EP1786715B1 - Thread tensioner - Google Patents

Abstract

The invention relates to a thread tensioner (B) comprising tensioning elements (E1, E2) that define a thread tensioning zone. In said tensioner, the first tensioning element (E1) rests on a stop (1) and the second tensioning element (E2) can be pressed against the first tensioning element (E1) by means of an adjustable magnetic contact force (Fm) produced by a magnetic armature (A) and a repelling magnetic actuator (M). The stop (1) is located on the opposite side of the thread tensioning zone from the first tensioning element (E1). The first tensioning element (E1) is stressed by a spring force (f2) in the direction of the second tensioning element (E2) against the stop (1). Said spring force (f2) is greater in the thread tensioning zone than the respectively adjusted maximum magnetic contact force (fm). The mass of (mE1) of the first tensioning element (E1) is smaller than the mass (mA) of the magnetic armature (A).

Description

The invention relates to a yarn braking device specified in the preamble of claim 1 and claim 2.

At the EP-A-1 072 707 known yarn braking device which can be pressed by the adjustable Magnetanpresskraft against the first stationary brake element second brake element arcuately and flexibly and with both ends of the arc in a rigid rod, which is connected without play with the magnetic armature. The flexible second brake element defines a spring arrangement whose spring force, which generates the contact pressure of the second brake element against the first brake element, is controlled by a linear electric motor. In order for the linear motor to be able to carry out the intended working stroke of its rotor, the spring force must not be greater than the respectively set maximum magnetic contact force, otherwise the linear motor could not overcome the spring force and could not execute a stroke. How the yarn braking device behaves when passing a node in the thread through the yarn braking zone between the first and second brake elements is not disclosed.

At the EP-A-0 961 393 . Fig. 3 , Known yarn braking device is provided for adjusting an initial position of the second brake element connected to the magnetic element, a return spring which acts on the magnetic armature in the direction of a stopper damping elastic part. How the yarn braking device behaves when passing a node in the thread is not disclosed.

At the DE-U-87 13 749 known yarn braking device, the magnetic armature is a coil which is adjustable relative to rod-shaped permanent magnet and is connected to the second brake element. Between the coil and a brake shoe of the second brake element, a rubber buffer is attached. How the yarn braking device behaves when passing a node in the thread is not disclosed.

From US 5,979,810 ( DE 195 31 579 B1 ) known yarn braking device has plate-shaped brake elements. The first brake element is pressed by the second brake element with the adjustable Magnetanpresskraft against the stationary stop. The repulsive magnet is arranged on the rear side of the second brake element facing away from the first brake element and acts on the magnetic armature arranged in the second brake element. The Magnetanpresskraft can be changed while the thread is running and continuously. In the case of a thickening or a knot in the thread, the mass of the second brake element together with the mass of the magnetic armature and against the repulsive magnetic force of the magnet must be pushed away from the first braking element supported on the stationary stop. Due to the inertia of the large mass, especially the magnetic armature creates a momentary increase in thread tension, which can lead to tearing of the thread.

At the US 6 161 595 A known yarn braking device, the first brake element is provided on a stationary magnetic body. The second brake element is movable relative to the first brake element and is urged by the first brake element through a magnet with pulling magnetic force. When passing a node in the thread, the second brake element is moved against the magnetic force from the first brake element away, with the decisive for the strength of the magnetic force gap width changes, even if the second brake element only tilts laterally. This instantaneous enlargement of the gap width significantly reduces the magnetic force, so that the braking effect is reduced and the second braking element returns to the starting position relatively delayed after the node has passed through with a critical transient. With thick thread material, the recovery takes place very slowly and with a significant settling.

At the WO03 / 033385 A1 known yarn braking device, the first brake element is provided on a stationary magnetic body. The second brake element is held in a self-movable manner in a hinged lid which engages over the magnetic body and is acted upon by the first brake element with pulling magnetic force and pressed against the first brake element. Upon passage of a thickening or a knot in the thread, the second brake element is lifted against the pulling magnetic force, whereby the strength of the magnetic force is reduced and changes the braking effect. Especially with thick thread material, the provision of the second Decelerate brake element after passage of a knot or thickening or run with a transient, during which the braking effect varies.

The invention has for its object to provide a yarn braking device of the type mentioned above, which allows thickening and knots in the thread pass without risk to the thread, the braking effect is not noticeably changed, and adjusts the passage of the node or thickening directly back to the original braking effect , The yarn braking device should be particularly suitable for thick yarn qualities.

The stated object is achieved according to the invention either with the features of claim 1 or with the features of the independent claim 2.

The function of the yarn braking device according to the invention takes into account the phenomenon that a node passing through the yarn braking zone (or a thickening) when the yarn is running at relatively high speed generates a relatively high-frequency momentary energy impact transversely to the yarn running direction. On the occurrence of the energy pulse either speaks according to claim 1, the first brake element under withdrawal from the stationary stop against the spring force to yield, while the second brake element and the mass of the solenoid valve inertially not react appreciably, or are according to claim 2, the second brake element against the spring force while the solenoid valve does not react appreciably thanks to its large mass. In any case, it is ensured that the braking effect during passage of the node is not noticeably reduced, because the set Magnetanpresskraft or the spring force remains substantially unchanged. Furthermore, the deflected braking element, since it is still under undiminished force of the spring force, returns immediately after passage of the node and without swinging back to the starting position. The yarn braking device is equally suitable for practically all thread qualities with this design, but especially for thick thread material, which generates a considerable release movement when a knot or a thickening passes. The mass of the respective brake element is designed so small that it can be displaced by the energy impact of the node, while the much larger mass of the solenoid valve does not shift under the influence of this energy impact.

According to claim 1, the mass of the first spring element is displaced against the spring force at a node, while the magnetic armature with the second brake element remains at least substantially motionless. During normal braking of the thread without a knot or thickening, the first spring element remains under spring force on the stationary stop so that it acts as a stationary braking surface for the second brake element.

According to claim 2, the spring arrangement provided between the second brake element and the magnetic armature forms a mass decoupling upon passage of a node, so that the second brake element is displaced from the node against the spring force and relative to the magnetic armature with substantially immobile magnetic armature.

In both cases, when a node passes, the previously set braking effect does not change. In addition, the displaced brake element returns immediately after passage of a node in the starting position, since it remains burdened by the possibly even increased spring force or the spring force and the set Magnetanpresskraft.

Suitably, the yarn brake is a controlled leaf spring brake, in which the first brake element is a leaf spring, and the second brake element is a brake surface forming body.

It could also be a different type of controlled thread brake, the first and / or second brake element is not based on a leaf spring, but for example, is rigid.

The leaf spring is expediently J-shaped with a cantilevered end, and is anchored to the J-hook on a, preferably drehverstellbaren, abutment. From the abutment, the spring force is generated, with which the leaf spring is pressed against the stationary stop, so that the leaf spring behaves like a stationary braking surface during normal braking operation or does not leave the stationary stop, even at maximum set Magnetanpresskraft appreciably. By means of a rotationally adjustable abutment can be, for. adjust the effective spring force as needed.

The second brake element is suitably a U-shaped body, which may be rigid or resilient, e.g. a leaf spring body which is movably supported in a guide approximately in the direction of the adjustable Magnetanpresskraft. The guide positions the body relative to the leaf spring and so that the set Magnetanpresskraft in the braking zone comes to effect as desired. In addition, the guide can allow easy replacement of the second brake element.

In an expedient embodiment, the leaf spring (first brake element) is wider at least in the area of the stationary stop than the body forming the braking surface (second brake element). The leaf spring is supported with the over the body laterally projecting edge portions of the stationary stop.

The repelling Magnetaktuator expediently has a proportional solenoid coil which is connected to a current control. In this way, it is possible to adjust the braking force of the magnetic armature, such as a permanent magnet, extremely quickly and sensitively, for example when using the yarn braking device between a yarn feeding device and a protect looser loom, occur in the relatively high yarn speeds and the most uniform possible yarn tension is desired , which may need to be changed several times within one entry procedure. The magnetic pressing force depends directly on the magnitude of the energizing current of the coil.

In one embodiment, a stable support of the leaf spring is achieved in that ribs are provided on both sides of the body for both edge regions of the leaf spring.

In a particularly advantageous embodiment, two yarn braking devices are arranged on a common carrier substantially mirror images of each other, preferably with an offset in the yarn running direction. This yarn braking device is compact and can be used for processing two threads running close to each other. Nevertheless, each yarn braking device is individually controllable.

In a structurally simple, functionally reliable and compact embodiment of the braking surface forming body is arranged on a plate, preferably with interposition of a resilient member, and the plate via a connection to the magnetic armature, preferably a permanent magnet coupled. The magnetic armature is guided together with the plate in an axial guidance, so that the magnetic armature smoothly transmits the Magnetanpresskraft and the plate acts on the second brake element centered.

The axial guide is supported in a preferred embodiment in a housing of the Magnetaktuators.

The ribs defining the stationary stop for the first brake element can also be expediently arranged on the housing, preferably even in one piece.

The compound, which takes over the leadership task and the power transmission, has a guide body on which the plate is held by a clamping element and an axially and radially compressed O-ring. The guide body can provide a long guide surface for axial guidance. The compressed O-ring centers and provides a desirable elasticity in the connection.

Since such a braking device expediently works with a low base braking effect when the coil is not energized, it is expedient to place in alignment and at an axial distance from the magnetic armature a stationary auxiliary permanent magnet having an opposite polarity of the magnetic armature polarity, and the magnetic armature permanently impinged. Instead of such a permanent magnet, alternatively, a light spring, which can be adjustable, could be provided.

Fig. 1

schematisch eine erste Ausführungsform einer Fadenbremsvorrichtung, bei normalem Fadenlauf,

Fig. 2

die Bremsvorrichtung von Fig. 1 bei Durchgang eines Knotens im Faden,

Fig. 3

schematisch eine andere Ausführungsform einer Fadenbremsvorrichtung, bei normalem Fadenlauf,

Fig. 4

die Fadenbremsvorrichtung von Fig. 3 bei Durchgang eines Knotens im Faden,

Fig. 5

eine Perspektivdraufsicht auf eine weitere Ausführungsform einer Faden- bremsvorrichtung,

Fig. 6

einen Axialschnitt durch einen Hauptteil der Fadenbremsvorrichtung bei- spielsweise der Fig. 1, 2 und 5, und

Fig. 7

eine Explosionsdarstellung zu Fig. 6.

With reference to the drawings, embodiments of the subject invention will be explained. Show it:

Fig. 1

schematically a first embodiment of a yarn braking device, with normal yarn path,

Fig. 2

the braking device of Fig. 1 upon passage of a knot in the thread,

Fig. 3

schematically another embodiment of a yarn braking device, in normal yarn path,

Fig. 4

the yarn braking device of Fig. 3 upon passage of a knot in the thread,

Fig. 5

3 is a perspective top view of a further embodiment of a thread brake device,

Fig. 6

an axial section through a main part of the yarn braking device, for example, the Fig. 1, 2 and 5 , and

Fig. 7

an exploded view too Fig. 6 ,

In the Fig. 1 and 2 a yarn braking device B is shown schematically in a position during normal yarn travel and in a position when passing a node in the thread.

The yarn braking device B has a first brake element E1, for example a leaf spring L, which is pressed by a spring 2 or by a corresponding bias with a spring force f2 against a stationary stop 1. The spring 2 is supported e.g. on a stationary abutment 3 from. The spring force f2 is optionally adjustable. The first brake element E1 has a mass mE1.

Further, the yarn braking device B, a second brake element E2, which is also a braking surface forming body F, for example, a leaf spring body F, wherein the first and second brake elements E1, E2 are arranged relative to each other so that in a thread running direction of a dot-dash line indicated thread Y tapered inlet gap 4 leads to a braking zone between the brake elements E1, E2. The second brake element E2 is located on the side of the stopper 1, but is freely movable relative to the stationary stop 1. With the second brake element E2, a magnetic fitting A is connected, which has a mass mA. The magnetic armature A is acted upon by an adjustable Magnetanpresskraft fm of a repulsive Magnetaktuators M and pressed against the first brake element E1. The magnetic actuator M suitably contains a proportional electromagnetic coil which is connected to a current control CU and generates the magnetic contact force fm in accordance with the application of current. The magnetic armature A is e.g. a permanent magnet, so that a repulsive linear magnetic actuator M is formed.

The spring force f2 for the first brake element E1 is greater, at least in the braking zone, than the respectively set maximum magnet contact force fm. The mass mE1 of the first brake element E1 is, at least in the braking zone, smaller than the mass mA of the magnetic armature A.

With normal thread pass ( Fig. 1 ), the yarn Y in the braking zone is braked in accordance with the magnitude of the set magnetic contact force fm, with the first braking element E1 at least substantially being held on the stationary stop 1.

Occurs in the yarn Y a thickening or a knot K ( Fig. 2 ), then the node K passes through the yarn brake device B with the possibly relatively high running speed of the yarn Y. The node K generates an energy impact, which tries to move the two brake elements E1, E2 away from each other. Since the mass mA of the magnetic armature A, which acts with the set Magnetanpresskraft fm via the second brake element E2 in the yarn braking zone on the first brake element E1 and has a certain inertia, because of the mass mA by the Energieimpakt not appreciable in Fig. 2 can be displaced to the left, gives the first brake element E1 with its relation to the mass mA possibly much smaller mass mE1 under the energy impact and against the spring force f2, because the energy impact a in Fig. 2 generated rightward force fK. However, during the passage of the knot K, the set magnetic pressing force fm and also the spring force f2 continue to act, so that the braking effect does not noticeably change. As soon as the node K has passed, the low mass mE1 of the first brake element E1 returns immediately under the spring force F2 to the position of FIG Fig. 1 back.

The in the 3 and 4 embodiment of the yarn braking device B shown differs from that of Fig. 1 and 2 in that the spring force f2 is generated for example by a spring arrangement 2 'between the magnetic armature A and the second brake element E2, which has a mass mE2, which is significantly lower than the mass mA of the magnetic armature A. The spring force f2 is greater than the respective set maximum magnetic contact force fm. The second brake element E2 is either formed on the stationary stop 1 or arranged there as a body F, which is located on the side facing away from the second brake element E2 side of the braking zone. Normal threadline (no knots or thickening, Fig. 3 ), the second brake element E2 is pressed against the first brake element E1 with the set Magnetanpresskraft fm. The spring assembly 2 'is not noticeably compressed, since the spring force f2 is greater than the respective set maximum Magnetanpresskraft fm. There is a dependent on the energization of the magnetic coil braking effect.

As soon as a node K occurs in thread Y ( Fig. 4 ), the mass mE2 of the second brake element E2 becomes substantially motionless relative to that due to inertia persisting mass mA of the magnetic armature and against the spring force f2 by the energy impulse resulting force fK shifted to the left to pass through the node K. In this case, the Magnetanpresskraft fm acts unchanged, and also thanks to the compression of the spring assembly 2 'an even slightly higher spring force f2, so that the set braking effect despite the node K does not change significantly. As soon as the node K has passed, the second brake element E2 immediately returns to the position according to FIG Fig. 3 back, under the forces fm and f2. In this case, no transient occurs since the lower end of the leaf spring body F (second brake element E2) is already reset, while the node is on its way out of the yarn braking device.

Fig. 5 shows a concrete embodiment of a yarn braking device B, in which two yarn braking devices approximately in the Fig. 1 and 2 shown type are arranged together on a support 5. On the carrier 5 yarn loops 6 are provided, which basically set the yarn paths through the two yarn braking devices. Each yarn braking device could also be arranged in a single arrangement on a carrier 5.

Each first brake element E1 is a leaf spring L in the form of a J, wherein the free end 10 of the J cantilevered, and the J-hook is anchored to an abutment 8 arranged on the support 5 so that in the respective braking zone, the first brake element E1 is pressed against the stationary stop 1 with the spring force f2. The spring force f2 can be adjusted for example by turning the abutment 8.

Each magnetic actuator M is contained in a housing 7, on which the stationary stop 1 in the form of two ribs R is formed. The second brake element E2 here is a U-shaped body F, e.g. from a leaf spring or optionally of a rigid material, which is narrower than the leaf spring L, so that the leaf spring L rests with its lateral edge regions on the ribs R.

For the second brake element E2, a movement guide 11, 12 is provided on the magnet housing 7, for example in the form of longitudinal slots 12 in the legs of the U, in which pins 11 engage. This longitudinal guide allows mobility of the second brake element in variations of the Magnetanpresskraft and / or in the braking operation.

Fig. 6 is an axial section through main components of the yarn braking device B about the Fig. 5 and the Fig. 1 and 2 , while Fig. 7 an associated exploded view is. The magnetic actuator M is housed with the coil in the housing 7 and defines an inner channel in which the magnetic armature A (a permanent magnet) linearly movable and by the repulsive magnetic force fm in Fig. 6 can be acted upon to the right. Optionally, a stationary auxiliary permanent magnet PM may be placed in the housing 7, which is axially aligned with and axially spaced from the magnet armature A. The auxiliary permanent magnet PM generates a weak magnetic urging force for the second brake element E2 to generate a base braking effect even when the coil is not energized.

The stationary stopper 1 is defined by the ribs R integrally formed on the magnet housing 7, which constitute the second braking element E2, i. the leaf spring body F, record without contact between them.

The braking surface forming the body F, here bent for example from a spring plate, rests on a plate 13, wherein optionally a resilient member 14 is interposed, which is positioned in a recess of the plate 13, such that the rear side of the body F the plate 13 may not be contacted. The plate 13 is coupled to the magnetic armature A via a connection 15, the clamping elements 17, 17 a and a guide body 16 has. Between the guide body 16 and the plate 13 a under the action of the clamping element 17a axially and radially compressed O-ring 18 is provided to integrate a certain elasticity in the connection 15 and to center the plate 13 clean and somewhat yielding. The guide body 16 is axially guided in an axial guide 19, such that the guide body 16 guides both the magnetic armature A and the plate 13 in the axial direction. The axial guide 19 could be a plastic sleeve which is fixed in the housing 7. The body F is formed, for example, of a thin spring steel strip quadrangular shape by bending U-shaped, wherein it on its braking side a square flat braking area, then slightly receding Areas, and round end portions to the U-legs containing the slots 12 ( Fig. 7 ).

The plate 13 (and / or the guide body 16) deforms the O-ring 18 with a conical or rounded chamfer 13a and the guide body 16 with an axial distance, so that here a clean centering of the plate 13 is formed, and yet a certain Mobility of the plate 13 relative to the guide body 16 is possible.

Instead of the auxiliary permanent magnet PM and a weak, the basic braking effect adjusting spring could be arranged in the housing 7.

Claims (15)

1. Thread tensioner (B), comprising first and second tensioning elements (E1, E2) defining a thread tensioning zone, of which tensioning elements the first tensioning element (E1) is co-acting with a stationary stop (1), and the second tensioning element (E2) is pressed against the first tensioning element (E1) with an adjustable magnet pressing force (fm) by a magnet armature (A) connected to the second tensioning element (E2) and by a repelling magnet actuator (M), characterised in that the stationary stop (1) is provided at the side of the thread tensioning zone remote from the first tensioning element (E1), that the first tensioning element (E1) is loaded by a spring force (f2) in the direction towards the second tension element (E2) and against the stationary stop (1), that the spring force (f2) is larger in the tensioning zone than the respective adjusted maximum magnet pressing force (fm), and that the mass (mE1) of the first tensioning element (E1) is smaller than the mass (mA) of the magnet armature (A).
2. Thread tensioner (B), comprising first and second tensioning elements (E1, E2) defining a thread tensioning zone, of which tensioning elements the first tensioning element (E1) is co-acting with a stationary stop (1) and the second tensioning element (E2) is pressed with adjustable magnet pressing force (fm) against the first tensioning element (E1) by a magnet armature (A) connected to the second tensioning element (E2) and by a repelling magnet actuator (M), the stationary stop(1) being provided at the side of the thread tensioning zone remote from the second tensioning element (E2) and comprising the first tensioning element (E1), and a spring assembly (2') being provided between the magnet armature (A) and the second tensioning element (DE2) which is movable relative to the magnet armature (A) counter to a spring force (f2) of the spring assembly (2'), characterised in that the mass (mE2) of the second tensioning element (E2) is smaller than the mass (mA) of the magnet armature (A), that in the thread tensioning zone the spring force (f2) is larger than the respective adjusted maximum magnet pressing force (fm), and that in case of a passage of a knot (K) in the thread (Y) through the thread tensioning zone the mass (mE2) of the second tensioning element (E2) is dislocated in a direction away from the first tensioning element (E1) counter to the spring force (f2) and relative to the mass (mA) of the magnet armature (A) which remains substantially motionless contingent by inertia.
3. Thread tensioner according to claim 1, characterised in that the first tensioning element (E1) is a leaf spring (L).
4. Thread tensioner according to claim 3, characterised in that the leaf spring (L) has the shape of a J with a freely cantilevering end (10) and a J-hook (9) which is anchored to a, preferably rotatably adjustable, support.
5. Thread tensioner according to claim 1 or claim 2, characterised in that the second tensioning element (E2) is a, preferably substantially U-shaped, body (F) forming a tensioning surface, preferably a U-shaped bent spring strip, and that the body (F) is movably held in a guidance (11, 12) such that it is movable at least substantially in the direction of the adjustable magnet pressing force (fm).
6. Thread tensioner according to claim 3 or claim 4, characterised in that the leaf spring (L) at least in the region of the stationary stop (1) is broader than the body (F).
7. Thread tensioner according to claim 1 or claim 2, characterised in that the repelling magnet actuator (M) comprises a proportional electromagnet coil connected to a current control (CU).
8. Thread tensioner according to claim 3 and claim 4, characterised in that the stationary stop comprises ribs (R) for both edge regions of the leaf spring (L), the ribs (R) being provided at both sides of the body (F).
9. Thread tensioner according to claim 1 or claim 2, characterised in that two thread tensioners (B) are provided substantially mirror reversed fashion at a common carrier (5), preferably with an offset in thread running direction between the two thread tensions (B).
10. Thread tensioner according to claim 3 or claim 4, characterised in that the body (F) is resting on a disc (13), preferably with a spring elastic member (14) between the body (F) and the disc (13), that the disc (13) is coupled via a connection (15) with the magnet armature (A), which, preferably, is a permanent magnet, and that the magnet armature (A) and the disc (13) are guided in an axial guidance (19).
11. Thread tensioner according to claim 10, characterised in that the axial guidance (19) is secured in a housing (7) of the magnet actuator (M).
12. Thread tensioner according to claim 8, characterised in that the ribs (R) are, preferably unitarily, provided at the housing (7).
13. Thread tensioner according to claim 10, characterised in that the connection (15) comprises a guiding body (16), and that the disc (13) is supported, and centred, preferably yieldably, at the guiding body (16) via a fastening element (17a) and an axially and radially compressed O-ring (18).
14. Thread tensioner according to claim 13, characterised in that an axial clearance is formed between the disc (13) and the guiding body (16), and that the disc (13) and/or the guiding body (16) is provided with a conical or rounded chamfer (13a) compressing the O-ring (18) positioned in-between via the fastening element (17a).
15. Thread tensioner according to claim 11,characterised in that an auxiliary permanent magnet (PM) is arranged in the housing (7) in alignment with and in axial distance from the magnet armature (A), and that the auxiliary permanent magnet (M) has a polarisation which is opposite to the polarisation of the permanent magnet armature (A).

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