INTERMINGLING DEVICE AND RELATIVE METHOD

Abstract

A thread intermingling device for textile machines includes a nozzle oriented to intercept the path of the base threads, a corresponding compressed-air feed line and intercepting means to intercept the line. The base threads are led next to the nozzle and impinged by a jet of compressed air causing intermingling. A control unit controls the intercepting means for shutting down the feed to the nozzle instantaneously or with delay with respect to the device stop and for reactivating the feed of compressed air to the nozzle instantaneously or in advance with respect to the device restart, and for the feedback automatic reactivation depending on the detected speed or movement of base threads.

Claims

1. A method for intermingling two or more base threads (4, 5), comprising the steps of: a) driving the base threads (4, 5) near a nozzle (6), feeding compressed air to the nozzle to achieve the intermingling, and accumulate the intermingled yarn (7) in windings (8) on an accumulating drum (9); b) detecting an amount of intermingled yarn (7) accumulated on the drum (9), and c) halting step a), by stopping the base threads (4, 5), when the amount of intermingled yarn (7) detected in step b) exceeds a threshold value, and d) restarting step a), when the amount of intermingled yarn (7) detected in step b) is below said threshold value, e) detecting a speed of the base threads (4, 5) or detecting whether the base threads (4, 5) are moving or not, f) shutting down the feed of compressed air to the nozzle (6) contemporaneously, or with a time delay (t), with respect to step c), and g) reactivating the feed of compressed air to the nozzle (6) contemporaneously, or with a time advance (t), with respect to step d), wherein steps f) and g) are feedback carried out on the basis of the detected speed of the base threads or depending on whether the base threads are still or moving, respectively, in order to avoid the wastage of compressed air and the jet too long impinging on the same portion of the base threads (4, 5), or the jet shutting down too early thus resulting in a un-intermingled portion of the yarn.

2. The method according to claim 1, wherein the delay and/or advance of steps f) and g) are adjustable.

3. The method according to claim 1, wherein at least one of steps c) and d), are carried out by providing for a gradual slowing down and acceleration, respectively, of the base threads (4, 5).

4. The method according to claim 3, wherein the slowing down and/or acceleration of the base threads (4, 5) follow corresponding deceleration and acceleration ramps.

5. The method according to claim 1, wherein step f) is carried out with a delay between 0 millisecond and 500 milliseconds with respect to step c) and/or wherein step g) is carried out with an advance between 0 millisecond and 500 milliseconds with respect to step d).

6. An intermingling device (1), for intermingling two or more base threads (4, 5), the device comprising: at least one electric motor (M), and at least one pulley (12, 13) and an accumulating drum (9) both rotated by the at least one electric motor (M), wherein the at least one pulley (12, 13) is for unwinding the base threads (4, 5) from respective spools (2, 3) and wherein the accumulating drum (9) is intended for receiving windings (8) of intermingled yarn (7), and comprising a nozzle (6) and a corresponding compressed-air feed line, wherein the base threads (4, 5) are led next to the nozzle (6) to be impinged by the respective jet of compressed air causing the intermingling, and comprising a detecting sensor (11) to detect to number of windings (8) of intermingled yarn (7) which are on the accumulating drum (9) and a control unit (ECU) programmed to feedback control the start and stop of the at least one electric motor (M) on the basis of the number of windings (8) said sensor (11) detected, further comprising detecting means (S1-S4) to detect a speed or movement of one or more base threads and intercepting means to intercept the compressed air, which are controlled by the control unit (ECU) for shutting down the feed of compressed air to the nozzle (6) contemporaneously, or with a time delay (t), with respect to the stop of the base threads (4, 5) and reactivating the feed of compressed air to the nozzle (6) contemporaneously, or with a time advance (t), with respect to time when the base threads actually restart moving, to compensate a changeable inertia of at least one of the spools (2, 3) when an amount of thread (4, 5) decreases and, at the same time, to avoid a wastage of compressed air or the jet too long impinging on the same portion of the base threads (4, 5), or a production of un-intermingled yarn length.

7. The intermingling device (1) according to claim 6, wherein the intercepting means comprise at least one electrovalve placed along the compressed-air feed line, upstream of the nozzle (6).

8. The intermingling device (1) according to claim 6, wherein the delay and/or advance in shutting down or reactivating, respectively, the feed of compressed air are adjustable in the control unit (ECU).

9. The intermingling device (1) according to claim 6, wherein the delay and/or advance are adjustable, respectively, between 0 millisecond and 500 milliseconds with respect to the stop and start of the at least one electric motor (M).

10. The intermingling device (1) according to claim 6, wherein the control unit (ECU) feedback controls the intercepting means of the compressed air on the basis of the number of windings (8) detected by said sensor (11), respectively in advance or delay with respect to the start and stop of the at least one electric motor (M).

11. The intermingling device (1) according to claim 6, further comprising an encoder or a speed transducer (15) arranged on a shaft of the at least one electric motor (M) to detect a rotation speed thereof, and wherein the control unit (ECU) feedback controls the intercepting means of the compressed air on the basis of the detected rotation speed.

12. The intermingling device (1) according to claim 6, further comprising permanent magnets (17) assembled on the accumulating drum or the pulley (12, 13) and a Hall sensor (16) arranged near the accumulating drum (9) or the at least one pulley (12, 13) to detect a rotation speed thereof, and wherein the control unit (ECU) feedback controls the intercepting means of the compressed air on the basis of the detected rotation speed.

13. The intermingling device (1) according to claim 6, further comprising movement sensors (18) arranged for detecting a movement of corresponding base threads (4, 5) and/or of the intermingled yarn (7), and wherein the control unit (ECU) feedback controls the intercepting means of the compressed air on the basis of a signal generated by said movement sensors (18).

14. The intermingling device (1) according to claim 6, further comprising a detecting circuit to detect the frequency of the signal sent by the control unit (ECU) to the at least one electric motor and to detect a current absorbed by the electric motor, and wherein the control unit feedback controls the intercepting means of the compressed air on the basis of the processing of said frequencies of absorbed current.

15. Use of the intermingling device (1) according to claim 6 to intermittently feed intermingled yarn (7) to a textile machine without wasting compressed air.

Description

BRIEF LIST OF THE FIGURES

[0071] Further characteristics and advantages of the invention will be more evident by the review of the following specification of a preferred, but not exclusive, embodiment, which is depicted for illustration purposes only and without limitation, with the aid of the attached drawings, in which:

[0072] FIG. 1 is a schematic and perspective view of a first embodiment of the intermingling device according to the present invention;

[0073] FIG. 2 is a schematic view of a second embodiment of the intermingling device according to the present invention;

[0074] FIG. 3 is a schematic view of a third embodiment of the intermingling device according to the present invention;

[0075] FIG. 4 is a schematic view of a fourth embodiment of the intermingling device according to the present invention;

[0076] FIG. 5 is frequencytime chart relating to the method according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0077] The following detailed description refers to an intermingling device 1 according to a first embodiment of the present invention. All components are housed on the body 1 of the device 1. The corresponding base threads 4 and 5 are withdrawn from two bobbins 2 and 3, for example a nylon base thread 4 and an elastomer base thread 5, which are conveniently guided by thread-guide eyes next to a nozzle 6 fed with compressed air by an outside line (not visible). As previously mentioned, the compressed air jet exiting from the nozzle 6 impinges the base threads 4 and 5 moving in front of the nozzle itself, and this causes the base threads 4 and 5 to be coupled at a plurality of intermingling points spread randomly on the length of the base threads itself. Downstream of the nozzle 6, in the movement direction of the base threads 4 and 5, a single intermingled yarn 7 is therefore obtained. The intermingled yarn 7 is wound in windings 8 on an accumulating drum 9. If necessary for the production cycle, the textile machine fed with the intermingled yarn 7 made by the device 1 withdraws an amount 10 of intermingled yarn from the accumulating drum 9, thereby reducing the number of windings 8 gathered thereon.

[0078] An appropriate sensor 11 detects the number of windings 8 being on the accumulating drum 9, with an adjustable sample frequency, for example from 1 time per second to 100 times per second.

[0079] An electronic control unit ECU provided with program means, installed in the body 1 of the device 1 as well, controls the functions of the device itself, as it will be described later.

[0080] An electrovalve (not shown) is provided along the feed line of compressed air, upstream of the nozzle 6 with respect to the flow direction. The electrovalve is driven by the control unit ECU.

[0081] In the body 1 there is also an electric motor M designed to be controlled by the ECU unit. In particular, the ECU unit drives the start of the electric motor M and the stop thereof on the basis of the number of windings 8 which are on the drum 9, in order to guarantee the supply of the intermingled yarn 7 to the textile machine downstream of the device 1, so that the thread 7 will be never missing, that would cause the down time of the textile machine.

[0082] In this first embodiment, the control unit ECU receives and processes the signal generated by the sensor 11, which can be for example an optic sensor, and operates as explained above, considering predetermined or adjustable threshold values of the number of windings 8 below which the electric motor M is restarted and above which the electric motor M is stopped.

[0083] In fact, the rollers 12 and 13, or pulleys, and the accumulating drum 9 are keyed to the shaft of the electric motor M. The roller 12 rotates the bobbin 3 to cause the unwinding of the thread 5, and the thread 4 winds on the roller 13 to form windings. Since the rollers 12 and 13 have different diameters, the base threads 4 and 5 are pulled with different strains, to obtain the desired drawing. The same result can be obtained by using two motors or by mounting rollers 12 and 13 with the same diameter which however rotate at different speeds, for example by using a reduction gear for one of the two rollers 12 or 13.

[0084] If one of the two base threads 4 or 5 has not to be drawn, one of the rollers 12 or 13 can be eliminated or is not fitted.

[0085] The accumulating drum 9 is preferably enclosed in a conical bell 14 rotating integrally with the drum 9 itself. The bell 14 is provided with a thread-guide bushing, at the rotation axis of the bell itself and the electric motor M, from which the portion 10 of intermingled yarn 7 comes out. Preferably, the bell 14 is removably constrained to the accumulating drum 9 by means of magnets.

[0086] With respect to conventional solutions, the device 1 differs in that the feed of compressed air to the nozzle 6 is not continuous, but it is shut down and reactivated in a controlled way subordinate to the real running of the yarns.

[0087] The device comprises at least one sensor among S1, S2, S3 or S4. For example, a sensor S1 is a movement sensor detecting the instant velocity of the thread 4, a sensor S2 is a movement sensor detecting the instant velocity of the thread 5, a sensor S3 is an encoder detecting the number of revolutions of the pulley 12, and a sensor S4 is an encoder detecting the number of revolutions of the shaft of the electric motor M. The sensors S1-S4 are connected to the control unit ECU, to which they send electric signals indicative of the detected speed.

[0088] By way of example, the sensors S1 and S2 can be movement sensors of the type marketed by BTSR company (www.btsr.com). Such sensors operate also as means driving the stop of the intermingler in case the yarn would break.

[0089] Referring to FIG. 5, a frequency-time chart is shown, aiding the comprehension of the just described concept. The sensor 11 is designed to send a binary signal to the control unit ECU; the signal can change between ON state, when the number of windings 8 on the drum 9 is low, and OFF state, when the number of windings 8 on the drum 9 is sufficient.

[0090] For example, let's consider the case in which the electric motor M is not running and the nozzle 6 is not fed. As time elapses (in abscissa), at a certain point the sensor 11 generates the ON signal (in ordinate) because it detects that the number of windings 8 of the intermingled yarn 7, which are on the accumulating drum 9, is lower than the threshold value. With a time advance t from 50 to 500 milliseconds with respect to the sending of the start signal to the electric motor M, the control unit ECU opens the electrovalve to reactivate the flow of compressed air to the nozzle 6. Straight after the electric motor M starts and accelerates up to reach the nominal rotation speed, in steady state condition.

[0091] As long as the electric motor M is running, the device 1 performs the intermingling of the base threads 4 and 5 and the produced intermingled yarn 7 accumulates on the accumulating drum 9 thus forming the windings 8. At one point the sensor 11 detects that the quantity of windings 8 wound on the accumulating drum 9 exceeded the predefined threshold values and generates the OFF signal. The control unit ECU immediately drives the switching off of the electric motor M, which reaches the completely stopped condition along a deceleration ramp. With a delay t from 50 to 500 milliseconds with respect to the stop of the electric motor M, the control unit ECU closes the electrovalve to shut down the flow of compressed air to the nozzle 6.

[0092] In the example shown in FIGS. 1 and 5, when the control unit ECU drives the motor stop, the latter slows down along a deceleration ramp lasting about 0.8 second. The motor M is provided with an inverter and when the output frequency falls below 3 Hz, direct current is entered by the inverter, which is instructed by the control unit ECU, in two of the phases of the electric motor M for about 0.5 second, and the motor M quite stops in position.

[0093] As explained above, in order to avoid the inertia of a great spool, such as the spool 3, from driving the pulley 12 and the shaft of the motor M therewith beyond the desired times, thus defeating the programming of the control unit ECU, the latter adapts automatically its operation on the basis of signals received from a sensor among S1-S4.

[0094] Preferably, the time advance t and the time delay t can be programmed inside the control unit ECU.

[0095] As it can be noted by the observation of FIG. 5, a shadowing time can be programmed, for example of 2 seconds, inside which the control unit does not intervene on the electric motor M even if the sensor 11 changes the signal. This serves for avoiding the shutting down of the compressed-air feed to the nozzle 6, when the switching off and the subsequent restart of the electric motor M are very temporally close, for example so close that the electric motor M has no time to stop completely before the restart thereof is driven.

[0096] FIGS. 2-4 show, only schematically, corresponding embodiments of an intermingler 1 according to the present invention.

[0097] In the example shown in FIG. 2, a rotary encoder 15 or a speed transducer is combined with the electric motor M (not shown for simplicity) and detects the number of revolutions of the shaft of the electric motor M. For example, the encoder has resolution of 50/100/200/500/1000 pls/rev. and is positioned directly on the shaft of the motor M. The control unit ECU acquires the signal provided by the encoder 15 to drive the motor itself and the electrovalve, as described above in connection with the first embodiment.

[0098] FIG. 3 shows an alternative in which the number of revolutions of the electric motor M is detected by using a Hall sensor 16 and a plurality of permanent magnets 17 mounted on board of the accumulating drum 9 or the respective bell 14, or else on board of the pulleys 12 or 13. The Hall sensor 16 detects the passage of the magnets 17 when the device 1 is operating and transmits a corresponding signal to the control unit ECU. The control unit ECU processes the signal provided by the Hall sensor 16 to drive the motor M itself and the electrovalve, as described above in connection with the first embodiment.

[0099] FIG. 4 shows an alternative in which the number of revolutions of the electric motor M is detected by using optic sensors 18 positioned along the path of the base threads 4 and 5. When the device 1 is operating, the sensors 18 transmit corresponding signals to the control unit ECU, which are indicative of the presence and the movement of the base threads 4 and 5. The control unit ECU processes these signals to drive the motor M itself and the electrovalve, as described above in connection with the first embodiment. Alternatively, a sensor 18 can be positioned along the path of the intermingled yarn 7 to detect the movement thereof.