EP0445489B1 - Weft measuring device for a loom - Google Patents

Description

The invention relates to a metering device for the weft thread of a weaving machine with a metering roller, which lies between a supply unit and a take-off unit and which is wound around the weft thread in metering operation and determines the pulling speed of the weft thread. Metering devices and thread take-off devices for weft threads have long been used in various types of weaving machines. For example, DE-A-25 45 476 shows a device for delivering yarn to a weaving machine, which has a metering roller for the pulling-off speed of the weft thread and a downstream thread store. FR-A-2 190 962 shows a metering device which, in addition to the device according to DE-A-25 45 476, has a shooting nozzle and a catching nozzle on a shooting axis which is parallel to a tangent but in one plane in a plane approximately perpendicular to the roll axis of the metering roll Minimum distance the metering roller crosses.

Interruptions in the weaving process due to bobbin changes or weft breakage cause unpleasant losses in weaving time. The invention takes this fact into account. On the one hand, it has the task of automatically feeding new spools or interruptions in the weft, and inevitably a new weft into one for weaving to bring the intended starting position, as well as to deliver the weft to the weaving machine in a coordinated manner.

According to the invention, this object is achieved in that a catch nose is installed near the circumferential surface of the metering roller and can be rotated in a controlled manner about the roller axis, and in that the weft thread enters a catch area of the catch nose via a controlled relative movement between a weft thread lying in the insertion axis and the catch nose is displaceable with the purpose of wrapping the metering roll with a certain number of turns.

The advantage of the invention is that a higher availability of the weaving machine arises when certain types of interruptions in the weft thread are automatically remedied when they arise or at the command of the operating personnel. The dependent claims 2 to 17 relate to advantageous developments of the invention, while in independent claim 18 the use of the invention in row shed looms is claimed as an advantage.

Fig. 1

Eine schematische Anordnung von mechanischen Elementen einer erfindungsgemässen Zumesseinrichtung mit eingeschossenem Faden und mit noch nicht umwickelter Zumessrolle;

Fig. 2

eine weitere schematische Anordnung von mechanischen Elementen einer Zumesseinrichtung mit eingeschossenem Faden und mit noch nicht umwickelter Zumessrolle;

Fig. 3

eine einschwenkbare Vorratsspule mit einem zur Uebergabe präparierten Fadenanfang;

Fig. 4

die Ansicht einer Zumessrolle in einer Vorrichtung nach Fig. 1 mit der Auslenkung des eingeschossenen Fadens mittels Luftstrahl;

Fig. 5

die Ansicht einer Zumessrolle in einer Vorrichtung nach Fig. 1 mit der Auslenkung eines eingeschossenen Fadens mittels schwenkbarer Oese;

Fig. 6

den Schnitt durch eine Zumessrolle gemäss der Anordnung nach Fig. 5;

Fig. 7

den Schnitt durch eine Zumessrolle gemäss Fig. 5, jedoch mit konischer Mantelfläche der Zumessrolle;

Fig. 8

den Schnitt durch eine Zumessrolle in einer Vorrichtung gemäss Fig. 2 mit einem eingefahrenen Flyerhaken;

Fig. 9

die geschnittene Ansicht einer Zumessrolle entsprechend der Anordnung nach Fig. 1 mit der Geometrie für einen Stift im Rand der Zumessrolle, und

Fig. 10

ein Schema der Hierarchie der Maschinensteuerung mit Zuordnung von Sensoren und Stellelementen, die im Zusammenhang mit der Zumessvorrichtung stehen.

The invention is described below using exemplary embodiments. Show it:

Fig. 1

A schematic arrangement of mechanical elements of a metering device according to the invention with a thread inserted and with a metering roller not yet wrapped;

Fig. 2

another schematic arrangement of mechanical elements of a metering device with an inserted thread and with a metering roll not yet wrapped;

Fig. 3

a pivoting supply spool with a thread beginning prepared for transfer;

Fig. 4

the view of a metering roller in a device according to Figure 1 with the deflection of the injected thread by means of an air jet.

Fig. 5

the view of a metering roller in a device according to Figure 1 with the deflection of a thread inserted by means of a pivotable eyelet.

Fig. 6

the section through a metering roller according to the arrangement of FIG. 5;

Fig. 7

the section through a metering roller according to FIG 5, but with a conical outer surface of the metering roller.

Fig. 8

the section through a metering roller in a device according to Figure 2 with a retracted flyer hook.

Fig. 9

the sectional view of a metering roller according to the arrangement of FIG. 1 with the geometry for a pin in the edge of the metering roller, and

Fig. 10

a diagram of the hierarchy of the machine control with assignment of sensors and actuators that are related to the metering device.

In the figures, metering devices 1 for the weft thread 2 of a weaving machine are shown. In metering operation, a multiply wrapped metering roller 3, which lies between a supply unit 10 and a take-off unit 20, determines the pull-off speed of the weft thread 2, the rotational movement of the metering roller being matched to the weaving cycle. If the weft thread is interrupted, sensors respond, e.g. in the event of an interruption in the metering area, the sensors 35 and / or 51 and give a signal to a controller 33 which, on the one hand, stops the weaving machine, frees it from thread remnants and brings it into a starting position, and, on the other hand, automatically threading a weft thread 2 into one Start position causes. With the threading of the weft thread 2, the multiple wrapping of the metering roller 3 and the transfer of a thread start to a weft preparation 50 are linked by the control 33.

In metering mode, the weft thread 2 is drawn off from a supply spool 38 and, viewed in the conveying direction, runs over an eyelet 37, through a suction nozzle 14, through a brake 12, past a sensor 35 for thread interruption, through a shooting nozzle 11 on a metering roller 3. After several passes on the metering roller 3, the thread 2 runs through a catch nozzle 21 and pulling element 24, past a sensor 51 for thread interruption into a transport nozzle 52 of the weft preparation 50. The suction nozzle 14, the shooting nozzle 11, and separating elements 25 and which can be pivoted into the thread path Deflection devices 22, which are located between pulling element 24 and transport nozzle 52, are not activated. The weft thread 2 is braked on the brake 12 with an adjustable force and runs under tension on the metering roller 3. A pull-off element 24 shows a nozzle which exerts so much tension on the weft thread 2 that the rope friction in the winding direction 41 rotating metering roller 3 is sufficient to convey the thread at a certain peripheral speed against the pulling reaction force and against the friction in the elements between the supply spool 38 and metering roller 3. In order to prevent the thread running from the metering roller 3 from being unwound, its outer surface is designed as a conical outer surface 32 as in FIG. 7 or, as in FIGS. 2, 4, 5, 6, 8, 9, by a guide pin 30 which is directed toward the roller axis 5 has an angle <7 °, supported.

The sequence for automated threading is first described using the arrangement according to FIG. 1.

With the signals for thread interruption in the sensor 51 and thread interruption in the sensor 35, it is initially assumed that the thread 2 is broken in or behind the brake 12 in the thread running direction. A pneumatically operated deflection device 22 moves in front of the sensor 51 into the thread travel path. The thread paths that lie behind the brake 12 in the running direction are blown out. The metering roller, which is driven in its roller axis 5 by a rotary motor 17, which is combined with an angle encoder 18 as position detection, moves in the direction of rotation 41 until a catch 6 from the edge 28 of the metering roller 3 closest to a shooting axis 4 in the starting position stands. With a shooting command, the brake 12 is opened pneumatically and the suction nozzle 14, the shooting nozzle 11 and the catching nozzle 21 with the pulling element 24 are actuated for predetermined time intervals in order to pass the beginning of the thread caused by the thread break along the shooting axis 4 from the suction nozzle 14 to the shooting nozzle 11, past the To shoot the outer surface of the metering roller to the catch nozzle 21 and further via the pulling element 24, which consists of a nozzle extension, into the deflection device 22. If, as previously assumed, there is still thread in the suction nozzle 14, the sensor 35 now indicates the presence of thread.

If the sensor 35 does not display any thread at this time, it must be assumed that the thread has run out and that the supply spool 38 needs to be changed. For this purpose, the shoot-in command is first reversed and then the old supply spool 38 is pivoted away about a pivot axis 58 by a pivoting device 53, as can be seen in FIG. 3, and a new supply spool 38 is pivoted toward the suction nozzle 14 on a pivoting arm 59. The swivel arm 59 extends laterally past the supply spool 38 in order to limit the pull-off balloon, and ends once in an eyelet 37 through which the thread start 15 of the new supply spool is guided and on the other hand in a weakly acting thread clamp 19 which prevents the overhanging Thread beginning 15 parallel to a slot 13 of the suction nozzle 14 for suction and shooting. With the completion of the bobbin change, the previous insertion command is reactivated and the insertion takes place, as previously described, into the deflection device 22, the sensor 35 having to confirm the presence of the thread.

The shooting-in axis 4 lies approximately in a plane perpendicular to the roller axis 5 and at a minimum distance from the lateral surface of the metering roller 3. The minimum distance from the lateral surface is so large that the air jet of the injection nozzle 11 is deflected only insignificantly by the curvature of the lateral surface.

In the deflection device 22, the air flow and weft thread 26 are deflected to a thread store 23 until the brake 12 closes, while the catch nozzle 21 with the pulling element 24 remains exposed to air. There is no further thread transport because the braking force of Brake 12 is stronger than the pulling force of pulling element 24. A deflection element 9 now executes a rotary movement in the vicinity of the catch 6 and moves an edge 7 of a pin arranged transversely to the insertion axis 4 into the insertion axis 4 and deflects the weft thread 2 further into a catching region 8 with a controlled relative movement 40 the catch nose 6. The metering roller 3 is rotated by the rotary motor 17 through a whole number of turns in the winding direction 41 and at the start of each turn the catch nose 6 crosses the deflected weft thread 2 in its catch area 8 and takes it in the form of a loop. The weft thread 2 is taken along by the catch 6 against the pulling action of the pulling element 24, the thread being pulled backwards out of the thread store 23 until the rope friction on the metering roller 3 is sufficient to pull the thread through the brake 12 from the supply spool 38 deduct. Each time the catch nose 6 approaches the shooting axis 4 during its revolutions with the retracted thread loop, the thread drawn on the front side of the metering roller 3 by the catch nozzle 21 jumps back over the edge 28 of the metering roller onto its outer surface.

So that this springing back of the thread also works in arrangements which have a guide pin 30 between the shooting axis 4 and the metering roller 3, the edge 28 of the metering roller is provided with an overlap 48, under which the guide pin is immersed, as shown in FIGS. 6 and 9. In Fig. 9, the guide pin is additionally provided with a stop 49 which prevents the weft thread from slipping off.

If the revolutions continue beyond the starting position of the catch 6, the weft thread is caught again each time by the catch 6 the deflection element 9 is actuated. The wrapping movements of the metering roller 3 are interrupted in the starting position of the catch 6 and the deflection element 9 swings back into its starting position and releases the thread running to the catch nozzle 21. The metering roll is wrapped and the weft thread is tensioned into the thread store 23. By cutting the weft thread with a separating element 25 behind the pulling element 24, a new weft thread tip is generated, the position of which is given by the location of the separating element 25. The cut end of the thread disappears in the thread store 23 and the deflection device 22 moves back into its starting position and clears the way to the transport nozzle 52. The new weft thread tip is brought into a starting position for the next weaving cycle by a targeted rotation of the metering roller 3 by a predetermined angle, the presence of the weft thread having to be confirmed by the sensor 51.

An air deflection element 39 is shown in FIG. 4 as a further deflection element, which deflects the weft thread 2 in the form of an arc from the insertion axis 4 into the catch area 8 of the catch nose 6.

5, 6 and 7, a pivotable eyelet 36 is shown with a rest position in the insertion axis, through which the weft thread is also inserted and which swings the weft thread from the insertion axis 4 into the catch area 8 of the catch nose 6.

In Fig. 9, a continuous edge 28 of the metering roller 3 is shown, in which a pin 46 is inserted as a catch 6, which forms with its axis an angle with the vertical of its base 47 on the roller axis 5, which is less than 60 °. Part of the slope of pin 46 is in the wrap direction 41 to secure the thread to be able to take over. In contrast to a catch 6, which is formed by a recess in the edge 28 of the metering roller, the imbalance is smaller, the mass of the pin is easier to ascertain and the imbalance can be easily compensated for high metering speeds.

2 and 8 show a modified system for generating a relative movement 40 between the weft thread 2 in the weft axis 4 and a catch nose which is designed as a flyer hook 29 which also rotates at times and which is plugged onto the metering roller 3 for wrapping and with the wrapping Crossing axis crosses. Instead of moving the weft into a catch area, the catch area is moved to the weft. For this purpose, a holder 31, which is positively rounded toward the edge of the metering roller 3, is axially immersed in the metering roller 3 and anchored with permanent magnets 43 by adhesive action. The magnetic flux is bundled in the holder 31 by pole bridges 44 and in the metering roller 3 by a soft iron ring 42. The flyer hook 29 moves axially to the metering roller 3 above the insertion axis 4 into a starting position in which the weft thread 2 is covered by the flyer hook 29. This starting position of the flyer hook 29 is monitored by a sensor 34. As shown in FIG. 8, the flyer hook itself is bent in a z-shape in one plane through the roller axis, the elongated upper leg covering the weft thread 2 that has been shot in. When the flyer hook rotates about the roller axis 5 in the winding direction 41, this upper leg pulls the weft thread in a loop, which shifts with increasing angle of rotation due to an inclination between the leg and roller axis 5 for the first deflection of the leg in the direction of the roller edge and within a full one Rotation on the oblique middle leg and from there to the outer surface of the metering roller 3 changes by the thread drawn from the injection nozzle 11 runs onto the outer surface, while the thread drawn from the catching nozzle 21 is pulled over the end face of the holder 31 and the metering roller 3 until it jumps over the edge 28 of the metering roller 3 onto its outer surface. After a full rotation, the flyer hook 28 is again in the starting position, which is monitored by sensor 34, while the thread in the form of a loop from the shooting nozzle 11 circles the metering roller 3 and the guide pin 30 and runs into the catching nozzle 21. The flyer hook 29 also covers the thread running from the metering roller 3 to the catching nozzle 21, so that the wrapping process can be repeated. After reaching the intended number of wraps, the holder 31 together with the flyer hook 29 is withdrawn axially to the roller axis 5 against the holding forces of the permanent magnets 43 by the previous feed movement 40, so that a safety distance to the metering roller 3 and the thread path is achieved, which will later enable a high-speed metering operation the metering roller 3 enables.

In the non-attached state, the holder 31 is supported on a transfer arm 60, while in the attached state the connection to the transfer arm 60 is interrupted so that the thread can cross the end face of the metering roller 3 when it is wrapped.

A transfer arm is shown in Fig. 8, which is displaceable with its longitudinal axis in the roller axis 5 and is embedded in the radial three cylindrical cams which protrude under pressure from springs 62 and which can also be pressurized via a compressed air connection 63. When the holder 31 is moved into the metering roller, the cylindrical cams 61 are pressurized with compressed air and rest in a holding groove 64. With the fixation of the holder 31 by the magnets 43 the metering roller 3, the compressed air connection 63 is vented. The transfer arm 60 is withdrawn from the holder 31 and during the extraction the cams 61 slide against the spring force out of the holding groove 64 and generate an axial force against the magnetic holding forces. This axial force is somewhat higher than the forces required for entrainment when wrapping. If the sensor 34 continues to signal the presence of the flyer hook 29 while the transfer arm is being pulled out, the magnetic forces checked in this way are considered sufficient for the wrapping.

After wrapping, the transfer arm 60 moves into the holder 31, the cams 61 initially only engaging in the holding groove 64 under pressure from the springs 62. By applying compressed air to the air connection 63, the cams 61 are pressed so firmly in the holding groove that the holder 31 can be pulled out of the metering roller 3 against the magnetic forces, which is confirmed by sensor 34. The cylinder cams 61 are limited by a ring 65 with a bayonet lock and by screws 27 in their radial movement to the outside. According to the extension length of the cylinder cam 61, the receiving bore of the holder 31 is provided with a conical inlet.

The hierarchy of the control 33 of a weaving machine and a possibility of including the previously described measuring devices 1 in it is shown in FIG. 10. A central controller 55 coordinates the operating states and processes of various functional groups 50, 54, 56, 57, the functional group 50 comprising elements, such as sensors and actuators, for the shot preparation, the functional group 54 elements for the operation and automatic threading of the metering device 1 Function group 56 which includes web elements and function group 57 elements for troubleshooting.

Claims (18)

1. A metering device (1) for the weft yarn (2) of a loom, the device having a metering roller (3) which is disposed between a supply unit (10) and a draw-off unit (20) and around which the weft yarn wraps in the metering operation and which determines the weft yarn draw-off speed; a picking nozzle (11) and a catching nozzle (21) on a picking axis (4) which, in a plane substantially perpendicular to the spindle (5) of the metering roller (3), crosses the metering roller (3) parallel to a tangent but at a very reduced distance, characterised in that a catch finger (6) is installed near the generated surface of the metering roller (3) and is rotatable in controlled fashion around the spindle (5) and, by way of a controlled relative movement (40) between a weft yarn (2) on the picking axis (4) and the finger (6), the weft yarn (2) is movable into a catching zone (8) of the finger (6) with the aim of the metering roller (3) having a predetermined number of turns wrapped around it.
2. A device according to claim 1, characterised in that the draw-off unit (20) has a deflecting device (22) and a yarn accumulator (23), which latter receives a newly picked weft yarn by way of the deflecting device (22) and releases such yarn during the wrapping-round of the roller (3) against the picking direction.
3. A device according to claims 1 and 2, characterised in that the draw-off unit (20) has a draw-off element (24) which applies to the weft yarn a tension adjustable in the picking direction.
4. A device according to any of claims 1 to 3, characterised in that the draw-off unit (20) has a severing element (25) which severs a deflected weft yarn (26) on the return of the deflecting device (22).
5. A device according to any of claims 1 to 4, characterised in that the supply unit (10) has a yarn brake (12) which brakes the weft yarn with an adjustable force during the wrapping-round of the metering roller (3).
6. A device according to any of claims 1 to 5, characterised in that the supply unit (10) has a suction nozzle (14) which starts as a slot (13) extending parallel to a presented yarn start (15) and which blows the weft yarn for picking as far as the picking nozzle (11).
7. A device according to any of claims 1 to 6, characterised in that the finger (6) is rigidly connected to an edge (28) of the metering roller (3) and interrupts the same in the wrapping-around direction (41).
8. A device according to claim 7, characterised in that the finger (6) is in the form of a pin (46) in the edge of the metering roller (3), such pin extending outwardly from the roller spindle (5), the pin axis forming an angle of less than 60° with the perpendicular (45) of its base (47) to the spindle (5).
9. A device according to any of claims 1 to 8, characterised in that a deflecting element (9) between the picking nozzle (11) and the catching nozzle (21) deflects the weft yarn (2) transversely to the picking axis (4) into the catching zone (8) of the finger (6).
10. A device according to claim 9, characterised in that the deflecting element (9) is in the form of a guide (36) which is disposed on the picking axis (4) and which guides the picked weft yarn (2) into the catching zone (8) of the finger (6).
11. A device according to claim 9, characterised in that the deflecting element (9) has an edge (7) which extends transversely to the picking axis (4) and which guides the picked weft yarn (2) into the catching zone (8) of the finger (6).
12. A device according to claim 9, characterised in that the deflecting element (9) takes the form of an air stream (39) blowing transversely to the picking axis.
13. A device according to any of claims 1 to 6, characterised in that the metering roller (3) has on the side towards the finger (6) a conically narrowing generated surface (32) with a rounded transition extending towards the projecting edge (28).
14. A device according to any of claims 1 to 6, characterised in that it has a guide pin (30) disposed between the picking axis (4) and the metering roller (3), the guide pin (30) being in the same plane as the spindle (5) and descending in this plane at an adjustable angle < 7° towards the spindle (5) and having at its end an abutment (40) for sliding-off yarns and/or a covering (48) of the roller edge (28).
15. A device according to any of claims 1 to 6 and 13 and 14, characterised in that the finger (6) is in the form of a multicurved open flyer hook (29) which is introducible parallel to the spindle (5) on the other side of the picking axis (4) and around which the spindle (5) is rotatable.
16. A device according to claim 15, characterised in that the flyer hook (29) is retained intermittently by way of a non-positive retainer (31) in an axially retracted position on the metering roller (3).
17. A device according to any of claims 1 to 16, characterised in that a control (33) comprising sensors (34, 35, 18, 51) provides co-ordination and automatic control of the actuating elements for an adjustable number of wraps on the metering roller (3).
18. A transverse shed loom having a rotor, characterised in that it has metering devices (1) according to any of claims 1 to 17 for its picking system and during undisturbed weaving the speed of the roller (3) is associated in an adjustable relationship with the speed of the rotor.

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