GB2193978A - Yarn clearers - Google Patents

Abstract

In a yarn clearer, yarn 1 from a bobbin 2 passes through a monitor 3, sensor 10 and cutter 4, to a winder 5. When the monitor 3 senses a fault in the yarn 1, the knife 8 of the cutter 4 is activated, to cut the yarn 1, whereupon the yarn falls out of the sensor 10, which in turn sends a signal to a controller 11, to stop the winder 5. Sometimes, the cutter 4 can operate but fail to effect a cutting action. To prevent faulty yarn from being wound upon the winder 5, logic circuitry receives control signals from the yarn clearer. If the signals and denote that the yarn 1 is continuing to run past the sensor 10, a predetermined time after the cutter 4 has been activated, then a FAULT signal is emitted, and the winder is stopped. This indicates to an operator that the cutter 4 has been operated but unsuccessfully, and allows the operator to find and clear the fault, before restarting the yarn clearer. <IMAGE>

Description

SPECIFICATION Yarn clearers This invention relates to yarn clearers.

After spinning, yarns are commonly wound through clearers, to detect and remove faults.

These days, clearers are usually electronically controlled.

Typically, a clearer consists of a monitoring head, which continuously monitors the thickness of a yarn running along a path of travel, and a detector for detecting variations in the thickness monitored by the monitoring means.

A control device responds to the detector, and when an unacceptable variation in thickness is detected, the control device activates a solenoid operated cutter, to cut the yarn moving along its path of travel.

Thus, if a fault in the yarn is detected, then the yarn is cut. Normally, the clearer will also have a sensor for sensing the presence and/or motion of yarn along its path of travel, and providing a corresponding RUN signal to a yarn winder. Thus, when the yarn is cut, the RUN signal ceases, and this in turn causes the winder to stop operating.

The cut yarn ends are then rejoined, manually or automatically, and the fault removed at the same time. The winder is then restarted.

In practice, the cutter can fail to operate, for a number of reasons. For example, the movement of the cutter knife may be obstructed, perhaps because of dirt build-up, or there may be an obstruction on the anvil with which the cutter knife co-operates, to prevent the knife from cutting the yarn.

If the clearer detects a fault in the yarn, but the cutter fails to operate properly, then the yarn will continue running through the clearer, to be spooled by the winder. In such circumstances, instead of the fault being cleared, the yarn may be doubly faulty. Firstly, the original fault remains. Secondly, the yarn may be damaged by an incomplete cutting action.

The present invention aims to provide yarn clearers which may be improved in the foregoing respect.

According to a first aspect of the present invention, there is provided, for use with a yarn clearer which comprises: monitoring means for monitoring a para meter of a yarn running along a path of travel; detection means for detecting variations in said parameter monitored by the monitoring means; control means responsive to the detection means and operative to emit a CUT signal to a cutter means in the path of the yarn, in response to the detection means detecting a variation greater than a predetermined value; and sensing means for sensing yarn and opera tive to emit a RUN signal when sensing the presence and/or motion of yarn along its path of travel: fault indication means operative to receive both said CUT signal and said RUN signal and to emit a FAULT signal when said RUN signal is present a predetermined time after emission of said CUT signal.

The fault indication means may include alarm means which provides an audible and/or visible alarm upon emission of said fault signal.

Preferably, said fault indication means is substantially electronic.

The fault indication means may comprises timer means which is operative to emit a first pulse upon emission of said CUT signal and to emit a second pulse upon termination of said first pulse, and switching means which is operative to pass said second pulse to an output stage of the fault indication means, only when said RUN signal is present concurrently with said second pulse.

Said fault indiction means may be operative to latch into a FAULT condition upon emission of said FAULT signal, and comprise reset means for resetting the fault indication means.

In a second aspect, the invention provides a yarn clearer as aforesaid, provided with fault indication means in accordance with the first aspect of the invention. In such a yarn clearer, the monitoring means and sensing means may be constituted by a single device. Said parameter may be the thickness of a respective yarn.

The yarn clearer may include a cutter means as aforesaid, for cutting yarn, in response to the emission of said CUT signal.

The yarn clearer may be combined with winding means for winding yarn at the end of its path of travel, which winding means is responsive to said RUN signal. Such a winding means may be responsive also to said FAULT signal.

In a third aspect, the invention provides a method of modifying a yarn clearer, comprising the step of fitting to the yarn clearer a fault indication means in accordance with the first aspect of the present invention For a better understanding of the invention, and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: Figure 1 is a diagrammatic representation of a conventional yarn clearer; Figure 2 is a block schematic diagram of a yarn clearer embodying the present invention; and Figure 3 is a circuit diagram of one example of a fault detector.

In Fig. 1, yarn 1 from a bobbin 2 follows an upright path of travel through a monitor 3 and a cutter 4, to a winder 5, where the yarn 1 is spooled onto another bobbin, or suitablecar- rier.

The monitor 3 is operative, in a known manner, to monitor the thickness of the yarn 1 running through it, and to emit a signal pro portional to the thickness of the yarn, which signal is fed to a detector 6.

The detector 6 detects variations in the thickness of yarn, as monitored by the moni tor 3, and when a variation is detected which is greater than a predetermined limit value, then a corresponding control signal is passed to a control device 7, for the cutter 4. Upon receiving the control signal, the control device 7 activates a knife 8, to bear against an anvil 9, in order to cut the yarn 1 running there through.

A sensor 10 continually senses the pres ence and/or motion of yarn 1 along its path of travel, and emits an appropriate control sig nal to a controller 11, for the winder 5. Typi cally, the sensor 10 and monitor 3 are pro vided by the same physical device.

In use, the yarn 1 runs continuously through the monitor 3, sensor 10 and cutter 4, to be spooled by the winder 5. The sensor 10 con tinuously detects the motion of the yarn 1, and sends an appropriate RUN signal to the controller 11, to maintain the drive to the win der 5.

Upon the monitor 3 detecting a fault (e.g. a slubì in the yarn 1, an appropriate signal is generated by the detector 6 and fed to the control device 7, to cause the knife 8 to be urged towards the anvil 9 of the cutter 4, and thereby cut the yarn 1. The cut yarn then falls out from between the sensor 10 and monitor 3 The control signal from the sensor 10 changes, due to the loss of the yarn 1, and the controller 11 receives an appropriate con trol signal, to stop the drive of the winder 5.

As mentioned above, the yarn may be rejo; ined manually or automatically, removing the fault from the yarn 1, and the winder 5 re started.

In the block schematic diagram of Fig 2, there is represented by the reference numeral 20 an electronic clearer, which may be of a conventional nature, (e.g. as shown in Fig.1), the circuitry 20 being adapted to output two control signals X and Y. The CUT signal X corresponds to the output of the control de vice 7 of Fig. 1, and is in the form of a pulse, to operate the knife 8 of a respective cutter 4. The RUN signal Y corresponds to the out put of the sensor 10 of Fig. 1, and is a signal which is either continuously high or continu ously low, to be fed to the winder 5 or the controller 11 therefor.

The clearer of Fig. 2, howver, has additional circuitry, comprising a delay circuit 21, an AND gate 22, a latching relay-23, and an indicator 24.

In use, the RUN signal Y is usually continu ously high, indicating that yarn 1 is running through the clearer. In the event of a fault being detected in the yarn 1, the CUT signal appears as the signal X, which is fed to the cutter 4, to cut the yarn 1. The yarn 1 then drops out of the clearer, as described above, whereupon the signal Y immediately assumes a low value, the winer 5 is stopped, and the clearer awaits manual attention, to remove the fault.

However, in the event that the CUT signal at X results in an unsuccessful cutting operation, the RUN signal Y remains high, enabling the respective input of the AND gate 22.

Then, after a delay determined by the delay circuit 21, the CUT signal at X is passed to the other input of the AND gate 22, which thereupon passes the pulse through, to activate the relay 23. The relay 23 thereupon latches into a fault condition, and emits a signal to activate the fault indicator 25, which may comprise, for example, an audible and/or visible alarm. If desired, a signal may be passed from the fault indicator 24 to the winder 5 or controller 11 therefor, to ensure that the winder 5 is stopped.

Thus, when the fault indicator 24 is activated, the winder 5 is preferably stopped, and the machine minder can see that an abortive attempt has been made to remove a yarn fault. The minder then corrects the clearer fault, removes any yarn faults, and winding recommences. In order to do this, the minder has to activate a reset control R, on the latching relay 23.

Fig. 3 shows just one example of how the block diagram of Fig. 2 may be realised.

The signal X is applied at terminal E, which is connected via a low pass filter to a switching transistor T1.

When the CUT signal is present at X, the respective positive output pulse turns on the transistor T1, which in turn applies a corresponding negative going output pulse to an input pin 6 of a timer IC1.

The leading edge of the pulse applied to pin 6 of IC1 triggers a first pulse, which appears at pin 5 of IC1, and the trailing edge of which triggers a second pulse at pin 9 of It 1.

It will be appreciated that, in Fig. 3, various diodes, capacitor and resistors are shown, to provide the timer IC1 with the necessary biasing levels and timing intervals. The duration of the first pulse which appears at pin 5 constitutes a delay, which is set by the various component values, and following which the main output pulse of the timer IC1 is provided on pin 9.

This output pulse is fed from pin 9 via a switch contact SW1B, which is normally closed, to a SET coil RS1 of a relay R1.

Switch contact SW1B acts synchronously with a further switch contact SW1A, which is also normally closed. The relay R1 contains a first switching contact RS1 which is normally closed, a second switching contact RS2 which is normally open, and a RESET coil RC2, which is arranged in series with a RESET push button SW2, between earth and the low voltage +5 volts supply.

The first relay switching contact RS1 is disposed in series with the switch contact SW1A, between the winder 5 or controller 11 therefor, and a +24 volts supply. Thus, in normal operation, the +24 volts suppl.y is fed via the contact RS1 and switch SW1A to the winder 5, or controller 11 therefor, to maintain the winder 5 in operation.

The second relay switching contact RS2 is disposed in series with a light emitting diode LED1 and an appropriate resistance, between the +5 volt supply and ground.

When the output pulse from the timer IC1 is passed via the switch SW1B to the relay SET coil RC1, the relay R1 is energised, to cause the first relay contact RS1 to open, and the second relay contact RS2 to close. Thus, the +24 volt supply to the winder 5 is broken, causing the winder immediately to stop. At the same time, power is applied to the LED1, to indicate a fault condition.

It is to be understood that the position of the switches SW1A and SW1B represents the condition of the RUN signal Y, as depicted in Fig. 2. Thus, with the switches SW1A and SW1B in their closed positions, as shown, the RUN signal Y is high, indicating that the sensor 10 indicates yarn to be present and/or running therethrough. As soon as the yarn, or motion thereof, ceases to be sensed by the sensor 10, the switches SW1A and SW1B become opened. This corresponds to normal clearer action. The winder 5 is stopped, as the 24 volt control voltage is interrupted, by the switch SW1A. The delayed pulse from the timer 161 is not passed by the switch SW1B, to avoid setting of the relay R1.

Reverting now to the condition in which the relay 1 has been SET, as outlined above, the machine minder sees from the LED1 that a fault condition has arisen. The winder 5 has been stopped, and the minder can then rectify the fault, as mentioned above.

When this has been done and the ends rejoined, the minder simply presses the RESET button SW2, to energise the RESET coil RC2, and restore the relay switching contacts RS1 and RS2 to their normally closed and normally open positions, respectively.

The machine then resumes its normal operation.

Thus, there may be provided a clearer which has substantially electronic control circuitry, and is operative not only to carry out the normal clearer action, but also to cope with the situation whereupon the cutter 4 malfunctions. It will be appreciated that the illustrated circuity may be constructed and installed in a simple and reliable manner, and use thereof is likely to reduce the incidence of undetected faults, in the yarn being cleared.

The invention is not restricted to the details of the foregong embodiment(s). The invention exceeds to any novel one, or any novel combination, of the features disclosed in this specification and/or drawings, or to any novel one, or any novel combination, of the steps of any method or process disclosed herein.

Claims (13)

1. Fault indicator means for use with a yarn clearer which comprises: monitoring means for monitoring a para meter of a yarn running along a path of travel; detection means for detecting variations in said parameter monitored by the monitoring means; control means responsive to the detection means and operative to emit a CUT signal to a cutter means in the path of the yarn, in response to the detection means detecting a variation greater than a predetermined value; and sensing means for sensing yarn and opera tive to emit a RUN signal when sensing the presence and/or motion of yarn along its path of travel: the fault indication means being operative to receive both said CUT signal and said RUN signal and to emit a FAULT signal when said RUN signal is present a predetermined time after emission of said CUT signal.

2. Fault indication means according to Claim 1, including alarm means which provides an audible and/or visible alarm upon emission of said FAULT signal.

3. Fault indication means according to Claim 1 or 2, being substantially electronic.

4. Fault indication means according to Claim 1, 2 or 3, comprising timer means which is operative to emit a first pulse upon emission of said CUT signal and to emit a second pulse upon termination of said first pulse, and switching means which is operative to pass said second pulse to an output stage of the fault indication means, only when said RUN signal is present concurrently with said second pulse.

5. Fault indication means according to any of the preceding claims, operative to latch into a FAULT condition upon emission of said FAULT signal, and comprising reset means for resetting the fault indication means.

6. Fault indication means for use with a yarn clearer and substantially as hereinbefore described with reference to Fig. 1 and 2 of the accompanying drawings.

7. A yarn clearer as recited in Claim 1, provided with fault indication means in accordance with any of the preceding claims.

8. A yarn clearer according to Claim 7, wherein the monitoring means and sensing means are constituted by a single device.

9. A yarn clearer according to Claim 7 or 8, wherein said parameter is the thickness of a respective yarn.

10. A yarn clearer according to Claim 7, 8 or 9, including a cutter means as aforesaid, for cutting yarn, in response to the emission of said CUT signal.

11. A yarn clearer according to Claim 7, 8, 9 or 10, combined with winding means for winding yarn at the end of its path of travel, which winding means is responsive to said RUN signal.

12. A yarn clearer according to Claim 11, wherein said winding means is responsive also to said FAULT signal.

13. A method of modifying a yarn clearer, comprising the step of fitting to the yarn clearer a fault indication means in accordance with any of Claims 1 to 6.