SU1756408A1 - Device to control tension of moving fiber - Google Patents

Abstract

The invention relates to the production of fibers, yarn and threads in the textile industry and is intended to control the tension of yarns, fibers, yarn and other products. The device comprises a housing 1, thread conductors 2-4, a displacement sensor 5, chokes 8 and 17, a generator 18, an AC amplifier 19, a rectifier 20, a DC amplifier 21 with an installation block 22 0, an analog-to-digital converter 23, a digital indicator . The displacement sensor of the measuring conductor is made in the form of a bridge circuit with an open U-shaped core installed in one of the arms of the throttle, the plane of which is perpendicular to the common plane of the guide wire guides and which is housed in the housing for movement of the measuring wire conductor. The gap between the plane of the pole pieces of the U-shaped core and the surface of the measuring conductor is 0.05-0.2 of the maximum cross-sectional size of the pole piece. The load is placed on the balancing rod with the ability to move along it and fix it. 3 il. Yu (L S

Description

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The invention relates to the production of fibers, yarn, and filaments and is intended to control technological processes in the textile industry.

A device for controlling the thread tension is known, comprising a housing, a lever, a probe connected to the lever, and a force transducer.

The disadvantages of this device are the dependence of the readings on the orientation of the device in space, the greater sensitivity to the vibration of the base due to the imbalance of the lever with the cover around the axis of rotation, a significant error from nonlinearity due to the need to ensure the movement of the lever to act on the sensitive element. These deficiencies lead to a narrowing of the field of use of the known device in the textile industry.

The closest in technical essence to the present invention is an instrument for measuring the tension of a moving thread, comprising a body connected to. They have two parallel guide rods and a measuring rod placed at equal distances between them. The rods are provided with thread conductors, the measuring rod is connected with the body with the possibility of elastic rotation around the axis, perpendicular to the rod, the sensor moving the measuring rod, a DC amplifier, a power source and an indicator.

The disadvantages of the known device are, firstly, a significant error from non-linearity, which is due to a change in the angle of coverage of the thread of the measuring rod due to the displacement of the latter by the action of a force. The displacement of the rod is significantly due to the use of a strain gauge sensor, the operation of which requires high voltages (10–20 kgf / mm2) in the area of the strain gauges. which leads to the movement of the rod end up to several millimeters. In addition to changing the angle of coverage of the thread, there is another reason for non-linearity: large displacements of the end of the measuring rod result in non-linearity of the measuring rod itself, as an elastic tensometric element. The second cause of the error is the dependence of the device readings on the position in space due to the imbalance of the measuring rod around the axis of rotation. Therefore, it is necessary to limit and normalize the change in the position of the device in space during calibration and subsequent

application. If, when calibrated in a laboratory, this requirement is doable, albeit with difficulty, it can be done in rare cases when moving from a laboratory to a workshop. In addition, changes in the orientation of the known device in space during operation are unacceptable so as not to knock down the graduation, and this is practically impossible under shop conditions. The total error, caused by & these two reasons, reaches tens of percent, which limits the scope of the device to control only one, once and for all, tension, and switching from one value of controlled tension to another or switching to another machine requires significant readjustment. and a new graduation of the known device.

The known device also introduces, due to the imbalance of the measuring rod and its large displacement, a significant error if a dynamic component is imposed on the static tension, for example, from the support vibration, which further narrows the area of use of the prototype.

The purpose of the invention is to improve the accuracy of tension control.

Expanding the scope, i.e. Providing the ability to control the tension of threads on many types of machines, at different levels of tension on the thread, at different orientations of the device in space and in the presence of vibration of the base, makes it possible to approach the thread with the device in the case of tight spaces, which is often required when checking conditions of actual operation. The ability to control the tension in the dynamics also broadens the field of application. This makes it possible to control it with significant shaking of the operator's hand holding the device by the case, or during the vibrations of the support to which the device case is attached.

The goal is achieved by introducing an AC amplifier, a generator, a rectifier, an analog-to-digital converter, a balancing rod and a load, a DC amplifier with two inputs, a displacement sensor in the form of throttles with an open U-shaped core, whose plane is perpendicular to the common plane of the guide rods, and placed in the housing with the possibility of movement and fixation in the direction of movement of the measuring rod so that the gap between the plane and the field The tips of the U-shaped core and the surface of the measuring rod are 0.05-0.20 of the maximum cross-sectional size of the pole piece, the balancing rod is rigidly connected to the measuring rod and located in the housing on the other side of the axis of elastic rotation of the measuring rod, the load is placed on the balancing rod. the rod can be moved along it and locked, the choke is connected to the generator output and to the input of the AC amplifier, the output of which is connected to the rectifier input, the output of A ripper is connected to the input of a DC amplifier, the output of a DC amplifier is connected to the input of an analog-digital converter, the output of which is connected to an indicator.

FIG. 1 shows a block diagram of the device; in fig. 2 shows a general electromechanical scheme of the device, a cut, side view; in fig. 3 shows the wiring of the thread in the thread conductors in conjunction with the force addition scheme.

The device consists of a housing 1, to which two parallel guides of conductor 2 and 3 are connected and a measuring conductor 4 placed in equal distance between them at equal distances 4. The latter is connected with housing 1 with the possibility of elastic rotation around the axis of rotation 6. The possibility of elastic rotation can be provided in several ways: the usual sliding bearing or ball on the axis 6, the spring 7, connecting the measuring thread conductor nikz with the housing 1 at some distance from the axis 6, either by inserting torsion springs coaxially with the axis 6, or using elastic elements of torsion or bending type instead of axis 6, etc. What is essential in this case is only the provision of rotation of the measuring thread conductor 4 around the axis G with the occurrence when the elastic reactive moment of resistance is rotated. The movement of the measuring conductor A under the action of the load P is converted into an electrical signal by the displacement sensor 5, made in the form of a bridge circuit, in one of the arms an choke 8 with an open U-shaped core 9 and a winding 10 is turned on. The plane of the U-shaped core 3 is perpendicular the common plane of the thread guides 2-4. The core 9 is placed in the housing 1 with the possibility of moving in the direction perpendicular to the thread guide, 3 and fixing in the selected direction (in FIG. 2, up and down direction) using, for example, screws 11, which allows

adjust the initial gap 60 between the plane of the 12 pole tips of the core 9 and the measuring thread guide 3. The thread guide 4 can be made

from ferromagnetic material, for example steel, if, for reasons of weight reduction, it is made of light non-magnetic alloys, then in the zone where core 9 is placed to the conductor A

attach a ferromagnetic alloy plate (not shown). Inside the case, a balancing rod 13 is rigidly attached to the measuring thread, the water guide 4, on which the balancing weight 14 is placed with the possibility of moving along the rods and fixing on it when adjusting the device. Resistor 15, adjustable resistor 16, choke 8 and additional choke 17 form a bridge circuit powered by a generator 18. From the output diagonal of the bridge circuit, the signal arrives at the input of the AC amplifier 19, the output of the amplifier goes to the rectifier 20, rectifier

the signal is fed to the first input of the DC amplifier 21, the second input of the amplifier 21 is supplied with a signal from the zero setting unit 22. The signal from the DC amplifier 21 is fed to the analog-to-digital converter 23 and from it to the digital display indicator 24. All electrical components of the device, including a battery power source (not shown), are located in the housing 1.

Thread 25 is skipped with a kink, corresponding to the angle and its rotation when passing through the thread guides 2. This angle is determined by the initial position of the thread guides 2 and 3.

The device works as follows.

The tension T of the thread 25 causes, in accordance with the rule of the parallelogram of the addition of forces, the appearance of the force P acting

on the measuring thread 4 and causing it to move so that the gap between the plane 12 and the surface of the thread guide 4 is reduced. This causes a change in the inductive resistance.

the throttle 18 of the displacement sensor 5 and the change in the output signal of the AC amplifier 19, the signal of which is rectified by the rectifier 20 and fed to the DC amplifier 21. Without

The threads in the thread conductors 3 and 4 at the input of the DC amplifier can be the initial signal that needs to be compensated. This task is accomplished by the zero-setting unit 22, which produces a signal that compensates for the initial signal from the rectifier 20. Compensation can be made by the hand-setter or automatically. The signal from the amplifier 21 DC is fed to the analog-to-digital converter 23, and from it to the digital display 24.

Devices of this type have inherent errors from non-linearity and from changes in orientation in space. The error of nonlinearity arises due to a decrease in the angle of rotation of the filament around the subconductor 3 when the measuring conductor 4 moves under the action of the force P. At the same time, due to the decrease in the angle a, the tension conversion factor T to the force P equal to 2slna decreases, which leads to reduce the sensitivity of the device with an increase in the force T, i.e. to the nonlinearity of the conversion characteristic. To compensate for this error, an adjustment of the gap between the plane 10 and the measuring conductor 3 is used. As this gap decreases, the sensitivity of the movement sensor 5 to the movement change increases, which makes it possible to compensate for the error of nonlinearity when these characteristics are multiplied by successive conversion.

By filming this in more detail. The proposed device in the electromechanical part implements the following chain of successive transformations:

.

The nonlinearity in the first link of T to P has the same character as the nonlinearity in the link P to g - the change in the distance between the plane 12 and the conductor 4. Since the successive transformations transform the multiplication coefficients, the nonlinearity of the T to b conversion will have the same character - the convexity upwards and the transformation characteristic of the second link of the chain are not shown in the drawings. The third conversion link in U has a different character of the nonlinearity of the conversion characteristic — convexity downwards, and multiplying these characteristics, performed by sequential conversion, can, subject to certain initial conditions, compensate for the nonlinearity of the entire path.

It was established experimentally that, in order to compensate for the error

from nonlinearity it is necessary that the initial gap between the plane of the pole tips of the U-shaped core and the surface of the measuring rod

was 0.05-0.20 maximum cross-sectional size of the pole piece.

To ensure the possibility of compensating for the error of non-linearity also

it is necessary to ensure the displacement of the initial potential at the output diagonal of the bridge in order to best align the curvature of the conversion characteristic to the links x T P and the curvature of the conversion characteristic of the link. For this purpose, bridge resistor 16 is adjustable. By changing its resistance, it is possible to ensure the displacement of the initial potential of the output diagonal of the bridge towards

decrease and increase, and with the indicated restrictions on the ratio of the cross section of the pole piece and the original gap between the plane of the pole pieces and the surface of the measuring rod, always ensure that the curvature of the multiplied conversion characteristics is matched to reduce the error from nonlinearity to any predetermined

level

To compensate for the error of orientation change, the balancing rod 13 with the load 14 serves. Moving the load 14 along the rod, one achieves

when the body turns without a thread, the indicator 24 does not change, i.e. so that the moment from load 14 relative to axis 6 compensates the moment from the outer part of the thread conductor 4.

The compensation of static moments about the axis b, realizable when balancing with the help of load 14, not only makes the device independent of orientation in space, but also improves the dynamic

measurement If the base on which the device case is mounted or the operator's hand is shaking, these vibrations are in the nature of translational movements, while the inertia forces of the thread conductor 4 are balanced on the one hand by the inertia of the rod 13 and the load 14 on the other hand, which reduces the dynamic error.

Improving accuracy by reducing the error of nonlinearity allows the device to be used in a wide range of loads for relatively thick threads with high tension, when the device operates at the end of the scale,

and for relatively thin yarns with good tension when the device is at the beginning of the scale. This greatly expands the field of application of the device. Reducing the error of orientation changes and dynamic effects allows the device to be used to measure vibrating, i.e. working in operating modes, machines, and the accuracy is almost the same as when measuring on fixed threads, and measure the tension in hard-to-reach places, when for approaching the thread it is necessary to change the orientation of the device in space. It also greatly expands the field of application of the device.

Claims (1)

Claims An apparatus for monitoring the tension of a moving yarn, comprising a housing with two parallel guide conductors and a measuring thread guide arranged in parallel between them at equal distances. installed with the possibility of elastic rotation around the axis. perpendicular to the conductors, the displacement sensor of the measuring conductor. DC amplifier, indicator, characterized in that. In order to increase the accuracy of the control, it contains a generator, a rectifier, a zero setting unit, an AC amplifier, an analog-to-digital converter, a balancing rod and load, a measuring sensor The thread guide is made in the form of a bridge circuit with a choke with an open U-shaped core installed in one of the arms, the plane of which is perpendicular to the common plane of the guides thread guides. placed in the housing with the possibility of moving the measuring thread conductor as follows. that the gap between the plane of the polar tips of the U-shaped core and the surface of the measuring conductor is 0.05-0.2 of the maximum cross-sectional size of the pole tip, the balancing rod is located in the housing on the other side of the elastic axis rotation of the measuring thread conductor, rigidly connected with it, the load is placed on the balancing rod with the ability to move along it and fixation, the generator output is connected to the pavement a circuit in the diagonal of which an AC amplifier is connected, connected via a series-connected rectifier, a DC amplifier, an analog-to-digital converter with an indicator, and the zero setting unit is connected to the second input of the dc amplifier.