JPH0432343B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Technical Field) The present invention relates to a yarn defect monitoring device used in yarn unevenness testers, electronic yarn clearers, etc. in the textile industry.

(Prior art) In general, in textile factories, for example, an electric capacitance type yarn defect monitoring device is used as a device to monitor yarn unevenness contained in yarn or yarn defects such as double yarn, thick yarn, thin yarn, etc. When a string inserted into a measuring capacitor consisting of a pair of flat metal plates runs through the capacitor, the electric capacitance of the measuring capacitor changes due to changes in dielectric constant due to changes in the weight of the string. This change in capacitance is electronically detected, and the weight fluctuation of the yarn is indirectly evaluated based on this change in capacitance.

In other words, this device uses the yarn's own dielectric constant as a standard, compares it with this dielectric constant, evaluates whether the dielectric constant of the yarn running inside the measurement capacitor is high or low, and detects yarn defects from this evaluation value. It is something.

Therefore, in an ideal state, the specific permittivity of a thread is determined by the material and count of the thread, so theoretically, it is possible to measure the permittivity of many threads made of the same material and with the same number. If the average value is set as the reference value for that yarn, yarn defects can be detected accurately, but in reality, when testing yarn that is not placed in ideal conditions or environments, The dielectric constant of the yarn varies depending on various factors such as the amount of moisture in the yarn and the presence or absence of fillers such as antistatic agents. needed to be corrected.

Therefore, a method was devised to determine the average permittivity of the yarn within a short period of time after the yarn is fed into the measurement section, and to detect yarn defects using this as a standard. Since a system is adopted in which multiple yarn defect monitoring devices installed in each winding machine are controlled by one control device, the reference value can be changed each time based on information from each yarn defect monitoring device. This resulted in the following disadvantages and was a practical problem.

In other words, if the sensitivity of the amplifier circuit in one of the multiple yarn defect monitor devices is low, if the reference value is changed to correct the amplification degree of this amplifier circuit, the sensitivity of all the other monitor devices becomes low. The sensitivity of the amplifier circuit increases, and conversely, if you modify the sensitivity of one highly sensitive amplifier circuit, the sensitivity of other amplifier circuits decreases, and the sensitivity of amplifier circuits other than the modified amplifier circuit changes. In addition to this drawback, even if all the amplifier circuits have the same sensitivity, if a yarn of a different count than the one set is mistakenly fed into one measuring circuit, it will naturally be detected as a defective yarn. The reference value was changed before this was detected, and there was a risk that the sensitivity of all other amplifier circuits would follow this reference value and malfunction.

(Object of the Invention) However, in order to eliminate and solve the above-mentioned drawbacks of the conventional device, the present invention improves the sensitivity of the amplifier circuits in the plurality of yarn defect monitoring devices in a system in which a plurality of yarn defect monitoring devices are controlled by one control device. A yarn defect monitoring device for individual correction is provided.

(Structure of the Invention) The yarn defect monitoring device according to the present invention includes a measuring circuit 2 that outputs a signal whose voltage changes according to weight fluctuations of the yarn passing through a measuring capacitor ₂₁ , and a measuring circuit 2 that amplifies the voltage change of this signal. In the yarn defect monitoring device 1, which is composed of an amplifier circuit 3 that outputs a signal U, the voltage of the signal U and a preset reference voltage are
A comparison circuit 4 that outputs a signal when there is a difference between Vm and Vm, and a control circuit 5 that adjusts the amplification degree of the amplifier circuit 3 based on the signal from the comparison circuit 4. It is. In addition, in the figure, A
is a central control device that supplies a reference voltage Vm corresponding to the dielectric constant determined by the yarn material and count to the yarn defect monitoring device 1...1.

(Operation of the Invention) Next, the operation of the apparatus of the present invention will be explained with reference to the illustrated embodiment according to the above configuration of the present invention.

That is, the power is turned on to the central control device A, and the reference voltage Vm corresponding to the setting of the material and count of the yarn to be tested is equally supplied to each yarn defect monitoring device 1. The sensitivity, that is, the amplification degree of the amplifier circuit 3 of each yarn defect monitoring device 1 is set by this reference voltage Vm, so when the yarn winding machine is driven and yarn is thrown into the measuring capacitor ₂₁ , this yarn feeding signal is transferred to the capacitor. Only the alternating current component is input to the amplifier circuit 3 through a high-pass filter constituted by C and a resistor R, and yarn defects are monitored starting from an input signal about one second after the yarn starts running. If the yarn is compatible with the set material and count, it is compatible with the amplification degree of the amplifier circuit 3, so that the amplifier circuit 3 outputs a signal with a voltage equal to the reference voltage Vm.

In other words, the running thread is monitored in this state,
If there is an abnormality, a signal U with a voltage different from the reference voltage Vm
is output, and if this voltage exceeds a tolerance value preset in a subsequent Schmitt circuit (not shown) or a built-in Schmitt circuit in the amplifier circuit 3, a command signal to cut or display is outputted.

After replacing or knotting the bobbin, a new thread is put into the measuring capacitor 2, and about one second after the thread starts running, the amplifier circuit 3 outputs a signal U that is below the allowable value (if it is above the allowable value, the thread is When a defect (detected as a defect) is output, this indicates that the dielectric constant of the input yarn is different from the set reference value, that is, there is a variation in the count. This output signal U is compared with the reference voltage Vm in the comparator circuit 4, and if there is a difference, a signal is output from the comparator circuit 4, and this signal is input to the control circuit 5.

Based on this input signal, the control circuit 5 outputs a control signal so that the signal from the comparison circuit 4 becomes zero, and corrects the sensitivity of the amplifier circuit 3. At the same time, the control signal is triggered and this state is fixed until a signal is received from the comparator circuit 4 due to yarn replacement or thread insertion after knotting.

That is, by the above control, the sensitivity of the amplifier circuit 3 is modified to match the actual yarn, and yarn defects are monitored.

Thereafter, the above-mentioned control is carried out every time the yarn is introduced to correct the sensitivity of the amplifier circuit 3 to match the actual yarn, and this sensitivity correction is performed independently by each yarn defect monitoring device.

(Effects of the Invention) As described above, according to the yarn defect monitor device according to the present invention, the quality of the yarn is compared with a preset reference value within a short period of time after the yarn is introduced into the measurement condenser. The average value is calculated, and the amplification degree of the amplifier circuit of each yarn defect monitoring device is adjusted independently to match this dielectric constant, so unlike conventional devices, the information of one yarn defect monitoring device is The above-mentioned disadvantages caused by changing the reference value and having its influence on all other devices are not present at all, and yarn defects can be monitored safely and reliably.

In this embodiment, an electric capacitance type yarn defect monitoring device was used, but the electric circuit of the present invention can also be applied to a photoelectric type or a sonic type device by selecting one suitable for each measurement head. It can be applied as is, and its action and effect are the same.

[Brief explanation of drawings]

The drawings illustrate embodiments of the present invention; FIG. 1 is a block diagram showing the state of controlling a plurality of yarn defect monitoring devices according to the present invention, and FIG. 2 is an electrical circuit diagram of the same device. 1... Yarn defect monitoring device, 2... Measuring circuit,
2...Measurement capacitor, 3...Amplification circuit, 4...
... Comparison circuit, 5 ... Control circuit, A ... Central control device, Vm ... Reference voltage, U (U ₁ , U ₂ ...) ...
detection signal.

Claims (1)

[Claims] 1 Measuring capacitor 2 Measuring circuit ₂ that outputs a signal whose voltage changes according to changes in physical quantities such as the weight of the thread passing through the measuring head such as 1, and an amplifier that amplifies the voltage change of this signal and outputs signal U In the yarn defect monitoring device 1 comprising a circuit 3,
A comparison circuit 4 that compares the voltage of the signal U and a preset reference voltage Vm and outputs a signal when there is a difference; and a control circuit that adjusts the amplification degree of the amplifier circuit 3 based on the signal from the comparison circuit 4. 5. A yarn defect monitoring device characterized by being provided with a.