GB2218117A - Monitoring an electromotor-operated textile machine unit - Google Patents

Description

2 '4 18 117 A method of monitoring an electromotor-operated textile

machine-unit -- This invention relates to a method of monitoring an electromotor-operated textile machine unit to detect a break in the thread.

Some known methods or means 'for monitoring electromotor-operated textile machines operate in dependence on the load and speed. This has the disadvantage inter alia that all spools must have the same weight and be operated at the same speed.

For example, DE-OS 29 46 031 describes a means for switching off an electromotor-operated single-spindle machine, the spindle being stopped by means of a differential circuit (not described) and a switching-off means, also not described.

According to the citation also, the thread feed is monitored or interrupted in conjunction with the switching-off means, and the roving is simultaneously removed by suction. The differential measuring element cooperates with a comparator which is individually set for this station. This means that each station inside the machine needs to have a separate reference voltage for the purpose of monitoring when there are different loads on the motors.

Another document, DE-OS 29 50 063, describes a monitoring circuit for detecting faults in the operation of a textile machine. As before, monitoring is possible only if all the electromotor-operated spindles are subjected to the same load and operated at the same speed. In addition. each motor requires individual adjustment. In this citation it is also assumed that the power required by the spindles varies continuously but also in synchronism. This, however, is incorrect. If, for example, the thread breaks, it is normal' for a number ofspindles to have a completely different cop weight from other spindles which are running without a thread break. The monitoring system described will not work in a situation of this kind, which situation cannot be excluded.

An aim of the present invention therefore is to avoid the aforementioned shortcomings and provide a monitoring system which reliably recognises a broken thread without interfering with the run of thread.

With this aim in view, the invention is directed to a method of monitoring an electromotor-operated textile machine unit to detect a break in the thread in which the electric power consumption of the motor is measured and compared with a preset value and, if the power consumption falls rapidly below a-set minimum value, a signal is given and switches off the textile machine unit.

The monitoring system according -to the invention assumes that the unit is driven by a single motor and is based on a switching-of f -threshold which reacts only to negative changes in current or voltage. The switchingvoltage threshold is adjusted so that a signal is given when the power consumption falls below a minimum value.

Y 1; If for example, the thread breaks in a twisting -or spinning spindle, the result of course being a rapid drop in power, the monitoring means reacts immediately and stops the spindle via a brake circuit. The break in the thread is-optically indicated, recorded and transfered to an evaluating computer. After the broken thread has been removed and the spindle restarted, the indication is automatically erased.

The switching-off threshold is adjusted separately for each unit so that the monitoring system operates completely independently of the permanent load and motor speed and of the adjacent spindles. This means that spindles with different loads of yarn and also rotating at different speeds can be monitored on a single machine. A twist spindle is shown here by way of example only. The monitoring system is of use in various textile machine units driven by a single motor, such as drawing rollers, wind-on machines, texturing spindles and the like.

An excess temperature switch and a special indicator are incorporated to deal with other kinds of faults, such as excess motor temperature, which are also separately recorded. This avoids a search f or a fault to check whether it is mechanical or to do with the yarns. The operator is immediately shown the cause of the fault. In the latter case also, the indication is erased when the motor restarts.

Some embodiments of the invention will now be described in detail, by way of example, with reference to the accompanying drawings, in which Figure 1 shows the twisting station of a draw twister comprising a twisting spindle, a galette unit and wind-on means; Figure 2 shows the galette drive as a side view of Figure 1; Figure 3 shows a covering station inside a covering machine comprising a feed spool, a covering spindle and wind-on means; Figure 4 shows a double-wire spindle; Figure 5 shows a flanged texturing spindle; and Figure 6 is a block circuit diagram of the monitoring system.

Figures 1 and 2 show a single twisting station inside a draw twister. A twisting spindle 1 is driven directly by a motor 2. It is monitored by monitoring means 3 connected via Rx to the motor 2. A thread y is supplied via a ring rail 4, a spinning ring 5 and a ring traveller 6 to a drawing galette 7. The drawing galette 7 is, as before, driven by the motor 2 (see Figure 2) which is monitored by the monitoring means 3. - A traversing roller 8 is used for drawing, after which the thread y is conveyed through a heater 9 to a delivery system. A delivery roller 10 is driven by the motor 2. Monitoring is via the monitoring means 3. The thread y travels via a pressure roller 11 to the wind-on means. As before, the wind-on roller 12 is driven by the motor 2 which is likewise monitored by the monitoring means 3. Thread y 1 1 9 L is then wound on a spool 13. All four motors are interconnected so that each fault is reported inside the twisting station of the individual unit which then.reacts by stopping.

Figure 3 shows a single covering station inside a covering machine. A thread x is conveyed f rom, a feed spool 14 through the hollow core of a covering spindle 15. The covering spindle 15 is directly driven by the motor 2 and monitored by the monitoring device 3 which is connected to the motor 2 by Rx. A thread y is supplied f rom a spool 16 to thread x and covers it, and then goes to the winding-on means. As before, a winding-on roller 17 is driven by the motor 2 which is monitored by means 3. winding-on occurs on a spool 18.

Figure 4 shows a double-wire twisting spindle 19 driven by the motor 2. As before, monitoring is via means 3 which are connected to the motor 2 via Rx.

Figure 5 shows a flanged texturing spindle 20. The motor 2 is incorporated in a casing 21 of a spindle 20 and is monitored by the device 3 which, as before, is connected to the motor 2 via Rx.

Figure 6 is a block circuit diagram of the monitoring means. The measuring resistors Rx are disposed in the line to the motor unit. During operation, a current I depending on the load flows through the resistors Rx. A voltage Ul is produced by the current I at resistor R. Transformer T transforms voltage U1 to a higher value. Since resistor R has a value of e.g. 0.27 ohms, so that there is no appreciable extra load, a current of 1A results in a voltage Ul of 0.27 V. The isolating transformer T transforms Ul up-wards for additional evaluation.

Components V1 and Cl are for rectifying and smoothing the signal.

V2 generates a voltage U3 which now varies in proportion to current I. V2 additionally amplifies U3 and isolates it from U4. Capacitor C2 decouples the dc component in the voltage U4 at the point P. At a supply voltage of US = 12 V, the voltage at point P, determined by the two equal resistances Rvl and Rv2, is US/2 = 6 V. The voltage US at point P changes only as a result of a rapid voltage rise or voltage drop through U4. Capacitor C2 lets rapid voltage changes through and becomes highly resistant when the voltage remains constant. The speed of reaction and consequently the sensitivity can be influenced via the value of Rvl, Rv2 and C. The electronic component V3 compares voltage US with voltage U6 and, at U7, produces a change in level if US f alls below U6. Since the change in voltage of US at point P by V2 or RvI and Rvi is dependent only on the voltage change of U4 and not on the absolute value of - U4, the limitingvalue setting of U6 remains valid irrespective of the value I of the motor current of the unit.

The monitoring electronic unit reacts only if there is a rapid negative change in U4, e.g. as a result of a broken thread. The change in level at U7 sets the store 4 1.

I'.- 1 1\ V4. The store component V4 indicates a broken thread via LED 1 until the unit is restarted by button S1 and the signal goes out. The brake relay K1 is actuated simultaneously with LED 1 via time stage V6 and supplies a braking voltage to the motor. After a time which can be set at V6, the braking relay K1 is switched of f and the unit restarts. When the unit stops, the braking relay K1 is likewise switched by button S1 via time stage V6. Each motor has an excess temperature switch S3. If the motor exceeds its maximum permitted temperature, S3 switches the store unit VS which, via LED 2, indicates the excess temperature of the motor. Simultaneously the motor - is slowed down by V4 coupled with V6 and K1. The motor excess temperature indicator does out when the unit restarts via S1.

When the unit starts, a positive peak occurs at point P. The monitoring electronic unit is actuated by the start signal via a timing element, but only after the running-up phase. The running-up phase of the motor has no influence on the monitoring electronic unit.- A percentage switching-off threshold for each station can be adjusted via the central pentiometer R centrally for each station by means of an adjustable lower threshold voltage.

Claims (7)

Claims

1. A method of monitoring an electromotor-operated textile machine unit to detect a break in the thread in which the electric power consumption of the motor is measured and compared with a preset value and,, if the power consumption falls rapidly below a sbt minimum value,a signal is given and switches off the textile machine unit.

2. A method of monitoring an electromotor-operated textile machine unit according to claim 1, in which switching-off occurs only if there are negative changes in current or voltage.

3. A method of monitoring an electromotor-operated textile machine unit according to claim 1, in which I switching-off is brought about only via a voltage quantity which -is adjustable via potentiometers, and for all motors in the case of multi- spindle machines.

4. A method of monitoring an electromotor-operated textile machine unit according to claim 1, in which the stoppage of the textile machine unit is registered by data acquisition means and an evaluation is simultaneously made.

5.. A method of monitoring an electromotor-operated textile machine unit according to claim 1 substantially as described herein with reference to any figure in the accompanying drawings.

6. An electromotor-operated textile machine unit adapted to operate by the method of claim 1.

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7. An electromotor-operated textile machine must substantially as' described herein with reference to any figure in the accompanying drawings.

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Published 1989atThe Patent Office, State House. 66"71 High HcCmrn, LondonVTC;lR4TP. Further copies maybe obtainedfrom The Patent Office, Sales Branch, St Mary Cray, Orpington. Kent BR5 3RD. Printed by Mjltiplex techniques ltd, St Mary Cray. Kent, Con. 1/87 Sales Branch, St Mary Cray, Orpington. Kent BR5 3AD. Printed Dy JZjJtlplex tecPnIqueS ita, m zaary uray. Aem. uaii. vo r