EP1121318B1 - Yarn tension device and yarn feeding apparatus with a yarn tension device - Google Patents

Abstract

A ring-shaped, thin walled braking body with a circumferentially continuous and conical braking surface in a yarn brake for a yarn feeding device. The braking body is held by a first spring assembly in its outer region in a ring-shaped carrying structure. The braking body is formed as a closed circular ring with the conical braking surface positioned adjacent to the inner diameter. The braking surface is continued by a plurality of outwardly extending lamellas having an arc curvature. The lamellas define the first spring assembly. The outer ends of the spring lamellas are interconnected by a ring element which can be mounted to the carrying structure. In a yarn feeding device equipped with the yarn brake, the carrying structure is supported in an universal joint such that it can tilt relative to the support to all sides.

Description

The invention relates to a thread brake according to the preamble of claim 1 and a yarn delivery device according to the preamble of claim 17.

In a known from DE-U-94 06 102 to be mounted on a thread delivery device Thread brake is the brake body using a thin-walled metallic ring band the shape of a truncated cone, the inside of which is the one with the trigger edge of the Storage drum forms cooperating braking surface. The brake body is by means of a in cross section rectangular, overall frustoconical foam ring in Supported outer edge area of the support structure, with the foam on the back of the brake body and in the annular support structure is glued. The Support structure is via a group concentric to the central axis of the thread brake axial coil spring supported in the stationary support of the thread delivery device. The foam forms a first spring device, which it the braking surface allows you to give in locally in the passage area of the thread, but also the axial preload exerted by the axial coil springs on the braking surface has to be transferred. The supporting structure is rigid. The first spring device acts in essentially on the diameter of the braking surface. The necessary guarantees or adhesives are technically complex and solve in the operation of Thread brake light. Furthermore, the gluing points cause inhomogeneities, which in the Orbital movement of the withdrawn thread between the braking surface and the trigger edge Cause fluctuations in thread tension and also decompose can. Correct centering of the brake body on the trigger edge can cannot be ensured under all operating conditions.

The invention has for its object a thread brake of the aforementioned Specify as well as a thread delivery device with a thread brake, in which the Thread brake is easy to manufacture and very reliable, and the braking surface can be reliably centered and is extraordinarily uniform in the circumferential direction Receives deformation behavior. In the thread delivery device by means of the thread brake a minimally fluctuating braking effect with self-compensation can be achieved, which means that the tension in the drawn thread at increasing thread speed or increasing thread acceleration so little increases as possible so that the thread tension starts from a sensitive adjustable base voltage varies only slightly. There should also be a large adjustment range can be achieved, within which the braking effect can be adjusted very sensitively is

The object is achieved with the features of claims 1 and solved the features of the independent claim 17.

The thread brake is easy and inexpensive to manufacture, because the brake body with the integral and pre-bent slats, the outer ends of the slats connecting ring element and the annular braking surface a conveniently prefabricated Component is in which neither for manufacture nor for attachment in the Support structure adhesive or glue points are required. The slats produce their spring action between the inner and outer ring parts and in the circumferential direction uniform and with a large effective lever arm, the axial preload in the brake body is introduced through the support structure, which is on the stationary support can be supported There is a long-stroke elastic range with circumferential direction very uniform deformation behavior of the braking surface and one perfect centering of the braking surface on the trigger edge. Thanks to the long stroke The spring device automatically compensates for any deviations in the roundness of the trigger margin. Because no foam or elastomer materials and no detention areas are provided can be used over a long service life constant suspension that is not affected by aging or decomposition and ensure braking properties. It also ensures that because of the compensation of deviations from an exact circular shape of the trigger edge such deviations have no influence on the thread tension or the uniformity the braking effect over a full revolution of the thread take-off point. A particular advantage of the structure of the brake body is that it has a relatively long axial relative stroke between the one with through the pre-bent slats fixed orientation positioned braking surface and the support structure relatively constant (flat) spring characteristic, which gives a very sensitive adjustment the braking effect between very weak and very strong. This positive effect results from the fact that, thanks to the pre-bent slats, the range of variation of the braking effect can be distributed over a long adjustment stroke range.

In the thread delivery device, the support structure in the universal joint is supported on all sides, that ensures reliable centering. This is due to the Positive locking of the ring parts of the universal joint, which are not uncontrolled relative allow lateral movements, while the supporting structure is optimal Allow tilting position to avoid incorrect positions between assembly or production the support and the storage drum of the thread delivery device to compensate. The brake body is an easily replaceable wearing part.

The outer ring element is also advantageous in terms of production technology integral part of the brake body, e.g. according to claim 4, from a Metal foil cutting is produced, for example by etching or laser cutting the spaces between the slats, and their subsequent plastic Deformation in the curved configuration. So is a long-stroke first spring device integrated directly into the brake body, which additionally the braking surface in the one optimal working at the trigger edge ensures orientation. The braking surface therefore does not need due to the axial preload from a radial orientation to be deformed, especially when the braking effect is weak, e.g. for very thin threads, is cheap.

Alternatively, according to claim 3, the outer ends of the slats in one Plastic ring embedded, preferably injected, be part of the Brake body.

According to claim 5, the brake body sits positively in a version of the Supporting structure. The circlip, preferably made of plastic, is actually only needed for transport or assembly, and then prevents that Falling out of the brake body in the functional position of the thread brake remains fixed anyway by the axial preload.

A very even deformation behavior of the braking surface and a relative one To obtain soft brake body, the stretched length of each should according to claim 6 Lamella correspond to a multiple of the width of the braking surface, and are specified dimensions appropriate. Such small spaces lead too to the advantage that the thread cannot get caught there.

According to claim 7, the lamellae are almost to or completely up to an approximately radial Orientation or even more pre-bent, initially being the generator can continue the tapered braking surface. The ring element expediently stands of the brake body radially, which is the attachment of the brake body in the Support structure simplified. Due to the plastic pre-bending of the slats before installation the thread brake can be used to adjust the long stroke of the soft, integrated Predetermine spring device.

According to claim 8, multiple pre-bending (serpentine course) of the slats a large adjustment stroke with a long effective length of the slats and achieve softer characteristics.

To the softness of the first spring device or the effective length of the slats given the radial installation space for the thread brake, the slats according to claim 9 can deviate from a radial course to form.

According to claim 10 is a for the self-centering of the thread brake and desirable sluggish working behavior of the braking surface favorable transmission principle chosen for the axial preload. The result is a kinematic Chain in power transmission from the support to the braking surface where the Force over an axially large-stroke elastic range in the thread brake of relative far inside first out into the ring element of the brake body and then from the outside through the plates back into the braking surface. This long and for the elasticity favorable power transmission path is despite the radial and the axial direction given the limitation of the installation space by the structuring the thread brake achieved.

The spokes that make up the outer ring are particularly useful connect to the seat ring of the support structure, spiral spring arms that provide an additional Define large stroke and soft spring devices in the thread brake. Through the two spring devices acting in series in the thread brake have several advantages achieved, e.g. a particularly large adjustment stroke, good self-centering, the optimal compensation of misalignments, and extensive decoupling of the Braking surface that behaves very passively or dead during operation, i.e. not undesirable looks dynamic. The latter is important at high thread speeds. Conveniently, are the spring hardnesses of the first and second spring devices approximately Similar, so that both spring devices work actively in operation. The large-stroke Adjustment range is particularly useful to adjust the braking effect sensitively. The supporting structure is nevertheless relatively rigid in the transverse direction and against torsion, and only relatively soft in the axial and tilt directions.

According to claim 12, leaf springs are expediently used as spokes of the supporting structure 5, e.g. eight flat leaf springs. The number of Discs in the brake body can be up to 200 or more in order to achieve a high Achieve homogeneity in power transmission.

The dimensioning of the leaf springs according to claim 13 is advantageous.

According to claim 14 with the two series connected spring devices and the transmission of power from far inside to outside and back inside a total get long-stroke soft thread brake, in which the braking surface is a very shows uniform deformation behavior

For a largely uniform braking effect in the circumferential direction, it is furthermore According to claim 15 particularly advantageous if the seat ring of the support structure Universal joint component is a one with a stationary counter-engagement element Universal joint forms in which the thread brake is perfectly centered in a form-fitting manner is, however, has the degree of freedom of all-sided tilting movements, if necessary existing manufacturing or assembly tolerances between the stationary support and to compensate for the storage drum.

According to claim 16, the main components of the thread brake are free of liability and detachably connected, prefabricated individual components.

In the thread delivery device according to claim 18, the thread brake is able to start very low from a set base tension of the thread to be drawn off To ensure fluctuations in thread tension, i.e. an effective one To perform self-compensation effect, according to the high thread speeds or strong thread accelerations no appreciable increase in thread tension cause, but in operation an optimal, low fluctuation thread tension profile is achievable. The range of variation of the braking effect, starting from one very weak braking effect, is distributed over a long adjustment stroke. The base voltage or the braking effect can be set very sensitively.

According to claim 19, the entire, between the storage drum and the arm usable space for the power transmission and the long-stroke elasticity of the Thread brake used. However, access to the Storage drum and in the area between the storage drum and the trigger eye available.

Fig. 1

perspektivisch eine Teilansicht eines Fadenliefergerätes mit einer Fadenbremse,

Fig. 2

eine Perspektivansicht der Fadenbremse,

Fig. 3

eine Explosionsdarstellung der Fadenbremse,

Fig. 4

einen Axialschnitt des Abstützungsbereiches der Fadenbremse im Fadenliefergerät, und

Fig. 5 A;B;C

drei schematische Krümmungsformen der Lamellen des Bremskörpers.

An embodiment of the subject matter of the invention is described with the aid of the drawing. Show it:

Fig. 1

perspective a partial view of a thread delivery device with a thread brake,

Fig. 2

a perspective view of the thread brake,

Fig. 3

an exploded view of the thread brake,

Fig. 4

an axial section of the support area of the thread brake in the thread delivery device, and

Fig. 5 A; B; C

three schematic forms of curvature of the plates of the brake body.

In Fig. 1 is a thread delivery device F, only indicated with its front part, for example for supplying a loom with a weft, indicated, the one has stationary storage drum T with a storage area 1, which has a for example, rounded trigger edge 3 which is continuous in the circumferential direction circular course is transferred from a front side 2 of the storage drum T. Housing, not shown, of the thread delivery device F extends a housing-fixed Boom 4 along the side of the storage drum T to beyond the front 2. The Boom 4 carries an arm 5 which is axially along the Boom 4 is adjustable. The arm 5 carries a pull-off eye coaxially with the storage drum T. 7 for the thread to be drawn off the weaving machine and forms a stationary one Support A for a thread brake B, the task of which is in the side by side Windings stored on the storage area 1 and through the Pull-off eye 7 axially overhead of the pull-off edge 3 thread pulled off with a braking as uniform a braking effect as possible, with the braked weft thread when pulling around the trigger edge 3 rotates.

The thread brake B works with a self-compensating effect, i.e. you apply one certain basic tension set braking effect adapts to the thread speed or thread acceleration so that a largely constant tension profile is maintained in the withdrawn thread regardless of whether the thread subtracted slowly or quickly or with strong or weak acceleration becomes. For this purpose, the thread brake has a continuous, circumferential flat and conical braking surface C on a thin-walled brake body D, which is supported in the support A by means of a support structure T such that the Brake surface C with an adjustable axial contact force against the trigger edge 3 is pressed. The braking surface is deformable perpendicular to its surface normal, tensile strength in the circumferential direction, and deforms with a rotating shaft in the rotating Draw-off area of the thread.

The brake body D is, for example, a circular ring which is closed in the circumferential direction from a metal foil, e.g. made of a beryllium copper alloy, with a small wall thickness (e.g. 0.1 to 0.8 mm), the annular braking surface C being radiated by slats L striving outwards towards a closed ring element R. with which the brake body D in an outer edge region or outer ring 8 of the support structure T is fixed. Extend from the outer ring 8 of the support structure Spokes 9 to form a seat ring 10, which is designed as a counter-engagement element 11 Ring element of the support A in the manner of a universal or ball joint K works together, its hinge center approximately in the extension of the storage drum axis is positioned.

The fins L are plastically deformed so that they have an arch curvature, whose concave curvature side faces the support structure T. Define the slats L. Bending springs, which result in a total of a first spring device S1 in the brake body. The spokes 9 are also curved spiral spring arms and form a second spring device S2 within the support structure T.

Alternatively, the support structure T could only consist of the outer ring 8, which in one annular support, not shown, is supported directly in the boom 4.

In Fig. 2, the thread brake B is a unit U, which is simply in the thread delivery device F, for example according to FIG. 1, can be used or replaced again. The Support A, from which an axial preload on the conical, in the circumferential direction Continuous braking surface C of the brake body D is transferred to essential smaller diameter d3 than the inner diameter d1 of the braking surface C, and at a considerable axial distance from it. The power transmission takes place first from the inside to the outside via the second spring device S2, expediently the spokes 9 have an arc of curvature facing the brake body D. have concave curvature side 15. The spokes expediently exist 9 (radial spokes) made of leaf spring 14, the ends of which on the seat ring 10 and on the outer ring 8 are firmly anchored, and in between the expediently harmonic Follow curvature. This means that the outer ring 8 relative to the seat ring 10 axially spring can and is also able to perform relative tilting movements. In the embodiment shown, eight spokes 9 are provided. The The number of spokes can also be larger or smaller. The radial spokes 9 are arranged with even intervals. The strengths of the leaf springs 14 can be between 0.1 and 1.0 mm, their width is about 3 to 10 mm, preferably at about 4 to 5 mm. It can be steel (spring steel) leaf springs act, or leaf springs made of plastic or composite material. It is conceivable The strength or width of the leaf springs vary over their length to a particular one To achieve spring behavior.

The outer ring 8 has a considerably larger diameter d2 than the inner diameter d1 of the braking surface C. For example, the diameter d2 can be up to approx. 180 % of d1, while the diameter d3 is approximately 40% of d1. The outer ring 8 is dimensionally stable. From him the force on the brake body D or its Transfer plates L inwards to braking surface C. The length is the spiral spring plates L a multiple of the width of the tapered braking surface C. In a specific embodiment, more than 200 plates L in the brake body D can be provided integrally, narrow between the spiral spring lamellae Gaps 13 (0.1 to 0.3 mm) are formed. Since the spaces 13 approximately have constant width, the slats widen starting from the Slightly outward braking surface C. The strength of the brake body made up of one circular, closed metal foil blank can be shaped, e.g. out Beryllium copper, for example, can be between 0.1 mm and 0.8 mm. The gaps 13 can be formed by etching or laser cutting. The curvature the fins L is, for example, under the influence of pressure and temperature made in a mold by plastic deformation, so that even without Preload the thread brake a cone angle uniform in the circumferential direction for the braking surface C is observed. The brake surface C continuing to the outside Slats L can initially in the direction of the generatrix of the conical surface the braking surface C and only gradually deviate outwards later, see above that they have an approximately radial orientation at their ends (almost radial, radial, or even bent over or bent several times in a serpentine shape, accordingly 5A, 5B, 5C).

2 is a locking ring for fixing the brake body D in the support structure T. 12 indicated, the detachable, e.g. snap-in, is connected to the outer ring 8 and clamps the outer edge region of the brake body D.

In the seat ring 10, the for the possibly desired universal or ball joint function the support A (Fig. 1) with a counter-engagement element not shown in Fig. 2 must cooperate, a seat 16 may be shaped.

In Fig. 3, the three components T, D, 12 of the thread brake B are in an exploded view arranged. In the support structure T with its outer ring 8, the spokes 9 and the seat ring 10, the radial spokes 9 form the second spring device S2, thanks to which the outer ring 8 axially and tiltably resilient against the Seat ring 10 is supported. In the outer ring 8, a ring socket 18 for the brake body D, and possibly also the locking ring 12 (dashed indicated) in order to fix or replace the brake body. The suspension characteristics the spring devices S1, S2 should be similar to one another or almost be equal.

In Fig. 3, the braking surface C continuing to the outside are arranged in a beam Slats L, whose concave curvature side 17 faces the support structure T. their outer ends in one piece in a concentric to the braking surface C ring element R are connected to each other. This ring element R is by means of the retaining ring 12 set in the version 18 of the outer ring 8, the locking ring 12 for snapping in with projections or a circumferential locking flange 19 can be equipped. The radial width of the locking ring 12 corresponds approximately the radial width of the ring element R. The orientation of the ring element R is chosen so that this lies approximately in a radial plane of the brake body D. The Ring element R could also be conical.

Alternatively, it would be conceivable to make the brake body D from a metal or plastic film with free-ended slats L and the outer ends of which are sprayed on To connect the plastic ring (similar to the circlip 12) to each other, this plastic ring then both the ring element R of FIG. 3 and the 3, with which the brake body D in the Support structure T is attached.

In a specific embodiment, the brake body D has an outer diameter of approx. 180 mm, while the diameter d1 is approx. 115 mm. This follows with a radial width of the blank for the brake body D of approx. 40 mm. The Seat ring 10 has an inner diameter d3 of approximately 45 mm and is from the outer ring 8 spaced axially by approx. 40 mm. Thanks to the curvature of the slats L is located the braking surface C in the interior of the support structure, such that its larger diameter in a side view approximately coincides with the rear contour of the outer ring 8, if thread brake B is not installed The spring hardness of the first spring device S1 formed in the slats is approximately equal to the spring hardness the second spring device S2.

4, the universal or ball joint K can be seen in the area of the support A, in which the thread brake B tilts around the central axis of the storage drum T or the thread brake B is able to perform properly on Center trigger margin 3. The seat ring 10 of the support structure T sits with its bearing surface 16 on a e.g. spherical bearing surface 20 of the counter-engagement element 11 which is attached to the arm 5 and surrounds the trigger eyelet 7 approximately concentrically. The bearing surface 20 is delimited on the inside by an annular flange 19, which is also a Swing or tilt limitation for the support structure T causes.

The ball joint K can be useful to center the thread brake on Trigger edge 3 of the storage drum T to improve. Because of the flexibility or Softness that is reflected in the thread brake thanks to the series-connected first and second spring devices S1 and S2, the seat ring 10 could alternatively also be firmly supported on the arm 8, i.e. without universal joint function. The locking ring 12 as the third component of the thread brake B could be omitted if the Brake body D is integrated directly into the support structure, e.g. by injection molding the Outer ring 8 around the ring element R or over the free ends of the spiral spring slats L. Then when replacing a worn brake surface C or the support structure T can also be replaced to replace the brake body.

Claims (19)

1. Yarn brake (B) for a yarn feeder (F), comprising an annular and thin-walled braking body (D) having a circumferential continuous conical braking surface (C), which braking body is mounted via a first spring assembly (S1) in an annular carrier structure (T) arranged at a side of the braking body facing away from said braking surface (C), said carrier structure being mountable at a stationary support (A), characterised in that said conical braking surface (C) of said braking body (D) is continued unitarily by a plurality of springy lamellas (L) extending outwardly essentially in a star-like fashion, said lamellas being formed - in a radial section of said braking body (D) - with a pre-shaped arc curvature and being interconnected at radial distance from said braking surface by an outer ring element (R), and that said lamellas constitute said first spring assembly (S1) within said braking body (D).
2. Yarn brake as in claim 1, characterised in that the outer ring element (R) is formed unitarily with said lamellas (L).
3. Yarn brake as in claim 1, characterised in that said outer ring element (R) is a form part made of plastic or metal material receiving the ends of said lamellas (L).
4. Yarn brake as in claim 1, characterised in that said braking body (D) is an annular blank of a metal foil in which said arc curvature of said lamellas (L) is made by bending them with plastic deformation by application of temperature and/or pressure.
5. Yarn brake as in claim 1, characterised in that said carrier structure (T) comprises a form stable outer ring (8) with a round socket (18) for said ring element (R) of said braking body (D), and that said ring element (R) is detachably mounted in said socket (18) by means of a plastic and/or metallic securing ring (12).
6. Yarn brake as in claim 1, characterised in that the stretched length of each lamella (L) corresponds to the four- to eight-fold width of the braking surface (C), that the circumferential width of each lamella (L) is between about 0.5 mm and about 1.5 mm, and that interspaces (13) provided between said lamellas have a width between about 0.1 mm and 0.5 mm.
7. Yarn brake as in claim 1, characterised in that each lamella (L) extends outwardly in the direction of the cone generatrice of the braking surface (C) and is gradually pre-bent to an essential radial or radial orientation or beyond a radial orientation, and that the outer ring element (R) is situated in a radial plane of the braking body (D).
8. Yarn brake as in claim 1, characterised in that each lamella (L) is pre-shaped like a snake line between said braking surface (C) and the outer ring element (R).
9. Yarn brake as in claim 1, characterised in that - in an axial view of braking body (D) - said lamellas (L) deviate obliquely or curved from a radial orientation.
10. Yarn brake as in claim 1, characterised in that the carrier structure (D) consists of a form stable outer ring (8), a seat ring (10) axially spaced apart from the plane of said outer ring (8), said seat ring (10) having considerably smaller diameter (d3) than said outer ring (8), and of regularly distributed spokes (9), like radial spokes, interconnecting said outer ring (8) and said seat ring (10).
11. Yarn brake as in claim 10, characterised in that said spokes (9) are designed as bending spring arms to resiliently connect said outer ring (8) with said seat ring (10) in an axial movable and tiltable fashion, that said bending spring arms constitute in said yarn brake (B) a second spring assembly (S2) integrated into the carrier structure (T), the at least axial spring property of said second spring assembly (S2) being made similar to the axial spring property of said first spring assembly (S1), and that the second spring assembly (S2) is relatively stiff in lateral and torsional directions.
12. Yarn brake as in one of claims 10 or 11, characterised in that said bending spring arms are leaf springs (14) mounted in bent condition, the ends of which are firmly connected with the outer ring (8) and the seat ring (10), respectively.
13. Yarn brake as in claim 12, characterised in that said leaf springs (14) have a thickness of about 0.1 mm to about 1.0 mm and a width of about 4.0 mm to about 10.0 mm, preferably about 5.0 mm.
14. Yarn brake as in at least one of the preceding claims, characterised in that said seat ring (10) has an inner diameter (d3) smaller than the inner diameter (d1) of said braking surface (C) e.g. about 40% of said inner diameter (d1), and that said outer ring (8) has a diameter (d2) bigger than said inner diameter (d1) of said braking surface, like about 160% of said inner diameter (d1).
15. Yarn brake as in at least one of the preceding claims, characterised in that said seat ring (10) is formed as a universal joint component form-fitted onto a stationary counter-engagement element (11) of said stationary support (A).
16. Yarn brake as in at least one of the preceding claims, characterised in that at least said braking body (D) and said carrier structure (T) are prefabricated single components of a structural unit (U) and are detachably positively connected without bonding spots.
17. Yarn feeder (F) having a yarn brake (B), said yarn feeder (F) comprising a stationary storage drum (T') forming a frontal withdrawal rim (3) which is continuous in circumferential direction, a housing bracket (4) with a stationary support (A) for said yarn brake (B), said yarn brake (B) comprising an annular, thin-walled radially deformable braking body (D) with a circumferentially continuous conical braking surface (C), said braking body (D) mounted via a first spring assembly (S1) in an outer ring of a cup-shaped, hollow carrier structure (T) supported at support (A) to axially and yieldably press said braking surface (C) against said withdrawal rim (3), characterised in that said carrier structure (T) is supported sidewardly tiltably by a universal joint (K) at said support (A) the universal joint centre essentially coinciding with the centre axis of said storage drum (3), and that said universal joint (K) consists of two positively interengaging ring parts, one of which defined by a seat ring (10) of said carrier structure (T), the other of which being a ring-shaped counter-engagement element (11) formed with a spherical bearing surface (20).
18. Yarn feeder as in claim 17, characterised in that said braking body (D) is a closed circular ring made of a metal foil with its braking surface (C) bordering the inner ring diameter (d1) and with a plurality of elastic lamellas (L) unitarily continuing said braking surface outwardly in star-like fashion, said lamellas constituting said first spring assembly (S1) of said yarn brake, that said lamellas are interconnected within said braking body (D) radially distant from said braking surface (C) by a ring element (R) mounted to said carrier structure (T), that said lamellas (L) have a pre-shaped arc curvature - seen in a radial section of said braking body - with the concave curvature side (17) facing the inner side of said carrier structure (T), that said carrier structure (T) has spokes (9) connect said outer ring (8) and said seat ring (10) and constitute a second spring assembly (S2) of said yarn brake (B), that the braking body (D) is held in said carrier structure (T) with considerable radial distance from said braking surface (C), and that said seat ring (10) is supported at said support (A) with considerable radial distance inside of said braking surface (C) and with axial distance from said braking surface (D).
19. Yarn feeder as in claim 17, characterised in that the ring-shaped counter-engagement element (11) surrounds a withdrawal eyelet (7) of said yarn feeder (F) and is mounted on an arm (5) which is axially displaceable in said housing bracket (4).

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