EP0943571B1 - Yarn feeder with improved yarn path - Google Patents

Description

The invention relates to a yarn delivery device with the Features of the preamble of claim 1.

For example. in knitting technology, but also on others Fields of textile technology it is often necessary Knitting points or other thread consumption points to supply with defined quantities of textile threads. Therefor so-called positive feeders are in use the required thread consumption point Allocate thread quantity and, regardless of the actual Thread take-off at the thread consumption point, respectively. Such a supplier is, for example, from DE 3601586 C1 and EP 0 234 208 A1, which is considered the closest prior art, known. This supplier is special intended for circular knitting machines, the knitting points with have constant thread consumption. The supplier has a shaft rotatably mounted in a base support on, at one end a thread delivery drum rotatably is held. The other end of the wave is with one Pulley provided which engages with a toothed belt stands. This toothed belt is driven centrally and runs over the pulleys of many such thread delivery devices, which thus drive at the same constant speed are.

The thread delivery drum has an outer circumference, that of a plurality extending axially Rods is set. The rods are in at the end End disks held on their facing the rods Side are essentially conical. The Thread delivery drum is made multiple times by the thread to be delivered wrapped around so that the drum pulled the thread from one Pulls off the bobbin and delivers it to the knitting point. outgoing from the thread drum, the thread is passed through eyelets, which thus define a thread path. The on the thread delivery drum following eyelet is axially against the Thread delivery drum offset so far that the thread is over brushes the edge of the thread delivery drum. This serves the Wiping off the drum Lint and can take up additional thread turns promote when the thread is missing or too low thread take-off at the knitting point and continued constant delivery sags or sags starts. The thread then hangs over the edge and remains lying on the drum.

Thread delivery devices of this type are for applications well suited with essentially constant thread consumption. However, there are also applications for which the thread consumption temporarily very strong fluctuations may be subject to. This is for example with flat knitting machines the case where a thread guide, the individual Feeds the thread one after the other, and moving across the entire width of the web performs. The thread consumption is at the side Arrangement of the thread delivery device, i.e. when feeding the Thread across the web in the outward and return stroke different. In addition, the thread consumption comes in the dead center positions of the thread guide to a complete standstill. In these cases, thread delivery devices cannot be used be used, the thread in time constant Deliver quantity. Rather, it is necessary that the supplied thread an essentially constant tension to maintain a constant mesh size. For this purpose, a thread delivery device is known from DE 19537215 A1, which has a motor-driven thread delivery wheel. This is wrapped around the thread a few times. After that the thread runs to the thread tension sensor Yarn consumption point. The thread tension sensor regulates the speed of the motor of the thread delivery wheel via a Control loop so that the thread tension to the setpoint is settled.

The thread delivery wheel isc by six out of one central hub, wing or wire bracket extending away educated. These each have two parallel spacings mutually arranged, extending in the radial direction Leg on, between which an axially oriented Support section is held. The support section goes with a U-shaped curve, projecting radially outwards Sections in the radial spokes above.

The direction of the thread from the thread delivery wheel is, for example, also at DE 4206607 at right angles to the The axis of rotation of the thread feed wheel is fixed.

In the thread delivery device according to DE 4206607 A1 a thread delivery device with crossing support webs used for the thread. The thread delivery wheel thus points its smallest outside diameter in its central plane on so that a thread fed off-center on this Middle position slips. From this he becomes over a here as a trumpet-shaped coil spring, trained Thread guide means in the middle plane of the thread delivery wheel deducted.

Such yarn delivery devices are more elastic for delivery Threads provided. Such threads are, for example, elastane threads or other plastic fibers. by virtue of Their elasticity is used to monitor thread tension critical. It can also be problematic that the often very thin (hair-fine) threads tend to Lay turns on top of each other or stick together Form turns.

A reproducible and even time uniform separation of those supplied by the thread delivery wheel Thread quantities from the thread delivery wheel Windings is particularly at changing speeds difficult to reach. However, it must be prevented that the thread at high or otherwise critical speeds not released by the thread delivery wheel, but is adherently entrained because this leads to a return and thus would lead to a tearing of the thread.

Proceeding from this, it is an object of the invention Thread delivery device to create the threads with changing Deliver thread travel speeds with good reliability can.

This task is performed with the thread delivery device Features of claim 1 solved.

The thread delivery device according to the invention has a motor-driven one Thread delivery wheel on that around a fixed Axis of rotation is rotatably mounted. The thread path is set so that the thread is not accurate runs tangentially to the thread delivery wheel, but in one acute angle to the tangent. In other words, the thread runs at an acute angle to a plane from, whose normal direction with the axis of rotation of the thread delivery wheel matches. The running thread runs with it of the few turns, on the Thread delivery reel lying away. He is the result of (usually low) tension of the thread on the thread delivery wheel following thread travel path from the thread delivery wheel Cut.

The skew of the thread of the invention Thread delivery wheel thus enables a clean thread run, surprisingly almost completely independent of speed, i.e. both at low speeds and at high speeds as well as abrupt acceleration and / or braking phases. The inclination of the thread delivery wheel causes spacing of the individual turns of the thread winding on the thread delivery wheel from each other. Neither the turns stick to each other, they are still lying one above the other. While at high speeds, the centrifugal forces acting on the thread as well radial air currents releasing the thread from the thread delivery wheel support, so here the separation can be done more easily, the diagonal pull provides support this process even at very low speeds or close to the stop of the thread delivery wheel. On the other hand, the separation of the thread running from the thread delivery wheel takes place very quickly at high speeds, because very little time is available stands. The diagonal draw also favors the thread flow here. The tension of the thread creates an axial force component, which go beyond the expiry point more or penetrates less into the wrap and causes that the thread begins to slide axially in front of the outlet point can. The drain point can be from the adjacent turn be spaced. It can be achieved that independent of speed the angular position of the point at which the running thread separates from the thread delivery wheel, constant remains. Immediately follows the thread delivery wheel a thread tension sensor without thread guide means arranged in between, thread eyelets or the like, this is significant Significance for the constancy of the thread tension. Would the drain point in the circumferential direction of the thread delivery wheel would move forward or backward the angular relationships of the thread tension sensor running thread extremely change what is correct Capturing the thread tension would make it impossible. The constancy of the drain point made possible by the invention however, again enables the correct detection of the thread tension with a thread tension sensor without additional Need to provide thread guide means.

With the invention it is therefore possible in the Thread path following the thread delivery wheel with a Minimum of thread guide means such as eyelets, pins or the like. get along. This is with regard to the thread Friction that would otherwise distort the thread tension would be beneficial.

In an advantageous embodiment is a first Section of the thread path in front of the thread delivery wheel looking radially to the axis of rotation of the thread delivery wheel parallel to the thread path after the thread feed wheel arranged. This is the axis of rotation of the thread delivery wheel diagonally to the otherwise straight thread path. However, the first and second sections are the thread path in the direction of the axis of rotation of the thread delivery wheel offset from each other by an amount that is preferred is greater than the product of the thread thickness and the Number of turns. This will cause the Thread supported on the guide wheel in the axial direction. This is due to the winding on the fader delivery wheel Thread created, the existing coils aside pushes. Due to the inclination, the sliding movement especially improved shortly before the thread runs out so that the last turn of the penultimate Turn separates without sticking to it. In certain circumstances can be achieved that the two turns differ from each other separate shortly before the point at which the The thread lifts off the thread delivery wheel.

Due to the inclination of the thread delivery wheel in relation on the thread path is also enabled that the guide means for the thread that is on the thread delivery wheel follows the thread only in a transverse direction leads, in relation to the thread feed wheel, for example Circumferential direction is. This means that the thread is in a direction parallel to the axis of rotation here still unguided can be. The actual process point arises due to the inclination of the thread delivery wheel against the incoming thread automatically according to the set Slope that is greater than a slope, which defines a winding with adjacent turns. Regarding the axial direction of the thread feed wheel this is a free thread guide, i.e. is no guidance available.

The thread guiding device following the thread delivery wheel can also be designed as a thread tension sensor his. The thread runs at an obtuse angle of preferably more than 130 ° over the sensor (pen). The slight deflection on the pin keeps the friction low. Due to the constancy of the run-off point from the thread delivery wheel this angle can be kept largely constant become what enables reproducible measurement results and ensures.

Thread guide eyes at the entrance and exit of the thread delivery device ultimately make sure that outside influences of the thread delivery device, such as the positioning of thread spools or other thread guide means, no influence on the conditions have the thread delivery wheel.

The thread delivery wheel is preferably lightweight built with few radial arms, making it quick can be accelerated and stopped, which is why regulated or controlled motor is used. The radial arms are formed, for example, by wire brackets attached to a polygonal thread rest on the outer circumference of the thread delivery wheel establish. The corresponding radial arm sections are essentially axial or in a small acute angle to the axis of rotation so that the Edition is somewhat conical.

The individual radial arms can be in on a hub be arranged at equal angular distances. However, can the angular distances also vary slightly to the excitation of natural vibrations of the thread when passing through different ones Avoid speeds.

Fig. 1 ein Fadenliefergerät in einer perspektivischen schematisierten Darstellung, und

Fig. 2 das Fadenliefergerät nach Figur 1, in einer vereinfachten Seitenansicht zur Veranschaulichung der Fadenführung an dem Fadenlieferrad.

Advantageous details of embodiments of the invention are the subject of subclaims and result from the drawing and the associated description. An exemplary embodiment of the invention is illustrated in the drawing. Show it:

Fig. 1 shows a thread delivery device in a perspective schematic representation, and

Fig. 2, the thread delivery device according to Figure 1, in a simplified side view to illustrate the thread guide on the thread delivery wheel.

Description:

A thread delivery device 1 is illustrated in FIG. 1, as it is for example for the supply of elastane threads Flat knitting machines or also for the delivery of other Threads to thread consumption points of other machines Can find application. The thread delivery device 1 is used a thread 2 from a thread source, for example a thread spool, deduct and along a thread path 3 to the thread consumption point not further illustrated promote. This should be as appropriate as possible Quantity or with constant thread tension.

The thread delivery device 1 has a housing 4 whose essentially flat front side 5 is a thread delivery wheel 6 is arranged, which serves the thread 2nd to promote needs. The yarn feed wheel 6 is like Figure 2 illustrates rotatably mounted about an axis of rotation 7. For this purpose, it is preferably one on an output shaft 8 designed as a disc rotor motor 9 attached in the interior of the housing 4th is stationary. The thread feed wheel 6 is in Lightweight construction. Starting from its hub 9 wings or arms 11 extend radially outwards, which are formed by wire brackets. These are among themselves equally trained. Each arm 11 is two apart parallel to each other radially away from the hub 9 extending radial spoke sections 13, 14 on the outer periphery of the yarn feed wheel 6 by a Support web 15 are interconnected. As from a figure 2 shows, the support webs 15 are essentially just formed wire sections that point in one Angles to the axis of rotation 7 are aligned. You go on both ends with a radial projection 16, 17 in the radial spoke sections 13, 14 over.

In the present embodiment there are six arms 11 provided at equal angular intervals of 60 ° are arranged. However, there can be different angles can be chosen to excite vibrations on the thread 2 to avoid.

The disc motor 9 and the thread delivery wheel 6 belong to a control loop for regulating the thread conveyance depending on the tension of the thread 2. This is detected by a sensor 21, which is on the thread delivery wheel 6 following on the front 5 of the housing 4 of the thread delivery device 1 is arranged. The thread tension sensor 21 has a support pin 22 which with a force sensor is connected. This detects thread tension dependent slightest movements of the pen 22 in the transverse direction. This is shown in Figure 1 by a Arrow 23 indicated. Between the thread feed wheel 6 and the support pin 22 of the thread tension sensor 21 preferably no further thread guiding or guiding means intended.

To define the thread path 3 also serve Thread delivery wheel 6 and the support pin 22 of the thread tension sensor 21 one arranged in front of the yarn feed wheel 6 Thread inlet eyelet 25 and one on the thread tension sensor 21 following thread outlet eyelet 26. These are arranged so that they have a first section 31 of the thread path 3 in front of the thread delivery wheel and a second section 32 of the Thread path 3 offset parallel to the thread feed wheel 6 to each other, as shown in Figure 2. This spatial position of the first and the second section 31, 32 of the thread path 3 results as a result the position of the thread inlet eyelet 25 and the thread outlet eyelet 26 in connection with an inclined position of the thread feed wheel 6 and, if necessary, a corresponding orientation of the support pin or its longitudinal central axis 33. The Thread 2 touches after the thread inlet eyelet 25 and has passed through the first thread path section 31 which Thread delivery wheel 6 for the first time at a contact point 35. Von from here it turns in at least one turn around the thread delivery wheel led around to a drain point 36, that related to the axis of rotation 7 of the yarn feed wheel 6 is axially offset against the contact point 35.

The positioning of the thread inlet eyelet 25 and the thread outlet eyelet 26 with respect to the thread delivery wheel 6 generated axial offset between these two points 35, 36 is larger than that due to the thickness of the thread 2 predefined pitch of the turns on the thread delivery wheel 6, so that the running thread 2 on the thread delivery wheel 6 lying turns are not touched. Regarding a center plane indicated by dash-dotted lines in FIG 41 of the yarn feed wheel 6, on which the axis of rotation 7 is perpendicular stands, this is done by arranging the thread inlet eyelet 25 below and arrangement of the thread outlet eyelet 26 reached above this median plane 41. On the thread 2 this means that the first path section 31 is off Side view (Figure 2) parallel to the leaking Section 32 is offset, the parallel offset larger is than the number of 6 available on the yarn feed wheel Turns multiplied by the thread thickness. This results in an acute angle between the thread travel 3 and the middle plane 41, preferably some is a few degrees.

Relative to the longitudinal direction 33 of the support pin 22, however, are the inlet eyelet 25 and the outlet eyelet 26 at almost the same height. This results in a parallel offset between the accumulating and the expiring Thread. This is ultimately due to the inclination the axis of rotation 7 reached. This is with regard to one Pitch angle of an imaginary on the yarn feed wheel 6 Thread angle, the turns of which lie against each other, larger than the resulting slope angle. This means that the angle α between the median longitudinal plane 41 and an imaginary connecting line between the inlet eyelet 25 and the outlet eyelet 26 larger than that Pitch angle of a wrap with one another Pitch angle of a wrap with one another Turns is. The angle α is preferably greater than twice the pitch angle. This results in gaps between the turns of the winding that are draining ensure the thread under all conditions.

The thread delivery device 1 also has a calibration device 45 for the thread tension sensor 21. The calibration device 45 contains two thread support pins 46, 47, the normal operation of the thread delivery device 1 are lifted from the thread 2, i.e. with this are not engaged. At certain intervals you can the thread support pins 46, 47 by actuating one Traction magnet 48 adjusted in the direction of arrow 23 be that the thread 2 from the pin 22 of the thread tension sensor 21 take off. This serves to find the zero point. If required and / or as an alternative, the thread tension sensor can also be used 21 can be moved for calibration.

The thread delivery device described so far works as follows:

In operation, the thread tension sensor 21 detects the existing tension of the thread 2 corresponding to the lateral Deflection of the pin 22, which is, however, slight and is in the range of one millimeter. The thread consumption on a downstream of the thread delivery device 1 Thread consumption point, for example the knitting point of one knitting machine is reflected in the thread tension, which is constantly corrected by a control loop. For this purpose, the motor 9 is controlled so that the thread delivery wheel 6 provides the amount of thread required to to keep the thread tension constant. The increases Voltage, the motor 9 is accelerated until the Thread tension has returned to its setpoint. If the thread tension drops, the thread feed wheel is slowed down (if necessary to a standstill) until the desired Thread tension is set again.

Regardless of the speed of the thread feed wheel 6 the incoming thread 2 runs in the vicinity of its radial projections 17 on the outer circumference of the thread delivery wheel 6 on an inclined section of the respective radial projection 17, wherein all inclined sections define a conical surface. The thread 2 wraps around the thread delivery wheel or a few times (three to five times) with an incline, which roughly corresponds to its thickness. Thread 2 runs then near or above the middle plane 41 without touching the radial projections 16. So be the edges defined by the radial projections 16, 17 of the thread delivery wheel, although the thread 2 is in relation to the thread delivery wheel 6 slants in and out does not touch. Due to the inclination of the axis of the thread delivery wheel through an angle that is greater than the pitch angle of the winding results at the run-off point an axial force component as a result of the thread tension the thread running against the middle plane 3. The running thread 2 is therefore not liable due to mechanical more electrostatic or any other effects on the thread delivery wheel or on adjacent turns. It this results in a quiet and even process of thread 2. Ideally, several or all of them Windings be spaced apart.

In a thread delivery device 1, the needs-based Positive delivery of a thread 2 with an electric motor 9 connected thread delivery wheel 6 has a thread path 3, which is guided by thread guide means 25, 26 at an angle to the axis of rotation 7 of the yarn feed wheel 6 is set, which is greater than the sum of 90 ° and an additional acute angle. This additional acute angle α is greater than the pitch angle a thread winder on the thread delivery wheel 6, in the adjacent Windings lie against each other. This gives there is a smooth flow of the lying on the thread delivery wheel 6 Thread 2.

Claims (17)

1. A thread feeding apparatus (1) for the feeding of threads to thread consuming locations with thread consumption fluctuating with time,
      having a thread feeding wheel (6) which is rotatably mounted about an axis of rotation (7) and is arranged in a thread path (3) and has substantially straight axial support sections (15) so that a thread (2) can be wrapped around it,
      having a motor (9) which is connected to the thread feeding wheel (6) in a manner precluding relative rotation so as to drive the latter and deliver the thread (2),
      having an inlet thread-guiding device (25) which is arranged upstream of the thread feeding wheel (6) so as to define the thread path (3),
      having a thread tension sensor (21) which has a support pin (22) which is disposed in the thread path (3) immediately downstream of the thread feeding wheel (6), the thread being applied against the support pin (22) at an obtuse angle which is greater than 130°, wherein the support pin (22) is connected to a sensor device (21) to detect the thread tension,
      having an outlet thread-guiding device (26) which is arranged in the thread path (3) downstream of the thread tension sensor (21) so as to define the thread path (3),
      wherein following the thread feeding wheel (6) the thread path (3) is defined at an acute angle α differing from zero, to which the axis of rotation (7) is perpendicular.
2. A thread feeding apparatus according to Claim 1, characterised in that the thread (2) is guided through the thread-guiding devices (25,26) and by the thread-directing device (22) unwinding from the thread feeding wheel (6) without peripheral contact.
3. A thread feeding apparatus device according to Claim 1, characterised in that the thread path (3) defined by the thread-guiding devices (25,26), the thread-directing device (22) and the thread feeding wheel (6) has a first section (31) leading to the thread feeding wheel (6) and a second section (32) leading away from the thread feeding wheel (6), and in that the first section (31) is disposed in a plane which is parallel to a plane including the second section (32).
4. A thread feeding apparatus according to Claim 3, characterised in that the distance between the planes is greater than the product of the maximum thread thickness and the maximum number of turns with which the thread (2) is wrapped around the thread feeding wheel (6).
5. A thread feeding apparatus according to Claim 1, characterised in that the directing device (22) guides the thread (2) exclusively in a first transverse direction (23), wherein the thread-directing device (22) is preferably in the form of a pin (22) by way of which the thread (2) runs freely movably in the pin longitudinal direction (23).
6. A thread feeding apparatus according to Claim 1, characterised in that the directing device (22) is mounted substantially immovably.
7. A thread feeding apparatus according to Claim 5, characterised in that the pin (22) has a longitudinal axis (33) which forms with the axis of rotation (7) an acute angle which is preferably smaller than 10°.
8. A thread feeding apparatus according to Claim 1, characterised in that the outlet thread-guiding device (26) guides the thread (2) at least in a second transverse direction and is in the form of an eyelet.
9. A thread feeding apparatus according to Claim 1, characterised in that the guiding device (26) and the section (32) of the thread path arising between the thread feeding wheel (6) and the guiding device are disposed in a plane which intersects the thread feeding wheel (6) at its entire periphery.
10. A thread feeding apparatus according to Claim 1, characterised in that the angle (α) is greater, preferably greater than twice as great, as a gradient angle which is present in a thread reel with turns arranged without spacing on the thread feeding wheel (6).
11. A thread feeding apparatus according to Claim 1, characterised in that the motor is controlled by an actuating device which controls it on the basis of the thread tension.
12. A thread feeding apparatus according to Claim 1, characterised in that the motor (9) is a low-inertia motor, preferably disc armature motor.
13. A thread feeding apparatus according to Claim 1, characterised in that the thread feeding wheel (6) has a plurality of radial arms (11) of substantially like design, which are arranged relative to one another at preferably equal angular distances apart.
14. A thread feeding apparatus according to Claim 13, characterised in that the radial arms (11) are arranged at alternating angular distances apart.
15. A thread feeding apparatus according to Claim 13, characterised in that the radial arms (11) are formed by wire stirrups which each have two radial spoke portions (13,14) which are joined together by a substantially axial support section (15).
16. A thread feeding apparatus according to Claim 15, characterised in that a radial projection (16,17) is formed at the transition between the axial portion (15) and the radial spoke portion (13,14).
17. A thread feeding apparatus according to Claim 1, characterised in that the guiding device (25) is disposed with the section (31) of the thread path (3) arising between the thread feeding wheel (6) and the guiding device (25) in a plane which intersects the thread feeding wheel (6) at its entire periphery.

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