn guiding arm is intended to form a reserve of yarn F on the outlet side of the rotating means, and thus downstream of the rotating means when the yarn feed is slowed down due to changes in the yarn take-up of the textile machine .

The yarn guiding arm can be attached directly to a permanent magnet DC electric motor housed in the housing of the device, or the yarn guiding arm can cooperate with a rod which in turn is connected to the device. The integral part is moved by an electric motor inside the housing. In two embodiments, a photoelectric sensor detects the angular position of the guiding arm and emits a signal representative of the tension of the yarn being fed and at the same time representative of the angular position of the arm and thus representative of the torque generated downstream of the rotating means. The signal of the size of the yarn reserve.

The (DC) electric motor forms an electromagnetic control transducer which exerts a carefully predetermined and adjustable control force on the guide arm. This force is equal to the tension exerted by the yarn on the eyelet of the guide arm.

The force is adjustable by means of a potentiometer in a circuit that includes a power supply unit that provides power to the DC motor. In the circuit, a compensation signal is defined, applied to the control input to the power supply, which signal is set (and therefore at a fixed value) to correspond to a specific yarn tension.

In this way, the power supply unit controls the DC motor to define an equilibrium position of the guide arm, which can be maintained under yarn tension.

More specifically, in normal operating conditions, the guide arm occupies a certain equilibrium angular position between two blocking pins, between which the arm is angularly movable. The force exerted by the yarn attached to the eyelet of the arm is balanced by the force of the DC motor acting on the rod, or on the arm itself.

In the event of a change in the state of the yarn feed, such as when the textile machine uses less yarn, the guide arm is angularly moved about the initial equilibrium position to generate an electrical signal corresponding to the change in position through the aforementioned sensor. The signal is passed to the means of controlling the device. This means acts on the feed of an actuator controlling the rotating means to act on the yarn feed rate until the guide arm returns to a predetermined equilibrium position. In the given equilibrium position, the yarn tension is compensated by the control force exerted by the rod on the arm, generated by the electric motor connected to the rod, or the yarn tension is compensated by the control force exerted by the rod in connection with the movable The motors acting in conjunction with the arms generate a balance of forces directly on the movable arms.

Thus, through the movement of the guide arm, the known solution is able to detect a change in the state of the yarn feed, which is compensated by a corresponding action on the rotary feeder device. In this solution, the guiding arm is directly or indirectly acted upon by an electric motor whose function is only to balance changes in the tension of the yarn to keep the guiding arm in the rest position. However, the guide arm, and the actuators cooperating directly or indirectly with the guide arm, as only act on the actuators of the means of rotation, cause the arm to rest in a position of equilibrium, or rest on the arm Returns to an equilibrium position after angular movement between fixed pins (attached to the housing of the device) and thus has a fully passive function. Such guide arms are always subjected to a given force and can only compensate limited changes in yarn tension due to their limited movement between the fixed pins.

International Patent Application No. WO2005/111287 describes a yarn feeder device comprising a sensor capable of reading the tension of the yarn being fed to a textile machine, and rotating feeding means controlled by an electric motor. The movement of the means is controlled by a microprocessor unit which adjusts the speed of the means in dependence on the yarn tension detected by the tension sensor. The sensor is located at the free end of a rigid arm that is capable of abutting against the yarn as the yarn changes tension at the output from the rotating means and passes over an idler rotor or pulley associated with the free end of the movable arm. A blocking element moves. Resistance to movement of the arm may be achieved by a spring, or a trolley moving along a track associated with the feeder device.

The swivel means and the movable rigid arm are an integral part of the known feeder device.

In working condition, the yarn is wound on the rotating means at least once before passing the pulley at the end of the rigid arm. The movement of the yarn causes the arm to rotate in a direction following the yarn feed direction, and this rotation is resisted by one of the counter elements (spring or trolley), adjusted by the operator. The tension sensor detects the yarn tension, compares the yarn tension to a fixed value, and then adjusts the speed of the rotating means to keep the yarn tension close to the desired value. The movement of the rigid arm prevents any excessively rapid increase in yarn tension by moving back, thus preventing yarn breakage.

Also, the movement of the rigid arm is limited within a predetermined angular sector.

In the two known solutions of the two previous documents described above, the device in U.S. Patent No. US4752044 or the device in International Patent Application No. WO2005/111287 are elements incorporated in the compensating device instead of Separable or capable of being independently constituted. The result is a high degree of complexity in realizing the known solution, and very difficult and high costs in performing any maintenance work.

The international patent application No. WO2013/064879 filed in the name of the applicant describes a method and system based on the preamble corresponding to the characteristics of the patent scope of the independent item of the document.

This prior document describes a metal feeder device comprising a body with wire stop means; one or more pulleys; controlled by respective motors, on which the wire is wound; a wire, upon reaching the operating machine Before passing through the compensator means and the tension sensor. The control electronics are capable of continuously measuring the wire tension so that the wire tension and the A given value matches.

The compensator means also comprise a compensating arm having a free end that cooperates with the wire and is then free to rotate about a pin fixed to a bracket associated with the body. The arm can thus move within the body of a given angular sector by approaching or moving away from the tension sensor (defined by the dynamometer).

The compensating arm is associated with a spring connected on one side to a support fixed to the body of the device and on the other side connected to the compensating arm by means of a movable trolley An electric stepper motor moves through an Archimedesian or infinite spiral.

Therefore, the compensating arm is not directly connected to the electric motor, but the electric motor drives and moves the compensating arm through other components interposed, each having its own inertia.

The compensating arm is associated with a position sensor connected to the control unit, so that the position sensor is able to measure the position of the arm within a defined angular sector.

The compensating arm is thus able to counteract the slippage of the wire in a non-static but dynamic way: the control unit can actually change the position of the trolley (acting on the electric motor) to which the spring is attached, so that the trolley acts on the The force on the arm changes and brings the arm to the desired position within the predetermined angular sector. In this way, the compensating arm keeps the wire constantly correctly stretched on the dynamometer or tension sensor, especially during the phases when the wire is not being fed to the textile machine.

The compensating arm also creates a reserve of wire from which the machine can draw during unforeseen speed changes.

The previous document under discussion goes on to describe a feeder device equipped with an integrated and inseparable component compensating arm that is free to move within a defined angular sector.

The control system of the device knows the position of the arm and can define the force applied through a system of electric motor, and a spring(s) from the measured tension or read position, thus closing the two Possible control loops, namely a second loop for tension (the first loop being the loop for the motor connected to the pulley) and a possible second loop for the position of the arm.

It should be noted, however, that the force applied to the arm is handled through a system of springs, and a movable trolley driven by an electric stepper motor used to change the fulcrum of the lever, and thus the electric motor The force applied to the wire.

Even, in this previous document, the problems pointed out with respect to the system described in the above-mentioned European Patent No. EP2262940 still apply.

In fact, the ability to compensate for tension peaks and slack in the wires of the device, which is the subject of International Patent Application No. WO2013/064879, is related to the dynamics of the system (spring force, moving trolley and motor) and the compensation arm at The magnitude of movement within the angular sector is closely related.

Also, even in this previous document, the compensating arm actually operates like a balance and the force of the spring is automatically adjusted so that the force of the spring can compensate the tension of the wire being fed to keep the terminal part of the spring in the movement The center of the corner sector.

Finally, the compensation capability, especially during the relaxation phase, is closely linked to the length of the compensation arm and the magnitude of the angular sector; the capability is thus limited.

Besides this, the known feeder device is inseparably incorporated into the compensator means. The result is a heavy assembly with non-tiny dimensions.

The object of the present invention is to provide a method and system for controlling the feeding of a discontinuously fed yarn comprising a yarn feeder associated with a device for compensating for changes in the yarn taken up by a textile machine couplet.

In particular, the object of the present invention is to provide a system of the above-mentioned type with a compensator device inserted into a control loop when feeding yarn to a textile machine (measuring the tension with respect to the speed of the feed pulley) In , this will overcome the limitations of existing solutions.

Another object of the present invention is to provide a method of the above type which can be actively or dynamically compensated during the aforementioned discontinuous feeding to the textile machine, during feeding of the yarn to the textile machine and removal from the textile machine. During the second phase of the yarn, during which such feeding is interrupted, any tension to which the yarn is subjected changes.

Yet another object of the present invention is to provide a self-contained compensator device suitable for use in systems of the above type, which does not change the dynamic characteristics with respect to the set operating tension, making the device flexible and easy to use.

Another object of the present invention is to provide a compensator device of the type mentioned above, which allows precise measurement of the position of the compensating means and which also allows the yarn to be subjected to changes in tension at the beginning of the discontinuous feeding of the different stages of the textile machine, Operates in a predictive manner.

Yet another object of the present invention is to provide a small compensator device thereof, which can also be applied as an additional element to a feeder device allowing the system to which the small compensator device belongs to be recovered during relaxation or reversal of the textile machine compared to known systems The most recyclable yarn.

Those skilled in the art will appreciate that these and other objects are achieved by methods, feeder systems, and compensator devices according to the appended claims.

1‧‧‧Compensator device

2‧‧‧Feeder

2A‧‧‧end

3‧‧‧tension sensor

4‧‧‧wheel

7‧‧‧The first part

8‧‧‧Electric motor

10‧‧‧Second part

11‧‧‧Ontology

13‧‧‧arm

14‧‧‧end

16‧‧‧ring body

18‧‧‧Magnet

20‧‧‧Linear Hall Sensor

26‧‧‧drum or cylinder

60‧‧‧Control unit or electronic device

70‧‧‧control unit

80‧‧‧rest position reference point

81‧‧‧The position of the arm

82‧‧‧The location of the driving motor

F‧‧‧yarn

the curve

K‧‧‧curve

M‧‧‧axis

T‧‧‧Textile Machinery

W‧‧‧Curve

Y‧‧‧curve

For a better understanding of the invention, the following figures are given as non-limiting examples only, wherein: Figure 1 shows a front view of a compensator device according to the invention associated with a known feeder device for control The tension of the yarn being fed to a textile machine; Figure 2 shows a side view of the device shown in Figure 1; Figure 3 shows a perspective view of the compensator device according to the invention and the feeder device of Figure 1; Figure 4 shows a front perspective view of a compensator device according to the invention; Figure 5 shows a side view of a compensator device according to the invention; Figures 6 to 8 show a view from above and in three different positions of use Compensator device; Figure 9 shows a view from below the compensator device according to the invention; and Figures 10A to 10C show the different block diagrams used for the system according to the invention; Figures 11A to 11C show Diagrams for the tension of the yarns of the textile machine, respectively, when the device which is the subject of the invention is not in operation (Fig. 11A), and with the system according to the invention in passive-dynamic mode (Fig. 11B) and according to Two cases of active-predictive mode (Fig. 11C) operation.

Referring to the foregoing drawings (wherein corresponding parts have the same reference numerals), in particular Fig. 1, a compensator device according to the invention is generally indicated at 1 and is similar to a feeder device or a feeder device known per se. A feeder 2 for short, one end 2A is associated (or is located on one side of the feeder) to feed a yarn F (shown in dashed lines in Figure 1 ) to a textile machine T at a fixed tension. The yarn F can also be a wire and can be fed to a handling machine such as a winder. In contrast to the feeder 2, the device 1 is a complete and clearly identifiable element both in construction and in use.

The feeder 2 has a tension sensor 3, a pulley 4 (or equivalent yarn accumulation means) and a control unit or electronics 60, the pulley being driven by its own electric motor (not shown), the control The unit preferably has a microprocessor known per se (see Figures 10A to 10C). When a yarn is fed to the textile machine, the control unit or electronic device can estimate the tension of the yarn detected by the sensor 3, compare the detected tension with a predetermined value (or set point value) comparison, and check and adjust the tension of the yarn (if the tension of the yarn is different from the desired value) through the action on the electric motor and therefore on the pulley 4. The feeder 2 and its components 3, 4 are of known type and operation and will therefore not be further described.

The feeder already mentioned feeds the yarn at a fixed tension to the textile machine used in one of the production units of the article, or in one of the machines for processing the yarn.

According to the invention, the device 1 and the feeder 2 define a feed system for the yarn F.

The compensator device 1 according to the invention is able to cooperate with the yarn after it has passed the pulley 4 . The compensator device is therefore within the yarn tension control loop, as can be seen from Figure 1 and will be apparent from the description of the method according to the invention. Based on the present invention, it is possible to increase the dynamic performance of the feeder system so that the feeder system can immediately compensate for sudden changes (positive or negative) in the yarn take-up, allowing the pulley motor to change as required by the new take-up state. Feed the yarn at a new speed without causing positive or negative tension peaks in the final yarn tension.

The presence of the compensator device 1 in the control loop always ensures that the tension of the yarn leaving the feeder 2 is always the same as set.

The compensator 1 is a stand-alone device in contrast to the feeder 2 and includes an electric motor 8, for example a DC brush motor, preferably of very low inertia to enhance its dynamics. In an exemplary embodiment of the invention, the motor 8 directly moves a drive shaft having two parts protruding from the two phase sides of the motor itself. In the drawings, the first part of the drive shaft is indicated at 7 (see Figures 7 to 9) and the second part at 10 can be seen in Figure 9; the motor is also inserted into the Inside one body 11 of the device. A rigid arm 13 (thus attached to the drive shaft itself) is mechanically attached to the first portion of the drive shaft. At one end 14 of the arm 13 there is also a ceramic (or other material) annular body (or an other shape) 16 over which the yarn is tied.

The already mentioned electric motor 8 preferably has a very low moment of inertia to allow the arm 13 to move quickly under the force of the yarn, and thus quickly compensate for this movement without causing tension peaks in the yarn itself.

However, when the motor has very low inertia (preferred) and when the arm 13 has finite inertia, the arm is free about an axis M (or the axis of the drive shaft) if it is pulled by the yarn F. (causing the motor to rotate); in each case, the arm has a zero or initial rest position (such as seen in Figure 6), which occurs when the yarn F is taken up by the textile machine T. Used when there is no tension change and no interruption. The arm can also assume other compensating positions, as explained below.

The assembly of the arm 13 and the motor 8 (ie, essentially the device 1 ) can operate in two different modes: passive-dynamic or active-predictive.

In passive-dynamic mode, the motor allows the arm 13 (attached to the drive shaft) to be pulled by the yarn and move from its rest position while also causing the motor itself to rotate. However, the motor acts after this movement to return the arm 13 to the rest position. In this mode or mode of operation, the motor operates roughly as a "dynamic" spring, and the force of the motor (what the motor acts on the arm 13) can be programmed by programming and/or controlling the motor torque.

However, this force is not predetermined and fixed (as in the solution in US Pat. The arm is kept in its intended position regardless of the yarn setting operating tension for each particular stage of production of the article. This will enable the motor 8 to hold the arm in its equilibrium position (such as in Fig. at "3 o'clock").

The variability in the motor's opposing force or effect on the arm 13 will be described below.

In active-predictive mode, the motor 8 is able to act in advance in "predictive mode" as soon as it detects a change in yarn tension (detected by the sensor 3) due to a change in the operating phase of the machine. In this case, the motor 8 moves the arm 13 carried by the drive shaft to a compensation position capable of compensating for the change in tension: if the change in tension tends to increase, the motor 8 moves the arm to "6" in Fig. 7 If the change tends to reduce the yarn tension (because the textile machine has stopped or slowed down the yarn take-up), the motor moves the arm 13 to "12 o'clock" in Fig. 8 The compensation position at the "clock". In this way, regardless of the operation and production stages of the textile machine T, a constant yarn tension can be maintained.

Figures 11A to 11C show the tension curves for various states of motor-arm assembly or device 1 failure (Figure 11A), passive-dynamic mode (Figure 11B) or active-predictive mode (Figure 11C) .

In these figures, the curves or lines F, K, W and Y delimit the set yarn tension (in the production operation phase, curve F), the measured yarn tension (curve K), the set point of the arm 13, respectively. position (curve W) and the actual position of the arm 13 (curve Y). In these diagrams, time is the abscissa, and the ordinate is the measured tension of F and K and the position values of W and Y.

It can be seen from the comparison diagrams that when the device 1 fails, the measured yarn tension has significant peaks and fluctuations compared to other states in Fig. 11B and Fig. 11C. It can also be seen from the comparison of Fig. 11B and Fig. 11C that when the device 1 acts in the active-predictive mode, the yarn tension has relatively limited variation. Finally, it can be seen in Figure 11C that the rest position (curve W) of the arm 13 is not fixed, but changes with the yarn tension; during the compensation performed by the device 1, this rest position is also determined by the "current" position of the arm. The location "follows".

The second part 10 of the drive shaft supports a magnet 18 which together with the arm 13 associated with the motor 8 is free to rotate around its axis M within a certain circular sector (causing the drive shaft to rotate). Alternatively, the assembly comprising arm 13 and magnet 18 is free to rotate to achieve a complete revolution about the axis of rotation M (the axis of the drive shaft); in other words, both arm 13 and magnet 18 are slotted On the drive shaft, both are caused to rotate about the axis M in the same way, ie freely or within an angular sector. This will enable the position of the arm 13 to be known immediately by detecting the position of the magnet.

For this purpose, there are position detectors surrounding the magnet, such as one or more linear Hall sensors 20, which are able to generate a position signal, which is sent to a control unit, such as the compensator device 1 70. Based on the Hall sensor data, the unit 70 is able to convert the motor rotation into two sinusoids (sine and cosine) offset by 90°. Thereby, it is possible to obtain instantaneously the absolute position of the shaft, and therefore of the arm 13 which is coacting with the yarn, to which the shaft and the magnet 18 are rigidly attached.

In an embodiment, the control unit also preferably includes systems (known per se) to drive the electric motor to control the rotational speed and applied torque of the motor.

Preferably, an instant data exchange between the control electronics 60 of the feeder 2 and the control unit 70 of the compensator device 1 is also provided in order to be able to set a desired torque for the motor of the device 1 and then control the torque of the motor. Rotate and read the position of the motor (and consequently control the position of the arm 13 in a direct and immediate manner). Since the torque setting depends on the set yarn tension, or the yarn tension detected by the sensor 3, it is dynamic and not fixed.

Information exchange can occur in one of the following ways: through any serial bus, through digital or pulse width modulated (PWM) signals, or through analog signals.

Thus, the feeder 2 cooperating with the compensator device 1 (via the control electronics of the feeder) is obviously able to know the position of the arm 13 in a reliable and immediate manner and the adjustments to be applied to the compensator device 1 The torque/offset/speed of the motor. This is due to the direct connection of the drive shaft to the arm, or due to the direct action of the motor on the arm.

By suitably processing the received position signal of the arm 13 and suitably controlling the motor acting on the arm, the feeder system of the yarn F according to the invention is thus able to close a system for the arm 13 in an almost immediate manner. A second control loop for the position of the arm, and when the set tension changes, maintains the arm in a desired position, such as the center position of the arm ("3 o'clock"). This is to compensate for yarn movement and yarn tension changes linked to the various operating stages of the textile machine.

Please refer to Figure 10A and Figure 10B, the system can be implemented in different ways:

1. The compensator device 1 has its own control unit 70 which is intended to receive a rest position reference point from the control electronics 60 of the feeder 2 (indicated by block 80 in Figures 10A and 10B) , the arm must maintain the rest position reference point when setting the tension of the yarn F or detecting tension changes. The control unit 70 cooperates with this means (magnet 18) to measure the position of the arm 13 and the drive motor 8 (blocks 81 and 82). Thus, the control unit closes the control loop for the position of the arm 13 .

2. Alternatively and preferably, the control electronics 60 of the feeder 2, which receives information about the position of the arm 13 from the magnet 18, and as a result sets the torque value of the motor 8 to close the control loop for this position (based on set yarn tension or detected yarn tension). In this case, the drive means for the motor 8 can be located in the control unit 70 of the compensator device 1 , to which the reference point is transmitted via the feeder, or in the electronics 60 of the compensator 2 (as described below). Since the control electronics 60 of the feeder 2 know not only the position of the arm, but also directly the measured tension of the yarn (connected to the tension sensor 3), and can then use both information to optimize the The performance of the system, so this solution is the best one. For example, if such electronic devices detect that the yarn tension has increased due to a sudden yarn demand from the textile machine T, the electronic devices can determine, for example, by moving the position set point of the arm 13 from "3 o'clock" to " 6 o'clock" to automatically change the position set point of the arm. This is based on the active-predictive mode of the assembly of the motor 8 and the arm 13, as indicated above.

This function also allows a further reduction of the peak tension, since not only the low inertia of the motor 8, but also its dynamics, is used to compensate the conditions. Likewise, this obviously also applies to the phase of sudden slowing down of the coiling. In fact, all this can be seen from the comparison of Fig. 11C with Fig. 11B mentioned earlier.

The electronics of the feeder system (i.e. the control unit 70 of the compensator device 1 or the electronics 60 of the feeder 2, as described above) read the position of the arm 13 continuously (depending on the position detected in the yarn F). tension) and by properly controlling the torque of the motor and the arm 13 acting together, the position of the compensating arm 13 can be kept at the desired value. This torque value will therefore allow the arm 13 to remain balanced in its rest position, say 3 o'clock, by applying a force to the arm directly through the drive shaft equal and opposite to the yarn feed tension. In this way, there will be no delay in the action of the arm 13, which would otherwise occur in the solution of the international patent application WO2013/064879.

Thus, an increase or decrease in yarn tension will cause the arm 13 to move from its equilibrium position, constantly maintaining the yarn at the set operating tension, as shown in the example below:

a) During processing, the arm 13 will have a distinct tendency to drop (moving towards the "6 o'clock" position in Fig. 7) in case the yarn tension required for the given setting is increased, and the reading of this position change The system electronics (ie the control unit 70 of the device 1 or the control electronics 60 of the feeder 2) will calculate the new torque to be applied to the motor 8 to bring the arm 13 back to this rest position.

b) During processing, in case the set tension needs to be reduced, the arm 13 will visibly tend to rise (moving towards the "12 o'clock" position in Figure 8) and read the feeder for this position change The control unit or electronics of the arm will calculate the new torque to be applied to the motor 8 to bring the arm 13 back to this rest position.

Thus, the feeder electronics will be able to automatically and quickly and precisely control the position of the arm 13 due to the attachment of the compensation arm 13 to the drive shaft, thus enabling the operator to modify the working tension at will during operation, for example during Tension grading is achieved during the production cycle of the article (eg, graduated compression on medical stockings, etc.). Every change in tension involves a change in the motor torque applied to the arm 13, which will always assume that rest position (say "3 o'clock"), or will be brought back to this rest position, to keep the yarn "current "The tension at constant, or the tension at which the yarn is taken up during a particular feeding stage required for a particular production stage.

In other words, the feeder system is provided with a control unit (device 1 or feeder 2 ) incorporating for example a microprocessor for controlling the operation of the motor which directly moves the arm 13 . However, when the winding or feeding state of the textile machine changes so that the tension of the yarn passing through the annular body 16 supported by the arm 13 changes accordingly, the arm, together with the drive shaft to which it is connected, can initially rotate around the axis M Move freely (causing the motor to spin).

Any change in the position of the arm 13 (with respect to a given reference point or rest position, eg "3 o'clock") is detected by the control unit of the feeder system via a signal from the position detection means 19 . These data are supplied to the electronic control unit (60, 70), closing the control loop by the feeder system.

In particular, the control unit 70 of the device 1 is able to detect how much (angle) the arm 13 has moved from the reference position, and the control electronics 60 of the feeder 2 can monitor, vary and control the motor to the pulley 4 based on this value The power supply of the motor causes the motor to change the rotational speed of the motor to compensate for the angular movement of the arm 13 with respect to the reference position. In this way, the feeder 2 uses information about the position of the arm 13 to anticipate changes (acceleration/deceleration of the pulley 4), further improving the quality of the conveying tension. This is based on the "proactive-predictive" mode of operation described above.

Also in this case (as in the case of European Patent No. EP2262940), the compensator device 1 thus acts like a "balance" and the electronics of the feeder system will instantly calculate the torque to be applied to the motor 8, The motor cooperates with the arm 13 to constantly keep the arm in balance in a fully automatic manner. This depends on the "current" tension of the yarn F (apparently maintained at a given tension).

Controlling the position of the arm 13 in this way will also have a compensating effect on the conveying tension, which will lead to a complete elimination or a substantial reduction of tension peaks and slack in the yarn itself. In fact, when the textile machine T suddenly increases its demand for yarn F, and the dynamics of the motor-driven pulley 4 are not sufficient to compensate for this change, the arm 13 will tend to drop (move towards the "6 o'clock" position) and increase the feed to The amount of yarn F of machine T; this increases until the motor of pulley 4 reaches the necessary speed to eliminate or reduce tension peaks. At this point, the arm will automatically return to its original or rest position.

Conversely, when the textile machine suddenly reduces the demand for yarn, and the dynamics of the motor driven pulley 4 are insufficient to compensate for this change, the arm 13 will tend to rise (moving towards "12 o'clock" in Fig. 8) And reduce the amount of yarn F sent to the machine T until the motor of the pulley 4 reaches the necessary speed to eliminate or reduce yarn slack. At this point, the arm will automatically return to its initial or rest position (Fig. 6).

In the first embodiment, the rest position of the arm 13 is within a range of movement of the compensation means or arm 13, which range has two limit positions (i.e. 6 o'clock and 12 o'clock).

Also, the precise and instant knowledge of the position of the compensating arm 13 enables the electronics of the feeder 2 to use its information to speed up or slow down the rotation of the pulley 4 to settle to a new ideal speed for a fixed yarn The F tension is preset to a value and the time it is held at that value is minimized, further limiting the amplitude or slack of tension peaks in the yarn F.

Moreover, the position of the compensating arm 13 and the measured tension value can be accurately and instantly known through the sensor 3 during the transient state (winding change), so that the feeder system can change the force that interacts with the arm 13. The drive of motor 8, to reduce the change of the conveying tension of feeder 2 more; The measured yarn tension will tend to rise; in this case, the electronics of the feeder system can decide to: 1) interrupt the closure of the loop controlling the position of the arm 13, or reduce the influence of the loop so that the yarn can be lowered Arm 13 until the yarn tension is within established limits, so use this interval to move from 3 o'clock to 6 o'clock when a stock of yarn F is to be fed; 2) automatically set the work of arm 13 Set the point to a lower position to provide more yarn F to the textile machine T until the critical state is overcome.

(ii) During the sudden deceleration phase, the arm 13 will tend to rise (moving to the "12 o'clock" compensation position in Fig. 8) and the measured tension will tend to fall; in this case, the feeder system can Decisions: 1) interrupt the closure of the position control loop, or reduce the influence of this loop, so that the arm 13 can recover the yarn F until the tension of the yarn is within the established limits, so use this interval to move from 3 o'clock to At 12 o'clock, take action to recover excess feed yarn; 2) automatically set the working set point or rest position of arm 13 to a higher position to provide less yarn F to the textile machine T until the critical state is overcome until.

So far, the set point or reference value of the position control loop of the compensating arm 13 may be variable and suitably dynamically handled by the feeder electronics, considering for example the "3 o'clock" value (Fig. 6). , in order (for example) to provide a possible subsequent feeding phase; for example, during the phase in which the yarn is slowed down by the textile machine and then stopped, the set point can be automatically shifted to the 12 o'clock position, so that there is a greater The stock of yarn F is provided for the next acceleration at restart, further reducing the next peak.

In yet another embodiment of the invention (already included in the drawings), there is also a drum or cylinder 26 associated with the compensating arm 13, in which the yarn is stored during the recovery phase above, the stock of yarn F will thus be increased because the magnitude of the sector of angular rotation has increased, and in this case will no longer be restricted between 6 o'clock and 12 o'clock, but will be able to rotate around Axis M is free to rotate.

The drum where the yarn is stored can be attached to the arm 13 or rotate freely on bearings that make the rotation of the drum independent. The diameter of this drum determines the maximum amount of yarn F that can be obtained from the device 1 /feeder 2 system. The drum may thus have different dimensions, depending on the amount of yarn F desired to be recovered onto the drum. The drum can be cylindrical, semi-cylindrical, or have a profile with variable cross-section.

The compensator device may work without a mechanical stop preventing the compensator device from rotating beyond the 6 o'clock to 12 o'clock arc, allowing the arm 13 to rotate unrestricted about the axis during the recovery phase. In this case, the arm 13 is free to store the very large amount of yarn stored on the drum 26 during the recovery phase, which will then be fed back to the machine at the next restart.

This will create a double "reservoir" of yarn, ie a drum 26 in addition to the pulley 4 .

Based on the invention, a single "system" is able to work with even wildly different feed tensions, without any action from the operator. This system is able to compensate for sudden changes in the feed without causing tension peaks or slackening of the yarn, and at least to be able to recover a larger amount of yarn F than the previous solutions described in the state of the art.

Various specific embodiments of the invention have been described. Certainly there may be other specific embodiments. For example, the annular ceramic body on the arm 13 could be replaced by a body made of any other material suitable for the application having sliding characteristics. Otherwise, the use of a DC motor with brushes is described herein, but obviously any type of electric motor or actuator (brushless, stepper, etc.) could be used, and pneumatic ones could also be used.

The use of an encoder with Hall sensors to detect the rotation of the drive shaft has been described, but any encoder on the market could be used, or a Hall sensor could be incorporated into the motor; in this case, There is no need for the drive shaft to protrude on both sides.

In addition, the arm 13 is rigid, however the arm may have its own minimal deflection, to further dampen the compensating effect, such deflection originating from the material or profile from which the arm is made. Also, the compensating arm is described as rotating, but could be replaced by an arm following a linear movement using a linear actuator or motor moving longitudinally through positions equal to 6, 3, and 12 o'clock.

Finally, it has been explained that there is a control unit of the device 1 cooperating with the control electronics of the feeder 2 . Obviously, the control unit can be for the feeder 2 (i.e. the control unit can be part of the control electronics) and when the body 11 of the device 1 is attached to the feeder 2, automatically recognizes Acts automatically when the device 1 is present (detects the presence of the body 11 by means of suitable connectors not shown, through which the control unit encodes the motor of the device 1 and the drive shaft associated with the arm 13 device or position sensor means together). This solution is shown in Figure 10C.

The invention applies to the feeding of textile yarns, but also to the feeding of metal wires.

Such modifications are also considered to be included within the scope of the invention defined by the scope of claims below.

1‧‧‧Compensator device

2‧‧‧Feeder

2A‧‧‧end

3‧‧‧tension sensor

4‧‧‧wheel

13‧‧‧arm

26‧‧‧drum or cylinder

F‧‧‧yarn

T‧‧‧Textile Machinery

Claims (16)

A method for feeding a yarn or thread comprising a metal thread at a fixed tension to a textile machine (T) or to a machine for processing the metal thread, the feeding taking place discontinuously, i.e. the feeding takes place in several A sequence of stages takes place in which the yarn (F) is moved in at least one first and at least one second feeding or winding state which differ from each other by the machine, these states succeeding each other in time, the feeding being carried out by A yarn feeder device (2) is implemented, the yarn feeder device has tension detection means (3), yarn accumulator means (4) and control means (60), the yarn accumulator means (4) Driven by its own electric actuating motor, the control means (60) are connected to the tension detection means (3) and the yarn accumulator means (4) and can be based on the tension value to act on the yarn accumulator means (4), providing a compensator means (1), associated with the feeder means (2), before cooperating with the tension detection means (3), Cooperating with the yarn (F) coming from the yarn accumulator means (4), the compensator device (1) is able in each first feeding or winding state and successively in the first feeding or winding state After each transition between the second feed or take-up state, the change of the feed or take-up state of the yarn (F) is compensated, thus allowing the control means (60) of the feeder device to act on On the yarn accumulator means (4), to change its effect on the yarn, and the tension value detected by the tension detection means (3) remains fixed over time and equal to a set value, because The interaction between the yarn and the compensator device (1) maintains a fixed tension also during the stages of changing the feeding states, the compensator device (1) comprising movable compensating means supporting a body (16 ), the body (16) can be in a Cooperating with the yarn (F) at the free end, the movable compensating means can move along the yarn (F) movement in the feed direction, but in the opposite direction when the yarn (F) changes from a larger to a lesser winding state, the movable compensating means returns to the rest position at the end of the winding change, its characteristic In that the movement of the movable compensating means is provided to be controlled by means of a corresponding electric motor (8) of the movable compensating means itself, which is directly and rigidly attached to the movable compensating means and capable of directly controlling the movement of the movable compensating means , the movable compensating means is controlled according to the set or detected tension and position of the yarn, which position is measured during each stage of feeding the yarn (F) to the textile machine, the movable compensating means Department of rigidity. The method of claim 1, wherein the movable compensating means and its electric motor (8) operate in a passive dynamic mode, the electric motor (8) directly and rigorously controls the movement of the movable compensating means, the movable compensating means can moves freely under the force of the yarn (F) together with the electric motor, but is brought back to the rest position after the movement by the electric motor (8), which generates a torque which It is possible to keep the movable compensating means of the yarn (F) in the rest position while feeding the yarn (F) to the textile machine. The method according to claim 1, wherein the movable compensating means and the electric motor (8) controlling the action of the movable compensating means are operated in an active predictive mode, as long as a change in tension of the yarn (F) is detected, the An electric motor (8) immediately moves the movable compensating means from the rest position to a compensating position corresponding to the change. The method of claim 1, wherein continuous control of the electric motor (8) of the compensator device is provided by a control unit (60, 70) directly or indirectly connected to the tension detection means (3). The method of claim 1, wherein the movable compensating means is selectively provided for rotation about a fixed axis (M) away from a drive shaft of the electric motor, the movable compensating means is rigidly attached to the electric motor, or the electric motor The motor moves along the compensator device (1). The method of claim 1, wherein besides the yarn accumulator means (4) of the feeder device (2), the yarn (F) is additionally provided to be accumulated in the compensator device (1 )superior. The method according to claim 5, wherein the movement of the movable compensating means is optionally limited or unlimited in angle. A system for feeding a yarn comprising metal wires or threads to a textile machine (T) or to a wire processing machine at a fixed tension, the feeding being carried out discontinuously, or the feeding being carried out in a sequence of several stages , wherein the yarn (F) is moved in mutually different at least one first and at least one second feeding or winding states of the machine, these states succeeding each other in time, the feeding system according to claim 1 and comprising a feeder device (2) for the yarn, the feeder device having tension detection means (3), yarn accumulator means (4) and control means (60), the yarn The thread accumulator means (4) is driven by its own electric actuation motor, the control means (60) is connected to the tension detection means (3) and the yarn accumulator means (4) and can The tension obtained by the measuring means (3) acts on the yarn accumulator (4), providing a compensator device (1), associated with the feeder device (2), in connection with the tension detection In cooperation with the yarn (F) leaving the yarn accumulator means (4) prior to the co-action of the means (3), the compensator device (1) can be in each first feed or take-up state with the successive The transition between each second feed or take-up state following the first feed or take-up state compensates for changes in the feed or take-up states of the yarn (F), thus allowing the feeder device to The control means (60) acts on the yarn accumulator means (4) to change its effect on the yarn, and maintain the tension value detected by the tension detection means (3) over time fixed and equal to a set value, the fixed tension is maintained even during the phases of changing the feeding states due to the interaction between the yarn and the compensator device (1) comprising movable compensating means capable of moving from a predetermined rest position along the feeding direction of the yarn (F) when the yarn is changed by the machine from a less wound state to a more wound state, but when the The yarn (F) moves in the opposite direction when changing from a larger winding state to a less winding state, the movable compensating means returns to the rest position at the end of the winding change, characterized in that the movable compensating means A rigid arm supporting a terminal body (16) capable of co-acting with the yarn (F) is directly and rigidly connected to its own electric motor (8), which according to the The set or detected tension of the yarn (F) directly controls the movement of the rigid arm, which is located between the yarn accumulator means (4) and the tension detection means (3), but not in relation to the tension The means of detection are separated. The system of claim 8, wherein optionally the rest position of the movable compensating means is located within a range of motion of the movable compensating means, the range of motion has two extreme positions, or is defined by the means relative to a In a circular path of the axis (M), the path has no angular limitation. A system as claimed in claim 8, wherein a position detector means (19) is provided to determine the spatial position of the rigid arm, the position detector means (19) being associated with the electric motor also rigidly supporting the rigid arm Drive shaft linkage. As the system of claim 10, wherein a control unit (60, 70) is provided for the electric motor (8) of the compensator device (1), the control unit is connected to the position detector means (19), And the movement of the movable compensating means from the predetermined rest position can be detected by the position detector means (19), and the movable compensating means can be made to move by controlling the electric motor to which the movable compensating means is rigidly and directly attached. means return to the predetermined rest position, the control unit (60, 70) is directly or indirectly connected to the yarn tension detection means (3), the control unit detects the The yarn (F) tension is used to control the electric motor. The system according to claim 11, wherein the control unit (60, 70) is selectively associated with the compensator device (1) and connected to the control means of the feeder device (2), or the control unit is the Part of the control means of the feeder unit (2). The system of claim 8, wherein the compensator device (1) is an independent component of the feeder device (2), the compensator device (1) is removably attached to the feeder device ( 2), and located at one end (2A) of the feeder device, or on one side, the compensator device (1) is fully automatic with respect to the feeder device (2), but when connected to the feeder device The feeder unit is tightly connected to the feeder unit. The system of claim 8, wherein the compensator device (1) has means (26) that rotate around its own axis and are capable of receiving the yarn (F) in at least one of the machine feed or take-up states when winding . A compensator device suitable for use in conjunction with a feeder device (2) for feeding a yarn (F) comprising metal threads or threads at a fixed tension to a textile machine (T) or to a textile machine (T) Metal wire processing machine, the feeder device (2) comprising tension detection means (3) for the yarn (F) and yarn accumulator means (4) for the yarn, the machine discontinuously Operation, the compensator device (1) and the feeder device (2) define a feeding system as claimed in claim 8, which operates according to the method of claim 1, the compensator device (1) has a movable compensation means, the The movable compensating means are capable of co-acting with the yarn (F) before it leaves the feeder device (2), characterized in that the movable compensating means are delimited by a rigid arm connected to actuating its The moving actuator means are rigidly associated, the rigid arm movably cooperating with the yarn (F) and the yarn accumulator means (4) located in the feeder device (2) and the tension detector Between the means (3), the tension detection means (3) is separated from the rigid arm and wherein the yarn accumulator means (4) is used for the yarn, the rigid arm can act as the yarn (F) by When the machine changes from a less coiled state to a larger coiled state, it moves along the yarn feeding direction from a predetermined rest position, but when the yarn changes from a larger coiled state to a less Moving in the opposite direction during the reeling state, a position detector means (19) is provided which can detect the movement away from the rest position, the position detector means (19) is connected to a control unit which can directly Or indirectly detect the tension of the yarn (F), and based on setting or detection Tension is used to control the actuator means to return the rigid arm to the rest position after movement from the rest position. A compensator device as claimed in claim 15, comprising rotating means (26) capable of receiving the yarn thereon when the machine is stopped, or during a stage of the yarn return feeding procedure.

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